GB969826A - Polymers of dienes and their production - Google Patents

Abstract

Homopolymers of the formula: <FORM:0969826/C3/1> wherein n is an integer having a value of at least 50, R is an alkyl radical of up to 3 carbon atoms or a n-hexyl, cyclohexyl, alkoxy, or phenyl radical, and the valences shown as unsatisfied are satisfied by attachment to other recurring groups or to hydrogen atoms, or by formation of double bonds between adjacent carbon atoms having unsatisfied valences, are made by polymerizing in an organic liquid solvent, a conjugated diene of the formula CH2=CH-CR=CH2, where R has the meaning set out above, in the presence of a catalyst formed from a compound of a polyvalent metallic element of atomic number 22-29 inclusive which contains directly attached to the metal, at least one halogen, oxygen, hydrocarbon, or -o-hydrocarbon substituent, and a halogen-containing organo-metallic aluminium compound. The aluminium compound has the formula R1aAlXb where R1 is an alkyl radical of 1 to 8 carbon atoms or an aryl radical, X is a halogen atom, a has a value of 2.5 to 0.5 and b has a value from 0.5 to 2.5. The diene may be isoprene, 2-ethyl-1, 3-butadiene, 2-propyl-1, 3-butadiene, 2-n-hexyl-1, 3-butadiene, 2-cyclohexyl-1, 3-butadiene, 2-ethoxy-1, 3-butadiene, or 2-phenyl-1, 3-butadiene. The polyvalent compound may be VOCl3, TiCl4, TiOCl2, (C3H7O)2TiCl2, C4H9OTiCl3, VCl4, FeBr3, CrCl3, MmBr2, CoCl3, NiCl2, Cu2Cl2, or VCl2. The aluminium compound may be methyl aluminium sesquichloride or sesquibromide, diethyl aluminium chloride, isobutyl aluminium dibromide, ethyl aluminium dichloride, dipropyl, aluminium bromide, butyl aluminium dibromide, diethyl aluminium fluoride, ethyl aluminium difluoride and diethyl aluminium iodide. In a modification the aluminium compound may be replaced by another metal of Group III above hydrogen in the electromotive series. The polymerization may be chlorobenzene, tetrachloroethylene, chlorotoluene, cyclohexane, heptane, or benzene.