Patent ID: 6605193
Filing Date: 2003-08-12
Classification: C07C

Abstract:
A method of isolating difluoromethane from a crude mixture containing HCl and an azeotropic mixture of difluoromethane and HF, which method comprises the steps of (A) feeding to a column a stream of said crude mixture and a stream of a compound having a boiling point higher than that of difluoromethane, (B) distilling in said column the streams from step (A) in order to generate a column overhead of HCl and a column bottoms whose bubble point and composition varies with the amount of heat applied to it, (C) removing HF from the column bottoms of step (B) by washing, and (D) distilling the remaining mixture from step (C) to separate difluoromethane from any compound having a boiling point higher than that of difluoromethane without the need to isolate any azeotropic mixture of difluoromethane and HF.