Polymer supported metal complexes as catalysts for oxidation of thiosalts by molecular oxygen: I. Poly(4-vinyl pyridine)—Cu(II) complex
Abstract A copper(II) complex of lightly cross-linked poly(4-vinyl pyridine) has been prepared and used as a catalyst for oxidation of thiosalts by molecular oxygen at ambient temperatures. This polymeric complex has been found to catalyse oxidation of thiosulphate, trithionate and tetrathionate to sulphate. A detailed study of the kinetics of oxidation of thiosulphate by molecular oxygen in the presence of this catalyst revealed that at 96.7 kPa total pressure and 30°C, resistance to the reaction using 106 – 149 μm-size particles is approximately equally divided between extraparticle mass transfer and the chemical activity of the complex. The mechanism of oxidation of thiosulphate has been suggested based on product distribution and kinetics. The rate of oxidation is not significantly affected by the activity of the reaction medium down to a pH of 2.0, but falls markedly as pH is reduced further.