CA1263996A - Process for polymerizing a monomer charge - Google Patents
Process for polymerizing a monomer chargeInfo
- Publication number
- CA1263996A CA1263996A CA000504612A CA504612A CA1263996A CA 1263996 A CA1263996 A CA 1263996A CA 000504612 A CA000504612 A CA 000504612A CA 504612 A CA504612 A CA 504612A CA 1263996 A CA1263996 A CA 1263996A
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- reaction zone
- carbon atoms
- gas
- ethylene
- support
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Abstract
Abstract of the Disclosure Process of polymerizing a monomer charge including ethylene by (1) drying an inorganic oxide having surface hydroxyl groups to form a support that is substantially free of adsorbed water, (2) reacting the surface hydroxyl groups of the support with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the formula RxM'yR''z, wherein M is a metal of Group III
of the periodic table, R is all alkyl group containing 1 to 12 carbon atoms, R' and R" are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x, (3) reacting the thus-treated support with at least about 0.001 mol, per mol of organometallic compound, of at least one vanadium compound corresponding to a formula selected from (RO)nVOX3-n and (RO)mVX4-m, in which formulas R represents a C1-C18 monovalent hydrocarbon radical that is free of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4, (4) reacting the product of step 3 with at least about 0.1 mol, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms, (5) feeding the product into a gas-phase reaction zone, (6) feeding a trialkylaluminum into the gas-phase reaction zone in order to form a bed comprising the product and the trialkylaluminum, (7) fluidizing the bed with a gas mixture including ethylene, hydrogen and chloroform, (8) removing particulate polymerized substantially ethylene particles from the reaction zone, and (9) recycling unreacted gas mixture from the top of the reaction zone to the bottom of the reaction zone.
of the periodic table, R is all alkyl group containing 1 to 12 carbon atoms, R' and R" are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x, (3) reacting the thus-treated support with at least about 0.001 mol, per mol of organometallic compound, of at least one vanadium compound corresponding to a formula selected from (RO)nVOX3-n and (RO)mVX4-m, in which formulas R represents a C1-C18 monovalent hydrocarbon radical that is free of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4, (4) reacting the product of step 3 with at least about 0.1 mol, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms, (5) feeding the product into a gas-phase reaction zone, (6) feeding a trialkylaluminum into the gas-phase reaction zone in order to form a bed comprising the product and the trialkylaluminum, (7) fluidizing the bed with a gas mixture including ethylene, hydrogen and chloroform, (8) removing particulate polymerized substantially ethylene particles from the reaction zone, and (9) recycling unreacted gas mixture from the top of the reaction zone to the bottom of the reaction zone.
Description
991~;
712~5-8 This invention relates to the polymerization of olefins. More particularly, this invention relates to a process having catalyst compositions which are useful for polymeriz.ing one or more monomers comprising ethylene to polymers havlng a na~row molecular weight distributio:n and a good balance of physical properties.
It is known that catalysts of the type variously described as coordination, Ziegler, Ziegler-type, or Ziegler-Natta catalysts are useful for the polymerization of olefins under moderate conditions at temperature and pressure.
It is also know~ that the properties of the polymers obtainable by the use of such catalysts, as well as the relative economies of the processes used to prepare the poly-mers, vary with several factors, including the choice of the particular monomers, catalyst components, polymerization adjuvants, and other polymerization conditions employed.
During the years since Ziegler catalysts were first publicly disclosedJ there has been a considerable amount of research conducted on the use of such catalysts; and numerous publications have resulted from that research. ~hese publications have added much to the knowledge of how to make various types of olefin polymers by various types of processes. However, as is apparent from the amount of
712~5-8 This invention relates to the polymerization of olefins. More particularly, this invention relates to a process having catalyst compositions which are useful for polymeriz.ing one or more monomers comprising ethylene to polymers havlng a na~row molecular weight distributio:n and a good balance of physical properties.
It is known that catalysts of the type variously described as coordination, Ziegler, Ziegler-type, or Ziegler-Natta catalysts are useful for the polymerization of olefins under moderate conditions at temperature and pressure.
It is also know~ that the properties of the polymers obtainable by the use of such catalysts, as well as the relative economies of the processes used to prepare the poly-mers, vary with several factors, including the choice of the particular monomers, catalyst components, polymerization adjuvants, and other polymerization conditions employed.
During the years since Ziegler catalysts were first publicly disclosedJ there has been a considerable amount of research conducted on the use of such catalysts; and numerous publications have resulted from that research. ~hese publications have added much to the knowledge of how to make various types of olefin polymers by various types of processes. However, as is apparent from the amount of
- 2 ~
L2~i3996 I research on Ziegler catalysis that is still being conducted l throughout the world, as well as the number of patents that ¦! are still being issued to lnventors working in the field of il Ziegler catalysis, the means of attaining certain results I! when polymerizing olefins with Ziegler catalysts are still frequently unpredictable. The fact that this situation exists is sometimes due to the need to obtain a ¦ previously-una-ttainable combination of results; occasionally due to difficulties in obtainin~ the same results in a il commercial-scale apparatus as in a laboratory-scale reactor;
¦l and often due to a polymerization parameter's having an effect, or side-effect, in a given type of polymerization ¦I process that is dlEFerellt Erom effects achieved by its use in ¦I prior art processes of a diEEerent type.
One aspect oE Ziegler catalysis in which the need ¦¦ for further research has been found to exist has been in -the provision of catalyst compositions suitable for ~se in a ¦! commercially-feasible process for preparing ethylene polymers ¦having a narrow molecular weight distribution and a good balance of physical properties. Such polymers have jlparticular application in the production of articles that are ! formed by injection molding; typically have molecular weight distributions such that their normalized V30/V300 melt viscosity ratios are in the range of about 1.5 to 2.3, with the ratios in the lower portion of this range being generally preferred but difficult to attain with known processes that ¦might otherwise be commercially feasible; and - like other jlpolymers intended for commercial use - are desirably prepared iby a process which is as economical as possible as well as being capable of producing a polymer having the desired llproperties.
., . I
L2~i3996 I research on Ziegler catalysis that is still being conducted l throughout the world, as well as the number of patents that ¦! are still being issued to lnventors working in the field of il Ziegler catalysis, the means of attaining certain results I! when polymerizing olefins with Ziegler catalysts are still frequently unpredictable. The fact that this situation exists is sometimes due to the need to obtain a ¦ previously-una-ttainable combination of results; occasionally due to difficulties in obtainin~ the same results in a il commercial-scale apparatus as in a laboratory-scale reactor;
¦l and often due to a polymerization parameter's having an effect, or side-effect, in a given type of polymerization ¦I process that is dlEFerellt Erom effects achieved by its use in ¦I prior art processes of a diEEerent type.
One aspect oE Ziegler catalysis in which the need ¦¦ for further research has been found to exist has been in -the provision of catalyst compositions suitable for ~se in a ¦! commercially-feasible process for preparing ethylene polymers ¦having a narrow molecular weight distribution and a good balance of physical properties. Such polymers have jlparticular application in the production of articles that are ! formed by injection molding; typically have molecular weight distributions such that their normalized V30/V300 melt viscosity ratios are in the range of about 1.5 to 2.3, with the ratios in the lower portion of this range being generally preferred but difficult to attain with known processes that ¦might otherwise be commercially feasible; and - like other jlpolymers intended for commercial use - are desirably prepared iby a process which is as economical as possible as well as being capable of producing a polymer having the desired llproperties.
., . I
3~3~36 There are, of course, known processes ~or preparing ln~CCtiOn molding resins by polymerizing ethylene with tlle aid of Ziegler catalysts. However, the known processes typically suffer one or more of the disadvantages of lack of economy, inability to produce polymers having a suitable l balance of properties, and/or unreliability in producing such li polymers - particularly in commercial-scale operations.
ll U.S. Patent No. 4,003,712 by Miller teaches a ¦I gas-phase fluidized bed system and process which are capable of being scaled up to commercial size and, being a~
' solvent-free, would be less expensive than processes which jl use solvents or liquid diluents. However, Miller's silyl i chromate catalyst does not give polyrners oE the clesired I! rnolecular we:ight distribution and good balarlcc o~ physical ¦¦ properties. ~Iis system contairls some Eeat~lres which tend to ¦ shorten commercial "on-stream" time. He does not teach how l! to avoid polymer buildup on reactor surfaces; a phenomenon ¦¦ variously referred to as "coating", "fouling", or "sheeting".
What is still needed is a process employing a ¦i catalyst which (a) is suitable for use in a gas-phase polymerization process, (b) is capable of yieldlng polymers ¦ having a narrow molecular weight distribution and a good ¦ balance of physical properties, (c) has sufficient activity to be economically attractive, (d) does not cause reactor il wall fouling,~and (e) a gas-phase fluidized bed process which ~l allows the catalyst to perform at its full potential at commercial scale.
British Patent No 1,489,410 (Monsanto~ teaches !i gas-phase polymerization processes which, because of their use of supported Ziegler catalysts havlng a vanadium component and other factors, are commercially attractive processes. However, as taught in the patent, the processes ¦ are designed to result in the formation of polymers having ,j the broad molecular weight distributions suitable for blow 'I molding resins rather thal. the narrower molecular weight , ~ 4-94~3~>
distributions needed for injection molding resins: and the patent itself does not suggest how its processes might be modified to result in the formation of polymers having narrower molecular weight distributions. Attempts to make the processes of the Monsanto patent suitable for the preparation of injection molding resins by combining its teachings with the teachings of publications that discuss means of narrowing molecular weight distribution have not been successful. For example, polymers having a sufficiently narrow molecular weight distribution have not been obtained when Monsanto's preferred vanadium halides have been replaced with the alkoxy group-containing vanadium compounds which are within the scope of their patent and which U.S. Patent Nos.
3,457,244 ~E`ukuda et al.) and 3,655,583 (Yamamoto et al.) teach to result in the production of polymers havirlcJ narrow~r molecular weight distributions when unsupported cataLy~t systems are employed.
~ .S. Patent No. 2,965,626 hy Pilar et al discloses polymerizing organic compounds containing ethylenic unsatuation under relatively mild polymerization conditions with catalysts and alcohol catalyst promoters. More specifically Pilar et al found that the polymerization activity of the catalyst prepared by reaction of alkali reagents with the specified metal salts can be ~ubstantially increased by the inclusion of an alcohol in the reaction zone. U.S. Patent No. 3,163,611 by Andersen et al pertains to the production of high density polyethylene by polymerizing ethylene in the presence of a catalyst exempli~ied by the material obtained by the interaction of a trialkylaluminum with titanium tetrachloride.
U.S. Patent No. 3,202,645 to Yanc~y presents a process for polymerizing and copolymerizing alpha mono and dl-oleflns by catalysts comprising ~a) the product of the !l ~
I,j I
~, j 1, ~ 3~3~
I reaction bet~een a compound of a metal choscn from the gr~up I consisting of the metals of Group IIb and IIIb (where the qroup numbers correspond to the Mendeleev Periodic Table) and hydroxyl groups on the surface of a finely-divided j particulate inorganic solid, preferably finely-divided silica or alumina, and ~b) a halide-type compound of a Group IVa, V, ¦¦ VIa, VIIa, or p riod 4 of Group VIII metal. The li polymerization ~f copolymerization reaction can be effected ¦¦ at suitable te~peratures within the range of from about - 25 ¦I C. to about 250 C., and pressures ranging from below '¦ a-tmospheric upwardly to any desired maximum pressure, for example, 3~,000 p.s.i.g. or even higher pressures. U.S.
j Patent No. 3,718,636 to Stevens et al teaches obtaining Il polyolefins having a wide distribution of molecular weights ¦¦ through~the use of a catalyst eomprising an organom~tallic compound, and a solid complex component obtained by reactin~
a solid bivalent met~l compound with an impregnation agent which consists of an organometallic compound, separating the solid reaction product, and reaeting the solid reaction product with a halogenated derivative of a transition metal.
Stevens et al teaehes in U.S. Patent No. 3,787,384 another l catalyst suitable for use in olefin polymerization and olefin ¦ copolymerization which comprises (a) at least one organometallic compound, and jl (b) a solid eatalytic component obtained by reacting a sUpport composed of silica, alumina or both silica and alumina wlth a compound of the formula MRnXm n in which M
i is aluminum or magnesium, R is a hydrocarbon radical ¦¦ containing 1 to 20 carbon atomst X is hydrogen or a halogen, ¦I m is the valence of M, and n is a whole number not less than ¦~ 1 nor greater than m, separating the solid product of the reaction, reacting said product with an excess of a halogen-containiny transition metal compound, and separating , the solid reaction product.
j U.S. Patent No. 3,925,338 to Ort teaches that l control of particle size of olefin polymers produced by i -6-/ ~ 3~
gas-phase polymerization of at least one ~lefin ~sing Ziegler-type catalysts deposited on solid supports in a fluidized-solids operation is effected by controlling the particle size of the catalyst support. U.S. Patent No.
ll U.S. Patent No. 4,003,712 by Miller teaches a ¦I gas-phase fluidized bed system and process which are capable of being scaled up to commercial size and, being a~
' solvent-free, would be less expensive than processes which jl use solvents or liquid diluents. However, Miller's silyl i chromate catalyst does not give polyrners oE the clesired I! rnolecular we:ight distribution and good balarlcc o~ physical ¦¦ properties. ~Iis system contairls some Eeat~lres which tend to ¦ shorten commercial "on-stream" time. He does not teach how l! to avoid polymer buildup on reactor surfaces; a phenomenon ¦¦ variously referred to as "coating", "fouling", or "sheeting".
What is still needed is a process employing a ¦i catalyst which (a) is suitable for use in a gas-phase polymerization process, (b) is capable of yieldlng polymers ¦ having a narrow molecular weight distribution and a good ¦ balance of physical properties, (c) has sufficient activity to be economically attractive, (d) does not cause reactor il wall fouling,~and (e) a gas-phase fluidized bed process which ~l allows the catalyst to perform at its full potential at commercial scale.
British Patent No 1,489,410 (Monsanto~ teaches !i gas-phase polymerization processes which, because of their use of supported Ziegler catalysts havlng a vanadium component and other factors, are commercially attractive processes. However, as taught in the patent, the processes ¦ are designed to result in the formation of polymers having ,j the broad molecular weight distributions suitable for blow 'I molding resins rather thal. the narrower molecular weight , ~ 4-94~3~>
distributions needed for injection molding resins: and the patent itself does not suggest how its processes might be modified to result in the formation of polymers having narrower molecular weight distributions. Attempts to make the processes of the Monsanto patent suitable for the preparation of injection molding resins by combining its teachings with the teachings of publications that discuss means of narrowing molecular weight distribution have not been successful. For example, polymers having a sufficiently narrow molecular weight distribution have not been obtained when Monsanto's preferred vanadium halides have been replaced with the alkoxy group-containing vanadium compounds which are within the scope of their patent and which U.S. Patent Nos.
3,457,244 ~E`ukuda et al.) and 3,655,583 (Yamamoto et al.) teach to result in the production of polymers havirlcJ narrow~r molecular weight distributions when unsupported cataLy~t systems are employed.
~ .S. Patent No. 2,965,626 hy Pilar et al discloses polymerizing organic compounds containing ethylenic unsatuation under relatively mild polymerization conditions with catalysts and alcohol catalyst promoters. More specifically Pilar et al found that the polymerization activity of the catalyst prepared by reaction of alkali reagents with the specified metal salts can be ~ubstantially increased by the inclusion of an alcohol in the reaction zone. U.S. Patent No. 3,163,611 by Andersen et al pertains to the production of high density polyethylene by polymerizing ethylene in the presence of a catalyst exempli~ied by the material obtained by the interaction of a trialkylaluminum with titanium tetrachloride.
U.S. Patent No. 3,202,645 to Yanc~y presents a process for polymerizing and copolymerizing alpha mono and dl-oleflns by catalysts comprising ~a) the product of the !l ~
I,j I
~, j 1, ~ 3~3~
I reaction bet~een a compound of a metal choscn from the gr~up I consisting of the metals of Group IIb and IIIb (where the qroup numbers correspond to the Mendeleev Periodic Table) and hydroxyl groups on the surface of a finely-divided j particulate inorganic solid, preferably finely-divided silica or alumina, and ~b) a halide-type compound of a Group IVa, V, ¦¦ VIa, VIIa, or p riod 4 of Group VIII metal. The li polymerization ~f copolymerization reaction can be effected ¦¦ at suitable te~peratures within the range of from about - 25 ¦I C. to about 250 C., and pressures ranging from below '¦ a-tmospheric upwardly to any desired maximum pressure, for example, 3~,000 p.s.i.g. or even higher pressures. U.S.
j Patent No. 3,718,636 to Stevens et al teaches obtaining Il polyolefins having a wide distribution of molecular weights ¦¦ through~the use of a catalyst eomprising an organom~tallic compound, and a solid complex component obtained by reactin~
a solid bivalent met~l compound with an impregnation agent which consists of an organometallic compound, separating the solid reaction product, and reaeting the solid reaction product with a halogenated derivative of a transition metal.
Stevens et al teaehes in U.S. Patent No. 3,787,384 another l catalyst suitable for use in olefin polymerization and olefin ¦ copolymerization which comprises (a) at least one organometallic compound, and jl (b) a solid eatalytic component obtained by reacting a sUpport composed of silica, alumina or both silica and alumina wlth a compound of the formula MRnXm n in which M
i is aluminum or magnesium, R is a hydrocarbon radical ¦¦ containing 1 to 20 carbon atomst X is hydrogen or a halogen, ¦I m is the valence of M, and n is a whole number not less than ¦~ 1 nor greater than m, separating the solid product of the reaction, reacting said product with an excess of a halogen-containiny transition metal compound, and separating , the solid reaction product.
j U.S. Patent No. 3,925,338 to Ort teaches that l control of particle size of olefin polymers produced by i -6-/ ~ 3~
gas-phase polymerization of at least one ~lefin ~sing Ziegler-type catalysts deposited on solid supports in a fluidized-solids operation is effected by controlling the particle size of the catalyst support. U.S. Patent No.
4,232,140 also to Ort discloses the use of trichlorofluoromethane as a promoter il- the polymerization and copolymerization of ethylene with supported Ziegler-type vanadium compound/alkylaluminum compound catalysbs in the presence of hydrogen. Ort finds that polymer yields with his supp~rted vanadium-based catalysts are -too low for commercial viability unless the catalyst is promo-ted to high yield with the trichlorofluoromethane promoter. The viscosity ratio data in Ort's examples, which may be rela-ted to molecular weight distribution, indica-te that none of the polymers have narrow molecular weight distribution. Ort does not teach or suggest how to avoid reactor fouling.
Fukuda et al. also teach t~_~ethylene copolymers or terpolymers having narrow molecular weight distribution~ can be obtained by the use of an unsupported catalyst composition prepared by ~l~ mixing an alcohol containing l to 12 carbon atoms with VOC13 and then (2) mixing the mixture thus obtained with an alkylalwninum compQund in the presence of the monomers to be interpolymerized, and there are other patents, e.g., Stamicarbon's British Pat. No. 1,175,593 and U.S. Pat. Nos 3,535,269 (Tanaka e-t al.) 4,071,674 (Kashiwa et al.) and 4,~56,865 (Hyde et al.) which teach the use of catalyst compositions prepared by adding an alcohol at some stage during the catalyst preparation. However, although some of these patents are concerned with the production o~
polymers having narrow molecular weight distributions, none of them teaches a catalyst composition which ~ ~e~ the aforementioned need for a catalyst suitable for use in a commercially-attractive gas-phase polymerization process that is capable of producing injeCtion molding-grade polymers having a good alance cf physical prcperties.
i3'~3~3~i n object of the invention is to provide an il economical commercial polymerization process for preparinc3 ¦l ethylene polymers having narrow-to-intermediate molecular ¦l weight distributioll and a good balance of physical ~¦ properties.
¦ Another object is to provide non-fouling catalyst j compositions which are useful in an economical gas-phase ¦ process for polymerizing one or more monomers comprising . ethylene to polymers having a narrow-to-intermediate : ~ molecular weight distribution and a good balance of physical I properties.
¦ The foregoing objects of this invention are broadly ¦ accomplished by providing a process of polymerizing a monomer ¦ charge in~luding cthylene comprising the steps oE:
(a) drying an inorganic oxide having surface : hydroxyl groups to form a support that is substantially free of adsorbed water;
::: `\
~ ~b) reacting the surface hydroxyl groups of the :~: ; support with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the : I formula RXMR'yR"z, wherein M is a metal of Group III of the periodic table, R lS alkyl yroup containing 1 to 12 carbon atoms, R' and R" are independently selected from the group consisting of :~ jj H, Cl, and alkyl and alkoxy groups containing 1 to ; :il I2 carbon atoms, x has a value of 1 to 3, and y and z both represent values of O to 2, the sum of which .
l is not greater than 3-x;
,: 11 ':
(c) reacting the thus-treated support with at l~ least about 0.001 mol, per mol of ,j organometallic compound, of at least one vanadium I' ' I -8-~ij39'16 1 1~
/ I compound corresporlding to a formula sel~cted Erom .
! (RO) VOX3 and (RO)mVX4 m~ in which formulas R .
¦ rcyrescl~ts ~ Cl-C18 monovalent hydrocarbon radical j that is free of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4; .
Il (d) reacting the product of step (c) with at least ¦ about 0.1 mol, per mol of organometallic compound, ::i of an alcohol containing 1 to 18 carbon atoms;
ll (e) feeding the product of step ld) into a Il gas-phase reaction zone;
I! (~) Eeedillq, separc~t~ly and independerltly o said feedincJ step (e), a tr:ialkyl~luminum into the ¦ gas-phase reaction zone in order to form a bed in ¦ the gas-phase reaction zone which comprlses the product of step (d) and the trialkylaluminum;
(g) fluidizing the bed of step (f) at a pressure ¦ of between about 0.7 and 4.2 MPa and a temperature of between about 50 to 120 C. by difEusin~
underneath the bed of step (f) a gas mixture ¦ comprising ethylene, hydro~en, and chloroform at a ¦ rate sufficient enough to give a linear ~as jj velocity in the bed of step (f) of between about 15 I to 60 cm/sec;
¦l (h) removing particulate polymerized substantially Ill et ~ylene particles from the reactlon zone~ aDd il (i) recycling unreacted gas mixture of step (g) from the top of the reaction zone to the bottom of i,¦ the reaction zone.
Il .
i2~3~'3~3~i This invention is a novel process oE polymerizing a monomer charge having ethylene. An inorganic oxide with surface hydroxyl groups is dried to form a support that is substantially free of adsorbed water. The surface hydroxyl groups of the support are reacted with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the formula RXMR'yR'' , wherein M is a metal of Group III of the periodic table, R is an alkyl group containing 1 to 12 carbon atoms, R' and ~" are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x. The thus-treated support is reacted with at least about 0.001 mol, pcr mol oE organometallic compourld, of at least one vanadium compound corresponding to a Eormula selected from (RO)nVOX3 and (RO)mVX4 m~ in which formulas R
represents a Cl-C18 monovalent hydrocarbon radical that is r~e of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value oE 0 to 4. This product is reacted with at least about 0.1 mol, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms, in order to form a catalyst product. The catalyst product is fed into a gas-phase reaction zone.
Separately and independently of thic feeding, a trialkylaluminum is fed into the gas-phase reaction zone in order to forrn a bed in the gas-phase reaction zone which includes inter alia the catalyst product and the trialkylaluminum. The bed is fluidized at a pressure of between about 0.7 and 4.2 MPa and a temperature of between about 50 to 120 C by diffusing underneath the bed including the catalyst product and trialkylaluminum a gas mixturc comprising ethylene, hydrogen, and chloroform a~ a r~-itc 5ufficient enough to give a lil~ear gas velocity in ~*~
comprising catalyst product and trialkylaluminum of betwcen ~, il -10- 1 ~ i399~; i about 15 to 60 cm/sec. Particulate polymerized substantially ethylen~ particles arc relTloved from the reaction zone, and unreacted gas mixture of ethylene, hydrogen and chloroform is recycled from the top of the reaction zone to the bottom of the reaction zone.
The inorganic oxide used in preparing catalyst composition of the inven-tion may be any particulate inor~anic oxide or mixed oxide, e.g., silica, alumina, silica-alumina, magnesia, ~irconia, thoria, titania, etc., having surface hydroxyl groups capable of reacting with the organometallic compound. However, it is generally an inorganic oxide selected from the group consisting of silica, alumina, magnesia and mixtures thereof, i.e., physical mixtures, such as mlxt~res of silica and alumina particles, ctc., and/or chemical mixtures, ~ucll as magnesum silicate, aluminum silicate, etc. 'rhe surface hydroxy~ groups may be at the ou-ter surface of the oxide particles or at the surfaces of pores in the particles, the only requirement in this regard being that they be available for reaction with the organometallic compound.
The specific particle size, surface area, pore volume, and number of surface hydroxyl groups characteristic of the inorganic oxide are not critical to its utility in the practice of the ïnvention. However, since such characteristics determine the amount of inorganic oxide that it is desirable to employ in preparing the catalyst compositions, as well as sometimes affecting the properties of polymers formed with the aid of the catalyst compositions, these characteristics must Erequently be taken into consideration in choosing an lnoryanic oxide for use in a par-ticular aspect of the invention. For exampler when the catalyst composition is to be used in a gas-phase polymerization process - a type of process in wh:ich it is known that the polymer particle size can be varied by varying 1~3'3~36 l the particle size of the support - the inorganic oxide used in preparing the catalyst cornposition should be one having a particle size that is suitable for the production of a polymer having the desired particle size. In general, optimum results are usually obtained by the use~of inorganic oxides having an average particle size in the range of about 30 to 600 microns, preferably about 30 to lOG ~icrons; a surface area of about 50 to 1000 square meters per gram, ¦
preferably about 100 to 400 square meters per gram; and a pore volume of about 0.5 to 3.5 cc per gram, preferably about 0.5 to 2 cc per gram.
As indicated above, the organometallic compound that is reacted with the surface hydroxyl groups of the inorganic oxide in the practice of the invention may be any one or more organometallic compounds corresponding to the formula RXMR'yR"z, wherein M is ~ metal o~ Group III of the pel-iodic tabl~, R is an alkyl group containing 1 to 12 carbon atoms, R' and R" are independently selec~ed from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x. Thus, M may be, e~g. aluminum, gallium, indium, or thallium; R may be, e.g., methyl, ethyl, propyl, isopropyl, n-butyl, n-pentyl, isopentyl, t-pentyl, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, etc; R', when present, may be H, Cl, an alkyl group, such as one of those exemplified above for R, which is the same as or different from R, or an alkoxy group, such as the alkoxy groups corresponding to the aformentioned alkyl groups; and R", when present, may be any of the substituents mentioned above as exemplary of R' and may be the same as or different from R'.
The preferred organometallic compounds are those in which M is aluminum. Utilizable aluminum compounds include chlorides, such as dimethylaluminum chloride, diethylaluminum 2~j3~3~i chloride, dipropylal~mi~um chloride, diisobutylalumir-um chloride, the corresponding alkylalurninum dichlorides, etc., and mixtures of such chlorides, but the chloridcs are generally not particularly preferred because of the halogen residue they contribute to polymers made in -their presence.
The more preferred aluminum co~pounds are the trialkylaluminums, dialkylaluminum hydrides, dialkylalumlnum alkoxides, and alkylaluminum dialkoxides, such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, isoprenylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, trldodecylaluminum, etc.; the correspondinq alkoxy compounds wherein one or two of the alkyl groups have been replaced by alkoxy groups, such as ethylalumlnum diethoxide, dicthylalumirl~lm ethoxide, ethylalum.inum scs~uLethoxide, ethylaluminum diisopropoxide, etc.; diethylalumin-lm hydride, di-n-propylaluminum hydride, diisobutylaluminum hydride, etc.; and mixtures of such compounds.
Especially preferred aluminum compounds are the trialkylaluminums, particularly triethylaluminum and ¦tri-n-hexylaluminum, which are advantageous to employ because of their cost, availability, and/or efEectiveness. When a trialkylaluminum is used as the organometallic compound, it is generally found that - all other factors being constant -the molecular weight distribution of polymers prepared with the catalysts of the invention are narrowed as the chain lengths of the alkyl groups of the trialkylaluminum are lengthened.
The amount of organometallic compound employed is ¦¦at least substantially the stoichiometric amount, i.e., the ¦¦amount required to react with all of the available hydroxyl groups on the inorgarlic oxide. Use of an amount'less than the substantially stoichiometric amount would broaden the molecular weight distributions of polymers formed in -the l¦presence of the catalyst compositions; use of an amount !1, 1~ -13-3t36 ;i greater th~n the substantlally stoichiometic amount is permissable within the scope of the invention but frequently serves no practical purpose and can be disadvantageous in that the excess organometallic compound sometimes leads to fouling of the polymerization reactox if not removed from the catalyst composition prior to the composition's being used. ¦
When the number of available hydroxyl groups on the particular inorganic oxide being treated is not known, it can be determined by any conventional technique, e.g., by reacting an aliquot of the inorganic oxide with excess triethylaluminum and determining the amount of evolved ethane. Once the number of available hydroxyl groups on the inor~anic oxide is known, the amount of or~anometallic compound to be ernployed is chosen ~o a3 to prov:ide at lcast about one mol oE orcJanometall.ic compound per mol o~ availabLe hydroxyl groups.
The vanadium component of the catalyst compositions of the invention may be any one or more compounds corresponding to a formula selected from (RO)nVOX3 ~ and (RO)mVX4 m~ wherein R represents a monovalent hydrocarbon radical that contains 1 to 18 carbon atoms and is free of aliphatic unsaturation, X is C1 or Br, n has a value o 0 to 3, and m has a value of 0 to 4. Thus, the utilizable vanadium compounds include VOC13, VOBr3, and the indicated mono-, di-, and trihydrocarbyloxy derivatives thereof, as well as VC14, VBr4, and the indicated mono-, di-,. tri-, and tetrahydrocarbyloxy derivatives thereof; and R, when present, may be a straight- or branched-chain alkyl, cycloalkyl, aryl, alkaryl, or aralkyl group, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, cyclooctyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl, phenyl, benzyl, dimethylphenyl, ethylphenyl, etc.
When mixtures of vanadium compounds are employed, the vanadium component may be a mixture of two or more compounds !l - 1! -14-3~36 1~
~ I ~
I correspondir)g to either of the g~neral formulas given abovc I or a mixture of one or more compounds corresponding to one of I those ~cneral formulas with one or more compounds ~j corresponding to the o~her of thosè general formulas.
Ordinarily, when a vanadiun~ compound of the il (RO)nVOX3 n type is employed, it is preferably a compound ¦l wherein X is Cl, becauseAthe greater avai:Lability of such compounds; and it is preferably a monoalkoxy compound, since all other factors being constant, the use of VOC13 or il VOBr3 in the preparation of the catalyst compositions of the il invention does not permit the attainment of-~-narrow a molecular weight distribution as can be obtained when the ¦¦ polymerization reactions of the invention are conducted ln i the presence of the catalyst compositions that are prepared by the use of the hydrocarbyloxy derivatives of VOC13 or ! VOBr3 and ~2) the use of hydrocarbyloxy derivatives other than the monocllkoxy compounds docs not appear to oEfe~r advantages that would compensate for the greater difficulty and cost of obtaining them. Thus, considering both cost and effectiveness in the practice of the invention, the preferred (RO)nVOX3_n compounds are those compounds in which R is ¦alkyl, X is C1, and n has a value of abou-t 1.
Ordinarily, when a vanadium compound of the !! ~RO)mVX4 m type is employed, it is preferably VC14 or a derivative thereof, most preferably VC14 itself. The use of ! VC14 in the preparation of catalyst composltions of the ¦invention leads to the Eormation of compositions which are so ¦satisfactory in the production of injection molding-grade ¦¦ethylene polymers that there is seldom any reason to use a ¦¦more expensive (RO)mVX4 m compound instead of it.
l~ The amount of vanadium compound(s) employed in the ¦¦practice of the invention may be varied considerably but is generally such as to provide at least about 0.001 mol of l;vanadium compound per mol of organometallic compound. When ¦¦the catalyst composition is to be prepared by the preferred .". . . j~ -15-1~3~3636 ll proc~ss described below, wherein no washing step is utilized 1, during or after preparation of the compositions, the amount of vanadium compound employed should not be substantially in ,j excess of the amount capable of reacting with the treated support, i.e., about 1 mol of vanadium compound per mol of organometallic compound. Use of a greater amount would serve no practical purpose and could be disadvantageous in that the excess vanadium compound could lead to fouling of the polymerization reactor. However, a larger amount of vanadium compound may be employed when fouling of the reac~or is not expected to be a problem and/or excess vanadium compound will be removed from the catalyst composition before the composition is used. In the practice of the invention, the amount of vanadium compound employed is generally not in exce55 o about 3 mols per mol of organomet~,lLic co~pound, and excellent results are ob~ained by the use o about 0.03 to 0.2 mol of vanadium compound per mol of organometallic compound, i.e. about 5 to 30 mols of organometallic compound per mol of vanadium compound.
As indicated above, the alcohol empl~yed in preparing the present catalyst co~lpositioTl~ may ~ any alcohol containing 1 to 18 carbon atoms; and it may be conveniently defined as a compound corresponding to the formula ROH, wherein R may be any of the groups, or types oE
groups, mentioned above as exemplary of the R groups of the utilizable hydrocarbyloxy compounds.
When the vanadium compound, or one of the vanadium compounds, emyloyed in the practice of tlle invention is a hydrocarbyloxyvanadium compound that the catalyst manufacturer will synthesize for that use, i~ is frequently desirable, as a matter of convenience, to`employ an alcohol com~onent indenticaI to the alcohol required to synthesize the desired hydrocarbyloxyvanadium compound. However, it is not necessary for the R group of the alcohol to correspond to the R group of any hydrocarbyloxyvanad1um compound being used ll 1l -16-j3'3''3~i ~:
~ I to prep~e th~ catalyst composition; and, in fact, , r / ¦ correspondence of the R groups could be undesirable in some ~¦ ins-tances.
I For example, if a practitioner of the invention ~! warlted to use ethoxyvanadium oxydichloride as his vanadium ,! cornpound but also wanted to prepare a catalyst composition il that would provide the narrowest possible molecular weight ;
distribution in polymers formed in its presence, it would be l more desirable for him to use a long chain alcohol, rather i than ethanol, as the alcohol, because all other factors being ¦ constant, the molecular weight distribution is narrowed as , the chain length of the alcohol is increased. Increasing the chain length of the hydrocarbyloxy group tends to narrow the molecular weight distribution.
The preferred alcohols are primary alcohols, with ~n-alkanols containing 6 to 18 carbon atoms b~ing partlcularly preferred.
The amount of alcohol used in preparing the ¦catalyst composition of the invention should be at least ~l ¦about 0.1 mol per mol of organometallic compound employed.
IThere is no maximum amount of alcohol that may be utilized, jbut its beneficlal effects begin decreasing when an optimum amount is exceeded, so it is generally not used in excess of 10 mols per mol of organometallic compound. Ordinarily, the ~amount of alcohol u-tilized in the practice oE the invention is in the range of about 0.2 to 3, preferably about 0.3 to 1, ~!most preferably about 0.35 to 0.7, mols per mol of ¦¦organometallic compound.
As indicated above, the catalyst compositlons of the invention are prepared by drying the inorganic oxide, reacting the dried inorganic oxide with the organometallic compound, and reacting the thus-treated support with the ! vanadium co~pound, and then reacting that reaction product ~! with the alcohol. The conditions under which -the inorganic oxide is dried are not critical as long as they are adequate Il ll ., i`l ~ 17-i3'3'36 to provide an inorganic oxide that has surface hydroxyl groups alld is substantlally free of adsorbed water. ~lowever, it is ordinarily preferred to dry the inorganic oxide at about 100 to 1000 C., with or without a nitrogen or other inert gas purge, until substantially all adsorbed water is removed. Also, although improved results are obtained by the use of the catalyst compositions of the invention, regardless of the particular temperature at which the inorganic oxide is dried, the drying temperature has been found -to have a negligible-to-noticeable effect on those results - optimum results generally being obtained when the inorganic oxide has been dried at about 200-600 C., but drying tempera-tures of about 500-600 C. generally being required for optimum results when the inorg~nic oxide is alumina. The time required for drying oE t!le inorganic oxide varies, oE course, with the particular ~ryiny temperature used but is usually in the range of about 5-16 hours.
When the inorganic oxide has been substantially freed of adsorbed water, its surface hydroxyl groups may be reacted with the organometallic compound in any suitable manner, conveniently by (1) adjusting its temperature, if necessary, to the temperature at which the reaction with the organometallic compound is to be conducted, (2) slurrying it in an inert liquid hydrocarbon, generally a C4-C8 hydrocarbon, such as isobutane, pentane, lsopen~ane, hexane, cyclohexane, heptane, isooctane, etc., and mixtures thereof with one another and/or with other materials commonly present in commercial distillation cuts having the desired boiling range, (3) adding a substantlally stoichiometric amount of the organometallic compound in neat or solution form, and ~4) maintaining the organometallic compound in intimate contact ¦with the inorganic oxide, e.g., by agitating the slurry, for a time sufficient to ensure substantially complete reaction with the a~ai].able hydroxyl group:, gen:r:lly at least about 39'~6
Fukuda et al. also teach t~_~ethylene copolymers or terpolymers having narrow molecular weight distribution~ can be obtained by the use of an unsupported catalyst composition prepared by ~l~ mixing an alcohol containing l to 12 carbon atoms with VOC13 and then (2) mixing the mixture thus obtained with an alkylalwninum compQund in the presence of the monomers to be interpolymerized, and there are other patents, e.g., Stamicarbon's British Pat. No. 1,175,593 and U.S. Pat. Nos 3,535,269 (Tanaka e-t al.) 4,071,674 (Kashiwa et al.) and 4,~56,865 (Hyde et al.) which teach the use of catalyst compositions prepared by adding an alcohol at some stage during the catalyst preparation. However, although some of these patents are concerned with the production o~
polymers having narrow molecular weight distributions, none of them teaches a catalyst composition which ~ ~e~ the aforementioned need for a catalyst suitable for use in a commercially-attractive gas-phase polymerization process that is capable of producing injeCtion molding-grade polymers having a good alance cf physical prcperties.
i3'~3~3~i n object of the invention is to provide an il economical commercial polymerization process for preparinc3 ¦l ethylene polymers having narrow-to-intermediate molecular ¦l weight distributioll and a good balance of physical ~¦ properties.
¦ Another object is to provide non-fouling catalyst j compositions which are useful in an economical gas-phase ¦ process for polymerizing one or more monomers comprising . ethylene to polymers having a narrow-to-intermediate : ~ molecular weight distribution and a good balance of physical I properties.
¦ The foregoing objects of this invention are broadly ¦ accomplished by providing a process of polymerizing a monomer ¦ charge in~luding cthylene comprising the steps oE:
(a) drying an inorganic oxide having surface : hydroxyl groups to form a support that is substantially free of adsorbed water;
::: `\
~ ~b) reacting the surface hydroxyl groups of the :~: ; support with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the : I formula RXMR'yR"z, wherein M is a metal of Group III of the periodic table, R lS alkyl yroup containing 1 to 12 carbon atoms, R' and R" are independently selected from the group consisting of :~ jj H, Cl, and alkyl and alkoxy groups containing 1 to ; :il I2 carbon atoms, x has a value of 1 to 3, and y and z both represent values of O to 2, the sum of which .
l is not greater than 3-x;
,: 11 ':
(c) reacting the thus-treated support with at l~ least about 0.001 mol, per mol of ,j organometallic compound, of at least one vanadium I' ' I -8-~ij39'16 1 1~
/ I compound corresporlding to a formula sel~cted Erom .
! (RO) VOX3 and (RO)mVX4 m~ in which formulas R .
¦ rcyrescl~ts ~ Cl-C18 monovalent hydrocarbon radical j that is free of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4; .
Il (d) reacting the product of step (c) with at least ¦ about 0.1 mol, per mol of organometallic compound, ::i of an alcohol containing 1 to 18 carbon atoms;
ll (e) feeding the product of step ld) into a Il gas-phase reaction zone;
I! (~) Eeedillq, separc~t~ly and independerltly o said feedincJ step (e), a tr:ialkyl~luminum into the ¦ gas-phase reaction zone in order to form a bed in ¦ the gas-phase reaction zone which comprlses the product of step (d) and the trialkylaluminum;
(g) fluidizing the bed of step (f) at a pressure ¦ of between about 0.7 and 4.2 MPa and a temperature of between about 50 to 120 C. by difEusin~
underneath the bed of step (f) a gas mixture ¦ comprising ethylene, hydro~en, and chloroform at a ¦ rate sufficient enough to give a linear ~as jj velocity in the bed of step (f) of between about 15 I to 60 cm/sec;
¦l (h) removing particulate polymerized substantially Ill et ~ylene particles from the reactlon zone~ aDd il (i) recycling unreacted gas mixture of step (g) from the top of the reaction zone to the bottom of i,¦ the reaction zone.
Il .
i2~3~'3~3~i This invention is a novel process oE polymerizing a monomer charge having ethylene. An inorganic oxide with surface hydroxyl groups is dried to form a support that is substantially free of adsorbed water. The surface hydroxyl groups of the support are reacted with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the formula RXMR'yR'' , wherein M is a metal of Group III of the periodic table, R is an alkyl group containing 1 to 12 carbon atoms, R' and ~" are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x. The thus-treated support is reacted with at least about 0.001 mol, pcr mol oE organometallic compourld, of at least one vanadium compound corresponding to a Eormula selected from (RO)nVOX3 and (RO)mVX4 m~ in which formulas R
represents a Cl-C18 monovalent hydrocarbon radical that is r~e of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value oE 0 to 4. This product is reacted with at least about 0.1 mol, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms, in order to form a catalyst product. The catalyst product is fed into a gas-phase reaction zone.
Separately and independently of thic feeding, a trialkylaluminum is fed into the gas-phase reaction zone in order to forrn a bed in the gas-phase reaction zone which includes inter alia the catalyst product and the trialkylaluminum. The bed is fluidized at a pressure of between about 0.7 and 4.2 MPa and a temperature of between about 50 to 120 C by diffusing underneath the bed including the catalyst product and trialkylaluminum a gas mixturc comprising ethylene, hydrogen, and chloroform a~ a r~-itc 5ufficient enough to give a lil~ear gas velocity in ~*~
comprising catalyst product and trialkylaluminum of betwcen ~, il -10- 1 ~ i399~; i about 15 to 60 cm/sec. Particulate polymerized substantially ethylen~ particles arc relTloved from the reaction zone, and unreacted gas mixture of ethylene, hydrogen and chloroform is recycled from the top of the reaction zone to the bottom of the reaction zone.
The inorganic oxide used in preparing catalyst composition of the inven-tion may be any particulate inor~anic oxide or mixed oxide, e.g., silica, alumina, silica-alumina, magnesia, ~irconia, thoria, titania, etc., having surface hydroxyl groups capable of reacting with the organometallic compound. However, it is generally an inorganic oxide selected from the group consisting of silica, alumina, magnesia and mixtures thereof, i.e., physical mixtures, such as mlxt~res of silica and alumina particles, ctc., and/or chemical mixtures, ~ucll as magnesum silicate, aluminum silicate, etc. 'rhe surface hydroxy~ groups may be at the ou-ter surface of the oxide particles or at the surfaces of pores in the particles, the only requirement in this regard being that they be available for reaction with the organometallic compound.
The specific particle size, surface area, pore volume, and number of surface hydroxyl groups characteristic of the inorganic oxide are not critical to its utility in the practice of the ïnvention. However, since such characteristics determine the amount of inorganic oxide that it is desirable to employ in preparing the catalyst compositions, as well as sometimes affecting the properties of polymers formed with the aid of the catalyst compositions, these characteristics must Erequently be taken into consideration in choosing an lnoryanic oxide for use in a par-ticular aspect of the invention. For exampler when the catalyst composition is to be used in a gas-phase polymerization process - a type of process in wh:ich it is known that the polymer particle size can be varied by varying 1~3'3~36 l the particle size of the support - the inorganic oxide used in preparing the catalyst cornposition should be one having a particle size that is suitable for the production of a polymer having the desired particle size. In general, optimum results are usually obtained by the use~of inorganic oxides having an average particle size in the range of about 30 to 600 microns, preferably about 30 to lOG ~icrons; a surface area of about 50 to 1000 square meters per gram, ¦
preferably about 100 to 400 square meters per gram; and a pore volume of about 0.5 to 3.5 cc per gram, preferably about 0.5 to 2 cc per gram.
As indicated above, the organometallic compound that is reacted with the surface hydroxyl groups of the inorganic oxide in the practice of the invention may be any one or more organometallic compounds corresponding to the formula RXMR'yR"z, wherein M is ~ metal o~ Group III of the pel-iodic tabl~, R is an alkyl group containing 1 to 12 carbon atoms, R' and R" are independently selec~ed from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z both represent values of 0 to 2, the sum of which is not greater than 3-x. Thus, M may be, e~g. aluminum, gallium, indium, or thallium; R may be, e.g., methyl, ethyl, propyl, isopropyl, n-butyl, n-pentyl, isopentyl, t-pentyl, hexyl, 2-methylpentyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, dodecyl, etc; R', when present, may be H, Cl, an alkyl group, such as one of those exemplified above for R, which is the same as or different from R, or an alkoxy group, such as the alkoxy groups corresponding to the aformentioned alkyl groups; and R", when present, may be any of the substituents mentioned above as exemplary of R' and may be the same as or different from R'.
The preferred organometallic compounds are those in which M is aluminum. Utilizable aluminum compounds include chlorides, such as dimethylaluminum chloride, diethylaluminum 2~j3~3~i chloride, dipropylal~mi~um chloride, diisobutylalumir-um chloride, the corresponding alkylalurninum dichlorides, etc., and mixtures of such chlorides, but the chloridcs are generally not particularly preferred because of the halogen residue they contribute to polymers made in -their presence.
The more preferred aluminum co~pounds are the trialkylaluminums, dialkylaluminum hydrides, dialkylalumlnum alkoxides, and alkylaluminum dialkoxides, such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, isoprenylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, trldodecylaluminum, etc.; the correspondinq alkoxy compounds wherein one or two of the alkyl groups have been replaced by alkoxy groups, such as ethylalumlnum diethoxide, dicthylalumirl~lm ethoxide, ethylalum.inum scs~uLethoxide, ethylaluminum diisopropoxide, etc.; diethylalumin-lm hydride, di-n-propylaluminum hydride, diisobutylaluminum hydride, etc.; and mixtures of such compounds.
Especially preferred aluminum compounds are the trialkylaluminums, particularly triethylaluminum and ¦tri-n-hexylaluminum, which are advantageous to employ because of their cost, availability, and/or efEectiveness. When a trialkylaluminum is used as the organometallic compound, it is generally found that - all other factors being constant -the molecular weight distribution of polymers prepared with the catalysts of the invention are narrowed as the chain lengths of the alkyl groups of the trialkylaluminum are lengthened.
The amount of organometallic compound employed is ¦¦at least substantially the stoichiometric amount, i.e., the ¦¦amount required to react with all of the available hydroxyl groups on the inorgarlic oxide. Use of an amount'less than the substantially stoichiometric amount would broaden the molecular weight distributions of polymers formed in -the l¦presence of the catalyst compositions; use of an amount !1, 1~ -13-3t36 ;i greater th~n the substantlally stoichiometic amount is permissable within the scope of the invention but frequently serves no practical purpose and can be disadvantageous in that the excess organometallic compound sometimes leads to fouling of the polymerization reactox if not removed from the catalyst composition prior to the composition's being used. ¦
When the number of available hydroxyl groups on the particular inorganic oxide being treated is not known, it can be determined by any conventional technique, e.g., by reacting an aliquot of the inorganic oxide with excess triethylaluminum and determining the amount of evolved ethane. Once the number of available hydroxyl groups on the inor~anic oxide is known, the amount of or~anometallic compound to be ernployed is chosen ~o a3 to prov:ide at lcast about one mol oE orcJanometall.ic compound per mol o~ availabLe hydroxyl groups.
The vanadium component of the catalyst compositions of the invention may be any one or more compounds corresponding to a formula selected from (RO)nVOX3 ~ and (RO)mVX4 m~ wherein R represents a monovalent hydrocarbon radical that contains 1 to 18 carbon atoms and is free of aliphatic unsaturation, X is C1 or Br, n has a value o 0 to 3, and m has a value of 0 to 4. Thus, the utilizable vanadium compounds include VOC13, VOBr3, and the indicated mono-, di-, and trihydrocarbyloxy derivatives thereof, as well as VC14, VBr4, and the indicated mono-, di-,. tri-, and tetrahydrocarbyloxy derivatives thereof; and R, when present, may be a straight- or branched-chain alkyl, cycloalkyl, aryl, alkaryl, or aralkyl group, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, hexyl, cyclohexyl, heptyl, octyl, cyclooctyl, nonyl, decyl, dodecyl, hexadecyl, octadecyl, phenyl, benzyl, dimethylphenyl, ethylphenyl, etc.
When mixtures of vanadium compounds are employed, the vanadium component may be a mixture of two or more compounds !l - 1! -14-3~36 1~
~ I ~
I correspondir)g to either of the g~neral formulas given abovc I or a mixture of one or more compounds corresponding to one of I those ~cneral formulas with one or more compounds ~j corresponding to the o~her of thosè general formulas.
Ordinarily, when a vanadiun~ compound of the il (RO)nVOX3 n type is employed, it is preferably a compound ¦l wherein X is Cl, becauseAthe greater avai:Lability of such compounds; and it is preferably a monoalkoxy compound, since all other factors being constant, the use of VOC13 or il VOBr3 in the preparation of the catalyst compositions of the il invention does not permit the attainment of-~-narrow a molecular weight distribution as can be obtained when the ¦¦ polymerization reactions of the invention are conducted ln i the presence of the catalyst compositions that are prepared by the use of the hydrocarbyloxy derivatives of VOC13 or ! VOBr3 and ~2) the use of hydrocarbyloxy derivatives other than the monocllkoxy compounds docs not appear to oEfe~r advantages that would compensate for the greater difficulty and cost of obtaining them. Thus, considering both cost and effectiveness in the practice of the invention, the preferred (RO)nVOX3_n compounds are those compounds in which R is ¦alkyl, X is C1, and n has a value of abou-t 1.
Ordinarily, when a vanadium compound of the !! ~RO)mVX4 m type is employed, it is preferably VC14 or a derivative thereof, most preferably VC14 itself. The use of ! VC14 in the preparation of catalyst composltions of the ¦invention leads to the Eormation of compositions which are so ¦satisfactory in the production of injection molding-grade ¦¦ethylene polymers that there is seldom any reason to use a ¦¦more expensive (RO)mVX4 m compound instead of it.
l~ The amount of vanadium compound(s) employed in the ¦¦practice of the invention may be varied considerably but is generally such as to provide at least about 0.001 mol of l;vanadium compound per mol of organometallic compound. When ¦¦the catalyst composition is to be prepared by the preferred .". . . j~ -15-1~3~3636 ll proc~ss described below, wherein no washing step is utilized 1, during or after preparation of the compositions, the amount of vanadium compound employed should not be substantially in ,j excess of the amount capable of reacting with the treated support, i.e., about 1 mol of vanadium compound per mol of organometallic compound. Use of a greater amount would serve no practical purpose and could be disadvantageous in that the excess vanadium compound could lead to fouling of the polymerization reactor. However, a larger amount of vanadium compound may be employed when fouling of the reac~or is not expected to be a problem and/or excess vanadium compound will be removed from the catalyst composition before the composition is used. In the practice of the invention, the amount of vanadium compound employed is generally not in exce55 o about 3 mols per mol of organomet~,lLic co~pound, and excellent results are ob~ained by the use o about 0.03 to 0.2 mol of vanadium compound per mol of organometallic compound, i.e. about 5 to 30 mols of organometallic compound per mol of vanadium compound.
As indicated above, the alcohol empl~yed in preparing the present catalyst co~lpositioTl~ may ~ any alcohol containing 1 to 18 carbon atoms; and it may be conveniently defined as a compound corresponding to the formula ROH, wherein R may be any of the groups, or types oE
groups, mentioned above as exemplary of the R groups of the utilizable hydrocarbyloxy compounds.
When the vanadium compound, or one of the vanadium compounds, emyloyed in the practice of tlle invention is a hydrocarbyloxyvanadium compound that the catalyst manufacturer will synthesize for that use, i~ is frequently desirable, as a matter of convenience, to`employ an alcohol com~onent indenticaI to the alcohol required to synthesize the desired hydrocarbyloxyvanadium compound. However, it is not necessary for the R group of the alcohol to correspond to the R group of any hydrocarbyloxyvanad1um compound being used ll 1l -16-j3'3''3~i ~:
~ I to prep~e th~ catalyst composition; and, in fact, , r / ¦ correspondence of the R groups could be undesirable in some ~¦ ins-tances.
I For example, if a practitioner of the invention ~! warlted to use ethoxyvanadium oxydichloride as his vanadium ,! cornpound but also wanted to prepare a catalyst composition il that would provide the narrowest possible molecular weight ;
distribution in polymers formed in its presence, it would be l more desirable for him to use a long chain alcohol, rather i than ethanol, as the alcohol, because all other factors being ¦ constant, the molecular weight distribution is narrowed as , the chain length of the alcohol is increased. Increasing the chain length of the hydrocarbyloxy group tends to narrow the molecular weight distribution.
The preferred alcohols are primary alcohols, with ~n-alkanols containing 6 to 18 carbon atoms b~ing partlcularly preferred.
The amount of alcohol used in preparing the ¦catalyst composition of the invention should be at least ~l ¦about 0.1 mol per mol of organometallic compound employed.
IThere is no maximum amount of alcohol that may be utilized, jbut its beneficlal effects begin decreasing when an optimum amount is exceeded, so it is generally not used in excess of 10 mols per mol of organometallic compound. Ordinarily, the ~amount of alcohol u-tilized in the practice oE the invention is in the range of about 0.2 to 3, preferably about 0.3 to 1, ~!most preferably about 0.35 to 0.7, mols per mol of ¦¦organometallic compound.
As indicated above, the catalyst compositlons of the invention are prepared by drying the inorganic oxide, reacting the dried inorganic oxide with the organometallic compound, and reacting the thus-treated support with the ! vanadium co~pound, and then reacting that reaction product ~! with the alcohol. The conditions under which -the inorganic oxide is dried are not critical as long as they are adequate Il ll ., i`l ~ 17-i3'3'36 to provide an inorganic oxide that has surface hydroxyl groups alld is substantlally free of adsorbed water. ~lowever, it is ordinarily preferred to dry the inorganic oxide at about 100 to 1000 C., with or without a nitrogen or other inert gas purge, until substantially all adsorbed water is removed. Also, although improved results are obtained by the use of the catalyst compositions of the invention, regardless of the particular temperature at which the inorganic oxide is dried, the drying temperature has been found -to have a negligible-to-noticeable effect on those results - optimum results generally being obtained when the inorganic oxide has been dried at about 200-600 C., but drying tempera-tures of about 500-600 C. generally being required for optimum results when the inorg~nic oxide is alumina. The time required for drying oE t!le inorganic oxide varies, oE course, with the particular ~ryiny temperature used but is usually in the range of about 5-16 hours.
When the inorganic oxide has been substantially freed of adsorbed water, its surface hydroxyl groups may be reacted with the organometallic compound in any suitable manner, conveniently by (1) adjusting its temperature, if necessary, to the temperature at which the reaction with the organometallic compound is to be conducted, (2) slurrying it in an inert liquid hydrocarbon, generally a C4-C8 hydrocarbon, such as isobutane, pentane, lsopen~ane, hexane, cyclohexane, heptane, isooctane, etc., and mixtures thereof with one another and/or with other materials commonly present in commercial distillation cuts having the desired boiling range, (3) adding a substantlally stoichiometric amount of the organometallic compound in neat or solution form, and ~4) maintaining the organometallic compound in intimate contact ¦with the inorganic oxide, e.g., by agitating the slurry, for a time sufficient to ensure substantially complete reaction with the a~ai].able hydroxyl group:, gen:r:lly at least about 39'~6
5 minutes. The reaction may be conducted with or without pres-sure and at ambient or reflux temperatures, depending on the particular organometallic compound employed, as will be readily understood by those skilled in the art. When the or~anometallic compound is added in solution form; it is generally preferred, through not required, that the solvent be the same inert li~uid hydrocarbon as is already present in the slurry.
The reaction of the vanadium component with the treated support may also be accomplished by conventional means, such as any of the techniques described in British Patent ~o. 1,489,410.
However, it is st desirably accomplished simply by adding the vanadium compound in neat or solution form to the slurry of treated support and maintaining it in intimate contact with the treated support for a time sufficient to provide for substantial-ly complete reaction, usually at least about 5 mlnutes and preferably about 10-60 minutes, although, actually, the reaction is virtually instantaneous.
When reaction of the vanadium component with the treated support has been completed, reaction with the alcohol may be accomplished in any suitable manner, conveniently just by adding the alcohol to the vanadium component/treated support reaction product and maintaining it in contact therewith, e.g., by agitating the slurry, for a time sufficient to ensure sub-stantial completion of the desired reaction, usually at least about 5 minutes and most commonly about 30-60 minutes. All that is critical about the manner in which the alcohol is reacted with the other catalyst components is the time at which it is added to the system. Reaction of the other components with one another must be substantially complete before the alcohol is ~: 30 added in order Eor the catalyst compositions to have the desired performance capabilities.
~' ,. .~,~
39~ 1 /~ I
fter the alcohol has b~en reacted with the othcr c~talyst compone~ts, the resultant catalyst composition may or may not require further treatment to make it suitable for use, depending on the particular process that has been used to prepare the catalyst composition and the particular type of polymerization process in which it is to be used. For example, if the catalyst composition has been prepared by a type of process which results in its being already dry when reaction with the alcohol has been accomplished, no further treatment is likely to be necessary if the composition is to be used in a gas-phase polymerization process; but slurrying of the composition in a suitable liquid medium may be desirable if it is to be used in a slurry or solution polymerization process. On the other hand, if the catalyst composition has been prepared by the preferred process described ~bove, i.e., if the inorgar-ic oxide has been slurried in a liquid medium prior to the addition of the other components, it is already suitable for use in a slurry or solution polymerization process but will have to be dried to make it suitable for use in a gas-phase polymerization process. When the composition is to be dried, i.e., freed of any liquid medium used in its preparation, the drying may be achieved by any conventional technique, e.g., filtration, certrifugation, evaporation, blo~ing with nitrogen, etc.
Commerical preparation of the catalyst of this invention is preferably carried out as taught by Rogers in U.S. Patent No.
4,426,317.
Regardless of the particular techni~ue used to prepare the catalyst compositions of the invention, it should be kept in mind that~they are Ziegler catalysts and are therefore susceptible to poisoning by the materials, such as oxygen, water, etc., that are known -to reduce or des-troy the effectiveness of Ziegler catalysts. A~cordingly, they should be prepared, stored, and used under conditions that will !
,, ij ~o ~,3~3~36 permit them to be useful as polymerization catalysts, e.g., by the use of an inert gas atmosphere, such as nitrogen.
~ he invention is particularly advantageous in that it provides catalyst compositions which (1) have the active in-gredients chemically-attached to an inorganic oxide support, (2) are capable of producing ethylene polymers having a narrow-to-intermediate molecular weight distribution, as desired, and a good balance of physical properties by an economical gas-phase process that gives a high yield of polymer and ~3) do not foul 1~ gas-phase reactors. The fact that high yields of polymer can be obtained by the use of the catalyst compositions is particu:Larly unexpected in that these high yields are attalnable even when the catalyst compositions a.re prepared b~ th~ preferrecl p.rocess whe.rein no washing step is required or utilized during or after preparation of the compositions. Both experience in the field and the teachings of the prior art indicate that at least one washing step should be required in the preparation of such com-positions when high yield catalysts are desired.
After the catalyst composition of this invention is prepared, it is subseqNently introduced into a gas-phase fluid-ized reactor similar to that taught by Miller in United States Patent No. 4,003,712. In a preferred embodiment of the invention, the diameter of the velocity reduction or disengaging zone at the top of Miller's reactor is enlarged and the cyclone and filter in the gas recycle system are eliminated for stable, long-term commercial operation. It should be understood that polymeriza-tion with the catalyst compositions o this invention may be conducted in any fluidized system which has a distribu~ion plate means and allows a monomer gas to fluidize a bed including the catalyst compositions; allows unreacted monomer gas to be re-recycled fr.om the top of the fluidized system back to the bottom of the fluidized system :! 21 3~3~
/ li or for admixing with thc monomcr gas prior to its diffusing / or passing thro~yh the fluid.ized bed; allows a polymer / !I product to be withdrawn from the fluidized bed; allows i catalyst and a trial~ylaluminum to be added to the fluidized bed; and provides for the removal of the heat of polymerization. Size, shape, pressure rating, heat removal i¦ capability, and other factors can limit the polymer production capacity of the gas-phase fluidized-bed reaction Il systems of this invention. The process of this invention may ¦I be practiced in commercial facilities having production ¦ capacities of 50,0~0 to 250,000 metric tons per year or more.
The process of this invention may also be practiced in laboratory scale reactors having a production capacity of from about 0.1 to 1.0 kg/hr or in pilot p:Lant reactors having ¦ p.rocluctlon capac.i~i~s oE Erom S to 5Q0 Ic~/hr.
¦ ~'h~ c~talyst compositions oE ttliS lnvelltLon should preferably be injected or Eed to the fluidized bed system at a point between the distribution plate and about 7/8 o~ the height of the catalyst bed from the distribution plate of the ! reactor. More preferably, the catalyst compositions are fed il into the fluidized bed system at a point of between about 1/8 ¦ to about 1/2 of. the heigh-t of the fluidized bed. Injection ! of the catalyst composition above about 1/8 of the height of the bed (as opposed to below 1/8 of the height) offers distribution of the catalyst composition throughout the ¦ entire ongoing fluidized bed to retard and/or preclude the 1~ formation of localized spots of high catalyst composition ¦¦ concentration which would result in the formation of "hot ¦¦ spots" at or near thc distri.bution plate~ A "hot spot" is a ¦¦ localized region ln which the~exothermic heat of .
polymerization is not dissipated before some polymer h~ to ¦¦ the softening point of the polymer. Any introduction of -the ~ 4~1yS~
`! ~ t~ t~ compositions o-f this invention at a point above i about 7/8 of the height of the fluidized bed frotn the distribution plate of -the reactor rnay lead to excessive ¦ carryover of the fresh catalyst of this invention into the ~ ,2-39~36 gas recycle system. The rate of injection or rate of feed of the catalyst composition of this invention is any suitable rate which is equal to catalyst consumption in the polymerization process of this invention and generally depends on the size of the fluidized bed system. The rate of production of the particulate polymerized substantially ethylene particles in the fluidized bed is partly determined by the rate of catalyst injection. We have found that the rate of injection of the catalyst for our polymerization i~
process is generally preferably at a rate that maintains the concentration of the vanadium in the fluidized bed between about 1/10 ppm to about 50 ppm based on weight of vanadium metal divided by total solids in the bed. More preferably, the rate of injec:tion oE the catalyst is that which would maintaln the concentrakion Oe the vanadium .in thc ~luldlæed bed between about 0.50 ppm to about 10 ppm; most preferably, between about 1 ppm to about 4 ppm. The fluidized bed is substantially particulate polymerized ethylene polymer particles formed by polymerization of the monomer~s) on the catalyst compositions of this invention.
In order for the catalyst composition of this invention to give high yield of polymer product per unit of vanadium component, we have discovered that it is necessary to add or inject at least one trialkylaluminum compound into the fluidized bed system as a co-catalysts. For a variety of reasons, it is preferred to add the trialkylaluminum compound, or the mixture of trialkylaluminum compounds, that i5 being used as a co-catalyst directly to the fluidized bed il separately and independently of the catalyst and at an injection point removed from the catalyst injection point.
However, the process of this invention does not depend on the method of feeding the trialkylaluminum co-catalyst or the location of its injection point. The trialkylaluminum compounds of this invention may be fed to the f luidized bed as pur~ compounds, or in solution in a liquid hydrocarbon which will vaporize in the fluidized bed. Suitable ~ ~i399~:i ~
hydrocarbon solvents include, but are not limited to, isobutane, isopentane, hexane, heptane and mixtures ~hereof.
The trialkylaluminum oE ~his in~ention snay be any trialkylaluminum wherein the alkyl or combination of alkyl groups contain between 1 and about 36 carbon atoms. In a preferred embodiment of the invention, the alkyl group or combination of alkyl groups contain between 1 and about 12 carbon atoms. Suitable trialkylaluminum compounds have been found to lnclude trimethyl-, triethyl,- tri-i-butyl-, tri-n-hexyl-, tri-n-octyl- and ethyl di-i-butylaluminum. It should be understood that trialkylaluminum compounds add ethylene, and alpha olefins to some extent, under the operating temperatures ~lld pressures o~ the polymerization process of ttle invention. rrhus, an ethyl group on alum.irluln may he inserted by ethylelle to become~ a butyl group, etc.
Therefore, there is no reason to believe or require that all alkyl groups on the aluminum be -the same. There is every reason to believe that mixtures of trialkylaluminum compounds are generated during polymerization and are as effective as pure compounds. Since the exact composition of the alkyl groups on aluminum during the polymerization process of this invention is not known because of the ethylene insertion reaction, all of the -trialkylaluminum species in the fluidized bed are referred to collectively Eor the purposes herein as "trialkylaluminum".
As was the case for the catalyst composition of this invention, the rate of injection of the trialkylaluminum is also any suitable rate which is equal to the trialkylaluminum consumption in the polymerization process, and also depends on the size of the fluidized bed system. Polymer productivity from the polymerization process is not only determined by the rate of catalyst injection, but also from the rate of trialkylaluminum injection.
~ ;39~36 Assuming that the trialkylaluminum compounds of this inventionremain in the fluidized bed and assuming uniform distribution of trialkylaluminum throughout the fluidized bed, the molar concentration of trialkylaluminum may be calculated from the molar feed rate of the trialkylaluminum being fed into the fluidized bed reaction system and the withdrawal rate of the polymer product particles. Likewise, assuming uniform distribution of the catalyst composition throughout the fluidized bed, the molar concentration of the vanadium component of the catalyst composition may be calculated from the molar feed rate of the vanadium component of the catalyst composition being fed into the fluidi~ed bed reaction system and the withdrawal rate of the polymer product particles. At stable, lined-out operating conditions, the ratio of the molar concentratlon of the trialkylaluminum to the molar concentration o~ the vanadium compon~nt in the hed of catalyst composition will asymptote to the ratio of the molar feed rate of the trialkylaluminum to the molar feed rate of the vanadium components oE the catalyst composition of this invention.
For -the catalyst composition of this invention, the injection rate of the trialkylaluminum should be such that the Al/V
ratio in the ~luidized bed of the molar concentration of the trialkylaluminum to the molar concentration of the vanadium component is between about 1 to about 5,000. We have ~ound that the activity of the catalyst composition of the invention is maximized in a certain range of trialkylaluminum to vanadium molar ratio. Too little or too much trialkylaluminum suppresses the activity of the catalyst composition and the polymer production. It has been determined that a plot of the trialkylaluminum to vanadium molar ratio versus the catalyst (of this invention) activity possesses a generally flat peak and the optimum trialkylaluminum to vanadium molar ratio lies in the range of from about 2 to about 500, with from about 2 to 60 being the most preEerred from the standpoint of m~nimizinq c-talyst / ~ 3~36 / residue levels in the polymer and trialkylaluminum cost.
/ Therefore, the preferred injection rate of the / trialkylaluminum into the fluidized bed system of this / invention is that injection rate whercin the molar ratio in / ¦ the fluidized bed of the molar concentration of the ~I trialkylaluminum to the molar concentration of the vanadium il composition is between about 2 to 500, and most preferably ¦¦ from about 2 to about 60.
¦ The bed of particulate polymerized substantlally I¦ ethylene particles, trialkylaluminum ancl the catalyst ! composition oE this invention has to be fluidized at a l pressure of between about 0.7 and 4.2 MPa and a temperature i of between about 50 to 120 C. Fluidization is conducted by ¦ diffusing underneath the bed (and through the distribution plate) a gas mixture comprising ethylene, hydrogen and chloroform at a reltc sufEicicnt enougll to cJive c~ lineclr gas velocity in the bed oE between about 15 to about 60 cm/sec.
¦ The gas mixture will also include inert gas which is used to ¦ feed the catalyst~ compositions to the fluidized bed. A
majority of the gas mixture is in the form of unreacted gas mixture that is recycled from the top of the reaction zone to l the bottom of the fluidized bed of the reaction zone.
¦¦ Although the catalyst compositions and the ¦I tr:ialkylaluminum of this invention polymerize ethylene and ! other olefins over a wide range of temperatures, there is a ~1 practical limitation to the temperatures at which -the gas-phase fluidized-bed process of this invention is I commercially viable. For example, above about 120 C, ¦ ethylene polymers soften and tend to agglomerate in a ¦ fluidized bed, leading to formation of lumps, loss oE
jj fluidization, and onset of an inoperable condltion. ~elow about 50 C, the production rate of commercial reactors becomes so low that the process is no longer profitable. It , is generally desirable to operate near the highest ! temperature at which the polymer will not agglomerate in thc ~I bed with a temperature safety factor for small temperature A~ 26-~ r~ 3 ~316 u~sets so th~t inoperable conditions are not encountered even brief1y. Tlle~refore, the preferred temperature range is from about ~ C, with the range from about ~ C being most preferred.
The pressure at which the polymerization process of this invention is conducted is selected on the basis of desired commercial operation rather than upon some limitation of the catalyst. The catalysts of this invention will function at atmospheric, subatmospheric, or superatmospheric pressures. For economy of operation, one wishes to polymerize near the highest pressure for which the equipment is designed in order to maximize the production rate for the equipment. But, because commercia1 process equipment generally is rnore expcns.iv~ with the higher pre~ssure, there is a natura1 tencl~llcy to d~sign commercial equipm~ Eor low pressures. Thes~ constraints lead to a commercial operating range of about 0.7 - 4.2 MPa. At the lower pressures, however, higher dwell or residence times in the reactor are required to reach high yields of polymer per unit of ¦catalyst. At the higher pressures, there is little room to safely accommodate pressure upsets. These constraints lead to a preferred pressure range of about 1.6 - 3.9 MPa.
In order to provide sufficient mixing and agitation in the bed of trialkylaluminum and catalyst that "hot spots"
will not develop, it is necessary that the flow rate of -the gas mixture through the bed of polymer particles containing traces of the catalyst and the trialkylaluminum be sufficient to fluidize the particles. For the powdered polymer C~fa ~Ysf' particles produced by the cataly~ compositions of this invention, the minimuln fluidization velocity, Gmf, has been determined to be about 15 cm/sec. As gas velocity increases, a point is reached at which thè particles are largely swept out of the bed by the force of the rising gas ~the transport velocity), which, for the particles of the prese~t invention jjis about 4 Gmf, or 60 cm/sec. To provide some margin for ',1 !1 -27- l ,~.~,i i . Il .
j;3~6 1~
¦!
o~er~tirlg exror, ttle preferred velocity range is about 1.5 -3.0 G~lf, or about 23 - 45 cm/sec, in contrast to the 3 - 5 G~nf range pre~erred by Miller in U.S. Patent No. 4,003,712 ~;
for his catalysts.
The cat~lysts of this invention, under the commercial conditions descri~ed above, in the absenc2 of a chain transfer agent, produce polymer of a molecular weight too high for conventional melt processing. Therefore, in the i commercial practice of this invention the fluidi~ing gas :~¦
mixture must CQntain hydrogen during polymerization to adjust the molecu ar weight ~as determined ùy melt index~ to the ¦
desired range for the product being produced. This is done by increasing the hydrogell/ethylene ratio to raise melt index ;
~lower molecular weight), or reducing the ratio to produce the opposite eEect. The catalyst compositions o~ this invention are sensltive to hydrogell, so lt is yenerally not necessary to use more than 10~ by vol. of hydrogen even -to produce the highest melt index polymer. Furthermore, when used as described herein, altering the hydrogen/ethylene ratio to increase melt index does not cause a loss of production rate in a commercial plant within the range of melt indexes used for commercial polymers at this time.
Preferably, the amount of hydrogen utilized ln a preerred embodiment o~ the invention in order to control the molecular w2ight o the produced polymer is between about 0.10 ~ to about 10.0 % by volume of the total gas mixture volume.
The gas mixture has to have chloroform in order that the catalyst compositions of this invention can have their activity promoted. While o-ther halogenated carbon f,~ o7~r~lch~oro~e~) a~æ
compounds such as methylene chloride and ~3tr~ G~ Om~hamr may work as promoters, from the standpoints of promotion of catalyst activity, cost, availability, ease of handling, and catalyst promotion without causin~ reactor fouling, chloroEorm is clearly the compound oE choice. Only small amounts are needed because of its effectiveness. Uncler the conditions of polymerization, it is a gas, and generally will ~3~ i / ~ be present in the recycle gas at concentrations between about 0.0001 to about 1.000 % by vol of the gas mixture. Since the ¦¦ prefcrred vol ~ ranges for hydrogen and chloroform is ¦¦ r~spectively between about 0.10 and about 10.0 and between il about 0.0001 and about 1.000, the remaining vol % for any given volume of the gas mixture would include ethylene and !¦
,¦ any of the inert gas which is used to feed the catalyst 1i compositions to the fluidized bed in the reaction zone. In a preferred embodiment of the invention, ethylene preferably comprises between about 50.0 vol % and about 99.9 vol % of the gas mixture.
t appears that the molar ratio CHC13/V is more l useful in predicting and understanding its effect than the I overall concentra~ion in the gas, since it afEects the catalyst's per~ormance. The CIIC13/V ratio may vary Erom ! about 2 to about 5000. ~ecause chloroform :is relativcLy nexpensive and used in small amounts, there is no real ¦¦economic incentive to minimize its use. However, there lappears to be a maximum in the curve of catalyst activity vs.
¦ CHC13/V rati~, with a broad optimum in the range of about 10 - 500. There also appears to be an interac-tion between the optima for CHC13/V ratio and A1/V ratio such that lower ¦C~C13/V ratios are generally preferred when the A1/V ratio is Illow, and higher CHC13/V ratios are generally preferred when ¦I the Al/V is high. Other factors, such as impurity levels, ¦jmay also cause a shift in the optimum CHC13/V ratio or A1/V
ratio, but generally such factors will not shift-the optima outside the preferred ranges.
1l We have found that, in order to control the density I ¦of the produced ethylene polymer, the gas mixture of ethylene, hydrogen and chloroform may include alpha olefins ¦which will be copolymerized with the ethylene of the gas limixture. Although the catalyst compositions of this ¦jinvention will copolymerize essentially any alpha olefin with ¦lj ethylene, there is a practical limit to what can be li i39~36 /~1 effectively done in a gas-phase reaction. Generally, olefins havlrlg more than 8 carbon atorns have too low a vapor pressure to be used in high enough concentration to have much effect on density. Propylene, butene-l, hexene-l, 4-methylpentene-1, and octene-l are among the alpha olefins useful in copolymerization with ethylene in this invention.
Preferably, mixtures of alpha olefins having 3 to 8 carbon atoms are used in a preferred embodiment of this invention.
By this process, polymers generally considered to be HDPE
(densities of 0.940 or greater) and LLDPE (densities below 0.940) may be made equally well by adjusting comonomer concentration in the feed or other factors. The amount of ¦~
comonomer needed is determined by the density of the polymer product being made. Generally, no~ less than 0~5 vol ~ of alpha olefin will be used ~ncl not morc than 30 vol ~ Oe th~
alpha olefin will be utllized for any given volu~ne of the gas mixture along with any of the inert gas and between about 0.10 vol % and about 10.Q vol % of hydrogen, between about 0.0001 vol % and about 1.000 vol % chloroform, and between about 50.0 vol ~ and about 99.4 vol ~ ethylene.
The catalyst compositions of this invention are preferably fed to the gas-phase fluidized-bed reactor as~*r~-particulate matter, such as dry powder under the inert gas.
Any gas that does not react with the catalyst is considered inert. Suitable inert gases include nitrogen, argon, and methane. Any dev1ce which can measure and convey a free-flowing powder is suitable for feeding the catalyst, although the device must not allow monomer to enter the catalyst storage are~ of the feed device. Once the catalyst has b~en measured and delivered to the catalyst feed line, any good method of conveying it to the fluidized bed may be used.
These include mechanical means such as screw conveyers, or gas conveying with inert gas or, as Miller teaches, with recycle gas from the reactor. Catalyst may be added continuously, semi-continuously, or discontinuously to the r~actor. Continuous addition is preferred, but ls virtually 1,1 1.~ 3~6 I ilnpossible at laboratory scale. Catalyst may be fed pure or Il may b~ dil~lted with any free-fl~wing particulate material such as pure, dry support or polymer powder from the reactor.
¦ In catalyst feeding, all that is ~eally critical is that the catalyst be fed at a controlled rate and be dispersed in the bed before a "hot spo-t" develops.
¦ The produced particulate polymerized su~stan~ially ethylene particles may be removed from the gas-phase reaction zone by any suitable means and at any suitable location.
Preferably, the produced ethylene polymer particles are removed in accordance with the procedure described by Miller in U. S. Patent No. 4,003,712. In a preferred embodiment of the invention, the producecl ethylene polymer particles are removcd from the gas-phase reaction zone above and in uroximity to tho distrib~ltion pla~e.
~s has been mentioned, it is necessary to ttave good ¦ fluidization, good catalyst ~ixing, and good distribution of ~¦ gas in the bed in order to avoid l'hot spots" which cause ¦ lumps to form in the bed. These lumps themselves disturb ¦¦ fluidization so, once a lump forms, the tendancy for other ¦¦ lumps to form is enhanced. Eventually a reactor shut down is ¦necessary because the process becomes inoperable.
Similarly, i-t is necessary for long-term, stable ¦operation of commercial reactors that the surfaces of the ¦reactor and distribution plate remain clean. If a polymer coating (fouling) builds up on a reactor surface, several ¦undesirable things may happen. First, fouling on the ¦Idistribution plate tends t~ perturb the desired gas ~,distribution and restrict the abilitytxJ~the poly~er ¦¦par-ticles at the plate to ~ove laterally. Both effects tend !Ito produce "hot spots" at or near the distribution plate.
¦!Second, fouling on the reactor wall inhibits the normal ¦¦downward motion oE fluidized part-cles at the wall surface.
¦IParticles which "hallg up" at a wall surface can ~Jenexate "hot 'spots". Third, the wall coating may come loose in places, I
.
il -31-- ~,rl,' /~ ~L2~39~6 fall into the bed, and disrupt fluidization as any lump would do. Even worse, wall fouling usually is in the form of a "slleet" rather than a lump, and produces severe gas channelling in the bed if it falls off.
Although poor selection of operating conditions or poor operating techniques may lead -to lump formation, it appears that fouling of reactor surfaces depends primarily on j the catalyst used. Some catalysts tend to produce J
rouling,and some do not. At this time, insufficient experience has been gained to be able to predict wi-th r~
accuracy which catalyst compositions will foul and which will give stable operation for months without fouling reactor surfaces. Obviously, for economical commercial operation, the catalyst must not Eoul reactor surfaces. Fouling in a commercial r~clctcr l~a~ls ~o "down time" with consequen~ Loss oE production and ~xtr;l m~int~llance cost for cleaning. Thus, fouling will cause a gas-phase fluidized-bed process to lose its economic advantage over slurry processes.
The following examples are given to illustrate the invention and are not intended as a limitation thereof. In these examples, compositions and processes that are illustrative of the invention are distinguished from those that are outside the scope of the invention and are included only for comparative purposes by using an alphabetic designation for any example or run that is a comparative example and a numeric designation for the examples and runs that are illustrative of the invention. Yields given in the examples are measures of productivity in terms of the number of grams of polymer produced per gram of catalyst per hour, melt indices (MI2)~are those determined by ASTM test D-1238-65T using a 2160-gram weight, while the NVR values are "normalized" melt viscosity ratios determined by measuring the apparent viscosi-ties of the polymers at 30 sec 1 and 300 sec. 1, respectively, at 200 C. in an Instron caplllary rheometer and (2) normalizing them to V30=5 by the equation.
NVR=antilog (0.14699~0.7897 log V30 - log V300) I
i -3~
3~3~3~j l I where v30 and V300 are the measured apparent viscosities.
I This normalization permits comparison o the viscosity ratios l of polymers having different V30 values, since the unnormali~ed V30/V300 ratio is a function of V30. The NVR is constant for any given catalyst over an MI2 range of about 30, and only slight deviations occur outside of that range.
In the examples, the following procedures are used to prepare -the catalyst compositions and polymers.
I PREPARATION OF CATALYSTS
¦¦ In the preparation of each of the catalysts, dry a I commercial inorganlc oxide by heating it under d~y, deoxygenated nitrogen for 5-16 hours at a tempera-ture of 200 ¦ -600 C. to provide an activated oxide containing about 1 -~1 1.4 mmols of available hyclroxyl yroups per gram. Cool the ¦l activatecl oxide to ambient l:emperature under a purifiecl nitrogen blanket, suspend it in commercial hexane, add neat ,l organometallic compound, and stir the resultant slurry for 30-60 minutes. Then add a vanadium compound in neat or solution form, stir the resultant slurry for an additional 30-60 minutes, add an alcohol~ stir for another 30-60 minutes, and remove the hexane under a nitrogen purge to !produce a powdered solid catalyst. The particular ¦lingredients used to prepare the catalysts, the amounts of llorganometallic, vanadium, and alcohol compounds added per ¦¦gram of inorganic oxide, and the particular temperatures used ¦to dry the inorganic oxides are shown in the examples and/or tables.
I ~ro~,g~
I -$~e~h ou~ the examples the commercial magnesium ;oxide used m Merck Maglite D, ~ inorganic oxide having a ¦Isurface area of about 150-200 square meters per gram, a pore Ijvolume of about 1.2-1.5 cc per gram, and an average particle ¦Is ze of about 30 - 40 microns; the cornmercial silica employed ~nrDavison 952 silica gel, an inorganic oxide having a ~surface area of about 250-350 square meters per qram, a pore volume of about 1.5-1.7 cc per gram, and an average particle ,~, /~ ~2~39~36 lll ! size of about 65-75 microns; the commercial alumina is Norton G376, an inorganic oxide llaving a surface area of more than ~i~
100 s~uare meters per gram and a pore ~d~of about 0.8-1.1 `I cc per gram; and the commercial aluminum silicate and i¦ magnesium silicate are ~. R. Grace's materials haviny the designations XSZ-AL-65C and XSZ-MG-66C, respectively.
!~ SLURRY POLYMERI ZATION
¦ Charge 1.5 liters of dry hexane to a suitable autoclave under a dry, deoxygenated nitrogen atmosphere, add i 2.1 mmols of triethyaluminum as ~ activator-scavenger, stir ,1 ~or 5 minutes, and add a slurry of 0.1-0.4 gram of catalyst I¦ powder in, respectively, 1-4 ml of commerical hexane. Raise the temperature of the reactor -to 85-90 C., add enough hydrogen to ensure the production of a polymer having a molecular weight such that its MI2 will be within the range ¦ of about 1-30, raise the reactor pressure to about 2.1 MPa I with ethylene, and any comonomer(s~ being employed, and hold ¦ the pressure at that level throughout the po~ymerization by ¦ adding monomer as needed. Immediately after pressurizing the reactor with monomer, add 0.17 mmol of chloroform as a l promoter; and, at 15-minute intervals thereafter, add ¦ supplemental 0.17 mmol aliquots of the promoter. After one hour, stop the polymerization by venting the autoclave, opening the reactor, and iltering the polymer from the liquid medium, and drying the polymer. Then dry the polymer under vacuum at 60 C for 4 hours.
LABORATO~Y GAS-PHASE POLYMERIZATION
The laboratory apyaratus consisted of a continuous ¦polymerization reaction system essentially as depicted by ¦ Miller in the drawing of ~.~S. Patent No. 4,003,712, with two ¦exceptions: there was no filter in the gas recycle line, and llthe catalyst was Eed to the reactor with nitrogen only. The ¦Ireaction zone was 10 cm in diameter, 120 cm tall. Recycle jllgas passed through a velocity reduction or disengaging zone ¦latop the reactor, through a cyclone separator, through a ! centrifugal compressor and into the bottom of the reactor -3~-1 ~26399~
I where the gas was distributed into the fluidi~ed bed by a l clispersion or distributiorl plate. fleat exchange was effeeted I Pressu r~z~d I by circula~ing~ ~Y~e~ tempered water through jacketing on the recycle gas piping. This system had a rated capacity of ~}50 g of polymer per hour. Generally, for catalyst screening studies, the system was opera-ted as follows:
¦l Introduce a stream or streams of ethylene,any ¦¦ comonomer(s), chloroform, and hydrogen to the reactor.
¦ Continuously withdraw unreacted or recycle gas from the top 'l of the disengaging zone, pass it through a heat exchanger to ¦~ maintain a bed temperature of about 95-100 C., and ¦l introduce it at the bottom of the reactor at a rate ¦I sufficient to give a superficial veloeity of about 25 em/sec in the bed.
troduc~ mak~-up monomer, ehloroorm, and hydrocJe into the recycle gas line so as to maintain eonstant gas composition as detected by on-line analyzers and so as to ¦I maintain the reaetor pressure at about 3.5 MPa and to provide ¦ about 40 mmols of ehloroform per mmoi of vanadium per hour, ¦l and feed fresh catalyst partieles into the reaetor below the ¦top of the bed so as to provide a vanadium feed rate of cne mmol per hour. Add triethylaluminum as a seavenger and coeatalyst during the polymerization so as to provide a triethylaluminum feed rate of 20 mmol per hour. Withdraw polymer produet semi-eontinuously from the bottom of the bed at a rate such as to maintain a constant bed level. Take ¦ aliquots of withdrawn polymer for testing.
I EXAMPLE I
¦I Prepare five eatalyst eompositions by the eatalyst ¦¦preparation proeedure described above, exeept for ~Ising no ¦aleohol in the preparation of the first eomposition. In eaeh 1l case, employ MgO as the inorganic oxid~, trie~hylalulninunl as 'Ithe organometallie eompouncl, ethoxyvanadium oxydichloride as ¦¦the vanadium eompound, and ethanol as the aleohol, when !lemployed; and dry the support at about 200 C. Use each of lil ;3~3~3~;
~ill ~ompoS ~t'n~
/ llthe cat~lyst CG.~ ti~n to prepare polyethylene by the / Islurry polymerization procedure described above. The amounts / If ingredients employed in the production of the catalyst / composltions, and the yields, melt indices, and normalized l viscosity ratios (NVR), i.e., molecular weight distributions, i of the polymers are shown in Table I
TABLE I
Run # Catalyst Composition Yield MI2 ~VR
I _ /Al(c2H5)3/Mgo70 g l.0 2.29 0.2 mmol l.0 mmol 1 9 1 C2~l5O~I/(C2~lsO)VOCl2/lO~ g ~.6 2.25 Al(C2ll5)3/M9O
0.2 mmol 0.2 mmol l.0 mmol l g ¦ 2 C2~l5OH/~C2H5O)VOC12/ 85 g 2.5 2.14 ll Al(C2H5)3/Mg il 0.5 mmol 0.2 mmol 1.0 mmol 1 g 3 C2H5O~/(c2Hso)vocl2/ 4.1 2.10 Al(c2H5)3/Mgo 1.0 mmol 0.2 mmol 1.4 mmol l g 4 C2ll5O~I/(Cz~5O)VOCl2/138 g ~.2 2.06 Al(C2H5)3/M~
I ¦ 1.4 mmol 0.1 mmol 1.4 mmol l 9 I _ _ ; I As demonstrated above, the addition of ethanol, as the last-added component, with an ethoxyvanadium oxydichloride/triethylaluminum/magnesium oxide catalyst composition results in the formation of a catalyst composition that narrows the molecular weight distribution of polymers ~ormed in its presence - this narroWlng of 'che molecular weight distribution being progressive as the amount I of ethanol used is increased from 0.2 to l.0 per mol of ~¦ triethylaluminum. The following example shows that polymers 63~j '11 having narrow molecul~r weight distributions c~n also be obtained when an alkylaluminum alkoxide is substituted for a 11 trialkyla1uminum in the practice of the invention EXAMPLE II t Prepare a catalyst composition by the catalyst It preparation procedure described above, usin~ MgO as the inorganic oxide, drying it at about 200 C., and sequentially reacting with 1.0 mmol of diethylaluminum ethoxide, 0.2 mmol of ethoxyvanadium oxydichloride, and 1.0 mmol of ethanol per gram of silica. When the catalys~ composition is used to prepare polyethylene by the slurry polymeriza-tion procedure described above, the process results in the production of 80 grams of polymer having a melt index of 3.0 and an NVR value of 2.12.
EXAMPI,E III
Prepare two C~30~ n-Clg~l37O)VOC12/ ( 2 5 3 2 catalyst eompP~s-}t-~e~ by the catalyst preparation procedure ~¦
described above, employing the same amounts oE ingredients in each case, i.e., 1.5 mmol of triethylaluminum, 0.2 mmol of n-octadecoxyvanadium oxydichloride, and 1.0 mmol of methanol per gram of silica, but using a drying temperature of about 200 C. for the sillca used in producing the first of the compositions and a drying temperature of about 550 C. for the silica used in producing the second of the compositions.
Then use each of the catalyst compositions to prepare polyethylene by the slurry polymerization procedure described above~ The yields, melt indices, and NVR values of the polymers are shown in Table II.
TABLE II
_.
¦ Run # Support Dry~ng Temp. Yield MI2 NVR
Il 200 C. 170 g 5.4 2.34
The reaction of the vanadium component with the treated support may also be accomplished by conventional means, such as any of the techniques described in British Patent ~o. 1,489,410.
However, it is st desirably accomplished simply by adding the vanadium compound in neat or solution form to the slurry of treated support and maintaining it in intimate contact with the treated support for a time sufficient to provide for substantial-ly complete reaction, usually at least about 5 mlnutes and preferably about 10-60 minutes, although, actually, the reaction is virtually instantaneous.
When reaction of the vanadium component with the treated support has been completed, reaction with the alcohol may be accomplished in any suitable manner, conveniently just by adding the alcohol to the vanadium component/treated support reaction product and maintaining it in contact therewith, e.g., by agitating the slurry, for a time sufficient to ensure sub-stantial completion of the desired reaction, usually at least about 5 minutes and most commonly about 30-60 minutes. All that is critical about the manner in which the alcohol is reacted with the other catalyst components is the time at which it is added to the system. Reaction of the other components with one another must be substantially complete before the alcohol is ~: 30 added in order Eor the catalyst compositions to have the desired performance capabilities.
~' ,. .~,~
39~ 1 /~ I
fter the alcohol has b~en reacted with the othcr c~talyst compone~ts, the resultant catalyst composition may or may not require further treatment to make it suitable for use, depending on the particular process that has been used to prepare the catalyst composition and the particular type of polymerization process in which it is to be used. For example, if the catalyst composition has been prepared by a type of process which results in its being already dry when reaction with the alcohol has been accomplished, no further treatment is likely to be necessary if the composition is to be used in a gas-phase polymerization process; but slurrying of the composition in a suitable liquid medium may be desirable if it is to be used in a slurry or solution polymerization process. On the other hand, if the catalyst composition has been prepared by the preferred process described ~bove, i.e., if the inorgar-ic oxide has been slurried in a liquid medium prior to the addition of the other components, it is already suitable for use in a slurry or solution polymerization process but will have to be dried to make it suitable for use in a gas-phase polymerization process. When the composition is to be dried, i.e., freed of any liquid medium used in its preparation, the drying may be achieved by any conventional technique, e.g., filtration, certrifugation, evaporation, blo~ing with nitrogen, etc.
Commerical preparation of the catalyst of this invention is preferably carried out as taught by Rogers in U.S. Patent No.
4,426,317.
Regardless of the particular techni~ue used to prepare the catalyst compositions of the invention, it should be kept in mind that~they are Ziegler catalysts and are therefore susceptible to poisoning by the materials, such as oxygen, water, etc., that are known -to reduce or des-troy the effectiveness of Ziegler catalysts. A~cordingly, they should be prepared, stored, and used under conditions that will !
,, ij ~o ~,3~3~36 permit them to be useful as polymerization catalysts, e.g., by the use of an inert gas atmosphere, such as nitrogen.
~ he invention is particularly advantageous in that it provides catalyst compositions which (1) have the active in-gredients chemically-attached to an inorganic oxide support, (2) are capable of producing ethylene polymers having a narrow-to-intermediate molecular weight distribution, as desired, and a good balance of physical properties by an economical gas-phase process that gives a high yield of polymer and ~3) do not foul 1~ gas-phase reactors. The fact that high yields of polymer can be obtained by the use of the catalyst compositions is particu:Larly unexpected in that these high yields are attalnable even when the catalyst compositions a.re prepared b~ th~ preferrecl p.rocess whe.rein no washing step is required or utilized during or after preparation of the compositions. Both experience in the field and the teachings of the prior art indicate that at least one washing step should be required in the preparation of such com-positions when high yield catalysts are desired.
After the catalyst composition of this invention is prepared, it is subseqNently introduced into a gas-phase fluid-ized reactor similar to that taught by Miller in United States Patent No. 4,003,712. In a preferred embodiment of the invention, the diameter of the velocity reduction or disengaging zone at the top of Miller's reactor is enlarged and the cyclone and filter in the gas recycle system are eliminated for stable, long-term commercial operation. It should be understood that polymeriza-tion with the catalyst compositions o this invention may be conducted in any fluidized system which has a distribu~ion plate means and allows a monomer gas to fluidize a bed including the catalyst compositions; allows unreacted monomer gas to be re-recycled fr.om the top of the fluidized system back to the bottom of the fluidized system :! 21 3~3~
/ li or for admixing with thc monomcr gas prior to its diffusing / or passing thro~yh the fluid.ized bed; allows a polymer / !I product to be withdrawn from the fluidized bed; allows i catalyst and a trial~ylaluminum to be added to the fluidized bed; and provides for the removal of the heat of polymerization. Size, shape, pressure rating, heat removal i¦ capability, and other factors can limit the polymer production capacity of the gas-phase fluidized-bed reaction Il systems of this invention. The process of this invention may ¦I be practiced in commercial facilities having production ¦ capacities of 50,0~0 to 250,000 metric tons per year or more.
The process of this invention may also be practiced in laboratory scale reactors having a production capacity of from about 0.1 to 1.0 kg/hr or in pilot p:Lant reactors having ¦ p.rocluctlon capac.i~i~s oE Erom S to 5Q0 Ic~/hr.
¦ ~'h~ c~talyst compositions oE ttliS lnvelltLon should preferably be injected or Eed to the fluidized bed system at a point between the distribution plate and about 7/8 o~ the height of the catalyst bed from the distribution plate of the ! reactor. More preferably, the catalyst compositions are fed il into the fluidized bed system at a point of between about 1/8 ¦ to about 1/2 of. the heigh-t of the fluidized bed. Injection ! of the catalyst composition above about 1/8 of the height of the bed (as opposed to below 1/8 of the height) offers distribution of the catalyst composition throughout the ¦ entire ongoing fluidized bed to retard and/or preclude the 1~ formation of localized spots of high catalyst composition ¦¦ concentration which would result in the formation of "hot ¦¦ spots" at or near thc distri.bution plate~ A "hot spot" is a ¦¦ localized region ln which the~exothermic heat of .
polymerization is not dissipated before some polymer h~ to ¦¦ the softening point of the polymer. Any introduction of -the ~ 4~1yS~
`! ~ t~ t~ compositions o-f this invention at a point above i about 7/8 of the height of the fluidized bed frotn the distribution plate of -the reactor rnay lead to excessive ¦ carryover of the fresh catalyst of this invention into the ~ ,2-39~36 gas recycle system. The rate of injection or rate of feed of the catalyst composition of this invention is any suitable rate which is equal to catalyst consumption in the polymerization process of this invention and generally depends on the size of the fluidized bed system. The rate of production of the particulate polymerized substantially ethylene particles in the fluidized bed is partly determined by the rate of catalyst injection. We have found that the rate of injection of the catalyst for our polymerization i~
process is generally preferably at a rate that maintains the concentration of the vanadium in the fluidized bed between about 1/10 ppm to about 50 ppm based on weight of vanadium metal divided by total solids in the bed. More preferably, the rate of injec:tion oE the catalyst is that which would maintaln the concentrakion Oe the vanadium .in thc ~luldlæed bed between about 0.50 ppm to about 10 ppm; most preferably, between about 1 ppm to about 4 ppm. The fluidized bed is substantially particulate polymerized ethylene polymer particles formed by polymerization of the monomer~s) on the catalyst compositions of this invention.
In order for the catalyst composition of this invention to give high yield of polymer product per unit of vanadium component, we have discovered that it is necessary to add or inject at least one trialkylaluminum compound into the fluidized bed system as a co-catalysts. For a variety of reasons, it is preferred to add the trialkylaluminum compound, or the mixture of trialkylaluminum compounds, that i5 being used as a co-catalyst directly to the fluidized bed il separately and independently of the catalyst and at an injection point removed from the catalyst injection point.
However, the process of this invention does not depend on the method of feeding the trialkylaluminum co-catalyst or the location of its injection point. The trialkylaluminum compounds of this invention may be fed to the f luidized bed as pur~ compounds, or in solution in a liquid hydrocarbon which will vaporize in the fluidized bed. Suitable ~ ~i399~:i ~
hydrocarbon solvents include, but are not limited to, isobutane, isopentane, hexane, heptane and mixtures ~hereof.
The trialkylaluminum oE ~his in~ention snay be any trialkylaluminum wherein the alkyl or combination of alkyl groups contain between 1 and about 36 carbon atoms. In a preferred embodiment of the invention, the alkyl group or combination of alkyl groups contain between 1 and about 12 carbon atoms. Suitable trialkylaluminum compounds have been found to lnclude trimethyl-, triethyl,- tri-i-butyl-, tri-n-hexyl-, tri-n-octyl- and ethyl di-i-butylaluminum. It should be understood that trialkylaluminum compounds add ethylene, and alpha olefins to some extent, under the operating temperatures ~lld pressures o~ the polymerization process of ttle invention. rrhus, an ethyl group on alum.irluln may he inserted by ethylelle to become~ a butyl group, etc.
Therefore, there is no reason to believe or require that all alkyl groups on the aluminum be -the same. There is every reason to believe that mixtures of trialkylaluminum compounds are generated during polymerization and are as effective as pure compounds. Since the exact composition of the alkyl groups on aluminum during the polymerization process of this invention is not known because of the ethylene insertion reaction, all of the -trialkylaluminum species in the fluidized bed are referred to collectively Eor the purposes herein as "trialkylaluminum".
As was the case for the catalyst composition of this invention, the rate of injection of the trialkylaluminum is also any suitable rate which is equal to the trialkylaluminum consumption in the polymerization process, and also depends on the size of the fluidized bed system. Polymer productivity from the polymerization process is not only determined by the rate of catalyst injection, but also from the rate of trialkylaluminum injection.
~ ;39~36 Assuming that the trialkylaluminum compounds of this inventionremain in the fluidized bed and assuming uniform distribution of trialkylaluminum throughout the fluidized bed, the molar concentration of trialkylaluminum may be calculated from the molar feed rate of the trialkylaluminum being fed into the fluidized bed reaction system and the withdrawal rate of the polymer product particles. Likewise, assuming uniform distribution of the catalyst composition throughout the fluidized bed, the molar concentration of the vanadium component of the catalyst composition may be calculated from the molar feed rate of the vanadium component of the catalyst composition being fed into the fluidi~ed bed reaction system and the withdrawal rate of the polymer product particles. At stable, lined-out operating conditions, the ratio of the molar concentratlon of the trialkylaluminum to the molar concentration o~ the vanadium compon~nt in the hed of catalyst composition will asymptote to the ratio of the molar feed rate of the trialkylaluminum to the molar feed rate of the vanadium components oE the catalyst composition of this invention.
For -the catalyst composition of this invention, the injection rate of the trialkylaluminum should be such that the Al/V
ratio in the ~luidized bed of the molar concentration of the trialkylaluminum to the molar concentration of the vanadium component is between about 1 to about 5,000. We have ~ound that the activity of the catalyst composition of the invention is maximized in a certain range of trialkylaluminum to vanadium molar ratio. Too little or too much trialkylaluminum suppresses the activity of the catalyst composition and the polymer production. It has been determined that a plot of the trialkylaluminum to vanadium molar ratio versus the catalyst (of this invention) activity possesses a generally flat peak and the optimum trialkylaluminum to vanadium molar ratio lies in the range of from about 2 to about 500, with from about 2 to 60 being the most preEerred from the standpoint of m~nimizinq c-talyst / ~ 3~36 / residue levels in the polymer and trialkylaluminum cost.
/ Therefore, the preferred injection rate of the / trialkylaluminum into the fluidized bed system of this / invention is that injection rate whercin the molar ratio in / ¦ the fluidized bed of the molar concentration of the ~I trialkylaluminum to the molar concentration of the vanadium il composition is between about 2 to 500, and most preferably ¦¦ from about 2 to about 60.
¦ The bed of particulate polymerized substantlally I¦ ethylene particles, trialkylaluminum ancl the catalyst ! composition oE this invention has to be fluidized at a l pressure of between about 0.7 and 4.2 MPa and a temperature i of between about 50 to 120 C. Fluidization is conducted by ¦ diffusing underneath the bed (and through the distribution plate) a gas mixture comprising ethylene, hydrogen and chloroform at a reltc sufEicicnt enougll to cJive c~ lineclr gas velocity in the bed oE between about 15 to about 60 cm/sec.
¦ The gas mixture will also include inert gas which is used to ¦ feed the catalyst~ compositions to the fluidized bed. A
majority of the gas mixture is in the form of unreacted gas mixture that is recycled from the top of the reaction zone to l the bottom of the fluidized bed of the reaction zone.
¦¦ Although the catalyst compositions and the ¦I tr:ialkylaluminum of this invention polymerize ethylene and ! other olefins over a wide range of temperatures, there is a ~1 practical limitation to the temperatures at which -the gas-phase fluidized-bed process of this invention is I commercially viable. For example, above about 120 C, ¦ ethylene polymers soften and tend to agglomerate in a ¦ fluidized bed, leading to formation of lumps, loss oE
jj fluidization, and onset of an inoperable condltion. ~elow about 50 C, the production rate of commercial reactors becomes so low that the process is no longer profitable. It , is generally desirable to operate near the highest ! temperature at which the polymer will not agglomerate in thc ~I bed with a temperature safety factor for small temperature A~ 26-~ r~ 3 ~316 u~sets so th~t inoperable conditions are not encountered even brief1y. Tlle~refore, the preferred temperature range is from about ~ C, with the range from about ~ C being most preferred.
The pressure at which the polymerization process of this invention is conducted is selected on the basis of desired commercial operation rather than upon some limitation of the catalyst. The catalysts of this invention will function at atmospheric, subatmospheric, or superatmospheric pressures. For economy of operation, one wishes to polymerize near the highest pressure for which the equipment is designed in order to maximize the production rate for the equipment. But, because commercia1 process equipment generally is rnore expcns.iv~ with the higher pre~ssure, there is a natura1 tencl~llcy to d~sign commercial equipm~ Eor low pressures. Thes~ constraints lead to a commercial operating range of about 0.7 - 4.2 MPa. At the lower pressures, however, higher dwell or residence times in the reactor are required to reach high yields of polymer per unit of ¦catalyst. At the higher pressures, there is little room to safely accommodate pressure upsets. These constraints lead to a preferred pressure range of about 1.6 - 3.9 MPa.
In order to provide sufficient mixing and agitation in the bed of trialkylaluminum and catalyst that "hot spots"
will not develop, it is necessary that the flow rate of -the gas mixture through the bed of polymer particles containing traces of the catalyst and the trialkylaluminum be sufficient to fluidize the particles. For the powdered polymer C~fa ~Ysf' particles produced by the cataly~ compositions of this invention, the minimuln fluidization velocity, Gmf, has been determined to be about 15 cm/sec. As gas velocity increases, a point is reached at which thè particles are largely swept out of the bed by the force of the rising gas ~the transport velocity), which, for the particles of the prese~t invention jjis about 4 Gmf, or 60 cm/sec. To provide some margin for ',1 !1 -27- l ,~.~,i i . Il .
j;3~6 1~
¦!
o~er~tirlg exror, ttle preferred velocity range is about 1.5 -3.0 G~lf, or about 23 - 45 cm/sec, in contrast to the 3 - 5 G~nf range pre~erred by Miller in U.S. Patent No. 4,003,712 ~;
for his catalysts.
The cat~lysts of this invention, under the commercial conditions descri~ed above, in the absenc2 of a chain transfer agent, produce polymer of a molecular weight too high for conventional melt processing. Therefore, in the i commercial practice of this invention the fluidi~ing gas :~¦
mixture must CQntain hydrogen during polymerization to adjust the molecu ar weight ~as determined ùy melt index~ to the ¦
desired range for the product being produced. This is done by increasing the hydrogell/ethylene ratio to raise melt index ;
~lower molecular weight), or reducing the ratio to produce the opposite eEect. The catalyst compositions o~ this invention are sensltive to hydrogell, so lt is yenerally not necessary to use more than 10~ by vol. of hydrogen even -to produce the highest melt index polymer. Furthermore, when used as described herein, altering the hydrogen/ethylene ratio to increase melt index does not cause a loss of production rate in a commercial plant within the range of melt indexes used for commercial polymers at this time.
Preferably, the amount of hydrogen utilized ln a preerred embodiment o~ the invention in order to control the molecular w2ight o the produced polymer is between about 0.10 ~ to about 10.0 % by volume of the total gas mixture volume.
The gas mixture has to have chloroform in order that the catalyst compositions of this invention can have their activity promoted. While o-ther halogenated carbon f,~ o7~r~lch~oro~e~) a~æ
compounds such as methylene chloride and ~3tr~ G~ Om~hamr may work as promoters, from the standpoints of promotion of catalyst activity, cost, availability, ease of handling, and catalyst promotion without causin~ reactor fouling, chloroEorm is clearly the compound oE choice. Only small amounts are needed because of its effectiveness. Uncler the conditions of polymerization, it is a gas, and generally will ~3~ i / ~ be present in the recycle gas at concentrations between about 0.0001 to about 1.000 % by vol of the gas mixture. Since the ¦¦ prefcrred vol ~ ranges for hydrogen and chloroform is ¦¦ r~spectively between about 0.10 and about 10.0 and between il about 0.0001 and about 1.000, the remaining vol % for any given volume of the gas mixture would include ethylene and !¦
,¦ any of the inert gas which is used to feed the catalyst 1i compositions to the fluidized bed in the reaction zone. In a preferred embodiment of the invention, ethylene preferably comprises between about 50.0 vol % and about 99.9 vol % of the gas mixture.
t appears that the molar ratio CHC13/V is more l useful in predicting and understanding its effect than the I overall concentra~ion in the gas, since it afEects the catalyst's per~ormance. The CIIC13/V ratio may vary Erom ! about 2 to about 5000. ~ecause chloroform :is relativcLy nexpensive and used in small amounts, there is no real ¦¦economic incentive to minimize its use. However, there lappears to be a maximum in the curve of catalyst activity vs.
¦ CHC13/V rati~, with a broad optimum in the range of about 10 - 500. There also appears to be an interac-tion between the optima for CHC13/V ratio and A1/V ratio such that lower ¦C~C13/V ratios are generally preferred when the A1/V ratio is Illow, and higher CHC13/V ratios are generally preferred when ¦I the Al/V is high. Other factors, such as impurity levels, ¦jmay also cause a shift in the optimum CHC13/V ratio or A1/V
ratio, but generally such factors will not shift-the optima outside the preferred ranges.
1l We have found that, in order to control the density I ¦of the produced ethylene polymer, the gas mixture of ethylene, hydrogen and chloroform may include alpha olefins ¦which will be copolymerized with the ethylene of the gas limixture. Although the catalyst compositions of this ¦jinvention will copolymerize essentially any alpha olefin with ¦lj ethylene, there is a practical limit to what can be li i39~36 /~1 effectively done in a gas-phase reaction. Generally, olefins havlrlg more than 8 carbon atorns have too low a vapor pressure to be used in high enough concentration to have much effect on density. Propylene, butene-l, hexene-l, 4-methylpentene-1, and octene-l are among the alpha olefins useful in copolymerization with ethylene in this invention.
Preferably, mixtures of alpha olefins having 3 to 8 carbon atoms are used in a preferred embodiment of this invention.
By this process, polymers generally considered to be HDPE
(densities of 0.940 or greater) and LLDPE (densities below 0.940) may be made equally well by adjusting comonomer concentration in the feed or other factors. The amount of ¦~
comonomer needed is determined by the density of the polymer product being made. Generally, no~ less than 0~5 vol ~ of alpha olefin will be used ~ncl not morc than 30 vol ~ Oe th~
alpha olefin will be utllized for any given volu~ne of the gas mixture along with any of the inert gas and between about 0.10 vol % and about 10.Q vol % of hydrogen, between about 0.0001 vol % and about 1.000 vol % chloroform, and between about 50.0 vol ~ and about 99.4 vol ~ ethylene.
The catalyst compositions of this invention are preferably fed to the gas-phase fluidized-bed reactor as~*r~-particulate matter, such as dry powder under the inert gas.
Any gas that does not react with the catalyst is considered inert. Suitable inert gases include nitrogen, argon, and methane. Any dev1ce which can measure and convey a free-flowing powder is suitable for feeding the catalyst, although the device must not allow monomer to enter the catalyst storage are~ of the feed device. Once the catalyst has b~en measured and delivered to the catalyst feed line, any good method of conveying it to the fluidized bed may be used.
These include mechanical means such as screw conveyers, or gas conveying with inert gas or, as Miller teaches, with recycle gas from the reactor. Catalyst may be added continuously, semi-continuously, or discontinuously to the r~actor. Continuous addition is preferred, but ls virtually 1,1 1.~ 3~6 I ilnpossible at laboratory scale. Catalyst may be fed pure or Il may b~ dil~lted with any free-fl~wing particulate material such as pure, dry support or polymer powder from the reactor.
¦ In catalyst feeding, all that is ~eally critical is that the catalyst be fed at a controlled rate and be dispersed in the bed before a "hot spo-t" develops.
¦ The produced particulate polymerized su~stan~ially ethylene particles may be removed from the gas-phase reaction zone by any suitable means and at any suitable location.
Preferably, the produced ethylene polymer particles are removed in accordance with the procedure described by Miller in U. S. Patent No. 4,003,712. In a preferred embodiment of the invention, the producecl ethylene polymer particles are removcd from the gas-phase reaction zone above and in uroximity to tho distrib~ltion pla~e.
~s has been mentioned, it is necessary to ttave good ¦ fluidization, good catalyst ~ixing, and good distribution of ~¦ gas in the bed in order to avoid l'hot spots" which cause ¦ lumps to form in the bed. These lumps themselves disturb ¦¦ fluidization so, once a lump forms, the tendancy for other ¦¦ lumps to form is enhanced. Eventually a reactor shut down is ¦necessary because the process becomes inoperable.
Similarly, i-t is necessary for long-term, stable ¦operation of commercial reactors that the surfaces of the ¦reactor and distribution plate remain clean. If a polymer coating (fouling) builds up on a reactor surface, several ¦undesirable things may happen. First, fouling on the ¦Idistribution plate tends t~ perturb the desired gas ~,distribution and restrict the abilitytxJ~the poly~er ¦¦par-ticles at the plate to ~ove laterally. Both effects tend !Ito produce "hot spots" at or near the distribution plate.
¦!Second, fouling on the reactor wall inhibits the normal ¦¦downward motion oE fluidized part-cles at the wall surface.
¦IParticles which "hallg up" at a wall surface can ~Jenexate "hot 'spots". Third, the wall coating may come loose in places, I
.
il -31-- ~,rl,' /~ ~L2~39~6 fall into the bed, and disrupt fluidization as any lump would do. Even worse, wall fouling usually is in the form of a "slleet" rather than a lump, and produces severe gas channelling in the bed if it falls off.
Although poor selection of operating conditions or poor operating techniques may lead -to lump formation, it appears that fouling of reactor surfaces depends primarily on j the catalyst used. Some catalysts tend to produce J
rouling,and some do not. At this time, insufficient experience has been gained to be able to predict wi-th r~
accuracy which catalyst compositions will foul and which will give stable operation for months without fouling reactor surfaces. Obviously, for economical commercial operation, the catalyst must not Eoul reactor surfaces. Fouling in a commercial r~clctcr l~a~ls ~o "down time" with consequen~ Loss oE production and ~xtr;l m~int~llance cost for cleaning. Thus, fouling will cause a gas-phase fluidized-bed process to lose its economic advantage over slurry processes.
The following examples are given to illustrate the invention and are not intended as a limitation thereof. In these examples, compositions and processes that are illustrative of the invention are distinguished from those that are outside the scope of the invention and are included only for comparative purposes by using an alphabetic designation for any example or run that is a comparative example and a numeric designation for the examples and runs that are illustrative of the invention. Yields given in the examples are measures of productivity in terms of the number of grams of polymer produced per gram of catalyst per hour, melt indices (MI2)~are those determined by ASTM test D-1238-65T using a 2160-gram weight, while the NVR values are "normalized" melt viscosity ratios determined by measuring the apparent viscosi-ties of the polymers at 30 sec 1 and 300 sec. 1, respectively, at 200 C. in an Instron caplllary rheometer and (2) normalizing them to V30=5 by the equation.
NVR=antilog (0.14699~0.7897 log V30 - log V300) I
i -3~
3~3~3~j l I where v30 and V300 are the measured apparent viscosities.
I This normalization permits comparison o the viscosity ratios l of polymers having different V30 values, since the unnormali~ed V30/V300 ratio is a function of V30. The NVR is constant for any given catalyst over an MI2 range of about 30, and only slight deviations occur outside of that range.
In the examples, the following procedures are used to prepare -the catalyst compositions and polymers.
I PREPARATION OF CATALYSTS
¦¦ In the preparation of each of the catalysts, dry a I commercial inorganlc oxide by heating it under d~y, deoxygenated nitrogen for 5-16 hours at a tempera-ture of 200 ¦ -600 C. to provide an activated oxide containing about 1 -~1 1.4 mmols of available hyclroxyl yroups per gram. Cool the ¦l activatecl oxide to ambient l:emperature under a purifiecl nitrogen blanket, suspend it in commercial hexane, add neat ,l organometallic compound, and stir the resultant slurry for 30-60 minutes. Then add a vanadium compound in neat or solution form, stir the resultant slurry for an additional 30-60 minutes, add an alcohol~ stir for another 30-60 minutes, and remove the hexane under a nitrogen purge to !produce a powdered solid catalyst. The particular ¦lingredients used to prepare the catalysts, the amounts of llorganometallic, vanadium, and alcohol compounds added per ¦¦gram of inorganic oxide, and the particular temperatures used ¦to dry the inorganic oxides are shown in the examples and/or tables.
I ~ro~,g~
I -$~e~h ou~ the examples the commercial magnesium ;oxide used m Merck Maglite D, ~ inorganic oxide having a ¦Isurface area of about 150-200 square meters per gram, a pore Ijvolume of about 1.2-1.5 cc per gram, and an average particle ¦Is ze of about 30 - 40 microns; the cornmercial silica employed ~nrDavison 952 silica gel, an inorganic oxide having a ~surface area of about 250-350 square meters per qram, a pore volume of about 1.5-1.7 cc per gram, and an average particle ,~, /~ ~2~39~36 lll ! size of about 65-75 microns; the commercial alumina is Norton G376, an inorganic oxide llaving a surface area of more than ~i~
100 s~uare meters per gram and a pore ~d~of about 0.8-1.1 `I cc per gram; and the commercial aluminum silicate and i¦ magnesium silicate are ~. R. Grace's materials haviny the designations XSZ-AL-65C and XSZ-MG-66C, respectively.
!~ SLURRY POLYMERI ZATION
¦ Charge 1.5 liters of dry hexane to a suitable autoclave under a dry, deoxygenated nitrogen atmosphere, add i 2.1 mmols of triethyaluminum as ~ activator-scavenger, stir ,1 ~or 5 minutes, and add a slurry of 0.1-0.4 gram of catalyst I¦ powder in, respectively, 1-4 ml of commerical hexane. Raise the temperature of the reactor -to 85-90 C., add enough hydrogen to ensure the production of a polymer having a molecular weight such that its MI2 will be within the range ¦ of about 1-30, raise the reactor pressure to about 2.1 MPa I with ethylene, and any comonomer(s~ being employed, and hold ¦ the pressure at that level throughout the po~ymerization by ¦ adding monomer as needed. Immediately after pressurizing the reactor with monomer, add 0.17 mmol of chloroform as a l promoter; and, at 15-minute intervals thereafter, add ¦ supplemental 0.17 mmol aliquots of the promoter. After one hour, stop the polymerization by venting the autoclave, opening the reactor, and iltering the polymer from the liquid medium, and drying the polymer. Then dry the polymer under vacuum at 60 C for 4 hours.
LABORATO~Y GAS-PHASE POLYMERIZATION
The laboratory apyaratus consisted of a continuous ¦polymerization reaction system essentially as depicted by ¦ Miller in the drawing of ~.~S. Patent No. 4,003,712, with two ¦exceptions: there was no filter in the gas recycle line, and llthe catalyst was Eed to the reactor with nitrogen only. The ¦Ireaction zone was 10 cm in diameter, 120 cm tall. Recycle jllgas passed through a velocity reduction or disengaging zone ¦latop the reactor, through a cyclone separator, through a ! centrifugal compressor and into the bottom of the reactor -3~-1 ~26399~
I where the gas was distributed into the fluidi~ed bed by a l clispersion or distributiorl plate. fleat exchange was effeeted I Pressu r~z~d I by circula~ing~ ~Y~e~ tempered water through jacketing on the recycle gas piping. This system had a rated capacity of ~}50 g of polymer per hour. Generally, for catalyst screening studies, the system was opera-ted as follows:
¦l Introduce a stream or streams of ethylene,any ¦¦ comonomer(s), chloroform, and hydrogen to the reactor.
¦ Continuously withdraw unreacted or recycle gas from the top 'l of the disengaging zone, pass it through a heat exchanger to ¦~ maintain a bed temperature of about 95-100 C., and ¦l introduce it at the bottom of the reactor at a rate ¦I sufficient to give a superficial veloeity of about 25 em/sec in the bed.
troduc~ mak~-up monomer, ehloroorm, and hydrocJe into the recycle gas line so as to maintain eonstant gas composition as detected by on-line analyzers and so as to ¦I maintain the reaetor pressure at about 3.5 MPa and to provide ¦ about 40 mmols of ehloroform per mmoi of vanadium per hour, ¦l and feed fresh catalyst partieles into the reaetor below the ¦top of the bed so as to provide a vanadium feed rate of cne mmol per hour. Add triethylaluminum as a seavenger and coeatalyst during the polymerization so as to provide a triethylaluminum feed rate of 20 mmol per hour. Withdraw polymer produet semi-eontinuously from the bottom of the bed at a rate such as to maintain a constant bed level. Take ¦ aliquots of withdrawn polymer for testing.
I EXAMPLE I
¦I Prepare five eatalyst eompositions by the eatalyst ¦¦preparation proeedure described above, exeept for ~Ising no ¦aleohol in the preparation of the first eomposition. In eaeh 1l case, employ MgO as the inorganic oxid~, trie~hylalulninunl as 'Ithe organometallie eompouncl, ethoxyvanadium oxydichloride as ¦¦the vanadium eompound, and ethanol as the aleohol, when !lemployed; and dry the support at about 200 C. Use each of lil ;3~3~3~;
~ill ~ompoS ~t'n~
/ llthe cat~lyst CG.~ ti~n to prepare polyethylene by the / Islurry polymerization procedure described above. The amounts / If ingredients employed in the production of the catalyst / composltions, and the yields, melt indices, and normalized l viscosity ratios (NVR), i.e., molecular weight distributions, i of the polymers are shown in Table I
TABLE I
Run # Catalyst Composition Yield MI2 ~VR
I _ /Al(c2H5)3/Mgo70 g l.0 2.29 0.2 mmol l.0 mmol 1 9 1 C2~l5O~I/(C2~lsO)VOCl2/lO~ g ~.6 2.25 Al(C2ll5)3/M9O
0.2 mmol 0.2 mmol l.0 mmol l g ¦ 2 C2~l5OH/~C2H5O)VOC12/ 85 g 2.5 2.14 ll Al(C2H5)3/Mg il 0.5 mmol 0.2 mmol 1.0 mmol 1 g 3 C2H5O~/(c2Hso)vocl2/ 4.1 2.10 Al(c2H5)3/Mgo 1.0 mmol 0.2 mmol 1.4 mmol l g 4 C2ll5O~I/(Cz~5O)VOCl2/138 g ~.2 2.06 Al(C2H5)3/M~
I ¦ 1.4 mmol 0.1 mmol 1.4 mmol l 9 I _ _ ; I As demonstrated above, the addition of ethanol, as the last-added component, with an ethoxyvanadium oxydichloride/triethylaluminum/magnesium oxide catalyst composition results in the formation of a catalyst composition that narrows the molecular weight distribution of polymers ~ormed in its presence - this narroWlng of 'che molecular weight distribution being progressive as the amount I of ethanol used is increased from 0.2 to l.0 per mol of ~¦ triethylaluminum. The following example shows that polymers 63~j '11 having narrow molecul~r weight distributions c~n also be obtained when an alkylaluminum alkoxide is substituted for a 11 trialkyla1uminum in the practice of the invention EXAMPLE II t Prepare a catalyst composition by the catalyst It preparation procedure described above, usin~ MgO as the inorganic oxide, drying it at about 200 C., and sequentially reacting with 1.0 mmol of diethylaluminum ethoxide, 0.2 mmol of ethoxyvanadium oxydichloride, and 1.0 mmol of ethanol per gram of silica. When the catalys~ composition is used to prepare polyethylene by the slurry polymeriza-tion procedure described above, the process results in the production of 80 grams of polymer having a melt index of 3.0 and an NVR value of 2.12.
EXAMPI,E III
Prepare two C~30~ n-Clg~l37O)VOC12/ ( 2 5 3 2 catalyst eompP~s-}t-~e~ by the catalyst preparation procedure ~¦
described above, employing the same amounts oE ingredients in each case, i.e., 1.5 mmol of triethylaluminum, 0.2 mmol of n-octadecoxyvanadium oxydichloride, and 1.0 mmol of methanol per gram of silica, but using a drying temperature of about 200 C. for the sillca used in producing the first of the compositions and a drying temperature of about 550 C. for the silica used in producing the second of the compositions.
Then use each of the catalyst compositions to prepare polyethylene by the slurry polymerization procedure described above~ The yields, melt indices, and NVR values of the polymers are shown in Table II.
TABLE II
_.
¦ Run # Support Dry~ng Temp. Yield MI2 NVR
Il 200 C. 170 g 5.4 2.34
6 550 C. 198 g 4.6 1.99 37~
399 Ei 11 I The preceding example and the following three l examples show that the use of different inorganic oxides, ¦ different alkoxyvanadium compounds, and different alcohols I which may or may not have the same chain length as the alkoxy l groups of the vanadlum compounds employed, as well as the use of diEferent support drying temperatures, are permissable within the scope of the invention and lead to the formation .
! of catalyst compositions that can be used to prepare polymers ! having narrow-to-intermediate molecular weight distributions.
l These examples also show that, in general, narrower molecular ¦¦ weight distributions are obtained when the catalysts used in the preparation of ethylene polymers are formed by the use of supports that have been dried at the higher temperatures within the preEerred range of drying temperatures taught in , the speciflcation.
EXAMPL~ tV
I Prepare three n-C8~l17~l/(n C8~17 ) 2 Al(C2H5)3/SiO2 catalyst compositions by the catalyst ¦preparation procedure described above, employing the same amounts of ingredients in each case, i.e., 1.4 mmol oE
triethylaluminum, 0.2 mmol of n-octoxyvanadium oxydichloride, and 1.0 mmol of n-octanol per gram of silica, but using . different dryiny temperatures for the silica used in ¦producing each of the compositions, i.e., 200 C., 350 C., ¦and 550 C., respec-tively.` Then use each of the catalyst ,I!compositions to prepare polyethylene by the slurry ,¦polymerization procedure described above. The yields, melt indices, and NVR values of the polymers are shown in Table IIIII.
TABLE III
I,Run # Support Drying Temp. Yield MI2 NVR
il7 200 C. 55 g 1.8 2.32 8 350 C. l46 g 2.1 2.~1 ilg s5oo C. 320 g 20.2 l.9S
~ 38-39'36 I EXAMPLE V
I Prepare two n-c~ 7oH/(n-c~Hl7o)vocl2/Al(c2~l5)3/
~¦ A12O3 catalyst compositions by the catalyst preparation ¦ procedure described above, employing the same amounts of ¦ ingredients in each case, i.e., 1.4 mmol of triethylaluminum, 1 0.2 mmol of n-octoxyvanadium oxydichloride, and 1.~ mmol of ¦ n-octanol per gram of alumina, but using~a drying temperature of about 200 C. for the alumina used in producing the first of the compositions and a drying temperature of about 550 C.
for the alumina used in producing the second of the compositions. Then use each of the catalyst compositions to Il prepare polyethylene by the slurry polymerization procedure ¦I described above. The yields, melt indices, and NVR values of ~ the polymers are shown in Table IV.
I T~\BLE IV
l _ _ ~¦ Run # Support Drying Temp. Yield ~I2 NVR
200 C. 47 9 6.9 2.16 11 550 C. 83 g 11.6 1.65 ¦ EXAMPLE VI
~ pare two nac8~ll7oH/(n-c8Hl7o)~ocl2/A ( 6 13 3 A12O3 catalyst compositions by the catalyst preparation jl procedure described above, employing the same amounts of ¦ ingredients in each case, i.e., 1.5 mmol of tri-n-hexylaluminum, 0.2 mmol of n-octoxyvanadium oxydichloride, and 1.0 mmol of n-octanol per gram of alumina, but using a drying temperature of about 200 C. for the alumina used in producing the first of the compositions and a drying temperature of about 500 C. for the alumina used in i producing the second of the compositions. Then use each of the catalyst compositions to prepare polyethylene by the slurry polymerization procedure described above. The yields melt indices, and NVR values of the polymers are shown in Table V.
!~
~1 ~39~
;3~:396 ~I ill ¦l TABLE V
11 ;I,i / IlRun ~ Support Drying Ternp. Yield MI2 NVR
~ _ - ~h 12 200C. 48 g - 1.91 , , 13 500 C. 355 9 18.6 1.67 As demonstrated above, particularly when ~12 of this example is compared with Run ~10 of the preceding example, the substitution of a higher trialkylaluminum for a lower trialkylaluminum in preparins -the catalyst compositions of the invention can lead to a narrowing of the molecular weight distribution of polymers formed in the presence oE the catalyst compositions when all ~ther factors are substantially constant.
EXAMPL~ VII
Prepare three n-c8~1L7o~l/(n-c8Ell7o)vocl2/
"p o~ 'vn ~
Al~C6lll3)3/inorganic oxide catalyst-eem~e~tio~ by the catalyst preparation procedure described above, employing the same amounts of ingredients in each case, i.e., 1.4 mmol of tri-n-hexylaluminum, 0.1 mmol vf n-octoxyvanadium oxydichloride, and 0.25 mmol of n-octanol per gram of inorganic oxide, and drying the support at about 250 C. in each case, but using different inorganic oxides as the supports, i.e., silica, magnesium silicate, and.aluminum silicate, respectively. Tllen use each of the catalys-t compositions to prepare polyethylene by the slurry polymerization procedure described above. The melt lndices and NVR values of the polymers are shown in Table VI.
TABLE VI
I
I Run # Inorganic Oxide Support MI2 _ _ __ 14 silica 11.9 1.97 magnesium silicate8.7 1.76 ¦ 16 aluminum silicate11.9 1.66 11 .
39~3 ~ I This example shows that mixtures of inorganic / oxides are also useful as supports for the catalyst / I compositions of the invention and can, in fact, be ¦ par~icularly desirable supports.
! The following two examples demonstrate -that the ¦ reaction of the inorganic oxide with substantially less than a stoichiometric amount of the organometallic compound leads I¦ to the formation of polymers having broader molecular weight 'I distributions when the catalyst compositions are used in ¦ polymerization reactions, and reaction wi~h an amount of . organometallic compound considerably in excess of the stoichiometric amount - although also useful in the preparation of catalyst compositions capable of being l ut.ilized in the production o injection molding-grade 1 po.l.ym~rs - ofEers rlo NVR advantage over th~ use o~ a ~¦ substantlally stoichiometr.ic amount of the organometallic ,j compound.
, EXAMPLE VIII
Prepare three n-C6H13OH/ (n C18 37 2 l Al(C6H13)3/SiO2 catalys-t compositions by the catalyst ¦¦ preparation precedure described above, drying the silica gel at about 200 C. in each case and employing the same arnounts of alcohol and vanadium compound, i.e., 1.0 mmol oE n-hexanol Il and 0.2 mmol of n-octadecoxyvanadium oxydichloride per gram il of silica, but varying the amount of tri-n-hexylaluminum : 1l used. Then use each of the catalyst compositions.to prepare ¦! polyethylene by the slurry polymerization procedure described ¦ above. The yields, melt indices, and NVR values of the polymers are shown in Table VII.
¦ TABLE VII
Il Run # mmol AlR3/g SiO2 Yield MI2 Ij -B 0.8 45 9 1.0 2.54 j 17 1.5 74 9 8.3 1.76 18 2.25 250 g - 1.7 .1 'I -41-i3'3~3 / I
/ ¦ EXAMPLE IX
Prepare three n-C8~ll7O~I/(n C8 17 2 1 Con1p~s~fl'0n~
Al(C2H5)3/SiO2 catalyst-e~m~i~i~ by the ca-talyst preparation procedure described above, drying the silica gel at about 550 C. in each case and employing the same amounts l of alcohol and vanadium compound, i.e., 1.0 mmol of n-octanol i,l and 0.2 mmol of n-octoxyvanadium oxydichloride per gram of ¦ silica, but varying the amount of triethylaluminum used.
! Then use each of the catalyst compositions to prepare polyethylene by the slurry polymerization procedure described above. The yields, melt indices, and NVR values of the polymers are shown in Table VIII.
TABLE VI I I
l __.
Run ~ mmol AlR3/g SiO2 Yield MI2 NVR
C 0.8 48 g ~.S 2.58 D 0.8 55 g 1.4 2.78 19 1.5 320 g 20.~ 1.95 ¦ EXAMPLE: X
Prepare two catalyst compositions by the catalyst preparation procedure described above to -test the utility of dialkoxyvanadium compounds in the practice of the invention.
Use each of the compositions to prepare polyethylene by the sIurry polymerization procedure described above. The yields, ii melt indices, and NVR values of the polymers obtained by the use of each of the catalyst compositions are shown in Table IX.
TABLE IX
_ _ .
Run# Catalyst Composition Yield MI2 NV~
_ C2H5OH/(C2H5O)2VOCl/
l Al(C2H5)3/Mg 152 g 31 2.07 ! l.o mmol 0.2 mmol 1.0 mmol 1 g ¦1 21 C6H13Otl/(cl8H37o)2 ¦ VCl/Al(C6H13)3/Si2 281 g 4.7 1.7 ~¦ 1.0 mmol 0.1 mmol 1.5 mmol 1 g 3~
/ , EXAMPLE XI
/ Prepare a catalyst composition by the catalyst / preparation procedure described above, using silica gel as ¦ the inorganic oxide, drying it at about 200 C., and I sequentially reacting with 1.5 mmol o tri-n-hexylaluminum, ;¦ 0.1 mmol of vanadium oxytrichloride, and l.0 mmol of ~I n-hexanol per gram of silica. When the catalyst composition ¦¦ is used to prepare polyethylene by the slurry polymerization ¦¦ procedure described above, the process xesults in the production of 196 grams of polymer having a melt index of ¦1 12.5 and an NVR value of 1.86.
EXAMPLE XIII
Prepare three catalyst compositions by the catalyst preparation procedure described above, except or using no alcohol in the preparatiorl Oe the first compos~tion. In e~ch case, employ SiO2 as the inorganic oxide, triethylaluminum as I the vanadium compound, and n-hexanol as the alcohol, when j employed, and dry the support at about 250 C. Use each of ¦ the catalyst compositions to prepare polyethylene by the ~¦ slurry polymerization procedure described above. The number I of mmols of triethylaluminum, vanadium tetrachloride, and n-hexanol employed per gram of silica in the production of the catalyst compositions, and the yields, melt indices, and NVR values of the polymers are shown in Table X.
TABLE X
: I . `.
¦ Run # Catalyst Compositlon Yield MI2 NVR
_ ¦ ~ vcl4/Al(C2H5)3 : 1l /SiO2 2366 9 0.3 2.34 0.2 1.5 : 22 C6Hl3oH/vcl4 : I /Al(C2H5)3/sio2227 g 1.7 2.17 0.15 0.05 1.4 23 C6Hl3OH/vcl4/Al(c2H5)3 /SiO2 1007 g 0.4 2.01 0.5 0.2 1.5 l _ _ _ _ _ _ ~ 43_ 3~3~3~ ~1~
Examples X-XIII demonstrate the utility of vanadium conl~oullds other than alkoxyvanadium oxydichlorides in the practice oE the invention.
¦I EXA~PLE XIV
j 6 130H/(C18~370)VOC12/Al(C6H13) 3/sio ¦I catalyst composition by the catalyst preparation procedure described above employing 1.5 mmol of tri-n-hexylaluminum, 0.1 mmol of n-octadeco~yvanadium~ oxydichloride, and 1.0 mrnol of n-hexanol per gram of silica. For comparative ,I purposes, prepare five other catalyst compositions from the ¦¦ same amounts of the same inyredients, and use the same drying !I temperature for the silica as was used in the preparation of Il the first of the compositions, but varyiny the order of ¦¦ addition of the catalyst components to determine the criticallty o~ that ord~r o addition. Therl u6e each oE the I catalyst compos:itions to prepare pol~ethylene by ~he slurry ~! polymerization procedure described above. The catalyst ~¦ compositions and the melt indices and NVR values of the i¦ polymers are shown in Table XI, which, llke the earlier Tables, lists the catalyst components in the reverse order of ¦ addition, i.e , the last-added component beiny the first list~d as one reads from left to riyht.
I¦ TABLE XI
I
~ Run ~ Catalyst Composition MI2 NVR
, : _ ¦ 24C6H130H/(ClgH370)VOC12/Al(C6~13)3 2 ( 6Hl3)3/c6Hl3oH/(clgH37o)vocl2/sio2 -- 2.51 ,I G6 13oH/Al(c6Hl3j3/(clgH37o)vocl2/siQ2 ~~ 2.81 I ¦ H~ (Cl8H37o)vocl2/c6Hl3oH/Al(c6 13 3 2 2.44 I(~l8H37o~vocl2A~(c6Hl3)3/c6Hl3 / 2 2.88 ( 6~l3)3/~cl8H37o)vocl2/c6~l3oH/sio2 1.5 2.38 I
As demonstrated above, catalyst compositions prepared from the same components as the catalyst l compositions of the invention do not have the same i effectiveness in narrowing the molecular welght distributions ., Il, j -44-/~ ~X4:~3'~t3~3~j .
of polymers prepared in their presence when the catalyst components are combined in a different order.
Each of the preceding examples illustrates the utility of catalyst compositions of the invention in slurry polymerization processes. The following -two examples demonstrate their utility in gas-phase polymerization reactions.
EXAMPLE XV
Use the catalyst composition of Example I, Run # 3, to prepare polyethylene by the laboratory gas-phase polymerization procedure described above. The reaction temperature employed for the polymerizations and the melt indices and NVR values of the product are shown in Table XII.
There was no evidence of reactor fouling.
TA~LE XII
E~un ~ Temperature MI2 NVR
_ 99 C. 40 2.08 26 99 C. 7 2.02 27 88 C. 6 2.14 28 88 C. 3 2.16 I :
¦ EXAMPLE XVI
~se the catalyst composition of Example VIII, Run ¦ #17, to prepare polyethylene by the laboratory gas-phase polymeri~ation procedure described above. The ~elt indices ¦ and NVR values of the products are shown in Table XIII.
¦~ ~There was no evidence of reactor fouling.
TABLE XIII
I ~
Run # MI2 NVR
l : - , _.
29 10.8 1.89 24.l 1.88 31 7.7 1.~5 I _ _ !
1,l ll -A5~
4~
1~i39~3~i /!1 ~ EXAMPLE K
I An attempt was made to essentially repeat Example '¦ III of U.S. Pat. No. 4,232,140 using the laboratory gas-phase polymerization method described above with Ort's catalyst and CFCl3 promoter, operating the equipment contlnuously 24 hours a day. After two days, and before the reaction had lined out Il sufficiently to get a good sample of the desired product for il comparison with the products made by the catalysts of this ¦¦ invention, the reactor became inoperable. After the reaction ¦I system had been shut-down, the reactor was opened. The ~¦ reactor walls and distribution plate were found to be fouled !l (coated with polyrner) to the extent that normal fluidization ¦¦could not be maintained.
The reactor was thoroughly clearled, al~d the attempt rep~a~ed. ThLs t;im~, ~h~ reactor "ouled out" in about o~le ¦¦clay. A third att~mpt to run this catalyst and CE'C13 promoter on a continuous basis was similarly unsuccessful. This l example shows that long term operability of a gas-phase ! fluidized bed depends upon proper choice of catalyst and 'il promoter.
The foregoing examples illustrate the utility of thc invcntiorl in tl~e ~re~a~ation vf hig~l dellsity polyct~lylcn~
which typically have dcnsities of at least 0.~65 g/cc. Th~
following exampl~s illustrate its utility in the preparation ~ of-~h~y~e~e polymers having lower densities.
;: ¦! EXAMPLE XVII
j Prepare two catalyst compositions by the catalyst preparation procedure described above, using magnesia as the ¦ inorganic oxlde in each case, drying it at about 200 C., and ¦ sequentially reacting it with 1.4 mmol of triethyaluminum, 0.2 mmol of an alkoxyvanadium oxydichloride, and 1.0 mmol of Il an alkanol per gram of magnesia. Then use each of the ¦Icatalyst composi-tions to prepare an ethylene copolymer by the ~¦slurry polymerization procedure described above, employing 30 cc o~ liquid butene-l as the comonomer in each case. The catalyst compositions and the melt indices, NVR values, and Il / I densities of the polymer are shown in Table XIV.
/ ¦ T~BLE XIV
/ il Run ~ Catalyst Composition MI2 NVR Density ~' i ¦ 32 C2H5H/(C2H5)VC 2/ 20 2.00 0.960 A1(C21t5)3/MCJo 33 C4HgH/(C~H9)vcl2/ 1.4 1.95 0.956 ¦ Al ( C 2 H 5 ) 3/Mg EXAMPLE XVIII
Prepare two catalyst compositions by the catalyst preparation procedure described above, using silica as the inorganic oxide in each case, drying it at about 550 C., and ~qu~ntlally reacti~lg lt with 1.4 mmol of triettlyla:lum.inllm, 0.2 mmol of an alkoxyvanadiwn oxydichloride, and 1.0 mmol o~
an alkanol per gram of silica. Then use each of the catalyst compositions to prepare an ethylene copolymer by the slurry polymerization procedure described above, employing 40 cc of liquid butene-l as the comonomer in each case. The CO~o~ o5~'~;0 n catalyst e~m~t-i~n a~d -the melt lndices, NVR values, and densities of the polymers are shown in Table XV.
TABLE XV
Run # Catalyst Composition MI2 NVR Density _ .
34 C8H17OH/~c8Hl7o)vocl2/ 52.6 2.05 0.948 Al(c2H5)3/sio2 CH3H/(C18H37)VC12/ 17.3 1.85 0.952 Al(c2H5~3/slo2 ~ ~ , , __ _. _ ¦ EXAMPLE XIX
il Prepare two catalyst compositions by -the.catalyst ¦ preparation procedure described above, using alumina as the Il inorganic oxide in each-case, drying it at about 550 C~ in jl the case of the catalyst composition to be used in ~un # 36 I; and at about 500 C. in the case of the catalyst composition ,1 -47~
/ ¦ to be used in Run #37, and sequentially reacting it with l.S
/ I mmol of trialkylaluminum, 0.2 mmol of n-octoxyvanadium / ¦ oxydichloride, and l.0 mmol of n-octanol per gram of ~ 11 alumina. Then use each of the catalyst compositions to J ~l prepare an ethylene copolymer by the slurry polymerization ¦ procedure described above, employing 40 cc of liquid butene-l as the comonomer in each case. The catalyst compositions and the melt indices, NVR value and densities of the polymers are show in Table XVI.
l , TABLE XVI
I .
l Run # Catalyst Composition MI2 NVR Density i 6 C~lll7o~l/(cg~ll7o)vocl2/
~1(C2~ls)3/A12 3 16.3 I.75 0.955 37 C8~l17~l/(c~Jll7~jvocl2/
Al(C6~ll3)3/~l2o3 67.8 1.63 0.9S5 l _ ¦ EXAMPLE XX
j, ~se the catalyst composition of Example XIII, Run #23, to prepare an ethylene copolymer by the slurry polymerization procedure described above, employing 100 cc of liquid butene-l as the comonomer. The process results in the production of 1007 grams of an ethylene/butene-l copolymer having an NVR value of 2.01 and a density of 0.937.
l EXAMPLE XXI
¦ I Use the catalyst of Example XI to prepare an ~¦ ethylene copolymer by the slurry polymerization procedure I described above, utilizing 40 cC of liquid butene-l as the ¦ comonomer. The process results in the production of 283 grams of an ethylene/butene-l copolymer having an MI2 of 11.4 and an NVR value of 2.17.
EXAMPLE XXII
A batch of catalyst having the composition 1.4 mmol ¦ triethylaluminum, 0.2 mmol VCl4, 0.5 mmol n-octanol per gram Sio2 was prepared as a dry powder according to the general ~ ~ i39~
~/ I procedure of Rogers, U.S. 4,426,317. Gas phase ¦ copolymerizatioll was carried out in a small pilot plant Il similar in design to the laboratory gas phase reactor except ¦¦ that there was no separator in the gas recycle line. The t~
reactor had a reaction zone 30 cm in diameter, about 2 m tall. This run was conducted at 2.0 ~IPa and~ e}~ees C
I '~
average bed temperature with a recycle gas flow of about 1100 i kg/hr which gave a gas velocity ln the bed of about 30 cm/sec. The recycle gas stream consisted essentially of 84.4~ ethylene, 3.8% ~ydrogen, 9.3~ butene-l, and 2.5~
nitrogen. Catalyst was added with nitrogen to the fluidized ¦ bed at an average ra-te of 7.5 cc/hr, triethylaluminum ~TEA) ~'1 was added as a 10% solution in hexane at a rate of 4.9 cc/hr, !! and chloroform was added at a rate of 1.4 cc/hr. A film-grade ¦¦ polyrner having a melt index of 1.4, a density of 0.934, and a i¦ total ash content of 600 ppm was produced at an average rate P
¦¦ of about 7 kg/hr during 8 hours oE steady op~ration.
I¦ EXAMPL~ L
¦j ~t the conclusion of Example XXII, the hydrogen feed is discontinued while everything else is maintained ¦ essentially unchanged. Gradually, the hydrogen/ethylene li ratio drops, as determined by an on-line gas analyzer, as ¦~ recycle gases are lost from the reaction zone through purge Il to the instruments and by being removed with the polyethylene ¦¦ product, with no fresh hydrogen being added to the make-up gases. As the hydrogen level in the recycle gas decreases, il the polymer melt index drops until it is unmeasurably low.
j The polymerization rate, as determined by ethylene uptake and j by product removal from the reaction zone, is unchanged within experimental error. Thcre is no external evidence of reactor fouling. Hydrogen flow is then restarted, and the original hydrogen/ethylene ratio re-established. Within 18 hours, the melt index is again 1.4 and the polymer is again useful for fil~
r;,i 11 '3~3~;
The chloroform feed is then discontinued, all other ;
variables being held as constant as possible. Gradually, the CI~C13/V ratio decreases as the CIIC13 concentration in the recycle gas becomes lower due to loss of recycle gas from the system and the make-up gases being promoter-free. There is no significant change in the melt index of the polymer, but the polymerization rate drops and the ash content of the polymer increses to about 3000 ppm, too high for good quality film. The chloroform feed is then restarted at its original t feed rate. Polymerization rate picks up immediately, as judged from an increase in both bed temperature and polymer powder production, and reaches a level of about 10 kg/hr, after which the rate slowly declines and lines out at about 7 kg/hr. About 36 hours aEter chloroorm is readmitted to the reaction, ~he reactlorl àncl polym~r are restab:Lized at the~
original conditions and the polymer is again useEul for film.
Then the triethylaluminum feed is stopped, all other variables being held as constant as possible. The polymerization rate begins to decrease, slowly at first, and then rapidly. The ash content of the polymer increases correspondingly. When the polymerization rate reaches about 1 kg/hr, the reaction is terminated intentionally, and the reactor opened for inspection. There is no visible coating or fouling on the distribution plate or reactor walls.
This example illustrates ~n~trialkylaluminum, chloroform and hydrogQn, in the proper proportions, are essential to useful practice of this invention.
EXA~IPLE XXIII
The general procedure of Example XXII was repeated except that the catalyst had the formulation of the catalyst of Example XIII run 22 and propylene was the colnonomer.
Polymerization pressure was about 2.1 MPa, and average bed temperatures were in the range of 78 - 82 degrees C. The other run conditions and corresponding polymer properties obtained are given in Table XV. Each run in Table XV
1,1 ,1 -50-12~;.1'3')~
I represents a different condition of reasonably stable, ¦ operation during a 7-day period of continuous operation. At ¦ the end of the 7-day period, the reactor was shut down by ¦j failure of the polymer withdrawal system. There was no ¦¦ evidence of fouling of reactor walls or the distribution plate.
TABLE XV
Il _ I
ll Run # 38 39 40 41 42 l l . ~ l Recycle gas composition:
Ethylene 61.663.0 68.0 58.9 61.0 ! % Hydrogen 1.1 1.5 1.3 1.0 1.0 % Propylene 12.411.4 7.4 11.9 11.4 % Nitrogen 24.924.1 23.3 28.2 26.6 ¦ % Chloroform 0.007 0.00980.0073 0.012 0.015 I
Flow Rates:
¦ Catalys~ (cc/hr) 5.3 4.6 2.6 3.3 3.8 TE~ (cc/hr) 3.1 3.0 3.7 3.6 3.9 Production (kg/hr) 2.1 3.4 1.5 2.0 2.2 Polymer properties:
MI (dg/min) 1.1 0.87 0.76 0.90 0.48 l Density (g~cc) 0.916 0.917 0.920 0.919 0.915 ¦ Ash, ppm 390 367 340 347 ¦ V residue, ppm 1.6 0.9 1.1 1.1 1.1 _ EXAMPLE XXIV
Three samples of narrow molecular weight I ¦ distribution ethylene copolymers were made in a larger ¦ gas-phase fluidized-bed pilot plant polymerization system.
The reaction zone was 46 cm in diameter and about 3 m tall.
¦l It was topped by a disengaging zone of 92 cm diamerer. Gas ~¦ recycle piping led from the disengaging zone through a heat exchanger and recycle gas blower to the bottom of the reactor. A distribution plate at the bottom of the reactor ,I served to disperse or distribute the gas evenly at the bottom ¦¦ of the bed. Gas analyzers monitored the gas composition of !~ the recycle system and, via suitable instrumentation~
~¦ automatically adjusted flows of Eeed streams to keep th~ 'J~
Il I
~ `51-33~36 ~ 11 composition constant Catalyst was fed directly to the bed with an automatic catalyst feeder using nitrogen as the motive gas to convey the ca-talyst into the bed.
Triethylaluminum ~TEA) was pumped directly into the bed.
Polymer powder was automatically withdrawn to maintain a constant inventory of powder in the reactor. Eor all three samples, reaction pressure was about 3.5 MPa, average bed temperature ws about 92 degrees C, and the recycle gas rate was about 4525 kg/hr, which gave a gas velocity in the bed of crf~ .
abou-t 30 ~/sec. Average reaction conditions during the time each sample was collected and results for each sample are given in Table XVI.
Catalysts for these runs were made essentially as taught by Rogers in U.5. 4,~26,317. For runs 43 and 44, the cataLyst contpo5ition was 1.5 mmol tri-n-hcxylalum:irlulll, 0.1 rllmol n-octad~cyloxyvancldLurn oxydichloride and 1.0 mmol n-hexanol per gram of dry silica support. For run 45, the catalyst had the composition of 2.25 mmol tri-n-hexylaluminum, 0.2 mmol n-octadecyloxyvanadium oxydichloride and 1.0 mmol n-hexanol per gram of dry silica.
There was no evidence of reactor fouling after any of the runs.
, i3~396 ~ ~ ~ TABLE XVI
. ~ igl ~ _ .
¦ Run ~ 43 44 45 Recycle Gas Composition:
Nitrogen 5.6 5.9 6.8 I ~ Ethylene 86.185.1 84.8 i % ~ydrogen 4.4 5.1 5.3 , % Propylene 3.9 3.9 3.1 ¦ ~ Chloroform 0.0700.085 0.080 Other Poly~erization data:
Al/V ratio 42 29 26 ~/3/~eHe~- ratio 123 305 112 Production (kg/hr) 15 13 13 Polymer properties:
I MI (dg/min) 2.2 q.5 2.1 ~ Density (y/cc) 0.9530.954 0.9Sq I ~h,ppm 702 699 323 V residue, ppm 2.9 3.1 2.9 _ EXAMPLE XXV
A commercial gas-phase fluidized-bed polyme~rization ¦ is carried out in a polymerization system of the same general ¦ description as the pilot plant of example XXIV. `However, the reaction zone is 3.6 m in diameter and about 15 m tall.
Recycle gas rate is sufficient to give a gas velocity in the bed of about 30 cm/sec The polymerization is conducted at 3.5 MPa pressure and 93 degrees C average bed temperature with a feed stream targets of 6.0 ~ ~ nitrogen, 85.0 ethylene, 3.9 % propylene, 5.1 ~ hydrogen, and 0.07 ~
I chloroform. The catalyst has the formulation 1.4 mmol ¦¦ triethylaluminum, 0.1 mmol undecyloxyvanadium oxydichloride, ¦ 1.0 mmol n-octanol and is made in commerclal batches of 4S0 ~ kg each. The Al/V ratio during polymerization varies ¦~ slightly as monomer purity varies, but is in the range of 10 Il to 30.
¦¦ The polymer, producted at a rate of about 8.5 me-tric tons per hour, is an injection molding grade, has an _- !
3~3~3~
average melt inde~ of 5, an average density of Q.954, and an NVR of 1.9 plus or minus 0.1 This product is made in commercial runs of two weeks or longer without evidence of reactor fouling.
Similar results in the narrowing of the molecular weight distributions of ethylene polymers are obtained when the examples are repeated except that the catalyst components, component proportions, comonomers, comonomer proportions, and/or polymerizatlon conditions specified in the examples are replaced with catalyst components, component proportions, comonomers, comonomer proportions, and/or polymerization conditions -taught to be their equiva~ents in the specification.
While the present invention has been described herein with refcrellce to p~rticul~r emodiments thereof, a latitude o modiEication, various changes and substitutions are intencled in the foregoing disclosure, and it will be appreciated that in some instances some features of the invention will be employed without a corresponding use of other features without departing from the scope of the lnvention as set forth.
!l i ii ' -54-1!
399 Ei 11 I The preceding example and the following three l examples show that the use of different inorganic oxides, ¦ different alkoxyvanadium compounds, and different alcohols I which may or may not have the same chain length as the alkoxy l groups of the vanadlum compounds employed, as well as the use of diEferent support drying temperatures, are permissable within the scope of the invention and lead to the formation .
! of catalyst compositions that can be used to prepare polymers ! having narrow-to-intermediate molecular weight distributions.
l These examples also show that, in general, narrower molecular ¦¦ weight distributions are obtained when the catalysts used in the preparation of ethylene polymers are formed by the use of supports that have been dried at the higher temperatures within the preEerred range of drying temperatures taught in , the speciflcation.
EXAMPL~ tV
I Prepare three n-C8~l17~l/(n C8~17 ) 2 Al(C2H5)3/SiO2 catalyst compositions by the catalyst ¦preparation procedure described above, employing the same amounts of ingredients in each case, i.e., 1.4 mmol oE
triethylaluminum, 0.2 mmol of n-octoxyvanadium oxydichloride, and 1.0 mmol of n-octanol per gram of silica, but using . different dryiny temperatures for the silica used in ¦producing each of the compositions, i.e., 200 C., 350 C., ¦and 550 C., respec-tively.` Then use each of the catalyst ,I!compositions to prepare polyethylene by the slurry ,¦polymerization procedure described above. The yields, melt indices, and NVR values of the polymers are shown in Table IIIII.
TABLE III
I,Run # Support Drying Temp. Yield MI2 NVR
il7 200 C. 55 g 1.8 2.32 8 350 C. l46 g 2.1 2.~1 ilg s5oo C. 320 g 20.2 l.9S
~ 38-39'36 I EXAMPLE V
I Prepare two n-c~ 7oH/(n-c~Hl7o)vocl2/Al(c2~l5)3/
~¦ A12O3 catalyst compositions by the catalyst preparation ¦ procedure described above, employing the same amounts of ¦ ingredients in each case, i.e., 1.4 mmol of triethylaluminum, 1 0.2 mmol of n-octoxyvanadium oxydichloride, and 1.~ mmol of ¦ n-octanol per gram of alumina, but using~a drying temperature of about 200 C. for the alumina used in producing the first of the compositions and a drying temperature of about 550 C.
for the alumina used in producing the second of the compositions. Then use each of the catalyst compositions to Il prepare polyethylene by the slurry polymerization procedure ¦I described above. The yields, melt indices, and NVR values of ~ the polymers are shown in Table IV.
I T~\BLE IV
l _ _ ~¦ Run # Support Drying Temp. Yield ~I2 NVR
200 C. 47 9 6.9 2.16 11 550 C. 83 g 11.6 1.65 ¦ EXAMPLE VI
~ pare two nac8~ll7oH/(n-c8Hl7o)~ocl2/A ( 6 13 3 A12O3 catalyst compositions by the catalyst preparation jl procedure described above, employing the same amounts of ¦ ingredients in each case, i.e., 1.5 mmol of tri-n-hexylaluminum, 0.2 mmol of n-octoxyvanadium oxydichloride, and 1.0 mmol of n-octanol per gram of alumina, but using a drying temperature of about 200 C. for the alumina used in producing the first of the compositions and a drying temperature of about 500 C. for the alumina used in i producing the second of the compositions. Then use each of the catalyst compositions to prepare polyethylene by the slurry polymerization procedure described above. The yields melt indices, and NVR values of the polymers are shown in Table V.
!~
~1 ~39~
;3~:396 ~I ill ¦l TABLE V
11 ;I,i / IlRun ~ Support Drying Ternp. Yield MI2 NVR
~ _ - ~h 12 200C. 48 g - 1.91 , , 13 500 C. 355 9 18.6 1.67 As demonstrated above, particularly when ~12 of this example is compared with Run ~10 of the preceding example, the substitution of a higher trialkylaluminum for a lower trialkylaluminum in preparins -the catalyst compositions of the invention can lead to a narrowing of the molecular weight distribution of polymers formed in the presence oE the catalyst compositions when all ~ther factors are substantially constant.
EXAMPL~ VII
Prepare three n-c8~1L7o~l/(n-c8Ell7o)vocl2/
"p o~ 'vn ~
Al~C6lll3)3/inorganic oxide catalyst-eem~e~tio~ by the catalyst preparation procedure described above, employing the same amounts of ingredients in each case, i.e., 1.4 mmol of tri-n-hexylaluminum, 0.1 mmol vf n-octoxyvanadium oxydichloride, and 0.25 mmol of n-octanol per gram of inorganic oxide, and drying the support at about 250 C. in each case, but using different inorganic oxides as the supports, i.e., silica, magnesium silicate, and.aluminum silicate, respectively. Tllen use each of the catalys-t compositions to prepare polyethylene by the slurry polymerization procedure described above. The melt lndices and NVR values of the polymers are shown in Table VI.
TABLE VI
I
I Run # Inorganic Oxide Support MI2 _ _ __ 14 silica 11.9 1.97 magnesium silicate8.7 1.76 ¦ 16 aluminum silicate11.9 1.66 11 .
39~3 ~ I This example shows that mixtures of inorganic / oxides are also useful as supports for the catalyst / I compositions of the invention and can, in fact, be ¦ par~icularly desirable supports.
! The following two examples demonstrate -that the ¦ reaction of the inorganic oxide with substantially less than a stoichiometric amount of the organometallic compound leads I¦ to the formation of polymers having broader molecular weight 'I distributions when the catalyst compositions are used in ¦ polymerization reactions, and reaction wi~h an amount of . organometallic compound considerably in excess of the stoichiometric amount - although also useful in the preparation of catalyst compositions capable of being l ut.ilized in the production o injection molding-grade 1 po.l.ym~rs - ofEers rlo NVR advantage over th~ use o~ a ~¦ substantlally stoichiometr.ic amount of the organometallic ,j compound.
, EXAMPLE VIII
Prepare three n-C6H13OH/ (n C18 37 2 l Al(C6H13)3/SiO2 catalys-t compositions by the catalyst ¦¦ preparation precedure described above, drying the silica gel at about 200 C. in each case and employing the same arnounts of alcohol and vanadium compound, i.e., 1.0 mmol oE n-hexanol Il and 0.2 mmol of n-octadecoxyvanadium oxydichloride per gram il of silica, but varying the amount of tri-n-hexylaluminum : 1l used. Then use each of the catalyst compositions.to prepare ¦! polyethylene by the slurry polymerization procedure described ¦ above. The yields, melt indices, and NVR values of the polymers are shown in Table VII.
¦ TABLE VII
Il Run # mmol AlR3/g SiO2 Yield MI2 Ij -B 0.8 45 9 1.0 2.54 j 17 1.5 74 9 8.3 1.76 18 2.25 250 g - 1.7 .1 'I -41-i3'3~3 / I
/ ¦ EXAMPLE IX
Prepare three n-C8~ll7O~I/(n C8 17 2 1 Con1p~s~fl'0n~
Al(C2H5)3/SiO2 catalyst-e~m~i~i~ by the ca-talyst preparation procedure described above, drying the silica gel at about 550 C. in each case and employing the same amounts l of alcohol and vanadium compound, i.e., 1.0 mmol of n-octanol i,l and 0.2 mmol of n-octoxyvanadium oxydichloride per gram of ¦ silica, but varying the amount of triethylaluminum used.
! Then use each of the catalyst compositions to prepare polyethylene by the slurry polymerization procedure described above. The yields, melt indices, and NVR values of the polymers are shown in Table VIII.
TABLE VI I I
l __.
Run ~ mmol AlR3/g SiO2 Yield MI2 NVR
C 0.8 48 g ~.S 2.58 D 0.8 55 g 1.4 2.78 19 1.5 320 g 20.~ 1.95 ¦ EXAMPLE: X
Prepare two catalyst compositions by the catalyst preparation procedure described above to -test the utility of dialkoxyvanadium compounds in the practice of the invention.
Use each of the compositions to prepare polyethylene by the sIurry polymerization procedure described above. The yields, ii melt indices, and NVR values of the polymers obtained by the use of each of the catalyst compositions are shown in Table IX.
TABLE IX
_ _ .
Run# Catalyst Composition Yield MI2 NV~
_ C2H5OH/(C2H5O)2VOCl/
l Al(C2H5)3/Mg 152 g 31 2.07 ! l.o mmol 0.2 mmol 1.0 mmol 1 g ¦1 21 C6H13Otl/(cl8H37o)2 ¦ VCl/Al(C6H13)3/Si2 281 g 4.7 1.7 ~¦ 1.0 mmol 0.1 mmol 1.5 mmol 1 g 3~
/ , EXAMPLE XI
/ Prepare a catalyst composition by the catalyst / preparation procedure described above, using silica gel as ¦ the inorganic oxide, drying it at about 200 C., and I sequentially reacting with 1.5 mmol o tri-n-hexylaluminum, ;¦ 0.1 mmol of vanadium oxytrichloride, and l.0 mmol of ~I n-hexanol per gram of silica. When the catalyst composition ¦¦ is used to prepare polyethylene by the slurry polymerization ¦¦ procedure described above, the process xesults in the production of 196 grams of polymer having a melt index of ¦1 12.5 and an NVR value of 1.86.
EXAMPLE XIII
Prepare three catalyst compositions by the catalyst preparation procedure described above, except or using no alcohol in the preparatiorl Oe the first compos~tion. In e~ch case, employ SiO2 as the inorganic oxide, triethylaluminum as I the vanadium compound, and n-hexanol as the alcohol, when j employed, and dry the support at about 250 C. Use each of ¦ the catalyst compositions to prepare polyethylene by the ~¦ slurry polymerization procedure described above. The number I of mmols of triethylaluminum, vanadium tetrachloride, and n-hexanol employed per gram of silica in the production of the catalyst compositions, and the yields, melt indices, and NVR values of the polymers are shown in Table X.
TABLE X
: I . `.
¦ Run # Catalyst Compositlon Yield MI2 NVR
_ ¦ ~ vcl4/Al(C2H5)3 : 1l /SiO2 2366 9 0.3 2.34 0.2 1.5 : 22 C6Hl3oH/vcl4 : I /Al(C2H5)3/sio2227 g 1.7 2.17 0.15 0.05 1.4 23 C6Hl3OH/vcl4/Al(c2H5)3 /SiO2 1007 g 0.4 2.01 0.5 0.2 1.5 l _ _ _ _ _ _ ~ 43_ 3~3~3~ ~1~
Examples X-XIII demonstrate the utility of vanadium conl~oullds other than alkoxyvanadium oxydichlorides in the practice oE the invention.
¦I EXA~PLE XIV
j 6 130H/(C18~370)VOC12/Al(C6H13) 3/sio ¦I catalyst composition by the catalyst preparation procedure described above employing 1.5 mmol of tri-n-hexylaluminum, 0.1 mmol of n-octadeco~yvanadium~ oxydichloride, and 1.0 mrnol of n-hexanol per gram of silica. For comparative ,I purposes, prepare five other catalyst compositions from the ¦¦ same amounts of the same inyredients, and use the same drying !I temperature for the silica as was used in the preparation of Il the first of the compositions, but varyiny the order of ¦¦ addition of the catalyst components to determine the criticallty o~ that ord~r o addition. Therl u6e each oE the I catalyst compos:itions to prepare pol~ethylene by ~he slurry ~! polymerization procedure described above. The catalyst ~¦ compositions and the melt indices and NVR values of the i¦ polymers are shown in Table XI, which, llke the earlier Tables, lists the catalyst components in the reverse order of ¦ addition, i.e , the last-added component beiny the first list~d as one reads from left to riyht.
I¦ TABLE XI
I
~ Run ~ Catalyst Composition MI2 NVR
, : _ ¦ 24C6H130H/(ClgH370)VOC12/Al(C6~13)3 2 ( 6Hl3)3/c6Hl3oH/(clgH37o)vocl2/sio2 -- 2.51 ,I G6 13oH/Al(c6Hl3j3/(clgH37o)vocl2/siQ2 ~~ 2.81 I ¦ H~ (Cl8H37o)vocl2/c6Hl3oH/Al(c6 13 3 2 2.44 I(~l8H37o~vocl2A~(c6Hl3)3/c6Hl3 / 2 2.88 ( 6~l3)3/~cl8H37o)vocl2/c6~l3oH/sio2 1.5 2.38 I
As demonstrated above, catalyst compositions prepared from the same components as the catalyst l compositions of the invention do not have the same i effectiveness in narrowing the molecular welght distributions ., Il, j -44-/~ ~X4:~3'~t3~3~j .
of polymers prepared in their presence when the catalyst components are combined in a different order.
Each of the preceding examples illustrates the utility of catalyst compositions of the invention in slurry polymerization processes. The following -two examples demonstrate their utility in gas-phase polymerization reactions.
EXAMPLE XV
Use the catalyst composition of Example I, Run # 3, to prepare polyethylene by the laboratory gas-phase polymerization procedure described above. The reaction temperature employed for the polymerizations and the melt indices and NVR values of the product are shown in Table XII.
There was no evidence of reactor fouling.
TA~LE XII
E~un ~ Temperature MI2 NVR
_ 99 C. 40 2.08 26 99 C. 7 2.02 27 88 C. 6 2.14 28 88 C. 3 2.16 I :
¦ EXAMPLE XVI
~se the catalyst composition of Example VIII, Run ¦ #17, to prepare polyethylene by the laboratory gas-phase polymeri~ation procedure described above. The ~elt indices ¦ and NVR values of the products are shown in Table XIII.
¦~ ~There was no evidence of reactor fouling.
TABLE XIII
I ~
Run # MI2 NVR
l : - , _.
29 10.8 1.89 24.l 1.88 31 7.7 1.~5 I _ _ !
1,l ll -A5~
4~
1~i39~3~i /!1 ~ EXAMPLE K
I An attempt was made to essentially repeat Example '¦ III of U.S. Pat. No. 4,232,140 using the laboratory gas-phase polymerization method described above with Ort's catalyst and CFCl3 promoter, operating the equipment contlnuously 24 hours a day. After two days, and before the reaction had lined out Il sufficiently to get a good sample of the desired product for il comparison with the products made by the catalysts of this ¦¦ invention, the reactor became inoperable. After the reaction ¦I system had been shut-down, the reactor was opened. The ~¦ reactor walls and distribution plate were found to be fouled !l (coated with polyrner) to the extent that normal fluidization ¦¦could not be maintained.
The reactor was thoroughly clearled, al~d the attempt rep~a~ed. ThLs t;im~, ~h~ reactor "ouled out" in about o~le ¦¦clay. A third att~mpt to run this catalyst and CE'C13 promoter on a continuous basis was similarly unsuccessful. This l example shows that long term operability of a gas-phase ! fluidized bed depends upon proper choice of catalyst and 'il promoter.
The foregoing examples illustrate the utility of thc invcntiorl in tl~e ~re~a~ation vf hig~l dellsity polyct~lylcn~
which typically have dcnsities of at least 0.~65 g/cc. Th~
following exampl~s illustrate its utility in the preparation ~ of-~h~y~e~e polymers having lower densities.
;: ¦! EXAMPLE XVII
j Prepare two catalyst compositions by the catalyst preparation procedure described above, using magnesia as the ¦ inorganic oxlde in each case, drying it at about 200 C., and ¦ sequentially reacting it with 1.4 mmol of triethyaluminum, 0.2 mmol of an alkoxyvanadium oxydichloride, and 1.0 mmol of Il an alkanol per gram of magnesia. Then use each of the ¦Icatalyst composi-tions to prepare an ethylene copolymer by the ~¦slurry polymerization procedure described above, employing 30 cc o~ liquid butene-l as the comonomer in each case. The catalyst compositions and the melt indices, NVR values, and Il / I densities of the polymer are shown in Table XIV.
/ ¦ T~BLE XIV
/ il Run ~ Catalyst Composition MI2 NVR Density ~' i ¦ 32 C2H5H/(C2H5)VC 2/ 20 2.00 0.960 A1(C21t5)3/MCJo 33 C4HgH/(C~H9)vcl2/ 1.4 1.95 0.956 ¦ Al ( C 2 H 5 ) 3/Mg EXAMPLE XVIII
Prepare two catalyst compositions by the catalyst preparation procedure described above, using silica as the inorganic oxide in each case, drying it at about 550 C., and ~qu~ntlally reacti~lg lt with 1.4 mmol of triettlyla:lum.inllm, 0.2 mmol of an alkoxyvanadiwn oxydichloride, and 1.0 mmol o~
an alkanol per gram of silica. Then use each of the catalyst compositions to prepare an ethylene copolymer by the slurry polymerization procedure described above, employing 40 cc of liquid butene-l as the comonomer in each case. The CO~o~ o5~'~;0 n catalyst e~m~t-i~n a~d -the melt lndices, NVR values, and densities of the polymers are shown in Table XV.
TABLE XV
Run # Catalyst Composition MI2 NVR Density _ .
34 C8H17OH/~c8Hl7o)vocl2/ 52.6 2.05 0.948 Al(c2H5)3/sio2 CH3H/(C18H37)VC12/ 17.3 1.85 0.952 Al(c2H5~3/slo2 ~ ~ , , __ _. _ ¦ EXAMPLE XIX
il Prepare two catalyst compositions by -the.catalyst ¦ preparation procedure described above, using alumina as the Il inorganic oxide in each-case, drying it at about 550 C~ in jl the case of the catalyst composition to be used in ~un # 36 I; and at about 500 C. in the case of the catalyst composition ,1 -47~
/ ¦ to be used in Run #37, and sequentially reacting it with l.S
/ I mmol of trialkylaluminum, 0.2 mmol of n-octoxyvanadium / ¦ oxydichloride, and l.0 mmol of n-octanol per gram of ~ 11 alumina. Then use each of the catalyst compositions to J ~l prepare an ethylene copolymer by the slurry polymerization ¦ procedure described above, employing 40 cc of liquid butene-l as the comonomer in each case. The catalyst compositions and the melt indices, NVR value and densities of the polymers are show in Table XVI.
l , TABLE XVI
I .
l Run # Catalyst Composition MI2 NVR Density i 6 C~lll7o~l/(cg~ll7o)vocl2/
~1(C2~ls)3/A12 3 16.3 I.75 0.955 37 C8~l17~l/(c~Jll7~jvocl2/
Al(C6~ll3)3/~l2o3 67.8 1.63 0.9S5 l _ ¦ EXAMPLE XX
j, ~se the catalyst composition of Example XIII, Run #23, to prepare an ethylene copolymer by the slurry polymerization procedure described above, employing 100 cc of liquid butene-l as the comonomer. The process results in the production of 1007 grams of an ethylene/butene-l copolymer having an NVR value of 2.01 and a density of 0.937.
l EXAMPLE XXI
¦ I Use the catalyst of Example XI to prepare an ~¦ ethylene copolymer by the slurry polymerization procedure I described above, utilizing 40 cC of liquid butene-l as the ¦ comonomer. The process results in the production of 283 grams of an ethylene/butene-l copolymer having an MI2 of 11.4 and an NVR value of 2.17.
EXAMPLE XXII
A batch of catalyst having the composition 1.4 mmol ¦ triethylaluminum, 0.2 mmol VCl4, 0.5 mmol n-octanol per gram Sio2 was prepared as a dry powder according to the general ~ ~ i39~
~/ I procedure of Rogers, U.S. 4,426,317. Gas phase ¦ copolymerizatioll was carried out in a small pilot plant Il similar in design to the laboratory gas phase reactor except ¦¦ that there was no separator in the gas recycle line. The t~
reactor had a reaction zone 30 cm in diameter, about 2 m tall. This run was conducted at 2.0 ~IPa and~ e}~ees C
I '~
average bed temperature with a recycle gas flow of about 1100 i kg/hr which gave a gas velocity ln the bed of about 30 cm/sec. The recycle gas stream consisted essentially of 84.4~ ethylene, 3.8% ~ydrogen, 9.3~ butene-l, and 2.5~
nitrogen. Catalyst was added with nitrogen to the fluidized ¦ bed at an average ra-te of 7.5 cc/hr, triethylaluminum ~TEA) ~'1 was added as a 10% solution in hexane at a rate of 4.9 cc/hr, !! and chloroform was added at a rate of 1.4 cc/hr. A film-grade ¦¦ polyrner having a melt index of 1.4, a density of 0.934, and a i¦ total ash content of 600 ppm was produced at an average rate P
¦¦ of about 7 kg/hr during 8 hours oE steady op~ration.
I¦ EXAMPL~ L
¦j ~t the conclusion of Example XXII, the hydrogen feed is discontinued while everything else is maintained ¦ essentially unchanged. Gradually, the hydrogen/ethylene li ratio drops, as determined by an on-line gas analyzer, as ¦~ recycle gases are lost from the reaction zone through purge Il to the instruments and by being removed with the polyethylene ¦¦ product, with no fresh hydrogen being added to the make-up gases. As the hydrogen level in the recycle gas decreases, il the polymer melt index drops until it is unmeasurably low.
j The polymerization rate, as determined by ethylene uptake and j by product removal from the reaction zone, is unchanged within experimental error. Thcre is no external evidence of reactor fouling. Hydrogen flow is then restarted, and the original hydrogen/ethylene ratio re-established. Within 18 hours, the melt index is again 1.4 and the polymer is again useful for fil~
r;,i 11 '3~3~;
The chloroform feed is then discontinued, all other ;
variables being held as constant as possible. Gradually, the CI~C13/V ratio decreases as the CIIC13 concentration in the recycle gas becomes lower due to loss of recycle gas from the system and the make-up gases being promoter-free. There is no significant change in the melt index of the polymer, but the polymerization rate drops and the ash content of the polymer increses to about 3000 ppm, too high for good quality film. The chloroform feed is then restarted at its original t feed rate. Polymerization rate picks up immediately, as judged from an increase in both bed temperature and polymer powder production, and reaches a level of about 10 kg/hr, after which the rate slowly declines and lines out at about 7 kg/hr. About 36 hours aEter chloroorm is readmitted to the reaction, ~he reactlorl àncl polym~r are restab:Lized at the~
original conditions and the polymer is again useEul for film.
Then the triethylaluminum feed is stopped, all other variables being held as constant as possible. The polymerization rate begins to decrease, slowly at first, and then rapidly. The ash content of the polymer increases correspondingly. When the polymerization rate reaches about 1 kg/hr, the reaction is terminated intentionally, and the reactor opened for inspection. There is no visible coating or fouling on the distribution plate or reactor walls.
This example illustrates ~n~trialkylaluminum, chloroform and hydrogQn, in the proper proportions, are essential to useful practice of this invention.
EXA~IPLE XXIII
The general procedure of Example XXII was repeated except that the catalyst had the formulation of the catalyst of Example XIII run 22 and propylene was the colnonomer.
Polymerization pressure was about 2.1 MPa, and average bed temperatures were in the range of 78 - 82 degrees C. The other run conditions and corresponding polymer properties obtained are given in Table XV. Each run in Table XV
1,1 ,1 -50-12~;.1'3')~
I represents a different condition of reasonably stable, ¦ operation during a 7-day period of continuous operation. At ¦ the end of the 7-day period, the reactor was shut down by ¦j failure of the polymer withdrawal system. There was no ¦¦ evidence of fouling of reactor walls or the distribution plate.
TABLE XV
Il _ I
ll Run # 38 39 40 41 42 l l . ~ l Recycle gas composition:
Ethylene 61.663.0 68.0 58.9 61.0 ! % Hydrogen 1.1 1.5 1.3 1.0 1.0 % Propylene 12.411.4 7.4 11.9 11.4 % Nitrogen 24.924.1 23.3 28.2 26.6 ¦ % Chloroform 0.007 0.00980.0073 0.012 0.015 I
Flow Rates:
¦ Catalys~ (cc/hr) 5.3 4.6 2.6 3.3 3.8 TE~ (cc/hr) 3.1 3.0 3.7 3.6 3.9 Production (kg/hr) 2.1 3.4 1.5 2.0 2.2 Polymer properties:
MI (dg/min) 1.1 0.87 0.76 0.90 0.48 l Density (g~cc) 0.916 0.917 0.920 0.919 0.915 ¦ Ash, ppm 390 367 340 347 ¦ V residue, ppm 1.6 0.9 1.1 1.1 1.1 _ EXAMPLE XXIV
Three samples of narrow molecular weight I ¦ distribution ethylene copolymers were made in a larger ¦ gas-phase fluidized-bed pilot plant polymerization system.
The reaction zone was 46 cm in diameter and about 3 m tall.
¦l It was topped by a disengaging zone of 92 cm diamerer. Gas ~¦ recycle piping led from the disengaging zone through a heat exchanger and recycle gas blower to the bottom of the reactor. A distribution plate at the bottom of the reactor ,I served to disperse or distribute the gas evenly at the bottom ¦¦ of the bed. Gas analyzers monitored the gas composition of !~ the recycle system and, via suitable instrumentation~
~¦ automatically adjusted flows of Eeed streams to keep th~ 'J~
Il I
~ `51-33~36 ~ 11 composition constant Catalyst was fed directly to the bed with an automatic catalyst feeder using nitrogen as the motive gas to convey the ca-talyst into the bed.
Triethylaluminum ~TEA) was pumped directly into the bed.
Polymer powder was automatically withdrawn to maintain a constant inventory of powder in the reactor. Eor all three samples, reaction pressure was about 3.5 MPa, average bed temperature ws about 92 degrees C, and the recycle gas rate was about 4525 kg/hr, which gave a gas velocity in the bed of crf~ .
abou-t 30 ~/sec. Average reaction conditions during the time each sample was collected and results for each sample are given in Table XVI.
Catalysts for these runs were made essentially as taught by Rogers in U.5. 4,~26,317. For runs 43 and 44, the cataLyst contpo5ition was 1.5 mmol tri-n-hcxylalum:irlulll, 0.1 rllmol n-octad~cyloxyvancldLurn oxydichloride and 1.0 mmol n-hexanol per gram of dry silica support. For run 45, the catalyst had the composition of 2.25 mmol tri-n-hexylaluminum, 0.2 mmol n-octadecyloxyvanadium oxydichloride and 1.0 mmol n-hexanol per gram of dry silica.
There was no evidence of reactor fouling after any of the runs.
, i3~396 ~ ~ ~ TABLE XVI
. ~ igl ~ _ .
¦ Run ~ 43 44 45 Recycle Gas Composition:
Nitrogen 5.6 5.9 6.8 I ~ Ethylene 86.185.1 84.8 i % ~ydrogen 4.4 5.1 5.3 , % Propylene 3.9 3.9 3.1 ¦ ~ Chloroform 0.0700.085 0.080 Other Poly~erization data:
Al/V ratio 42 29 26 ~/3/~eHe~- ratio 123 305 112 Production (kg/hr) 15 13 13 Polymer properties:
I MI (dg/min) 2.2 q.5 2.1 ~ Density (y/cc) 0.9530.954 0.9Sq I ~h,ppm 702 699 323 V residue, ppm 2.9 3.1 2.9 _ EXAMPLE XXV
A commercial gas-phase fluidized-bed polyme~rization ¦ is carried out in a polymerization system of the same general ¦ description as the pilot plant of example XXIV. `However, the reaction zone is 3.6 m in diameter and about 15 m tall.
Recycle gas rate is sufficient to give a gas velocity in the bed of about 30 cm/sec The polymerization is conducted at 3.5 MPa pressure and 93 degrees C average bed temperature with a feed stream targets of 6.0 ~ ~ nitrogen, 85.0 ethylene, 3.9 % propylene, 5.1 ~ hydrogen, and 0.07 ~
I chloroform. The catalyst has the formulation 1.4 mmol ¦¦ triethylaluminum, 0.1 mmol undecyloxyvanadium oxydichloride, ¦ 1.0 mmol n-octanol and is made in commerclal batches of 4S0 ~ kg each. The Al/V ratio during polymerization varies ¦~ slightly as monomer purity varies, but is in the range of 10 Il to 30.
¦¦ The polymer, producted at a rate of about 8.5 me-tric tons per hour, is an injection molding grade, has an _- !
3~3~3~
average melt inde~ of 5, an average density of Q.954, and an NVR of 1.9 plus or minus 0.1 This product is made in commercial runs of two weeks or longer without evidence of reactor fouling.
Similar results in the narrowing of the molecular weight distributions of ethylene polymers are obtained when the examples are repeated except that the catalyst components, component proportions, comonomers, comonomer proportions, and/or polymerizatlon conditions specified in the examples are replaced with catalyst components, component proportions, comonomers, comonomer proportions, and/or polymerization conditions -taught to be their equiva~ents in the specification.
While the present invention has been described herein with refcrellce to p~rticul~r emodiments thereof, a latitude o modiEication, various changes and substitutions are intencled in the foregoing disclosure, and it will be appreciated that in some instances some features of the invention will be employed without a corresponding use of other features without departing from the scope of the lnvention as set forth.
!l i ii ' -54-1!
Claims (49)
1. A process for polymerizing a monomer charge comprising ethylene comprising the steps of:
a) drying an inorganic oxide having surface hydroxyl groups to form a support that is substantially free of adsorbed water;
b) reacting the surface hydroxyl groups of the support with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the formula RxMR'yR''z, wherein M is a metal of Group III of the periodic table, R is an alkyl group containing 1 to 12 carbon atoms, R' and R'' are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z each can have a value of 0 to 2 and the sum of y and z is not greater than 3-x, to provide a treated support;
c) reacting the thus treated support with at least about 0.001 mol, per mol of organometallic compound, of at least one vanadium compound corresponding to a formula selected from (RO)n-VOX3-n and (RO)mVX4-m, in which formulas R represents a C1-C18 monovalent hydrocarbon radical that is free of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4;
d) reacting the product of step (c) with at least about 0.1 mol, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms; and e) contacting in a gas-phase reaction zone the catalyst product of step (d) with a monomer charge comprising ethylene to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution.
a) drying an inorganic oxide having surface hydroxyl groups to form a support that is substantially free of adsorbed water;
b) reacting the surface hydroxyl groups of the support with at least a substantially stoichiometric amount of at least one organometallic compound corresponding to the formula RxMR'yR''z, wherein M is a metal of Group III of the periodic table, R is an alkyl group containing 1 to 12 carbon atoms, R' and R'' are independently selected from the group consisting of H, Cl, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z each can have a value of 0 to 2 and the sum of y and z is not greater than 3-x, to provide a treated support;
c) reacting the thus treated support with at least about 0.001 mol, per mol of organometallic compound, of at least one vanadium compound corresponding to a formula selected from (RO)n-VOX3-n and (RO)mVX4-m, in which formulas R represents a C1-C18 monovalent hydrocarbon radical that is free of aliphatic unsaturation, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4;
d) reacting the product of step (c) with at least about 0.1 mol, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms; and e) contacting in a gas-phase reaction zone the catalyst product of step (d) with a monomer charge comprising ethylene to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution.
2. The process of Claim 1 wherein the support is an inorganic oxide selected from the group consisting of silica, alumina, magnesia, and mixtures thereof.
3. The process of Claim 1 wherein the organometallic compound is a compound corresponding to the formula RAlR'R'', wherein at least one of the R, R' and R'' substituents is an alkyl group containing 1 to 12 carbon atoms and the remaining substituents are independently selected from the group consisting of hydrogen and alkyl and alkoxy groups containing 1 to 12 carbon atoms.
4. The process of Claim 3 wherein the organometallic compound is a trialkylaluminum.
5. The process of Claim 4 wherein the trialkylaluminum is triethylaluminum.
6. The process of Claim 4 wherein the trialkylaluminum is tri-n-hexylaluminum.
7. The process of Claim 1 wherein the vanadium compound is a compound corresponding to the formula (RO)nVOCl3-n.
The process of Claim 7 wherein R is alkyl and n has a value of about 1.
9. The process of Claim 7 wherein n has a value of 0.
10. The process of Claim 1 wherein the vanadium compound is a compound corresponding to the formula (RO)mVC14-m.
11. The process of Claim 10 wherein m has a value of O.
12. The process of Claim 1 wherein the alcohol is a primary alcohol.
13. The process of Claim 12 wherein the alcohol is an alkanol containing at least 6 carbon atoms.
14. The process of Claim 1 wherein the amounts of materials employed in its preparation are such as to provide, as starting materials, about 5 to 30 mols of organometallic compound per mol of vanadium compound.
15. The process of Claim 1 wherein the amount of organometallic compound reacted with the surface hydroxyl groups of the support is the substantially stoichiometric amount.
. The process of Claim 1 wherein the inorganic oxide is dried at about 100° C. to 1000° C. until substantially all adsorbed water is removed and is then cooled to ambient temperature before being slurried.
17. The process of Claim 16 wherein the inorganic oxide is silica and the drying temperature is about 200° C. to 600° C.
18. The process of Claim 16 wherein the inorganic oxide is magnesia and the drying temperature is about 200° C. to 600° C.
19. The process of Claim 16 wherein the inorganic oxide is alumina and the drying temperature is about 500° C. to 600° C.
20. The process of Claim 1 wherein the organometallic and vanadium compounds are added to the reaction mixture in neat form.
21. The process of Claim 1 wherein at least one of the organometallic and vanadium compounds is added to the reaction mixture in the form of an inert liquid hydrocarbon solution.
22. A process of polymerizing a monomer charge comprising chloroform, ethylene and hydrogen comprising the steps of:
(a) drying an inorganic oxide selected from the group consisting of silica, alumina, magnesia, and mixtures thereof, having a surface hydroxyl groups to form a support that is substantially free of adsorbed water;
(b) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least one organometallic compound corresponding the formula RxAlR'yR''z wherein R is an alkyl group containing 1 to 12 carbon atoms, R' and R'' are independently selected from the group consisting of H, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z each can have a value of O to 2 and the sum of y and z is not greater than 3-x,to provide a treated support;
(c) reacting the thus-treated support with from between about 0.001 to about 3 mols, per mol of organometallic compound of at least one vanadium compound corresponding to a formula selected from at least one of the formulas (R'''O)n VOX3-n and (R'''O)m VX4-m in which formulas R''' is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 13 carbon atoms, X is Cl or Br, n has a value of O to 3, and m has a value of o to 4;
(d) reacting the product of step (c) with from about 0.1 mol to about 10 mols, per mol of organometallic compound, of an alcohol containing 1 to 13 carbon atoms; and (e) contacting in a gas-phase reaction zone, the catalyst product of step (d) with a monomer charge comprising chloroform, ethylene, and hydrogen to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution.
(a) drying an inorganic oxide selected from the group consisting of silica, alumina, magnesia, and mixtures thereof, having a surface hydroxyl groups to form a support that is substantially free of adsorbed water;
(b) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least one organometallic compound corresponding the formula RxAlR'yR''z wherein R is an alkyl group containing 1 to 12 carbon atoms, R' and R'' are independently selected from the group consisting of H, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z each can have a value of O to 2 and the sum of y and z is not greater than 3-x,to provide a treated support;
(c) reacting the thus-treated support with from between about 0.001 to about 3 mols, per mol of organometallic compound of at least one vanadium compound corresponding to a formula selected from at least one of the formulas (R'''O)n VOX3-n and (R'''O)m VX4-m in which formulas R''' is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 13 carbon atoms, X is Cl or Br, n has a value of O to 3, and m has a value of o to 4;
(d) reacting the product of step (c) with from about 0.1 mol to about 10 mols, per mol of organometallic compound, of an alcohol containing 1 to 13 carbon atoms; and (e) contacting in a gas-phase reaction zone, the catalyst product of step (d) with a monomer charge comprising chloroform, ethylene, and hydrogen to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution.
23. A process of polymerizing a monomer charge comprising chloroform, ethylene and hydrogen comprising the steps of:
(a) drying an inorganic oxide selected from the group consisting of silica, alumina, magnesia and mixtures thereof, having a surface hydroxyl groups to form a support that is substantially free of absorbed water;
(b) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least one organometallic compound corresponding to the formular RXAlR'yR''z wherein R is an alkyl group containing 1 to 12 carbon atoms, R' and R'' are independently selected from -the group consisting of H, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z each can have a value of 0 to 2 and the sum of y and z is not greater than 3-x, to provide a treated support;
(c) reacting the thus-treated support with from between about 0.001 mol to about 3 mols, per mol of organometallic compound, of at least one vanadium compound corresponding to a formula selected from at least one of the formulas (R'''O)n VOX3-n and (R'''O)m VX4-m in which formulas R''' is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 18 carbon atoms, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4;
(d) reacting the product of step (c) with from about 0.1 mol to about 10 mols, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms; and (e) contacting in a gas-phase reaction zone, without washing the catalyst product of step (d), the catalyst product with said monomer charge comprising chloroform, ethylene, and hydrogen to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution.
(a) drying an inorganic oxide selected from the group consisting of silica, alumina, magnesia and mixtures thereof, having a surface hydroxyl groups to form a support that is substantially free of absorbed water;
(b) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least one organometallic compound corresponding to the formular RXAlR'yR''z wherein R is an alkyl group containing 1 to 12 carbon atoms, R' and R'' are independently selected from -the group consisting of H, and alkyl and alkoxy groups containing 1 to 12 carbon atoms, x has a value of 1 to 3, and y and z each can have a value of 0 to 2 and the sum of y and z is not greater than 3-x, to provide a treated support;
(c) reacting the thus-treated support with from between about 0.001 mol to about 3 mols, per mol of organometallic compound, of at least one vanadium compound corresponding to a formula selected from at least one of the formulas (R'''O)n VOX3-n and (R'''O)m VX4-m in which formulas R''' is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 18 carbon atoms, X is Cl or Br, n has a value of 0 to 3, and m has a value of 0 to 4;
(d) reacting the product of step (c) with from about 0.1 mol to about 10 mols, per mol of organometallic compound, of an alcohol containing 1 to 18 carbon atoms; and (e) contacting in a gas-phase reaction zone, without washing the catalyst product of step (d), the catalyst product with said monomer charge comprising chloroform, ethylene, and hydrogen to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution.
24. A process of polymerizing a monomer charge comprising chloroform, ethylene and hydrogen comprising the steps of:
(a) drying at between 100°C to 1000°C a silica support having surface hydroxyl groups to form a support that is substantially free of adsorbed water;
(b) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of triethylaluminum per gram of silica support, to provide a treated support;
(c) reacting the thus-treated support with from about 0.001 mol to about 3 mols, per mol of triethylaluminum compound, of VC14;
(d) reacting the product of step (b) with from about 0.1 mol to about 10 mols, per mol of triethylaluminum, of n-hexanol;
(e) contacting in a gas-phase reaction zone, without washing the catalyst product of step (d), the catalyst product with a monomer charge comprising chloroform, ethylene, and hydrogen to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution without fouling the gas-phase reaction zone.
(a) drying at between 100°C to 1000°C a silica support having surface hydroxyl groups to form a support that is substantially free of adsorbed water;
(b) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of triethylaluminum per gram of silica support, to provide a treated support;
(c) reacting the thus-treated support with from about 0.001 mol to about 3 mols, per mol of triethylaluminum compound, of VC14;
(d) reacting the product of step (b) with from about 0.1 mol to about 10 mols, per mol of triethylaluminum, of n-hexanol;
(e) contacting in a gas-phase reaction zone, without washing the catalyst product of step (d), the catalyst product with a monomer charge comprising chloroform, ethylene, and hydrogen to produce a high yield polymerized monomer having a narrow-to-intermediate molecular weight distribution without fouling the gas-phase reaction zone.
. . The process of Claim 22 wherein said inorganic oxide is dried at from about 100° C. to 1000° C. until substantially all adsorbed water is removed.
26. The process of Claim 25 wherein the inorganic oxide is alumina, and said drying temperature for said alumina is from about 400° C. to about 600° C. in order to narrow the molecular weight distribution of said polymerized monomer.
27. The process of Claim 22 wherein said monomer charge additionally comprises at least one alpha olefin containing 3 to 8 carbon atoms.
28. The process of Claim 22 wherein the organometallic compound is a trialkylaluminum.
29. The process of Claim 28 wherein the trialkylaluminum is triethylaluminum.
30. The process of Claim 28 wherein trialkylaluminum is tri-n-hexylaluminum.
31. The process of Claim 22 wherein the vanadium compound is a compound corresponding to the formula (R'''O)nVOC13-n.
. The process of Claim 31 wherein n has a value of 0.
33. The process of Claim 22 wherein the vanadium compound is a compound corresponding to the formula (R'''O)mVCl4-m.
34. The process of Claim 33 wherein m has a value of 0.
35. The process of Claim 22 wherein the alcohol is a primary alcohol.
36. The process of Claim 35 wherein the alcohol is an alkanol containing at least 6 carbon atoms.
37. The process of Claim 22 wherein the amounts of materials employed are such as to provide, as starting materials, about 5 to 30 mols of organometallic compound per mol of vanadium compound.
38. The process of Claim 31 wherein R''' is alkyl and n has a value of about 1.
39. The process of Claim 22 wherein the amount of organometallic compound reacted with the surface hydroxyl groups of the support is the substantially stoichiometric amount.
40. A process of polymerizing a monomer charge comprising chloroform, ethylene, and hydrogen in a gas-phase, fluidized-bed, reaction zone which comprises a bed of particulate substantially polymerized ethylene particles and is under operating conditions for polymerizing ethylene using the monomer charge, said process comprising the steps of:
a) drying at from about 100° to about 1000°C. an in-organic oxide selected from the group consisting of silica, alumina, magnesia, and mixtures thereof, having surface hydroxyl groups to form a support that is substantially free of adsorbed water;
b) cooling the dried inorganic oxide of step (a) to ambient temperature;
c) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least one organometallic compound corres-ponding to the formula RAlR'R'' wherein at least one of the R, R', and R'' substitutents is an alkyl group containing 1 to 12 carbon atoms and the remaining substituents are independently selected from the group consisting of hydrogen and alkyl and alkoxy groups containing 1 to 12 carbon atoms, to provide a treated support;
d) reacting the thus-treated support with from about 0.001 mol to about 3 mols, per mol of RAl'R'' compound, of at least one vanadium compound correspond-ing to a formula selected from at least one of the formulas (R'''O)nVOC13-n and (R'''O)mVC14-m in which formula R'''is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 18 carbon atoms, n has a value of 0 to 3, and m has a value of 0 to 4;
e) reacting the product of step (d) with at least about 0.1 mol to about 10 mols, per mol of RAlR'R'' compound, of an alcohol containing 1 to 18 carbon atoms;
f) drying the product of step (e);
g) feeding the product of step (f) into a gas-phase reaction zone in order to form part of the bed in the fluidized-bed reaction zone;
h) feeding, separately and independently of said feeding step (g), into the gas-phase reaction zone a triethylaluminum such that such bed in the gas-phase reaction zone comprises the product of step (e), triethylaluminum, and particulate substantially polymerized ethylene particles;
i) fluidizing the bed of step (h) at a temperature of from about 50°C to about 120°C by introducing into the reaction zone a gas mixture comprising ethylene, hydrogen, and chloroform;
j) removing particulate substantially polymerized ethylene particles from the reaction zone having a narrow-to-intermediate molecular weight distribution;
and:
k) recycling unreacted gas mixture of step (i) from the top of the reaction zone, through a heat exchanger means, and into the bottom of the reaction zone.
a) drying at from about 100° to about 1000°C. an in-organic oxide selected from the group consisting of silica, alumina, magnesia, and mixtures thereof, having surface hydroxyl groups to form a support that is substantially free of adsorbed water;
b) cooling the dried inorganic oxide of step (a) to ambient temperature;
c) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least one organometallic compound corres-ponding to the formula RAlR'R'' wherein at least one of the R, R', and R'' substitutents is an alkyl group containing 1 to 12 carbon atoms and the remaining substituents are independently selected from the group consisting of hydrogen and alkyl and alkoxy groups containing 1 to 12 carbon atoms, to provide a treated support;
d) reacting the thus-treated support with from about 0.001 mol to about 3 mols, per mol of RAl'R'' compound, of at least one vanadium compound correspond-ing to a formula selected from at least one of the formulas (R'''O)nVOC13-n and (R'''O)mVC14-m in which formula R'''is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 18 carbon atoms, n has a value of 0 to 3, and m has a value of 0 to 4;
e) reacting the product of step (d) with at least about 0.1 mol to about 10 mols, per mol of RAlR'R'' compound, of an alcohol containing 1 to 18 carbon atoms;
f) drying the product of step (e);
g) feeding the product of step (f) into a gas-phase reaction zone in order to form part of the bed in the fluidized-bed reaction zone;
h) feeding, separately and independently of said feeding step (g), into the gas-phase reaction zone a triethylaluminum such that such bed in the gas-phase reaction zone comprises the product of step (e), triethylaluminum, and particulate substantially polymerized ethylene particles;
i) fluidizing the bed of step (h) at a temperature of from about 50°C to about 120°C by introducing into the reaction zone a gas mixture comprising ethylene, hydrogen, and chloroform;
j) removing particulate substantially polymerized ethylene particles from the reaction zone having a narrow-to-intermediate molecular weight distribution;
and:
k) recycling unreacted gas mixture of step (i) from the top of the reaction zone, through a heat exchanger means, and into the bottom of the reaction zone.
41. A process of polymerizing a monomer charge comprising an alpha olefin, chloroform, ethylene, and hydrogen in a gas-phase, fluidized-bed, reaction zone which comprises a bed of particulate substantially polymerized ethylene particles and is under operating conditions for polymerizing ethylene using the monomer charge, said process comprising the steps of:
a) drying at from about 100° to about 1000° C an inorganic oxide selected from the group consisting of silica, alumina, magnesia, and mixture thereof, having surface hydroxyl groups to form a support tht is substantially free of adsorbed water;
b) cooling the dried inorganic oxide of step (a) to ambient temperature;
c) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least organometallic compound corresponding to the formula RAlR'R'' wherein at least one of the R, R', and R'' substituents is an alkyl group containing 1 to 12 carbon atoms and the remaining substituents are independently selected from the group consisting of hydrogen and alkyl and alkoxy groups containing 1 to 12 carbon atoms, to provide a treated support;
d) reacting the thus-treated support with from about 0.001 mol to about 3 mols, per mol of RAlR'R'' compound, of at least one vanadium compound corresponding to a formula selected from at least one of the formulas (R'''O)nVOC13-n and (R'''O)mVC14-m in which formula R''' is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 18 carbon atoms, n has a value of O to 3, and m has a value of O to 4;
e) reacting the product of step (d) with at least about 0 1 mol to about 10 mols, per mol of RAlR'R'' compound, of an alcohol containing 1 to 18 carbon atoms;
f) drying the product of step (e);
g) feeding the product of step (f) into a gas-phase reaction zone in order to form part of the bed in the fluidized-bed reaction zone;
h) feeding, separately and independently of said feeding step (g), into the gas-phase reaction zone a triethylaluminum such that such bed in the gas-phase reaction zone comprises the product of step (e), the triethylaluminum, and particulate substantially polymerized ethylene particles;
i) fluidizing the bed of step (h) at a temperature of from about 50°C to about 120°C by introducing into the reaction zone a gas mixture-comprising an alpha olefin, ethylene, hydrogen, and chloroform;
j) removing particulate substantially polymerized ethylene particles from the reaction zone having a narrow-to-intermediate molecular weight distribution;
and k) recycling unreacted gas mixture of step (i) from the top of the reaction zone, through a heat exchanger means, and into the bottom of the reaction zone.
a) drying at from about 100° to about 1000° C an inorganic oxide selected from the group consisting of silica, alumina, magnesia, and mixture thereof, having surface hydroxyl groups to form a support tht is substantially free of adsorbed water;
b) cooling the dried inorganic oxide of step (a) to ambient temperature;
c) reacting the surface hydroxyl groups of the support with a substantially stoichiometric amount of at least organometallic compound corresponding to the formula RAlR'R'' wherein at least one of the R, R', and R'' substituents is an alkyl group containing 1 to 12 carbon atoms and the remaining substituents are independently selected from the group consisting of hydrogen and alkyl and alkoxy groups containing 1 to 12 carbon atoms, to provide a treated support;
d) reacting the thus-treated support with from about 0.001 mol to about 3 mols, per mol of RAlR'R'' compound, of at least one vanadium compound corresponding to a formula selected from at least one of the formulas (R'''O)nVOC13-n and (R'''O)mVC14-m in which formula R''' is a monovalent hydrocarbon radical that is free of aliphatic unsaturation having from 1 to 18 carbon atoms, n has a value of O to 3, and m has a value of O to 4;
e) reacting the product of step (d) with at least about 0 1 mol to about 10 mols, per mol of RAlR'R'' compound, of an alcohol containing 1 to 18 carbon atoms;
f) drying the product of step (e);
g) feeding the product of step (f) into a gas-phase reaction zone in order to form part of the bed in the fluidized-bed reaction zone;
h) feeding, separately and independently of said feeding step (g), into the gas-phase reaction zone a triethylaluminum such that such bed in the gas-phase reaction zone comprises the product of step (e), the triethylaluminum, and particulate substantially polymerized ethylene particles;
i) fluidizing the bed of step (h) at a temperature of from about 50°C to about 120°C by introducing into the reaction zone a gas mixture-comprising an alpha olefin, ethylene, hydrogen, and chloroform;
j) removing particulate substantially polymerized ethylene particles from the reaction zone having a narrow-to-intermediate molecular weight distribution;
and k) recycling unreacted gas mixture of step (i) from the top of the reaction zone, through a heat exchanger means, and into the bottom of the reaction zone.
42. The process of Claim 22 additionally comprising removing particulate substantially polymerized monomer particles from the reaction zone having a narrow-to-intermediate molecular weight distribution.
43. The process of Claim 23 additionally comprising removing particulate substantially polymerized monomer particles from the reaction zone having a narrow-to-intermediate molecular weight distribution.
44. The process of Claim 24 additionally comprising removing particulate substantially polymerized monomer particles from the reaction zone having a narrow-to-intermediate molecular weight distribution.
45 . The process of Claim 22 wherein said contacting in a gas-phase reaction zone is without having washed the catalyst product.
46. The process of Claim 42 additionally comprising recycling unreacted monomer charge from the top of the reaction zone to the bottom of the reaction zone.
47. The process of Claim 43 additionally comprising recycling unreacted monomer charge from the top of the reaction zone to the bottom of the reaction zone.
48. The process of Claim 44 additionally comprising recycling unreacted monomer charge from the top of the reaction zone to the bottom of the reaction zone.
49. The process of Claim 45 additionally comprising recycling unreacted monomer charge from the top of the reaction zone to the bottom of the reaction zone.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/715,271 US4665140A (en) | 1982-11-24 | 1985-03-25 | Process for polymerizing a monomer charge |
| US715,271 | 1991-06-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1263996A true CA1263996A (en) | 1989-12-19 |
Family
ID=24873339
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000504612A Expired CA1263996A (en) | 1985-03-25 | 1986-03-20 | Process for polymerizing a monomer charge |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS61275306A (en) |
| AU (1) | AU600894B2 (en) |
| CA (1) | CA1263996A (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4435518A (en) * | 1982-11-24 | 1984-03-06 | Cities Service Co. | Polymerization catalyst |
-
1986
- 1986-03-20 CA CA000504612A patent/CA1263996A/en not_active Expired
- 1986-03-20 AU AU54938/86A patent/AU600894B2/en not_active Ceased
- 1986-03-25 JP JP6500986A patent/JPS61275306A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| AU5493886A (en) | 1986-10-02 |
| JPS61275306A (en) | 1986-12-05 |
| AU600894B2 (en) | 1990-08-30 |
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