Abstract: The present disclosure provides a method for producing fluoroolefin represented by formula (1): CX1X2?CX3X4, wherein X1, X2, X3, and X4 are the same or different, and represent a hydrogen atom or a fluorine atom, with high selectivity. Specifically, the present disclosure is a method for producing a fluoroolefin represented by formula (1) described above, the method comprising a dehydrofluorination step of bringing a fluorocarbon represented by formula (2): CX1X2FCX3X4H, wherein X1, X2, X3, and X4 are as defined above, into contact with a metal catalyst to perform dehydrofluorination, the dehydrofluorination step being performed in the gas phase in the presence of water, the concentration of the water being less than 500 ppm relative to the fluorocarbon represented by formula (2).

Abstract: The present invention relates to a method for preparing a polyinsaturated perfluorinated compound B from a polyinsaturated perhalogenated compound D having the formula CnX2(n?m+1), in which X is independently selected from one of the halogens, F, Cl, Br or I, provided at least one X is not fluorine; n is the number of carbon atoms and is at least higher than or equal to 4, m is the number of double carbon-carbon bonds and is higher than or equal to 2, wherein the method comprises a step in which compound D is fluorinated in the presence of a fluorinating agent of general formula AFp, in which A is hydrogen, an alkali metal or an alkaline earth metal, and p is 1 or 2, and in the presence of an aprotic organic polar solvent; the method being carried out with a molar ratio of AFp to compound D of less than 1.45*2(n?m+1).

Abstract: The present invention relates to methods, process, and integrated systems for economically producing (E)-1-chloro-3,3,3-trifluoropropene via vapor phase and/or liquid processes.

Abstract: Disclosed is a process for producing 1,2-dichloro-3,3,3-trifluoropropene, which is characterized by that 1-halogeno-3,3,3-trifluoropropene represented by the general formula [1]: (In the formula, X represents a fluorine atom, chlorine atom or bromine atom.) is reacted with chlorine in a gas phase in the presence of a catalyst. It is possible by this process to produce 1,2-dichloro-3,3,3-trifluoropropene in an industrial scale with good yield by using 1-halogeno-3,3,3-trifluoropropene, which is available with a low price, as the raw material.

Abstract: The invention also relates a process for the manufacture of trans 1-chloro3,3,3-trifluoropropene. The process comprises an isomerization step from cis 1233zd to trans 1233zd.

Abstract: The invention also relates a process for the manufacture of trans 1-chloro3,3,3-trifluoropropene. The process comprises an isomerization step from cis 1233zd to trans 1233zd.

Abstract: The invention relates to a process for manufacturing 1,1,1,2-tetrafluoropropene (1234yf, CF3—CF?CH2) from 1,1,3,3-tetrachlororopropene (1230za, CCl2?CH—CHCl2) and/or 1,1,1,3,3-pentachloropropane (240fa, CCl3CH2CHCl2). The process comprises a step of isomerization of 1,1,3,3-tetrafluoropropene (1230za) to 1,1,2,3-tetrachloropropene (1230xa) followed by conversion of the 1,1,2,3-tetrachloropropene (1230xa) to 1,1,1,2-tetrafluoropropene (1234yf) via a hydrofluorination process.

Abstract: The present invention provides a simple three step process for the production of 1,3,3,3-tetrafluoropropene (HFO-1234ze). In the first step, carbon tetrachloride is added to vinyl fluoride to afford the compound CCl3CH2CHClF (HCFC-241fb). HCFC-241fb is then fluorinated with anhydrous HF to afford CF3CH2CHClF (HCFC-244fa) in the second step. Dehydrochlorination of HCFC-244fa, in the third step, affords the desired product, CF3CH?CHF (HFO-1234ze). Following similar chemistry, vinyl chloride may be used in place of vinyl fluoride.

Abstract: The present invention provides a novel method for separating hexafluoropropylene oxide (HFPO) from hexafluoropropylene (HFP), which is capable of reducing the burden on the environment. A mixture including HFPO and HFP is subjected to an extractive distillation operation using, as a solvent, at least one of a fluorine-containing saturated compound represented by the general formula CnHaFb (wherein n, a and b are integers which satisfy: n=3 to 8, 0?a?2n+1, and 1?b?2n+2) thereby separating into a first fraction including HFPO and a second fraction including HFP and the solvent. At least one of 1-bromopropane and 2-bromopropane may be u as the solvent in place of the fluorine-containing saturated compound.

Abstract: A process for the fluorination of haloolefins with elemental fluorine in the presence of anhydrous HF proceeds with high yield and selectivity in the product deriving from the addition of fluorine to the carbon-carbon double bond.

Abstract: The present invention provides a process for preparing at least one chlorine-containing fluorocarbon compound selected from the group consisting of chlorine-containing fluoropropane compounds represented by Formula (1): CFnCl3-nCHClCH2—Cl, wherein n is 1 or 2, and chlorine-containing fluoropropene compounds represented by Formula (2): CFnCl3-nCCl?CH2, wherein n is 1 or 2, wherein the process includes the step of contacting at least one chlorine-containing compound selected from the group consisting of 1,1,1,2,3-pentachloropropane, 1,1,2,3-tetrachloropropene, and 2,3,3,3-tetrachloropropene with hydrogen fluoride in the absence of a catalyst while heating. According to the present invention, the chlorine-containing propane and propene compounds having 1 or 2 fluorine atoms can be prepared by an industrially applicable, simple and effective process.

Abstract: Disclosed is a process for making the compound 1,1,2-trichloro-3,3,3-trifluoropropane (233da) by the catalytic fluorination of 1,1,1,2,3,3-hexachloropropane. 233da is a starting material used in the production cis-1-chloro-3,3,3-trifluoropropene (cis-1233zd).

Abstract: The invention relates to a process for manufacturing 1,1,1,2-tetrafluoropropene (1234yf, CF3—CF?CH2) from 1,1,3,3-tetrachlororopropene (1230za, CCl2?CH—CHCl2) and/or 1,1,1,3,3-pentachloropropane (240fa, CCl3CH2CHCl2). The process comprises an isomerization step of 1-chloro-3,3,3 trifluoropropene (1233zd, CF3—CH?CHCl) to 2-chloro-3,3,3 trifluoropropene (1233xf or CF3—CCl?CH2).

Abstract: The present invention provides a process for the manufacture of trans 1-chloro-3,3,3-trifluoropropene (E-1233zd). The first step of the process comprises the fluorination of 1,1,3,3-tetrachlororopropene (1230za, CCh?CH—CHCh) and/or 1,1,1,3,3-pentaachloropropane (240fa) to a mixture of cis 1233zd (Z-1233zd) and trans 1233zd (E-1233zd). The second step of the process comprises a separation of the mixture formed in the first step to isolate cis 1233zd (Z-1233zd) from the mixture. The third step of the process comprises isomerization of cis 1233zd (Z-1233zd) to trans 1233zd (E-1233zd).

Abstract: The invention relates to new processes for preparation of 18F-fluoroalkyl halides suitable for use in labelling of Positron Emission Tomography (PET) radiotracers. The process of preparation comprises the step of reacting a 18F-fluoroacylhalide with Wilkinson's catalyst.

Abstract: The invention relates to a process for preparing a C3-6 hydrofluoroalkene comprising dehydrohalogenating a C3-6 hydrohalofluoroalkane in the presence of a zinc/chromia catalyst.

Abstract: Disclosed are azeotropic and azeotrope-like mixtures of (Z)-1-chloro-3,3,3-trifluoropropene (1233zd(Z)) and hydrogen fluoride. Such compositions are useful as an intermediate in the production of 1233zd(Z). The latter compound is useful as a nontoxic, zero ozone depleting fluorocarbon useful as a solvent, blowing agent, refrigerant, cleaning agent, aerosol propellant, heat transfer medium, dielectric, fire extinguishing composition and power cycle working fluid.

Abstract: Provided are azeotropic or azeotrope-like mixtures of 1,1,3,3-tetrachloro-1-fluoropropane (HCFC-241fa) and hydrogen fluoride. Such compositions are useful as an intermediate in the production of HFC-245fa and HCFO-1233zd.

Abstract: Disclosed is a process for making the compound 1,1,2-trichloro-3,3,3-trifluoro-propane (233da) by the catalytic fluorination of 1,1,1,2,3,3-hexachloropropane. 233da is a starting material used in the production cis-1-chloro-3,3,3-trifluoropropene (cis-1233zd).

Abstract: A process is disclosed for making CF3CH2CHF2, CF3CH?CHF, and/or CF3CH?CHCl. This process involves reacting at least one starting material selected from the group consisting of halopropenes of the formula CX3CH?CH2 and halopropenes of the formula CX2?CHCH2X, wherein each X is independently F or Cl, with HF and Cl2 in a reaction zone to produce a product mixture comprising HF, HCl, CF3CH2CHF2, CF3CH?CHF and CF3CH?CHCl; and recovering the CF3CH2CHF2, CF3CH?CHF, and/or CF3CH?CHCl from the product mixture. The molar ratio of HF to the total amount of starting materials fed to the reaction zone is at least stoichiometric, and the molar ratio of Cl2 to total amount of starting material fed to the reaction zone is 2:1 or less.

Abstract: The disclosed integrated manufacturing process includes a combined liquid phase reaction and purification operation which directly produces trans-1-chloro-3,3,3-trifluoropropene and 3-chloro-1,1,1,3-tetrafluoropropane which is a precursor to the manufacture of trans-1,3,3,3-tetrafluoropropene. The mixture of co-products is easily separated by conventional distillation and 3-chloro-1,1,1,3-tetrafluoropropane is then dehydrochlorinated to produce trans-1,3,3,3-tetrafluoropropene by contacting in the liquid phase with a caustic solution or in the vapor phase using a dehydrochlorination catalyst.

Abstract: To provide a process for producing a fluoroalkyl iodide, whereby the selectivity for a fluoroalkyl iodide having a desired degree of polymerization is high and the productivity is high. A process for producing a fluoroalkyl iodide (2) represented by RfCF2CF2I (wherein Rf is a fluoroalkyl group having at most 4 carbon atoms), which comprises reacting a fluoroalkyl iodide (1) represented by RfI with tetrafluoroethylene in the presence of a radical initiator, wherein a first reaction step of supplying and reacting tetrafluoroethylene and a radical initiator to the fluoroalkyl iodide (1), is followed by repeating (n?1) times (provided that n is an integer of at least 3) a subsequent reaction step of supplying and reacting a radical initiator, or a radical initiator and tetrafluoroethylene, to a reaction mixture (1) formed in the first reaction step.

Abstract: To provide processes for efficiently and economically producing 2-chloro-1,1,1,2-tetrafluoropropane (R244bb) and 2,3,3,3-tetrafluoropropene (R1234yf) in an industrially practical manner. A process for producing 2-chloro-1,1,1,2-tetrafluoropropane, which comprises a chlorination step of reacting 1,2-dichloro-2-fluoropropane and chlorine in the presence of a solvent under irradiation with light to obtain 1,1,1,2-tetrachloro-2-fluoropropane, and a fluorination step of reacting the 1,1,1,2-tetrachloro-2-fluoropropane obtained in the chlorination step and hydrogen fluoride in the presence of a catalyst to obtain 2-chloro-1,1,1,2-tetrafluoropropane, and a process for producing 2,3,3,3-tetrafluoropropene, which comprises dehydrochlorinating it in the presence of a catalyst.

Abstract: Disclosed are azeotropic and azeotrope-like mixtures of (Z)-1-chloro-3,3,3-trifluoropropene (1233zd(Z)) and hydrogen fluoride. Such compositions are useful as an intermediate in the production of 1233zd(Z). The latter compound is useful as a nontoxic, zero ozone depleting fluorocarbon useful as a solvent, blowing agent, refrigerant, cleaning agent, aerosol propellant, heat transfer medium, dielectric, fire extinguishing composition and power cycle working fluid.

Abstract: A method for producing a tetrafluoroolefin, such as 2,3,3,3-tetrafluoropropene (HFO-1234yf), comprises contacting 1,1,1,2-tetrachloro-2-fluoropropane (HCFC-241bb) with or without a catalyst under conditions effective to convert the 1,1,1,2-tetrachloro-2-fluoropropane (HCFC-241bb) to the tetrafluoroolefin, optionally, via an intermediate. The conversion may be a one-step fluorination or a two-step fluorination and dehydrochlorination process. The 1,1,1,2-tetrachloro-2-fluoropropane (HCFC-241bb) may also be obtained by dehydrochlorinating 1,2,3-trichloropropane (HCC-260da) to form 2,3-dichloropropene (HCO-1250xf); fluorinating 2,3-dichloropropene (HCO-1250xf) to form 1,2-dichloro-2-fluoropropane (HCFC-261bb); and chlorinating 1,2-dichloro-2-fluoropropane (HCFC-261bb) to form 1,1,1,2-tetrachloro-2-fluoropropane (HCFC-241bb).

Abstract: A method of catalytically converting 2,2, dichlorohexafluoropropane (HFC-216aa) into 2 chloro 1,1,1,2,3,3,3 heptafluoropropane (HFC-217ba) including the step of exposing the 2,2 dichlorohexafluoropropane to a chromium-containing catalyst comprising a metal oxide, a halogenated metal oxide or a metal oxyhalide, which chromium-containing catalyst comprises 0.01% to 5.0% by weight zinc or a compound of zinc.

Abstract: A process is disclosed for making CF3CF2CH3, CF3CF?CH2 and/or CF3CCl?CH2. The process involves reacting at least one starting material selected from the group consisting of halopropanes of the formula CX3CH2CH2X, halopropenes of the formula CX3CH?CH2 and halopropenes of the formula CX2?CHCH2X, wherein each X is independently F or Cl, with HF and Cl2 in a reaction zone to produce a product mixture comprising HF, HCl, CF3CF2CH3, CF3CF?CH2, and CF3CCl?CH2; and recovering the CF3CF2CH3, CF3CF?CH2 and/or CF3CCl?CH2 from the product mixture. Also disclosed is a process for making CF3CH2CHF2, CF3CH?CHF, and/or CF3CH?CHCl.

Abstract: The invention is directed to a process for preparing 2,2,2,3-tetrafluoropropene (1234yf), comprising: (i) contacting 1,1,2,3-tetrachloropropene (1230xa) with hydrogen fluoride HF in gas phase in the presence of a fluorination catalyst under conditions sufficient to produce a reaction mixture; (ii) separating the reaction mixture into a first stream comprising HCl, 2,2,2,3-tetrafluoropropene (1234yf) and a second stream comprising HF, 2-chloro-3,3,3-trifluoro-1-propene (1233xf) and 1,1,1,2,2-pentafluoropropane (245cb); (iii) recycling at least a part of the second stream at least in part back to step (i).

Abstract: The invention is directed to a process for preparing 2,3,3,3-tetrafluoropropene (1234yf), comprising: (i) contacting 1,1,2,3-tetrachloropropene (1230xa) with hydrogen fluoride HF in gas phase in the presence of a fluorination catalyst under conditions sufficient to produce a reaction mixture; (ii) separating the reaction mixture into a first stream comprising HCl, 2,3,3,3-tetrafluoropropene (1234yf) and a second stream comprising HF, 2-chloro-3,3,3-trifluoro-1-propene (1233xf) and 1,1,1,2,2-pentafluoropropane (245cb); (iii) recycling at least a part of the second stream at least in part back to step (i).

Abstract: Disclosed are processes for the production of fluorinated olefins, preferably adapted to commercialization of CF3CF?CH2 (1234yf). In certain preferred embodiments the processes comprise first exposing a compound of Formula (IA) C(X)2?CClC(X)3??(IA) where each X is independently F, Cl or H, preferably CCl2?CClCH2Cl, to one or more sets of reaction conditions, but preferably a substantially single set of reaction conditions, effective to produce at least one chlorofluoropropane, preferably in accordance with Formula (IB): CF3CClX?C(X?)3??Formula (IB) where each X? is independently F, Cl or H, and then exposing the compound of Formula (IB) to one or more sets of reaction conditions, but preferably a substantially single set of reaction conditions, effective to produce a compound of Formula (II) CF3CF?CHZ??(II) where Z is H, F, Cl, I or Br.

Abstract: A process is disclosed for making CH2ClCF2CClF2. The process involves reacting CH2ClF with CClF?CF2 in an addition reaction zone in the presence of an aluminum halide composition having a bulk formula of AlClxBryF3-x-y wherein the average value of x is 0 to 3, the average value of y is 0 to 3?x, provided that the average values of x and y are not both 0. Also disclosed is a process for making CH2FCF2CF3 that involves reacting the CH2ClCF2CClF2 with HF in a fluorination reaction zone in the presence of a fluorination catalyst. Also disclosed is a process for making CHF?CFCF3 that involves dehydrofluorinating the CH2FCF2CF3.

Abstract: A process for the preparation of a fluoroiodoalkane compound represented by the formula: CF3(CF2)n—Y, wherein n is 0 or 1. The process includes contacting A, B and C. A is represented by the formula: CF3(CF2)n—Y, wherein n is 0 or 1, and Y is selected from the group consisting of: H, Cl, Br, and COOH. B is a source of iodine, and C is a catalyst containing elements with d1s1 configuration and lanthanide elements. The process occurs at a temperature, and for a contact time, sufficient to produce the fluoroiodoalkane compound.

Abstract: The process for recovering pentafluoroethane of the invention includes bringing a mixed gas containing pentafluoroethane and a non-condensable gas into contact with a chlorinated solvent, and allowing the chlorinated solvent to absorb pentafluoroethane contained in the mixed gas. The process for the production of pentafluoroethane of the invention uses the recovering process.

Abstract: A photochemical reaction apparatus including a reactor and a light source situated so that light from the light source is directed through a portion of the reactor wall is disclosed. The apparatus is characterized by the portion of the reaction wall comprising a copolymer of a perfluoro (alkyl vinyl ether). The perfluoro (alkyl vinyl ether) is selected from the group consisting of CF30CF?CF2, C2F5OCF?CF2, C3F7OCF?F2, and mixture thereof. Also disclosed is a photochemical reaction process wherein light from a light source is directed through said reactor wall to interact with reactants in said reactor. A process for increasing the fluorine content of at least one compound selected from hydrocarbons and halohydrocarbons, comprising: (a) photochlorinating said at least one compound; and (b) reacting the halogenated hydrocarbon produced in (a) with HF.

Abstract: An alkali metal fluoride dispersion essentially consisting of an alkali metal fluoride and an aprotic organic solvent obtainable by conducting the following Step (A), subsequently conducting the following Step (B) at least once, and then conducting the following Step(C); Step (A): a step of separating a liquid phase from an alkali metal fluoride dispersion comprising at least one alcohol solvent selected from the group consisting of methanol, ethanol and isopropanol and an alkali metal fluoride, and mixing the separated liquid phase with an aprotic organic solvent having a boiling point of 85° C.

Abstract: A method for producing 1,4-bis(bromodifluoromethyl)tetrafluorobenzene (BFTFB) is disclosed. The target compound is predicted as a very potent monomer for low dielectric constant material. This method comprises the following steps: (a) mixing 1,4-bis(bromodifluoromethyl)tetrafluorobenzene (DFMTFB), a bromination agent, and a solvent (with or without) to form a mixture; (b) heating the mixture under UV radiation; and (c) purifying the resultant to obtain 1,4-bis(bromodifluoromethyl)tetrafluorobenzene (BFTFB) with high purity.

Abstract: A method of catalytically converting 2,2, dichlorohexafluoropropane (HFC-216aa) into 2 chloro 1,1,1,2,3,3,3 heptafluoropropane (HFC-217ba) including the step of exposing the 2,2 dichlorohexafluoropropane to a chromium-containing catalyst comprising a metal oxide, a halogenated metal oxide or a metal oxyhalide, which chromium-containing catalyst comprises 0.01% to 5.0% by weight zinc or a compound of zinc.

Abstract: The invention provides an economic process for the manufacture of 1,3,3,3-tetrafluoropropene (HFO-1234ze) by a two stage process. A vapor phase hydrofluorination of 1-chloro-3,3,3-trifluoropropene (HCFC-1233zd) into 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa) and/or 1,1,1,3,3-pentafluoropropane (HFC-245fa) is conducted, followed by the thermal dehydrochlorination of HCFC-244fa and dehydro fluorination of HFC-245fa into HFO-1234ze in the presence of a catalyst which comprises one or more of alkali metal halides, alkaline earth metal halides, halogenated metal oxides, zero oxidation state metals, zinc halides, palladium halides, and activated carbon.

Abstract: A process is described for the preparation of 2-chloro-1,1,1-difluoroethane by the reaction of 1,2-dichloro-1,1-difluoroethane with hydrogen fluoride. in the presence of a fluorination catalyst. The process utilizes a rate enhancing reagent that is trichloroethylene, is 1-fluoro-1,2,3-trichloroethane or an aromatic rate enhancing reagent having the formula where R is C1 to C6 linear or branched alkyl substituted with at least one halo group, halo or nitro and R? is C1 to C6 linear or branched alkyl substituted with at least one halo group.

Abstract: Methods and systems for producing halogenated hydrocarbon compounds with an inorganic fluoride (e.g., germanium tetrafluoride (GeF4)) are disclosed herein.

Abstract: Methods and systems for producing hydrofluorocarbon with an inorganic fluoride (e.g., germanium tetrafluoride (GeF4)) are disclosed herein.

Abstract: Methods and systems for producing halocarbon with an inorganic fluoride (e.g., germanium tetrafluoride (GeF4)) are disclosed herein.

Abstract: Methods and systems for producing chlorofluorocarbon with an inorganic fluoride (e.g., germanium tetrafluoride (GeF4)) are disclosed herein.

Abstract: A telomerisation process is described whereby haloalkanes like tetrachloromethane are added to halogenated olefins like 2-chloroprop-1-ene in the presence of an iron catalyst and a phosphite. The reaction products, e.g. 1,1,1,3,3-pentachlorobutane, can be fluorinated.

Abstract: The invention provides an economic process for the manufacture of 1,3,3,3-tetrafluoropropene (HFC-1234ze) by a two stage process. A hydrofluorination of 1-chloro-3,3,3-trifluoropropene (HCFC-1233zd) into 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa) and 1,1,1,3,3-pentafluoropropane (HFC-245fa) is conducted, followed by the dehydrochlorination of HCFC-244fa and dehydrofluorination of HFC-245fa into HFC-1234ze.

Abstract: Process for the separation of a mixture comprising at least one hydrofluoroalkane and hydrogen fluoride, according to which a hydrofluoroalkane/hydrogen fluoride mixture is reacted with at least one chlorinated or chlorofluorinated precursor of the hydrofluoroalkane. Process for the preparation of a hydrofluoroalkane comprising such a separation, in combination with a catalytic reaction stage. Azeotropic compositions.

Abstract: A method for producing 1,4-bis(difluoromethyl)tetrafluorobenzene is disclosed, which has the following steps: (a) mixing 1,4-bis(dichloromethyl)tetrafluorobenzene, a catalyst, an aprotic polar solvent, and an alkali metal fluoride to form a reaction mixture; (b) heating the reaction mixture; and (c) purifying the resultant to obtain 1,4-bis(difluoromethyl)tetrafluorobenzene.

Abstract: A process for the preparation of 1,1,1,3,3,3-hexafluoropropane is disclosed. The process involves (a) contacting at least one halopropane of the formula CF3CH2CHyX3-y (where each X is independently F, Cl or Br, and y is 3, 2, or 1) with Cl?2#191 in the presence of light or a free radical initiator to produce a mixture comprising CF3CH2CCIyX3-y; (b) contacting the CF3CH2CCIyX3-y produced in step (a) with HF, optionally in the presence of a fluorination catalyst, to produce a product mixture comprising CF3CH2CF3; and (c) recovering CF3CH2CF3 from the mixture produced in step (b).

Abstract: The invention relates to a device and a process for nucleophilic fluorination of a substance, especially for synthesis of an 18F-labeled substance for examination using a positron emission tomograph. The device comprises an anion exchange device (102) for extraction of [18F]fluoride ions by means of adsorption from a target fluid, whereby the anion exchange device (102) can be charged via a supply device (101) with the target fluid; and a measurement device (104) with a measurement chamber (103) for measuring initial radioactivity of the [18F]fluoride ions, the anion exchange device (102) being arranged at least partially in the measurement chamber (103) of the measurement device (104). (FIG.

Abstract: A improved process is described for the preparation of a substantially pure, liquefied stream of 1,1,1,2-tetrafluoroethane by the catalyzed reaction of trichloroethylene with hydrogen fluoride to form the intermediate 2-chloro-1,1,1-trifluoroethane and then reacting said intermediate 2-chloro-1,1,1-trifluoroethane with hydrogen fluoride, in the presence of a hydrofluorination catalyst to form a reaction stream containing 1,1,1,2-tetrafluoroethane. The improvement comprises liquefying the by-product hydrogen chloride formed in the preparation of the intermediate 2-chloro-1,1,1-trifluoroethane and countercurrently passing said liquefied hydrogen chloride thru the reaction stream containing 1,1,1,2-tetrafluoroethane thereby forming a substantially pure, liquefied stream of 1,1,1,2-tetrafluoroethane and an effluent comprising gaseous hydrogen chloride.