Chlorine Production by HCl Oxidation in a Molten Chloride Salt Catalyst

A molten salt mixture containing 45 mol % KCl and 55 mol % CuCl2 was investigated as a catalyst for the reaction of HCl with O2 to produce Cl2. The HCl conversion for an HCl:O2 molar feed ratio of 1:2 at 450 °C and a total pressure of 1 atm was 80% at a residence time of less than 1 s in a lab scale bubble column reactor. The equilibrium conversion at this temperature and pressure is 84%. The catalyst system was found to remain stable throughout a continuous 24-h experiment. The use of a mixed transition metal/alkali metal molten salt catalyst for HCl oxidation reduces the volatility of supported chlorides and may avoid the mechanical stability limitations of solid catalysts caused by volume changes between the halide and the oxide.