WO2024110731A1

WO2024110731A1 - Method for purifying chlorotrifluoroethylene by extractive distillation

Info

Publication number: WO2024110731A1
Application number: PCT/FR2023/051836
Authority: WO
Inventors: Alexandre CAMBRODON; Cédric LAVY; Abdelatif BABA-AHMED
Original assignee: Arkema France
Priority date: 2022-11-23
Filing date: 2023-11-22
Publication date: 2024-05-30
Also published as: FR3142187A1

Abstract

The present invention relates to a method for purifying chlorotrifluoroethylene (CTFE) from a first composition comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane (143), the method comprising the steps of: a) extractive distillation of the first composition in the presence of at least one organic extractant to form i) a second composition comprising the organic extractant and the 1,1,2-trifluoroethane and ii) a first stream comprising the chlorotrifluoroethylene; and b) recovery and separation of the second composition to form a second stream comprising the organic extractant and a third stream comprising the 1,1,2-trifluoroethane; preferably, the second stream is recycled to step a).

Description

DESCRIPTION

Title: Process for purifying

extractive distillation

Domain

The present invention relates to a process for the production and purification of hydrofluoroolefins. In particular, the present invention relates to a process for purifying chlorotrifluoroethylene. The present invention also relates to a process for producing trifluoroethylene (VF ₃ ) by hydrogenolysis of chlorotrifluoroethylene.

Technological background of the invention

Fluorinated olefins, such as VF ₃ , are known and are used as monomers or comonomers for the manufacture of fluorocarbon polymers having remarkable characteristics, in particular excellent chemical resistance and good thermal resistance.

Trifluoroethylene is a gas under normal conditions of pressure and temperature. The main risks associated with the use of this product concern its flammability, its propensity for self-polymerization when not stabilized, its explosiveness due to its chemical instability and its supposed sensitivity to peroxidation, by analogy with other halogenated olefins. Trifluoroethylene has the particularity of being extremely flammable, with a lower explosion limit (LEL) of approximately 10% and an upper explosion limit (UEL) of approximately 30%. The major danger, however, is associated with the propensity of VF ₃ to decompose violently and explosively under certain pressure conditions in the presence of an energy source, even in the absence of oxygen.

Given the main risks above, the synthesis and storage of VF ₃ pose particular problems and impose strict safety rules throughout these processes. A known route for preparing trifluoroethylene uses chlorotrifluoroethylene (CTFE) and hydrogen as starting products in the presence of a catalyst and in the gas phase. We know from WO 2013/128102 a process for producing trifluoroethylene by hydrogenolysis of CTFE in the gas phase and in the presence of a catalyst based on a metal from group VIII at atmospheric pressure and at low temperatures. It is known from application PCT/FR2022/051054 that the reaction generates a reaction stream comprising, in addition to trifluoroethylene and unreacted chlorotrifluoroethylene, 1,1,2-trifluoroethane. Chlorotrifluoroethylene and 1,1,2-trifluoroethane form an azeotrope under certain conditions. The recovery of chlorotrifluoroethylene with high purity for recycling is therefore complex. There is thus a need for a process for purifying chlorotrifluoroethylene. Summary of the invention

According to a first aspect, the present invention provides a process for purifying chlorotrifluoroethylene (CTFE) from a first composition comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane (143), said process comprising the steps of: a) Extractive distillation of said first composition in the presence of at least one organic extractant to form i) a second composition comprising said organic extractant and 1,1,2-trifluoroethane; and ii) a first stream comprising chlorotrifluoroethylene, and b) recovery and separation of said second composition to form a second stream comprising said organic extractant and a third stream comprising 1,1,2-trifluoroethane, preferably said second current is recycled in step a).

According to a preferred embodiment, said organic extractant has a flash point greater than 13°C.

According to a preferred embodiment, said organic extraction agent is a compound comprising from 2 to 12 carbon atoms.

According to a preferred embodiment, said organic extraction agent has a molecular mass of less than 200 g. mol ¹ .

According to a preferred embodiment, said organic extractant has a separation factor Si, 2 greater than or equal to 2.0, said separation factor being calculated by the formula Si, 2 = (yi,s)/(y2 ,s) in which yi,s represents the activity coefficient of chlorotrifluoroethylene in said organic extractant at infinite dilution, y2,s represents the activity coefficient of 1,1,2-trifluoroethane in said extractant organic with infinite dilution, advantageously, the separation factor Si, ₂ is greater than or equal to 2.1, preferably greater than or equal to 2.2, more preferably greater than or equal to 2.3, in particular greater than or equal to 2 .4, more particularly greater than or equal to 2.5.

According to a preferred embodiment, said organic extraction agent has an absorption capacity C ₂ ,s greater than or equal to 0.20, said absorption capacity being calculated by the formula C2,s = l/(y2, s) in which y2,s represents the activity coefficient of 1,1,2-trifluoroethane in said organic extractant at infinite dilution. According to a preferred embodiment, the first composition is an azeotropic or quasi-azeotropic composition comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane.

According to a preferred embodiment, said organic extractant has a melting point below 0°C.

According to a preferred embodiment, step b) is carried out at a pressure of 1 to 10 bara, preferably 1 to 7 bara.

According to a preferred embodiment, said organic extraction agent is selected from the group consisting of beta-propiolactone, gamma-butyrolactone, l-hydroxy-2-propanone, acetonylacetone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1, 2-ethanedioldiacetate, glycol, ethyloxalat, 3-oxobutanoicacid-l- methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, triethyleneglycol, diethylmalonate, furfural, diethyleneglycol, t-butylacetoacetate, ethylsuccinate,

1.3-propanediol, cyclopentanone, propylene glycol, 1-cyclopropylethanone, 2-methoxyethanol,

2.3-pentanedione, tripropylene glycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3-methoxy-l-butanol, 4-methyl-3-penten-2-one, l-methoxy2-propanol, phenylacetate, cycloheptanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 2,3-hexanedione, 3,4- hexanedione, citral, 1,5-pentanediol, diethyleneglycolmonobutylether, 4-phenyl-2-butanone, ethanol, n-butylacetate, 4-methyl-2-pentanone, 3- hexanone, 4,4-dimethyl-2-pentanone, 5-methyl-2-hexanone, 2,2-dimethylcyclohexanone and ethylbenzoate.

According to another aspect, the present invention provides a process for producing trifluoroethylene in a reactor provided with a fixed catalytic bed comprising a catalyst, said process comprising the steps of:

A') reaction of chlorotrifluoroethylene with hydrogen in the presence of the catalyst and in the gas phase to produce a stream A comprising trifluoroethylene, unreacted chlorotrifluoroethylene and 1,1,2-trifluoroethane;

B') purification of said stream A to form a stream B1 comprising trifluoroethylene and a stream B2 comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane,

C') implementation of the purification process according to the present invention from said stream B2.

Detailed description of the invention

CTFE ion process According to a first aspect of the present invention, a process for purifying chlorotrifluoroethylene (CTFE) is provided. In particular, the present invention makes it possible to separate chlorotrifluoroethylene from 1,1,2-trifluoroethane (143). Mixtures of chlorotrifluoroethylene and 1,1,2-trifluoroethane are obtained during the implementation of trifluoroethylene production processes. Chlorotrifluoroethylene and 1,1,2-trifluoroethane are generally obtained in the form of an azeotropic composition depending on the operating conditions. In order to recover the chlorotrifluoroethylene, it is necessary to separate the constituents of this azeotropic composition. The applicant has surprisingly found organic extraction agents capable of separating chlorotrifluoroethylene and 1,1,2-trifluoroethane by extractive distillation.

Said purification process comprises the steps of: a) Extractive distillation of said first composition in the presence of at least one organic extracting agent to form i) a second composition comprising said organic extracting agent and 1,1,2 -trifluoroethane; and ii) a first stream comprising chlorotrifluoroethylene, b) recovery and separation of said second composition to form a second stream comprising said organic extractant and a third stream comprising 1,1,2-trifluoroethane, preferably said second stream is recycled to step a).

According to a preferred embodiment, said first composition comprises at least 50% by weight of chlorotrifluoroethylene, advantageously at least 60% by weight of chlorotrifluoroethylene, preferably at least 70% by weight of chlorotrifluoroethylene, in particular at least 80% by weight of chlorotrifluoroethylene based on the total weight of the first composition.

According to a preferred embodiment, said first composition comprises at most 30% by weight of 1,1,2-trifluoroethane, advantageously at most 25% by weight of 1,1,2-trifluoroethane, preferably at most 20% by weight of 1,1,2-trifluoroethane, in particular at most 15% by weight of 1,1,2-trifluoroethane based on the total weight of the first composition.

According to a preferred embodiment, the first composition is an azeotropic or quasi-azeotropic composition comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane.

Advantageously, said first composition is azeotropic and comprises from 80% to 99.99% by weight of chlorotrifluoroethylene based on the total weight of said composition. Preferably, said first composition is azeotropic and comprises from 85% to 99.99% by weight of chlorotrifluoroethylene based on the total weight of said composition. In particular, said first composition is azeotropic and comprises from 90% to 99.99% by weight of chlorotrifluoroethylene based on the total weight of said composition.

Advantageously, said first composition is azeotropic and comprises from 0.01% to 20% by weight of 1,1,2-trifluoroethane based on the total weight of said composition. Preferably, said first composition is azeotropic and comprises from 0.01% to 15% by weight of 1,1,2-trifluoroethane based on the total weight of said composition. In particular, said first composition is azeotropic and comprises from 0.01% to 10% by weight of 1,1,2-trifluoroethane based on the total weight of said composition.

Preferably, said first composition is azeotropic and has a boiling point of between -40°C and 40°C, more preferably between -35°C and 25°C. In particular, said first composition is azeotropic and has a boiling point of between -40°C and 40°C at a pressure of between 0.5 bara and 8 bara. More particularly, said first composition is azeotropic and has a boiling point of between -35°C and 25°C at a pressure of 1 bara to 6 bara.

Thus, said first composition is azeotropic and can comprise from 80% to 99.99% by weight of chlorotrifluoroethylene and from 0.01% to 20% by weight of 1,1,2-trifluoroethane based on the total weight of said composition. ; and has a boiling point between -40°C and 40°C at a pressure between 0.5 bara and 8 bara. Advantageously, said first composition is azeotropic and comprises from 85% to 99.99% by weight of chlorotrifluoroethylene and from 0.01% to 15% by weight of 1,1,2-trifluoroethane based on the total weight of said composition; and has a boiling point between -40°C and 40°C at a pressure between 0.5 bara and 8 bara. More particularly, said first composition is azeotropic and comprises from 90% to 99.99% by weight of chlorotrifluoroethylene and from 0.01 to 10% by weight of 1,1,2-trifluoroethane based on the total weight of said composition; and has a boiling point between -30°C and 25°C at a pressure between 1 bara and 6 bara.

According to a preferred embodiment, said organic extraction agent is a solvent chosen from the group consisting of hydrocarbon, hydrohalocarbon, alcohol, ketone, amine, ester, ether, aldehyde, acid, nitrile, carbonate, thioalkyl, amide, heterocycle, sulfate and phosphate. Advantageously, said organic extraction agent is a solvent selected from the group consisting of alcohol, ketone, phosphate, ester and ether.

The term "hydrocarbon" as used herein refers to linear or branched compounds of C1-C20 alkane, C3-C20 cycloalkane, C5-C20 alkene, C5-C20 cycloalkene, Cg-Cis arene. For example, the term alkane refers to compounds with the formula C _n H2n+2 in which n is included between 1 and 20. The term C1-C20 alkane includes for example pentane, hexane, heptane, octane, nonane, decane or isomers thereof. The term C5-C20 alkene refers to hydrocarbon compounds comprising one or more carbon-carbon double bonds and comprising 5 to 20 carbon atoms. The term C3-C20 cycloalkane refers to a saturated hydrocarbon ring comprising 3 to 20 carbon atoms. The term C ₆ -Cis aryl refers to cyclic and aromatic hydrocarbon compounds comprising 6 to 18 carbon atoms. The term C5-C20 cycloalkene refers to cyclic hydrocarbon compounds comprising 5 to 20 carbon atoms and comprising one or more carbon-carbon double bonds.

The term “alkyl” designates a monovalent radical derived from an alkane, linear or branched, comprising from 1 to 20 carbon atoms. The term “cycloalkyl” designates a monovalent radical derived from a cycloalkane comprising from 3 to 20 carbon atoms. The term “aryl” designates a monovalent radical derived from an arene comprising 6 to 18 carbon atoms. The term “alkenyl” designates a monovalent radical of 2 to 20 carbon atoms and at least one carbon-carbon double bond. The term “alkynyl” designates a monovalent radical of 2 to 20 carbon atoms and at least one carbon-carbon triple bond. The term “halogen” refers to a group -F, -Cl, -Br or -I. The term “cycloalkenyl” refers to a monovalent radical derived from a cycloalkene comprising 3 to 20 carbon atoms. The C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C20 cycloalkyl, C3-C20 cycloalkenyl, Cg-Cis aryl substituents may or may not be substituted by one or more -OH substituents, halogen, -NR ^a C(O)R ^b , -C(O)NR ^a R ^b -CN, -NO2, -NR ^a R ^b , -OR ^a , -SR ^a , -CO ₂ R ^a , -OC( O)OR ^a , -OC(O)R ^a , -C(O)H, -C(O)R ^a , in which R ^a and R ^b are independently of each other hydrogen, C1- alkyl Unsubstituted C20, unsubstituted C2-C20 alkenyl, unsubstituted C2-C20 alkynyl, unsubstituted C3-C20 cycloalkyl, unsubstituted C3-C20 cycloalkenyl, unsubstituted Cg-Cis aryl. In the -NR ^a R ^b substituents, R ^a and R ^b can form with the nitrogen atom to which they are attached a saturated or unsaturated heterocycle, aromatic or not, comprising 5 to 10 members.

The term "hydrohalocarbons ^" refers to compounds of formula R ^a C20, aryl in Cg-Cis and X represents a chlorine, fluorine, bromine or iodine atom. The C1-C20 alkyl, C2-C20 alkenyl, C2-C20 alkynyl, C3-C20 cycloalkyl, C3-C20 cycloalkenyl, Cg-Cis aryl substituents may or may not be substituted by one or more -OH substituents, halogen, -NR ^a C(O)R ^b , -C(O)NR ^a R ^b -CN, -NO ₂ , -NR ^a R ^b , -OR ^a , -SR ^a , -CO ₂ R ^a , - OC (O)OR ^a , -OC(O)R ^a , -C(O)H, -C(O)R ^a , in which R ^a and R ^b are as defined above.

The term "alcohol" refers to hydrocarbons or hydrohalocarbons as defined above in which at least one hydrogen atom is replaced by an -OH hydroxyl group. The term "ketone" refers to hydrocarbons comprising at least one or more carbonyl functional groups R ^c -C(O)-R ^d in which R ^c and R ^d are independently of each other a C1- alkyl C20, C2-C20 alkenyl, C2-C20 alkynyl, C3-C20 cycloalkyl, C3-C20 cycloalkenyl, Cg-Cis aryl may or may not be substituted by one or more -OH, halogen, -NR ^a C substituents (O)R ^b , -C(O)NR ^a R ^b -CN, -NO ₂ , -NR ^a R ^b , -OR ^a , -SR ^a , -CO ₂ R ^a , -OC(O)OR ^a , -OC(O)R ^a , - C(O)H, -C(O)R ^a , in which R ^a and R ^b are as defined above, R ^c and R ^d being able to be linked together to form with the carbonyl group to which they are attached a cyclic ketone comprising from 4 to 10 members, preferably from 4 to 7 members. The cyclic ketone may also include one or more carbon-carbon double bonds. The cyclic ketone may also be substituted or not by one or more substituents as defined above.

The term "amine" refers to hydrocarbons comprising at least one or more amine functional groups -NR ^c R ^d in which R ^c and R ^d are as defined above, R ^c and R ^d being able to be linked together to form with the nitrogen atom to which they are attached an aromatic or non-aromatic heterocycle comprising 4 to 10 members.

The term "esters" refers to compounds of formula R ^c -C(O)-OR ^d in which R ^c and R ^d are as defined above, R ^c and R ^d being able to be linked together to form with the ester group has a cycle comprising 4 to 20 carbon atoms.

The term "ether" refers to compounds of formula R ^c -OR ^d in which R ^c and R ^d are as defined above, R ^c and R ^d being able to be linked together to form with the atom of oxygen to which they are attached a heterocycle comprising 4 to 20 carbon atoms.

The term "aldehyde" refers to compounds comprising at least one or more -C(O)-H functional groups.

The term “nitrile” refers to compounds comprising at least one or more -CN functional groups.

The term “carbonate” refers to compounds of formula R ^c -OC(O)-OR ^d in which R ^c and R ^d are as defined above.

The term “thioalkyl” relates to compounds of formula R ^c SR ^d in which R ^c and R ^d are as defined above.

The term "phosphate" refers to compounds of formula P(OR ^C )3 in which R ^c is, independently for each substituent, as defined above.

The term "sulfate" refers to compounds of formula SO ₂ (OR ^C )2 in which R ^c is, independently for each substituent, as defined above.

The term "acid" refers to compounds of formula R ^C -CC>2H in which R ^c is as defined above. The term “amide” relates to compounds of formula R ^c C(O)NR ^e R ^d in which R ^c and R ^d are as defined above, R ^e having the same definition as R ^c , R ^c and R ^d which can be linked together to form, with the amide group -C(O)N- to which they are attached, a cyclic amide comprising from 4 to 10 members, preferably from 4 to 7 members. The cyclic amide may also include one or more carbon-carbon double bonds. The cyclic amide may also be substituted or not by one or more substituents as defined above.

The term “heterocycle” designates a carbon ring comprising 4 to 10 members of which at least one of the members is a heteroatom selected from the group consisting of O, S, P and N. The heterocycle may comprise one or more carbon-double bonds. carbon or one or more carbon-heteroatom double bonds or one or more heteroatom-heteroatom double bonds. Preferably, the heterocycle may comprise 1, 2, 3, 4 or 5 heteroatoms as defined above. In particular, the heterocycle may comprise 1, 2 or 3 heteroatoms selected from oxygen, nitrogen or sulfur. Preferably, the heterocycle may be a carbon ring comprising from 4 to 6 members of which 1, 2 or 3 members are heteroatoms selected from O or N. The heterocycle may or may not be substituted by one or more selected substituent(s). (s) among -OH, halogen, -NR ^a C(O)R ^b , -C(O)NR ^a R ^b -CN, -NO ₂ , -NR ^a R ^b , -OR ^a , -SR ^a , - CO ₂ R ^a , -OC(O)OR ^a , -OC(O)R ^a , -C(O)H, -C(O)R ^a in which R ^a and R ^b are as defined above.

The term “azeotropic composition” designates a liquid mixture of two or more compounds behaving like a single substance, and which boils at a fixed temperature while keeping a composition in the liquid phase identical to that of the gas phase. The term "quasi-azeotropic composition" means a liquid mixture of two or more compounds having a constant boiling point or which tends not to fractionate when subjected to boiling or evaporation.

The term “organic extractant” refers to a compound comprising at least one carbon atom.

According to a preferred embodiment, said organic extraction agent is a compound comprising from 2 to 12 carbon atoms, advantageously from 2 to 11 carbon atoms, preferably from 2 to 10 carbon atoms, more preferably from 2 to 9 carbon atoms, in particular 2 to 8 carbon atoms.

Said organic extraction agent preferably has a molecular mass of less than 200 g.mol' ¹ , advantageously less than 190 g.mol ¹ , preferably less than 180 g.mol ¹ , more preferably less than 170 g.mol ¹ , in particular less than 160 g.mol ¹ .

According to a preferred embodiment, said organic extractant has a melting point lower than 50°C, advantageously lower than 40°C, preferably lower than 30°C, more preferably less than 20°C, in particular less than 10°C, more particularly less than 0°C.

According to a preferred embodiment, said organic extractant has a separation factor Si, ₂ greater than or equal to 2.0, said separation factor being calculated by the formula Si, 2 = (yi,s)/(y2 ,s) in which yi,s represents the activity coefficient of chlorotrifluoroethylene in said organic extractant at infinite dilution, 72, s represents the activity coefficient of 1,1,2-trifluoroethane in said extractant organic at infinite dilution,

Advantageously, the separation factor Si, 2 is greater than or equal to 2.1, preferably greater than or equal to 2.2, more preferably greater than or equal to 2.3, in particular greater than or equal to 2.4, more particularly greater than or equal to 2.5.

According to a preferred embodiment, said organic extraction agent is selected from the group consisting of ethylchloroacetate, ethylmercaptoacetate, phenylacetate, n-butylacetate, b-phenylethylacetate, sec-butylacetate, methyldichloroacetate, isoamylacetate, n-pentylacetate, propynol, 3- butyn-l-ol, 2-butyn-l-ol, 3-butyn-2-ol, ethanol, 2-propanol, alpha-methylcyclopropanemethanol, glycidylaldehyde, 2,4-hexadienal, 3-phenyl-2-propenal, benzaldehyde, 4-methylbenzaldehyde, hexanal, heptanal, 3-butenoic acid, propionic acid, 4-pentenoic acid, 5-hexenoic acid, isobutyric acid, butyric acid, 4- ethylnitrobenzene, l,4-dimethyl-2-nitrobenzene, dimethylformamide, n, n-dimethylacetamide, methylformamide, n,n-dimethylpropanamide, n,n-dimethylbutanamide, n-butylacetamide, n-nitrosodimethylamine, 1-methylimidazol, n-(2-aminoethyl)-l,2-ethanediamine, tetramethylurea, 3,3' -iminodipropylamine, 2,2-diethoxyethanamine, tetraethylenepentamine, furfurylamine, n,n-dimethyl-l,3-benzenediamine, 4-morpholinepropanamine, 3-chlorobenzeneamine, acetic acid anhydride, propanoic acid anhydride, l isobutyric acid, butanoic acid anhydride, nitromethane, nitroethane, 1,3-dioxane, 4-methyl-l,3-dioxane, beta- propiolactone, gamma-butyrolactone, dimethylmalonate, ethyl acetoacetate, 1,2- ethanedioldiacetate, cyanoacetic acid methyl ester, 3-oxobutanoic acid 2-propenyl ester, pentanedioic acid dimethyl ester, ethyloxalate, 3-oxobutanoic acid methyl ethyl ester, ethylene glycol monomethylether acetate, dimethylmaleate, ethyl ester cyanoacetic acid, ethyl methyl ester of butanedioic acid, diethylmalonate, methyl 2-hydroxy-propanoic acid, t-butylacetoacetate, ethylsuccinate, ethyl ester of chloroacetic acid, allylidene diacetate, diethyl ester adipic acid, ethyl phenylacetate, phenyl methyl ester, acetic acid ester (z)-2-butenedioic acid dibutyl, acetic acid 2-methylpropyl ester, butanoic acid 2-propenyl ester, methyl benzoate, silicic acid tetramethyl ester, butanoic acid butyl ester 2-propenoic acid, 2-methylpropyl ester of propenoic acid, pentyl ester of formic acid, cyclohexyl ester of acetic acid, ethyl ester of 3-methylbutanoic acid, ethyl benzoate, methyl hexanoate, diglyme, bis(2- chloroethyl)ether, crotyl glycol ether, ethylene glycol monobenzylether, diethylene glycol monobutylether, 2-chloroethylethylether, diethylene glycol dibutylether, benzylmethylether, isoamylformate, 2,5,8,11-tetraoxadodecane, methylthiocyanate, ethylthiocyanate, ethylisothiocyanate, l -hydroxy-2-propanone, acetonylacetone, acetylacetone, 2-oxepanone, chloroacetone, n-methyl-2-pyrrolidinone, 5-ethyldihydro-2(3h)-furanone, l-bromo-2-propanone, 5-methyl-2( 3h)-furanone, 2-cyclohexen-l-one, l-(4-methoxyphenyl)-2-propanone, cyclopentanone, 4-oh-4-me-2-pentanone, 4-methylene-2-oxetanone, 1-cyclopropylethanone , 1- phenyl-2-propanone, 2,3-pentanedione, isophorone, cyclohexanone, 2-methylcyclopentanone, 4- methyl-3-penten-2-one, cycloheptanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 2,3- hexanedione , 3,4-hexanedione, 4-phenyl-2-butanone, 2-hexanone, l-(3,4-dimethylphenyl)ethanone, 4-methyl-2-pentanone, 3-hexanone, 4-fluoroacetophenone, 4,4- dimethyl-2-pentanone, 5-methyl-2-hexanone, 2,2-dimethylcyclohexanone, 2-heptanone, 2,4- dimethyl-3-pentanone, 2,2-dimethyl-3-pentanone, 3-heptanone, 4- heptanone, 2-octanone, 2- methyl-l-phenyl-l-propanone, (ethylthio) acetic acid, 1,3-propanedithiol, 1,2-ethanedithiol, 1,3- dithiolane, 1,4-butanedithiol, pentanedinitrile, 2-methylpentanedinitrile, hydroxyacetonitrile, 3- chloropropanenitrile, 2-hydroxypropanenitrile, dimethylaminopropionitrile, (e)-2-butenenitrile, 3- butenenitrile, butyronitrile, 2-hydroxy-2-methylpropanenitrile, valeronitrile, phenylacetonitrile, hexanenitrile, benzenepropanenitrile, benzonitrile, heptanenitrile, 3-methylbenzonitrile, 2- methylbenzonitrile, octanenitrile, 3-fluorobenzonitrile, nonanonitrile, trimethylphosphate, propylene carbonate, tetramethylorthocarbonate, triethylphosphate, dimethylsulfate, tris(2- butoxyethyl)phosphate, diethylsulfate, diethylcarbonate, 2-(2-ethoxyethoxy)ethanolacetate, 2- ethoxyethanolacetate, 2-(2-butoxyethoxy)ethanolacetate, 2-butoxyethanolacetate, furfural, diethyleneglycolmonoethylether, 2-methoxyethanol, 2-2-(2-butoxyethoxy)ethoxyethanol, 3- methoxy-l-butanol, l-methoxy2-propanol, ethoxyethanol, 2-furanmethanol, tetrahydro-2h-pyran-2-methanol, 3-methoxyphenol, l-propoxy-2-propanol, difluoroacetic acid, 2-fluoroethanol, 2-bromoethanolacetate, 2-chloroethanol, chlorosulfonic acid, 2,2-difluoroethanol, 2, 2,3,3- tetraflouro-l-propanol, 2-chloropropionic acid, l-chloro-2-methyl-2-propanol, 2,2'-oxybis(2,l-ethanediyloxy)bisethanol, 2,2' -(methylimino)bis-ethanol, 2-(2-methoxyethoxy)ethanol, 2- bromoethanol, 3-chloro-l-propanol, 1,3-dichloro-2-propanol, ethylenecyanohydrin, 2- nitroethanol, 2-nitro-l-butanol, 2-amino-l-butanol, 3-pyridinemethanol, 2-(ethylamino)ethanol, 2-(dimethylamino)-ethanol, 3-(dimethylamino)-l-propanol, l-( dimethylamino)-2-propanol, divinylsulfone, 2,2'-thiobisethanol, 2-(ethylthio)-ethanol, glycol, triethyleneglycol, diethyleneglycol, 1,3-propanediol, propyleneglycol, tripropyleneglycol, 1,5-pentanediol, 2-methyl- 2,4-pentanediol, 2-ethoxyethylacrylate, ethyl butyrate, propyl propionate, ethylvalerate, n-butylpropionate, n-propylbutyrate, isobutylpropionate, isopropylbutyrate, diacetoxydimethylsilane, (3-chloropropyl)trimethoxy-silane, triethoxysilane, methylhydrazine, pyridazine, 2-methylpyridinel -oxide, 1-piperidinecarboxaldehyde, (chloromethyl)-oxirane, dimethylcarbamoylchloride, 4-pyridinecarboxaldehyde, 2-nitropropane, 1-acetylpiperidine, 1-nitropropane, 4-methoxybenzaldehyde, l,l'-oxybis-2-ethoxy-ethane, trimethylphosphite, tetrahydrofurfurylalcohol, 4-(2-hydroxyethyl)morpholine, 1,3-butanediol, 1,2-ethanedioldinitrate, 3-oxiranyl-7-oxabicyclo[4,l,0]heptane, dibutyloxalate, morpholine, ((1,1-dimethylethoxy )methyl)oxirane, 1,4-oxathiane, dimethoxytetrahydrofuran, triethylorthoformate,

3-chloropropanoylchloride, citral, pyrrole, allylacrylate, 3-methoxyaniline, 2-methylpyrazine, methylaminoacetaldehydedimethylacetal, (c-chloroethoxy)ethane, butyllactate, nitrocyclohexane,

4-fluorobenzaldehyde, methoxyacetylchloride, 2-propen-l-ol, 2-ethylbutyraldehyde, 2- fluorobenzaldehyde, 1,6-heptadiyne, 2-nitrotoluene, methyl-2-chloroacrylate, 2- furancarbonylchloride, salicylicaldehyde, 4,5-dihydro- 2-methylthiazole, l,4-difluoro-2-nitrobenzene, benzisoxazole, thiazole, m-fluoroaniline, l,4-dichloro-2-butyne, aniline, p-fluoroaniline, 1-methyl-lh-pyrrole, pyridine, 2, 4-dimethylbenzaldehyde, methacrylalcohol, 2,3- dichlorobutane, chloroacetylchloride, 1,3-dichloropropane, 1,5-dichloro-pentane, 2,6- dimethylmorpholine, myristicin, 2,3-dimethylpyrazine, 2-butanoneoxime, 2-ethylnitrobenzene. Advantageously, said organic extraction agent is selected from the group consisting of phenylacetate, n-butylacetate, b-phenylethylacetate, sec-butylacetate, isoamylacetate, n-pentylacetate, ethanol, 2-propanol, alpha-methylcyclopropanemethanol, dimethylformamide, n,n - dimethylacetamide, methylformamide, n,n-dimethylpropanamide, n,n-dimethylbutanamide, n-butylacetamide, 1,3-dioxane, 4-methyl-l,3-dioxane, beta-propiolactone, gamma-butyrolactone, dimethylmalonate, ethyl acetoacetate, 1,2-ethanedioldiacetate, cyanoacetic acid methyl ester, 3-oxobutanoic acid 2-propenyl ester, pentanedioic acid dimethyl ester, ethyloxalate, 3-oxobutanoic acid methyl ethyl ester, ethylene glycol monomethylether acetate, dimethylmaleate, cyanoacetic acid ethyl ester, butanedioic acid ethyl methyl ester, diethylmalonate, 2-hydroxy-propanoic acid methyl ester, t-butylacetoacetate, ethylsuccinate, chloroacetic acid ethyl ester , allylidene diacetate, adipic acid diethyl ester, ethyl phenylacetate, methyl phenyl acetic acid ester, (z)-2-butenedioic acid dibutyl ester, acetic acid 2-methylpropyl ester, butanoic acid 2-propenyl ester, methyl benzoate, acetic acid tetramethyl ester silicic acid, 2-propenoic acid butyl ester, 2-methylpropyl ester of propenoic acid, pentyl ester of formic acid, cyclohexyl ester of acetic acid, ethyl ester of 3-methylbutanoic acid, benzoate ethyl, methyl hexanoate, diglyme, bis(2-chloroethyl)ether, crotyl glycol ether, ethylene glycol monobenzylether, diethyleneglycol monobutylether, 2-chloroethylethylether, diethyleneglycol dibutylether, benzylmethylether, isoamylformate, 2,5,8,11-tetraoxadodecane, l-hydroxy-2-propanone, acetonylacetone, acetylacetone, 2-oxepanone, chloroacetone, n-methyl-2-pyrrolidinone, 5-ethyldihydro-2(3h)-furanone, l-bromo-2-propanone, 5-methyl-2 (3h)-furanone, 2-cyclohexen-l- one, l-(4-methoxyphenyl)-2-propanone, cyclopentanone, 4-oh-4-me-2-pentanone, 4-methylene-

2-oxetanone, 1-cyclopropylethanone, l-phenyl-2-propanone, 2,3-pentanedione, isophorone, cyclohexanone, 2-methylcyclopentanone, 4-methyl-3-penten-2-one, cycloheptanone, 3-methylcyclohexanone, 4- methylcyclohexanone, 2,3-hexanedione, 3,4-hexanedione, 4-phenyl-2-butanone, 2-hexanone, l-(3,4-dimethylphenyl)ethanone, 4-methyl-2-pentanone, 3-hexanone, 4 - fluoroacetophenone, 4,4-dimethyl-2-pentanone, 5-methyl-2-hexanone, 2,2-dimethylcyclohexanone, 2-heptanone, 2,4-dimethyl-3-pentanone, 2,2-dimethyl-3-pentanone ,

3-heptanone, 4-heptanone, 2-octanone, 2-methyl-l-phenyl-l-propanone, pentanedinitrile, 2- methylpentanedinitrile, hydroxyacetonitrile, 2-hydroxypropanenitrile, dimethylaminopropionitrile, (e)-2-butenenitrile, 3-butenenitrile, butyronitrile, 2-hydroxy-2-methylpropanenitrile, valeronitrile, phenylacetonitrile, hexanenitrile, heptanenitrile, octanenitrile, 3-fluorobenzonitrile, nonanonitrile, trimethylphosphate, propylene carbonate, tetramethylorthocarbonate, triethylphosphate, dimethyl sulfate, tris(2-butoxyethyl)phosphate, diethyl sulfate, diethylcarbonate, 2 -(2- ethoxyethoxy)ethanolacetate, 2-ethoxyethanolacetate, 2-(2-butoxyethoxy)ethanolacetate, 2- butoxyethanolacetate, furfural, diethyleneglycolmonoethylether, 2-methoxyethanol, 2-2-(2- butoxyethoxy)ethoxyethanol, 3-methoxy-l- butanol, l-methoxy2-propanol, ethoxyethanol, 2- furanmethanol, tetrahydro-2h-pyran-2-methanol, 3-methoxyphenol, l-propoxy-2-propanol, 2,2'- oxybis(2,l-ethanediyloxy)bisethanol , 2,2'-(methylimino)bis-ethanol, 2-(2-methoxyethoxy)ethanol, glycol, triethyleneglycol, diethyleneglycol, 1,3-propanediol, propyleneglycol, tripropyleneglycol, 1,5-pentanediol, 2-methyl-2, 4-pentanediol, 2-ethoxyethylacrylate, ethyl butyrate, propylpropionate, ethylvalerate, n-butylpropionate, n-propylbutyrate, isobutylpropionate, isopropyl butyrate, l,l'-oxybis-2-ethoxy-ethane, trimethylphosphite, tetrahydrofurfurylalcohol, 4- (2- hydroxyethyl)morpholine, 1,3-butanediol, 1,2-ethanedioldinitrate, 3-oxiranyl-7-oxabicyclo[4,l,0]heptane, dibutyloxalate, morpholine, ((l,l-dimethylethoxy)methyl)oxirane, dimethoxytetrahydrofuran, triethylorthoformate, citral, allylacrylate, butyllactate, nitrocyclohexane, 2-propen-l-ol, methacrylalcohol, 2,6-dimethylmorpholine, 2-butanoneoxime. Preferably, said organic extractant is selected from the group consisting of phenylacetate, n-butylacetate, b-phenylethylacetate, sec-butylacetate, isoamylacetate, n-pentylacetate, ethanol, 2-propanol, alpha-methylcyclopropanemethanol, dimethylformamide, n, n- dimethylacetamide, methylformamide, n,n-dimethylpropanamide, n,n-dimethylbutanamide, n-butylacetamide, 1,3-dioxane, 4-methyl-l,3-dioxane, beta-propiolactone, gamma-butyrolactone, dimethylmalonate, ethyl acetoacetate , 1,2-ethanedioldiacetate, cyanoacetic acid methyl ester, 3-oxobutanoic acid 2-propenyl ester, pentanedioic acid dimethyl ester, ethyloxalate, 3-oxobutanoic acid methyl ethyl ester, ethylene glycol monomethylether acetate, dimethylmaleate, cyanoacetic acid ethyl ester, butanedioic acid ethyl methyl ester, diethylmalonate, 2-hydroxy-propanoic acid methyl ester, t-butylacetoacetate, ethylsuccinate, allylidene diacetate, diethyl ester adipic acid, ethyl phenylacetate, phenyl methyl acetic acid ester, (z)-2-butenedioic acid dibutyl ester, 2-methylpropyl acetic acid ester, silicic acid tetramethyl ester , 2-propenoic acid butyl ester, 2-methylpropyl ester of propenoic acid, pentyl ester of formic acid, cyclohexyl ester of acetic acid, ethyl ester of 3-methylbutanoic acid, methyl hexanoate , diglyme, crotyl glycol ether, diethyleneglycol monobutylether, diethyleneglycol dibutylether, isoamylformate, 2,5,8,11- tetraoxadodecane, l-hydroxy-2-propanone, acetonylacetone, acetylacetone, 2-oxepanone, n- methyl-2-pyrrolidinone, 5 -ethyldihydro-2(3h)-furanone, 5-methyl-2(3h)-furanone, 2-cyclohexen-l-one, l-(4-methoxyphenyl)-2-propanone, cyclopentanone, 4-hydroxy-4-methyl -2-pentanone, 4- methylene-2-oxetanone, 1-cyclopropylethanone, 2,3-pentanedione, isophorone, cyclohexanone, 2-methylcyclopentanone, 4-methyl-3-penten-2-one, cycloheptanone, 3-methylcyclohexanone, 4 - methylcyclohexanone, 2,3-hexanedione, 3,4-hexanedione, 4-phenyl-2-butanone, 2-hexanone, 4-methyl-2-pentanone, 3-hexanone, 4-fluoroacetophenone, 4,4-dimethyl-2 -pentanone, 5-methyl-2- hexanone, 2,2-dimethylcyclohexanone, 2-heptanone, 2,4-dimethyl-3-pentanone, 2,2-dimethyl-3- pentanone, 3-heptanone, 4-heptanone, 2 -octanone, 2-methyl-l-phenyl-l-propanone, pentanedinitrile, 2-methylpentanedinitrile, hydroxyacetonitrile, 2-hydroxypropanenitrile, dimethylaminopropionitrile, (e)-2-butenenitrile, 3-butenenitrile, butyronitrile, 2-hydroxy-2-methylpropanenitrile , valeronitrile, phenylacetonitrile, hexanenitrile, heptanenitrile, octanenitrile, nonanonitrile, trimethylphosphate, propylene carbonate, tetramethylorthocarbonate, triethylphosphate, tris(2-butoxyethyl)phosphate, diethylcarbonate, 2-(2- ethoxyethoxy)ethanolacetate, 2-ethoxyethanolacetate, 2-(2- butoxyethoxy)ethanolacetate, 2- butoxyethanolacetate, furfural, diethyleneglycolmonoethylether, 2-methoxyethanol, 2-2-(2-butoxyethoxy)ethoxyethanol, 3-methoxy-l-butanol, l-methoxy2-propanol, ethoxyethanol, 2-furanmethanol, tetrahydro-2h-pyran-2-methanol , 3-methoxyphenol, l-propoxy-2-propanol, 2,2'- oxybis(2,l-ethanediyloxy)bisethanol, 2-(2-methoxyethoxy)ethanol, glycol, triethyleneglycol, diethyleneglycol, 1,3-propanediol, propyleneglycol , tripropylene glycol, 1,5-pentanediol, 2-methyl- 2,4-pentanediol, 2-ethoxyethylacrylate, ethyl butyrate, propyl propionate, ethylvalerate, n- butylpropionate, n-propylbutyrate, isobutylpropionate, isopropylbutyrate, l,l'-oxybis- 2-ethoxy-ethane, tetrahydrofurfurylalcohol, 4-(2-hydroxyethyl)morpholine, 1,3-butanediol, 1,2-ethanedioldinitrate, 3-oxiranyl-7-oxabicyclo[4,l,0]heptane, dibutyloxalate, ((1 ,1- dimethylethoxy)methyl)oxirane, dimethoxytetrahydrofuran, triethylorthoformate, citral, allylacrylate, butyllactate, 2-propen-l-ol, methacrylalcohol, 2-butanoneoxime.

More preferably, said organic extraction agent is selected from the group consisting of beta-propiolactone, gamma-butyrolactone, l-hydroxy-2-propanone, acetonylacetone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1,2-ethanedioldiacetate, glycol, ethyloxalat, 3-oxobutanoicacid-l- methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, triethyleneglycol, diethylmalonate, furfural, diethylene glycol, t-butylacetoacetate, ethylsuccinate,

2.3-pentanedione, tripropylene glycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3-methoxy-l-butanol, 4-methyl-3-penten-2-one, l-methoxy2-propanol, phenylacetate, cycloheptanone, 3-methylcyclohexanone , 4-methylcyclohexanone, 2,3-hexanedione, 3,4-hexanedione, citral, 1,5-pentanediol, diethylene glycol monobutylether, 4-phenyl-2-butanone, ethanol, n-butylacetate, 4-methyl-2-pentanone , 3-hexanone, 4,4-dimethyl-2-pentanone, 5-methyl-2-hexanone, 2,2-dimethylcyclohexanone and ethyl benzoate.

In particular, said organic extractant is selected from the group consisting of trimethylphosphate, ethylacetoacetate, glycol, ethyl oxalate, triethyleneglycol, diethylmalonate, diethyleneglycol, 1,3-propanediol, propylene glycol, 2-methoxyethanol, ethanol and ethylbenzoate. According to a preferred embodiment, step b) is carried out at a pressure of 1 to 10 bara, preferably 1 to 7 bara.

According to a preferred embodiment, said organic extractant has a melting point lower than 0°C, advantageously lower than -5°C, preferably lower than -10°C, in particular lower than -20°C.

According to a preferred embodiment, when step b) is carried out at a pressure of 3 to 6 bara, said organic extractant has a melting point below 0°C. This makes it possible to avoid the solidification of said extraction agent at the top of the distillation column. In this preferred embodiment, said organic extractant is as described above.

According to another preferred embodiment, when step b) is carried out at a pressure of 1 to 3 bara, said organic extractant has a melting point lower than -10°C, preferably -20°C. C, in particular -40°C. According to this other embodiment, said organic extraction agent is preferably selected from the group consisting of beta-propiolactone, gamma-butyrolactone, l-hydroxy-2-propanone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1, 2-ethanedioldiacetate, glycol, ethyloxalate, 3- oxobutanoicacid-l-methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, diethylmalonate, furfural, diethyleneglycol, t-butylacetoacetate, ethylsuccinate,

2.3-pentanedione, tripropylene glycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3- methoxy-l-butanol, 4-methyl-3-penten-2-one, l-methoxy-2-propanol, phenylacetate, cycloheptanone, 3- methylcyclohexanone, 4-methylcyclohexanone, 2,3-hexanedione, 3,4-hexanedione, citral, 1,5-pentanediol, diethyleneglycolmonobutylether, 4-phenyl-2-butanone, ethanol, n-butylacetate, 4-methyl-2-pentanone, 3-hexanone, 4,4-dimethyl-2-pentanone, 5-methyl-2-hexanone, 2,2-dimethylcyclohexanone and ethylbenzoate; preferably said organic extraction agent is selected from the group consisting of beta-propiolactone, gamma-butyrolactone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1,2-ethanedioldiacetate, ethyloxalate, 3-oxobutanoicacid-l-methylethylester, ethyleneglycolmonomethyletheracetate , triethylphosphate, diethylmalonate, furfural, t-butylacetoacetate, ethylsuccinate, 1,3-propanediol, cyclopentanone, propyleneglycol, 1-cyclopropylethanone, 2-methoxyethanol, 2,3-pentanedione, tripropyleneglycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3 -methoxy-l-butanol, 4-methyl-3-penten-2-one, l-methoxy2- propanol, phenylacetate, cycloheptanone, 3-methylcyclohexanone, 4-methylcyclohexanone, 2,3- hexanedione, diethyleneglycolmonobutylether, ethanol, n-butylacetate , 4-methyl-2-pentanone, 3-hexanone, 4,4-dimethyl-2-pentanone, 5-methyl-2-hexanone, 2,2-dimethylcyclohexanone and ethylbenzoate; in particular said organic extraction agent is selected from the group consisting of gamma-butyrolactone, trimethylphosphate, propylene carbonate, dimethylmalonate, ethylacetoacetate, ethyloxalate, ethylene glycol monomethylether acetate, triethylphosphate, diethylmalonate, cyclopentanone, propylene glycol, 1-cyclopropylethanone, 2- methoxyethanol, 2,3-pentanedione, diethylcarbonate, 1,3-butanediol, 3-methoxy-l-butanol, 4-methyl-3-penten-2-one, l-methoxy2-propanol, 3-methylcyclohexanone, 4-methylcyclohexanone, diethylene glycol monobutylether, ethanol, n-butylacetate, 4-methyl-2-pentanone, 3-hexanone, 4,4-dimethyl-2-pentanone and 5-methyl-2-hexanone.

Trifluoroethylene production process

According to a second aspect of the present invention, a process for producing trifluoroethylene is provided. Said process is carried out in a reactor equipped with a fixed catalytic bed comprising a catalyst.

Said method comprises the steps of:

C') implementation of the purification process according to the present invention from said stream B2. According to a preferred embodiment, the process is carried out continuously. According to a preferred embodiment, the hydrogen is in anhydrous form. According to a preferred embodiment, the chlorotrifluoroethylene is in anhydrous form. Implementing the processes according to the invention in the presence of hydrogen and/or anhydrous chlorotrifluoroethylene makes it possible to effectively increase the life of the catalyst and thus the overall productivity of the process. The term anhydrous refers to a mass water content of less than 1000 ppm, advantageously 500 ppm, preferably less than 200 ppm, in particular less than 100 ppm based on the total weight of the compound considered.

Catalyst

Preferably, the catalyst is based on a metal from columns 8 to 10 of the periodic table of elements. In particular, the catalyst is based on a metal selected from the group consisting of Pd, Pt, Rh, and Ru; preferably palladium.

Preferably, the catalyst is supported. The support is preferably selected from the group consisting of activated carbon, an aluminum-based support, calcium carbonate, and graphite. Preferably, the support is based on aluminum. In particular, the support is alumina. The alumina may be alpha alumina. Preferably, the alumina comprises at least 90% alpha alumina. It was observed that the conversion of the hydrogenolysis reaction was enhanced when the alumina is alpha alumina. Thus, the catalyst is more particularly palladium supported on alumina, advantageously palladium supported on alumina comprising at least 90% alpha alumina, preferably palladium supported on alpha alumina.

Preferably, palladium represents from 0.01% to 5% by weight based on the total weight of the catalyst, preferably from 0.1% to 2% by weight based on the total weight of the catalyst.

In particular, said catalyst comprises from 0.01% to 5% by weight of palladium supported on alumina, preferably the alumina comprises at least 90% alpha alumina, more preferably the alumina is alpha alumina.

Catalyst activation

Said catalyst is preferably activated before its use in step A'). Preferably, the activation of the catalyst is carried out at high temperature and in the presence of a reducing agent, an inert gas or a mixture thereof.

According to a particular embodiment, the reducing agent is chosen from the group consisting of hydrogen, carbon monoxide, nitrogen monoxide, formaldehyde, Ci-Cg alkanes and Ci-Cio hydrohalocarbons, or a mixture of these; preferably hydrogen or a Ci-Cio hydrohalocarbon, or a mixture thereof; in particular hydrogen, chlorotrifluoroethylene, trifluoroethylene, chlorotrifluoroethane, trifluoroethane or difluoroethane or a mixture thereof.

The inert gas can be nitrogen or argon; preferably nitrogen.

Preferably, the activation of the catalyst is carried out at a temperature between 100°C and 400°C, in particular at a temperature between 150°C and 350°C. In particular, the activation of the catalyst is carried out at a temperature between 100°C and 400°C, in particular at a temperature between 150°C and 350°C, in the presence of hydrogen as reducing agent.

Preferably, the temperature of the catalytic bed is increased during activation from a temperature Tl to a temperature T2. In particular, the temperature of the catalytic bed is increased from a temperature Tl to a temperature T2 greater than Tl with a temperature gradient less than 0.5°C/min. The temperature gradient implemented makes it possible to avoid early degradation of the catalyst and thus to allow better yield or better productivity of the hydrogenolysis reaction. In particular, the temperature is increased with a temperature gradient less than 0.45°C/min or less than 0.40°C/min, or less than 0.35°C/min, or less than 0.30° C/min, or less than 0.25°C/min, or less than 0.20°C/min, or less than 0.15°C/min, or less than 0.10°C/min, or less at 0.05°C/min. The temperature Tl represents the initial temperature of the activation step. This temperature Tl can be the ambient temperature. Alternatively, the temperature Tl can be between 0°C and 150°C, advantageously between 0°C and 120°C, preferably between 0°C and 100°C, more preferably between 10°C and 100°C, in particularly between 20°C and 100°C, more particularly between 20°C and 75°C, preferably between 20°C and 50°C. The temperature T2 represents the temperature to be reached during the activation phase. The temperature T2 is advantageously between 150°C and 400°C, preferably between 155°C and 375°C, more preferably between 160°C and 350°C, in particular between 165°C and 325°C, more particularly between 170°C and 320°C, preferably between 175°C and 310°C, more preferably between 180°C and 300°C. According to a preferred embodiment, the temperature T2 is advantageously between 185°C and 290°C, preferably between 190°C and 280°C, more preferably between 195°C and 270°C, in particular between 200°C and 260°C. The temperature T2 can be maintained from 5 min to 200 h, preferably from 10 min to 100 h, in particular from 15 min to 75 h, more particularly from 30 min to 50 h, preferably from 1 h to 25 h. The temperature T2 can be maintained from 5 min to 24 h, preferably from 10 min to 8 p.m., in particular from 15 min to 3 p.m., more particularly from 30 min to 1 Oh, preferably from 1 h to 1 Oh.

Preferably, the gas flow used during the activation step does not include oxygen. Preferably, the activation step can be carried out with a quantity of reducing agent greater than 0.01 mol per gram of catalyst, preferably greater than 0.05 per gram of catalyst. In particular, the activation step can be carried out with a quantity of reducing agent of between 0.01 and 10 mol per gram of catalyst, preferably between 0.05 and 5 mol per gram of catalyst.

According to another embodiment, during the activation step, the temperature of the catalytic bed is increased from a temperature Tl to a temperature T2 in steps. Activating the catalyst in stages makes the catalyst more efficient. The implementation of bearings makes it possible to avoid degradation of the catalyst. It was also observed that the properties of the catalyst were further improved if the rise in temperature between the levels is progressive and relatively slow compared to the usual conditions for activating a catalyst. Thus, preferably, at the activation step, between two levels, the temperature is increased with a temperature gradient of less than 0.5°C/min. The temperature gradient implemented between two levels makes it possible to avoid early degradation of the catalyst and thus to allow better yield or better productivity of the hydrogenolysis reaction. In particular, the temperature is increased with a temperature gradient less than 0.45°C/min or less than 0.40°C/min, or less than 0.35°C/min, or less than 0.30°C /min, or less than 0.25°C/min, or less than 0.20°C/min, or less than 0.15°C/min, or less than 0.10°C/min, or less than 0.05°C/min. The temperature Tl represents the initial temperature of the activation step. This temperature Tl can be the ambient temperature. Alternatively, the temperature Tl can be between 0°C and 150°C, advantageously between 0°C and 120°C, preferably between 0°C and 100°C, more preferably between 10°C and 100°C, in particularly between 20°C and 100°C, more particularly between 20°C and 75°C, preferably between 20°C and 50°C. The temperature T2 represents the temperature to be reached during the activation phase. The temperature T2 is advantageously between 150°C and 400°C, preferably between 155°C and 375°C, more preferably between 160°C and 350°C, in particular between 165°C and 325°C, more particularly between 170°C and 320°C, preferably between 175°C and 310°C, more preferably between 180°C and 300°C. According to a preferred embodiment, the temperature T2 is advantageously between 185°C and 290°C, preferably between 190°C and 280°C, more preferably between 195°C and 270°C, in particular between 200°C and 260°C. The temperature T2 can be maintained from 5 min to 200 h, preferably from 10 min to 100 h, in particular from 15 min to 75 h, more particularly from 30 min to 50 h, preferably from 1 h to 25 h. The temperature T2 can be maintained from 5 min to 24 h, preferably from 10 min to 8 p.m., in particular from 15 min to 3 p.m., more particularly from 30 min to 1 Oh, preferably from 1 h to 1 Oh. Step i') of activating the catalyst contains at least one stage between temperature Tl and temperature T2. Step i') of activating the catalyst may include several stages between temperature Tl and temperature T2. Preferably, the activation step comprises at least one level at a temperature Tla of between 90 and 120°C. The presence of a level between 90°C and 120°C is preferred to increase the lifespan of the catalyst. The activation step may also include one or more stages between the temperature Tl and Tla and/or between the temperature Tla and T2. Preferably, each level between temperature Tl and temperature T2 can last between 5 min and 200 h, preferably between 10 min and 100 h, in particular between 15 min and 75 h, more particularly between 30 min and 50 h. In particular, each level between temperature Tl and temperature T2 can last between 5 min and 24 hours, preferably between 10 min and 20 hours, in particular between 15 min and 15 hours, more particularly between 30 min and 1 Oh. In particular, the plateau at temperature Tla can last between 5 min and 200 h, preferably between 10 min and 100 h, in particular between 15 min and 75 h, more particularly between 30 min and 50 h. Preferably, the plateau at temperature Tla can last between 5 min and 24 hours, preferably between 10 min and 20 hours, in particular between 15 min and 15 hours, more particularly between 30 min and 1 Oh.

The gas flow used during the activation step may be different over time. For example, the gas flow may comprise an inert gas between two bearings and for example comprise a reducing agent between two other bearings. In particular, the gas flow includes an inert gas when the activation step is carried out between the temperature Tl and Tla and the gas flow comprises a reducing agent, preferably hydrogen or Ci-Cio hydrohalocarbons as defined above, when the The activation step is implemented between the temperature Tla and T2. Thus, the gas flow used during the activation step is modified during the stage implemented at temperature Tla. Alternatively, the gas flow may comprise a reducing agent such as hydrogen or Ci-Cio hydrohalocarbons as defined above throughout the activation step, optionally in mixture with an inert gas such as 'nitrogen. It has been observed that the use of a reducing agent such as hydrogen or Ci-Cio hydrohalocarbons as defined above, optionally in mixture with an inert gas such as nitrogen, during the rise in temperature between the temperature Tla of said bearing and the temperature T2 represents an additional advantage in terms of productivity. As mentioned above, the temperature T2 is maintained for a certain period of time. During this stage at temperature T2, the gas flow can be modified. Thus, the gas flow during the stage at temperature T2 may comprise hydrogen or a Ci-Cio hydrohalocarbon as defined above; in particular the gas flow during the stage at temperature T2 may comprise hydrogen, chlorotrifluoroethylene, trifluoroethane, trifluoroethylene, chlorotrifluoroethane or difluoroethane. Preferably, the activation step can be carried out with a quantity of reducing agent greater than 0.01 per gram of catalyst, preferably greater than 0.05 per gram of catalyst. In particular, the activation step can be carried out with a quantity of reducing agent of between 0.01 and 10 mol per gram of catalyst, preferably between 0.05 and 5 mol per gram of catalyst.

According to another embodiment, the activation step comprises bringing said catalyst into contact with a gas flow which comprises chlorotrifluoroethylene, and optionally hydrogen. It was noted that chlorotrifluoroethylene (CTFE) enabled the catalyst to be activated, particularly when hydrogen was also present. This allows an improvement in the trifluoroethylene production process. Activation in the presence of CTFE makes it possible to activate the catalyst at a lower temperature and therefore provides a process that consumes less energy. The process is further simplified since the reducing agent during activation is also one of the reactants for the subsequent reaction. Preferably, in this embodiment, the activation step is carried out at a temperature T2' lower than 100°C. This temperature T2' can be reached from a temperature Tl' using a low temperature gradient. Thus, during the activation step, the temperature of the catalytic bed is increased from a temperature Tl' to a temperature T2' greater than Tl', preferably the temperature of the catalytic bed is increased by a temperature Tl' at a temperature T2' greater than Tl' with a temperature gradient less than 0.5°C/min. The temperature gradient implemented makes it possible to avoid early degradation of the catalyst and thus to allow better yield or better productivity of the hydrogenolysis reaction. In particular, the temperature is increased with a temperature gradient less than 0.45°C/min or less than 0.40°C/min, or less than 0.35°C/min, or less than 0.30°C /min, or less than 0.25°C/min, or less than 0.20°C/min, or less than 0.15°C/min, or less than 0.10°C/min, or less than 0.05°C/min.

Preferably, the temperature of the catalytic bed is increased by increasing the contact time calculated as the ratio between the volume, in liters, of catalyst and the total flow rate of said gas flow, in normal liters per second, at the inlet. of the reactor. The contact time is between 1 and 60 seconds, preferably between 5 and 45 seconds, in particular between 10 and 30 seconds, more particularly between 15 and 25 seconds. The temperature Tl' can be between 0°C and 50°C, advantageously between 10°C and 50°C, preferably between 20°C and 50°C. Preferably, the temperature T2' is lower than the temperature T3 for implementing step A'). The temperature T3 is preferably between 100°C and 180°C, more preferably between 100°C and 160°C, in particular between 120°C and 160°C.

Catalyst regeneration

Said catalyst used in the present process can be regenerated. This regeneration step can be implemented in a temperature range of the catalytic bed between 90°C and 450°C. Preferably, the regeneration step is carried out in the presence of hydrogen. The implementation of the regeneration step makes it possible to improve the yield of the reaction compared to the initial yield before regeneration.

According to a preferred embodiment, the regeneration step can be carried out at a catalytic bed temperature of 90°C to 300°C, preferably at a catalytic bed temperature of 90°C to 250°C, more preferably from 90°C to 200°C, in particular from 90°C to 175°C, more particularly at a temperature of the catalytic bed of 90°C to 150°C. In particular, carrying out the regeneration step at a low temperature, for example from 90°C to 200°C or from 90°C to 175°C or from 90°C to 150°C, allows the desorption of compounds harmful to the activity of the catalyst and/or to limit phase transitions modifying the structure of the catalyst.

According to another preferred embodiment, the regeneration step can be carried out at a temperature of the catalytic bed greater than 200°C, advantageously greater than 230°C, preferably greater than 250°C, in particular greater than 300°C. °C. The regeneration step can be implemented periodically depending on the productivity or conversion obtained in the step has). The regeneration step can be carried out advantageously at a temperature of the catalytic bed between 200°C and 300°C, preferably between 205°C and 295°C, more preferably between 210°C and 290°C, in particularly between 215°C and 290°C, more particularly between 220°C and 285°C, preferably between 225°C and 280°C, more preferably between 230°C and 280°C. Alternatively, the regeneration step can be carried out at a temperature between 300°C and 450°C, preferably between 300°C and 400°C. The regenerated catalyst can be reused in step A') of the present process.

Hydrogenolysis reaction

The process comprises, as mentioned above, a reaction step of hydrogenolysis of chlorotrifluoroethylene with hydrogen to produce a stream comprising trifluoroethylene. The hydrogenolysis step is carried out in the presence of a catalyst and in the gas phase. Preferably, the hydrogenolysis step is carried out in the presence of a previously activated catalyst and in the gas phase. The hydrogenolysis step consists of simultaneously introducing hydrogen, CTFE and optionally an inert gas, such as nitrogen, in the gas phase and in the presence of said catalyst, preferably activated.

Preferably, said step A') is carried out at a fixed catalytic bed temperature of between 50°C and 250°C. Said step A') can be carried out at a temperature of the fixed catalytic bed of between 50°C and 240°C, advantageously between 50°C and 230°C, preferably between 50°C and 220°C, more preferably between 50°C and 210°C, in particular between 50°C and 200°C. Said step a) can also be implemented at a temperature of the fixed catalytic bed of between 60°C and 250°C, advantageously between 70°C and 250°C, preferably between 80°C and 250°C, more preferably between 90°C and 250°C, in particular between 100°C and 250°C, more particularly between 120°C and 250°C. Said step A') can also be implemented at a temperature of the fixed catalytic bed of between 60°C and 240°C, advantageously between 70°C and 230°C, preferably between 80°C and 220°C, more preferably between 90°C and 210°C, in particular between 100°C and 200°C, more particularly between 100°C and 180°C, preferably between 100°C and 160°C, particularly preferably between 120°C °C and 160°C.

The H2/CTFE molar ratio is between 0.5/1 to 2/1 and preferably between 1/1 to 1.2/1. If an inert gas such as nitrogen is present in step A'), the nitrogen/Fh molar ratio is between 0/1 to 2/1 and preferably between 0/1 to 1/1.

Step A') is preferably carried out at a pressure of 0.05 MPa to 1.1 MPa, more preferably from 0.05 MPa to 0.5 MPa, in particular at atmospheric pressure. The contact time calculated as the ratio between the volume, in liters, of catalyst and the total flow rate of the gas mixture, in normal liters per second, at the reactor inlet, is between 1 and 60 seconds, preferably between 5 and 45 seconds, particularly between 10 and 30 seconds, more particularly between 15 and 25 seconds.

Examples

Method for selection of organic extractant

The selection of the organic extraction agent is determined by the use of the Cosmo-RS model implemented in the COSMOTHERM software. For this selected binary pair, a separation factor is calculated for each of the solvents studied by the following equation:

If, 2 = (YI,S)/(Y2,S) in which

Yi,s represents the activity coefficient of the first compound 1 in the organic extraction agent considered at infinite dilution,

Y2,S represents the activity coefficient of the second compound 2 of the binary couple in the organic extraction agent considered at infinite dilution,

An absorption capacity is also calculated for each of the solvents studied and for a binary couple (1,2) considered. The absorption capacity is calculated by the formula C2,s = l/(Y2,s) in which Y2,s represents the activity coefficient of the second compound of the binary couple considered in said organic extraction agent studied at infinite dilution .

The calculations are repeated for each organic extractant studied. Minimum separation factor and absorption capacity values are identified in order to allow sufficient separation between the first compound and the second compound of the binary pair (1,2) considered.

Example 1

In this example, the separation between chlorotrifluoroethylene (CTFE) and 1,1,2-trifluoroethane is considered. Organic extraction agents having a separation factor Si, ₂ greater than 2 are capable of separating a mixture comprising chlorotrifluoroethylene (CTFE) and 1,1,2-trifluoroethane.

[Table 1]

Table 1 - Capacity and Separation Factor of the organic extractant

The results are confirmed from a mixture comprising 90-95% by weight of chlorotrifluoroethylene and 5-10% by weight of 1,1,2-trifluoroethane based on the total weight of the mixture. This is distilled under 1 bara with one of the following extraction agents: glycol, 1,3-propanediol, propylene glycol or ethanol. The mixture to be separated is introduced into a distillation column at atmospheric pressure. The extractant is introduced continuously at the top of the distillation column. The chlorotrifluoroethylene is recovered at the top of the distillation column. The 1,1,2-trifluoroethane and the extraction agent are recovered at the bottom of the distillation column.

Claims

1. Process for purifying chlorotrifluoroethylene (CTFE) from a first composition comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane (143), said process comprising the steps of: a) Extractive distillation of said first composition in the presence at least one organic extractant to form i) a second composition comprising said organic extractant and 1,1,2-trifluoroethane; and ii) a first stream comprising chlorotrifluoroethylene, b) recovery and separation of said second composition to form a second stream comprising said organic extractant and a third stream comprising 1,1,2-trifluoroethane, preferably said second stream is recycled to step a).

2. Method according to the preceding claim characterized in that said organic extraction agent has a flash point greater than 13°C.

3. Method according to any one of the preceding claims characterized in that said organic extraction agent is a compound comprising from 2 to 12 carbon atoms.

4. Method according to any one of the preceding claims, characterized in that said organic extraction agent has a molecular mass of less than 200 g. mol ¹ .

5. Method according to any one of the preceding claims characterized in that said organic extraction agent has a separation factor Si, 2 greater than or equal to 2.0, said separation factor being calculated by the formula Si, ₂ = (yi,s)/(y2,s) in which yi,s represents the activity coefficient of chlorotrifluoroethylene in said organic extractant at infinite dilution, y ₂ ,s represents the activity coefficient of 1.1, 2-trifluoroethane in said organic extraction agent at infinite dilution, advantageously the separation factor S _li2 is greater than or equal to 2.1, preferably greater than or equal to 2.2, more preferably greater than or equal to 2.3, in particular greater than or equal to 2.4, more particularly greater than or equal to 2.5. Tl

6. Method according to any one of the preceding claims characterized in that said organic extraction agent has an absorption capacity C2,s greater than or equal to 0.20, said absorption capacity being calculated by the formula C ₂ , _s = l/(y2,s) in which y ₂ ,s represents the activity coefficient of 1,1,2-trifluoroethane in said organic extractant at infinite dilution.

7. Method according to any one of the preceding claims, characterized in that the first composition is an azeotropic or quasi-azeotropic composition comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane.

8. Method according to any one of the preceding claims characterized in that said organic extractant has a melting point below 0°C.

9. Method according to any one of the preceding claims, characterized in that step b) is carried out at a pressure of 1 to 10 bara, preferably 1 to 7 bara.

10. Method according to any one of the preceding claims characterized in that said organic extraction agent is selected from the group consisting of H ₂ O, beta-propiolactone, gamma-butyrolactone, l-hydroxy-2-propanone, acetonylacetone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1,2-ethanedioldiacetate, glycol, ethyloxalat, 3-oxobutanoicacid-l- methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, triethyleneglycol, diethylmalonate, furfural, diethyleneglycol, t-butylacetoacetate, ethylsuccinate, 1, 3-propanediol, cyclopentanone, propylene glycol, 1- cyclopropylethanone, 2-methoxyethanol, 2,3-pentanedione, tripropylene glycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3-methoxy-l-butanol, 4-methyl-3- penten- 2-one, l-methoxy2-propanol, phenylacetate, cycloheptanone, 3- methylcyclohexanone, 4-methylcyclohexanone, 2,3-hexanedione, 3,4-hexanedione, citral, 1,5-pentanediol, diethyleneglycolmonobutylether, 4-phenyl-2- butanone, ethanol, n-butylacetate, 4-methyl-2-pentanone, 3-hexanone, 4,4-dimethyl-2-pentanone, 5-methyl-2-hexanone, 2,2-dimethylcyclohexanone and ethyl benzoate. Process for producing trifluoroethylene in a reactor provided with a fixed catalytic bed comprising a catalyst, said process comprising the steps of:

C') implementation of the purification process according to any one of preceding claims 1 to 10 from said current B2.