Process for preparing 1,1,1,2-tetrafluoroethane
AssigneeDaikin Industries, Ltd.
InventorsSatoshi Koyama, Yukio Homoto, Naoki Esaka
Life of this patent
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Abstract
In a process for preparing 1,1,1-trifluorochloroethane by reacting, in a gas phase, trichloroethylene and hydrogen fluoride, when the reactant gases are diluted with a gas which is inactive to the reaction, it is very easy to control a reaction temperature, and when a generated gas from the reaction of 1,1,1-trifluorochloroethane and hydrogen fluoride is used as a diluent gas, generation of 1,1-difluoroethylene is suppressed to a very low level while not influencing the reaction between trichloroethylene and hydrogen fluoride.
Claims2
A process for preparing 1,1,1,2-tetrafluoroethane which comprises the steps of:
- (1) reacting trichloroethylene with hydrogen fluoride in the gas phase at a temperature of about 180.degree. C. to 300.degree. C. in the presence of a fluorination catalyst to obtain 1,1,1-trifluorochloroethane in a first reaction zone,
- (2) introducing the reaction mixture from the first reaction zone to a second reaction zone,
- (3) reacting 1,1,1-trifluorochloroethane from the first reaction zone with hydrogen fluoride in the gas phase at a temperature of about 300.degree. C. to 400.degree. C. in the presence of a fluorination catalyst to obtain 1,1,1,2-tetrafluoroethane in the second reaction zone,
- (4) recycling the entire reaction mixture including 1,1,1,2-tetrafluoroethane from the second reaction zone to the first reaction zone,
- (5) separating 1,1,1,2-tetrafluoroethane and hydrogen chloride from the reaction mixture product from the first reaction zone of step (4) between the first and second reaction zones, and
- (6) recovering 1,1,1,2-tetrafluoroethane from the 1,1,1,2-tetrafluoroethane and hydrogen chloride of step (5).
Dependencies are inferred from the claim text.