Catalytic reduction of hydrogen ions in solution in the presence of vitamin B12s and buffer acids

Abstract

The presence of buffer ions like borate. phosphate, carbonate, sulphite, ammonium, etc., particularly those having acidic hydrogen atoms, enhances the evolution of hydrogen from solutions of vitamin B_12s. The rate of evolution is proportional to the concentrations of the buffer acid, B_12s and H⁺. In addition to the above ions, highly polarisable ions like cyanide and sulphide are very effective. Controlled potential electrolysis has been used as the analytical method and has led to a quantitative description of the rate of hydrogen evolution. The efficiency of the catalysts falls in the order CN^– > HS^– > HSO₃^– H₂PO₄^– > H₃BO₃ > pentane-2,4-dione > phenol NH₄⁺ > HCO₃^– > H₂O. A mechanism for the catalysis is proposed.