Method for preparing a hydro(chloro)fluoroalkane and catalyst
AssigneeSolvay (Societe Anonyme)
InventorsVincent Wilmet, Francine Janssens
Life of this patent
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Abstract
Process for the preparation of a hydro(chloro)fluoroalkane according to which a halogenated precursor of the hydro(chloro)fluoroalkane is reacted with hydrogen fluoride in the presence of a catalyst comprising chromium (Cr) and at least one other metal selected from the group consisting of aluminium, barium, bismuth, calcium, cerium, copper, iron, magnesium, strontium, vanadium and zirconium.
Claims17
1—Process for the preparation of a hydro(chloro)fluoroalkane according to which a halogenated precursor of the hydro(chloro)fluoroalkane is reacted with hydrogen fluoride in the presence of a catalyst comprising chromium (Cr) and at least one other metal (M) selected from aluminium, barium, bismuth, calcium, cerium, copper, iron, magnesium, strontium, vanadium and zirconium, in which process the content of ammonium ions NH4+ in the catalyst is at most 1% by weight.
2—process according to claim 1, in which the content of ammonium ions in the catalyst is at most 0.2% by weight.
3—Process according to claim 1 or 2, in which the catalyst exhibits a specific surface, determined according to the BET method, of at least 15 m2/g.
4—Process according to any one of claims 1 to 3, in which the catalyst was obtained by fluorination of a mixed oxide of chromium and of metal M.
5—Process according to claim 4, in which the mixed oxide was obtained by coprecipitation by reaction of an aqueous solution of soluble metal and chromium salts, which is reacted with an aqueous ammonia solution.
6—Process according to claim 4 or 5, in which the mixed oxide exhibits, before fluorination, a specific surface, determined according to the BET method, of at least 150 m2/g.
7—Process according to any one of claims 1 to 6, applied to the synthesis of a hydrofluoroalkane.
8—Process according to claim 7, in which the metal is selected from aluminium, calcium, cerium, vanadium and zirconium.
9—Process according to claim 8, in which the metal is aluminium.
10—Process according to claim 9, in which the Al/Cr atomic ratio is from 0.5 to 20.
11—Process according to any one of claims 7 to 10, in which the hydrofluoroalkane obtained is pentafluoroethane.
12—Process according to any one of claims 1 to 6, applied to the synthesis of a hydrochlorofluoroalkane.
13—Process according to claim 12, in which the metal is selected from barium, bismuth, copper, iron, magnesium and strontium.
14—Catalyst comprising chromium (Cr) and at least one other metal (M) selected from aluminium, barium, bismuth, calcium, cerium, copper, iron, magnesium, strontium, vanadium and zirconium, in which catalyst the content of ammonium ions NH4+ is at most 1% by weight.
15—Catalyst according to claim 14, in which the content of ammonium ions NH4+ is at most 0.2% by weight.
16—Mixed oxide comprising chromium (Cr) and at least one other metal selected from aluminium, barium, bismuth, calcium, cerium, copper, iron, magnesium, strontium, vanadium and zirconium, in which mixed oxide the content of ammonium ions NH4+ is at most 1% by weight.
17—Mixed oxide according to claim 16, in which the content of ammonium ions NH4+ is at most 0.2% by weight.