Diimide reduction of cis-1,4-polyisoprene with p-toluenesulphonylhydrazide

Abstract

The hydrogenation of cis-1,4-polyisoprene with diimide generated in situ from p-toluenesulphonylhydrazide (TSH), was investigated under various conditions. In aromatic solvents at 100–140°C, the rate of hydrogenation was increased with increase in concentration of polyisoprene and of TSH. Part of the polymer was depolymerized and cyclized during the reaction. Increasing the hydrogenation tended to decrease the rate of sulphur vulcanization, of the compounded rubber and the physical properties of vulcanizates were poor. The reaction of polyisoprene rubber with TSH, was also carried out in a solid state at 140°C for 20–60 min. It was found that by using a large amount of TSH hydrogenation and cyclization of rubber occurred. The quantity of TSH used as a blowing agent, for rubber in the manufacture of sponge rubber, i.e. 5–10 phr, did not cause hydrogenation.