Reaction kinetics of oxychlorination of carbon monoxide to phosgene based on copper(II) chloride

The reaction parameters of oxychlorination of carbon monoxide to phosgene, reaction temperature, reaction time and CO pressure were optimized. The online FT-IR technique is successfully employed for the first time to determine the composition of the product effluent. The formation rate of phosgene increases with the reaction temperature. The maximum formation rate of phosgene is 1.2 × 10^-3 mmol mL^-1 min^-1 at 375 °C. At the same time, the decomposition rate of phosgene increases with the reaction temperature, too. A higher pressure of CO can lead to a faster formation rate and a higher yield of phosgene. The catalyst is more stable at 300 °C than at 345 or 375 °C. At 415 °C the catalyst is nearly completely deactivated. The optimized reaction conditions are 300 °C, 6 min and 5 bar CO, where the cumulative yield of phosgene can reach up to 86.5%. The by-product HCl comes from the hydrolysis of phosgene or the surface reaction of CuCl₂ and the residual water or the hydroxyl groups on the silica surface. CO₂ is formed from the hydrolysis of phosgene.