DE1963256A1 - Polymerization catalyst and process for its preparation - Google Patents

Description

Br. W ₉ Schalk, Dipl.-Ing. F. Wirth, Dipl.-Ing. β «Dannenberg Drο Vo Schmied-Kowareik, Dr ₀ P ₃ Weinhold, Dr ₀ D _e Gudel

6 Frankfurt am Main Gr. Eschenheimer Str. 39 Hn / hn

P 7531-C

Union Carbide Corporation

27Ο Park Avenue

New York. N ₀ Y ₀ 10 017 / üSA Polymerization catalyst and process for its Manufacturing

The invention relates to a catalyst for the polymerization von Äthylen Eur Manufacture of ethylene homopolymers and Copolymers of ethylene with other α-olefins and / or Diolefineno

From US Pat. No. 3,379,706 it is known that certain

TT-Ally! -Metal compounds are active polymerization, especially oligomerization catalysts. With regard to the polymerization of ethylene, it is stated therein that tris-if-allyl- λ chromC TT-allylchrom (III)) polymerizes ethylene with the formation of linear polyethylenes with I; R. -Spectra which are identical to the spectra of the so-called Ziegler polyethylenes, these linear polyethylenes, however, in a yield in the order of magnitude of only 5 to 36 g of polymer per gram of chromium. per hour. ,

It has now been found that when an allyl chromium compound is used in the catalytic polymerization of ethylene, the yield can be increased by 1 million% if one. al

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lyst a TT-Allylchrom (lII) complex used in the asm chromium has been at least partially reduced to the divalent chromium, and the isto supported on a carrier of an inorganic oxide having a large surface or deposited

Another object of the invention is a process for the production of a TT-allylchromium catalyst with a high Activity, which is characterized in that a TT-AlIy 1-chromium (III) compound at least partially converted into the chromium (II) compound and the reduced TT-allylchromium compound deposited on or adsorbed on an inorganic oxide with a large surface area.

When reducing at least part of a JT allyl chromium (III) compound to a chromium (II) compound and during application the reduced allyl chromium compound to an inorganic oxide having a large surface area according to the method of the invention an ethylene polymerization catalyst having an unusually high productivity is obtained.

The TT-Allylchromkomplexe used to prepare the catalysts of the invention are usually prepared by reacting chromium trichloride at temperatures below about -17 ⁰ C and allylmagnesium bromide. A suitable process for the preparation of these TT-allylchromium complexes is described by Kurras and Klinisch in monthly report., German. Akad. D. Wies., Berlin, 6, 736 (1964). The thus prepared Allylchrom (III) complexes are stable in solution at temperatures below about -17 ⁰ C, but at higher temperatures they are transformed into complexes in which the chromium is present in a lower valence state.

When examining the suitability of the TT-allylchromium complexes alß Ethylene polymerization catalysts have been determined which Influence the use of a carrier made of an inert inorganic oxide on the catalytic activity has ο When a sample

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a fairly fresh stock solution of "jr-allyl chromium on a silica gel support with a large surface area which had previously been activated at 580 ° C was adsorbed and when this supported compound was used as an ethylene polymerization catalyst, the normal ethylene polymerization temperatures practically only occurred dimerization of ethylene to Butsnen and some higher olefins, even when the Allylchrom (III) polymerization = "temperatures has been exposed to over 70 ⁰ C is applied to a substrate _o this is remarkable, since the dimerization of ethylene so far only with the use of aluminum alkyls as catalysts rather than organic chromium compound catalysts ₀

Λ If the stock solution was then allowed to warm to room temperature ^ and it was kept at room temperature for about 10 minutes, a precipitate was observed which indicated the reduction of the chromium to a lower valence ο If then a sample of this solution on a silica gel carrier with a large surface , which had previously been ^{activated at 35O 0} C, was adsorbed, the allyl chromium compound was surprisingly highly active for the polymerization of ethylene to polymers with a high molecular weight and a high density, the I ₀ R ₀ spectra of the IR "spectra of the so-called Ziegler polyethylene were completely different.

Even more surprising was the considerable increase in the productivity of the catalysts applied to a carrier. In comparison to the highest productivity of 36 g polymer per gram of chromium per hour known from US Pat. No. 3,379,706, it was now possible with the help of the Catalysts according to the invention applied to supports achieve a yield of about 400,000 g of polymer per gram of chromium per hour. This corresponds to a yield improvement in the order of magnitude of over 1 million% _o

Without wishing to be bound by any particular theory, it is believed that the f "-Allylchrom (III) in solution to an active

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Form is reduced »which must be present if the adsorption on the inorganic oxide took place. It is assumed that this active form is Tr-allylchromium (II), which is the first in the reduction of T-allylchromium (III) Complex is formed, and it is also believed that this was in the form of a dimer consisting of two chromium atoms and four allyl groups. Allylchrome (III) is in a dynamic equilibrium with complexes in which the chromium is present in an even lower valence level, which is presumably formed in a further reduction of the T-allylchrome (II) ο An indication of this is the observation that, when the reduction once started and the solution _(was repeatedly heated to about 5 ° C for short periods of time to take samples for the preparation of the supported catalyst, the solution after a period of about 2 weeks seemed to have reached a state which gave a supported catalyst with the highest productivity, while thereafter the supported catalysts showed progressively lower productivities »

It is also noteworthy _s that mere adsorption is not the normal way of producing a highly active Äthylenpolymerisationskatalysators a T ~ -Allylchromkomplexes to a carrier, since it was found that it does not receive any polymers having a high molecular weight, when the adsorbed on the carrier TT -AllylchromCIII) compound exposed to elevated temperatures, as they usually occur in Niederdruckäthylenpolymerisations, To prepare an active catalyst with a high productivity, it is rather necessary to reduce the compound before or after the deposition on the support.

As already stated above, for the production of T-allylchromium (III) only about 1 to about 30 minutes of simple heating to deposit to form an active catalyst

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required to room temperature, the reduction to the active form will be indicated by the formation of an inactive by-product precipitate When this precipitation occurs, the solution can fully consumed or storage to a low temperature in the order of about -78 ⁰ C brought "It has generally been found that in the event that the solution is partially consumed using processes which require a temperature increase to avoid moisture condensation, aging continues and finally after about 15 or more recycles to temperatures above about -17 ⁰ C, which is normally for TT-AllylchromClII) and probably also for the complexes with a lower valence level normally acceptable minimum reduction temperature »led to a possible loss of activity

Although the conversion of T-allylchrome (III) to T-allylchrome (II) complex takes place within a certain time at room temperature, this conversion can also take place at other temperatures, from about -I7 to about 80 ° C, as long as the There was enough time for the reduction to take place. Let it be at this point once again pointed out that the reduction can be followed on the basis of the formation of the precipitate.

For making the fully active catalyst of the invention the reduced ΤΓ-allylchrome complex with a practical brought into contact with anhydrous inorganic oxide and deposited thereon or adsorbed on it. Examples for the various inorganic oxides useful for preparing the supported catalyst Silicon dioxide, aluminum oxide, thorium dioxide, zirconium dioxide and comparable oxides and mixtures thereof, in particular Silicon dioxide-aluminum oxide mixtures, all of these carriers being chemically inert to the T-allylchromium complex and do not reduce its activity. These supports, if they are to be effective, have to have a large surface for adsorption a sufficient amount of the ir-allylchrome complex and aur

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Ensure sufficient contact between the catalyst and the monomer _o Is the general rule _? dai3 inorganic oxides with a surface area in the range

from about 50 to about 1,000 m per gram as a catalyst support . should be used »The particle size of these carriers is not particularly critical, provided, however, that the carrier

has a large surface area.

In order to produce a suitable catalyst, the support should be completely dry before it is exposed to the organochromium compound is brought into contact »This is normally done by simply heating or pre-drying the catalyst carrier with an inert gas before use.

In some respects, the drying temperature can be both on the level of the relative productivity value of the catalyst as well as have an influence on the molecular weight distribution and the Sehmelzindex of the polymer formed.

The carrier can be dried or activated at almost any temperature up to about the sintering temperature of the carrier for a period of time at least sufficient to remove the adsorbed water, but avoiding all chemically bound water when heated is removed «, the passage of a stream of inert gas through the carrier during drying also contributes, if desired, to the displacement of the adsorbed water. Temperatures within the range of about 20O ⁰ C to about 90O ⁰ C within a short period of about 6 hours or the like are sufficient if a well-dried inert gas is used and the temperature is not allowed to rise to such a value that the chemically bound Hydroxyl groups on the surface of the carrier are completely removed »

Any kind of carrier can be used, small spherical ones Medium Bisbte Silicon Dioxide (MSID) with a surface area of 258 m per gram and a pore diameter of about 200 Å and silicon dioxide of a medium one

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Density (ID) with the same surface size, but a pore diameter of about 164 S. However, other types are preferred, such as Z ₀ B, the G-968 silicon dioxide and the G-966 silicon dioxide-aluminum oxide (that's the name of the Company W ₀ R ₀ Grace and Co.) with surface sizes of 700 or 500 a per gram and pore diameters γοη 50 to 70 α are also completely satisfactory. Changes in melt index control and in the level of polymer productivity value can occur between different types of carrier and also as a result of the use of different activation temperatures.

After the supported T-allyl chromium catalyst is prepared, the polymerization reaction takes place carried out by ethylene alone or together with other olefins copolymerized therewith, practically in the absence of moisture and air at a temperature and pressure sufficient to initiate the polymerization reaction initiate, with a catalytic! (Close the catalyst brings into contact ο if desired, an inert organic Solvents can be used as a diluent and to facilitate handling of the materials.

The polymerization reaction takes place at temperatures of about 30 ^° C. or less up to about 200 ^° C. or more, depending on the altitude the operating pressure, the pressure of the olefin monomers possibly present other than ethylene, the pressure of the modifying gas possibly present in the system and depending on the particular catalyst and its concentration ”. Of course, the selected working temperature also depends on the desired polymer melt index, since this temperature is definitely a factor for regulating the molecular weight of the polymer The temperature is preferably within the range from about 30 to about 100 ^° C. for the polymerization in solution (solution formation process)

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they are within the range of 100 to 200 ⁰ C ₀ ethylene polymers with low density are produced by polymerisation in solution o Ethylene homopolymers with low density can also be produced by mass polymerisation (particle formation process) if the activation temperature of the carrier is 58O ⁰ C or 420 ⁰ C in the production of ethylene copolymers., The regulation of the temperature is useful in this process, which is explained in more detail below, so that various effects on the molecular weight of the polymers and on the regulation of the phase in which they are produced can be achieved _o In most catalyst systems, the use of higher temperatures leads to the formation of polymers with a lower average molecular weight and consequently to polymers with a higher melt index "

The pressure used can be any pressure sufficient to initiate the polymerization of the monomer to form a high molecular weight polymer (1,000,000 psig) or more, but the pressure is preferably within the range of atmospheric pressure up to about 7113 kg / cm (1,000 psig) c Generally a pressure of 2.4-1 to 57.2 kg / cm cm ² (20 to 800 psig) preferred "As can be seen from the explanation in this regard and the examples below, the pressure can be varied within a wide range in order to obtain polymers with a high molecular weight"

The selection of the one to be used in the method of the invention Inert organic solvent medium is not very critical, but the solvent must be inert to that on a support applied TP ^ allyl chromium catalyst and compared to the formed olefin polymer and it must be used in the Be resistant to heating temperature »It is not necessary, however, that the inert organic solvent medium too

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“Examples of inert organic solvents which can be used for this purpose are saturated aliphatic hydrocarbons, ζ serves as the solvent for the polymer formed. Β. Hexane, heptane, pentane, isooctane, purified kerosene and the like, saturated cycloaliphatic hydrocarbons, e.g. B ₀ cyclohexane, cyclopentane, dimethylcyclopentane, methylcyclohexane and the like, aromatic hydrocarbons, Z ₀ B ₀ benzene, toluene, xylene and the like, and chlorinated hydrocarbons For example, chlorobenzene, tetrachlorethylene, o-dichlorobenzene and the like «. Particularly preferred solvent media are cyclohexane, pentane, hexane and heptane.

If it is desired to conduct the polymerization to a high level of contaminants as described above, it is natural It is advisable to use a solvent that is liquid at the reaction temperature ο For example, when working at a temperature below the solution temperature dee Polymer in the solvent, the process is essentially a slurry or suspension polymerization process be in which the polymer actually precipitates from the liquid reaction medium and in which the catalyst in fine divided form is suspended "

Bas slurry system of course depends on the solvent used in the poly »polymerization each solvent and the Lösunga- λ temperature of the solvent for the polymer formed from" Consequently, it is very convenient to operate the polymerization in "particle ¹ * at a temperature which is below the normal Löeungstemperatur of the polymer in the chosen solvent is ₀ Thus, for example, thereby obtaining · polyethylene, a solution temperature in cyclohexane of about 9O ⁰ O while its Lösungetemperatur in pentane is about 110 ⁰ O ₀ It is characteristic of this ^fl particulate "-Polyaeriaationaaystem that it is then possible to achieve a high polymer solids content even at low temperatures, but the prerequisite is that stirring is carried out in order to mix the monomer well with the polymerizing mass.

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- ίο -

that although the rate of polymerization at these. lower temperatures, the monomer in the Solvent! Medium is more soluble and so is the tendency counteracts low polymerization rates and / or low yields of polymer "

It is also characteristic that the monomer has a substantial solubility even in the Peststoffanteil the slurry so that _$ Stirring is continued and the polymerization temperatures are maintained can be obtained a wide range of the size of the Peststoffteilchen in the slurry "It has been shown _t that greater than 50% solids system can be achieved when polymerizing in a slurry if sufficient fluidizing conditions are maintained and sufficient agitation is used. It is particularly preferred to conduct the slurry within a range of 30 to 40 wt% _o Polymerisatfeststoffen O

The polymer is obtained from the solvent medium by simple filtration and drying and the polymer does not need to be cleaned, just as the catalyst does not need to be separated or cleaned. The catalyst concentration remaining in the polymer is so low that it is generally less than 2 to 3 ppm Contains chromium and such contents in the polymer are harmless and irrelevant. As a result, they can in that Polymer remain.

When working at temperatures which are higher than the solution temperature of the polymer in the selected solvent medium, a higher polymer solids content can also be achieved in solution. The temperature used in this embodiment of the invention must be sufficiently high so that the solvent sum Dissolving at least 25 to 30% by weight of the polymer can be used * On the other hand, the temperature must be sufficiently low to prevent thermal decomposition

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to avoid dee formed polymer and the catalyst. It has been shown that the optimum temperatures when carrying out the polymerization in solution for the various solvents used and the T-allylohrome catalyst are generally within the range from about 100 to about 200.degree. C., preferably within the range from about 120 to about −70 ⁰ C. The respective polymer thus formed has, however, also be applied a substantial influence on the optimum temperature "Thus produced by these processes ethylene-propylene Hischpolymerisate in many of these organic solvents at low temperatures are, for example soluble and can therefore such temperatures who« _a the, even if these temperatures are not desired for the optimal production of ethylene homopolymers or other copolymers »

Solvents are one of the most important and well-known sources of catalyst poisoning. It was also thought to be in the previous solution polymerization processes in which catalysts containing a transition metal were used, when necessary, large amounts of solvent, d. h »a solvent: polymer weight ratio of the order of magnitude of 20: 1, see below. These large amounts of solvent necessarily greatly exacerbated the problem of catalyst poisoning > In the polymerization process described here, in which the catalyst according to the invention is used, I however, the solvent: polymer ratio can be 1: 1 or even less, without this resulting in the very high value the catalyst productivity and efficiency for the system will be adversely affected.

If the solvent is used as the main reaction medium, it is of course expedient to add this practically anhydrous and free from any possible catalyst poisons . keep by repeatedly distilling or otherwise purifying it prior to use in the polymerization process. All favorable see the treatment with an absorbent with a large one

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Surface, z _o B ₀ with various silicon dioxides, aluminum oxides, molecular sieves and similar materials for removing traces of impurities, which can reduce the rate of polymerization or poison the catalyst during the reaction, have been shown.

However, it is also possible _o carry out, if desired, the Polyaerisationereaktion even without the addition of solvent reaction medium For example, themselves serve as the reaction medium, the liquid monomers, for example, the usually the commercially available liquid monomers in the preparation of ethylene-propylene copolymers using liquefied propylene and other similar, commercially available liquefied monomers, or when operating under sufficient pressure to liquefy a normally gaseous monomer e «

The fact that the rate of polymerization remains high even at the high viscosities which occur at high solids contents is very surprising. It is particularly surprising that the reaction rate remains high even then, such _o be used when normally gaseous monomers B ₀ ethylene and propylene. It has been found, however, that high rates of polymerization can be maintained even when using these gaseous monomers at pressures below 100 psig when the reaction solution is stirred with a high-speed, high-shear stirrer, particularly a stirrer that works with is driven at a speed of over 2,000 rpm and that is capable of imparting considerable shear to the solution * u is agitated *

Another particularly important advantage that can be achieved in this process when using the catalyst according to the invention is that the solution with a high content of solid polymer after completion of the polymerization reaction without further treatment to isolate the polymer

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ORIGINAL SUS

196325G

by grinding processes as they are "for example in the USA patent" 2 434 707 are described, is suitable »

Another advantage of this process is that the catalyst and the polymer formed are in homogeneous solution are maintained in the solvent medium. If you avoid the formation of a polymer suspension, the behaves Reaction mass like a viscous liquid that is pumped and can be handled according to the known standard procedures for handling liquids ο

Because the polymer is soluble in the diluent is, there is also the further advantage that high reaction temperatures can be used »This is advantageous because the high temperatures reduce the viscosity of the solution · They also accelerate the polymerization and, due to the large temperature difference between the reactor and the cooling water, enable a more effective one Elimination of the heat of reaction and also a regulation of the molecular weight of the polymer, since high temperatures in the generally lead to the formation of polymers with a lower molecular weight «.

The separation of the polymer from the solvent medium is not limited to the use of a high shear mill, although a Marshall mill has been found to be very suitable for this application and is also preferably used However, it is also possible to obtain the polymer Apply filtration process or the polymer-solvent Masee by rapid evaporation or with the help of another Concentrate the solvent removal device and then grind it in a high-shear mill. A number of other suitable mills with high shear action are commercially available and because of the low solvent content of the solution to be treated, other devices such as ventilated extruders, calendering whale mills, planetary gear rotor mills, such as those for example

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in U.S. Patent 3,075,7 * 7, Banbury mills and the like for isolating the polymer product As used herein, the term "high shear mill" means a mill consisting of parallel rollers with interlocking threads, and the term "high seer conditions" and "High shear" refers to those conditions that are achieved with the aid of a high-shear mill or a suitably driven high-speed mixer for viscous materials.

Of course, the systems can have a high solids content can also be used with a catalyst suspended in the solvent, provided that the required stirring, Conditions of pressure, temperature and the like exist to bring the monomer into contact with the catalyst, and that the pressure and the temperature are regulated so that the polymerization of the monomer to the desired polymer is initiated »

Of course, the process for plumbing the solid catalyst bed in a gaseous system by melting the bed together with a gaseous olefin feed, whereby the use of liquid solvents and the above-mentioned, related problems of solvent separation and catalyst poisoning, are within the scope of the present invention _O

The level of concentration of the Tr-allylchroacatalyst according to the invention applied to a carrier and used in this process is not critical and generally only influences the rate of formation and the yield of the polymer obtained. They may be about 100 00o _1, preferably from about 1 ppm to about 25,000 catalyst, based on the weight of the olefins used varies within a range of about 1 Wa. In the preferred and economical form of the thermoset, the catalyst concentration is about 5 to 10

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ORIGINAL INSPECTED

i9632 € G

about 100 ppm "The lower the content of impurities in the reaction system, the lower the catalyst concentration to be used can obviously be". It has been shown that yields of more than 400,000 g of polymer can be obtained per gram of chromium. This is surprising since US Pat. No. 3,379,706 only gives yields of 36 g of polymer per gram of chromium; as will be explained hereinbelow, an applied on a support according to the invention catalyst made from a mixture of Allylchrom (II) with AllylchromClII) and on a more than 400 ⁰ C and preferably ⁰ ^ 58o C activated silica gel

was precipitated, a considerable oligomerization of m ethylene with butenes and some higher olefins

The α-olefins which can be polymerized with ethylene using the catalyst of the present invention include those containing 3 to about 10 carbon atoms. Examples of such oc-olefins are: propylene, butene-1, pentene-1, 3-methylbutene-1, hexene-1, 4-methylpentene-1, 3-ethylbutene-1, heptene-1, octene-1, decene 1,4-dimethylpentene-1, 4,4-diethylhexene-1, 3,4-dimethylhexene-1, 4-butyl-1-octene, 5-ethyl-i-decene and 3t3-dimethylbutene-1. These compounds can be polymerized together with a large amount of ethylene to form normally solid copolymers of ethylene with one or more of these high molecular weight ot-olefins. Ä Ethylene can also be polymerized with diolefins, alone or together with smaller amounts of other ot-olefins, with the formation of normally solid crosslinkable copolymers.Examples of diolefins that can be used are butadiene, 1,5-hexadiene, dicyclopentadiene and ethylidene norbornene ₀ Particularly preferred polymers are homopolymers Ethylene «Particularly preferred copolymers are the ethylene-propylene or ethylene-butene copolymers which contain up to about 20% by weight of aisohpolymerized propylene or butene

The polymerization should be carried out with care,

to prevent the introduction of moisture and air (oxygen)

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ORIGINAL n * SF £ CTED

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avoid ^ that poison the catalyst,

The ethylene polymers prepared with the aid of the catalyst according to the invention can generally be divided into those polymers with a high molecular weight and high density (0.9A to 0.97) and those with a low density (0.91 to 0.92). However, they differ in the I ₀ R. spectra from the so-called Ziegler and Phillips polymers and represent a new class of polymers, the formation of which is novel with regard to the type of growth of the polymer chains ο The growing polymer chains can be those of the usual linear ones They can be of the type in which the chromium is always bonded to a primary CHp carbon atom, or they can be of the branched type in which the chromium is bonded to a secondary carbon atom through an isomerization reaction that takes place simultaneously with the polymerization.

The properties given in the following examples were determined using the following standard procedures;

Melt Index (MI) ASTM D-1238-62T Melt Flow (MF) ASTM D-1238-62T, at

30.9 kg / cm ² (440 psi) and 190 ⁰ C,

Density ASTM D-I505

example 1

According to the information from Kurras and Klinisch in months ο, Deut echo Akad. D. Wise., Berlin 6, 736 (196 *), a Allylchrom (III) complex prepared by reacting allyl magnesium bromide was reacted at -20 ° C under a slight argon pressure with chromium trichloride _β The excess allyl magnesium bromide was then purified by passing dry, carbon dioxide säuerstoffreiem decomposed into the solution. The inorganic magnesium salts were removed by filtration at -20 ⁰ C, and the ether was distilled off in vacuo at -20 ⁰ C and replaced with dry hexane. The one with it

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ORiGlNAL INSPECTED

196325G - 17 -

"solution containing Allylchroia in about 0.5 molar concentration, was immediately cooled to -78 ⁰ C for storage

Control experiment A

The stock solution prepared above was heated to about 5 ° G and with the help of a syringe, a 0.5 ml sample was taken, the sofoft into a suspension of 400 mg of silica gel, which had been previously activated at 580 ⁰ C, in about 400 ml dry, airless hexane was injected. Then the stock solution was rapidly cooled to -78 ⁰ C and kept at this temperature storage. Once this is applied to a substrate ^ Allylchrom with ethylene at a temperature of 75 to 100 ⁰ C and a pressure of 21.1 kg / cm (300 psi) came into contact, the ethylene in a strongly exothermic reaction was dimerized under formation of butenes, Hexenes, some higher hydrocarbon oils and some traces of polymer with a density of 0.91 and a melt index of 6-50 ₀

Example 2

The stock solution prepared in Example 1 was then allowed to warm to room temperature (about 25 ° C) and allowed to stand for about 20 minutes before a second 0.5 ml sample was taken and placed in a suspension of 400 mg of silica gel, which was previously "had been activated at 35O ° C, injecting in about 100 ml of dry deaerated hexane. The complex was immediately deposited on the substrate and resulted in the formation of a reddish brown sand. The Stammlöeung was immediately stored again at -78 ⁰ C. The catalyst sand was in given a equipped with a stirrer autoclave about 5OO ml bath maintained at about 50 ⁰ O, dry, luftfreiea of hexane. the system Wurd · to a temperature of 72-75 ⁰ O and heated with ethylene under a pressure of 21.1 kg / cm (300 psi) set Et ₁ , the polymerization set in immediately and further ethylene was added in the required amount. After 35 minutes, this was obtained

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126 g of a polymer with a melt flow of 0.1 dg / min, and a density of 0.957 ° The I, H. spectrum of the ethylene polymer differed in the range from 10 to 11.3 microns from the I oll «spectra of the so-called Ziegler resins. The productivity of the catalyst was over 6,000 g of polymer per gram of chromium per hour.

Examples 3-11

Using the stock solution prepared in Example 1, a series of polymerizations were carried out over a period of 2 weeks in which other carriers, comonomers and modifiers were used. In any case, the temperature of the stock solution to ß ° G or was brought up again and then stored at -78 ⁰ C for removal of the catalyst sample. In these polymerization experiments, a maximum productivity value of the catalyst of more than 400,000 g of polymer per gram of chromium per hour was obtained.

As the solution ages (for example in Example 9), a decrease in activity was found and the amount of solution used to prepare the catalyst was increased and in the last tests reached a maximum value of 8 ml ο

The results obtained in these polymerization experiments are summarized in Table I below.

Control experiments B and C

Those in Examples 1 and 2 of U.S. Patent 3,379,705 The data given were compared with the results obtained according to the invention.

In example 11 an ethylene-propylene copolymer was produced. In the other examples, 1-ethylene homopolymers were produced o

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The polymer obtained in Example 3 had a density of 0.955 ° The polymer obtained in Example 4 had a density of Oj ° A5 and a methyl content of 0.2 *% _e. The polymer obtained in Example 5 had a density of 0.933 and a methyl content of 1.14 %. The polymer obtained in Example 10 had a density of 0.950 and a methylene content of 0.16% "The polymer obtained in Example 11 had a density of 0.942 _o In the reactions of Examples 4 to 10 was butene-1 formed as oligomeric byproduct. In the implementation of Example 3, no butene-1 was formed »

It has been shown that the allylchromium applied to a support is both a polymerization catalyst for ethylene % or ethylene / α-olefins and an isomerization catalyst for ethylene. The isomerizing effect increases as the activation temperature of the carrier increases. At an activation temperature below 400 ⁰ C, the polymerizing effect predominates at an activation temperature above 500 ° C the isomerizing activity is important; the range from 400 to 500 ° C is the transition area »With the help of the allyl chromium applied to a carrier, it is not only possible to polymerize ethylene to a homopolymer with a high molecular weight, but also to oligomerize ethylene to olefins with a relatively low molecular weight. The oligomerization effect decreases also with increasing activation temperature of the support and with increasing ä the polymerization zuο the pressure applied to a carrier Allylchrom catalyst of the invention is an effective Ätnylen-a-olefin Mischpolymerisationskatalysator, by means of which it is possible, at polymerization temperatures below about 100 ° C copolymers with Density in the middle density range (0.94), when polymerizing in solution (higher temperatures) to produce copolymers with low density (0.91 to 0.92). Alternatively, the polyethylene may be labeled "low-density" in low yield even after the ^H particle form "process are established when the Aktivierungetemperatur of the carrier at about 58o ⁰ G liegte

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ο-co to

cn to CD

> ■■ ·
r

-Xi

Table I Polymerization Data

Polymerization conditions

Wr. catalyst Carrier* Tempo ( ⁰ C) kg / cm * - (psi) ^C 3 ^H 6 % 8th (in moles; 21.1 (300) Ix) kp / cm (i> si) ro
O 3 <o, 7 MSID-SiO ₂ 75-80 21.1 (300) 0 I. 4th < 0.7 ti 88-94- 19.3 (275) - 0 5 <0.6 It 75-126 19.0 (270) «Approx 1.76 (25) 6th <0 ₉ 2 It 86-90 19.3 (275) .. » 2.11 (30) 7th 4.0.3 ID-SiO ₂ 84-92 17.6 (25Ο) 1.76 (25) 8th <0.6 It 86-90 21.1 (300) - 3.52 (50) 9 <0.7 MSID-SiO ₂ 83-94 14.1 (200) - 0 10 <1.4 It 90-94 21.1 (300) 7.03 (100) 11th <1.9 ID-SiO ₂ 88-90 10 0

Control ▼ request B 3.4

Control test C 3.4

738
735

0 0

cn ca ro cn ο

Tortsetsung τοη Table I.

O
Ω "_ .. _,, conditions of polymerisation Time yield
(Min.) (G) 126 productivity
(g / g Cr / hour) Properties of the MF Br. C ₅ H ₆
'% Polym. 30th 134 50,000 Polymer 0.10 L! NSPECTED 3 28 26th 53,000 MI 0.7 4th 23 86 - KP ** 91 5 36 106 400,000 KP 1.8 6th 25th 62 > 22,000 0.6 2.4 O 7th 20th 92 > 6,000 0.01 3.6 O
to 8th 20th 133 > 7 600 0.02 1.0 00 9 30th 37 > 3 700 0.01 7.2 co 10 90 7 250 KP 7.1 . * 11 3 Λ 5 0.10 «71
10 300 32 5 0.03 KP m Control
attempt B - 300 36 - Control
attempt C - at 35O ° C * activated in argon - ** HP » no river

cn co ro cn ο

Claims (1)

196325C I, polymerization catalyst, characterized in that it consists of a T-allylchromium (III) complex applied to a carrier with a large surface area, which is at least is partially reduced to a TT-allylchrome (II) complex ο 2 ο catalyst according to claim 1, characterized in that practically all of the chromium in the T-allylchromium complex is in a bivalent state « 3 ο Process for the production of the allyl chromium polymerization catalyst according to claims 1 and 2, characterized in that at least part of a T "allyl chromium (III) complex reduced to a T-allylchromium (II) complex and the reduced allylchromium complex is deposited on a carrier with a large surface ο 4ο The method according to claim 3 »characterized in that the ir-allylchrome (IXX ^{) complex is reduced at a temperature above -17 0} O to the T-allylchrome (II) complexo 5 * Process according to claim 4, characterized in that practically all of the chromium of the T-allylchromium (III) complex is converted into the divalent state «, 6. Use of the polymerization catalyst according to claims 1 and 2 for the polymerization of 2 or more ethylene * · units, either alone or with others with it copolymerizable monomers »characterized in that a T-allylchron complex is used as a catalyst, the was deposited on a carrier with a large surface and the chromium content of which is at least partially in a bivalent state < > 7 · Use according to claim 6, characterized in that • is used in a catalytic converter in which practically the entire · 009829/1698 ORiGlM fNSPECTED - 23 Chromium is in a bivalent state ο 8 ο Use according to claim 6 or 7 »characterized in that the polymerization in the presence of hydrogen
is carried out c 9 ο Use of the polymerization catalyst according to claims i and 2 for the oligomerization of ethylene, in which the ethylene is at a temperature of about 30 to about 200 ⁰ O and
a pressure of about 2.41 to about 57 _sec 2 kg / cm (20 to 800
psig) is brought into contact with a catalytic amount of the T-allylchromium (III) complex applied to a support ο 009829/1598