FR3142187A1 - Process for purifying chlorotrifluoroethylene by extractive distillation - Google Patents

Abstract

The present invention relates to 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).

Description

Process for the purification of chlorotrifluoroethylene by extractive distillation

The present invention relates to a process for the production and purification of hydrofluoroolefins. In particular, the present invention relates to a process for the purification of chlorotrifluoroethylene. The present invention also relates to a process for the production of 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 co-monomers for the manufacture of fluorocarbon polymers with 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 explosive limit (LEL) of approximately 10% and an upper explosive 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 above main risks, 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 as starting materials chlorotrifluoroethylene (CTFE) and hydrogen in the presence of a catalyst and in the gas phase. WO 2013/128102 discloses a process for producing trifluoroethylene by hydrogenolysis of CTFE in the gas phase and in the presence of a catalyst based on a group VIII metal 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 therefore a need for a process for purifying chlorotrifluoroethylene.

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:

1. une seconde composition comprenant ledit agent d’extraction organique et le 1,1,2-trifluoroéthane ; et
2. un premier courant comprenant le chlorotrifluoroéthylène, et

a) Extractive distillation of said first composition in the presence of at least one organic extraction agent to form

1. a second composition comprising said organic extractant and 1,1,2-trifluoroethane; and
2. a first stream comprising chlorotrifluoroethylene, and

b) Recovery and separation of said second composition to form a second stream comprising said organic extraction agent and a third stream comprising 1,1,2-trifluoroethane, preferably said second stream is recycled to step a).

According to a preferred embodiment, said organic extracting agent 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 S _1,2 greater than or equal to 2.0, said separation factor being calculated by the formula S _1,2 = (γ _1,S )/(γ _2,S ) in which

γ _1,S represents the activity coefficient of chlorotrifluoroethylene in said organic extractant at infinite dilution,

γ _2,S represents the activity coefficient of 1,1,2-trifluoroethane in said organic extractant at infinite dilution,

advantageously, the separation factor S _1.2 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 C _2,S = 1/(γ _2,S ) in which γ _2,S represents the activity coefficient of 1,1,2-trifluoroethane in said organic extraction agent 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 extracting agent has a melting point below 0°C.

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

According to a preferred embodiment, said organic extraction agent is selected from the group consisting of beta-propiolactone, gamma-butyrolactone, 1-hydroxy-2-propanone, acetonylacetone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1, 2-ethanedioldiacetate, glycol, ethyloxalat, 3-oxobutanoicacid-1-methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, triethyleneglycol, diethylmalonate, furfural, diethyleneglycol, t-butylacetoacetate, ethylsuccinate, 1,3-propanediol, cyclopentanone, propyleneglycol, 1-cyclopropylethanone, 2-methoxyethanol, 2,3-pentanedione, tripropylene glycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3-methoxy-1-butanol, 4-methyl-3-penten-2-one, 1-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 B 1 comprising trifluoroethylene and a stream B 2 comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane,

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

Detailed description of the invention CTFE purification 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 when carrying out the processes for producing trifluoroethylene. 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 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:

1. une seconde composition comprenant ledit agent d’extraction organique et le 1,1,2-trifluoroéthane ; et
2. un premier courant comprenant le chlorotrifluoroéthylène,

a) Extractive distillation of said first composition in the presence of at least one organic extraction agent to form

1. a second composition comprising said organic extractant and 1,1,2-trifluoroethane; and
2. a first stream comprising chlorotrifluoroethylene,

b) Recovery and separation of said second composition to form a second stream comprising said organic extraction agent 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 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 between -40°C and 40°C at a pressure between 0.5 bara and 8 bara. More particularly, said first composition is azeotropic and has a boiling point between -35°C and 25°C at a pressure between 1 bara and 6 bara.

Thus, said first composition is azeotropic and may 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 of between -40°C and 40°C at a pressure of 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 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 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 of between -30°C and 25°C at a pressure of between 1 bara and 6 bara.

According to a preferred embodiment, said organic extracting agent is a solvent selected 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 extracting 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 C 1 -C 2 alkane compounds.₁-C₂₀, C cycloalkane₃-C_{2 0}, C alkene₅-C_{2 0}, C cycloalkene₅-C_{2 0}, arena in C₆-C_{1 8}. For example, the term alkane refers to compounds of formula C_nH_2n+2in which n is between 1 and 20. The term C alkane₁-C₂₀ includes for example pentane, hexane, heptane, octane, nonane, decane or isomers thereof. The term C alkene₅-C_{2 0}refers to hydrocarbon compounds comprising one or more carbon-carbon double bonds and comprising from 5 to 20 carbon atoms. The term C cycloalkane₃-C_{2 0}refers to a saturated hydrocarbon ring comprising 3 to 20 carbon atoms. The term C aryl₆-C_{1 8} refers to cyclic and aromatic hydrocarbon compounds containing 6 to 18 carbon atoms. The term C cycloalkene₅-C_{2 0}refers to cyclic hydrocarbon compounds having from 5 to 20 carbon atoms and comprising one or more carbon-carbon double bonds.

The term "alkyl" denotes a monovalent radical derived from an alkane, linear or branched, comprising from 1 to 20 carbon atoms. The term "cycloalkyl" denotes a monovalent radical derived from a cycloalkane comprising from 3 to 20 carbon atoms. The term "aryl" denotes a monovalent radical derived from an arene comprising from 6 to 18 carbon atoms. The term "alkenyl" denotes a monovalent radical of 2 to 20 carbon atoms and at least one carbon-carbon double bond. The term "alkynyl" denotes a monovalent radical of 2 to 20 carbon atoms and at least one carbon-carbon triple bond. The term "halogen" refers to a -F, -Cl, -Br or -I group. The term "cycloalkenyl" refers to a monovalent radical derived from a cycloalkene comprising from 3 to 20 carbon atoms. The C ₁ -C ₂₀ alkyl, C ₂ -C ₂₀ alkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkyl, C ₃ -C ₂₀ cycloalkenyl, C ₆ -C _{1 8} aryl substituents may be unsubstituted or substituted by one or more substituents -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 , wherein R ^a and R ^b are independently of each other hydrogen, unsubstituted C ₁ -C ₂₀ alkyl, C ₂ alkenyl -C ₂₀ unsubstituted, C ₂ -C ₂₀ unsubstituted alkynyl, C ₃ -C ₂₀ unsubstituted cycloalkyl, C ₃ -C ₂₀ unsubstituted cycloalkenyl, C ₆ -C _{1 8} unsubstituted aryl. In the substituents -NR ^a R ^b , R ^a and R ^b can form with the nitrogen atom to which they are attached a saturated or unsaturated, aromatic or unaromatic heterocycle comprising from 5 to 10 members.

The term "hydrohalocarbons" refers to compounds of the formula R ^a X wherein R ^a is selected from C ₁ -C ₂₀ alkyl, C ₂ -C ₂₀ alkenyl, C ₂ -C ₂₀ alkynyl, C _{3 -C 20 cycloalkyl, C 3 -C 20 cycloalkenyl} , C ₆ -C _{1 8} aryl and X represents a chlorine, fluorine, bromine or iodine atom. The C ₁ -C ₂₀ alkyl, C ₂ -C ₂₀ alkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkyl, C ₃ -C ₂₀ cycloalkenyl, C ₆ -C _{1 8} aryl substituents may be substituted or not by one or more substituents -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 , wherein 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 a hydroxyl group -OH.

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 C ₁ -C ₂₀ alkyl, C ₂ -C ₂₀ alkenyl, C ₂ -C ₂₀ alkynyl, C ₃ -C ₂₀ cycloalkyl, C ₃ -C ₂₀ cycloalkenyl, C ₆ -C _{1 8} aryl and may be substituted or not by one or more substituents -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, 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 can also comprise one or more carbon-carbon double bonds. The cyclic ketone can 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 from 4 to 10 links.

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 a cycle comprising from 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 oxygen atom to which they are attached a heterocycle comprising from 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 the 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 the 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 the 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 the formula R ^c -CO ₂ H 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 being able to 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 comprise 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" means a carbon ring comprising from 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-carbon double bonds 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 substituent(s) selected from -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" means a liquid mixture of two or more compounds that behave as a single substance and that boils at a fixed temperature while maintaining a liquid phase composition identical to that of the gas phase. The term "quasi-azeotropic composition" means a liquid mixture of two or more compounds that has a constant boiling point or that tends not to fractionate when subjected to boiling or evaporation.

The term “organic extractant” refers to a compound containing 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 from 2 to 8 carbon atoms.

Said organic extracting 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 extraction agent has a melting point of less than 50°C, advantageously less than 40°C, preferably less 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 S _1,2 greater than or equal to 2.0, said separation factor being calculated by the formula S _1,2 = (γ _1,S )/(γ _2,S ) in which

γ _1,S represents the activity coefficient of chlorotrifluoroethylene in said organic extractant at infinite dilution,

γ _2,S represents the activity coefficient of 1,1,2-trifluoroethane in said organic extractant at infinite dilution,

Advantageously, the separation factor S _1.2 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 extracting agent is selected from the group consisting of ethylchloroacetate, ethylmercaptoacetate, phenylacetate, n-butylacetate, b-phenylethylacetate, sec-butylacetate, methyldichloroacetate, isoamylacetate, n-pentylacetate, propynol, 3-butyn-1-ol, 2-butyn-1-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, 1,4-dimethyl-2-nitrobenzene, dimethylformamide, n,n-dimethylacetamide, methylformamide, n,n-dimethylpropanamide, n,n-dimethylbutanamide, n-butylacetamide, n-nitrosodimethylamine, 1-methylimidazol, n-(2-aminoethyl)-1,2-ethanediamine, tetramethylurea, 3,3'-iminodipropylamine, 2,2-diethoxyethanamine, tetraethylenepentamine, furfurylamine, n,n-dimethyl-1,3-benzenediamine, 4-morpholinepropanamine, 3-chlorobenzeneamine, acetic acid anhydride, propanoic acid anhydride, isobutyric acid anhydride, butanoic acid anhydride, nitromethane, nitroethane, 1,3-dioxane, 4-methyl-1,3-dioxane, beta-propiolactone, gamma-butyrolactone, dimethylmalonate, ethyl acetoacetate, 1,2-ethanedioldiacetate, cyanoacetic acid methyl ester, 2-propenyl ester of 3-oxobutanoic acid, pentanedioic acid dimethyl ester, ethyloxalate, methyl ethyl ester of 3-oxobutanoic acid, ethylene glycol monomethylether acetate, dimethylmaleate, cyanoacetic acid ethyl ester, ethyl methyl ester of butanedioic acid, diethylmalonate, 2-hydroxypropanoic acid methyl acid, t-butylacetoacetate, ethylsuccinate, chloroacetic acid ethyl ester, allylidene diacetate, adipic acid diethyl ester, phenylacetate ethyl, phenyl methyl ester of acetic acid, dibutyl ester of (z)-2-butenedioic acid, 2-methylpropyl ester of acetic acid, 2-propenyl ester of butanoic acid, methyl benzoate, tetramethyl ester of silicic acid, butyl ester of 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, 1-hydroxy-2-propanone, acetonylacetone, acetylacetone, 2-oxepanone, chloroacetone, n-methyl-2-pyrrolidinone, 5-ethyldihydro-2(3h)-furanone, 1-bromo-2-propanone, 5-methyl-2(3h)-furanone, 2-cyclohexen-1-one, 1-(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, 1-(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-1-phenyl-1-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-1-butanol, 1-methoxy2-propanol, ethoxyethanol, 2-furanmethanol, tetrahydro-2h-pyran-2-methanol, 3-methoxyphenol, 1-propoxy-2-propanol, difluoroacetic acid, 2-fluoroethanol, 2-bromoethanolacetate, 2-chloroethanol, chlorosulfonic acid, 2,2-difluoroethanol, 2,2,3,3-tetraflouro-1-propanol, 2-chloropropionic acid, 1-chloro-2-methyl-2-propanol, 2,2'-oxybis(2,1-ethanediyloxy)bisethanol, 2,2'-(methylimino)bis-ethanol, 2-(2-methoxyethoxy)ethanol, 2-bromoethanol, 3-chloro-1-propanol, 1,3-dichloro-2-propanol, ethylenecyanohydrin, 2-nitroethanol, 2-nitro-1-butanol, 2-amino-1-butanol, 3-pyridinemethanol, 2-(ethylamino)ethanol, 2-(dimethylamino)-ethanol, 3-(dimethylamino)-1-propanol, 1-(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, ethylbutyrate, propylpropionate, ethylvalerate, n-butylpropionate, n-propylbutyrate, isobutylpropionate, isopropylbutyrate, diacetoxydimethylsilane, (3-chloropropyl)trimethoxy-silane, triethoxysilane, methylhydrazine, pyridazine, 2-methylpyridine1-oxide, 1-piperidinecarboxaldehyde, (chloromethyl)-oxirane, dimethylcarbamoylchloride, 4-pyridinecarboxaldehyde, 2-nitropropane, 1-acetylpiperidine, 1-nitropropane, 4-methoxybenzaldehyde, 1,1'-oxybis-2-ethoxy-ethane, trimethylphosphite, tetrahydrofurfurylalcohol, 4-(2-hydroxyethyl)morpholine, 1,3-butanediol, 1,2-ethanedioldinitrate, 3-oxiranyl-7-oxabicyclo[4,1,0]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-1-ol, 2-ethylbutyraldehyde, 2-fluorobenzaldehyde, 1,6-heptadiyne, 2-nitrotoluene, methyl-2-chloroacrylate, 2-furancarbonylchloride, salicylicaldehyde, 4,5-dihydro-2-methylthiazole, 1,4-difluoro-2-nitrobenzene, benzisoxazole, thiazole, m-fluoroaniline, 1,4-dichloro-2-butyne, aniline, p-fluoroaniline, 1-methyl-1h-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 extracting 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-1,3-dioxane, beta-propiolactone, gamma-butyrolactone, dimethylmalonate, ethyl acetoacetate, 1,2-ethanedioldiacetate, cyanoacetic acid methyl ester, 2-propenyl ester of 3-oxobutanoic acid, pentanedioic acid dimethyl ester, ethyloxalate, methyl ethyl ester of 3-oxobutanoic acid, ethylene glycol monomethylether acetate, dimethylmaleate, ethyl ester of cyanoacetic acid, ethyl methyl ester of butanedioic acid, diethylmalonate, methyl acid of 2-hydroxypropanoic acid, t-butylacetoacetate, ethylsuccinate, ethyl ester of chloroacetic acid, allylidene diacetate, diethyl ester of adipic acid, ethyl phenylacetate, phenyl methyl ester of acetic acid, dibutyl ester of (z)-2-butenedioic acid, 2-methylpropyl ester of acetic acid, 2-propenyl ester of butanoic acid, methyl benzoate, tetramethyl ester of acid silicic acid, 2-propenoic acid butyl ester, 2-methylpropyl propenoic acid ester, formic acid pentyl ester, cyclohexyl acetic acid ester, 3-methylbutanoic acid ethyl ester, ethyl benzoate, 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, 1-hydroxy-2-propanone, acetonylacetone, acetylacetone, 2-oxepanone, chloroacetone, n-methyl-2-pyrrolidinone, 5-ethyldihydro-2(3h)-furanone, 1-bromo-2-propanone, 5-methyl-2(3h)-furanone, 2-cyclohexen-1-one, 1-(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, 1-(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-1-phenyl-1-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, 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-1-butanol, 1-methoxy2-propanol, ethoxyethanol, 2-furanmethanol, tetrahydro-2h-pyran-2-methanol, 3-methoxyphenol, 1-propoxy-2-propanol, 2,2'-oxybis(2,1-ethanediyloxy)bisethanol, 2,2'-(methylimino)bis-ethanol, 2 -(2-methoxyethoxy)ethanol, glycol, triethyleneglycol, diethyleneglycol, 1,3-propanediol, propyleneglycol, tripropylene glycol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethoxyethylacrylate, ethylbutyrate, propylpropionate, ethylvalerate, n-butylpropionate, n-propylbutyrate, isobutylpropionate, isopropylbutyrate, 1,1'-oxybis-2-ethoxy-ethane, trimethylphosphite, tetrahydrofurfurylalcohol, 4 -(2-hydroxyethyl)morpholine, 1,3-butanediol, 1,2-ethanedioldinitrate, 3-oxiranyl-7-oxabicyclo[4,1,0]heptane, dibutyloxalate, morpholine, ((1,1-dimethylethoxy)methyl)oxirane, dimethoxytetrahydrofuran, triethylorthoformate, citral, allylacrylate, butyllactate, nitrocyclohexane, 2-propen-1-ol, methacrylalcohol, 2,6-dimethylmorpholine, 2-butanoneoxime.

Preferably, said organic extracting 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-1,3-dioxane, beta-propiolactone, gamma-butyrolactone, dimethylmalonate, ethyl acetoacetate, 1,2-ethanedioldiacetate, cyanoacetic acid methyl ester, 2-propenyl ester of 3-oxobutanoic acid, pentanedioic acid dimethyl ester, ethyloxalate, methyl ethyl ester of 3-oxobutanoic acid, ethylene glycol monomethylether acetate, dimethylmaleate, ethyl ester of cyanoacetic acid, ethyl methyl ester of butanedioic acid, diethylmalonate, methyl acid of 2-hydroxypropanoic acid, t-butylacetoacetate, ethylsuccinate, allylidene diacetate, diethyl ester of adipic acid, ethyl phenylacetate, phenyl methyl ester of acetic acid, dibutyl ester of (z)-2-butenedioic acid, 2-methylpropyl ester of acetic acid, tetramethyl ester of silicic acid, butyl ester of 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, methyl hexanoate, diglyme, crotyl glycol ether, diethylene glycol monobutylether, diethylene glycol dibutylether, isoamylformate, 2,5,8,11-tetraoxadodecane, 1-hydroxy-2-propanone, acetonylacetone, acetylacetone, 2-oxepanone, n-methyl-2-pyrrolidinone, 5-ethyldihydro-2(3h)-furanone, 5-methyl-2(3h)-furanone, 2-cyclohexen-1-one, 1-(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-1-phenyl-1-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-1-butanol, 1-methoxy2-propanol, ethoxyethanol, 2-furanmethanol, tetrahydro-2h-pyran-2-methanol, 3-methoxyphenol, 1-propoxy-2-propanol, 2,2'-oxybis(2,1-ethanediyloxy)bisethanol, 2-(2-methoxyethoxy)ethanol, glycol, triethyleneglycol, diethyleneglycol, 1,3-propanediol, propyleneglycol, tripropyleneglycol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 2-ethoxyethylacrylate, ethylbutyrate, propylpropionate, ethylvalerate, n-butylpropionate, n-propylbutyrate, isobutylpropionate, isopropylbutyrate, 1,1'-oxybis-2-ethoxy-ethane, tetrahydrofurfurylalcohol, 4-(2-hydroxyethyl)morpholine, 1,3-butanediol, 1,2-ethanedioldinitrate, 3-oxiranyl-7-oxabicyclo[4,1,0]heptane, dibutyloxalate, ((1,1-dimethylethoxy)methyl)oxirane, dimethoxytetrahydrofuran, triethylorthoformate, citral, allylacrylate, butyllactate, 2-propen-1-ol, methacrylalcohol, 2-butanoneoxime.

More preferably, said organic extraction agent is selected from the group consisting of beta-propiolactone, gamma-butyrolactone, 1-hydroxy-2-propanone, acetonylacetone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1,2-ethanedioldiacetate, glycol, ethyloxalat, 3-oxobutanoicacid-1-methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, triethyleneglycol, diethylmalonate, furfural, diethylene glycol, 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-1-butanol, 4-methyl-3-penten-2-one, 1-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 ethylbenzoate.

In particular, said organic extracting agent 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 from 1 to 10 bara, preferably from 1 to 7 bara.

According to a preferred embodiment, said organic extraction agent has a melting point below 0°C, advantageously below -5°C, preferably below -10°C, in particular below -20°C.

According to a preferred embodiment, when step b) is carried out at a pressure of 3 to 6 bara, said organic extraction agent 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 extraction agent 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 extraction agent has a melting point below -10°C, preferably -20°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, 1-hydroxy-2-propanone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1,2-ethanedioldiacetate, glycol, ethyloxalate, 3-oxobutanoicacid-1-methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, diethylmalonate, furfural, diethyleneglycol, t-butylacetoacetate, ethylsuccinate, 1,3-propanediol, cyclopentanone, propyleneglycol, 1-cyclopropylethanone, 2-methoxyethanol, 2,3-pentanedione, tripropyleneglycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3-methoxy-1-butanol, 4-methyl-3-penten-2-one, 1-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-1-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-1-butanol, 4-methyl-3-penten-2-one, 1-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-1-butanol, 4-methyl-3-penten-2-one, 1-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.

Process for the production of trifluoroethylene

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

Said method comprises 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 B 1 comprising trifluoroethylene and a stream B 2 comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane,

C') implementation of the purification method 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. The implementation of the processes according to the invention in the presence of hydrogen and/or anhydrous chlorotrifluoroethylene makes it possible to effectively increase the lifetime 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 aluminum-based. In particular, the support is alumina. The alumina may be alpha alumina. Preferably, the alumina comprises at least 90% alpha alumina. It has been observed that the conversion of the hydrogenolysis reaction is improved when the alumina is an alpha alumina. Thus, the catalyst is more particularly palladium supported on alumina, advantageously palladium supported on an alumina comprising at least 90% alpha alumina, preferably palladium supported on an alpha alumina.

Preferably, the 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 an 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 selected from the group consisting of hydrogen, carbon monoxide, nitrogen monoxide, formaldehyde, C ₁ -C ₆ alkanes and C ₁ -C ₁₀ hydrohalocarbons, or a mixture thereof; preferably hydrogen or a C ₁ -C ₁₀ 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; nitrogen is preferred.

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 T1 to a temperature T2. In particular, the temperature of the catalytic bed is increased from a temperature T1 to a temperature T2 higher than T1 with a temperature gradient of less than 0.5°C/min. The temperature gradient implemented makes it possible to avoid early degradation of the catalyst and thus to allow a better yield or a better productivity of the hydrogenolysis reaction. In particular, the temperature is increased with a temperature gradient of 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 T1 represents the initial temperature of the activation step. This temperature T1 may be room temperature. Alternatively, the temperature T1 may 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 particular 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 20 h, in particular from 15 min to 15 h, more particularly from 30 min to 10 h, preferably from 1 h to 10 h.

Preferably, the gas stream used during the activation step does not comprise oxygen. Preferably, the activation step can be carried out with an amount 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 an amount 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 T1 to a temperature T2 in stages. Activating the catalyst in stages makes it possible to make the catalyst more efficient. The implementation of stages makes it possible to avoid degradation of the catalyst. It has also been observed that the properties of the catalyst are further improved if the temperature rise between the stages is gradual and relatively slow compared to the usual conditions for activating a catalyst. Thus, preferably, in the activation step, between two stages, the temperature is increased with a temperature gradient of less than 0.5°C/min. The temperature gradient implemented between two stages makes it possible to avoid early degradation of the catalyst and thus to allow a better yield or better productivity of the hydrogenolysis reaction. In particular, the temperature is increased with a temperature gradient of 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 T1 represents the initial temperature of the activation step. This temperature T1 may be room temperature. Alternatively, the temperature T1 may 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 particular 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 20 h, in particular from 15 min to 15 h, more particularly from 30 min to 10 h, preferably from 1 h to 10 h. The catalyst activation step i') contains at least one stage between the temperature T1 and the temperature T2. The catalyst activation step i') can comprise several stages between the temperature T1 and the temperature T2. Preferably, the activation step comprises at least one stage at a temperature T1a of between 90 and 120°C. The presence of a step between 90°C and 120°C is preferred to increase the lifetime of the catalyst. The activation step may also comprise one or more steps between the temperature T1 and T1a and/or between the temperature T1a and T2. Preferably, each step between the temperature T1 and the temperature T2 may 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 step between the temperature T1 and the temperature T2 may last between 5 min and 24 h, preferably between 10 min and 20 h, in particular between 15 min and 15 h, more particularly between 30 min and 10 h. In particular, the temperature hold T1a may 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 temperature hold T1a may last between 5 min and 24 h, preferably between 10 min and 20 h, in particular between 15 min and 15 h, more particularly between 30 min and 10 h.

The gas stream used during the activation step may be different over time. For example, the gas stream may comprise an inert gas between two stages and for example comprise a reducing agent between two other stages. In particular, the gas stream comprises an inert gas when the activation step is implemented between temperature T1 and T1a and the gas stream comprises a reducing agent, preferably hydrogen or C ₁ -C ₁₀ hydrohalocarbons as defined above, when the activation step is implemented between temperature T1a and T2. Thus, the gas stream used during the activation step is modified during the stage implemented at temperature T1a. Alternatively, the gas stream may comprise a reducing agent such as hydrogen or C ₁ -C ₁₀ hydrohalocarbons as defined above throughout the activation step, optionally in admixture with an inert gas such as nitrogen. It has been observed that the use of a reducing agent such as hydrogen or C ₁ -C ₁₀ hydrohalocarbons as defined above, optionally in admixture with an inert gas such as nitrogen, during the temperature rise between the temperature T1a of said step and the temperature T2 represents an additional advantage in terms of productivity. As mentioned above, the temperature T2 is maintained for a certain duration. During this step at the temperature T2, the gas stream may be modified. Thus, the gas stream during the step at the temperature T2 may comprise hydrogen or a C ₁ -C ₁₀ 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 may be carried out with an amount 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 may be carried out with an amount 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 contacting said catalyst with a gas stream that comprises chlorotrifluoroethylene, and optionally hydrogen. It has been noted that chlorotrifluoroethylene (CTFE) allows the catalyst to be activated, in particular when hydrogen is also present. This allows an improvement in the trifluoroethylene production process. Activation in the presence of CTFE allows the catalyst to be activated at a lower temperature and therefore provides a less energy-consuming process. 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' below 100°C. This temperature T2' can be reached from a temperature T1' using a low temperature gradient. Thus, during the activation step, the temperature of the catalytic bed is increased from a temperature T1’ to a temperature T2’ higher than T1’, preferably the temperature of the catalytic bed is increased from a temperature T1’ to a temperature T2’ higher than T1’ with a temperature gradient of less than 0.5°C/min. The temperature gradient implemented makes it possible to avoid early degradation of the catalyst and thus to allow a better yield or a better productivity of the hydrogenolysis reaction. In particular, the temperature is increased with a temperature gradient of 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 reactor inlet. 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 T1' may 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 carried out 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 catalytic bed temperature of 90°C to 150°C. In particular, the implementation of 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. The regeneration step can be carried out periodically depending on the productivity or the conversion obtained in step a). 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 particular 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 may be carried out at a temperature between 300°C and 450°C, preferably between 300°C and 400°C. The regenerated catalyst may be reused in step A’) of the present process.

Hydrogenolysis reaction

The process comprises, as mentioned above, a step of hydrogenolysis reaction 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 in 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 fixed catalytic bed temperature 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 carried out at a fixed catalytic bed temperature 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 carried out at a fixed catalytic bed temperature 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 and 160°C.

The H ₂ /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/H ₂ 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 of 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, in particular between 10 and 30 seconds, more particularly between 15 and 25 seconds.

Examples

Method of selecting organic extracting agent

The selection of the organic extractant 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:

S _1,2 = (γ _1,S )/(γ _2,S ) in which

γ _1,S represents the activity coefficient of the first compound 1 in the organic extraction agent considered at infinite dilution,

γ _2,S represents the activity coefficient of the second compound 2 of the binary pair 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 pair (1,2) considered. The absorption capacity is calculated by the formula C _2,S = 1/(γ _{2 , S} ) in which γ _{2 , S} represents the activity coefficient of the second compound of the binary pair considered in said organic extraction agent studied at infinite dilution.

The calculations are repeated for each organic extractant studied. Minimum values of separation factor and absorption capacity 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 extractants having a separation factor S _1,2 greater than 2 are suitable for separating a mixture comprising chlorotrifluoroethylene (CTFE) and 1,1,2-trifluoroethane.

[Table 1]

Table 1 – Capacity and Separation Factor of Organic Extracting Agent Organic extracting agent Separation factor S _1.2 Absorption capacity C _2,S beta-propiolactone 18,637 1,020 gamma-butyrolactone 18,152 1,518 1-hydroxy-2-propanone 16,833 1,153 acetonylacetone 14,051 1,654 trimethylphosphate 13,656 1,794 acetylacetone 11,908 1,377 Propylene carbonate 11,813 0.907 dimethylmalonate 11,810 1,275 ethylacetoacetate 11,780 1,465 1,2-ethanediol acetate 11,219 1,386 glycol 10,029 0.254 ethyloxalate 8,921 1,787 3-oxobutanoicacid-1-methylethylester 8,491 1,502 Ethylene glycol monomethyl ether acetate 8,447 1,590 dimethylmaleate 8,125 1,173 triethylphosphate 7,383 2,165 Triethylene glycol 7,378 0.797 diethylmalonate 7,191 1,552 furfural 6,755 0.934 diethylene glycol 6,581 0.587 t-butylacetoacetate 6,235 1,412 ethyl succinate 6,062 1,453 1,3-propanediol 5,844 0.520 cyclopentanone 5,576 1,593 Propylene glycol 5,499 0.390 1-cyclopropylethanone 5,047 1,372 2-methoxyethanol 4,605 0.746 2,3-pentanedione 4,572 1,138 tripropylene glycol 4,251 1,407 cyclohexanone 4,105 1,349 diethylcarbonate 4,057 1,282 1,3-butanediol 3,890 0.524 3-methoxy-1-butanol 3,621 1,298 4-methyl-3-penten-2-one 3,603 1,219 1-methoxy2-propanol 3,495 0.964 phenylacetate 3,406 0.959 cycloheptanone 3,360 1,296 3-methylcyclohexanone 3,330 1,326 4-methylcyclohexanone 3,284 1,302 2,3-hexanedione 3,191 1,060 3,4-hexanedione 3,173 1,028 citral 3,115 1,239 1,5-pentanediol 3,006 0.289 Diethylene glycol monobutyl ether 2,989 1,027 4-phenyl-2-butanone 2,974 0.955 ethanol 2,874 0.383 n-butyl acetate 2,838 1,275 4-methyl-2-pentanone 2,760 1,091 3-hexanone 2,699 1,122 4,4-dimethyl-2-pentanone 2,623 1,179 5-methyl-2-hexanone 2,541 1,057 2,2-dimethylcyclohexanone 2,512 1,124 ethylbenzoate 2,148 0.829

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 extraction agent is continuously introduced 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 (11)

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 extraction agent to form

1. a second composition comprising said organic extractant and 1,1,2-trifluoroethane; and
2. a first stream comprising chlorotrifluoroethylene,

b) Recovery and separation of said second composition to form a second stream comprising said organic extraction agent and a third stream comprising 1,1,2-trifluoroethane, preferably said second stream is recycled to step a). Process according to the preceding claim, characterized in that said organic extraction agent has a flash point greater than 13°C. Process 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. Process 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 . Process according to any one of the preceding claims, characterized in that said organic extraction agent has a separation factor S _1,2 greater than or equal to 2.0, said separation factor being calculated by the formula S _1,2 = (γ _1,S )/(γ _2,S ) in which
γ _1,S represents the activity coefficient of chlorotrifluoroethylene in said organic extractant at infinite dilution,
γ _2,S represents the activity coefficient of 1,1,2-trifluoroethane in said organic extractant at infinite dilution,
advantageously the separation factor S _1.2 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. Process according to any one of the preceding claims, characterized in that 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 C _{2 , S} = 1/(γ _{2 , S} ) in which γ _{2 , S} represents the activity coefficient of 1,1,2-trifluoroethane in said organic extraction agent at infinite dilution. Process 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. Process according to any one of the preceding claims, characterized in that said organic extraction agent has a melting point below 0°C. Method according to any one of the preceding claims, characterized in that step b) is carried out at a pressure of from 1 to 10 bara, preferably from 1 to 7 bara. A process according to any one of the preceding claims, characterized in that said organic extracting agent is selected from the group consisting of H ₂ O, beta-propiolactone, gamma-butyrolactone, 1-hydroxy-2-propanone, acetonylacetone, trimethylphosphate, acetylacetone, propylenecarbonate, dimethylmalonate, ethylacetoacetate, 1,2-ethanedioldiacetate, glycol, ethyloxalat, 3-oxobutanoicacid-1-methylethylester, ethyleneglycolmonomethyletheracetate, dimethylmaleate, triethylphosphate, triethyleneglycol, diethylmalonate, furfural, diethyleneglycol, t-butylacetoacetate, ethylsuccinate, 1,3-propanediol, cyclopentanone, propyleneglycol, 1-cyclopropylethanone, 2-methoxyethanol, 2,3-pentanedione, tripropyleneglycol, cyclohexanone, diethylcarbonate, 1,3-butanediol, 3-methoxy-1-butanol, 4-methyl-3-penten-2-one, 1-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. Process for producing trifluoroethylene in a reactor equipped 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 B 1 comprising trifluoroethylene and a stream B 2 comprising chlorotrifluoroethylene and 1,1,2-trifluoroethane,
C') implementation of the purification method according to any one of the preceding claims 1 to 10 from said stream B2 .