PROCESS FOR THE PREPARATION OF 1,2 SYNDIOTACTIC POLYBUTADIENE IN THE PRESENCE OF A CATALYTIC SYSTEM COMPRISING A COBALT COMPLEX WITH A PHOSPHINE LIGAND

摘要

Process for the preparation of 1,2 syndiotactic polybutadiene comprising polymerizing 1,3-butadiene in the presence of a catalytic system comprising: at least one cobalt complex with a phosphine ligand having general formula (I): wherein: R₁, R₂ and R₃, mutually identical or different, are selected from branched C4-C20 alkyl groups, preferably C₄-C₁₅, C₆-C₃₀ cycloalkyl groups, preferably Ce-Cis, said cycloalkyl groups being substituted, C₆-C₃₀ aryl groups, preferably Ce-Cis, optionally substituted; provided that at least two of R₁, R₂ and R₃ are selected from C₆-C₃₀ aryl groups, preferably Ce-Cis, optionally substituted; X₁ and X₂, mutually identical or different, represent a halogen atom such as, for example, chlorine, bromine, iodine; at least one aluminoxane having general formula (II): (R₄)₂-AI-0-[-AI(R₅)-0-]_m-AI-(R₆)₂ (II) wherein R₄, R₅ and R₆, mutually identical or different, represent a hydrogen atom, or a halogen atom such as, for example, chlorine, bromine, iodine, fluorine; or are selected from linear or branched C₁-C₂₀ alkyl groups, cycloalkyl groups, aryl groups, said groups being optionally substituted with one or more silicon or germanium atoms; and m is an integer ranging from 0 to 1000; said process being carried out at a temperature ranging from 0° C. to +60° C., preferably ranging from 0° C. to +30° C.;