Chemical effects of anodic contact glow discharge electrolysis Formation of amino acid

Abstract

In Contact Glow Discharge Electrolysis (CGDE), a plasma is sustained by d.c. glow discharges between an electrode and the electrolyte around it. The chemical results of CGDE are significantly non faradaic. With the anodic plasma in an aqueous electrolyte, non-faradaic results originate mainly from break-up of liquid water molecules near the plasma | anolyte interface by sufficiently energized H 2 O + gas ions coming out of the plasma into H and OH in yields as high as 13 moles per mol electron of electricity. The radical generating potentiality of anodic CGDE in high local concentration in liquid phase has been explored as a tool for synthesizing amino acids from ammoniacal solution of carboxylates. The results show that amino acids such as glycine from ammoniacal acetate electrolyte and α-alanine from ammoniacal propionate electrolyte are formed in yields exceeding the Faraday law value. The formation of amino acid by anodic CGDE has been explained by radical scavenging action of ammonia and carboxylates on H and OH radicals and by mutual interaction between NH 2 and RC HCOO - radicals formed. The present technique requires 0.1- 0.2 kcal for production of 10 -5 mol of glycine as compared to 24 kcal by spark discharge and 50 kcal by X-ray for glycine production from constituents of reducing atmosphere.