Stability of Catalysts for the Oxidative Chlorination of Methane

The effects on the stability of catalysts for the oxidative chlorination of methane due to evaporation of the active component (copper chloride) of the catalyst are studied. The volatility of copper chloride is shown to depend mainly on the catalyst composition and temperature. At a moderate 350 degrees C in the reactor, the evaporation of copper chlorides after 5 h is 0.45% on a catalyst containing copper and potassium chloride and 0.72% on a catalyst containing lanthanum chloride. The stability of catalyst operation can be effectively maintained not only by decreasing the volatility of copper chloride, but also by feeding hydrochloric acid with dissolved copper chloride isolated from the reaction gas of methane oxychlorination at the outlet of the reactor (for the removal of reaction heat and the recycling of unconverted hydrogen chloride) back into the reactor.