Process for preparing 1,1,1-trifluorochloroethane and 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 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 in the presence of a fluorination catalyst to obtain 1,1,1,2-tetrafluoroethane and by-product 1,1-difluorochloroethylene 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) reacting 1,1-difluorochloroethylene produced in the second reaction zone with hydrogen fluoride to reduce the amount of 1,1-difluorochloroethylene in the first reaction zone, and
- (6recovering 1,1,1,2-tetrafluoroethane and hydrogen chloride formed as a by-product from the reaction mixture from the first reaction zone between the first and second reaction zones,
- wherein prior to the recovery of 1,1,1,2-tetrafluoroethane from the reaction mixture from the first reaction zone in the step (6), the reaction mixture from the first reaction zone is passed through a third reaction zone in which 1,1-difluorochloroethylene contained in the reaction mixture from the first reaction zone is reacted with hydrogen fluoride in the gas phase in the presence of a fluorination catalyst to reduce the amount of 1,1-difluorochloroethylene.
Dependencies are inferred from the claim text.