KINETICS AND MECHANISM OF THE OXIDATION OF PHOSPHINIC, PHENYLPHOSPHINIC AND PHOSPHORUS-ACIDS BY BROMINE

Oxidation of lower oxyacids of phosphorus by aqueous bromine has been studied in the [H+] range 0.001-5.0 mol dm-2. The reaction is first order with respect to bromine and the oxyacid. Molecular bromine has been postulated as the reactive oxdising species. Oxidation of deuteriated phosphinic and phosphorous acids exhibited substantial kinetic isotope effect. A study of [H+] variation showed the oxy-anion is oxidised much more rapidly than the parent acid. It is proposed that the 'inactive' tautomer of the oxyacid participates in the oxidation process. A suitable mechanism has been suggested.