| 摘要 |
Polymers of butadiene in which at least 75% of the monomeric units have a cis-1,4 configuration, are made by polymerizing butadiene in the presence of a catalyst formed by mixing a p lithium hydrocarbon, and titanium tetraiodide or titanium trichloromonoiodide. The ratio of the lithium hydrocarbon to the titanium compound is preferably between 1:1 to 3:1 on a molar basis. The lithium hydrocarbon may be formed by reacting metallic lithium with olefinically unsaturated compounds such as butadiene, isoprene, styrene, or a substituted styrene. In the case of butadiene the lithium hydrocarbon may be formed in situ in the polymerizable medium. The polymerization is preferably effected in a hydrocarbon medium. The lithium hydrocarbon may be methyl, ethyl, butyl, amyl, dodecyl lithium, methylene dilithium, ethylene dilithium, hexamethylene dilithium, allyl or methallyl lithium, phenyl, tolyl, or naphthyl lithium, or 1,4-dilithium benzene. The polymers are recovered from the polymerizate using conventional techuniques, e.g. ethanol treatment.
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