| 摘要 |
A rubber polybutadiene containing at least 85% of cis 1, 4-addition is obtained by polymerizing 1, 3-butadiene using a catalyst system comprising (a) an organometallic hydride RnMHm where R is alkyl, cycloalkyl, aryl, cycloalkylalkyl, aralkyl, alkylcycloalkyl, arylcycloalkyl, alkaryl or cycloalkyarly radical containing up to and including 20 carbon atoms, M is aluminium, gallium, indium or thallium and "n" and "m" are each 1 or 2 and "m" +n" equals 3 and (b) a component selected from (i) titanium tetraiodide, (ii) titanium tetraiodide plus titanium tetrachloride and (iii) iodine and a titanium halide TiXy where X is chlorine or bromine and y is 2, 3 or 4. The mol ratio of the organometallic hydride to the total molar quantities of the second catalyst component must be greater than 1. When the second component is titanium tetraiodide, the mol ratio of RnMHm compound to each titanium halide is preferably in the range 2:1 to 50:1 and the mole ratio of titanium tetrachloride to titanium tetraiodide is preferably in the range 0.5:1 to 5:1. When the second component is a mixture of iodine and a titanium halide, the mole ratio of the titanium halide to iodine is preferably in the range of 0.25:1 to 10:1 and the mole ratio of the organometallic hydride to the titanium halide is preferably in the range 2:1 to 20:1. The polymerization may be carried out in a diluent and a batch or continuous process may be used. Long lists of organometallic compounds and specific catalyst systems are given but those used in the examlpes are (i) diisobutyl aluminium hydride, titanium tetrachloride and tetraiodide, (2) diisobutylaluminium hydride and titanium tetraiodide, (3) diisobutylaluminium hydride, iodine and titanium tetrachloride, (4) ethylaluminium dihydride and titanium tetraiodide, (5) phenylgallium dihydride, titanium tetrachloride and titanium tetraiodide, (6) dibutylindium hydride, titanium tetrachloride and iodine and (7) dipentylthalliun hydride, titanium tetrachloride and titanium tetraiodide.
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