Process for preparing fluorinated aliphatic compounds

Abstract

A process is disclosed for the preparation of a fluorinated aliphatic olefin having the formula CH.sub.a F.sub.3-a --CH.sub.2 --CH.sub.b F.sub.3-b wherein a is 0 or the integer 1 or 2 and b is 0 or the integer 1, 2 or 3. In the first step of the process, a chlorinated olefinic hydrocarbon of the formula CH.sub.c Cl.sub.2-c .dbd.CH--CH.sub.d Cl.sub.3-d wherein c is 0 or the integer 1 and d is 0 or the integer 1 or 2 is reacted with anhydrous hydrogen fluoride for a period of time and at a temperature sufficient to form a chlorofluoro olefin of the formula CH.sub.e Cl.sub.2-e .dbd.CH--CH.sub.f F.sub.3-f wherein e is 0 or the integer 1 and f is 0 or the integer 1 or 2. The chlorofluoro olefin produced in the first step is then reacted with anhydrous hydrogen fluoride in a second reaction. This second reaction is catalyzed with at least one compound that is a metal oxide or metal halide. Mixtures of said metal oxides, metal halides and metal oxides with metal halides may also be used. The metallic part of such compound is arsenic, antimony, tin, boron or is selected from a metal in Group IVb, Vb. VIb. VIIb or VIIIb of the Periodic Table of the Elements. The desired fluorinated aliphatic hydrocarbon is subsequently separated and recovered. The process is particularly suitable for the preparation of 1,1,1,3,3-pentafluoropropane.

Dependencies are inferred from the claim text.