The oxidation of the hypophosphite ion by water, catalysed by metal–phosphorus and metal–boron alloys

Abstract

The hydrolysis of the hypophosphite ion occurs according to equation (i) and is catalysed by nickel–phosphorus, H₂PO₂^–+ H₂O [graphic omitted] → H₂PO₃^–+ H₂(i) cobalt–phosphorus, and nickel–boron alloys. The stoicheiometry and the kinetic behaviour have been examined by measuring the hydrogen evolved in the catalysed hydrolysis at 98·7 °C. Further information concerning the reaction mechanism has been obtained by carrying out the reaction in D₂O or D₂O–H₂O mixtures. The reaction can be followed by ¹H n.m.r. measurements of the concentrations of the species H₂PO₂^– and H₂PO₃^–. The deuterium content of the gas evolved has also been studied. A reaction mechanism is proposed involving simultaneous reactions in which the hypophosphite molecule exchanges either one or both phosphorus-bound hydrogen atoms with the solvent.