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 polybutadienecomprising polymerizing 1,3-butadiene in the presence of a catalytic systemcomprising: at least one cobalt complex with a phosphine ligand having generalformula (I) : wherein: R1, R2 and R3, mutually identical or different, areselected from branched C4-C20 alkyl groups, preferably C4-C15, C6-C30cycloalkylgroups, preferably Ce-Cis, said cycloalkyl groups being substituted,C6-C30 aryl groups, preferably Ce-Cis, optionally substituted; provided thatatleast two of R1, R2 and R3 are selected from C6-C30 aryl groups, preferablyCe-Cis, optionally substituted; X1 and X2, mutually identical or different,representa halogen atom such as, for example, chlorine, bromine, iodine; at leastone aluminoxane having general formula (II) :(R6)2 (II) wherein R4, R5 and R6, mutually identical or different, represent ahydrogen 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 withone or more silicon or germanium atoms; and m is an integer ranging from 0to 1000; said process being carried out at a temperature ranging from0°C to+60°C, preferably ranging from 0°C to +30°C.