SE187328C1 - - Google Patents

Description

Inventors: G Natta, G Mazzanti and P Longi Priority requested Iran on 15 July 1955 (Holten) The preparation of suitable catalysts for the formation of linear high molecular weight polymers with regular structure from α-olefins by reacting titanium halides with aluminum alkyl compounds or with aluminum alloys, in particular magnesium alloys, have already been described.

However, the use of aluminum alkyl compounds in practice entails certain responsibilities, since these compounds are very easily oxidized, so that they ignite, and both in test laboratories and in test plants, in which aluminum alkyl compounds are used for the production of such catalysts, many accidents have already occurred. By reducing the titanium halides with aluminum-magnesium alloys, the use of the dangerous aluminum alkyl compounds can be avoided. A disadvantage, however, is that the polymers formed are hardly crystalline. No small amounts of unreacted titanium tetrachloride remain after the reaction, oily liquid polymers are formed, similar to those obtained with Friedel-Grafts catalysts.

It has been found that suitable catalysts for the preparation of crystalline polymers from α-olefins are obtained by reacting titanium alloys, in particular aluminum-titanium alloys, with compounds of the general formula RX, where X represents halogen and R represents an alkyl or aralkyl radical. It is possible to react organic halides with aluminum-titanium alloys and to obtain reactive compounds of a precisely defined structure (in which aluminum and titanium are likely to be bonded to carbon atoms), which can be used as catalysts in the polymerization of α-olefins to substantially linear high molecular weight polymeric polymers. with regular structure.

Dupl. at 39 c: 25/01 This is surprising in all respects, since there has previously been an edge that metallic titanium can react with alkyl halides or with the aluminum halides or aluminum alkyl halides formed by the reaction of aluminum (the strongest electropositive element in the alloys used). ) with the alkyl halides. Nor could it be predicted that organic titanium compounds would be formed under the reaction conditions used according to the invention. As before, edge compounds of such compounds, even at high temperatures, were extremely unstable, as evidenced by the publications of Hermann and Nelson (J. Amer. Chem. Soc. 74 (1952) 2693 and 75 (1953) 3877, 3882) concerning titanium trihalide monoalkyl compounds and titanium trialcoholate monoalkyl compounds which, according to a general process for the preparation of metal alkyl compounds, are prepared by reacting titanium tetrahalides or tetraalcoholates with Grignard compounds or lithium aryl compounds at very low temperatures. By observing that it is possible to react the titanium-containing aluminum titanium alloy with alkyl halides, it has been found that the process of the invention according to which catalysts for the olefin polymerization are prepared by oxidizing titanium so that the 10 alloys used in the titanium derivatives in which the metal exhibits higher valencies (the metal stage element is considered to have zero valence), while titanium compounds in the prior art processes for producing such catalysts are reduced.

Belgian Pat. No. 538,782 describes catalysts which are prepared from titanium tetrachloride and magnesium-aluminum alloys. From these catalysts, the catalysts prepared according to the invention differ further in that in the polymerization they give products which are richer in crystalline polymers.

The reaction according to the invention between alloy and alkyl halide proceeds more easily, if the alloy is very finely divided and thereby has a large surface area. The surface of the alloy must also be as oxide-free as possible. Alloys in the fine state are therefore used as alloys which have been formed, for example, by mechanical grinding in an oxygen-free atmosphere or by injecting small alloys into an inert gas atmosphere. According to the invention, mechanically ground alloys are used in particular, the alloy preferably being reacted with the alkyl halide during the milling in a mill, from which all oxygen has been removed in advance.

Alloys are used, in which the ratio between titanium atoms and aluminum atoms, i.e. the ratio Ti: Al varies between 1: 1.2 and 1: 9.

The best results have been obtained with alloys in which the ratio Ti: Al has been 1: 3. Bromides and chlorides have been used in particular as alkyl halides. Under otherwise similar conditions in the process, the best results have been obtained with the use of chlorides, in particular ethyl chloride. The resulting products contained aluminum and titanium compounds, which are sand-divided by water to form fed-fed carbonates. The polymerization of α-olefins with these catalysts proceeds practically as the polymerization in the presence of catalysts of aluminum alkyl compounds and titanium salts. The products obtained after sand division of the catalysts can be purified on the edge, either by simple washing or by treatment with acids and swelling solvents. In the latter case, the polymer can then be completely coagulated with methanol. In practice, however, it has been found that small amounts of the alloy, in particular metallic titanium, are formed from the polymer, which is formed during the incomplete conversion between alloy and halide during the preparation of the catalysts. This disadvantage can be overcome if, after the preparation of the catalysts, the unreacted alloy is decanted from a suspension of the catalyst in an inert organic liquid (cf. Example 2). The resulting polymer can then be more easily purified and no longer contains any metal.

The invention is explained by the following examples, in which all percentages are by weight unless otherwise indicated, and all temperatures are given in ° C.

Example 1. 10 g of an aluminum-titanium alloy with a content of 37.2% titanium (atomic ratio Ti: Al = 1: 3), which was ground in color under nitrogen, was introduced under nitrogen into a rotating autoclave with a capacity of ora ring 2 liters, which acted as a ball mill and contained 12 balls of stainless steel with a diameter of 25 mm. Then 35 g of ethyl chloride were injected into the autoclave. The mixture was ground at a temperature of 0 overnight and then the remaining ethyl chloride was completely deposited at a vacuum of 20 mm. Then 600 ml of n-heptane were added and immediately afterwards the ethylene of the autoclave was introduced to a pressure of 30 atmospheres. The temperature rose spontaneously to 103 °, while the pressure rapidly rose to 20 atmospheres. Through additional ethylene, the pressure was brought back to 30 atmospheres and this process was repeated several times, while the temperature remained at 1000, without further heating the autoclave. About 7 hours after the start of the process, the ethylene feed was terminated, the autoclave was cooled, the residual gas was drained and the reaction product, which consisted of an almost white powdery mass, was removed. The polymer was purified at least in part from the non-gnaric products by suspension I of methanol, acidified with hydrochloric acid, and separated by filtration, washed with methanol and dried in vacuo in heat. In this way, 570 g of polyethylene were obtained, which on the X-ray image was found to be crystalline and had a spruce viscosity in tetrahydronaphthalene at 135 ° of 0.80 (pois) and a molecular weight of 23,000.

Example 2. 10 g of an aluminum-titanium alloy with a content of 37.2% titanium and immediately thereafter 40 g of ethyl chloride were introduced under nitrogen gas into a notable autoclave with a capacity of about 2 liters, which acted as a ball mill and contained 12 balls of stainless steel. stal. The mixture was ground for several hours at a temperature of 600 and then unreacted ethyl chloride was evaporated under a vacuum of 20 mm. Finally, 500 ml of n-heptane were introduced into the autoclave. The autoclave cap was removed, the autoclave was set upright and a plug provided with a glass siphon and a valve for introducing nitrogen gas was placed in the inlet of the autoclave. After a short time, about 350 ml of a brown suspension containing no powdered alloy was discarded and collected in a glass bottle. The catalyst suspension was then introduced into a shake autoclave with a capacity of 2000 ml of stainless steel, which was pre-filled with air, and then 300 ml of n-heptane were added. At temperatures of 40 °, ethylene was introduced to a pressure of about 20 atmospheres. The ethylene polymerization started immediately, causing a rapid drop in pressure, while the temperature spontaneously rose to 80 °. Furthermore, ethylene was introduced to a pressure of 30 atmospheres, while the reaction proceeded autothermally at a temperature of 80 °. The polymerization was carried out at a pressure of between 20 and 30 atmospheres, with additional ethylene being introduced over about 6 frames. Dar- —3. after the autoclave was emptied, which was already almost completely filled with a powdery solid polymer with a reddish brown color. The product was suspended in methanol, filtered, washed with methanol and dried in vacuo in heat. 466 g of polyethylene having an ash content of 0.9% and a spruce viscosity of 7.3 in tetrahydronaphthalene solution of 135 ° were obtained, which corresponded to a molecular weight of about 670000.

Example 3. 10 g of a titanium-aluminum alloy with a content of 37.2% titanium and 14 g of ethyl bromide were introduced into the autoclave described above. After about 20 hours of grinding at temperatures between 50 and 60 °, the unreacted ethyl bromide was completely removed and 600 ml of n-heptane were introduced into the autoclave. Then ethylene was introduced to a pressure of 40 atmospheres and the temperature was raised to 90 °. After the pressure dropped to 20 atmospheres, additional ethylene was introduced to a pressure of 40 atmospheres in the autoclave and this procedure was repeated several times for 10 hours. Then, the obtained polymer was drained, which had the same appearance as the polymer in the previous example. After purification, 395 g of polyethylene were obtained, which on the X-ray image showed hag crystalline and had a spruce viscosity of 9.2 and a molecular weight of 960000.

Example 4. 25 g of an aluminum-titanium alloy with a content of 37.2% of titanium, which was pre-ground under nitrogen, was introduced under nitrogen into a rotating autoclave with a capacity of about 2 liters, which acted as a ball mill and millet. Will 10 bullets of stainless steel. Thereafter, 90 g of ethyl bromide were introduced into the autoclave, and the process was continued in the same manner as in the previous example, but the unreacted ethyl bromide was not deposited at the end of the milling process. Then ethylene was introduced into the autoclave to a pressure of atmospheres. The temperature rose rapidly to 90 °, while the pressure loll to 20 atmospheres. By adding additional ethylene, the pressure was restored to pH 40 atmospheres. This procedure was repeated several times within 5 hours. The autoclave was then left to cool, the reaction product, which consisted of a strongly compact polymer mass, was removed and the present inorganic constituents were purified in Iran by a hot acid treatment. 272 g of solid polyethylene with a very high degree of crystallization were obtained, which in tetrahydronaphthalene solution at 135 ° had a granular viscosity of 2.03 corresponding to a molecular weight of about 95,000.

Example 5.

On the same salt as in the previous example, 12 g of an aluminum-titanium alloy with a content of 60% titanium (atomic ratio Ti: Al = 5: 6) were treated with 40 g of ethyl chloride by grinding in a nitrogen gas atmosphere. The unreacted ethyl chloride was then completely removed, the heptane was introduced into the autoclave and then the ethylene was introduced to a pressure of 20 atmospheres. The temperature rose to 100 ° and the autoclave was stirred for a few hours. Small amounts of polyethylene were separated from the reaction product.

Example 6. 10 g of an aluminum-titanium alloy with a. The content of 37.2% of titanium, which was pre-milled under nitrogen, was introduced together with 12 balls of stainless steel with a diameter of 25 mm and 40 g of ethyl chloride into the grinding autoclave described above. The mixture was ground at temperatures between 40 and 50 ° and the unreacted ethyl chloride was removed in vacuo. 150 ml of n-heptane and 300 g of a propylene-propane mixture with a content of 91% propylene were then introduced into the autoclave and the autoclave temperature was raised to 90 ° in 30 minutes. At this temperature the polymerization reaction also occurred and the temperature rose spontaneously to 120 ° in a short time and then slowly returned to 100 °. About 4 hours after the introduction of the propylene, the residual gas was released and methanol was pumped into the autoclave. The reaction product was taken out and purified by treatment with ether and hydrochloric acid in heat, complete coagulation with methanol and filtration and washing with methanol. The resulting polypropylene was then dried in dime in vacuo. 218 g of solid polypropylene were separated, which was fractionated by hot solvent extraction in a Kumagawa extractor, so that the extracted polymer was present at the boiling temperature of the solvent used in the extraction. The acetone extract corresponded to 16.6% of the obtained polymer and consisted of low molecular weight oily products. The ether extract corresponded to 14.7% () eh consisting of solid polypropylene, which on the X-ray image was found to be amorphous and had a spruce viscosity of 0.55 in tetrahydronaphthalene solution of 135 °. The heptane extract corresponded to 26.5% and consisted of air polypropylene, which on the X-ray image was partially crystalline. This fraction had a granule viscosity of 0.74. The extraction residue corresponded to 42.2% of the obtained polymer and consisted of polypropylene, which on the X-ray image was highly crystalline and had a clear viscosity of 3.60 l of tetrahydronaphthalene solution of 135 °, corresponding to a molecular weight of about 230,000.

Example 7. 25 g of an aluminum-titanium alloy having a content of 37.2% titanium and 30 ml of ethyl bromide were introduced under nitrogen into the apparatus described in the above examples. The contents of the autoclave were ground by rotating the autoclave at temperatures of 50 ° C. Then 90 g of a propylene-propane mixture with a content of 82% propylene were heated and the mixture was heated to 85 °. After a few hours, 160 g of propylene-propane mixture were added again and the autoclave was rotated for a further 15 hours at temperatures between 80 and 90 °. The unreacted propylene was removed and the reaction product, which consisted of a sticky solid, was emptied and treated first with methanol and then with acids to decompose the present alloy. 25.5 g of solid polypropylene were separated. This product was fractionated by extraction with hot solvents. The acetone extract corresponded to 39% of the obtained polymer and consisted of low molecular weight solid products. The ether extract corresponded to 13.5% and consisted of amorphous solid propylene with a spruce viscosity of 0.55 in tetrahydronaphthalene solution of 135 °. The heptane extract corresponded to 20.3% and consisted of partially crystalline polypropylene with a spruce viscosity of 0.83. The extraction residue corresponded to 27.2 Vo of the obtained polymer and consisted of highly crystalline polypropylene having a spruce viscosity of 2.35, corresponding to a molecular weight of about 110,000.

Example 8. 12 steel beads and 10 g of freshly prepared titanium-aluminum alloy spans with a content of 111.9% titanium (atomic ratio Ti: Al = 1: 9) were introduced into the grinding autoclave described above. The autoclave was sealed and evacuated, then 40 g of ethyl chloride was introduced and the whole mass was ground at Indian temperatures of 40 and 50 °. The joke-treated ethyl chloride was then removed in vacuo with 400 ml of n-heptane ocb. 240 g of propylene were introduced into the autoclave. The temperature was raised to 100 ° and the autoclave was rotated for about 5 hours. Then the reaction product was extracted and purified in the same manner as in the previous examples. 45 g of white solid powdered propylene were obtained.

Example 9. 10 g of a titanium-aluminum alloy with a content of 37.2% titanium and 40 g of ethyl chloride were introduced under nitrogen into the grinding autoclave described above and the whole mass was ground at temperatures between 60 and 70 °. All the ethyl chloride was then removed under a vacuum of 20 mm and 100 ml of n-heptane and 160 g of penten-1 (Philipps, pure) were introduced. The autoclave was rotated at a temperature of 95 ° for about 5 hours. Then, 100 ml of methanol was pumped into the autoclave, which was opened and a highly viscous product was taken out. This product was purified by dissolving in an ether-heptane mixture, treating with hydrochloric acid and following complete coagulation with methanol. The resulting white solid product was filtered off and dried under vacuum in heat. 135 g of solid polypentene with an ash content of 0.06% were obtained, which was then fractionated by extraction with hot solvents.

The acetone extract corresponded to 41.6% of the total polymer obtained and consisted of low molecular weight oily products. The extract obtained with ethyl acetate corresponded to 16.7% and consisted of a waxy solid product. The ether extract corresponded to 32.9% of the whole polymer and consisted of partially crystalline polypentene. The heptane extract corresponded to 8.75% and consisted of polypropylene, which on the X-ray image proved to be highly crystalline.

Claims (5)

1. A process for the preparation of catalysts for the polymerization of ethylene and higher α-olefins to substantially linear high molecular weight polymers having a regular structure, characterized in that halogen-containing organic compounds are reacted with aluminum titanium alloys. Process according to Claim 1, characterized in that halogen-containing compounds of the general formula RX are used, in which X represents halogen and R represents an alkyl or aralkyl radical, such as alkyl or aralkyl chloride, in particular ethyl chloride. Process according to Claims 1 and 2, characterized in that the alloy is ground with the halogen-containing compound in an inert atmosphere at temperatures below 60 '. Process according to the patent claims in ---- 3, characterized in that aluminum and titanium in the alloy used are present in an atomic ratio between 1: 1 and 10: 1. 4. A process according to claims 1-4, characterized in that the reaction is terminated before the final consumption of the halogen-containing compound and that the excess of this compound is deposited after the completion of the reaction. 5. Process according to claims 1-5, characterized in that the reaction product is separated from unreacted alloy by suspension in an inert vbitic and subsequent decantation. Request publications: