| 摘要 |
1,182,935. Polymerization catalyst for isoprene. MICHELIN & CIE (Compagnie Generale des Etabs Michelin). 15 May, 1967 [16 May, 1966; 10 Feb., 1967], No. 22512/67. Heading C3P. A polymerization system for isoprene comprises a mixture of (a) a hydrocarbon solution of an ether of the general formula R-0-R<SP>1</SP> in which R and R<SP>1</SP> are aromatic organic groups which may be linked together otherwise than through the oxygen atom, and a tetravalent titanium salt, and in which the ether/Ti ratio is greater than 1; and (b) a solution of an organo-aluminium compound in a hydrocarbon, or an aliphatic, cycloaliphatic, or aromatic carbide. The ether may be diphenyl ether or dibenzofurane. The activity of the catalyst system may be increased by including therein a small quantity of isoprene or butadiene either in the pure state or as a hydrocarbon solution having a diene/Ti molar ratio greater than 1. The preferred aluminium compound is triisobutyl aluminium. Specified titanium compounds are the tetrachloride and tetrabromide. The preferred hydrocarbon is heptane, and this also functions as the polymerization medium. The catalyst may be " aged." The recovered polyisoprene has a high cis-1,4 content.
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