GB895993A - Vinylation of mercaptans - Google Patents

Abstract

Vinyl sulphides are prepared by reacting a mercaptan with acetylene in the presence, as catalyst, of (1) an aqueous solution of a weakly basic salt having a hydrolysis constant from 10-2 to 10-7, the solution containing dissolved therein at least 0.01 mole of weakly basic salt per mole of mercaptan, (2) an aqueous solution of ammonia or a weakly basic amine having a dissociation constant from 10-3 to 10-8, the solution containing dissolved therein at least 0.01 mole of ammonia or amine per mole of mercaptan or (3) a water-swollen amine-based anion-exchange resin having a dissociation constant from 10-3 to 10-8. When a solution (1) or (2) is used, the amount of water present is preferably sufficient to result in formation of two phases in the product mixture. The reaction may be effected at temperatures from 100 DEG C.-180 DEG C. and under pressures of from atmospheric up to 500 p.s.i. Specified basic salts are sodium carbonate, trisodium phosphate, disodium hydrogen phosphate, sodium cyanide and sodium borate; specified amines include ethylamine, ethylene diamine, benzylamine, dimethylamine, triethylamine, dimethyl benzylamine, cyclohexylamine, morpholine, methyl diethanolamine and triethanolamine. The anion-exchange resins are preferably aminolyzed cross-linked acrylic-type copolymers and chloromethylated and aminated styrene/divinyl benzene copolymers and several are described. Examples describe the preparation of vinyl sulphides from inter alia, n-butyl mercaptan (yielding sometimes 1 : 2-bis-(butyl thio)-ethane as by-product), methyl mercaptan, 1 : 4-butane-dithiol, benzyl mercaptan, cyclohexyl mercaptan, phenoxyethyl mercaptan, tetrahydrofurfuryl mercaptan, thienyl methyl mercaptan, 2-mercapto benzothiazole, mercapto ethanol and mono-thio glycerol using aqueous solutions of NH3 or various of the above mentioned salts or amines or water-swollen anion exchangers of both the above named types. Reference is also made to the use of mercaptans containing amido groups. Specifications 427,903 and 28544/47 as laid open to public inspection under Section 91 of the Acts 1907-1942 are referred to.