Synthesis of L-Cysteine and L-Cysteic Acid by Paired Electrolysis Method

L-Cysteine and L-cysteic acid were synthesized by paired eletrolysis method. A high purity over 98% and high yield over 90% of both products were gained. When current density was 7 A/dm^2 and concentration of L-cysteine was 0.6 mol/dm^3, the highest current efficiency of anode and cathode was achieved. Total current efficiency was over 180%. The cyclic voltammetry behaviors of hydrobromic acid and cystine showed that a typical EC reaction took place in the anodic cell. The anode reaction and successive chemical reaction accelerated each other to get a high speed and current efficiency.