Abstract: A process is disclosed for producing difluoromethane by fluorinating dichloromethane with hydrogen fluoride in a liquid phase in the presence of a catalyst, wherein the reaction is conducted at a temperature within the range from 80 to 150° C. under a pressure within the range from 8 to 80 kg/cm2 using a mixture of antimony pentafluoride and antimony trifluoride, or antimony pentafluoride as the fluorinating catalyst. The process economically and safely produces difluoromethane from dichloromethane and hydrogen fluoride.

Abstract: A process for refining difluoromethane by removing hydrogen fluoride, which is contained in difluoromethane difficult to remove. The process involves distilling a mixture of difluoromethane with hydrogen fluoride where the mixture is in contact with sulfuric acid. The hydrogen fluoride remains in the liquid phase and the difluoromethane goes into the vapor phase.

Abstract: There is provided a process for producing HFC-125 and/or HCFC-124 from PCE, characterized by the first reaction step of fluorinating PCE in the presence of catalyst in a liquid phase to form HCFC-123 and/or HCFC-122 and the second reaction step of fluorinating HCFC-123 and/or HCFC-122 in the presence of catalyst in a vapor phase to form HFC-125 and/or HCFC-124.This process is improved in the yield of objective products, and life of catalyst, and the controllability of reaction temperature.

Abstract: There is provided a process for producing HFC-125 and/or HCFC-124 from PCE, characterized by the first reaction step of fluorinating PCE in the presence of catalyst in a liquid phase to form HCFC-123 and/or HCFC-122 and the second reaction step of fluorinating HCFC-123 and/or HCFC-122 in the presence of catalyst in a vapor phase to form HFC-125 and/or HCFC-124.This process is improved in the yield of objective products, and life of catalyst, and the controllability of reaction temperature.

Abstract: Difluoromethane is prepared by reacting dichloromethane and hydrogen fluoride in a liquid phase in the presence of a fluorination catalyst under reaction conditions in which the reaction pressure is between 1 and 10 kg/cm.sup.2 ab., and the reaction temperature is between 50 and 150.degree. C., provided that the selected reaction temperature is higher than a temperature at which hydrogen fluoride is not liquefied under the selected reaction pressure.Under the above conditions, the conversions of dichloromethane and HF are very high, and amounts of by-products other than R30 are very low, typically less than 0.1% per difluoromethane, when the unreacted materials are recycled.A material of a reactor is hardly corroded by the reaction using an antimony chlorofluoride and HF which are highly corrosive, as long as the above conditions are maintained.

Abstract: An object is to effectively preparing a fluorinated compound by developing a catalyst which is effective in the fluorination of a halogenated alkane or alkene with hydrogen fluoride by a gas phase fluorination or addition of hydrogen fluoride. To this end, a catalyst which comprises a least one element selected from the group consisting of Ti, V, Zr, Mo, Ge, Sn and Pb, and alumina, aluminum fluoride or partially fluorinated alumina is used. This catalyst is prepared by an impregnation method to support the above element on alumina and the like, or a precipitation method in which the catalyst is co-precipitated from a solution containing an aluminum compound and a compound of the above element.