Process for the manufacture of pentafluoroethane
AssigneeE. I. Du Pont de Nemours and Company
InventorsMario J. Nappa, V. N. Mallikarjuna Rao, William R. Williams
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Abstract
A process is disclosed for the preparation of pentafluoroethane from chlorotetrafluoroethane (the yield of pentafluoroethane is at least 50 mole percent based upon the amount of chlorofluoroethane reacted with HF) with particularly low levels of chlorofluoroethanes. The process involves providing sufficient pretreatment (where necessary) of a Cr.sub.2 O.sub.3 catalyst with at least one agent selected from the group consisting of CO, H.sub.2, H.sub.2 O and mixtures thereof in the gaseous state such that the total chlorofluoroethane content of said product stream is less than 1 mole percent. Certain high surface area catalysts may be used without such pretreatment.
Claims10
A process for producing pentafluoroethane, characterized by:
- contacting a feed mixture of (i) monohydrochlorofluoroethane feed comprising at least 80 mole percent chlorotetrafluoroethane and (ii) HF feed, wherein the mole ratio of HF to chlorotetrafluoroethane in the feed mixture is between about 1.5:1 and 10:1, in the vapor phase with a Cr.sub.2 O.sub.3 catalyst at a temperature between about 250.degree. C. and 400.degree. C. and for a contact time effective to form a vapor phase product stream containing pentafluoroethane, wherein the yield of pentafluoroethane is at least 50 mole percent based upon the amount of chlorotetrafluoroethane reacted;
- and
- providing sufficient pretreatment of the Cr.sub.2 O.sub.3 catalyst with at least one agent selected from the group consisting of CO, H.sub.2, H.sub.2 O and mixtures thereof in the gaseous state such that the total chlorofluoroethane content of said product stream is less than 1 mole percent.
Dependencies are inferred from the claim text.