Methods for the polymerization of alpha-olefins

Abstract

A process for polymerizing a -olefins comprises (a) treating a solid catalyst carrier with chromyl chloride, activating the catalyst system obtained by heating it in the presence of an inert gas or an oxygen-containing gas; and (b) contacting the activated catalyst system with an a -olefin in the presence of an organic liquid solvent or diluent. Specified olefins are ethylene, propylene, isobutene, pentene-1, hexene-1, butadiene and isoprene. Specified solvents and diluents are propane, butane, isobutane, n-pentane, iso-pentane, n-heptane, iso-octane and cyclohexane. Specified carriers are silica, alumina and silica / alumina. Examples describe the polymerization of ethylene in (1)-(3) cyclohexane; (6), (9) and (11) n-heptane; and (12) isooctane; of propylene in (4) n-heptane and hexene-1 in (5) n-heptane using catalysts formed from chromyl chloride and silica / alumina; and the polymerization of ethylene in n-heptane in the presence of catalysts formed from (7) chromyl chloride and alumina; (8) chromyl chloride and silica; and (10) chromyl chloride, chromyl fluoride and silica / alumina.

Description

The invention relates to a process for the polymerization of OC olefins in the presence of organic solvents at temperatures below 210°C and pressures below 200 atm using a supported catalyst. This catalyst is produced by impregnating the support materials. Silicon dioxide, aluminum oxide or silicon dioxide-aluminum oxide with chromium salts and activation by heating in the presence of inert or oxygen-containing gases, as well as oxygen itself. The method of the invention is characterized in that the catalyst is activated by treating the support material with Chromyl chloride was obtained alone or in mixture with chromyl fluoride. For activation, the catalyst is preferably heated to temperatures between 1500 and 8000°C, primarily between 909883 / 1582 500° and ΔΔΔ° C. The best results are obtained with the polymerization process when the catalyst is heated for a time of 1 The activation period is up to 8 hours. Satisfactory results are achieved with an activation duration of less than 24 hours. Solvents or diluents are used to carry out the polymerization, which are suitable for the monomer and the polymer formed. are inert and also dissolve the polymer. Suitable solvents are aliphatic and cycloaliphatic hydrocarbons such as propane, butane, Isobutane, n-pentane, isopentane, n-heptane, isooctane, cyclohexane and the like. The process is carried out at pressures sufficient to ensure that the solvent or diluent used is at the predetermined levels. Temperature conditions for keeping the polymerization liquid and dissolving the oC olefins in the solvent or diluent in quantities that sufficient for a satisfactory polymerization process. After completion of the polymerization, the catalyst is separated from the polymer and destroyed by heating in the presence of oxygen or air. It is reactivated. In this process, the polymer is freed from the solvent. The use of the catalyst treated according to the invention leads to very high yields of polymer of a 909883 / 1582 high degree of crystallinity, such as could previously only be obtained by using supported catalysts that had previously also contained chromium oxides contained substances that had not been treated with the aforementioned chromyl halides prior to their activation. This has been established in experiments. In these experiments, the method according to the invention was compared with methods according to the known prior art. (Belgian patents 5^0 617 and 555 O82) compared, in which the catalysts produced in the respective different ways described were used. The production of the various catalysts is described below: Catalyst A (according to the invention) A mixture of nitrogen and pure chromyl chloride was passed through a fluidized bed of silicon dioxide and aluminum oxide (type) at room temperature. HPV (microspherical) from the company Ketjen, which contained 87% silicon dioxide and 1% aluminum oxide, was used. The catalyst was used for activation. activated for two hours at 51K)0C under an oxygen stream that kept the catalyst in a fluidized bed state. Catalyst B (according to the state of the art) The same carrier was used as in the manufacture of the 909883 / 1582 Catalyst A was used. The support was treated with an aqueous solution of CrO₂ and then dried under vacuum at HO₂C for several hours. For activation, the catalyst was heated for two hours under a stream of oxygen, which kept the catalyst in a fluidized bed state. Using catalysts A and B, ethylene was polymerized under otherwise identical conditions. The experimental conditions and results are summarized in the following table. The invention is explained by the following examples. Example 1 0.9 g of chromyl chloride were placed in a reaction vessel equipped with a wash bottle and an upper outlet tube. The wash bottle was connected to a nitrogen source, while the upper outlet tube was connected to a second reaction vessel containing 10 g of silicon dioxide-aluminum oxide with 87% silicon dioxide and 15% aluminum oxide, in which the fluidized bed method could be used. When nitrogen was blown into the chromyl chloride, its vapors were... - 5 909883 / 1582 Ver Kataly Dhrome content Polymeri Catalyst- Tempe Pressure Ver Produk Producti such sator Im Gesarnt- 6-valent station ions - conzentra ratur because tivity vity for Leatalysant Chromium In solution ion in solution time for the metal Jesamtkata- mittel smittel Jesamt - sches Chrom lysator kataly sator No. Gew.-# Gew.-% g / l 0C atm Std. g / g / h+ g / g / h++ 1 A 2,97 2,46 n-Heptane 0,15 I50 40 1 108 3630 2 A &eegr; Il Il Il Il tt It 118 3970 O 3 A If It If tt It tt ft 108 3630 CO A ti It Il If ti ti It 127 4270 co 5 A &eegr; The It tt tt ti tt 128 5240 -. 6 A It Il It It ti tt tf 122 5000 w 7 A It It It It It It It tf 157 6430 ' co 8 B 2.75 2.36 It ti It tf ti 62 2250 ^ 9 B It Il ti Il tt ti Il 58 2110 10 B ti ti It It tt tt ti 60 218O 11 B 2.31 2.07 Il Il Il It It 53 229O 12 B It ti tt If It ti It 50 216O 13 B Il Il &eegr; It tt It Il 47 2030 14 B It tt tt It If tf n 53 229O 15 B 2.30 2.01 tt Il It ti ti 52 226O 16 B It It ti ti It tt tt 51 2210 17 B ti It ti It tt tt It 53 23OO + g polymer / g total catalyst / hour ++ g polymer / g metallic chromium in catalyst / hour on the silicon dioxide-aluminum oxide, which was kept at 150°C. After applying all the chromyl chloride to the More nitrogen was introduced into the silicon dioxide-aluminum oxide mixture, while the temperature of the silicon dioxide-aluminum oxide mixture was increased to 5200°C and where he was held for two hours. After cooling, the catalyst thus obtained was used with good results in the polymerization of ethylene to a solid product in the following manner. Method used: 2.8 g of catalyst were suspended in 250 ml of cyclohexane, and the suspension was placed in a 500 ml autoclave and submerged. heated to 140°C at an ethylene pressure of 36 atm. After two hours, the introduction of ethylene was stopped, the autoclave was cooled and emptied. After removing the catalyst and the The weight of the polyethylene obtained was determined to be 59 g using the solvent. Example 2 1.8 g of chromyl chloride and 20 g of silicon dioxide-aluminum oxide were placed in a device according to Example 1. The chromyl chloride was deposited on the silicon dioxide-aluminum oxide using the same method as in Example 1, except that oxygen was used instead of nitrogen. was used. - 7 -909883 / 1582 After all the chromyl chloride had been deposited on the silicon dioxide-aluminum oxide, oxygen was introduced for a further 20 hours. whereupon the catalyst was activated for two hours at 5100°C in a stream of dry air. 1.8 g of the catalyst thus obtained were placed in a 500 ml autoclave containing 250 ml of cyclohexane. The mixture was then incinerated for two hours at Polymerization was achieved at 140°C and 55 atm ethylene in this autoclave. 57 g of solid white polyethylene with high crystallinity were obtained. Example 3 The catalyst was prepared as follows: 5 g of chromyl chloride were placed in a glass vessel equipped with a gas inlet tube and It was equipped with a gas outlet pipe. A stream of inert gas was passed through the gas inlet pipe; the mixture of inert gas- Chromyl chloride vapors were fed through the outlet pipe into a reaction vessel containing silicon dioxide and aluminum oxide. After approximately one The gas supply is interrupted after one hour and the catalyst is heated to approximately 5000°C for two hours in a dry air stream. activated. 2.7 S of the catalyst thus obtained were placed together with 250 ml of cyclohexane in an autoclave; this 909883 / 1582 The container was closed and heated to 140°C. Within two hours, ethylene was then extracted under an average pressure of 40 atm. initiated. The autoclave was then opened and the reaction product was separated from the solvent and catalyst. 60 g of solid, white material was obtained. Polyethylene obtained. Example 4 The catalyst was prepared as in Example 1 and contained 5.27% chromium. 8.4 g of this catalyst were heated at 52°C for 2 hours in a activated by a stream of dry air and then cooled in a nitrogen stream; subsequently, it was placed together with 200 ml of n-heptane in a 500 ml- The autoclave was fitted with a stirrer and had previously been washed and evacuated with nitrogen. The autoclave was then closed, heated to 95°C and held at that temperature for two hours, while propylene was introduced at 55 atm. was. After 2 hours, the autoclave was opened and cooled. Besides the solvent and catalyst, 22.4 g of oily-looking material were removed. Polypropylene was obtained from the autoclave. The polymer thus obtained was extracted with n-pentane, in which it was heated under reflux for 20 hours. 909883 / 1582 In this way, 18 g of a viscous liquid fraction was obtained that was soluble in pentane. The residue from the pentane extraction was extracted with n-heptane for 20 hours under boiling and reflux; 2.50 g of a solid, obtained a waxy fraction that was soluble in n-heptane. The fraction insoluble in boiling n-heptane was separated from the exhausted catalyst by extraction with boiling xylene, yielding 1.9 β solid crystalline polypropylene was obtained. Example 5 The catalyst was produced according to example !; it contained 1.6l % chromium. 9 g of this catalyst were activated for 2 hours at 5000°C in a dry air stream; then they were cooled in a nitrogen stream. 150 ecm of n-heptane, in which the activated catalyst had previously been suspended, was added to a 500 ml autoclave equipped with a stirrer and hot oil circuit. was applied, and 150 ecm 1-hexes were added. The autoclave was then closed, cleaned with nitrogen, and heated to 1200°C. After 2 hours The heating process was stopped, the autoclave was cooled down and then opened. - 10 909883 / 1582 Besides the exhausted catalyst, the solvent and the unreacted 1-hexene, 14 g of polymeric, oily-looking 1- Witches extracted. Example 6 1.4 g of chromyl chloride were placed in a glass container equipped with a wash bottle; the container was then covered with a reaction vessel. connected, which was suitable for the fluidized bed process and contained 21 g of S11icium dioxide aluminum oxide (Davison) with 87% S11icium dioxide, which had previously been dried for 2 hours at 40°C. The chromyl chloride was then applied in gaseous form to the surface using a stream of dry air. blown silicon dioxide-aluminum oxide. After the introduction of chromyl chloride into the silicon dioxide-aluminum oxide-containing reaction vessel was completed, this was left for half a day. Heated to 3000°C for one hour in a dry air stream; then, still in the dry air stream, the temperature was increased to 5000°C and 2 The system was held at this altitude for several hours, after which it was cooled in a dry nitrogen stream. 8.5 g of the catalyst thus produced (containing 2.02% chromium) were placed in a 21-room autoclave with a stirrer together with 150 ecm n-heptane. given. «. 11 “ 909883 / 1582 The autoclave was then heated to 160°C, during which ethylene was introduced at a pressure of approximately 40 atm. After 1 hour, the introduction of ethylene was stopped. aborted, the autoclave opened and cooled down. 326 g of solid white polyethylene were obtained. Example 7 The catalyst was produced in a similar apparatus to that described in Example 6. 1.4 g were introduced using a dry air stream. Chromyl chloride was transferred at room temperature to 2 oz of aluminum oxide (Ketjen), which had previously been dried for 2 hours at 50°C. The... The reactor containing aluminium oxide was then exposed to a dry air stream for half an hour at JOO0C and then for another 2 hours still at that temperature. dry airflow heated to 500°C. Cooling took place in a stream of dry nitrogen. The catalyst produced in this way contained 2.14% chromium. A suspension of 8 g of the catalyst in 150 ecm n-heptane was placed in a 21-cell stainless steel autoclave equipped with a stirrer and stuffing box. The autoclave was then heated to 140°C for 1 hour, during which ethylene was introduced at a pressure of 40 atm. - 12 - 909883 / 1582 After the reaction was complete, the autoclave contained 32 g of solid, highly crystalline polyethylene. Example 8 The catalyst was prepared by passing 0.9 g of CrOpCl₂ over 15 g of Ketjen silicon dioxide, which had previously been dried for 1 hour at 5500°C; the apparatus and method of preparation for the catalyst were the same as in Example 6. The catalyst thus prepared contained 1.58% chromium. In the autoclave described in Example 7, the polymerization of ethylene was carried out for 1 hour at 140°C and 40 atm, using 8.3 g of the previously described catalyst suspended in 150 ecm n-heptane. 200 g of solid white polyethylene were obtained. Example 9 The catalyst containing 2.5% by weight of chromium was prepared as in Example 1 and then activated in a dry nitrogen stream for 2 hours at 3500°C and subsequently cooled in a nitrogen stream. - 13 909883 / 1582 47 g of the catalyst suspended in 250 ml n-heptane were placed in a 1000 ml autoclave in which ethylene was heated at 140°C under a pressure It was polymerized at 40 atm. After 1 hour, 472 g of solid, white polyethylene with high crystallinity were obtained. Example 10 2 g of chromyl chloride were placed in a Monel metal wash bottle through which a gaseous mixture containing 90% nitrogen was passed. and contained 10% hydrogen fluoride; the flow rate was 500 ml / minute. The gaseous mixture that flows out of the wash bottle consists of chromyl chloride, chromyl fluoride, chromyl chlorofluoride, The reaction, consisting of hydrogen chloride, hydrogen fluoride, and nitrogen, was carried out at room temperature through a stainless steel reaction vessel. directed, which contained 100 g of silicon dioxide-aluminum oxide (Davison) with 87% silicon dioxide. As sioh no chromyl hydroxide In the When the wash bottle was located, the hydrogen fluoride flow was interrupted while nitrogen continued to be introduced to stimulate the catalyst. to clean away any acid fumes. The resulting catalyst contained 1.37% chromium. - 14 -909883 / 1582 12.5 g of this catalyst, activated for 4 hours at 50°C in a dry air stream and cooled in a nitrogen stream, were dissolved in 250 ml n-Heptane was suspended. The suspension was placed in a 1000 ml autoclave into which ethylene was introduced at 140°C and 40 atm pressure. After 1 hour, 243 g of solid, white polyethylene of high crystallinity were obtained. Example 11 A catalyst prepared according to Example 1 and containing 3.27% chromium was heated for 2 1 / 2 hours at 400°C in a dry air stream. activated and cooled in a nitrogen stream. 9.4 g of the catalyst thus prepared were suspended in 200 ml of n-heptane and placed in a container with The autoclave, equipped with a stirrer and previously purged with nitrogen, was placed in the autoclave. The autoclave was then heated to 140°C while ethylene The process was introduced at a pressure of 40 atm. The ethylene was maintained at a temperature of 140°C and a pressure of 40 atm for 1 hour. The unreacted ethylene was then removed and the autoclave cooled. 260 g of solid, white, highly crystalline polyethylene were obtained. - 15 909883 / 1582 Example 12 9.5 g of a catalyst prepared according to Example 1 containing 1.6% chromium by weight were activated for 2 hours in dry air at 5000°C was placed in an autoclave containing 200 ml of isooctane. The autoclave was then closed and heated to 140°C, while simultaneously Ethylene was introduced at a pressure of 55 atm. After 1 hour, the autoclave was opened and cooled. 410 g of polyethylene were obtained. - 16 909883 / 1582

Claims

- 16 patent claims 1. Process for the polymerization of oC olefins in the presence of organic solvents at temperatures below 210°C and pressures below 200 atm. using a catalyst, produced by impregnating the carrier materials silicon dioxide, aluminum oxide or silicon dioxide- Aluminium oxide with chromium salts and activation by heating in the presence of inert or oxygen-containing gases, as well as oxygen itself, characterized in that the catalyst is activated by treating the support material with chromyl chloride alone or in a mixture was obtained with chromyl fluoride.

2. The method according to claim 1, characterized in that the catalyst is heated to temperatures between 150° and 8000°C, preferably activated between 300° and 600°C, in the presence of inert gases, oxygen or oxygen-containing gases. (Art.7§1Para.2No.1 909883 / 1582