DE1040245B - 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 to form products with molecular weights of at least 300 in the presence of an oxide catalyst, which is characterized in that the starting material at temperatures between 75 and 325 ° C in the presence of a borohydride of a metal whose electronegativity according to the Pauling scale is at least 1 and its borohydride compound with Water reacts violently at 25 ° C with the formation of hydrogen, and at least one Oxide of a metal of group V1 a of the periodic table polymerizes or copolymerized.

The yields of solid polymer are in comparison to processes which have hitherto been used with the sole use of oxides of the metals of group VI a with value levels below 6, significantly increased. According to the invention The result is mainly high molecular weight polymers that are solid under normal conditions.

The process is carried out at temperatures between about 75 and 325-- C, preferably about 130 and 260 C, and at pressures between about atmospheric pressure and 1050 at or higher, preferably between about 14 and 350 at or at about 70 at. Those produced in the catalytic conversion are below normal Conditions of solids tend to build up on and in your solid catalyst. It is therefore advantageous to feed a liquid medium to the reaction zone which on the one hand as a reaction medium and on the other hand as a solvent for the solid Reaction products is used. Suitable liquid reaction media for the polymerization are various, particularly aromatic hydrocarbons, e.g. B. benzene, toluene or the xylenes. During the polymerization of propylene, they become less easily alkylatable Reaction media, e.g. B. Cycloparaffins, such as cyclohexa, n or decalin (decahydronaphthalene), or paraffins. z. B. isooctane, preferred.

The: Transfer of ethylene or propylene-containing gas can also carried out in the absence of a liquid reaction medium or solvent will. It must then be the catalyst on which the solid polymeric conversion product is deposited has accumulated, treated from time to time inside or outside the conversion zone to remove the conversion products and, if necessary, to further Use to reactivate or regenerate.

The method according to the invention is extraordinarily versatile both with regard to the process conditions and those that can be produced with it Products marked. With the help of the procedure one can get to grease-like Ethylene polymers with an approximate molecular weight between 300 and 700, to wax-like ethylene homopolymers with an approximate specific viscosity (105) between about 1000 and 10000 and too tough, resinous ethylene homopolyers with an approximate specific viscosity (-105) between 10000 and more than 300,000 [(? Irel - 1) - 105] arrive. Under the expression "tough, resinous polyethylene" is understood to mean a polymer whose embrittlement point is below - 50 ° C (ASTM Method D 746-51 T), the notched impact strength of which is greater than 0.28 mkg per approximately 5 cm Notch is (ASTM Method D 256 -47 T - Izod) and its minimum elongation at room temperature (25 ° C) is 100 ° / o.

The process according to the invention can be used to carry out the interpolymerization, of ethylene with other monoolefins such as propylene, n-butylenes; Isobutylene, tert-butylethylene, usually in amounts between 1 and 25 volume percent based on the weight of the Ethy Jens to perform.

The metal borohydride used in the present process react violently with water at 25 ° C to form hydrogen. Under this violent reaction with water is said to be rapid, and at times practically instantaneous Reaction can be understood. As boron hydrides that can be used here come those of lithium, magnesium, beryllium, aluminum, thorium, hafnium, zirconium and uranium in question. These reactive borohydrides are all also notable through the ability to produce polyvalent metal salts, e.g. B. the Ti in Ti C14, to trivalent To be able to reduce Ti. They are also characterized in that the Borohydride linked metals have an electronegativity on the scale of P au 1 i ng of at least 1 (cf. L. P aul i ng, "The Nature of the Chemical Bond", Cornel University Press [1939] p.64, and D. T. Hurd, "Chemistry of the Hydrides", John Wiley & Sons, Inc., N.Y., 1952 and Hoekstra and Katz, I. Am. Chem. Soc., 71, pp. 2488 to 2492, July 1949).

The use of a reactive metal borohydride in the reaction zone is of practical importance in several ways, especially when compared to Processes in which the metal oxide analyzer is only used on its own. So can in the presence of both the reactive metal borohydride and the metal oxide catalyst high yields of solid polymers can be obtained. The metal oxide catalyst can in the presence of large amounts of the liquid. Reaction medium act, he retains its strong polymerization activity over long periods of time (lifetime of the catalytic converter). The desired. physical and chemical properties the polymers can easily be adjusted by adjusting the reaction conditions in question be achieved; related details can be found in the description and the later examples.

The function or functions of the reactive metal borohydride in, the present proceedings are not entirely clear. The reactive metal borohydride increases the effect of the oxide catalysts of metals of group V1 a and increases as a result, the polymer yield is sometimes astonishing.

Prior to this invention, oxides of molybdenum were valued under 6 as catalysts for the polymerization of ethylene to under normal conditions solid polymers known that only on one of the three difficult to reduce Metal oxides: y-aluminum oxide, titanium oxide and zirconium oxide were applied. In The metal oxide catalysts can use reactive metal borohydrides of group VI a not only applied to aluminum oxide, titanium oxide or zirconium oxide Rather, they can also be used on many other carriers for the polymerization of Ethylene-containing raw materials for the purpose of forming solid substances under normal conditions Polymers, e.g. B. on silica carriers, such as silica gel, kieselguhr, diatomaceous earth; Silica-aluminum oxide, aluminum silicates, the various clays and bleaching earths be applied .. The use of a difficult reducible is particularly advantageous Metal oxide as a carrier for the metal oxide catalyst, e.g. B. of y-aluminum oxide.

The amount of reactive metal borohydride used in the process can be between about 0.005 and 2 parts by weight per part by weight of the metal oxide catalyst (i.e. total solid catalyst weight) will vary. The optimal amounts can in special cases by simple tests on a small scale with the respective Starting materials, the liquid reaction medium, a certain ratio from reaction medium to catalyst, the catalyst, the temperature, the pressure and the type of product desired can easily be determined. Usually, Li B becomes H4 in amounts between about 0.05 and 2 parts by weight per part by weight of molybdenum oxide catalyst at ratios between about 5 and 2000 volumes of liquid reaction medium per Part by weight of molybdenum oxide catalyst applied.

The respective amounts of carrier in relation to the catalytic metal oxide can vary within relatively wide limits in such a way that each component is present in amounts of at least about 1 percent by weight. The usual metal oxide to carrier ratios range from about 1:20 to 1: 1 or about 1:10 z. B. finished aluminum oxide-metal oxide catalysts with 1 to 80010, preferably approximately. 5 to 35% or about 100/0 catalytic metal oxide applied to the support.

The y-aluminum, titanium- and zirconium oxides can be prepared by various known methods will. Likewise, the oxides of molybdenum or other metals of the group VIa incorporated in or on these supports by any known method be deposited.

The molybdenum or any other molybdenum-oxygen compound, z. B. cobalt molybdate, the catalyst support by any known method be incorporated, e.g. B. by impregnation, simultaneous precipitation, a kind of gelation and / or adsorption. The catalyst mass and / or the finished catalyst can known in the manufacture of catalysts for hydroforming Way to be stabilized in the heat. Cobalt molybdate catalysts can according to U.S. Patents 2,393,288 and 2,486,361. Likewise can Cobalt, calcium, nickel and copper salts of chromic, chromic, tungsten and uranium acids can be used with or without a carrier.

The catalyst can be stabilized with silica (U.S. Patents 2437532/3) or with aluminum orthophosphate (U.S. Patents 2440236 and 2441297) or other known stabilizers or modifiers. The catalyst can contain calcium oxide (U.S. Patents 2442172 and 2447043) or the mass can be in the form of a zinc-aluminate spinel (U.S. Patent 2447016) and it can contain considerable amounts of zirconium oxide or titanium oxide (U.S. Patents 2437531/2). Oxides of other metals, e.g. B. of magnesium, nickel, zinc, vanadium, thorium, iron, etc., can be in small. ie amounts below 10 percent by weight. based on the entire catalyst, be present.

Although, as already stated, the metal oxide catalysts do not need to be subjected to a reduction treatment when they are used in the presence of a reactive metal borohydride, such a reduction is nevertheless recommended. This reducing treatment of the oxide of a hexavalent metal from Group VIa is preferably carried out with hydrogen; but it can also use other reducing agents such. B. carbon monoxide, mixtures of hydrogen and carbon monoxide (water gas, synthesis gas, etc.), sulfur dioxide. , Hydrogen sulfide, reducing hydrocarbons, etc. can be used. Hydrogen can serve as a reducing agent at temperatures between about 350 and 850 ° C, especially between 450 and 650 ° C. The hydrogen partial pressure in the reduction can be between a negative pressure of, for. B. about 0.007 at (absolute) and relatively high pressures, e.g. B. up to 210 atm or even higher, fluctuate . The simplest reduction can be carried out with hydrogen at around atmospheric pressure. The partial reduction of the metal oxide catalyst, in which the metal is present in its hexavalent form, can take place in the presence of the reactive metal borohydride which is claimed and which acts as an activator before the polymerization.

It was observed that an induction period prior to ethylene polymerization can be turned off or significantly reduced if one. the hydrogen in the one with solvent. Charged with ethylene, the metal oxide catalyst and borohydride Reaction vessel under pressure, e.g. B. at 0.7 to 63 at, preferably 7 to 28 at, is injected. Under these conditions only a small part of the ethylene is reduced to ethane.

Lithium aluminum hydride, an exceptionally effective reducing agent, reduces and activates oxides of 6-valent metals containing group VI a Catalysts themselves. At 35 ° C, although generally temperatures between. 100 and 300 ° C can be used. In the practical implementation z. B. becomes a free or chemically bound Mo03 (e.g. bound as CDM004.) containing catalyst with a suspension of Li A1 H4 in a liquid hydrocarbon solvent in a weight ratio of about 0.01 to 1 Li A1 H4 to solid catalyst treated. N atrium hydride (or sodium + H,) acts on catalysts made from oxides of 6-valent Group VI a metals, e.g. B. 11o 03, reducing at temperatures above about 180 ° C and can be used in the same proportions as Li A.1 H4. The responsive one Metal borohydride of the present invention can be made under practically the same conditions for the partial reduction of catalysts consisting of metal oxides of group VI a can be used, such as Li A1 H4.

An analysis can be carried out on the reduction of the metal oxide of group VIa with Cerisu, lfat-sulfuric acid solution for the exact determination of the average Valence level of the molybdenum or another metal oxide in the Ka.taJysa, tor connect. To determine the average valence of the metals, e.g. B. the partially reduced Mo03 on a difficult to reducible metal oxide, e.g. B.;, - aluminum oxide, one must determine the total content of molybdenum and the number of Milliäduiva.lente of a standard oxidizing agent, which are necessary for reoxidation of the partially reduced molybdenum oxide to M003, know. A suitable oxidation method is that about 1 g of the finely ground, fresh, reduced catalyst in a glass stopper Weigh 250 cc Erlenmeyer flask and add 25 cc of 0.1 N cerium sulfate solution and 25 cc of a sulfuric acid (1: 1) are there. This mixture is left at room temperature stand for 4 days, stirring frequently. The solid residue is then filtered off and the excess Cerisulfa.tlösung by adding excess standard ferrous salt solution determined who in turn with a normal cerium salt solution using a Ferro-ortho-phenanthroline indicator is titrated. The entire \ folvbdän in the Sample is made by dissolving the sample in a sulfuric acid-phosphoric acid solution, Reduction of the molybdenum in, a Jones reduction apparatus, taking in the reduced Solution in ferric alum and titration of the ferrous ion obtained with standard cerium sulfate solution certainly. The oxidation state of the molybdenum oxide can be determined from the values obtained will.

The partial reduction of molybdenum oxide or some other trioxide of a metal of group VI a is carried out so far that the average Valence level of the catalytic metal in the catalyst between about 2 and. 5.5, preferably about 3 and 5.

The reduction described here is not only applicable to fresh catalysts expedient, it is also necessary in the case of catalysts that result from the polymerization have become relatively inactive. As will be explained, it must Polymer formed in the polymerization reaction at intervals or continuously removed from the catalyst particles, preferably with the aid of solvents will. It is usually necessary or appropriate to reduce a catalyst, which has been freed from the polymer to a certain extent in this way before it is further used in the polymerization. If a catalyst doesn't longer enough active by simply removing the polymer and reducing with a reducing gas can be made in the manner described here he by extraction with water or dilute acids and subsequent burning combustible deposits are regenerated with oxygen before the actual reduction. Under certain circumstances, the catalysts can also be detoxified by treating them with dilute aqueous solutions of peracids, such as. B. Permolybdenum, Pervanadine or perwolfric acid, and subsequent reduction of the catalyst with hydrogen be displayed.

The catalysts can come in various shapes and sizes, e.g. B. as powder, granules, small globules, broken filter cakes, lumps :, cookies and the like. A suitable form for the catalysts is that of Granules with a size of 58 to 1460 meshes per cm2. Both the metal oxide catalyst sator as well as the solid \ letallborhydrid containing cookies or granules can in the present. Procedures are applied.

As a starting material for the present polymerization process can also ethylene-containing gases, the hydrogen and hydrocarbons, such as those in the Refinery gases are included, so z. B. Methane., Ethane, Propane etc. contain, be used. However, it is advisable to use an ethylene as the starting material. that is as pure and focused as humanly possible.

It is useful to keep the catalysts in contact with oxygen. Keep carbonic acid, water or sulfur compounds to a minimum or to be avoided entirely.

The common use of a polymerization temperature between about 220 and 260 ° C and a liquid hydrocarbon, e.g. B. from benzene, xylene. Decalin (Dekahydronaphtha.Iin) or Methyldeka, lin, as a reaction medium for the purpose of production of ethylene polymers with specific viscosities (. 1f) on average between about 10,000 and 30,000 in continuous operation at relatively long-running unique. Throughputs and pure catalysts is appropriate.

The contact time or throughput rate in the polymerization process taking into account the other variables in this process, the catalysts, the particular type of product desired and that of a given experiment or passing over this catalyst to the desired extent of ethylene conversion set. In general, this variable can easily be determined in order to The desired results were achieved. When you consider the ethylene Uninterrupted flow of raw materials to and from the catalysts lie the suitable hourly flow rates usually between, about 0.1 and 10, preferably about 0.5 and 5, preferably about 2 volumes of ethylene solution per hour! Volume catalyst. An aromatic hydrocarbon is usually used as the reaction medium, z. B. benzene, 1ylene or tetralin (tetrahydronaphthalene), or a cycloaliphatic Hydrocarbon, e.g. B. decalin. (Decahydronaphthalene). The amount of ethylene in such Solutions can be between about 2 and 50, preferably 2 and 10, or for example vary between 5 and 10 percent by weight.

It was observed that when the ethylene concentration fell in the liquid reaction medium below about 2 weight percent the molecular weight and the melt viscosity of the polymeric products drop sharply. The speed the ethylene polymerization decreases with increasing concentration of ethylene in the liquid reaction medium to. The rate of ethylene polymerization below However, formation of high molecular weight, normally solid polymers is preferred not in such a way that these polymers are produced in large quantities. which their solubility in then liquid. Reaction medium, which is usually 5 to 7 percent by weight, under the reaction conditions, regardless of the amounts of polymeric products, which are also adsorbed by the catalyst. Though ethylene concentrations in, the liquid reaction medium of over 10 percent by weight can be used, but solutions of the ethyl alcohol of more than 5 to 10% in the reaction medium very viscous and difficult to handle. and a substantial split in the solid Octal oxide catalyst particles or fragments can enter. which entail has that the catalyst with the solution of the polymerization products in fine \ 'crtcilung passes over, causing considerable catalyst loss in the reaction vessel.

licini rudimentary procedures are operating times between i / - and about 10 hours, usually between 1 and about 4 hours, using the autoclave is charged with ethylene to the same extent as the pressure due to conversion of the ethylene al; fii1lt.

The (ic-weight ratio of solvent to catalyst can be in In the case of flow systems in the range of from about 5 to about 2000 or even higher, preferably between about 50 and 1000. The use of high proportions of solvents to catalyst created by the presence of a reactive metal borohydride can be made possible in the reaction zone is to achieve high polymerizate yields very important.

Ethylene, propylene or their mixtures can be in the gas phase and in Absence of a liquid reaction medium in the presence of the reactive metal borohydrides and the metal oxides are polymerized. To complete the process of the desired polymerization reaction you can then use the solid catalyst z. B. by Treat extraction with suitable solvents to remove solid polymerization products from it to win. In the interest of increased olefin conversion rates and uninterrupted Obtaining solid products from the catalyst, it is recommended that the conversion of ethylene in the presence of a suitable liquid reaction medium. The liquid reaction medium can also be used to add the olefin the catalyst by preparing a solution of the olefin in the liquid reaction medium to bring in touch.

There can be different groups of hydrocarbons or their Mixtures made under the polymerization conditions of the present process liquid and, practically inert, can be used. From the aromatic series Hydrocarbons, especially the aromatics with a ring, are: Benzene, Toluene, kylenes, mesitylene and xylene-p-cymene genes. Tetrahydronaphthalene can also be used can be applied. Finally, aromatic hydrocarbons can be used, to which ethylbenzene, isopropylbenzene, n-propyl: enzene, sec-butylbenzene, tert-butylbenzene, Ethyl toluene. Ethylxylenes, Hemimellitol, Pseudocumene, Prehnitol, Isodurol, Diethylbenzenes, Isoamylbenzene. Suitable aromatic hydrocarbon fractions can by selective extraction of aromatic naphthas, from hydroforming as Distillate or bottoms obtained from the fractions of the fission processes, etc. will.

Certain alkylnaphthalenes can also be used, which are listed under the present polymerization conditions are liquid, e.g. B. 1-methylnaphthalene, 2-isopropylnaphthalene: lin, 1-n-amylnaphthalene or fractions arising in technology, which contain these hydrocarbons.

In the present process, certain groups of aliphatic Hydrocarbons are used as liquid reaction media. So are different Saturated hydrocarbons (alkanes and cycloalkanes) are suitable, which are listed under the Polymerisa._ tion conditions are liquid. Either pure alkanes or Cycloa.lkane can be used or technically accessible mixtures freed from catalyst poisons can be used. So are z. B. Stra.ight-r-un-Benzine or Kerosene, the alkanes and Cvcloa.lkane contain. In particular, liquid or liquefied alkanes can be used, e.g. B. n-Pentasi, n-hexane, 2,3-diniethylbutane, n-octane, isooctane (2,2,4-tri methylpentane), ri-decane, n-dodecane, cyclohexane .. methylcyclohexane, dimethylcyclopentane, ethylcyclohexane, Decalin (decahydronaphthalene), illethyl decaline. Dimethyldekalin_ be applied can also be used as the liquid reaction medium liquid olefins such. B. n-hexanes, cyclohexene, 1-octene, hexadecenes.

The normally solid polymerization products that are on the catalyst surface be retained, or the grease-like ethylene polymers can to a certain extent act like a liquefied reaction medium themselves; it is but most expedient, in this case, as mentioned, the viscosity to give reducing hydrocarbon to the reaction zone.

The liquid reaction medium should be treated with acid, e.g. B. with anhydrous toluenesulfonic acid, Sulfuric acid:, or by equivalent l ') actions, e.g. B. finite aluminum halides or other Frie.del-Crafts catalysts, Maleic anhydride, Ca.lciuin, calcium hydride, sodium or others. Alkali metals, Alkali hydrides, lithium aluminum hydride, hydrogen and hydrogenation catalysts, Filtration through a column of copper grains or Group VIII metals, etc. or can be freed from catalyst poisons by a combination of such treatments.

The Xvlole were refluxed with a mixture of 1-1o0 3-A1203 catalyst and Li A1 H4 (50 ccm Xvlol-1 g catalyst-0.2 g Li A1 H4) Purified at atmospheric pressure and subsequent distillation of the xylenes. One more More effective cleaning of the solvent can be achieved by heating to about 225 to 250 ° C can be achieved with either sodium and hydrogen or NaH in a pressure vessel.

The temperature during. of the ethylene circulation process can easily with the help of the large liquid mass with relatively high heat capacity in the reaction zone can be adjusted. The liquid reaction medium can be exchanged by heat be cooled inside or outside the reaction zone. However, it should be noted., that in some cases the solvent may be present as a gas phase.

If as a solvent z. B. Nylole! can be applied under low alkylation of the reaction conditions; by ethylene. take place. Propylene is an even stronger alkylating agent than ethylene. If therefore If propylene is present in the feed, it is advisable to use a non-alkylating agent Solvents, e.g. B. Dekaliri ,, to use. The alkylate (alkylation product) is in the present. Process with the fat removed, it can, from it through fractionated Distillation. separated off and optionally returned to the polymerization zone will.

The drawing explains a method according to which the invention can be carried out. Man; directs the olefinic feed, e.g. B. ethylene or an ethylene-propylene geniisch, by the compressor 10, in which the pressure is at a suitable level, e.g. B. between 35 and 140 a: t, is brought, and from. there in the chamber 11, which with a suitable. Reducing agents, e.g. B. metallic copper of 150 ° C, is charged, and then into the chamber 12, which is filled with a dehydrating agent, for. B. adsorptive aluminum oxide, anhydrous calcium sulfate, silica gel or an equivalent desiccant is provided. The dried charge material is passed from the chamber 12 into the chamber 13, in which it is freed from carbonic acid. The chamber 13 is filled with a suitable reagent, e.g. B. with sodium hydroxide deposited on asbestos or with any other effective. Provide carbonic acid absorbing agents. After leaving the chamber 13, the load can optionally be dried further. The so purified feed usually contains less than 50 parts per million oxygen and has a dew point below -45 ° C. The purified feed is then passed into an absorber 14 where it meets solvent in countercurrent. This solvent or liquid reaction medium can be directed into the absorber by means of the pump 15 through the valve 16 and the heat exchanger 17, in which the feed is brought to a suitable absorption temperature, usually between about 15 and 35 ° C will. It can also be higher. or lower (temperatures may be used. Circulating solvent from line 61 can also be passed into the absorber, or it can be used as the only vacuum. 7 percent by weight ethylene, and from there through the valve line 18 for final cleaning into the chamber 19 a1. This chamber can contain an active metal or 3′-metal hydride, e.g. Alkaline earth metal, an alkali hydride or an alkaline earth hydride. It is best filled with calcium hydride. This chamber 19 is brought to temperatures between about, 100 and 280 ° C. If the charge is clean enough, the chamber 19 can through not shown in the drawing indicated lines are bypassed and the charge introduced directly into the reaction vessel 25.

From the chamber 19, the ethylene and the solvent are in the Line 20 and from there passed through the pump 21 into the heater 22, in which they on the z. B. between. The polymerization temperature is 200 and 275 ° C to be brought. From the heater 22 the feed passes through line 23 and from there through line 24 into the lower part of the reaction chamber 25. Although a large number of suitable reaction vessels can be used, here becomes a special one Autoclave is used, which is inobere by appropriately attached baffle plates26 and is divided into lower chamber sections. In the lower part of the reaction vessel All that is needed is a stirrer 27. There are suitable Pradl plates 28 on the walls of the autoclave appropriate. The stirrer is capable of between 20 and. To make 1000 revolutions per minute. It is usually operated at 650 revolutions. From this arrangement it can be seen that the catalyst, the reactive metal borohydride and the olefinic material and the liquid reaction medium in the lower part of the reaction vessel 25 in are mixed together to a high degree. The reaction vessel 25 can start with the metal oxide from group VI a, which acts as a catalyst, and the metal borohydride, z. B. Li B H4, charged through a hopper or corresponding devices during the reaction, additional amounts of metal oxide catalyst and metal barhydrides, if necessary, added in a suitable manner at intervals ..

If necessary, a. Part of the predried solvent through the valve line 29 and the heater 30 are sent, in which it is on a Temperature between about 150 and 300 ° C is heated to from there in one with the Praljplatten: 32, the stirrer 33 and an inlet 34 for the alkali metal Contact chamber 31 to reach. In this Kon.taktkaminer 31 is an intimate dispersion of the alkali metal in the solvent and made from the above proportionately quiet zone of the contact chamber 31 withdrawn through the valve line 35 into the line 24, to be pressed into the reaction vessel 25 by the pump 36. A. other very useful method of cleaning the solvent in the contact chamber 31 consists in "this solvent finite an alkali: lihydride, usually NaH, and a catalyst consisting of 10 percent by weight Mo 03 on γ-alumina to clean, with about 3 to 10 weight percent applied n metal oxide per Part by weight of alkali hydride applies, at an idle temperature between about 135 and 270 ° C and a throughput rate between, about 1 / E and 10 volumes Solution / hour A'olunien catalyst.

In your reaction vessel 25, the polymerization of Ätiiyleul or the copolymerization of ethylene with other monooletins, e.g. B. propylene causes suitable temperatures and pressures. The usual concentration of ethylene in the solvent. which enters the reaction vessel is usually included 10 percent by weight, while the liquid flowing out of the reaction vessel is usually a 2 to 5 weight percent solution of solid polymer in the solvent represents. If you want to produce a homopolymer of ethylene. the one Having melt viscosity from 2 # 105 to about 5-105 poises are the best Temperatures between about 230 and 275 ° C. The reaction time can be between about. Vary 10 and 100 minutes.

Of course, one can instead of the one reaction vessel Use a number of reaction vessels connected either in parallel or in series are. If reaction vessels are turned around in series there are variations in temperature and pressure, in olefin concentration, in solvent and in the catalyst concentration possible, so that both the average molecular weight and the molecular weight range of the product as well as the degree of conversion can be set even more precisely in each stage. When using a Number of interconnected reaction vessels with the. associated secondary lines and valves you can also turn off each reaction vessel from the system, if it needs to be cleaned or repaired.

The upper part of the reaction vessel 25 represents a quiet settling zone in which fine catalyst particles and metal borohydride from the solution of the polymeric product are in then. Separate the reaction solvent and, under the influence of gravity, return to the lower, moving part of the reaction vessel. The relatively clear solution of the reaction products in the solvent is withdrawn from the upper part of the reaction vessel 25 through the line 37 and the equalizing valve 38, in which the pressure drops to about 1 to about 17.5 atm. able. The mixture is passed horizontally through valve 38 into a separator (e.g. cyclone type) 39 in which a temperature of at least 150 ° C is maintained. From this separator 39 is a gas containing a substantial amount of poison-free ethylene, through the. Valve line 40 withdrawn. Hot solvent can be introduced into the separator 39 through line 51. to prevent the polymer from depositing on the walls of the separator. According to a preferred mode of operation, the clear liquid flowing out of the reaction vessel 25 is pressurized through the valve 38 to the vapor pressure of the solvent, while the temperature in the separator 39 remains at about 200.degree. In this procedure, practically all of the ethylene and a substantial part of the benzene are removed from the drain (from the reaction vessel, 25) and can be returned to the reaction vessel (by means of a pump not included, drawing, tT, eitungeii-rrii't) will. The relatively concentrated polymer solution can be treated as described below.

The solution of the polymer in the solvent is released from the separator 39 withdrawn through the valve line 41 into the filter 42., In which all fine Catalyst particles that may have reached this point are separated and replaced by the Valve line 43 can be withdrawn. Optionally, the Polynierisatlösung can Effect of an ultrasonic vibrator, through which the agglomeration the very fine catalyst particles is effected. so that this is more easily filtered off can be.

The solution of the polymeric product is collected from the filter 42 by conduit 44 withdrawn into the cooler 45, in which its temperature is reduced to about 20 to 90 ° C is set, whereupon it passes through line 46 to the filter 47. The solid polymer product is removed from filter 47 at 48 and the solvent or Reaction medium withdrawn through line 49, from where a portion through the valve line 50 taken out of the system and another part through valve line 51, the Pump 52 and the heater 53 enters the separator 39, while the rest through Valve line 54 flows into fractionator 55.

The precipitation of the polymer from the solution in line 44 can through Addition of nonsolvents such as low-boiling hydrocarbons, e.g. B. Propane, alcohols, ketones (acetone), etc., are introduced. The one distant at 48 polymeric product of the process can be subjected to various treatments to prepare it for the transformation into the technical end product .. So it can be treated in various ways, including the enclosed solvent remove; it can be pressed into tape-like structures, dried, etc.

In the fractionation device 55, the solvent or liquid Reaction medium evaporated and discharged as top product through line 56, wherein a part can be taken out of the system through the l'eritilleitung 57, although it is more advantageous to pass the liquid through the valve line 58 into the cooler 59 is performed, in which their temperature is brought to about 20 to 80 ° C, of where it gets into the pump 60. The pump 60 presses the liquid through the Valve line 61 and the heat exchanger 17 in the absorber 14, one solution of fresh ethylene source materials. for the polymerization process. A portion of the solution is also supplied by the pump 60, through the valve line 62 in FIG the upper part of the absorber 63 is pressed. Circulating gases out again the separator 39 and line 40 are through the valve line 64 and the Compressor 65 passed via line 66 into the lower part of absorber 63, in which ethylene is selectively absorbed in the solvent in order to this U'eise to produce a solution whose concentration of ethylene is between about 2 and 10 percent by weight which are discharged from your absorber 63 through the valve line 67 into the line 20 from where it enters the reaction vessel 25. The unabsorbed Gases are taken out of the absorber 63 through the valve line 68.

Liquid reaction products with boiling points above the boiling range of the reaction medium can be obtained from the fractionation device 55 and the method be discharged through valve line 69, preferably send one but it through the valve line 70 into a second fractionation device 71. A By-product of the present polymerization process produced in a relatively small amount when using an alkylatable aromatic hydrocarbon, e.g. B. from Xylo1, the solvent used is an aromatic hydrocarbon which can be alkylated by reaction of this formed with ethylene (or propylene if this was part of the feed) Alkylate. These alkylated aromatic hydrocarbons are stored in tower 71 evaporated and fractionated and. taken out through line 72. It is common expediently, at least part of the alkylate through valve line 73 into the line 41 returned to it as a diluent and solvent in the filter 42 use. The remainder of the alkylate can be drained from the system through valve line 74 or it can be returned to the dcii circuit to be part of the liquid reaction medium in the reaction device 25 to use.

Relatively small amounts of low molecular weight grease-like, Ethylene polymers are produced in the polymerization processes in question Invention: they are extracted as a soil fraction from your tower 71 through the valve line 75 deducted.

In another work process following the filtration of the fine catalyst particles in your filter 42 is the dilute solution of Äthylenpolyinerisate in, the solvent, e.g. B. Benzene, introduced into a tower of hot water or contains a mixture of water and steam, the temperature being so high that the solvent (or an azeotropic mixture of solvent and water) rapidly distilled from the solution and an aqueous sludge of the solid polymer finite about 1 to 5 weight percent polymer is formed. This aqueous Polymerisa.tschlamm can be concentrated in the usual way, to a content of about Bring 10 to 15 percent by weight of polymer, which is then centrifuged to obtain a polymer that contains only a small amount of water and can be dried thoroughly in any conventional device. That with this one rapid distillation overhead solvent can be condensed, separated from a layer of liquid water, distilled for further drying and. finally with the help of desiccants, e.g. B. silica rule or alumina gel, thoroughly dried. before putting it into storage or the polymerisation zone returns.

Another process is the, Polvmerisat: solution in one aromatic solvent from which the fine catalyst particles have been removed are sprayed to dryness.

When discussing the following examples, the significant effect becomes the reactive metal borohydrides as activators of the polymerization due to. following>; considerations apparently. In the. Try taking that without an activator Use of a molybdenum oxide pre-reduced from 8 percent by weight to i, -aluminium oxide existing catalyst and a ratio of pure Xv lolen to catalyst (ccm / g) of 5 were performed per gram of catalyst at 230 ° C and. an initial ethylene pressure of 70 at 0.5 g of solid ethylene polymers obtained, ethylene was repeatedly pressed into the reaction vessel until no further one Äthvlen could be absorbed more of the reaction mixture. It couldn't be solid Polymer produced when dried and de-carbonated ethylene. at a partial pressure of about 46 at with 2.0 g of a tungsten oxide-zirconium oxide catalyst (which had been pre-reduced with hydrogen at 450 ° C and atmospheric pressure) 250 ° C for 21 hours.

The following examples are intended to illustrate the invention. The reaction vessel in each case was a pressure vessel with a capacity of 250 ccm and a magnetically operated stirrer. A constant stream of nitrogen displaced the air from the reaction vessel during charging. Residual air was purged from the autoclave with the aid of hydrogen before the reaction started. Example 1 1 g of catalyst composed of 8 percent by weight molybdenum on γ-aluminum oxide after pre-reduction with hydrogen at 480 ° C. was used. The catalyst was applied in the form of a filter cake which had been brought to a mesh size of 58 to 1050 per square cm. The reaction vessel was further charged with 0.2 g of lithium borohydride and 100 cc of purified xylenes as solvents. The contents of the vessel were heated to 249 ° C. under low hydrogen pressure, then ethylene was introduced to a partial pressure of about 58 atm while the contents were stirred. Ethylene is then introduced into the reaction vessel from time to time in order to maintain the initial partial pressure. The reaction was over after 345 minutes. 9.3 g of a polymer were obtained which could be converted into a tough, flexible film; The polymer had a specific viscosity (17 rel - 1 - 105) of the 24,600th a melt viscosity from 1.4 to 106 poises, and a density at 24 ° C of 0.963. In addition, 0.40 g of a fat-like polymer and 1.0 g of alkylated Xvlole were formed.

When this experiment was repeated, the lithium borohydride was replaced by the same amount by weight of sodium borohydride at 247 ° C., an ethylene partial pressure of about 56at and no solid polymer was obtained within 12 hours; 1.46 g of a fat-like polymer were obtained and 2.33 grams of alkylated xylenes. According to the Pauling scale, sodium has an electronegativity of 0.9, and N a B H4 only reacts very slowly with water at normal temperatures (0 to 25 ° C). Example 2 In a repetition of Example 1, the lithium borohydride was replaced by magnesium borohydride in order to produce a solid ethylene polymer. The process and the resulting product corresponded completely to Example 1. Example 3 In a repetition of Example 1, the lithium borohydride was replaced by aluminum borohydride in order to produce a solid ethylene polymer. The process and the resulting product corresponded completely to Example 1. Example 4 In the reaction vessel were introduced 2.0 g of a catalyst which consisted of 20 percent by weight Woffrainoxvd - on Zirl; oniumoxvd and had a mesh size of 130 per square cm (it was at 450 C and atmospheric pressure with hydrogen), 0.5g lithium borohydride and 100ccin isooctane. The contents of the reaction vessel were heated to 250 ° C. with stirring under a weak hydrogen pressure; to this, ethylene was added up to a partial pressure of about 50 atm, which was maintained for 17 hours. The result was 2.36 g of solid; polymer, 0, 74 g of fat-like polymer and 1.3 g of alkylation product Example 5 The reaction vessel is charged with 2.0 g of the wolfran oxide-zirconium oxide catalyst from Example 4, 0.5 g of lithium chloride and 100 cc of decalin which has been treated with silica gel The contents are heated with stirring to 225 ° C. under a weak hydrogen pressure and then charged with ethylene up to a partial pressure of about 66.5 atm. The reaction runs for 20 hours, during which time ethylene is added as required to maintain the initial partial pressure. This gave 8.9 g of a solid ethylene polymer which was able to form a tough and flexible film, a melt viscosity of 1.8-105 Poises and a density (at 24 ° C) of 0.9608. An alkylate (alkylation product) of decalin was obtained as a by-product in an amount of 1.0 g. Example 6 Example 5 was repeated, except that lithium borohydride was replaced by magnesium borohydride. A tough, flexible ethylene polymer was produced. Example 7 Example 6 was repeated, except that lithium borohydride was replaced by aluminum borohydride. A tough, flexible ethylene polymer was produced.

In the examples above, "specific viscosity" means - (relative Viscosity - 1) - 105 and "relative viscosity" the ratio of the outflow time of a Solution of 0.125 g of polymer in 100 ccm of purified vials at 110 ° C. from a Viscometer at the outflow time of 100 ccm of pure lylenes at 110 ° C. The melt viscosity becomes i e n e> and K 1 e m m according to the procedure of 1). j. Appl. Phys., 17th p. 458 to 471 (1946), determined.

The polymers produced by the process according to the invention can be subjected to the various post-treatments. They can be pressed, mechanically rolled, processed into films, cast or processed into sponges or latices will. I? S can give them antioxidants, stabilizers. Fillers, extenders, Plasticizers, pigments. Insecticides and fungicides are incorporated. The polyethylene can be used as pulling agents or binders.

The polymers according to the invention, especially those with high specific Viscosities can be mixed with the lower molecular weight polyethylenes, around this the stiffness or flexibility or other desired properties of the to lend inventive products. In a similar way, those according to the Processes of the invention produced solid, resinous products in each desired quantitative ratio with hydrocarbon oils, waxes, such as. B. Paraffin waxes and Petro-Tatuni, with ester waxes, with high molecular weight polybutylenes and with others organic matter verini,; cht to be. Small between 0.01 and 1 ° / o that of yours present process produced various Ätlivlenpolvmerisate lying - Amounts can be dissolved or dispersed in lubricating oils to increase the viscosity index increase and decrease oil consumption when these oils are added can be used in engines.

Those generated by the present process. a molecular weight of 50,000 or more 1'olyinerisate can be used in small amounts to the essential Increasing the viscosity of easily flowing hydrocarbon oils and as a gelling agent be used for such oils.

The polymers according to the invention can have various chemical properties Be subjected to reactions; nian can halogenate them and dehalogenate them again. z. B. sulfohalogenate by treatment with stilfuryl chloride, also sulfonate.

Claims (6)

PArix-r "srRt`Cirs: 1. Process for the polymerization of ethylene or Propylene alone or of ethylene in a mixture with propylene or other monoolefins to products with molecular weights of at least 300 at elevated temperature in Presence of an oxidic catalytic converter, characterized in that the Starting material at temperatures between 75 and 325 ° C in the presence of a borohydride of a metal whose electronegativity according to Pauling's scale is at least 1 and its borohydride compound violently with water at 25 ° C with formation of hydrogen, and at least one oxide of a Group VI metal a of the periodic table polymerized or non-polymerized. 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, has been partially reduced beforehand. 4. The method according to claim 1, 2 or 3, characterized in that the catalytically active metal oxide used is applied to a difficult to reducible metal oxide as a carrier. 5. Procedure according to claim 1, characterized. that <las borohydride lithium, magnesium or Aluminum chloride is. 6. The method according to any one of claims 1 to 5, characterized in that the polymerization or copolymerization is carried out at pressures between about 1 and 1000 kg / cm =. Considered publications: German Patent Specifications No. 813 214, 836 711; German patent applications Z 1119 IVc / 39c (published on 28 B. 1952), Z 771 IVc / 39c (published on 29 May 1952), B 7335 IVc / 39c (1 @ - announced on 19 June 1952); British Patent No. 682,420; U.S. Patent No. 2,212,155; Franz K rczi 1, Kurzes Handbuch der Polymerisierungstechnik, Vol. 1, S.213.