Abstract: A process for producing hexafluoroethane, comprising a step of distilling a crude hexafluoroethane containing chlorine compounds each having two carbon atoms to distill out hexafluoroethane as a top flow from the top of a distillation column and separate a hexafluoroethane mixture containing the chlorine compounds as a bottom flow from the bottom, and a step of contacting the bottom flow with hydrogen fluoride in the gas phase at a temperature of 300 to 500° C. in the presence of a fluorination catalyst to fluorinate the chlorine compounds. This process provides hexafluoroethane which can be used mainly as a cleaning gas in the production process of a semiconductor device.

Abstract: A process for producing hexafluoroethane, comprising a step of distilling a crude hexafluoroethane containing chlorine compounds each having two carbon atoms to distill out hexafluoroethane as a top flow from the top of a distillation column and separate a hexafluoroethane mixture containing the chlorine compounds as a bottom flow from the bottom, and a step of contacting the bottom flow with hydrogen fluoride in the gas phase at a temperature of 300 to 500° C. in the presence of a fluorination catalyst to fluorinate the chlorine compounds. This process provides hexafluoroethane which can be used mainly as a cleaning gas in the production process of a semiconductor device.

Abstract: Denitrated combustion exhaust gas is desulfurized with ammonia, the waste water obtained from washing the desulfurization waste water or dust ash is filtered using calcium carbonate, the pH of the filtrate is adjusted, carbon dioxide and/or aqueous carbonic acid is added and then a flocculating agent is added, and ammonia is recovered from the supernatant after precipitation and separation of the solid portion. The recovered ammonia is added to the denitrated gas for treatment of the combustion exhaust gas.

Abstract: Denitrated combustion exhaust gas is desulfurized with ammonia, the waste water obtained from washing the desulfurization waste water or dust ash is filtered using calcium carbonate, the pH of the filtrate is adjusted, carbon dioxide and/or aqueous carbonic acid is added and then a flocculating agent is added, and ammonia is recovered from the supernatant after precipitation and separation of the solid portion. The recovered ammonia is added to the denitrated gas for treatment of the combustion exhaust gas.

Abstract: In a process for production of allyl chloride whereby allyl alcohol and hydrogen chloride are reacted in the presence of a catalyst and the resulting allyl chloride is distilled off from the reaction system, the by-production of diallyl ether is suppressed by lowering the molar concentration ratio of hydrogen chloride with respect to allyl alcohol in the reaction solution ([AAL]½/[HCL]).

Abstract: In a process for production of allyl chloride whereby allyl alcohol and hydrogen chloride are reacted in the presence of a catalyst and the resulting allyl chloride is distilled off from the reaction system, the by-production of diallyl ether is suppressed by lowering the molar concentration ratio of hydrogen chloride with respect to allyl alcohol in the reaction solution ([AAL]½/[HCL]).

Abstract: A purification method for purifying hexafluoroethane, comprising a step of making hexafluoroethane containing impurities of hydrofluorocarbons including two carbon atoms in a molecule contact a zeolite having a mean micropore size in a range of 3.5 Å to 11 Å and a silicon/aluminum ratio of not more than 1.5 or an adsorbent comprising the above-described zeolite and a carbonaceous adsorbent having a mean micropore size in a range of 3.5 Å to 11 Å, thereby reducing said hydrofluorocarbons.

Abstract: A process for producing dichloroacetoxypropane comprising reacting allyl acetate with chlorine in a gaseous phase in the presence of a catalyst. The dichloroacetoxypropane obtained may be converted to dichloropropanol and epichlorohydrin.

Abstract: A production method of perfluorocarbon comprising a main reaction step of making a hydrofluorocarbon and fluorine gas of raw materials react in vapor phase with each other to obtain a reaction product gas containing a perfluorocarbon and residual fluorine gas, and a fluorine gas removing step of making the reaction product gas effluent from the main reaction step contact a hydrofluorocarbon having a chemical equivalent not less than 1.1 mol times a chemical equivalent of the fluorine gas contained in the reaction product gas, thereby removing the fluorine gas.

Abstract: A process for producing tetrafluoromethane which comprises reacting a hydrofluorocarbon containing one carbon atom in the molecule with fluorine gas at an elevated temperature in a vapor phase in the presence of a diluent gas.

Abstract: A process for producing hexafluoroethane which comprises reacting a hydrofluorocarbon containing two carbon atoms in the molecule with fluorine gas at an elevated temperature in a vapor phase in the presence of a diluent gas.

Abstract: A process for producing perfluorocarbons which comprises a step of contacting a hydrofluorocarbon with fluorine gas in a vapor phase at an elevated reaction temperature in a first reaction zone to obtain a gaseous reaction mixture; and a step of introducing the gaseous reaction mixture as a diluent gas into a second reaction zone and contacting the same therein at an elevated reaction temperature with a hydrofluorocarbon fed to the second reaction zone if necessary together with fluorine gas, the hydrofluorocarbon fed to the second reaction zone being different from the hydrofluorocarbon reacted in the first reaction zone.

Abstract: A process for purifying 1,1,1,2-tetrafluoroethane which comprises allowing an HF-containing 1,1,1,2-tetrafluoroethane-concentrated fraction to contact at a low temperature with hydrofluoric acid which is an extraction solvent and has an HF concentration equal to or higher than an HF concentration at a water-HF azeotropic point, thereby effecting two-phase separation, and subsequently recovering 1,1,1,2-tetrafluoroethane from the separated lower phase, wherein hydrofluoric acid to be used as the extraction solvent has a concentration of from 38 to 70% by weight, and the extraction and two-phase separation steps are effected at a temperature of from -35.degree. to 35.degree. C. According to the purification process, HF can be recovered economically from a 1,1,1,2-tetrafluoroethane fraction containing a small amount of HF.

Abstract: A process for producing 1,1,1,2-tetrafluoroethane from trichloroethylene and HF, which comprises introducing products of a reaction of trichloroethylene with HF, and products of a reaction of 1,1,1-trifluoro-2-chloroethane with HF into a first distillation column either separately or as a mixture thereof, recovering HCl as a distillate from the top of the first distillation column, and introducing the remainder into a second distillation column.

Abstract: A process for producing 1,1,1,2-tetrafluoroethane through a reaction of trichloroethylene with HF, which comprises the steps of:(a) allowing trichloroethylene to react with HF in a first reactor to form 1,1,1-trifluoro-2-chloroethane,(b) allowing 1,1,1-trifluoro-2-chloroethane to react with HF in a second reactor to form 1,1,1,2-tetrafluoroethane,(c) introducing the products of the above steps (a) and (b) into a first distillation column where the products are separated into a distillate containing 1,1,1,2-tetrafluoroethane and HCl as main components, a side-cut fraction containing 1,1,1-trifluoro-2-chloroethane and HF as main components and a bottom liquid containing HF as a main component and a small amount of trichloroethylene, and(d) introducing the distillate of the above step (c) into a second distillation column where HCl is recovered as a distillate and a 1,1,1,2-tetrafluoroethane fraction containing small amounts of 1,1,1-trifluoro-2-chloroethane and HF is discharged from the bottom of the second dis

Abstract: A process for purifying 2,3-dichloro-1-propanol is disclosed, which comprises introducing a chlorination reaction mixture obtained by chlorination of allyl alcohol in a hydrochloric acid aqueous solution in a reactor, to a degassing tower, where hydrogen chloride is released, returning the hydrogen chloride to the chlorination reactor, cooling the residual liquid to separate into an aqueous layer and an oily layer, and returning the aqueous layer to the chlorination reactor while recovering 2,3-dichloro-1-propanol from the oily layer, wherein said oily layer is introduced to a first distillation tower, where hydrogen chloride, part of the produced 2,3-dichloro-1-propanol, and other low-boiling components are recovered as a distillate, cooling the distillate to separate it into an aqueous layer and an oily layer, returning the aqueous layer of the distillate to the chlorination reactor, and recovering 2,3-dichloro-1-propanol from the oily layer of the distillate and a high-boiling fraction of the first distill