Reductive dechlorination of carbon tetrachloride by cobalamin(II) in the presence of dithiothreitol: mechanistic study, effect of redox potential and pH

Article abstract of DOI:10.1021/es00051a010

A mechanistic study of the reductive dechlorination of carbon tetrachloride by vitamin B₁₂ (cyanocobalamin) in the presence of dithiothreitol was conducted as a function of redox potential and pH. The solution redox potential decreased both with an increase in the total concentration of dithiothreitol present and with an increase in pH. The pseudo-first-order rate constant of carbon tetrachloride disappearance increased with decreasing redox potential. The predominant cobalt species present under the reaction conditions was cobalamin(II) (vitamin B_12r), as confirmed by spectrophotometric analysis, suggesting a one-electron reduction of vitamin B₁₂ and the involvement of two vitamin B₁₂ molecules per reacting carbon tetrachloride molecule. -from Authors