Production of dihalomethanes containing fluorine and azeotropes of dihalomethanes containing chlorine with HF

摘要

A process for producing difluoromethane is disclosed which includes the step of contacting a gaseous mixture containing CH2Cl2 and hydrogen fluoride with a catalyst containing a catalytically effective amount of trivalent chromium supported on a carbon having an ash content of less than 0.5 percent by weight, at a temperature of from about 180 ° C. to about 375° C. The catalyst and temperature conditions of this process allow the concurrent reaction CCl3CF3 with HF to form CCl2FCF3. CH2ClF and unreacted CH2Cl2, each of which may be recovered as an azeotrope with HF, may be recycled.