METHOD OF SYNTHESIS OF CHLOROPRENE

摘要

FIELD: organic chemistry and chemical technology. SUBSTANCE: chloroprene is synthesized by dehydrochlorination of 3,4-dichlorobutene-1 with an alkali aqueous solution in the presence of catalyst - quaternary ammonium compound followed by separation of dehydrochlorination product for an organic phase containing chloroprene and catalyst and an aqueous phase containing practically all by-side product - chloride salt. Organic phase is treated with hydroxy-acid that interacts with catalyst and the separate phase is formed. The latter is separated from an organic phase that contains chloroprene. Chloroprene has the decreased content of ammonium catalyst. The catalyst used: compound where nitrogen atom is bound with four radicals by covalent bonds; radicals are C6-C20-alkyl or alkenyl, aralkyl. One of radicals is alkyl, alkenyl or aralkyl having hydroxyl or simple ether group at beta--position to nitrogen atom. Hydroxy acid is taken from inorganic acids, polymeric resins containing by-side inorganic acid groups. Hydroxy acid occurs in phase that does not mix with the indicated organic phase and the separate phase containing quaternary ammonium compound and hydroxy acid is formed. Interaction with hydroxy acid is carried out at 0-60 C. Hydroxy acid is used as aqueous solutions and taken from phosphoric, sulfuric, nitric, perchloric, chromic, carbonic, alkyl-, arylsulfoacids, molybdenic, selenic, sulfurous, tungsten, hypophosphoric, nitrous and periodic acid. Hydroxy acid: polymeric resins containing by-side groups of sulfoacid or phosphinic acid. Amount of added hydroxy acid is 2-10 eq/1 eq quaternary ammonium catalyst. Method involves recovery of at least some amount of quaternary ammonium catalyst isolated at the stage of separation to the stage of dehydrochlorination, or part of the isolated quaternary ammonium catalyst is added to the stage of dehydrochlorination without its separation from hydroxy acid. EFFECT: decreased content of catalyst in chloroprene synthesized. 11 cl, 4 dwg, 3 tbl, 25 ext