CS259736B1 - Catalyst for 1-alkenes polymerization and copolymerization - Google Patents

Abstract

The solution relates to a catalyst for the polymerization and copolymerization of 1-alkenes. On a porous silicon oxide and/or aluminum oxide containing 0.3 to 3 mmol/g of surface OH groups, at least one aluminum compound of the general formula (I) is applied, then at least one titanium compound of the general formula (II) and finally at least one magnesium compound of the general formula (III), where R1, R2, R3, R4, R5 are alkyls with 1 to 10 C atoms or aryls, wherein R2 and/or R3 can also be halogen, hydrogen or alkoxide OR1, k is 1 to 3, 1, m, r, s is 0 to 2, wherein k + l + m = 3, r-(~ -j- s = 2, X, Y are halides, and alkoxides with R1, cyclopentadienyls, wherein Xz can be oxygen, p, q are 0 to 4, wherein p -j- -|- q = 3 or 4 in molar ratios 1/ /OH of the carrier 0.1 to 10, II/I to 100, III/II 0.5 to 20. AlR^R^Rm3 (I) TiXpYQ (Π) MgRr4Rs& (III)

Description

The invention relates to supported catalysts for the polymerization and copolymerization of 1-alkenes, in which oxides are used as a support. Contemporary catalytic systems for the polymerization of 1-alkenes have already achieved considerable perfection. In particular, the introduction of supported catalysts, which increasingly use catalytically active metal, allows for the achievement of relatively high activities - more than 3,000 kilograms of polymer/g of catalytic metal. MPa . h. Catalytic systems based on transition metals are widely used, which, in addition to high activities, also exhibit good copolymerization parameters. These are compounds of the general formula:

M _m M*X _2ni Y. nE where

M = Mg, Mn, Ca

M' = Ti, V, Zr

X = Cl, Br, J

Y = halogen, —OR, —SR, —NRz, where R is alkyl, m = 0.5 to 2 n = 0.25 to 40

E = electron donor (ether, alcohol, ester]

Catalyst activation is carried out directly in the polymerization reactor, most often with organoaluminum compounds. Catalysts of this type are described, for example, by Karol in US 4,302,566, Stevens in US 3,787,384, Strobel in US 4,148,754, Ziegler in US 4,063,009 and Graft in US 4,173,547. Other supported catalyst systems based on titanium compounds are described in patents GB 1,484-254, DT 2,809-272, BE 884-513, GB 2,099-834 and US 4,490-514. A common feature of these systems is the interaction of an inorganic support with an organomagnesium and/or organoaluminum compound with subsequent interaction with a transition metal compound. Activation with an organoaluminum component is carried out immediately before the polymerization itself or in the reactor, which forces the dosing of a large amount of organometallic compounds into the reactor, leads to more complex control of the polymerization process and can lead to more frequent formation of lumps in the reactor.

Especially in the case of gas phase polymerization of 1-alkenes using catalysts based on transition metals IV. and V. and a group of the periodic table of elements, the dosing of an organoaluminum compound into the reactor is a source of unpleasant technological problems. Due to the influence of traces of oxygen and moisture, the walls of the reactor and other equipment are coated with aluminum oxide, which is a strong adsorbent of impurities that deactivate the catalysts. These are removed again by reaction with organoaluminum compounds, which further worsens the problem. A method for preparing single-phase, multicomponent catalysts that do not require activation by an organometal in the reactor and do not have the aforementioned negative properties was described in AO No. 256 961.

Some patents describe the preparation of supported catalysts based on titanium compounds, whereby the silica surface is first treated with phosphorus compounds (US 4,510-299), inorganic sulfur compounds (J5 2,000-880) or an organic silicon compound (DE 3,228-065), after which the thus treated support (largely free of reactive hydroxyl groups) is first reacted with an organometallic compound and then with transition metal compounds. Some patents (BE 866-957, DT

721—194, DE 3,404—668, BE 845—983, BE 857—100, US 4,446—288, BE 846—450, DE

228—065) describe the application of the reaction products of organometallic compounds with polar and non-polar solvents (alcohols, ethers, esters) to a support, thereby changing the surface layer of the support, without these reaction products forming an active part of the polymerization center with the ability to alkylate and reduce the transition metal compound.

Patents BE 866-420 and J5 4 138-887 describe the preparation of an unsupported catalyst for solution polymerization. Although they produce a single-phase catalyst, it is not suitable for gas phase polymerization because it does not have a suitable particle distribution.

The shortcomings of the mentioned carrier catalysts are eliminated by the catalyst according to the invention.

The subject of the invention is a catalyst for the polymerization and copolymerization of 1-alkenes, which can be prepared by applying at least one compound of the general formula to a support formed of silicon and/or aluminum oxides with a particle size of 1 to 1,000 μΐη, a pore volume of 0.3 to 3 cm ³ /g, a surface area of 100 to 1,000 m ² /g containing 0.3 to 3.0 mmol/g of surface OH groups, in a hydrocarbon solvent environment or in the vapor phase at a temperature between the freezing point and the boiling point of the substances used.

AlR _k ¹ R1 ² Rm ³ (I) then at least one titanium compound of the general formula II

TiXpY, (II) and finally at least one magnesium compound of the general formula (III)

MgR/R/ (III) where R ¹ , R ² , R ³ , R ⁴ , R ⁵ are alkyls with 1 to 10 carbon atoms or aryls, wherein R ² and/or R ³ can also be halogen, hydrogen or alkoxide OR ¹ , k is 1 to 3,

1, m, r, s is 0 to 2,

259738 where k + l + m = 3 and r + s = 2,

X, Y are halides, alkoxides, cyclopentadienyls, where X2 can be oxygen, p, q are 0 to 4, where p + q = 3 or 4, in molar ratios J/OH of the carrier of 0.1 to 10, II/I of 1 to 100, III/ΊΙ of 0.5 to 20.

The support for the preparation of the catalyst according to the invention is silica or silica/alumina, which is dehydrated at temperatures of 200 to 900 °C with a stream of air and/or nitrogen in a fluidized bed for at least 4 hours. The silica thus treated contains, depending on the dehydration temperature, 0.5 to 3 mmoles of OH groups per 1 g.

The preparation of the supported catalyst according to the invention can be divided into several stages:

1. Interaction of the reactive sites of the support with one or several organoaluminum compounds in succession. Reaction products are formed, firmly fixed on the surface of the support. The molar ratio of the sum of organometals I to the OH groups of the support is in the range of 0.1 to 10, preferably 0.5 to 1.0.

2. Interaction of the carrier prepared according to point 1 with one or more compounds II. The titanium compounds are firmly anchored on the carrier and its reaction with the fixed reaction products from point 1 occurs. The molar ratio of the sum of organoaluminum compounds I to the sum of compounds II is maintained in the range of 1 to 100, preferably 5 to 20.

3. Interaction of the support prepared sequentially according to points 1. and 2. with one or more organomagnesium compounds III. The molar ratio III/II is maintained in the range of 0.5 to 20, preferably 1 to 8. The organomagnesium compound is anchored in the surface layer of the support particles, its diffusion into the interior of the particles does not occur during, preparation and storage of the catalyst. This accumulation of the organomagnesium compound on the outer surface of the support particles has a beneficial effect on the stability of the active center against the possible deactivating effect of strong electron donor compounds, which are usually contained in traces in the raw materials or may come into contact with the catalyst during its preparation, storage and transport.

The above operations are carried out in a hydrocarbon suspension in the temperature range determined by the freezing point and boiling point of the hydrocarbon used, preferably at temperatures in the range of 20 to 40 °C, or depending on the physical properties of the components used, also by direct contact of the vapors of the respective component with the carrier. The presence of electron-donor solvents such as alcohols, ethers, esters in more than trace amounts is undesirable.

The gradual interaction of the individual components of the catalytic system according to points 1 to 3 creates an active polymerization center with optimal ability to polymerize 1-alkenes. Fixing the components on the support prevents their migration and thus also prevents unwanted side reactions leading to the disappearance of the active centers.

The catalysts prepared according to the invention have, in comparison with previously known catalysts, a number of advantages: they maintain high activity even after a long storage period, they provide excellent granulometric composition of the product and high bulk density, and their use does not result in the formation of aluminum oxide deposits on the inner walls of the polymerization reactor. By appropriate selection of components and conditions for catalyst preparation, it is possible to easily control the polymerization kinetics (so that even at high speeds there is no formation of remelted lumps), the average molecular weight, the molecular weight distribution and the morphology of the polymer particles within a wide range.

The invention will be illustrated by the following examples. The ratios given in the examples are molar.

Example 1

General procedure for catalyst preparation

A dried glass reactor with a volume of 100 ml is charged with 50 ml of a hydrocarbon (e.g. heptane), freed from water and oxygen, 5 g of a carrier activated for 4 h in a nitrogen stream at a temperature of 200 to 900 °C, a solution of an organic aluminum compound of the general formula I or a mixture thereof in a hydrocarbon are added and the mixture is stirred at room temperature for 10 minutes. Then one or more titanium compounds of the general formula II are added (preferably in the form of a hydrocarbon solution) and left to react with stirring for 30 minutes at room temperature. Finally, a solution of an organic magnesium compound of the general formula ΙΓΙ or a mixture thereof in a hydrocarbon is added. After 30 minutes, the product is freed from the solvent (e.g. by evacuation). The resulting beige powder can be used as a catalyst for polymerization in a fluidized bed reactor.

Example 2

A 1-liter glass reaction vessel is equipped with a spiral stirrer that allows for perfect, intensive mixing of bulk materials. 300 g of carrier activated for 4 hours in a N2 stream at a temperature of 200 to 900 °C is poured into the nitrogen-dried vessel and the stirring is turned on. Ultrapure nitrogen is introduced through a glass frit to the bottom of an 80 ml evaporation vessel and bubbled through a solution of organoaluminum component I or their mixture in a hydrocarbon (e.g. hexane) and, after saturation with vapors of the organoaluminum component, is introduced through the bottom of the reaction vessel into the layer of the activated support. After evaporation of the solution of organoaluminum compounds, titanium compound II or their mixture (preferably in a hydrocarbon) is added to the evaporation vessel and introduced into the reaction vessel in the same way. Finally, an appropriate amount of organomagnesium compound III or its mixture is added to the evaporation vessel and allowed to evaporate with a stream of nitrogen until the evaporation vessel is completely dry. The evaporation of compounds I—III can be significantly accelerated by heating the evaporation vessel. The individual reaction components I—III can be added to the evaporation vessel pure or as solutions in hydrocarbons. During the preparation of the catalyst, the reaction vessel is maintained by external cooling at laboratory temperature, a slight increase in temperature by the heat of reaction to 60 to 80 °C is not a problem. A free-flowing white to beige powder is obtained, which can be directly used for polymerization in a fluidized bed reactor.

All manipulations with the activated carrier and substances I—III must be performed in an ultra-clean environment, preferably under a flow of ultra-pure inert gas (nitrogen, argon) with a content of < 1 ppm H2O and < 1 ppm O2.

Example 3

The catalysts were tested by polymerization of 1-alkenes in a laboratory 1.5 l batch fluidized bed reactor, which allows the preparation of 250 g of polymer and/or in a pilot-scale continuous fluidized bed reactor with a productivity of 25 kg polymer/h. The different catalyst compositions and polymerization test conditions are listed in Tables 1 and 2.

239736

Table 1:

Examples of catalytic systems for the polymerization of 1-alkenes

Pore. No. Catalogs- I I1/I2 I/OH II II1/II2 I/II III ΙΙΙ1/ΙΠ2 — III/II zator OH in

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Table 2:

Tests of polymerizations of 1-alkenes on the catalyst according to the invention

Catalyst Partial pressures MPa H2 Temperature ethylene propylene 1-butene °C

Time Yield of polymer

1 18 _ _ 2 90 _ 15* 1 17 — 1 2 90 — 13* 2 18 — — 2 90 2 240 3 16 — — 4 90 2 140 4 16 — 2 2 80 3 230 5 16 4 — . — 80 3 180 6 16 — 2 2 90 2 260 7 18 — — 2 100 2 200 8 16 — 2 2 90 2 240 9 18 — — 2 100 2 230 10 16 2 — 2 80 3 280 11 18 — — 2 80 2 40 12 18 — — 2 80 2 30 13 — 18 — 2 80 4 20 14 — 2 16 2 80 4 8 15 18 — — 2 100 2 25

Note:

The catalyst charge in the laboratory reactor was always 0.1 g. * — productivity data in kg/h, obtained from the pilot plant unit píedmEt

Claims (1)

Catalyst for the polymerization and copolymerization of 1-alkenes prepared by contacting a support of silicon and / or aluminum oxides with a particle size of 1 to 10,00 gm with a pore volume of 0,3 to 3 cm ³ / g, with a surface area of 100 to 1 000 m ² / g, containing 0.3 to 3.0 mmol / g of surface OH groups, is applied in the environment of a hydrocarbon solvent or in the vapor phase at a temperature between the freezing point and the boiling point of the deposited substances at least one aluminum compound of the formula AlR _k ¹ R, ² R _m ³ (I) then at least one titanium compound of formula II TiX _p Y _q (Π) Invention and finally at least one magnesium compound MgR of formula III, R ^4? (III) wherein R ¹ , R ² , R ³ , R ⁴ , R ⁵ are alkyl of 1 to 10 carbon atoms or aryl, wherein R ² and / or R ³ may also be halogen, hydrogen or an alkoxide OR ¹ , k is 1 to 3 1, m, r, s is 0 to 2, with k - | -1 m = 3 and r + s = 2, X, Y are halides, alkoxides with R ¹ , cyclopentadienyl, wherein X 2 may be oxygen, p, q are 0 to 4, wherein pq = 3 or 4, in molar ratios I / OH of carrier 0.1 to 10, II / I to 100, III / II 0.5 to 20.