DE1018225B - Process for the polymerization of ethylene or propylene - Google Patents

Description

Process for the polymerization of ethylene or propylene object of the invention is a process for the polymerization of ethylene or propylene alone or of ethylene mixed with propylene or other monoolefins in the presence an oxidic catalyst to products with a molecular weight of at least 300, which is characterized in that the starting materials are at temperatures between 130 and 325 ° in the presence of at least one - alkali aluminum hydride or of an alkaline earth metal hydride and at least one oxide of a metal of Group VI a of the Periodic Table, which is applied to an inert support, polymerized or copolymerized. The yields of solid polymers are in Comparison with the yields that were previously obtained when using oxides below hexavalent Group VI a metals were obtained, increased significantly. According to the invention arise mainly high molecular weight products which are solid under normal conditions.

The process according to the invention is carried out at temperatures between 130 and 325 ° C., preferably between 100 and 2-60 ° C., and at pressures between about atmospheric pressure and 1050 kg / cm2 or more, preferably between 14 and 350 kg / cm2 or at about 70 kg / cm2. The normal solid product tends to accumulate on or in the solid catalyst. It is therefore expedient to feed a liquid medium to the reaction zone which simultaneously serves as a reaction medium and as a solvent for the solid reaction products. Suitable liquid reaction media for the polymerization are hydrocarbons, especially aromatic hydrocarbons, such as benzene, toluene or xylenes. For the polymerization of propylene, less easily alkylatable reaction media such. B. cycloparaffins, such as cyclohexane or decalin (decahydronaphthalene), or paraffins, such as isooctane, are preferred. - _ The process leads to polymers with a large variation in molecular weights and the corresponding physical and mechanical properties, which depend on the selection of the process conditions. The process according to the invention is characterized by an extraordinary elasticity both with regard to the process conditions and with regard to the products obtainable here. With the help of this process one can produce ointment-like homopolymers of ethylene with an approximate molecular weight between 300 and: 700, wax-like homopolymers with an approximate specific viscosity (- 105) of about 1000 to 10000 and tough resinous homopolymers of ethylene with an approximate specific viscosity Establish viscosity from 10,000 to over 300,000 [ (r @ ,. e @ -1) 105]. Under the term “tough; Resinous polyethylene, as it is mentioned in the present description and in the claims, is a polymeric product with an embrittlement point of below -50 ° C (AST-TH method - D 746-51 T), with a notched impact strength of over 0.277 -inkg per 2.5 cm notch (ASTM --- method D 256-47 T-Izod machine) and a minimum ductility at room temperature (25 ° C) of 100 ° / o.

The process can also be used for the copolymerization of ethylene with others lfonoolefins, e.g. B. propylene can be used. The molar ratio of ethylene to propylene can range from about 0.1 to about 10. The propylene alone can rubber-like ones using the catalysts of the present invention Polymers polymerized in addition to the formation of oily and ointment-like solid substances will. Other suitable monoolefins are e.g. B. n-butylene, isobutylene, tert-buty ethylene, generally in the range of about 1 to 25 percent by volume on ethylene, can also be used.

The use of metal hydrides of the type claimed has many essentials Advantages compared to processes in which the metal oxy dcatalysts mentioned can be used alone. So can in the presence of the metal hydrides and metal oxides the V I a group high yields of solid polymers? from which ethylene can be obtained. The catalysts also have a long service life. The desired physical and chemical properties can be determined by controlling the reaction variables, as can be seen from the following description and the exemplary embodiments, can be varied as required.

The alkali-aluminum hydrides can be obtained by reacting the corresponding alkali hydride with Al C13, usually under vacuum or with a protective gas (to prevent the ingress of moisture, C 02 or oxygen) and in the presence of a solvent for the hydrides, in which the alkali chloride that is formed during the reaction is insoluble: wherein M is an alkali metal. The solvent is then removed from the M A1 H4 in the usual way, e.g. B. by vacuum distillation removed.

The mode of action of the metal hydride has not been clarified. The metal hydrides alone are not catalysts for the polymerization of ethylene or propylene to high molecular weight products.

It was also found that ethylene is converted into a normal solid polymer can be converted by means of the claimed catalysts without a pre-reduction stage is switched on, which when using metal oxides of the VI a group as sole catalysts is necessary. Oxides of molybdenum with a minor Valence than 6 are related as catalysts for ethylene polymerization with the three difficult to reduce metal oxide carriers: -; - aluminum oxide, titanium oxide and zirconium oxide, are known. In the presence of the claimed metal hydrides can Metal oxide catalysts of the VI a group not only on aluminum oxide, titanium oxide or Zirconium oxide are used, but also on other carriers such. B. silica gel, Kieselguhr, diatomaceous earth, silica-aluminum oxide, aluminum silicates such as clays and bleaching earth. A hard reducible metal oxide is used as a carrier for the Metal oxide catalysts preferred, e.g. B.; -Aluminum oxide.

The amount of alkali or alkaline earth aluminum hydride used can be between about 0.001 and 2 parts by weight per part by weight of the metal oxide catalyst (Total weight of the solid catalyst), especially between about 0.05 and 0.5 parts by weight, be. The optimum conditions can be found for special cases by simple trial tests can be easily determined taking into account the quantitative ratio between Medium and the catalyst, the catalyst itself, the temperature, the pressure and the type of product you want. Generally, Li A1 becomes H4 in a ratio from about 0.05 to 0.5 parts by weight to 1 part by weight of molybdenum oxide catalyst in the presence of about 5 to 2000 parts by volume of the liquid reaction medium 1 part by weight of the molybdenum oxide catalyst applied.

The proportions of the carrier, based on the metal oxide, can be varied over a relatively wide range, so that each component can be at least about 1 percent by weight of the other. The usual ratios here are from about 1:20 to 1: 1 or about 1:10 of the carrier substance. You can use an aluminum oxide d-metal oxide catalyst with a content of about 1 to 80%, preferably 5 to 35 or 10%. use on metal oxide. The carrier materials for catalysts, such as γ-aluminum oxide, titanium oxide and zirconium oxide, can be produced by various known processes. The application of the molybdenum oxides or the oxides of the other metals of the VI a group to these carriers can also be carried out by known methods, such as those described, for. Described in U.S. Patents 2,692,257 and 2,692,258. Excellent results have also been obtained with catalysts such as those used in hydroforming. The word hydroforming is used to designate processes as described in U.S. Patents 2320147, 2388536, 2357332 .

Molybdenum oxide or other compounds of .L \ lolybdenum and oxygen, such as cobalt molybdate, can be introduced into the catalyst support in a known manner, e.g. B. by impregnation, by common precipitation, by common gelling or adsorption. The catalyst support and / or the finished catalyst can be stabilized in a known manner, similar to the hydroforming catalysts, by heating. Cobalt molybdate catalysts can be prepared in accordance with U.S. Patents 2393288, 2486361 . Cobalt, calcium, nickel and copper salts of chromium, tungsten or uranium acids can also be used with a carrier.

The catalyst can be treated with silica (US Patents 2437532 and 2437533) or with aluminum orthophosphate (US Patents 2440236, 2441297) or with other known stabilizers or modifiers. The catalyst can contain calcium oxide (US Pat. Nos. 2,422,173, 2,447,043), or the support is formed by zinc aluminate spinel (US Pat. No. 2,447,016). Finally, it can also contain considerable amounts of zirconium or titanium oxide (US Pat. Nos. 2,437,531, 2,437,532). Oxides of other metals, e.g. B. des: magnesium, nickel, zinc, chromium, vanadium, thorium, iron, can be present in small amounts, namely below 10 percent by weight of the total catalyst weight.

Although a reduction of the Mo 03 catalysts is not necessary, if these are used in the presence of alkali or alkaline earth aluminum hydrides, a reducing treatment is preferred. The reducing treatment of the Trioxides of hexavalent metals are preferably obtained with hydrogen. It can but also other reducing agents, such as carbon dioxide (water gas, synthesis gas), sulfur dioxide, Hydrogen sulfide, reducing hydrocarbons, can be used. hydrogen Can be used as a reducing agent at temperatures between about 350 and 850 ° C, especially between 450 and 650 ° C. The partial pressure of the hydrogen in the reduction process can be varied from pressures below atmospheric, e.g. B. 0.0451cg / ctn2, up to the relatively high pressures of 210 kg / cm2 or more. It will be the easiest Reduction process carried out with hydrogen at atmospheric pressure.

Lithium aluminum hydride as an extremely active reducing agent reduces and activates catalysts with metal oxides of the hexavalent VI a group even at temperatures down to 35 ° C, although it is mainly between about 100 and 3009 C is used. In practice, for. B. a catalyst that a free or chemically bound trioxide a metal of the VI a group contains, with a suspension of LiA1H4 in a liquid hydrocarbon (solvent) Treated that about 0.01 to 1 part by weight of Li Al H4 to 1 part by weight of the solid Contains catalyst. Sodium hydride (or sodium -I- H2) causes reduction of the Catalysts at temperatures above about 180 ° C and can be in the same Amount to be used like the Li Al H4.

The reducing treatment of the metal oxides of the VI a group can be carried out by Analysis followed and monitored by means of a sulfuric acid solution of cerium sulphate will. This allows the average valence state of the molybdenum oxide or other metal oxides of a catalyst can be precisely determined. In determining the average valence state of the metals in the catalysts, such as of the partially reduced Mo 03, which is applied to hard-to-reducible metal oxides the total molybdenum content and the number of milliequivalents of the Standard oxidizing agent required is the partially reduced molybdenum oxide to oxidize again to Mo 0s, be known. A suitable oxidation process exists in that to about 1 g of finely ground, freshly reduced catalyst in one 250 ml 25 ml 0.1 n cerium sulphate solution Erlenmeyer flask that can be closed with a glass stopper and 25 ml of sulfuric acid 1: 1 added «-erden. This mixture is at room temperature Subjected to rapid stirring for 4 days. The solid residue was filtered off and the excess cerium sulfate solution by adding excess normal ferrous solution certainly. The ferric solution was made with normal ceria solution using ferroo-phenanthroline back-titrated as an indicator. All of the molybdenum in the sample is dissolved by dissolving of the sample in a sulfuric acid-phosphoric acid solution, reduction of the molybdenum in a reduction device according to J o n e s, taking up the reduced solution in iron (3) alum, Determine titration of the obtained ferrous ion with normal cerium sulfate solution. From the The values obtained can be used to determine the average oxidation state of molybdenum will.

The partial reduction of molybdenum or other metal trioxides the VI a group becomes up to an average valence state of the catalyst metal between about 5.5 and 2.0, preferably between about 3 and 5.0.

The reducing treatment described above is not just for freshness Catalysts are desirable, but also for catalysts that are produced by the polymerization process have become relatively inactive. In general, it is freed from the polymer Catalyst reduced before it is used again for the polymerization. if the catalyst by simply removing the polymers and reducing with a reducing gas, as described above, no longer reactivated to a sufficient extent can be, it must by extraction with water, ammonium salt solutions or diluted aqueous acids and subsequent burning off of the combustible deposits regenerated with oxygen and finally through a reduction. A detox of catalysts by treatment with dilute aqueous solutions of peracids, such as permolybdenum, pervanadic or pervungstic acids, and reduction with hydrogen can also be done. The catalysts can come in various shapes and sizes be used, e.g. B. as powder, granules, small wings, as crumbled Filter cake, as lumps or as small shaped balls. The common one The form for the catalysts is a granulate with a grain size of about 58 to 1460 meshes / cm2. The polymerizable to be used for the present polymerization Material is mainly ethylene. This ethylene can hydrogen and hydrocarbons, as contained in the refinery gases, e.g. B. methane, ethane, propane, etc., contain. However, it is the use of ethylene so pure and so concentrated preferred as possible.

The access of oxygen, carbon, water or substances containing sulfur to the catalyst should be avoided. By increasing the polymerization temperature, the average molecular weight and density of the products are reduced. With simultaneous use of polymerization temperatures of about 230 and about 250 ° C and z. B. benzene, xylenes, decalin (decahydronaphthalene) or methyl decalines are produced in a continuous process ethylene polymers with specific viscosities (- 105), which are on average between about 10,000 and about 30,000.

The contact time or the throughput speed is dependent on the other variables of the process, on the catalyst, on the desired polymer and the yield chosen to be different. If the olefin, in the liquid reaction medium dissolved, continuously fed and discharged, are the appropriate speeds usually between about 0.1 and about 10, preferably between about 0.5 and 5, preferably 2 volume units of olefin solution / hour / volume of catalyst. As a medium an aromatic hydrocarbon such as benzene, xylenes, tetralin is usually used (Tetrahydronaphthalene), or a cycloaliphatic hydrocarbon such as decalin (Deka; hydronaphthalene). The ethylene or propylene content of such a solution can range from about 2 to 50 weight percent. Preferably is it is about 2 to about 10 percent by weight and about 5 to 10 percent by weight, respectively. It was found that when the Äthylenkonzentra.tion in the liquid reaction medium below about 2%, the molecular weight and melt viscosity of the polymeric product fall off sharply. The degree of polymerization increases with increasing Concentration of the ethylene in the liquid reaction medium to. The speed the formation of solid polymerization products of high molecular weight is not so great that the solubility of the same in the liquid reaction medium under the Reaction conditions is exceeded. Generally it is about 5 to 7 percent by weight Polylnerisat, excluding those amounts that are selectively adsorbed by the catalyst are. Even if Äthv steering concentrations above 10 percent by weight in the liquid Reaction medium can be achieved, so are the resulting solutions of the Polvmeren in the reaction medium are very viscous and difficult to handle. Through this can cause significant splitting and fragmentation of the solid metal oxide catalyst enter, the catalyst with the polymerized solution from the reaction vessel is led away, so that there are greater catalyst losses.

The polymerization takes between about 1/2 and 10 in a batch Hours, but usually between about 1 and 4 hours, being the autoclave is charged with ethylene as soon as the pressure inside the autoclave falls. The weight ratio of solvent to catalyst can be used with flowing Systems vary in a range from about 5 to about 3000 or even higher. The use of high solvent to catalyst ratios caused by the presence of alkali or alkaline earth aluminum hydride in the reaction zone is possible of great importance in order to obtain high yields of polymerizates.

The olefin can be used in the gas phase in the absence of liquid reaction media polymerized by direct contact with the catalysts. However, it is for the purpose of obtaining larger quantities of olefin conversion products and for continuous use Removal of the solid conversion products from the catalyst is expedient, the conversion to carry out the olefin in the presence of appropriate liquid reaction media.

One can also use a solution of the olefin in the liquid reaction medium prepare beforehand and bring this solution into contact with the catalyst.

Different groups of liquid and inert hydrocarbons (also mixtures) can be used for this. It can .z. B. aromatic hydrocarbons, particularly mononuclear aromatic hydrocarbons, such as benzene, toluene, xylenes, Mesitylene and xylene-p-cymene or mixtures thereof can be used. Also tetrahydronaphthalene is useful. You can also use ethylbenzene, isopropylbenzene, sec-butylbenzene, tert-butylbenzene, Ethyltoluenes, Ethylxylenes, n-Propylbenzene, Hemimellitol, Pseudocumene, Prehnitrol, Use isodurol, diethylbenzenes, isoamylbenzenes. Suitable aromatic hydrocarbon reactions can through the selective extraction of aromatic petroleum from the distillates or the residues of the hydroforming processes, from cyclic fractions of cleavage processes and the like.

Various alkylnaphthalenes can also be used, which are listed under the Polymerization conditions are liquid, e.g. B. 1-methylnaphthalene, 2-isopropylnaphthalene, 1-n-amylnaphthalene or the industrial fractions that contain these hydrocarbons contain.

Certain classes of aliphatic hydrocarbons can also can be used for the present procedure. So can different saturated Hydrocarbons (alkanes and cycloalkanes) are used. It can either pure alkanes or cycloalkanes or commercially available mixtures of these substances are used that are freed from the catalyst poisons, z. B. pure naphtha or petroleum products containing alkanes and cycloalkanes. Especially can you can use liquid or liquefied alkanes, e.g. B. n-pentane, n-hexane, 2,3-dimethylbutane, n-octane, isooctane (2, 2, 4-trimethylpentane), _ n-decane, n-dodecane, cycloherane, methylcycloliexane., Dimethylcyclopentane, ethylcyclohexane, decalin, methyl decaline, dimethyl decaline.

Liquid olefins can also be used, e.g. B. n-IIexene, Cyclolie xene, octene, hexadecene.

The liquid reaction medium must be treated with acid from poisons be exempt, e.g. B. with anhydrous p-toluenesulfonic acid or phosphoric acid by Treatment with aluminum halides or other Friedel-Crafts catalysts, with Maleic anhydride, calcium, calcium hydride, with sodium or other alkali metals, Alkali metal hydrides, lithium aluminum hydride, with hydrogen and hydrogenation catalysts, by means of filtration through a column with copper grains or with metals of the eighth Group or a combination of these treatments.

The xylenes are refluxed with a Mo 03A12 03 catalyst and Li A1 H4 (50 cms xylene, 1 g catalyst, 0.2 g Li Al H4) at atmospheric pressure and subsequent distillation of the xylene purified. Cleaning can be even more effective of the solvent by heating it to 225 to 250 ° C either with sodium and hydrogen or sodium hydride in an autoclave.

The temperature control in the course of the polymerization can as a result the presence of a large mass of liquid with a relatively high heat capacity can easily be carried out in the reaction zone. The liquid hydrocarbon medium the reactions can be cooled inside or outside the reaction zone.

If such solvents as xylenes are used, it can easily alkylation of the same by ethylene under the reaction conditions. Propylene is a much more active alkylating agent than ethylene, and if propylene is contained in the supplied substance, it is desirable to be a non-alkylatable Solvents such as decalin. The alkylate (alkylation product) is removed with the ointment-shaped product of the procedure.

It can be separated from it by fractional distillation and, if necessary desired, be returned to the polymerization zone.

An explanatory diagram showing one method by which the The method of the invention can be carried out is shown in. The drawing. The olefin used, e.g. B. ethylene or an ethylene-propylene mixture is through a compressor 10 to an appropriate pressure, e.g. B. between about 35 and 140 kg / cm2, and flows into the chamber 11, in which a reducing agent, like metallic copper at 150 ° C. The gas continues into the chamber 12, in which there is a dehydrating agent such as adsorbing aluminum oxide, anhydrous calcium sulfate, silica gel or an equivalent desiccant, is located. The dried starting material flows from the chamber 12 into the chamber 13, where carbonic acid is removed. The chamber 13 contains a corresponding means, z. B. Sodium hydroxide on asbestos or some other effective means of removal of carbonic acid. The material so purified usually contains less than 50 parts Oxygen to 1 million parts of substance and has a dew point less than -45 ° C. The purified olefin reaches an absorber 14, in which it is on meets a countercurrent of the solvent. The solvent can go to the absorber and to the process by means of the pump 15 through the duct provided with a valve 16 and the heat exchanger 17 are performed. Here it gets to a temperature brought between about 15 and 35 ° C: The back-flowing solvent from the line 61 can also be used to charge the absorber, or it can be used as a be used as sole absorbent. In the absorber 14 is a solution that between about 2 and about 3041o olefin, e.g. B. contains about 7 percent by weight ethylene, produced and then via the valve provided with a line 18 in a Chamber 19 withdrawn for final cleaning. The chamber can contain an active metal or a metal hydride, e.g. B. sodium, or another Alkali metal, an alkaline earth metal, an alkaline earth hydride, an alkali hydride or calcium hydride. This chamber is brought to a temperature between about 100 and 280 ° C. if If the material to be loaded is sufficiently pure, it cannot enter the chamber via a Leave the line shown and be introduced directly into the reaction vessel 25.

From the chamber 19, the ethylene and the solvent are in the Drained line 20, pass through the pump 21 in the heater 22, where they are on the polymerization temperature, e.g. B. between about 200 and 275 ° C. The solution to be polymerized flows from the heater 22 through the line 23 and further through line 24 into the lower part of the reaction chamber 25. Although a A large number of suitable reaction vessels can be used is shown in the drawing only one autoclave shown. It is divided into an upper and a lower part the partition plate 26 divided. A stirring device 2? is in the lower part of the reaction vessel intended. Suitable baffles 28 are arranged ätl the walls. The stirring device can with about 20 to about 1000 revolutions per minute, especially at about 650 Revolutions per minute. It is obvious that an intense Mixing of the catalyst with the metal hydride, the olefinic starting material and the liquid reaction medium here in the lower part of the reaction vessel 25 is reached. The reaction vessel 25 can at the beginning with the catalyst means a safety adding device or a similar device. Further amounts of catalyst can be added as required in the course of the reaction will.

If deemed necessary, anhydrous solvent can be used through the valved line 29 and through - the heater 30 passed through -, where it is heated to a temperature between about 150 and 300 ° C. It then passes into a contact chamber 31 which is provided with a guide plate 32 is, has a stirrer 33 and an inlet 34 for the alkali-aluminum hydride shows. An intimate dispersion of the metal hydride in the solvent is made in the contact vessel 31 reached. The dispersion comes from the upper quiet zone of the contact vessel 31 through the valved line 35 into the line 24 and is by means of the Pump 36 pressed into reaction vessel 25. A convenient method of cleaning of the solvent in the contact chamber 31 is this solvent with to treat an alkahhydride. Usually you take \ TaH and enter it at the same time Metal oxide of the VIa group applied to a support, e.g. B. 10 weight percent Mo 03 to y-aluminum oxide, to. About 3 to about 10 parts by weight of this are used Catalyst to 1 part by weight of alkali hydride at a temperature between about 135 and 270 ° C and a flow rate of the liquid between about 0.5 and 10 volume units of solution / hour / volume of catalyst.

In the reaction vessel 25, the polymerization of ethylene, propylene or the copolymerization of ethylene with other monoolefins is effected at the appropriate temperature and at the appropriate pressure. The usual concentration of ethylene in the solvent entering the reaction vessel is about 10 percent by weight. The effluent from the reaction vessel usually contains a 2 to 5 percent by weight solution of the solid polymer in the solvent. If the production of a homopolymeric ethylene with a specific viscosity (-105) of about 15,000 to 30,000, a melt viscosity of 2-105 to about 5-10 s poise is desired, the temperatures here are preferably between about 230 and 275 ° C. The reaction time can be between about 10 and about 100 minutes.

It goes without saying that in place of a reaction vessel too several vessels connected in parallel or one behind the other can be used. The conditions can be varied for the various vessels. This can the control on the average molecular weight of the reaction product be expanded. It is also arranged differently through the use of a plurality Reaction vessels and appropriately arranged diversions with valves possible, the individual reaction vessels for cleaning and repair from the whole system to switch off temporarily.

The upper part of the reaction vessel 25 forms a calm settling zone, where fine catalyst particles and particles of metal hydrides emerge from the solution of the polymeric product precipitate in the reaction medium and due to their gravity Sink back into the lower, moving part of the reaction vessel. The relatively clear solution of the reaction product in the solvent is from the upper part of the reaction vessel 25 through the line 37 and the expansion valve 38, whereby the pressure falls to a value between approximately 1 and 17 kg / cm2. The reaction mixture flowing out of the valve 38 arrives tangentially in a centrifuge, z. B. a cyclone centrifuge 39, in which the temperature at least to about 150 ° C is held. That from the centrifuge 39 through the valve-fitted Gas leaving pipe 40 consists essentially of non-toxic ethylene. By the line 51 hot solvent can be introduced into the centrifuge 39, to prevent the polymer from being deposited on the walls of the centrifuge.

According to a preferred method, the clear liquid is from the Reaction vessel 25 through valve 38 down to the vapor pressure of the solvent drained while the temperature in the centrifuge 39 is maintained at about 200 °. After this procedure, all of the ethylene and a substantial part of the Benzene removed from the drained liquid of the reaction vessel 25 so that this in the process, d. H. into the reaction vessel (via a line and by means of a pump, which are not specified), can be returned: The proportionately concentrated solution of the polymer can be further treated as described below will.

The solution of the polymer in the solvent is taken out of the centrifuge 39 passed through the pipeline 41 provided with valves to the filter 42. Be here the last fine catalyst particles that may have been entrained separated and carried away via line 43. If desired, the polymeric solution can Exposure to ultrasonic vibrations that cause coagulation of the causes very fine catalyst particles, so that these are more easily filtered off can. The solution of the polymeric product emerges from the filter 42 passed via the line 44 into the cooling device 45, where it is heated to about 90 to 20.degree is cooled to then be discharged into the line 46 to the filter 47. That solid polymeric product is withdrawn from filter 47 at location 48. The solvent or the reaction medium is discharged via line 49. Part of it can be in the valve provided with a line 50, another part in the also with a valve provided line 51, pump 52 and the heater 53 and back to Centrifuge 39, and a final part can be removed from the filter through the valved Line 54 reach fractionation device 55.

The precipitation of the polymer from the solution can be prevented by adding precipitants, such as low-boiling hydrocarbons, e.g. B. propane, such as alcohols, ketones (acetone), can be reached in line 44. The polymeric product of the present process, that leaves the process at point 48 can undergo various further treatments be subjected to remove any remaining solvent in order to crush it, to press, dry and the like m.

The solvent is evaporated in the fractionation device 55. It leaves the device through the line 56 arranged on the head part. A part the steam can be taken from the line 57; however, the steam is more advantageous passed via the line 58 to the cooling device 59. Here the temperature is on reduced by about 20 to 80 ° C. The solvent continues through the pump 60 through the heat exchanger 17 via the line 61 provided with a valve to the absorber 14, where the solvent is used to prepare a fresh olefin solution is used for the polymerization process.

Part of the solvent is from the pump 60 via the with a Valve-provided line 62 passed into the upper part of the absorber 63. The recovered Gaseous parts from the centrifuge 39 and the line 40 pass through the with valved line 64 via compressor 65 through line 66 in FIG the lower part of the absorber 63. Here the olefin is selectively made by the solvent absorbed. Leaves with a content of about 2 to about 10 percent by weight of ethylene the solvent enters the absorber 63 through the valved conduit 67 and enters the line 20, from where it comes to the reaction vessel 25. the unabsorbed gases leave the absorber 63 via the one provided with a valve Line 68.

The liquid reaction products that are above the boiling point of the Boiling solvent, can from the fractionation device 55 through the with a Valved line 69 exit the process. Preferably they will, however via the valve-equipped line 70 into a further fractionation device 71 headed. As a by-product in the present polymerization process an alkylation product obtained to a relatively small extent if an alkylatable aromatic hydrocarbon has been used as a solvent is e.g. B. xylene, wherein the alkylation product by reaction between the alkylatable, aromatic hydrocarbon and ethylene (or propylene, if this is a component was present in the source material). The alkylated, aromatic Hydrocarbons are vaporized and fractionated and left in column 71 same over line 72. It is generally desirable to have at least one Part of the alkylated products through the valved line 73 through to lead the line 41 in order to use it as a solvent in the filter 42. Of the Residue of the alkylation products can pass the system through the valve provided with a valve Leaving line 74, or it can be incorporated as part of the liquid reaction medium into the Reaction vessel 25 are returned.

During the polymerization, relatively small amounts of low molecular weight, ointment-shaped olefin polymer formed. The ointment-shaped products are called Residue from column 71 is removed via line 75 provided with a valve.

Another procedure is followed by the filtration of the finely divided catalyst particles in the filter 42, the dilute solution of the olefin polymers Introduced into a column containing hot water or a mixture of liquid water and contains steam. This heat causes the solvent (or an azeotropic Mixture of solvent and water) quickly distilled off and an aqueous suspension of the solid polymeric parts comprising about 1 to about 5 percent by weight of this Contains polymers. The aqueous suspension of the polymer can be concentrated in the usual way to form a slurry containing about 10 to 15 percent by weight of polymer to obtain. This slurry can then be centrifuged to produce a polymer Obtain product with a low water content, which then carefully under Can be dried using known devices. That with rapid distillation Solvent escaping upwards can be condensed by a lower one separated aqueous layer and distilled again for the purpose of drying and finally with the help of dehydrating agents, e.g. B. silica gel, A12 03 gel treated before it enters the reaction zone for polymerization or into the storage container returns.

Another option is to dissolve the polymers in an aromatic solvent from which the fine catalyst particles already exist removed to dry by spraying.

The following examples are given to illustrate the process. Unless otherwise specified, the process was carried out batchwise as follows. The molybdenum-aluminum oxide catalysts were, with the exception of Examples 2, 1.3 and 14 are used without pre-reduction, so that the average valence of the Molybdenum was 6 before use. The reactions were carried out in autoclaves with a magnetically operated agitator were carried out. The reaction vessel was charged with the solvent and then with the catalyst. at The space in the reaction vessel was made using a pre-reduced catalyst Filled with nitrogen. The hydrides were then added to the reaction vessel in powder form given and the vessel closed under a continuous stream of material to the system air-free to hold. If a non-reduced catalyst was used, was the use of nitrogen was not necessary, and the catalyst was immediate placed in the autoclave. The air remaining in the autoclave was then used during the pressure test purged with nitrogen. The last component was the olefin only after Heat to the reaction temperature in the autoclave. To the catalyst in Susr To keep pension, the magnetically operated, liftable one became Stirrer lifted up as required and lowered back into the solution. the Olefin was added from time to time during the process to reduce the reaction pressure maintain. Hydrogen with a partial pressure of about 7 to 14 kg / cm2 can be added to the olefin pressure if the reaction is not fast enough gets going. By applying the pressure drop as a function of time the process can be followed. In many cases higher yields can be obtained if you have a larger amount of solvent in the reaction zone as a precaution introduces, as one of the reasons for the delay in the process is the formation of semolina on the stirrer, which results from the fact that under the given reaction conditions the solubility limit for the polymer has been exceeded. In the examples means specific viscosity (relative viscosity-1) and relative viscosity the ratio the outflow time of a solution of 0.125 g of a polymer in 100 cm3 of xylene at 110 ° C at the outflow time of 110 cm3 of xylene at 110 ° C. The melt viscosity was after the method of D i e n o s and K 1 e m m, J. Appl. Phys., 17, pp. 458 to 471 (1946), certainly.

The alkali or alkaline earth aluminum hydride activators allow the use of very high and relatively high solvent to catalyst ratios Degrees of polymerization, so that a continuous process, long-lived catalysts and high yields of solid polymers per unit weight of metal oxide catalyst can be obtained.

Example 1 A mixture of 0.5 g of molybdenum oxide, aluminum oxide catalyst with a molybdenum oxide content of 8 percent by weight, 0.1 g Li A1 H4 and 50m1 Xylene was placed in a 100 cc reaction bomb and poured onto a Heated to a temperature of 220 ° C. Ethylene was then purified up into the bomb pressed in to the initial pressure of 63 kg / em2. After an exposure time of one Hour hydrogen was in the reaction vessel up to a partial pressure of 14 kg / cm2 pressed in. Additional ethylene was added over the course of the next hour introduced into the reaction vessel. The ethylene pressure drop was 98 kg / cm2. The reaction gave 4.23 g of tough, elastic ethylene polymer per 1 g of catalyst with a specific viscosity (- 105) of 22 400 and with a ratio of methylene to methyl of over 60 (ratio of methylene groups to CH3 side chains in the polymerization molecule).

B @ oispieil 2 A completely exhausted 8 weight percent was used for the experiment Molybdenum oxide-y-aluminum oxide catalyst used, which comes from a process in which ethylene in the presence of this catalyst, but without activators (hydrides), polymerized into solid products. Were from this exhausted catalyst 5.0 g and 0.5 g of Li Al H4 used. 50 served as the liquid reaction medium cm3 xylene. The mixture was stirred in the 100 cm3 reaction bomb to 230 ° C, whereupon ethylene is pressed into the bomb with an initial pressure of 63 kg / cm2 became. A total pressure drop of 74 kg / cm2 was obtained in 60 minutes. During this time, so much ethylene polymer was formed that the stirring mechanism had to work in a gritty mass. There are 0.75 g of ethylene polymers on 1 g of catalyst. The polyethylene showed a specific viscosity (- 105) of 63,500 and a melt viscosity of 9.5-107 poise. The polymer gave a tough, pliable film.

Example 3 The bomb was made with 0.5 g of 8 weight percent molybdenum oxide-γ-aluminum oxide catalyst (525 to 900 meshes / cm2), 0.17 g LiA1H4, 50 cm3 xylene charged and stirring of the contents heated to a temperature of 229 ° C. As a result, ethylene was up to an initial pressure of 75 kg / cm2 and hydrogen up to a partial pressure of 14 kg / cm2 pressed into the bomb. In 2 hours, the total pressure drop in the reaction vessel was 92 kg / cm2. The reaction produced a tough, elastic ethylene polymer with a specific viscosity 105) of 25 100 and a melt viscosity of 3.15 - 10s poise. 1.18 g of polymer, including the small ones, were added to 1 g of catalyst Lot. obtained at the same time as ointment-shaped ethylene polymer.

Example 4 The insert consisted of 0.5 g of 8 percent by weight Mo, lybdenum oxide-aluminum oxide catalyst, 0.07 g Li Al H4 and 50 cm3 xylene. The ethylene used contained 0.02 to 0.05 mol percent CO. The ethylene was placed in the 100 cm3 autoclave after heating it to 233 ° C. A drop in ethylene pressure of 100 kg / cm2 was observed within 3 hours. The reaction gave 4.84 g of polyethylene per 1 g of catalyst with a specific viscosity (-105) of 29,200 and a melt viscosity of 2.3-106 poise. The Polymerisa.t gave one. tough, pliable film. The examination of the remaining gas showed 0.01 volume percent CO2. In ointment-like polymers, 0.06 g per 1 g of catalyst was determined.

Example 5 50 cm3 of xylene, 0.14 g of 8 percent strength by weight molybdenum oxide-aluminum oxide catalyst Sator and 0.07g Li Al H4 were placed in the 100 cm3 reaction vessel and under Stirring heated to 230 ° C. Then purified ethylene was down to the initial pressure of 55 kg / cm2 pressed into it. This pressure was reduced by temporarily introducing. Maintained ethylene for a reaction period of 250 minutes. at this reaction gave 9.43 g of normal solid ethylene polymer to 1 g of catalyst obtain. The polymer had a specific viscosity (- 105) of 50 500, a melt viscosity of. 3.2 - 107 posse and could - a tough, elastic one Form a film .. In addition, it should be noted that ß the solvent / catalyst ratio was about 350 cm3 / g.

Example 6 The reaction vessel was filled with 0.4 g of 80% molybdenum oxide-aluminum oxide-Ka, ta.lysa, to @ r, 0.06 g Li A1 H4, 50 cm3 xylene are charged and heated to 230 ° C. with stirring. That Ethylene was pushed in up to an initial pressure of 73 kg / cm2, whereupon for the purpose of Maintaining this pressure during the reaction gave ethylene from time to time became. The entire working period was about 4 hours. In response were on 1 g Ka.ta, lyser 10.5 g of solid polyethylene with a specific Viscosity (-105) -of 31000 and a melt viscosity of: 4.5-106 poise. The polymer could be shaped into a tough, elastic film.

Example 7 The reaction vessel was charged with 5 g of molybdenum oxide-aluminum oxide catalyst which contained 8 percent by weight of molybdenum oxide and had a fineness of 525 to 900 meshes / cm 2, as well as 0.5 g of Li A1 H4 and 50 cm 3 of isooctane. The reaction vessel became. The contents were heated to 252 ° C while stirring and propylene was then added until the partial pressure was maintained between 42 and 70 kg / cm2. The total pressure drop of the propylene over the course of the reaction time of 356 minutes was 61 kg / cm 2. A tough, pliable propylene polymer with a specific viscosity (. 105) of 11,700 was formed. Together with some ointment-shaped polymers, it had a CH .: CH. ratio of 8.0.

Example 8 The 100 cni3 reaction vessel was filled with 0.2 g of molybdenum oxide-γ-aluminum oxide catalyst of 8 percent by weight molybdenum oxide and a fineness of 525 to 900 meshes / cm2 charged with 0.06 g Li A1 H4 and 50 cm3 xylene. The reaction vessel was stirred the contents heated to 230 ° C, whereupon ethylene up to a partial pressure of about 70 kg was introduced into the reaction vessel. During the polymerization the Ethylene pressure by supplying additional amounts of ethylene in accordance with the polymerization process maintain. Over the course of the 4 hour reaction time, the total was Pressure drop of ethylene 71 kg / cm2. 1 g of catalyst were used in the reaction 6.4 g of solid ethylene polymer with a specific viscosity 105) of. 14000 and a melt viscosity of 8.0-105 poise. The solid ethylene polymer was transformed into a tough, elastic film.

Example 9 The reaction vessel was filled with 0.42 g of molybdenum-aluminum oxide catalyst, Contains 8 percent by weight Mölybdänoxide, with a fineness of 525 to 900 meshes / cm2, charged with 0.12g Li A1 H4 and with 150 ml specially purified xylene. The volume of the reaction vessel was 250 ml. The reaction vessel was opened while stirring the contents heated to 233 ° C, then pressed in the ethylene up to an initial pressure of 70 kg / cm2, to compensate for consumption by continuously adding ethylene during the polymerization process was maintained. In the reaction, 19 g of solid material would be obtained for 1 g of catalyst and 0.83 g of ointment-shaped polymer of ethylene obtained. The specific viscosity (- 105) of solid ethylene polymer. was 14,400 and the melt viscosity was 4.4 - 105 poise.

Example 10 The 100 cm 3 reaction vessel was filled with 0.14 g of molybdenum oxide-γ-aluminum oxide catalyst, which contained 8 percent by weight of molybdenum oxide and had a fineness of 525 to. 900 masses / cm2, charged with 0.04 g Li A1 H4 and 50 cm3 purified xylene. After the contents had been heated to 230 ° C. up to an initial ethylene pressure of 63 kg / cxn2, anhydrous and carbonic acid-free ethylene was added. The reaction lasted 380 minutes. A solid polyethylene with a specific viscosity (105) of 12,400 and a melt viscosity of 3.9-104 poise was obtained. The yield was 36.2 g per 1 g of catalyst, including 3.14 g of ointment-shaped ethylene polymer per 1 g of catalyst. EXAMPLE 11 The 250 cm 3 reaction vessel was charged with 5 g of a commercially available catalyst which contained 31 percent by weight of chromium oxide in aluminum oxide with a fineness of 130 to 1640 meshes / cm 2. The catalyst was previously reduced by treatment with dry hydrogen at atmospheric pressure for 16 hours at 375 ° C. 0.5 g of Li A1 H4 and 100 cm "of purified lylene were then placed in the reaction vessel and the contents were heated to 230 ° C. with stirring while maintaining a low hydrogen pressure The yield was 1.85 g of solid ethylene polymer with a density of 0.976 at 24 ° C. Example 12 The 250 cm3 reaction vessel was filled with 2 g of a tungsten oxide / zirconium oxide catalyst (130 to 1460 1 bottles / cm =), containing 20 percent by weight of WO3, which was partially reduced over the course of 16 hours by dry hydrogen at atmospheric pressure and 450 ° C. 100 cm3 of purified xylene and 0.3 g of LiAl H4 were also added to the reaction vessel heated with stirring at a low hydrogen pressure to 250 ° C. Thereupon, ethylene freed from water and carbonic acid was pressed in up to an initial pressure of 61 kg / cm2 During the 10-hour reaction, ethylene was added to the reaction vessel in between. 3.78 g of solid ethylene polymers were obtained on 1 g of catalyst, which were shaped into a tough and flexible film. The polymer exhibited a specific viscosity (-105 ) of 18800, a melt viscosity of 2-105 poise and a density of 0.952 at 24 ° C.

EXAMPLE 13 The 100 cm 3 reaction vessel was charged finitely with 1 g of 8% by weight 1 @ lolybdenum γ aluminum oxide catalyst, which was used in the form of a filter cake with a fineness of 130 to 1460 mesh / cm 2. Before use, the catalyst was reduced with dry hydrogen at atmospheric pressure over 16 hours at 480 ° C. In addition, the reaction vessel was charged with 0.2 g of NaAl H4 and 50 cm3 of purified xylene. The contents of the reaction vessel were heated to 250 ° C. with stirring, whereupon ethylene was injected up to an initial pressure of 60 kg / cm2. The reaction lasted 20 hours, during which time ethylene was injected in between. The entire Äthylendruckabfall was 45 kg / cm2. In this experiment, 45 g of solid ethylene polymer was obtained on 1 g of catalyst 1, which became a tough; flexible film has been deformed. The solid polymer had a melt viscosity of 4.8-10s poise and a density of 0.983 at 24 ° C ..

Reispiiel -.- 14 The 100 cm3 reaction vessel was filled with 6 g of 8 weight percent Molybdenum oxide-y-aluminum oxide catalyst is charged, which has a grain size of 525 up to 900 meshes / cm2. In addition, 0; 5 g Li A1 H4 and 70 em3 liquid Put propylene in the jar. The reaction was carried out at 187 ° C. and at an initial pressure of propylene of 217 kg / cm2. The total pressure drop - of propylene was 44 kg / cm2. In this reaction, 0.2 g of a soft propylene polymer was added to 1 g of catalyst with a specific viscosity (10s) of 10,000. The reaction proceeded without a liquid reaction medium. - Example 15 Magnesium aluminum hydride, that by reacting _ magnesium bromide with lithium aluminum hydride in, anhydrous Diethyl ether (method by E. Wibejjg: and R. -Bauer, "Z. Naturforsch., 5 b, S, 397. _ [195D)) is used. The lithium bromide by-product in this conversion is only partially soluble in the ether and falls from it during the implementation partly from: "The lithium bromide precipitate is filtered off. The Ether is made from the filtrate with the help of a stream of dry nitrogen and through subsequent evacuation at temperatures up to 100 ° C removed. The received Magnesium-aluminum hydride preparation contains about 50% lithium bromide as a by-product, however, this reduces the effectiveness of the magnesium-aluminum hydride as an activator with oxides of metals of group VI a in processes. for the polymerization of olefins. not affected.

A 250cc stainless steel Magne Dash autoclave fitted with a magnetically powered, whirling stirrer was cleaned with 100 cc Toluene charged under a nitrogen atmosphere. The taluol was drained and Carbo-nate-free by using lithium aluminum hydride and a catalyst from 8 percent by weight Mo.03 on activated aluminum oxide for 16 hours at atmospheric pressure heated to boiling, then distilled under nitrogen and stored over sodium became. 1 g of a catalyst was also placed in the reaction vessel 16-hour partial reduction of 8 percent by weight of Ma03 based on γ-aluminum oxide had been applied, made with hydrogen at 480 ° and atmospheric pressure had been. Then 0.52 g of the (LiBr-containing) Mg (AIH4) 2 given. It was flushed with nitrogen and the reaction mixture under Stirring heated to 230 °, whereupon dried and CO.-free ethylene up to one Initial pressure from. 81.2 kg / cm2 was introduced. The implementation was 20 hours carried out with stirring, with ethylene was pushed in from time to time. To This time was allowed to cool to room temperature. The gases were blown off and the contents with absolute methanol and then with distilled water treated. Then the container was opened and the polymer was used extracted from the solid catalysts by hot xylenes. Solid polyethylene high molecular weight were precipitated from the solution by bringing it to room temperature Was cooled, and separated by filtration, the filtrate being a xylene solution was obtained containing polyethylenes of lower molecular weight. That. High molecular weight polyethylene was exposed to air and then 1 hour dried in vacuo at 105 °. The polymerization gave 4.2 g of a tough, solid Ethylene polymer with a high molecular weight, its specific. Weight (d = 24 ° / 4 °) 0.9557 and its melt viscosity was 3.1-106 poisa as determined by the method. von Dienes and Klemm, J. Applied Phys., 17, pp.458-471 (1946). In addition, 0.2 g of grease-like polyethylenes were produced in xylenes Were soluble at room temperature.

In experiments that - without any activator according to the one described above general procedure using 5 weight percent pre-reduced Mo03-y-alumina catalyst were carried out, were only 0.5 g of solid ethylene polymer per g of catalyst obtained at 230 ° and 70 kg / cm2 initial ethylene pressure.

- Example 16.

The procedure of Example 15 was repeated using 0.46 g of the magnesium aluminum hydride preparation and 1 g of a catalyst prepared by partial reduction with hydrogen of 31% by weight of CrO 3 applied to activated alumina under the same conditions. how the molybdenum oxide-alumina catalyst of Example 15 was prepared. The polymerization gave 1.65 g of an ethylene polymer, its. specific gravity (d = 24 ° / 4 °) 0.9642 and its melt viscosity was 1.55-104 poise, and also 0.15 g of grease-like polyethylene.

The polymers. Made by the process of the present invention can, if desired, be post-treated in the following way: to make them ready to use for different purposes or to give them special properties. to rent. So the polymers. subjected to a strand process, rolled, formed into foils, sprayed or transformed into sponges or latices. In the Polyäthylen.e can. Anti-aging agents, stabilizers, fillers, Extenders, plasticizers, pigments, insecticides, fungicides and the like Substances are incorporated. The polyethylenes can be used as paints and binders as well as for other purposes.

The; polymers produced by the present process, especially Polymers with a high specific viscosity can be reduced with Polyäthylen.en Molecular weight are mixed. To this. Stiffness or other desired To give properties. You can also use any desired amount of hydrocarbon oils, Grow, e.g. B. paraffin or petroleum waxes, ester waxes, with high molecular weight Polybutylenes and mixed with other organic substances. Small quantities (between 0.01 and about 1 (l / o) can be used with hydrocarbon lubricating oils for the purpose of increasing the viscosity index and to reduce the oil consumption when using them are added in engines.

The products with a molecular weight of 50,000 and more can, used in small amounts to significantly increase the viscosity of the liquid Hydrocarbon oils and also can be used as gelling agents for such oils. the polymers made by the present process. can use different chemical Reactions are subjected, e.g. B. halogenation and dehalogenation, one Sulfohalogenation using sulfuryl chloride, a sulfonation.

Claims (5)

PATENT CLAIMS: 1. Process for the polymerization of ethylene or propylene. alone or by. Ethylene. in a mixture with propylene or other monoolefins at elevated temperature in the presence of an oxyd.ischen catalyst to products with a molecular weight of at least 300, characterized in that these starting materials at temperatures between 130 and. 325 ° in the presence of at least one alkali aluminum hydride or an alkaline earth aluminum hydride and at least one oxide of a metal from group VI a of the Periodic Table, which is applied to an inert support, polymerized or copolymerized. 2. Procedure according to Claim 1, characterized in that the polymerization or copolymerization is carried out in a liquid hydrocarbon. 3. The method according to claim 1 or 2, characterized in that the catalytically active metal oxide used, especially molybdenum trioxide, before its use as a catalyst up to a medium one Significance level between 2 and 5.5 is reduced. 4. The method according to claim 1, 2 or 3, characterized in that the catalytically active metal oxide used applied to a poorly reducible metal oxide, especially y-alumina, as a carrier will. 5. The method according to any one of claims 1 to 4, characterized in that the polymerization or copolymerization is carried out at pressures between about 1 and 1000 kg / cm2. Documents considered: German Patent No. 836 711; German patent applications. B 7335IVc / 39c and Z 771 IVc / 39c; British Patent No. 682420; U.S. Patent No. 2212155; Franz K rczi 1, Kurzes Handbuch der Polymerizationstechnik, 1940, Vol. 1, p. 213; Chemical Abstracts, 1938, p. 1900 (2).