Kinetics and mechanism of oxidation of hypophosphite by hexacyanoferrate(III) ion in alkaline solution

Abstract

Hypophosphite is oxidised to phosphite by hexacyanoferrate(III) in alkaline solution according to equation (i). [H₂PO₂]^–+ 2[Fe(CN)₆]^3–+ OH^–→ H₃PO₃+ 2[Fe(CN)₆]^4–(i) The rate law at 55.7 °C is (ii) where k′=(2.80 ± 0.08)× 10^–4 l² mol^–2 s^–1 at I= 4.7M. The ionic-strength –d[Fe(CN)₆^3–]/dt=k′[Fe(CN)₆^3–][H₂PO₂^–][OH^–](ii) dependence and entropy of activation show that ion-pair species are more reactive in this reaction.