Showing papers in "Journal of The Chemical Society (resumed) in 1944"

43. Rubber, polyisoprenes, and allied compounds. Part VI. The mechanism of halogen-substitution reactions, and the additive halogenation of rubber and of dihydromyrcene

Abstract: The chlorination of cyclohexene by chlorine or by sulfuryl chloride (in the absence of a peroxide catalyst) yields substituted as well as additive chlorination products, and the former retain in full the original olefinic unsaturation, as indicated by iodine-value determination ; but whereas sulfuryl chloride forms only the additive dichloride and a monochloroolefin which is substituted exclusively in the 3-position, chlorine yields a mixture of saturated trichloro derivative (chloro-substituted addition product) and isomeric monochloroolefins (3- and 4-substituted), with some additive dichloride. No evidence of substitution at the ethylenic methine carbon atom has been obtained in the chlorination of cyclohexene, dihydromyrcene, and rubber by chlorine. The diminished unsaturation of the chloro-substitution products of the last two hydrocarbons is attributed to cyclization—a process which is complete in the case of rubber, but affects only a minor proportion of the molecules of dihydromyrcene. Th...