METHOD OF SYNTHESIS OF COUPLED DIOLEFIN HYDROGENATED COPOLYMERS Russian patent published in 1996 - IPC

FIELD: chemical technology. SUBSTANCE: method of synthesis of coupled diolefins synthesized by anionic polymerization of coupled diolefin with organolithium polymerization initiating agent in suitable solvent involves the formation of "living polymer" followed by selective hydrogenization of unsaturated double bonds in coupled diolefin links by contact of polymer with hydrogen in the presence of bis-(cyclopentadienyl)-titanium compound (Ti). Before hydrogenization the "living polymer" is terminated by hydrogen addition. Termination is carried out at contact and intensive stirring of hydrogen with polymerizing solvent at the end of polymerization reaction. Hydrogen feeding is carried out by bubbling. Hydrogenization is carried out at t = 0-120 C, under pressure 0.069-83 bars, Ti concentration = 0.01-20 mM per 100 g polymer at contact time for 15-1440 min. Hydrogenization stage is carried out in the presence of lithium hydride (Li) formed in situ at the stage of "living polymer" termination. Ratio Li : Ti at hydrogenization process is, at least, 2:1. Li hydride is obtained in situ by addition or Li-organic compound and hydrogen to polymer solution before hydrogenization catalyst addition. Hydrogenization is carried out at t = 60-90 C, under pressure 6.9-13.8 bars, at concentration Ti = 0.04-1.0 mM per 100 g polymer, at molar ratio Li : Ti = 6:1, at contact time 30-360 min. Molar ratio Li : Ti is, at least, 10:1. Li-organic inhibitor of polymerization is sec.-butyllithium. Ti-compound is bis-(cyclopentadienyl)-titanium dichloride. Coupled diolefin is taken from the group involving butadiene and isoprene. Diolefin is copolymerized with vinyl-substituted aromatic hydrocarbon. Diolefin is copolymerized with monomer taken from the group involving styrene and its derivatives. Diolefin copolymer is a block-polymer containing, at least, one block-polymer of coupled dienes and, at least, one block of styrene or its derivatives. At least 50% unsaturated bonds in coupled diene links and, at least, 95% unsaturated bonds in coupled diene were subjected for hydrogenization. EFFECT: improved method of synthesis. 17 cl, 2 tbl