| 摘要 |
The present invention relates to a process for obtaining a polyisoprene having a high cis-1,4 linkage content, from a steam-cracked C5 naphtha fraction enriched with isoprene. The process of the present invention comprises reacting a steam-cracked C5 naphtha fraction in the presence of a catalytic system, wherein the C5 fraction is enriched with isoprene such that the mass fraction of isoprene in said enriched fraction lies within a range of from 30% to 95%, and the catalytic system is based on at least (a) a conjugated diene monomer, (b) an organic phosphoric acid salt of one or more rare earth metals, (c) an alkylating agent consisting of an alkylaluminum of the formula AlR3 or HAlR2, and (d) a halogen donor consisting of an alkylaluminum halide, said salt being suspended in at least one inert saturated hydrocarbon solvent of aliphatic or alicyclic type which is included in said catalytic system, and the molar ratio of alkylating agent:rare earth salt is in a range of from 1 to 5. |
