GB1597898A - Catalyst compositions for use in alpha-olefine polymerisation - Google Patents

Description

(54) CATALYST COMPOSITIONS FOR USE IN ALPHA-OLEFINE POLYMERISATION (71) We, EXXON RESEARCH AND ENGINEERING COMPANY, a Corporation duly organised and existing under the laws of the State of Delaware, United States of America, of Linden, New Jersey, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- It is well known in the art (U.S. 3,953,414, Belg. 846,314, Ger. DT 262W886, Brit 1,335,887, Ger. DT 263585, Brit 1,140,659, Ger. DT 2612--650, South Africa 7,503,470, Ger. DT 2355-886, Jap. 5106W586, South Africa 7507-382, Ger. DT 2638429, Jap. 51057-789, U.S. 3,992,322, Jap. 52027-090, and U.S.

3,400,110), to use an alkyl metal compound of Groups 1-flI in combination with a transition metal compound of Groups IVA--VIII as a catalyst system for olefinic polymerization. Our copending Applications 2351/78 and 2353/78 (Serial Nos.

1,595,252 and 1,593,934) are also concerned. with catalyst systems using such transition metal compounds all of the alkyl metal compounds are effective for the polymerization of ethylene, only a few are effective for the preparation of isotactic polymers of propylene and higher alpha-olefins and only Et2AlCl, AlEt3 and i Bu2AIH have any important commercial utility.

A major cost involved in the polymerization of the alpha-olefins is the cost of the catalyst components. Therefore, the cost of the manufacture of the polymer can be effectively reduced by the use of catalyst systems having a high polymerization activity. A further concern is the ability to produce polymers having a minimum amount of catalyst residues thereby eliminating a costly deashing operation. A still further concern is the ability to produce polymers having a high degree of isotactic stereoregularity thereby enabling the manufacturer to eliminate or reduce the costly operation involving the removal and separation of atactic polymer from the isotactic polymer. The improved catalyst system of the present invention provides a means for the manufacturer to obtain these desirable realizations.

The catalyst compositions of the present invention which can be employed in alpha-olefin polymerizations comprise a Group IVA--VIII transition metal halide, one or more Lewis bases, and at least one organo metal compound of the formula RnMR'3 where n=l to 3, M is Al, Ga or In, and R' is a C1-C20 primary group, said group being alkyl alkenyl or aralkyl and R is a C3 to C20 secondary or tertiary group, said group being alkyl, cycloalkyl, alkenyl or aralkyl. The periodic table whic applies in the specification is that appearing in Notes on the use of the classification Key of Abridgments of Patent Specifications'.

The halogen atom in the Group IVA--VIII transition metal halide is preferably chlorine or bromine and the transition metal halide may be in the form of solid crystalline compounds, solid solutions or compositions with other metal salts. It is supported on a crystalline chloride layer lattice compound. By chloride layer lattice compounds we mean those compounds having layer structures in which the anion layers are predominantly chlorides. For highest stereospecificity it is desirable to have the transition metal halide, or its support composition, in the layer lattice structure with very small crystallites, high surface area, or sufficient defects or foreign components to facilitate high dispersion during polymerization.

The transition metal halide may also contain various additives such as Lewis bases, pi bases, polymers or organic or inorganic modifiers. Vanadium and titanium halides such as VCl3, VBr3, TiC13, TiC14, TiBr3 or TiBr4 are preferred, most preferably TiCI3 or TiCI4 and mixtures thereof. The most preferred TICS3 compounds are those which contain TiCI4 edge sites on a layer lattice support such as alpha, delta, or gamma TiC13 or various structures and modifications of TiCI3, MgCI2 or other inorganic compounds having similar layer lattice structures. The most preferred TiCl4 compounds are those supported on chloride layer lattice compounds such as MgCl2. Other anions may be also present instead of chloride ions. such as other halides, pseudo-halides, alkoxides, hydroxides, oxides or carboxylates, providing that sufficient chloride is available for isospecific site formation. Mixed salts or double salts such as K2TiCI6 or MgTiCl6 can be employed alone or in combination with electron donor compounds. Other supports besides MgCI2 which are useful are hydroxychlorides. The most preferred transition metal haideisTiCl4 containing MgCl2 especially in the presence of Lewis bases (electron donor compounds).

The Lewis bases are employed in combination with the organo metal compound and with the Group IVA--VIII transition metal halide as long as they do not cause excessive cleavage of metal-carbon bonds or loss of active sites. A wide varity of Lewis bases may be used including such types as amines (primary and secondary), esters, phosphines, phosphine oxides, phosphates (alkyl, aryl), phosphites, hexaalkyl phosphoric triamides, dimethyl sulfoxide, dimethyl formamide, ethers, epoxides, ketones, saturated and unsaturated heterocycles, or cyclic ethers and mixtures thereof. Typical examples are diethyl ether, dibutyl ether, tetrahydrofuran, ethyl acetate, methyl p-toluate, ethyl p-anisate, ethyl benzoate, phenyl acetate, amyl acetate, methyl octanoate, acetophenone, benzophenone, triethyl amine, tributylamine, dimethyl decylamine, pyridine, Nmethylpiperidine and 2,2,6,6 tetramethylpiperidine. The most preferred are esters of carboxylic acids such as ethylbenzoate.

Salts of Group IA--IIIB metals may also be employed with the catalysts if they are partially or wholly solubilized by reaction with the organo metal components.

Particularly useful are the carboxylates, alkoxides and aryloxides of magnesium and aluminum. Examples include Mg(OOCRfl)2, R"O Mg OOCR", ClMgOR", Mg(OR )2, RwAIOOCCeH5, RtAI(OOCR)2 and R't2AIOR", where R" is a hydrocarbyl group. Most preferred are the carboxylate salts of magnesium and aluminum prepared in situ by reacting the organometal compounds with carboxylic acids in hydrocarbon solvents.

Regarding the cocatalysts of the general formula RnMR'3~n n is preferably I- 2, and most preferably n is 2. Also it is preferred that R' is C2-C10 primary alkyl or aralkyl and most preferably C2-C4 primary alkyl. The R group is preferably a C4- C16 secondary or tertiary alkyl group or cycloalkyl group and is most preferably one which is not readily susceptible to elimination or displacement by monomer during polymerization. In addition to the simple secondary alkyl groups, other groups are also effective in which M, e.g. aluminium, is attached to a secondary or tertiary carbon atoms, i.e., cyclohexyl, cyclooctyl, tert-butyl, tert-amyl and s-norbornyl.

The most preferred compositions have the formula RnAIR'3~n in which the secondary and tertiary alkyl groups contain 410 carbons and n=2. Mixtures of these cocatalysts with conventional alkyl metal cocatalysts also yields improved results.

Suitable non-limiting examples include i-Pr2AlEt, s-BuAlEt2, s-Bu2AlEt, t BuAlEt2, t-Bu2AlEt, s-Bu3Al, l,l-dimethylheptyl AlEt2, s-Bu2Aln-C1BH33, t Bu2AlCH2C6H5, s-Bu(t-Bu)Aln-Bu, cyclohexyl2AlEt, s-pentyl Ali-Bu2, t-Bu2AlMe, t-Bu2Aln-C8H,7, (2-ethylcyclopentyl)2AlEt, 2-(3-ethylnorbornyl)AlEt2, 2-norbornyl Ali-Bu2, (2-norbornyl)2Ali-Bu, acenaphthyl Ali-Bu2 (ethylene naphthyl Al-iBu2), 3ethyl-5-ethylidinenorbornyl AlE, 9-i-bu-9-alumino-3,3,l-bicyclononane, t Bu2InEt and s-Bu2GaEt.

Preferred compounds include those in the above list which have the formula R1~2AIR'2~1. The most preferred compounds in the above list have the formula R2AIR'.

One method of preparing these secondary alkyl aluminum compounds is to react internal olefins with AliBu3 or i-Bu2AIH to add Al-H across the double bond to form sec-strained ring compound, AIR3 may be used to add Al-R across the double bond and obtain preferred compounds which are very resistant to displacement or elimination. Strained ring olefins include cyclopentene, norbornene, norbornadiene, ethylidene norbornene and dicyclopentadiene. This method is preferred because of raw material availability and simplicity of reaction, although this invention is not limited by the method of synthesis.

Other methods include the direct synthesis from the reactive metals and the secondary or tertiary halides, the various organometallic syntheses involving ligand exchange between Al, Ga or In compounds and secondary or teritary alkyl metal compounds of more electropositive metals such as Group IA and IIA, and the reaction of the metals with the alkyl mercury compounds. Particularly useful is the general reaction of secondary or tertiary alkyl lithium compounds with R'MX2 or R' > MX because it takes place readily in dilute hydrocarbon solutions.

Although di-secondary alkyl aluminum compounds are preferred to monosecondary alkyl compounds, the mono-alkyl types become more effective the greater the steric bulk of the group as long as it does not interfere with active site formation or lead to decomposition under reaction conditions.

The preferred concentration of the transition metal in the polymerization zone is 0.001 to 5mM, more preferably less than 0.1 mM. The molar ratio of the organo metal compound to the transition metal halide is preferably 0.5:1 to 50:1, more preferably 1:1 to 20:1, most preferably 5:1. The molar ratio of Lewis base to organometal compound can vary widely, but is preferably 0.1:1 to 1:1.

The catalyst system of the invention enables the process for making alpha olefin polymers having a high degree of isotactic stereoregularity to be carried out at a temperature of 25 to i500C., more preferably 400 to 800C., at pressures of 1 atm. to 50 atm. The reaction time for polymerization is 0.1 to 10 hours, more preferably 0.5 to 3 hours. Due to the high catalyst activity, shorter times and temperatures below 800 C. can be readily employed.

The reaction solvent for the system can be any inert paraffinic, naphthenic or aromatic hydrocarbon such as benzene, toluene, xylene, propane, butane, pentane, hexane, heptane, cyclohexane, and mixtures thereof. Preferably, excess liquid monomer is used as solvent. Gas phase polymerizations may also be carried out with or without minor amounts of solvent.

Typical examples of C2-C20 alpha-olefinic monomers employed in the present invention for the manufacture of homo- co- and terpolymers are ethylene, propylene, butene-l, pentene-l, hexene-l, octadecene- 1, 3-methylbutene- 1, styrene, ethylidene norbornene and 1,5-hexadiene and mixtures thereof. Isotactic polymerization of propylene and higher olefins is especially preferred, including block copolymerizations with ethylene.

The trialkyl metal compound and the supported transition metal compound can be added separately to the reactor or premixed before addition to the reactor, but are preferably added separately. Replacing the secondary or tertiary alkyl groups by bulky or hindered alkoxy, phenoxy or dialkylamide groups does not provide the improved catalyst activity achieved by the cocatalyst in this invention.

Alternative embodiments of the invention with respect to the cocatalysts (RnMR'3~n) is to use directly the reaction products of 3R2Mg+2MX3 < 2R3M+3MgX2; R2Mg+R'MX2 < R2MR'+MgX2; qr RMgX'+R'2MXeRMR'2+MgXX'.

In the case of the formation of R2MR' and R3M, the metal di- or trihalide compounds which are used are R'MX2, MX3 or a mixture thereof, wherein M is Al, Ga or In, R' is C1 to C30 primary alkyl, alkenyl, or aralkyl groups or hydrogen; X is chloride, bromide or a monovalent anion which cannot initiate polymerization of olefinic monomers, wherein the anion is alkoxide, phenoxide, thioalkoxide, carboxylate or a mixture thereof. Typical examples are ethyl aluminum dichloride, aluminum trichloride, ethyl aluminum dibromide, ethyl chloroaluminum bromide, octyl aluminum dichloride, ethyl indium dichloride, butyl aluminum dichloride, benzyl aluminum dichloride, ethyl chloroaluminum butoxide, and mixtures thereof. Mixtures of metal halide compounds can be readily employed.

The C2-C4 alkyl aluminum dihalides are most preferred for high stereospecificity and the monoalkylaluminum dichlorides are most preferred.

The diorganomagnesium compound has the general formula R3Mg wherein R can be the same as or different and is a C3 to C20 secondary or tertiary alkyl, cycloalkyl, aralkyl or alkenyl group. Typical, but non-limiting examples are (s Bu)2Mg, (t-Bu)2Mg or (iPr)2Mg. Mixtures of diorganomagnesium compounds can be readily employed providing at least one secondary or tertiary group is present.

The most preferred organic groups are secondary and tertiary alkyl groups, e.g. t Bu or s-Bu.

The molar ratio of the alkyl metal halide compound (R'MX2) to the diorganomagnesium compound is preferably 0.5:1 to 2:1, more preferably 0.7:1, and most preferably 1:1. For the MX3 compound the ratio is preferably 1:1 to 1:3, most preferably 2:3. The number of moles of Lewis base can vary widely but is preferably equal to or less than the sum of the moles of the metal halide compound the diorganomagnesium compound. The molar ratio of the metal halide compound or the diorganomagnesium compound to the transition metal compound is preferably less than about 50:1 and more preferably less than 20:1.

The metal halide compound and diorganomagnesium compound can be added separately to the reactor containing the transition metal compound but are preferably premixed before addition to the reactor. Employing either the metal halide compound or the diorganomagnesium compound alone with the transition metal compound does not provide the improved catalyst efficiency and stereospecificity as envisaged m this thisaplication. In order to attain this, it is necessary to employ both the metal halide compound and diorganomagnesium compound in combination with the transition metal compound in the critical proportions as previously defined. The concentration of the transition metal in the polymerization zone is preferably 0.001 to 5 mM, more preferably less than 0.1 mM.

In the case of the formation of RMR2,, the metal alkyl compounds which are used are R'2MX, R'3M or a mixture thereof, wherein M is Al, Ga or In, R' is Cl to C primary alkyl, alkenyl, aralkyl groups or hydrogen; X is a monovalent anion which cannot initiate polymerization of olefins, such as F, Cl, Br, OR", SR" or OOCRN, wherein Rt is a C1 to C20 alkyl, branched alkyl, cycloalkyl, aryl, naphthenic, aralkyl or alkenyl group, X is more preferably Cl or Br and most preferably Cl. Typical examples are dimethyl aluminum chloride, aluminum triethyl, diethylaluminum bromide, diethylaluminum iodide, diethylaluminum benzoate, diisobutylaluminum hydride, dioctylaluminum chloride, diethylgallium butoxide, diethylindium neodecanoate, triethylindium, dibenzylaluminum chloride and mixtures thereof. Mixtures of metal alkyl compounds can be readily employed. The C24 alkyl aluminum compounds are preferred for high stereospecificity, and the dialkyl aluminum chlorides are most preferred.

The mono-organomagnesium compound has the general formula RMgX wherein R is a C3 to C20 secondary or tertiary alkyl, cycloalkyl, aralkyl or alkenyl roups. X is an anion which cannot initiate polymerization of olefins, such as Cl, r, OR", SR" and 00CUR', wherein R" is a C, to C20 alkyl, branched alkyl, cycloalkyl naphthenic, aryl, aralkyl, allyl or alkenyl group. Typical examples are s BuMgC1, t-BuMgC1, s-BuMgOOCCeH5, or s-BuMgOC15H31 and mixtures thereof.

Mixtures of organomagnesium compounds can be readily employed. The most preferred X groups are OR" and OOCR" and the most preferred R groups are secondary or tertiary alkyls.

The molar ratio of the organomagnesium RMgX compound to the metal alkyl compound (R'2MX or R'3M) is preferably 2:1 to 1:2, most preferably 1:1. The number of moles of Lewis base can vary widely but is preferably equal to or less than the sum of the moles of the metal alkyl compound and the organomagnesium compound. The molar ratio of the metal alkyl compound or the organomagnesium compound to the transition metal compound is preferably less than 20:1 and more preferably less than 10:1.

The metal alkyl compound (R'2MX or R'3M) and organomagnesium compound RMgX can be added separately to the reactor containing the transition metal compound but are preferably premixed before addition to the reactor.

Employing either the metal alkyl compound or the organomagnesium compound alone with the transition metal compound does not provide the improved catalyst efficiency and stereo-specificity as envisaged in this application. In order to attain this it is necessary to employ both the metal alkyl compound and organomagnesium compound in combination with the transition metal compound in the proportions previously defined.

EXAMPLE 1 An aluminum alkyl compound containing both sec-butyl and ethyl groups was prepared by mixing equimolar amounts of (sec-butyl)2Mg 16 Et2O and ethyl aluminum dichloride in heptane, heating to 650C., 15 min., separating the magnesium chloride solids and vacuum stripping the clear solution. NMR analysis indicated the composition sBu2AlEt 0.45Et2O. Metals analysis showed that only 0.50% Mg was present in this fraction.

The above nquld alkyl aluminum compound (0.2 g) was used as cocatalyst with 0.2 g catalyst prepared by reacting anhydrous MgCl2 (5 moles) with Tics4. CeHsCOOEt (1 mole) in a ball mill 4 days, followed by a neat TiCl4 treatment at 80"C., 2 hours, washed with heptane and vacuum dried. The catalyst contained 2.68% Ti. Propylene was polymerized in 500 ml n-heptane at 650C., 1 hour at 765 770 mm. Polymerization rate was 130 g/g catalyst/hour and the polymer insoluble in boiling heptane=97.6%.

EXAMPLE 2 Three alkyl aluminum compounds containing sec-butyl groups were prepared by reacting the proper stoichiometric amounts of sec-butyllithium in heptane with either ethyl aluminum dichloride or diethyl aluminum chloride, heating to boiling, filtering the insoluble LiCI, and vacuum stripping the clear solutions. Nearly theoretical yields were obtained of s-BuEtA1C1 (A), s-Bu2EtAl (B) and s-BuEt2Al (C). Compositions were established by rH and 13C NMR and by G.C. analysis of the alkyl fragments.

Polymerizatlons were carried out as in Example 1 using I mmole aluminum alkyl compound and 0.2 g of the supported TiCl4 catalyst. The results summarized in Table I are compared to those obtained using the control ethyl aluminum compounds. In all runs with sec-butyl alkyls, both activity and stereo-specificity (heptane insoluble) were higher than those obtained with the conventional ethyl aluminum compounds. The trialkyl were far superior to the dialkyl aluminum chlorides and the di-sec-butyl aluminum ethyl was clearly superior to the mono sec-butyl aluminum di-ethyl compound.

TABLE I Rate Run Al Alkyl g/g Cat/hour % HI A Et2AICI control 48.9 68.0 B s-Bu, 07EtAIClo,93 64.6 79.1 Et3Al control 344 83.1 D s-BuEt2Al 380 90.3 E s-Bu3EtAl 357 93.0 Run B is outside the scope of the invention but is included for comparison purposes.

EXAMPLE 3 Sec-pentyl aluminum diisobutyl was prepared by reacting 19.57 g i-Bu2AlH with 75 ml pentene-2 in a glass lined 300 cc bomb at 135-1400C. for 16 hours, then 1500C. for 7 hours. The solution was vacuum stripped at 250C., yielding 28.1 g of the neat sec-pentyl aluminum compound.

Propylene was polymerized as in Example 2 using 0.212 g (1 mmole) sec-pentyl aluminum diisobutyl as the cocatalyst. Polymerization rate was 383 g/g Cat/hr and % HI=92.7. Comparison with AlEt3 control (Ex. 2, Run C) shows that the sec pentyl aluminum compound gave substantial improvement, particularly in stereospecificity.

EXAMPLE 4 The alkyl metal cocatalysts used in the compositions of the invention are particularly advantageous in having a much smaller effect of concentration (or alkyl metaVTi) on stereo-specificity, thereby simplifying plant operation and permitting better control of product quality. The results are summarized in Table II for di-sec-butyl aluminum ethyl in contrast to AlEt3 using the propylene polymerization procedure of Example 2.

TABLE II Run Al Alkvl Conc., mM Rate % HI F s-Bu2AlEt 2 357 93.0 G s-Bu2AlEt 4 484 83.4 H AlEt3 Control 2 344 83.1 I AlEt3 Control 4 290 64.9 The above examples illustrate that trialkyl aluminum compounds containing at least one secondary alkyl group are superior cocatalysts in ziegler-type polymerizations of alpha-olefins and that di-secondary alkyl aluminum compounds are preferred.

EXAMPLE 5 Various secondary norbornyl aluminum n-alkyl compounds were prepared by reacting the stoichiometric proportions of a norbornene compound with either i Bu2AIH or AlEt3 at elevated temperatures and removing unreacted materials by vacuum stripping. Structures were shown by 1H and 13C NMR to be the expected addition products of Al-H or Al-Et across the nobornene double bond. These mono and di-secondary alkyl aluminum compounds were used in propylene polymerization following the procedure of Example 2.

TABLE III Run Al Alkyl Rate ; Hl J 2-Norbornyl AliBu2* 344 90.2 K (2-Norbornyl)2AliBu* 247 91.8 L 3-Ethyl-2-norbornyl AlEt2* 322 92.5 M 3-Ethyl-5-ethylidene-2- 247 93.7 norbornyl AlEt2* *Other isomers may also be present.

Comparison with the AlEt3 control (Run C, Example II) shows that all of the secondary norbornyl aluminum alkyls gave markedly higher heptane insolubles while retaining high activity.

EXAMPLE 6 The procedure of Example 2 was followed except that various Lewis bases were mixed with the aluminum alkyl solution before charging to the reactor.

TABLE IV Run Al Alkyl mmoles Base Rate WO Hl T AlEt3 control 0.16 Et2O 358 84.7 U s-Bu2AlEt 0.16 Et2O 289 94.4 V t-Bu2AlEt 0.1 Me p-toluate 327 94.0 W t-Bu2AlEt 0.3 Et p-anisate 79 97.3 X t-Bu2AlEt 0.9 Et2O 56 98.0 Y t-BuAlEt2 0.9Et2O 101 97.1 Z* t-Bu2AIEt 0.2 acetophenone 196 94.2 AA* t-Bu2AlEt 0.2 ethylacetate 74 97.6 *Used catalyst preparation described in Example 6, Runs P-S.

The improved stereospecificities obtained with the cocatalysts of this invention are further increased by the addition of Lewis bases (Runs U-AA versus control runs T and Example 2, Run C). At the higher amounts of base, 97-98% HI was obtained, which is sufficiently high to eliminate the need for rejection of atactic polymer and greatly simplify the process. Activity is decreased somewhat, but it is still 3-5 times that of the Et2AICI/TiCI3 - 0.33AlCl3 commercial catalyst (rate=20, HI=93). At somewhat lower base concentrations, activity is 1020 times higher than the commercial catalyst while still achieving 1--2% higher heptane insolubles.

EXAMPLE 7 Following the procedures of Example 2 and Example 6, improved stereospecificity is also obtained using t-Bu2InEt cocatalyst.

EXAMPLE 8 The procedure of Example 2, was followed except that 9-i-Bu-9-alumino-3,3,l- bicyclononane was used as cocatalyst. The catalyst was made by ball milling 5 mol MgCl3 with 1 mole ethyl benzoate for 1 day, adding 1 mole TICS4 and milling 3 days then treating with neat TiCI4 at 80"C for 2 hours washing with heptane and vacuum dried. The catalyst contained 3.44% Ti. Polymerization rate=97.5 g/g catalyst/hour; HI=85.1%.

EXAMPLE 9 The procedure of Example 8 was followed except that t-Bu2AI (n-octyl) was used as cocatalyst. The rate was 212 g/g catalyst/hour; HI=93.0 .

Comparative Example A titanium catalyst containing MgCI2 was prepared by dry ball milling 4 days a mixture of anhydrous MgCl2 (1 mole) TiC14 (1 mole) and TiC13 (0.1 mole). The polymerizations were carried out in a 1 liter baffled resin flask fitted with an efficient reflux condenser and a high speed stirrer. In a standard procedure for propylene polymerizations, 475 ml n-heptane ( < 1 ppm water) containing 10 mmole of aluminium compound, was charged to the reactor under dry N2, heated to reaction temperature (65"C.) and saturated with pure propylene at 765 mm pressure. The supported catalyst was charged to a catalyst tube containing a stopcock and a rubber septum cap. Polymerization started when the supported catalyst was rinsed into the reactor with 25 ml n-heptane from a syringe. Propylene feed rate was adjusted to maintain an exit gas rate of 200 500 cc/min at a pressure of 765 mm. After one hour at temperature and pressure, the reactor slurry was poured into one liter isopropyl alcohol, stirred 2--4 hours, filtered, washed with alcohol and vacuum dried.

Propylene was polymerized and the quantities are shown in Table VI Activity with the cocatalysts of this invention (Run L) was intermediate between those of the AlEt3 and AlEt2CI controls (Runs J and K), but the stereospecificity as shown by % HI was much higher than the controls. The large increase in % HI obtained with this MgCl2-containing catalyst is in contrast to the results in Example 1 using TiCI3 catalysts in which activity increased sharply but % HI decreased.

TABLE VI Alkyl Rate Run Catalyst Metals g/g Cat/hr % HI J(Control) 1 10 AlEt3 79 54.4 K(Control) 1 10 AlEt2CI 18 35.8 L 0.2 1 AIEtCI2+ 42 81.0 1 (s-Bu)2Mg EXAMPLE 10 A titanium catalyst was prepared by dry ball milling 4 days a mixture of 5 MgCl2, 1 TiC14 and 1 ethyl benzoate, heating a slurry of the solids in neat TiCl4 2 hours at 800 C, washing with n-heptane and vacuum drying. The catalyst contained 3.78% Ti.

Propylene was polymerized b EXAMPLE 11 The procedure of Example 10 was followed using 0.2 g of the supported TiCI4 catalyst together with (s-Bu)2Mg and various aluminum compounds.

TABLE VIII Mmoles Mmoles Time Rate Run Al Cpd (s-Bu)2Mg Hrs. g/g Cat/hr % HI V 0.4AlEtCl2 0.33 1 - 60 94.5 W 1 AlEtCl2 0.41 1 64 76.6 X 0.5 AlEtCl2 0.83 1 260 87.2 Y 0.5 AICI3 0.83 2 136 90.7 Z I AlEtCI2+1AIEt2CI 0.83 1 404 86.9 AA 1 AlEtBr2 0.83 1 220 88.9 BB I AlC8H,7Cl2 0.83 1 425 88.0 CC 0.63 EtClAlN(iPr)2 0.53 1 6 DD 1 Br2AlN(iPr)2 0.83 1 16 Comparison of Runs V, W and X shows that the highest % HI is obtained at approximately equimolar amounts of RAIN12 and R2Mg (Run V), that a large excess of RAICI2 is undesirable (Run W) and that a small excess of R2Mg increases activity (Run X). Activity also increased upon addition of AlEt2CI to the AlEtCI2 (s-Bu)2Mg system (Run Z). The remainder of the experiments show that the dibromide may be used in place of dichloride (Run AA), that long chain alkyl aluminum compounds are very effective (Run BB), but that dialkyl amide groups on the aluminum compound destroy catalyst activity (Runs CC and DD which are included by way of comparison).

EXAMPLE 12 The procedure of Example 10, Run T was followed except that Lewis bases were also added to the AlEtCl2-(s-Bu)2Mg cocatalysts.

Addition of Lewis bases causes a decrease in catalyst activity until it becomes zero at a mole ratio of one strong base per mole of RAICI2+R2Mg (Table IX).

TABLE IX Rate Run Mmoles Base/(sec Bu)2Mg Time, Hrs g/g Cat/hr % HI EE 0.24 COOEt'a' 0.5 174 94.3 FF 0.5Et3Nb 1 62 85.5 GG 2 diisopentyl ether 1 127 78.8 HH 2 Tetrahydrofiran(C 1 0 (a) Added to the (s-Bu)2Mg (b) Premixed total catalyst in 100 ml n-heptane at 650C, 5 min. before adding Et3N (c) Added to premixed AlEtCl2-(s-Bu)2Mg As shown in Run EE, small quantities of Lewis base are effective in improving isotacticity (94.3% HI vs. 91.9 in Run T) while maintaining high activity.

EXAMPLE 13 The procedure of Example 10, Run T was followed except that xylene diluent was used for polymerization instead of n-heptane. Activity was 676 g/g Cat/hr and the polymer gave 90.9% heptane insolubles. The polymer was precipitated with 1 liter isopropyl alcohol, filtered, dried and analyzed for metals. Found 13 ppm Ti and 83 ppm Mg. Thus at high monomer concentration and longer polymerization times the high efficiency would yield very low catalyst residues without deashing.

EXAMPLE 14 The procedure of Example 10, Run T was followed except that polymerization was carried out at 500C and 80"C. Both polymerization rate and % HI decreased with increasing temperature, with the largest decrease taking place above 65"C (Table X).

TABLE X Polymer Time Run Temp, OC Hours Rate % HI II 50 1 474 90.4 T 65 1 367 91.9 JJ 80 0.5 148 74.6 EXAMPLE 15 Propylene was polymerized at 690 kPa pressure in a stirred autoclave at 500 C, I hour. A second preparation of MgCl2-containing TiCl4 catalyst (2.68% Ti), made as in Example 10 except that TiCl4-ethylbenzoate complex was preformed, was used in combination with AlRCI2-R2Mg. High stereospecificity was obtained at high rates and catalyst efficiencies (Table XI).

TABLE XI g Mmoles Mmoles Run Cat AlEtCl2 (s-Bu2)Mg Rate % HI KK 0.10 0.5 0.5 1672 88.8 LL 0.10 0.25 0.25 696 95.0 EXAMPLE 16 The procedure of Example 10, Run T was followed except that the catalyst of Example 15 was used and 1 mmole di-n-hexyl magnesium was used instead of 0.83 mmole (s-Bu)2Mg. The (n-hexyl)2Mg in Soltrol No. 10 was obtained from Ethyl Corporation (Lot No. BR-516). Polymerization rate was 551 g/g Cat/hr but the polymer gave 76.9% HI which is unexceptable. Thus n-alkyl magnesium compounds do not yield the high stereospecificity of the secondary and tertiary alkyl compounds of this invention.

EXAMPLE 17 The procedure of Example 12 Run EE was followed except that a new pure sample of (sec-Bu)2Mg was used with 0.33 mole diethyl ether instead of ethyl benzoate and the reaction time was 1 hr. Rate was 268 g/g Cat/hr and % HI=92.2.

EXAMPLE 18 A catalyst was prepared by dry ball milling for 4 days a mixture of 10 MgCl2, 2 TiCI4, 2 ethylbenzoate and 1 Mg powder, heating the solids in neat TiCI4 2 hours at 80"C, washing with n-heptane and vacuum drying (Ti=2.16%).

Propylene was polymerized 1 hour at 650C and atmospheric pressure using 0.20 g of this catalyst under the conditions of Example 10, Run T except only 0.4 mmole (s-Bu)2Mg and 0.4 mmole AlEtCI2 was used. Rate was 240 g/g Cat/hr and % HI=93.9.

EXAMPLE 19 A catalyst was prepared by dry ball milling for 1 day a mixture of 5 MgCI2 and 1 ethylbenzoate, adding 1 TiCI4 and milling an additional 3 days, then treating the solids with neat TiCI4 2 hours at 800C, washing with n-heptane and vacuum drying (3.44% Ti).

Propylene was polymerized following the procedure of Example 10, Run T, except that 1 mmole (s-Bu)2Mg was used instead of 0.83 mmole. Rate was 298 g/g Cat/hr and % HI=89.

EXAMPLE 20 Following the procedure in Example 15, two catalysts were made at different Mg/Ti ratios. Catalyst A was made with 1 MgCI2+1 TiCl4-ethylbenzoate and B (2.10% Ti) was made with 10 MgCl2+l TiCl4-ethylbenzoate complex. Propylene was polymerized following the procedure of Example 10, Run T (Table XII).

TABLE XII g Mmoles Mmoles Run Cat AIEtCI2 (s-Bu)2Mg Rate % HI MM 0.107A 2 1.66 60 72.0 NN 0.316B 0.25 0.25 512 60.4 OO(a 0.316B 0.25 0.25 124 84.2 (a) Added 0.25 mmole triethylamine to the alkyl metal cocatalysts.

These results show that the 1:1 and 10:1 MgCl2:TiCl4 catalyst preparations were not as effective as the 5:1 preparations in preceding examples.

EXAMPLE 21 Polymerizations were carried out in a 1 liter baffled resin flask fitted with a reflux condenser and stirrer. In a standard procedure for propylene polymerizations, 475 ml n-heptane ( < 1 ppm water) containing the alkyl metal cocatalysts was charged to the reactor under N2, heated to reaction temperature (65 C) while saturating with propylene at 765 mm pressure. The powdered transition metal catalyst was charged to a catalyst tube such that it could be rinsed into the reactor with 25 ml n-heptane from a syringe. The propylene feed rate was adjusted to maintain an exit gas rate of 200500 cc/min. After one hour at temperature and pressure, the reactor slurry was poured into 1 liter isopropyl alcohol, stirred 2-4 hours, filtered, washed with alcohol and vacuum dried.

A titanium catalyst supported on MgCl2 was prepared by combining 5 moles MgCl2, I mole TiCl4 and 1 mole ethylbenzoate, dry ball milling 4 days, heating a slurry of the solids in neat TiCl4 2 hours at 800 C, washing with n-heptane and vacuum drying. The catalyst contained 3.78% Ti. Portions of this catalyst preparation were used in the experiments shown in Table XIII. Various control runs are shown for comparison with the cocatalysts of this invention (Runs A-F).

The sec-butyl magnesium was obtained from Orgmet and contained 72% non volatile material in excess of the s-Bu2Mg determined by titration. IR, NMR and GC analyses showed the presence of butoxide groups and 0.07 mole diethyl ether per s-Bu2Mg. The various s-BuMgX compounds were prepared directly by reacting an equimolar amount of ROH, RSH, RCOOH, etc. with the s-Bu2Mg.

TABLE XIII (0.2 g Catalyst, 500 ml n-C7, 65 C., 1 hr.) Mmoles Mmoles Mmoles Rate Run Al Cpd Mg Cpd Base g/g Cat/hr % HI Control 1 AlEt2Cl - 47 67.1 Control 1 AlEt3 - 326 82.6 Control 1 AlEt2Cl 0.83 (s-Bu)2Mg - 165 80.5 Control 1 AlEt3 0.83 (s-Bu)2Mg - 6 Control - 0.83 (s-Bu)2Mg - 0 - Control - 0.83 s-BuMgCl - 0 - A 1 AlEt2Cl I s-Bu Mg OOC0 - 165 95.2 B 1 AlEt2Cl l-s-Bu Mg OC15H31 - 276 91.7 C 1 AlEt2Cl 1 s-Bu MgOC2Hs - 261 91.4 D 1 AlEt2Cl I s-Bu MgSC12H2s - 310 93.2 E 1 AlEt2Cl 0.83 s-Bu MgCI 1 Et3N 100 94.6 F 1 Et2AlOOC 1 s-BuMgCl - 351 90.5 + 1 Et (s-Bu)AlCl Compared to the control runs, which gave either low activity or low percent heptane insolubles (% HI), the new cocatalyst combinations gave high activity and stereospecificity ( > 90% HI).

EXAMPLE 22 A second catalyst preparation 2.68% Ti was made following the procedure of Example 21 except that a preformed 1:1 complex of TiCl4 # OCOOEt was used. In Runs G and H, the s-BuMgCl. Et2O was obtained by vacuum stripping an ether solution of the Grignard reagent. In Run I, the n+s BuMgOOCC6H5 was made by reacting pure (n+s Bu)2Mg with benzoic acid. Propylene polymerizations were carried out as in Example 21 (Table XIV).

TABLE XIV Mmoles Mmoles Mmoles Rate Run Al Cpd Mg cpd Base g/g Cat/hr. 0,c/ HI G 1 AlEtCl2 1 s-BuMgCl I Et2O 0 - H 1 AlEt2Cl 1 s-BuMgCl I Et2O 132 93.1 I 1 AlEt3 1 n+s-Bu - 123 89.7 MgOOCCsH5 Run G which is by way of comparison shows that monoalkyl aluminum compounds are not effective in combination with the mono-organo-magnesium compounds in this invention. In contrast, Example 10, Run T, shows that such monoalkyl aluminum compounds are preferred when diorganomagnesium compounds are used.

Runs H and I show that dialkyl and trialkyl aluminum compounds are required with monoalkyl magnesium compounds.

EXAMPLE 23 Propylene was polymerized at 690 kPa pressure in a 1 liter stirred autoclave at 50"C. for 1 hour using the supported TiCl4 catalyst of Example 22 (Table XIV). The Mg compound was made as in Example 21, Run A.

TABLE XV g. Mmoles Mmoles Run Cat Mg Cpd AlEt2Cl Solvent Rate % HI J 0.05 0.5 s-BuMgOOC 0.5 n-C7 1292 89.9 K 0.10 0.4 s-BuMgOOCB 0.4 n-C7 317 96.9 L 0.10 0.4 s-BuMg OOC 0.4 Xylene 517 96.5 Comparison of Runs J and K shows that the lower alkyl metal/catalyst ratio in K gave higher heptane insolubles. Run L in xylene diluent gave higher activity than K in heptane.

EXAMPLE 24 The procedure of Example 22 was followed except that organo-magnesium compounds containing alkoxy and benzoate groups were used in combination with AlEt2CI together with diethyl ether. The s-BuMgOsBu was prepared by reacting a dilute solution of sBu2Mg containing 0.33 Et2O with one mole s-BuOH and used without isolation (Run M). The mixture in Run N was prepared in a similar manner by reacting 1.55 mmole n+s Bu2Mg with 1.10 s-butanol, adding 0.066 Et2O, then adding this product to a solution of 1 benzoic acid in 275 ml n-heptane.

TABLE XVI Mmoles Mmoles Mmoles Run Mg Cpd AlEt2CI Et2O Rate % HI M 1 s-BuMgOs-Bu 1 1/3 107 94.6 N 0.45 n+s BuMg OOC 1 0.0006 101 95.9 0.55 n+s BuMgOsBu 0.55 s BuOMgOOC Comparison with Example 22, Run H shows that superior results were obtained with smaller amounts of diethyl ether by using alkoxide and carboxylate salts instead of the chloride.

EXAMPLE 25 The procedure of Example 6 Run Z was followed except that 0.25 mmole Mg(OOCC6Hs)2 was used in place of acetophenone as the third component. The magnesium benzoate was prepared from a dilute heptane solution of benzoic acid and n+s Bu2Mg. The t-Bu2AlEt was added to the milky slurry of Mg(OOCC6H5)2, charged to the reactor and heated to 650C, 5 min., after which the supported titanium catalyst was added.

The propylene polymerization rate was 122 g/g-cat/hr and polymer HI=97.7%.

WHAT WE CLAIM IS: 1. A catalyst composition suitable for use in alpha-olefin polymerization which comprises a mixture of: (a) Group IVA to VIII transition metal halide on a crystalline chloride layer lattice compound (as hereinbefore defined) support; (b) at least one organo metal compound of the formula: RnMR'3n wherein R' is a C1 to C20 primary group, said group being alkyl, alkenyl or aralkyl, R is a Ca to C20 secondary or tertiary group, said group being alkyl, cycloalkyl, alkenyl or aralkyl, M is aluminium, gallium or indium and n=l to 3, and

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (16)

**WARNING** start of CLMS field may overlap end of DESC **. Run G which is by way of comparison shows that monoalkyl aluminum compounds are not effective in combination with the mono-organo-magnesium compounds in this invention. In contrast, Example 10, Run T, shows that such monoalkyl aluminum compounds are preferred when diorganomagnesium compounds are used. Runs H and I show that dialkyl and trialkyl aluminum compounds are required with monoalkyl magnesium compounds. EXAMPLE 23 Propylene was polymerized at 690 kPa pressure in a 1 liter stirred autoclave at 50"C. for 1 hour using the supported TiCl4 catalyst of Example 22 (Table XIV). The Mg compound was made as in Example 21, Run A. TABLE XV g. Mmoles Mmoles Run Cat Mg Cpd AlEt2Cl Solvent Rate % HI J 0.05 0.5 s-BuMgOOC 0.5 n-C7 1292 89.9 K 0.10 0.4 s-BuMgOOCB 0.4 n-C7 317 96.9 L 0.10 0.4 s-BuMg OOC 0.4 Xylene 517 96.5 Comparison of Runs J and K shows that the lower alkyl metal/catalyst ratio in K gave higher heptane insolubles. Run L in xylene diluent gave higher activity than K in heptane. EXAMPLE 24 The procedure of Example 22 was followed except that organo-magnesium compounds containing alkoxy and benzoate groups were used in combination with AlEt2CI together with diethyl ether. The s-BuMgOsBu was prepared by reacting a dilute solution of sBu2Mg containing 0.33 Et2O with one mole s-BuOH and used without isolation (Run M). The mixture in Run N was prepared in a similar manner by reacting 1.55 mmole n+s Bu2Mg with 1.10 s-butanol, adding 0.066 Et2O, then adding this product to a solution of 1 benzoic acid in 275 ml n-heptane. TABLE XVI Mmoles Mmoles Mmoles Run Mg Cpd AlEt2CI Et2O Rate % HI M 1 s-BuMgOs-Bu 1 1/3 107 94.6 N 0.45 n+s BuMg OOC 1 0.0006 101 95.9 0.55 n+s BuMgOsBu 0.55 s BuOMgOOC Comparison with Example 22, Run H shows that superior results were obtained with smaller amounts of diethyl ether by using alkoxide and carboxylate salts instead of the chloride. EXAMPLE 25 The procedure of Example 6 Run Z was followed except that 0.25 mmole Mg(OOCC6Hs)2 was used in place of acetophenone as the third component. The magnesium benzoate was prepared from a dilute heptane solution of benzoic acid and n+s Bu2Mg. The t-Bu2AlEt was added to the milky slurry of Mg(OOCC6H5)2, charged to the reactor and heated to 650C, 5 min., after which the supported titanium catalyst was added. The propylene polymerization rate was 122 g/g-cat/hr and polymer HI=97.7%. WHAT WE CLAIM IS:

1. A catalyst composition suitable for use in alpha-olefin polymerization which comprises a mixture of: (a) Group IVA to VIII transition metal halide on a crystalline chloride layer lattice compound (as hereinbefore defined) support; (b) at least one organo metal compound of the formula: RnMR'3n wherein R' is a C1 to C20 primary group, said group being alkyl, alkenyl or aralkyl, R is a Ca to C20 secondary or tertiary group, said group being alkyl, cycloalkyl, alkenyl or aralkyl, M is aluminium, gallium or indium and n=l to 3, and

(c) at least one Lewis base.

2. A composition according to claim I wherein the halide of said transition metal halide is chloride, bromide or a mixture thereof.

3. A composition according to either of claims 1 and 2 wherein the metal of said transition metal halide is trivalent titanium, trivalent vanadium or tetravalent titanium.

4. A composition according to claim 1 wherein said transition metal halide is Tic4.

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5. A composition according to claim 1, wherein said transition metal halide is TiCI3.

6. A composition according to claim 1 wherein said transition metal halide is a mixture of TiCI3 and TiCI4.

7. A composition according to any one of the preceding claims wherein said support contains MgCl2.

8. A composition according to any one of the preceding claims, wherein said Lewis base is an amine, an ester, a phosphine, a phosphine oxide, a phosphate, an amide, a ketone or an ether.

9. A composition according to claim 8 wherein said Lewis base is a carboxylic acid ester.

10. A composition according to any one of the preceding claims, wherein the molar ratio of said organo metal compound to said transition metal halide is from 0.5:1 to 50:1.

11. A composition according to any one of the preceding claims, wherein n equals 1.

12. A composition according to any one of claims 1 to 10 wherein n equals 2.

13. A composition according to claim 11 wherein RMR'2 is formed from the reaction product of R'2MX and RMgX', wherein X is chloride, bromide or a monovalent anión which cannot initiate polymerization of olefinic monomers and X' is an anion which cannot initiate polymerization of olefinic monomers.

14. A composition according to claim 12 wherein R2RM' is formed from the reaction product of R Mg and R'MX2, wherein X is chloride, bromide or a monovalent anion which cannot initiate polymerization of olefinic monomers.

15. A process for the polymerization of an alpha-olefinic C2 to C20 monomer or a mixture thereof to a solid homo-, co- or terpolymer by contacting said monomer with a catalyst composition according to any one of the preceding claims at a temperature of 25"C to 1 500C, a pressure of 1 atm. to 50 atm. for a time of 0.1 to 10 hours.

16. A homo-, co- or terpolymer whenever prepared by a process according to claim 15.