GB702275A - Manufacture of glutaconic acid dinitrile - Google Patents

Abstract

The invention comprises 1-chloro-3-cyanopropene-1 which is obtained in the first stage of a preparation of glutonic acid dinitrile made by heating hydrogen cyanide in an aqueous medium at pH 2-7 with 1, 3-dichloropropene-1 in the presence of a cuprous salt as a catalyst and a hydrogen chloride acceptor, adding to the recovered 1-chloro-3-cyano-propene-1 catalytic amounts of a basic agent and of a weakly acid reacting agent or their reaction product selected from phenol, cresols, xylenols, phthalimide, benzene sulphonamide, benzene sulphonimide, aliphatic sulphinic acids, phenyl acetylene, thiophenol, thiocresols, thioxylenols and aliphatic mercaptans and heating hydrogen cyanide in an aqueous acid medium at pH 2-7 with the 1-chloro-3-cyano-propene-2 thus obtained in the presence of a cuprous salt as catalyst and a hydrogen chloride acceptor. Hydrogen cyanide may be supplied as an alkali metal or alkaline-earth metal cyanide. When free hydrogen cyanide is used pressure is preferably applied. The 1, 3-dichloropropene-1 may be obtained by chlorinating propene and crude reaction mixtures obtained via such chlorination or high or low boiling isomers may be used. Hydrogen chloride may be removed by chemical means or by means of a diaphragm by diffusion or by dialysis. The copper catalyst is most effective when the cuprous cyanide and halogen acid, preferably hydrochloric acid, and cuprous halide, preferably cuprous chloride, and hydrocyanic acid are in equilibrium. An excess of dichloropropene is advantageously present. Temperatures of 50-150, preferably 75-100 DEG C., are specified. The catalyst may be maintained in the cuprous form by the addition of metallic copper or by excluding oxygen. Preferably 2-5 per cent. of the basic and weakly acid agents based on the 1-chloro-3-cyano-propene-1 charged are used. The bases and weak acids are generally used in equivalent quantities. In examples (1) 1, 3-dichloropropene-1 and (2) high-boiling and (3) low-boiling isomers thereof are converted to the corresponding 1-chloro-3-cyano-propene-1 using cuprous chloride and aqueous acidic sodium cyanide, and 1-chloro-3-cyano-propene-1 is converted to the propene-2 with (4) sodium phenolate, (5) mixed phenol and sodium phenolate, (6) sodium phenolate in benzene, (7) aqueous sodium phenolate, (8) sodium benzene sulphonamide, (9) phenol and piperidine, (10) potassium phthalimide, (11) sodium phenyl acetylene, (12) phenol and calcium oxide, (13) sodium ethyl-sulphinate, (14) sodium hexane dithiol, (15) sodium 1-mercapto-hexanol-6 and (16) o-thiocresol and caustic soda, in (17) 1, 3-dichloropropene-1 is treated with aqueous acidic cuprous chloride and sodium cyanide to yield 1-chloro-3-propene-1 which on treatment with sodium phenolate yields 1-chloro-3-propene-2 which is converted to the dinitrile by treatment with aqueous cuprous chloride and sodium cyanide, (18) 1, 3-dichloropropene-1 is converted to 1-chloro-3-cyano-propene-1 as in (1) which is isomerized as in (4) and the dinitrile obtained as in (17), (19) 1, 3-dichloropropene-1 is converted to 1-chloro-3-cyano-propene-1 and 1-chloro-3-cyano-propene-2 by the methods of (1) and (4).