Patent ID: 6635790
Filing Date: 2003-10-21
Classification: C07C,Y02P

Abstract:
A continuous process for the manufacture of difluoromethane (F32) from methylene chloride (F30) and hydrogen fluoride (HF) in the gas phase in a reactor in the presence of a fluorination catalyst, comprising:carrying out a reaction in the presence of chlorine, wherein the gas flow exiting from the reactor is subjected to a distillation to separate, at the top, a flow containing virtually all the hydrochloric acid and at least 90% of the F32 produced by the reaction, and at the bottom, a flow containing at least 90% of the unconverted reactants F30, chlorofluoromethane (F31) and HF present in the gas flow exiting from the reactor, and the flow recovered at the distillation bottom is recycled directly to the reactor, wherein the HF/organics molar ratio at the reaction inlet is between 1 and 10.