DE1232747B - Process for the production of polymers of ethylenically unsaturated compounds - Google Patents

Description

Process for the production of ethylenically unsaturated polymers Compounds It is known that ethylenically unsaturated compounds are among Use of radical-forming especially peroxide catalysts for high molecular weight Can polymerize plastics. Such procedures are widely used under Use of the most varied of ethylenically unsaturated compounds carried out. A major advantage of this process is the insensitivity of the catalysts against water. However, this method gives products in which the monomers are not incorporated in a sterically uniform manner, d. i.e., stereospecific polymerizations cannot be carried out using the known radical-forming catalysts will.

It is also known that ethylenically unsaturated compounds, especially ethylenically unsaturated hydrocarbons, using ionic ones Catalysts such as Lewis acids and so-called Ziegler catalysts, d. H. particularly Mixtures of organoaluminum compounds and halides of titanium to form high molecular weight Products can polymerize. This can be done especially when using Ziegler catalysts Obtain products in which the monomers are incorporated in a sterically uniform manner. Examples this is the polymerization of propylene or butadiene using Ziegler catalysts for isotactic polypropylene or cis-polybutadiene.

A disadvantage of the ionic catalysts of the type mentioned is, for. B. their great sensitivity to water and air. The polymerization process, at which ionic catalysts are used must therefore use very pure monomers and optionally solvents carried out with the exclusion of air and moisture will. This requires a considerable technical effort.

Finally, it is known that ethylenically unsaturated compounds are used using organic complex compounds of subgroup IV and VIII. Group of the Periodic Table of the Elements, in particular of chelate complex compounds of these elements, e.g. B. zirconium acetylacetonate and cobalt acetylacetonate as catalysts can polymerize to high molecular weight products. These catalysts are against Air and water are relatively insensitive and in many cases are stereospecific Effect on. Another advantage of these known catalysts can be seen in this that it is possible with their help to polymerize such monomers, which are not cleaned extremely well. The space-time yield of polymers leaves but in the known processes in which metal chelate compounds of the above Kind to be used as polymerization catalysts, as with an induction period occurs during the polymerization.

These known polymerization processes are therefore used Advantage of reaction accelerators, e.g. B. organic halogen compounds, too.

It has now been found that polymers by polymerizing ethylenically unsaturated compounds in the presence of organic complex compounds of the metals of subgroup IV and / or group VIII of the Periodic Table of the Elements can be produced with particular advantage if the organic complex compounds used are cyclopentadienyl-azo- Complex compounds of the general formula is used in which R, R 'and R "represent optionally substituted hydrocarbon radicals or R' represents a cyano, carbalkoxy or alkoxy radical and Me represents a metal of subgroup IV or group VIII of the Periodic Table of the Elements of the type mentioned are; z-complexes, which are obtained, for example, by reacting the corresponding dicyclopentadienyl complexes with azo compounds at elevated temperature according to the method described by JP K 1 eimann et al in Am. Chem. Soc., 85 (1963), p 1544, specified process for the preparation of cyclopentadienyl- [o- (phenyl-azo) -phenyl] -nickel can be prepared. , Butyl, methyl, fl-cyanoethyl or a cyano-tert-butyl radical, R 'for a phenyl, tolyl, cyclohexyl, benzyl, p-methoxyphenyl, o-methoxybenzyl, methyl, sither -, tert-butyl, cyano, carbethoxy, methoxy or ethoxy radical and in which R "represents an aliphatic hydrocarbon radical having 1 to 4 carbon atoms, e.g. B. a methyl, ethyl or tert-butyl group. As central atoms Me come for the complex compounds z. B. those of cobalt, nickel, iron, rhodium, ruthenium, platinum, palladium, titanium and zirconium in question, and cobalt, nickel, rhodium and titanium atoms are preferred as central atoms. Examples of suitable cyclopentadienyl-azo complex compounds are cyclopentadienyl - [- o - (phenyl-azo> -phenyl] -nickel, methylcyclopentadienyl - [-o - (methoxyphenyl-azo) -cyano-tert-butyl cobalt, cyclopentadienyl - [-0- (cyanophenyl-azo) -tolyl] -titanium.

The complex compounds of the type mentioned can be used in the process be used alone or in a mixture with one another. In general, one sets the polymerization batch between 0.0001 and 5, preferably between 0.01 to 1 percent by weight, based on the amount of ethylenically unsaturated compounds to. The complex compounds of the type mentioned can also be used in the new process together with cocatalysts, e.g. B. Halides of metals of III. to VIII. Group of the periodic table, such as cobalt chloride, chromium (II) -, chromium (III) chloride, titanium ( III), titanium (IV) chloride, aluminum chloride, complex compounds of titanium trichloride and aluminum chloride of the general formula 3 TiCh - AlCl3 and / or with organometallic Compounds such as aluminum triethyl, diethyl aluminum chloride, ethyl aluminum dichloride, Aluminum sesquichloride, trimethyl aluminum, mercury diphenyl, phenyl magnesium bromide, Diethylberrylium and triphenylaluminum can be used. As cocatalysts There are also organic halogen compounds such as carbon tetrachloride and chloroform and butyl chloride, cycloaliphatic hydrocarbons such as cyclohexadiene, cyclooctadiene and cyclooctatetraene, and amines such as piperidine, triethylamine, diethylenetriamine and pyridine, in question. The ratio of the amount of cocatalysts to complex compounds the formula mentioned can be varied within wide limits. It is in general between 1:10 and 10: 1.

The process is of particular importance for the polymerization of Ethylenically unsaturated hydrocarbons, such as monoolefins with 2 to 4 carbon atoms, z. B. ethylene, propylene and butylene (l), of 1,3-dienes, such as butadiene (1,3), isoprene, 2-phenylbutadiene (1,3), 2,3-dimethylbutadiene (1,3), and vinyl aromatic compounds, such as styrene and methyl styrene, e.g. B. a-methyl styrene and p-methyl styrene. Ethylenic Unsaturated hydrocarbons of the type mentioned can be used in the process by themselves or polymerized in a mixture with one another will. In addition, the new polymerization process also with advantage for the production of copolymers from ethylenically unsaturated Hydrocarbons of the type mentioned and other ethylenically unsaturated compounds can be applied. As copolymerization components come, for. B. halogenated Styrenes, such as o-chlorostyrene, styrenesulfonic acid, ethylenically unsaturated carboxylic acids and their derivatives, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, acrylonitrile, Methacrylonitrile, maleic anhydride, acrylamide, methacrylamide, methyl acrylate, ethyl, n-butyl and tert-butyl esters, methacrylic acid methyl and tert-butyl esters, Maleindimethyl, diethyl and din-butyl ester, fumaric acid dimethyl and di-tert-butyl ester, Vinylidene halides. such as vinylidene chloride and vinyl chloride, vinyl esters such as vinyl acetate, Vinyl propionate and vinyl benzoate, vinyl ethers, such as vinyl methyl ether and vinyl n-butyl ether, Vinyl ketones. such as methyl vinyl ketone and isopropenyl vinyl ketone, as well as ethylenically unsaturated heterocyclic compounds such as vinyl pyrrolidone, vinyl caprolactam, vinyl imidazole and vinyl carbazole. In the case of the copolymers, the proportion of ethylenic unsaturated hydrocarbons generally at least 30 percent by weight, based on the total monomers.

The complex compounds of the general formula mentioned are in usually soluble in organic solvents and also in the monomers.

They can be handled safely in air.

Also, it is often not necessary to use extremely pure monomers and auxiliaries to use. If the complex compounds are used without the addition of metal alkyls, you can also polymerize in the presence of water and small amounts of atmospheric oxygen.

The complex compounds of the general formula mentioned are already Catalytically effective in extremely low concentrations. If you use small amounts the initiators, it is usually not necessary to use them after the polymerization to remove from the polymers. In some cases it is possible to use the catalysts on carriers such as activated carbon, carbon black, aluminum oxide, silica gel and aluminum silicates, to raise.

With the new process, monomers can be copolymerized, those with initiators customary up to now are only partially or not at all copolymerized could become; z. B. can be ethylene with vinyl ethers, olefins, such as propylene, butene- (l), and butadiene with acrylic acid or acrylamide without difficulty copolymerize.

Some of the polymers have a sterically ordered structure. Polyethylene made by the process of the invention is largely crystalline Structure and density above 0.94. In the polymerization of dienes, the 1,4 linkage is favored. The new process has particular importance for the production of homo and Copolymers of 1-olefins.

The molecular weights of the polymers obtained can depending on den.Polymerisationsbedingungen be varied in a wide range. The polymerization can generally be carried out between -50 and 250.degree. Ethylene is preferred at 20 to 160 ° C, butadiene and isoprene preferably between -20 and polymerized at 150 ° C.

You can work at any pressure, if necessary you can Use pressures up to about 4000 atmospheres and more.

With the catalysts to be used according to the invention, the Monomers are homo- and co-polymerized in bulk. But you can too To polymerize, dissolve the monomers in inert liquids, emulsify them or suspend. Liquids suitable for this purpose are, for example, saturated ones aliphatic, cycloaliphatic and aromatic hydrocarbons, such as n-pentane, n-hexane, isohexane, n-heptane, n-octane, isooctane, cyclohexane, methylcyclohexane, benzene, Toluene, o-, m- and p-xylene, ethylbenzene, cumene, isopropylbenzene, tetrahydronaphthalene and decahydronaphthalene, as well as halogen derivatives of such hydrocarbons as Chloroform, methylene chloride, ethylene chloride, chlorobenzene and bromobenzene. Farther ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, dioxane, glycol dimethyl ether are suitable and phenyl methyl ether, also alcohols and ketones, such as methanol, ethanol, propanol, Isopropanol, butanols, cyclohexanols, benzyl alcohol and acetone, as well as water.

The process can be carried out continuously or batchwise will. The complex compounds can in the continuous polymerization in Mix with the monomers or a liquid of the type mentioned in the reaction vessel be introduced.

The parts mentioned in the examples are parts by weight. The K values were determined according to H. F i k e n t -schwer, Cellulose-Chemie, 13 (1932), p. 58.

Example 1 1000 parts of 1 part cyclohexane are placed in a pressure vessel Cyclopentadienyl- [o- (phenyl-azo) -phenyl] -cobalt and 1 part of aluminum triethyl added. Ethylene is injected up to a pressure of 150 atmospheres.

The reaction mixture is then increased to 135 bis within 3 hours 140'C and kept at this temperature until the pressure in the reaction vessel remains constant. There are 320 parts of polyethylene with a density of 0.942 and a K value 88.5 (measured in 0.50 / above solution in toluene) were obtained.

If you work without the addition of aluminum triethyl, there is a pressure of 830 atm necessary to get the same yield. The density is then 0.936 and the K value 56.

Example 2 A mixture of 100 parts of 1,3-butadiene, 100 parts of benzene, 1 part cydopentadienyl- [o- (phenyl-azo) -phenyl] -nickel (I) and 1 part titanium (IV) chloride is heated to 100-C for 10 hours. There are 45 parts of polybutadiene of the K value 91 (measured in Iolig solution in benzene). The vinyl group fraction of the Polymer is 80/0, the proportion with 1,4-cis structure 34 and the proportion with 1,4-trans structure 580/0.

Used instead of titanium (IV) chloride as a catalyst component a mixture of 0.5 part of aluminum chloride and 0.5 part of cobalt (II) chloride, see above a polybutadiene is obtained, the proportion of which with a 1,4-cis structure is 560/0. Of the K value of the gel-free-soluble products (measured in 1 0/0 solution in benzene) is 87.

The corresponding rhodium complex can also be used in place of the nickel complex be used.

Products are then obtained with a somewhat higher proportion of 1,4-trans structure.

Example 3 A mixture of 50 parts of isoprene, 50 parts of styrene, 100 Parts of benzene, 1 part of cyclopentadienyl - [- o- (phenyl-azo) -phenyl] -nickel- (I) and 1 Part of titanium tetrachloride is heated to 100 ° C. for 10 hours.

After the usual work-up, 78 parts of a copolymer are obtained, which has a K value of 78 (measured in 1 0 / above solution in benzene).

Used with 1 part of cyclopentadienyl- [-o- (phenyl-azo) -phenylj-titanium worked instead of the nickel complex, 83 parts of a copolymer are obtained with a K value of 93. The 1,2 content of this polymer is 5% in contrast to 120/0 1.2 parts if the nickel complex is used.

Claims (1)

Claim: Process for the production of polymers by polymerizing ethylenically unsaturated compounds in the presence of organic complex compounds of the metals of subgroup IV and / or group VIII of the Periodic Table of the Elements, characterized in that the organic complex compounds used are cyclopentadienyl - azo complexes of the general formula used, in which R, R 'and R "stand for optionally substituted hydrocarbon radicals or R' for a cyano, carbalkoxy or alkoxy radical and Me for a metal of subgroup IV or group VIII of the periodic table.