Denki Kagaku Kogyo Kabushiki Kaisha

Denki Kagaku Kogyo Kabushiki Kaisha, Chuo-kenkyusho

Takao Iwasaki

Hideki Matsumura

Seiichi Watanabe

Takashi Kadowaki

Higashi Ito

Koichi Abe

Junji Hirano

Chloroprene is produced by reacting 3,4-dichlorobutene-1 in an aqueous solution of an alkali metal hydroxide in the presence of at least one of furfuryl alcohol and tetrahydrofurfuryl alcohol preferably at 20.degree. to 70.degree. C.

Process for producing chloroprene

Chloroprene is produced by reacting 3,4-dichlorobutene-1 with a base in the presence of thiodiphenyl amine and 2,6-di-tertiarybutyl-p-cresol and preventing clogging of the equipment. 3,4-Dichlorobutene-1 is produced by an isomerization of the reaction mixture obtained by a chlorination of excess of butadiene wherein higher boiling compounds are separated before a separation of the unreacted butadiene.

In production of chloroprene by dehydrochlorinating 3,4-dichlorobutene-1 in the presence of an aqueous solution of alkali, the mixture of 3,4-dichlorobutene-1 and the aqueous solution of alkali is heated at 85.degree. to 100.degree. C to evaporate a mixture consisting mainly of the resulting chloroprene, unreacted 3,4-dichlorobutene-1 and water rapidly, the evaporated mixture is taken out from the reaction system without subjecting to a distillation and totally condensed, the condensed reaction mixture is separated into an aqueous phase and an organic phase and then the organic phase is fractionally distilled to separate chloroprene from 3,4-dichlorobutene-1. Prior to subjecting the organic phase to the fractional distillation, if the organic phase is previously subjected to a drying means and the water content in the organic phase is reduced to a proper degree, it is possible to avoid formation of polymer of the resulting chloroprene and corrosion of the distillation column.

Growing community of inventors

Ohmi, Japan

Takao Iwasaki