Fluorination catalyst and process

Claim 2

A process for the production of saturated fluorinated hydrocarbons which comprises reacting a halogenated hydrocarbon having from 1 to 4 carbon atoms and selected from halogenated alkenes and halogenated alkanes with hydrogen fluoride in the vapour phase in the presence of a fluorination catalyst comprising an activity-promoting amount of a compound of zinc supported on a chromia, halogenated chromia or chromium oxyhalide support.

Claim 3

A process as claimed in claim 1 in which the halogenated hydrocarbon is selected from the group consisting of 1-chloro-2,2,2-trifluoroethane, trichloroethylene, 1-chloro-2,2-difluoroethylene and perchloroethylene.

Claim 4

A process as claimed in claim 2 in which 1-chloro-2,2,2-trifluoroethane is reacted with hydrogen fluoride in the vapour phase whereby to produce 1,1,1,2-tetrafluoroethane.

Claim 5

A process as claimed in claim 3 which comprises the steps (a) reacting trichloroethylene with hydrogen fluoride whereby to produce 1-chloro-2,2,2-trifluoroethane and (b) reacting 1-chloro-2,2,2-trifluoroethane with hydrogen fluoride whereby to produce 1,1,1,2-tetrafluoroethane, in which the fluorination catalyst is employed in at least one of steps (a) and (b).

Claim 6

A process as claimed in claim 4 which comprises the steps of: (A) contacting a mixture of 1-chloro-2,2,2-trifluoroethane and hydrogen fluoride with the fluorination catalyst at 250°-350° C. in a first reaction zone whereby to form a product containing 1,1,1,2-tetrafluoroethane and hydrogen chloride together with unreacted starting materials, (B) passing the total product of step A together with trichloroethylene to a second reaction zone containing the fluorination catalyst at 180°-300° C. whereby to form a product containing 1-chloro-2,2,2-trifluoroethane, 1,1,1,2-tetrafluoroethane and hydrogen chloride; (C) treating the product of step B whereby to separate a mixture containing hydrogen chloride and 1,1,1,2-tetrafluoroethane from 1-chloro-2,2,2-trifluoroethane, unreacted hydrogen fluoride and unreacted trichloroethylene; (D) feeding the 1-chloro-2,2,2-trifluoroethane mixture obtained from step C together with additional hydrogen fluoride to said first reaction zone, and (E) recovering 1,1,1,2-tetrafluoroethane from the 1,1,1,2-tetrafluoroethane/hydrogen chloride mixture obtained from step C.

Claim 7

A process as claimed in any one of claims 1 and 2 to 5 wherein the reaction is carried out under superatmospheric pressure.

Claim 8

A process as claimed in any one of claims 1 and 2 to 5 wherein the reaction is carried out at a temperature of from 180° C. to 500° C.

Claim 9

A process as claimed in any one of claims 1 and 2 to 5 which is a continuous process.

Claim 10

A process as claimed in claim 5 wherein the amount of hydrogen fluoride employed in step (A) is from 1 to 10 mole of hydrogen fluoride per mole of 1-chloro-2,2,2-trifluoroethane.

Claim 11

A process as claimed in claim 5 wherein the amount of hydrogen fluoride employed in step (B) is from 10 to 100 mole of hydrogen fluoride per mole of trichloroethylene.