Catalytic wet oxidation of thiocyanate with homogeneous copper(II) sulphate catalyst

The wet oxidation of thiocyanate has been investigated in a semi-batch reactor at temperatures between 423 and 473 K and pressures between 6.1 × 103 and 1.0 × 104 kPa in the presence of copper(II) sulphate as catalyst. The effects of copper concentration, initial thiocyanate concentration, pressure and temperature on the reaction rate were analyzed and the main products of reaction were identified. A kinetic model for the Cu-catalyzed reaction is here proposed, including temperature, oxygen concentration, and the reduction of Cu2+ to Cu+ that gives an accurate prediction of the oxidation process under the assayed conditions. A mechanistic model based on the formation of a transition complex between a copper cation and two thiocyanate anions has been proposed for the catalytic wet oxidation.