E.i. Dupont De Nemours and Company

David A Glasscock

Michael Keane, Jr

Paul S Furmanek

Barry Asher Mahler

V N Mallikarjuna Rao

A process for producing difluoromethane is disclosed which includes the step of contacting a gaseous mixture containing CH,Cl,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 &deg; C. to about 375&deg; C. The catalyst and temperature conditions of this process allow the concurrent reaction CCl,CF,with HF to form CCl,FCF,. CH,ClF and unreacted CH,Cl,, each of which may be recovered as an azeotrope with HF, may be recycled.

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

A process for producing difluoromethane is disclosed which includes the step of contacting a gaseous mixture containing CH.sub.2 Cl.sub.2 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.degree. C. to about 375.degree. C. The catalyst and temperature conditions of this process allow the concurrent reaction CCl.sub.3 CF.sub.3 with HF to form CCl.sub.2 FCF.sub.3. CH.sub.2 ClF and unreacted CH.sub.2 Cl.sub.2, each of which may be recovered as an azeotrope with HF, may be recycled.

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Bear, DE, United States of America

David A Glasscock