Process for the manufacture of pentafluoroethane
AssigneeE. I. Du Pont de Nemours and Company
InventorsVinci M. Felix, William H. Gumprecht, Barry A. Mahler
Life of this patent
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Abstract
An improved process for the manufacture of CF.sub.3 CHF.sub.2 by contacting CF.sub.3 CHCl.sub.2 or CF.sub.3 CHClF with HF in the presence of a Cr.sub.2 O.sub.3 catalyst prepared by pyrolysis of ammonium dichromate, the reaction being conducted under controlled conditions whereby the production of CF.sub.3 CHF.sub.2 is maximized, and the formation of chloropentafluoroethane (CF.sub.3 CClF.sub.2) and other perhalo derivatives is minimized. The subject hydrogen-containing compound is useful as a blowing agent, propellant, refrigerant, fire extinguishing agent, or sterilant carrier gas.
Claims14
A process for the preparation of CF.sub.3 CHF.sub.2 comprising:
- (a) contacting HF with at least one reactant selected from the group consisting of CF.sub.3 CHCl.sub.2 and CF.sub.3 CHClF in the gas phase in the presence of a catalyst comprising Cr.sub.2 O.sub.3 at a mole ratio, feed rate of reactant per weight of catalyst, temperature and pressure and for a time effective to form a gas stream containing CF.sub.3 CHCl.sub.2 as the predominant component and thereafter,
- (b) separating and recovering CF.sub.3 CHF.sub.2 from the product stream.
A process for producing pentafluoroethane comprising the steps of:
- (a) pyrolyzing a material comprising ammonium dichromate to obtain Cr.sub.2 O.sub.3 ;
- (b) contacting hydrogen fluoride with at least one member from the group consisting of CF.sub.3 CHCl.sub.2 and CF.sub.3 CHClF while in the presence of said Cr.sub.2 O.sub.3, wherein at least a portion of said at least one member is converted to pentafluoroethane without substantial formation of perhalogenated by-products, and;
- (c) recovering the pentafluoroethane.
A process for preparing CF.sub.3 CHF.sub.2 comprising the steps of:
- (a) contacting hydrogen fluoride with at least one member selected from the group consisting of CF.sub.3 CHCl.sub.2 and CF.sub.3 CHClF, while in the presence of Cr.sub.2 O.sub.3 to form a product comprising CF.sub.3 CHF.sub.2, wherein said product is substantially free of CF.sub.3 CClF.sub.2, and
- (b) recovering said product.
Dependencies are inferred from the claim text.