JPS605675B

PURPOSE:To synthesize diester of dicarboxylic acid electrolytically with high current efficiency by limiting the ratio between the monoester of dicarboxylic acid and supporting electrolyte in an electrolyte and controlling the quantity of the electricity to be conducted according to said ratio. CONSTITUTION:In the stage of electrolyziing monoester of dicarboxylic acid in the presence of a supporting electrolyte such as NaOH, the ratio between the monoester of dicarboxylic acid and supporting electrolyte in the electrolyte is set at 0.1-0.4, and according to said rate, the quantity of the electricity to be supplied is controlled. Before the formation of impurities initiates on decreasing of an increase in the yield of the diester of dicarboxylic acid, the electrolysis is ceased, and after the formed diester of dicarboxylic acid is recovered, the consumed monoester of dicarboxylic acid is replenished and again the electrolysis is executed. By the repetition of such operations, the diester of dicarboxylic acid is electrolytically synthesized with high current efficiency and the formation of byproducts is suppressed.