Electrochemical synthesis of chromium carbonyl

Abstract

Carbonylation of chromium(III) complexes can be achieved by electrochemical reduction in anhydrous solvents saturated with CO under medium pressure. Yields up to 85% in Cr(CO)₆ can be obtained by carbonylation of CrCl₃(py)₃ in pyridine at 85 °C and ca. 60 atm pressure. Cathodic current efficiencies show that side reduction of pyridine also occurs; at low current densities stoicheiometric correlation between pyridine and chromium reductions is found, probably owing to the reduction of co-ordinated solvent.