GB1311354A - Electrolytic hydrodimerization of acrylonitrile - Google Patents

Abstract

1311354 Electrolytic hydrodimerization process ASANI KASEI KOGYO KK 8 May 1970 [8 May 1969] 22408/70 Heading C2C [Also in Division C7] In producing adiponitrile by electrolytic hydrodimerization using an aqueous catholyte comprising acrylonitrile and a conductive supporting salt, such as quaternary (e.g. tetraalkyl) ammonium salt, or a halide, nitrate or phosphate, the conductive supporting salt is recovered from the catholyte by contacting at least a part of it with a cation exchange resin, e.g. of the strongly acidic sulphonate type or weakly acidic carboxylate type. Acrylonitrile and/or adiponitrile may be recovered from the catholyte by solvent extraction, decantation or evaporation, before or after the catholyte is contacted with the cation exchange resin. E.g. the catholyte may be an emulsion of an aqueous phase containing 2% acrylonitrile, 9% adiponitrile, 8% tetraethylammonium sulphate, 0À05% emulsifier polyvinyl alcohol, balance water, and an oil phase containing 17% acrylonitrile, 75% adiponitrile, 5% water and 3% organic byproducts comprising propionitrile. As shown, the catholyte emulsion recirculated through a tank 3 is passed consecutively in portions to acrylonitrile stripper 4, where the acrylonitrile recovered is recycled to the tank 3 and condensed water is discharged through end 6, then allowed to stand in decanter 7, where it is separated into aqueous and oil phases, and the separated aqueous phase only, e.g. passing through heat exchanger 9 and further (storage) decanter 10 and water addition tank 12, contacts the cation exchange resin in column 13; the conductive supporting salt thus regenerated is stored in tank 16 and continuously introduced into the tank 3. The catholyte is separated by a cation exchange diaphragm 1-3 from the anolyte, e.g. H 2 SO 4 solution, which is recirculated through tank 2. The cathode may be of Pb alloy containing 6% Sb, the anode of a similar alloy additionally containing 0À7% Ag.