Electrochemical synthesis of thiocarbamates

The possibility of indirect and direct electrosyntheses of thiocarbamates i s studied. The indirect synthesis is based on producing monochloramines by the chlorination of an aqueous solution containing an amine and sodium chlo ride on a dimensionally stable anode (DSA) in diaphragm electrolysis and a subsequent interaction of monochloramines with potassium xanthate. Optimum synthesis conditions are found ensuring a current efficiency for thiocarbam ates of 43-60%. These are: c(amine) = 0. 17-2 M, c(NaCl) = 4 M,j(a) = 20-30 A dm(-2) electrolysis temperature 10 degrees C, the chloramine : potassium xanthate : amine molar ratio of 1 : 1.1 : 2, and the temperature of the re action between chloramine and potassium xanthate of 8 degrees C. The direct synthesis of thiocarbamates is realized in diaphragm electrolysis when oxi dizing an aqueous solution containing an amine, potassium xanthate, and sod ium chloride on DSA. With the electrosynthesis of ethyl ester of methylthio carbamic acid as an example, conditions are found that allow one to obtain a target product with a current efficiency of about 44%. However, the direc t synthesis is accompanied by the destruction of the anode material.