Technical Field of the Invention
The invention relates to a process for purifying 2,3,3,3-tetrafluoro-l-propene. In addition, the invention also relates to a process for production and purification of 2,3,3,3-tetrafluoro-l-propene.
BACKGROUND OF THE INVENTION
Hydrofluorocarbons (HFCs) and particularly hydrofluoroolefins (HFOs), such as 2,3,3,3-tetrafluoro-the l-propene (HFO-1234yf) are compounds known for their cooling properties and heat transfer fluids, fire extinguishing, propellants, foaming agents, blowing agents, gaseous dielectrics, polymerization medium or monomer, fluid media, abrasives agents, drying agents and fluids for energy production unit. The HFO have been identified as desirable alternatives to HCFCs due to their low values ​​ODP (Ozone Depletion Potential and potential to deplete the ozone layer) and GWP (Global Warming Potential or GWP).
Most manufacturing processes hydrofluoroolefins use a fluorination reaction and / or dehydrohalogenation. These reactions are carried out in gas phase and generate impurities that must be therefore removed to obtain the desired compound in sufficient purity for the intended applications.
For example, in the context of the production of 2,3,3,3-tetrafluoro-l-propene (HFO-1234yf), the presence of impurities such as l-chloro-3,3,3-trifluoro-l propene (1233zd), 1,3,3,3-tetrafluoro-l-propene (1234ze), and 1,1,1,3,3-pentafluoropropane (245fa) are observed. These impurities are isomers of the major components to be obtained by the method for producing 2,3,3,3-tetrafluoro-l-propene addition thereto, ie 2-chloro-3,3,3-trifluoro-l- propene (1233xf) and 1,1,1,2,2-pentafluoropropane (245cb). Given the respective boiling points of l-chloro-3,3,3-trifluoro-l-propene (1233zd), 1,3,3,3-tetrafluoro-l-propene (1234ze) and 1,1, 1,3,3-pentafluoropropane (245fa), they can accumulate in the reactor and thus prevent the formation of products of interest.
Purification of this type of reaction may be effected by various techniques known to the prior art, such as e.g. distillation. However, when the compounds to be purified have boiling points too close or when they form azeotropes or azeotrope-like compositions, distillation is not an efficient process. extractive distillation methods have been described.

Is known from EP 0864554 a method for purifying a mixture comprising 1,1,1,3,3-pentafluoropropane (245fa) and l-chloro-3,3,3-trifluoro-trans-l-propene (1233zd ) by distillation in the presence of a solvent having a higher boiling point than 1-chloro-3,3,3-trifluoro-trans-l-propene.
by WO 03/068716 discloses a method of recovering pentafluoroethane from a mixture comprising pentafluoroethane and chloropentafluoroethane by distillation in the presence of hexafluoropropene.
is also known from WO 98/19982 a method for purifying 1,1-difluoroethane by extractive distillation. The method comprises contacting an extraction agent with a mixture of 1,1-difluoroethane and vinyl chloride. The extraction agent selected from hydrocarbons, alcohols, chlorocarbons having a boiling point between 10 ° C and 120 ° C.
As mentioned in WO 98/19982, the selection of the extracting agent can be complex depending on the products to be separated. There is therefore still a need for the implementation of a particular method for purifying 2,3,3,3-tetrafluoro-l-propene.
Summary of the Invention
In a method for producing 2,3,3,3-tetrafluoro-l-propene, the choice of specific operational conditions may favor the presence of certain impurities or isomers thereof. The presence of impurities such as 1,3,3,3-tetrafluoro-l-propene (1234ze) may be seen as that of l-chloro-3,3,3-trifluoro-l-propene (1233zd), and 1,1,1,3,3-pentafluoropropane (245fa). These impurities can originate from side reactions induced by compounds produced as an intermediate during the production of 2,3,3,3-tetrafluoro-l-propene, and may have physical properties such as their removal may be complex. The present invention enables the production of 2,3,3,3-tetrafluoro-l-propene with improved purity.

According to a first aspect, the present invention provides a process for purifying 2,3,3,3-tetrafluoro-l-propene (1234yf) from a first composition comprising 2,3,3,3-tetrafluoro-l propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of methyl chloride ( 40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), said method comprising the steps of:

a) contacting said first composition with at least one organic extractant to form a second composition; b) extractive distillation of said second composition to form:

i) a third composition comprising said organic extractant, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E) and optionally or not at least a compound selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-2,3,3, 3-pentafluoropropene (1225ye-E); and

ii) a stream comprising 2,3,3,3-tetrafluoro-l-propene, c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising 3,3,3 trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of chloromethane (40), 1,1- difluoroethane ( 152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-l, 2,3,3,3-pentafluoropropene (1225ye-E); preferably the stream comprising said organic extractant is recycled to step a).

Preferably, the stream comprising 2,3,3,3-tetrafluoro-l-propene formed in step b) is recovered. This current can possibly be purified to a purity suitable for specific business requirements.

According to a preferred embodiment, said organic extractant is a solvent selected from the group consisting of hydrocarbon, hydrohalocarbure, alcohol, ketone, amine, ester, ether, aldehyde, nitrile, carbonate, thioalkyl, amide and heterocycle; or said organic extractant is difluoroéthylsilane, triethylfluorosilane or perfluorobutanoic acid; preferably said organic extractant is a solvent selected from the group consisting of ketone, ester, aldehyde, ether, carbonate, and heterocycle.

According to a preferred embodiment, said organic extractant has a boiling point between 10 and 150 ° C.

According to a preferred embodiment, said organic extractant may have a separation factor If two greater than or equal to 1.1, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein

yi, s represents the coefficient of activity of 2,3,3,3-tetrafluoro-l-propene in said organic extractant at infinite dilution,

IP is the saturation vapor pressure of 2,3,3,3-tetrafluoro-l-propene,

Y2, s represents the coefficient of activity of the 3,3,3-trifluoropropene (1243zf) or trans 1,3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant in infinite dilution;

P2 represents the saturation vapor pressure of 3,3,3-trifluoropropene (1243zf) or trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E);

preferably, the separation factor is greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, greater than or equal 2.0.

According to a preferred embodiment, said organic extractant has an absorption capacity C2, s greater than or equal to 0.20, said absorptive capacity is calculated by the formula C2, s = l / (y2, s ) wherein y2, s represents the coefficient of activity of the 3,3,3-trifluoropropene (1243zf) or trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said agent organic extraction at infinite dilution; advantageously C2 absorption capacity, s is greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0.

According to a preferred embodiment, said organic extractant may have a separation factor If two greater than or equal to 1.1, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein yi, s represents the coefficient of activity of 2,3,3,3-tetrafluoro-l-propene in said organic extractant at infinite dilution, PI represents the vapor pressure saturating 2,3,3,3-tetrafluoro-l-propene, y2, s is the activity coefficient of the 3,3,3-trifluoropropene (1243zf) in said organic extractant at infinite dilution and P2 represents the saturation vapor pressure of 3,3,3-trifluoropropene (1243zf); and said organic extractant may have a separation factor If two greater than or equal to 1.1, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein yi, s represents the coefficient of activity of 2,3,3,3-tetrafluoro-l-propene in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 2.3, 3,3-tetrafluoro-l-propene, y2, s is the activity coefficient of trans-1,3,3,3

tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution and P2 represents the saturation vapor pressure of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E); advantageously, said organic extractant has a higher separation factor than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8 , greater than or equal to 2.0.

According to a preferred embodiment, said organic extractant can have an absorbent capacity C2, s greater than or equal to 0.20, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s is the activity coefficient of the 3,3,3-trifluoropropene (1243zf) in said organic extractant at infinite dilution; and said organic extractant can have an absorbent capacity C2, s greater than or equal to 0.20, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s represents the coefficient of activity of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution; advantageously C2 absorption capacity, s is greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0.

According to a preferred embodiment, said first composition is an azeotropic composition or quasi-azeotropic comprising 2,3,3,3-tetrafluoro-l-propene, trans-1,3,3,3-tetrafluoro-l-propene (1234ze -E), 3,3,3-trifluoropropene (1243zf) and optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1, 1,1,2-tetrafluoroethane (134a), trans-1,2,3,3,3-pentafluoropropene (1225ye-E).

According to a preferred embodiment, said organic extractant is selected from the group consisting of said organic extractant is selected from the group consisting of 2-methoxy-l-propene j l, 2-epoxypropane j ethoxy-ethene , dimethoxymethane, methyl acetate, isobutanal, isopropylformate, ethylacetate, butanone, n-propylformate, 1,2-dimethoxyethane, isopropyl acetate, 2-methylbutanal, ethylpropionate, 1,2-dimethoxypropane, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1 , 3-dioxane, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, diethyl carbonate, n-butylacetate, 2-hexanone, 5-hexen-2-one, l-ethoxy-2-propanol, hexanal , 2- (dimethylamino) -ethanol, 2-methylpyrazine, 1-methylpiperazine, valeronitrile, 4-methyl-2-hexanone, l-methoxy-2-acetoxypropane, 2,6-dimethylmorpholine, methylhexanoate, l-propoxy-2-propanol ; preferably said organic extractant is selected from the group consisting of ethoxy-ethene, dimethoxymethane, methyl acetate, isobutanal, isopropylformate, ethylacetate, butanone, 1,2-

dimethoxyethane, isopropyl acetate, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3-dioxane, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, diethyl carbonate, n-butyl acetate, l-ethoxy 2-propanol, hexanal; preferably said organic extractant is selected from the group consisting of dimethoxymethane, butanone, isopropyl acetate, dioxane, trimethoxymethane, 1,3-dioxane, n-butyl acetate, l-ethoxy-2-propanol, hexanal; in particular said organic extractant is selected from the group consisting of dimethoxymethane, isopropylacetate, dioxane, trimethoxymethane, 1,3-dioxane, n-butyl acetate, l-ethoxy-2-propanol, hexanal.

According to a preferred embodiment, the stream comprising 2,3,3,3-tetrafluoro-l-propene formed in step b) is recovered and is free of trans-l, 3,3,3-tetrafluoro-l -propene (1234ze-E) and / or 3,3,3-trifluoropropene (1243zf) and / or at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a) , chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-1,2,3,3,3-pentafluoropropene (1225ye-E).

According to a preferred embodiment, said first composition comprises impurities having a boiling point below the boiling point of 2,3,3,3-tetrafluoro-l-propene and optionally heavy impurities, and the method comprises previously in step a) the steps of:

i ') implementation or providing a composition comprising 2,3,3,3-tetrafluoro-l-propene, impurities having a lower boiling point than the boiling point of 2,3,3,3 tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye - E), and optionally the heavy impurities;

ii ') distillation of said composition of step i) to remove the top of column impurities having a boiling point below the boiling point of 2,3,3,3-tetrafluoro-l-propene and form a first stream comprising 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-1-propene (1234ze-E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane

(134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), and optionally the heavy impurities; recovered at the bottom of distillation column;

iii ') optionally, distilling said first stream recovered at the bottom of distillation column in step ii') to retrieve the column head a second stream comprising 2,3,3,3-tetrafluoro-l-propene, 3, 3,3-trifluoropropene

(1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye- E), and at the bottom of distillation column a stream comprising the heavy impurities;

said first stream recovered in step ii ') or said second stream recovered in step iii') corresponding to said first composition implemented in step a).

The heavy impurities may contain eg 1,1,1,3,3,3-hexafluoropropane

(236fa), 1,1,1,2,3,3-hexafluoropropane (236ea), 1,1,1,2,3,3,3-heptafluoropropane (227ca), cis-1,3,3,3 tetrafluoro-l-propene (Z-1234ze), dimers or trimers from one of the compounds present in the composition or the current considered, for example hydrocarbons such as C4 or C5 hexafluorobutene (1336), heptafluorobutène (1327 ), octafluorobutane (338), nonafluoropentène (1429), heptafluoropentène (1447).

According to a second aspect of the present invention, a process for producing 2,3,3,3-tetrafluoro-l-propene is provided. Said method comprises the steps of:

A) fluorination in the presence of a catalyst a compound of the formula CX (Y) 2-CX (Y) m - CHmXY (I) wherein X and Y are independently H, F, or Cl and m = 0 or 1 ; and / or fluorination in the presence of a catalyst of a compound of formula (CX n Y 3-n) CH p Xi- pCH m X 2 m (II) wherein X is independently of each other Cl, F, I or Br; Y is independently of each other H, Cl, F, I or Br; n is 1, 2 or 3; and m is 0, 1 or 2; and p is 0 or 1;

B) recovering a stream comprising 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene ( 1234ze-E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane

(115), 1,1,1,2-tetrafluoroethane (134a), trans-l,2,3,3,3-pentafluoropropene (1225ye- E), ;

C) implementing the method according to any one of claims 1 to 9 from the stream recovered in step B).

According to another aspect, the present invention provides a composition comprising 2,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene ( 1234ze-E) and an organic extractant having:

a separation factor If two greater than or equal to 1.40, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein yi, s represents the activity coefficient of 2,3,3,3-tetrafluoropropene in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 2,3,3,3-tetrafluoropropene, y2, s represents the coefficient of activity of the 3,3,3-trifluoropropene (1243zf) in said organic extractant at infinite dilution, P2 represents the saturation vapor pressure of 3,3,3-trifluoropropene (1243zf) and a separation factor Si, 2 greater than or equal to 1.40, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein yi, s represents the coefficient of activity of the 2, 3,3,3-tetrafluoropropene in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 2,3,3,3-tetrafluoropropene, y2, s represents the coe FFICIENT Attraction trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution, P2 represents the saturation vapor pressure of the trans-3, 3,3-tetrafluoro-l-propene (1234ze-E);

preferably said organic extractant has:

an absorption capacity C2, s greater than 0.60, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s represents the coefficient of activity of 3.3 , 3-trifluoropropene (1243zf) in said organic extractant at infinite dilution; and a capacitor C2 absorption, s greater than 0.60, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s is the activity coefficient of the trans- l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution.

De préférence, l'agent d'extraction organique est sélectionné parmi le groupe consistant en acétaldehyde, methylformate, 2-methoxy-l-propene, 1,2-epoxypropane, ethoxy-ethene, dimethoxymethane, l-chloro-l,2,2-trifluoropropane, 3-chloro-l,l,l-trifluoropropane, ethanedial, 2-chloro-l,l,l,3-tetrafluoropropane, propanone, methylacetate, 4-methoxy-2-methyl-2-butanethiol, difluorodiethylsilane, isobutanal, isopropylformate, methylglyoxal, 2,3-dichloro-l,l,l-trifluoropropane, ethylacetate, butanone, n-propylformate, l,3-dichloro-l,l,2-trifluoropropane, l,l-dichloro-2,2,3-trifluoropropane, 1,2-dimethoxyethane, 1,3-dichloro-1,2,2-trifluoropropane, isopropylacetate, diethylsulfide, l,3-dichloro-l,2,3-trifluoropropane, 2-methylbutanal, 2-allyloxyethanol, ethylpropionate, 1,2-dimethoxypropane, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3-dioxane, 3,3-dimethyl-2-butanone, pyridine, n-methylmorpholine, 4-methyl-2-pentanone, butyronitrile, l-methoxy2-propanol, diethylcarbonate, n-butylacetate, 2-hexanone, 5-hexen-2-one, 2-methoxyl-propanol, 1-ethoxy-2-propanol, hexanal, 2-(dimethylamino)-ethanol, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-methylpiperazine, n-ethyl-morpholine, valeronitrile, 4-methyl-2-hexanone, l-methoxy-2-acetoxypropane, 2,6-dimethylmorpholine, methylhexanoate, 2-propoxyethanol, l-propoxy-2-propanol.

BRIEF DESCRIPTION OF FIGURES

Figs la-c show schematically a device implementing a method for purifying the 2-3,3,3-tetrafluoro-l-propene according to a particular embodiment of the present invention.

2 schematically shows a device implementing a method for producing 2,3,3,3-tetrafluoro-l-propene according to a particular embodiment of the present invention.

Detailed Description of the Invention

The term "hydrocarbon" as used herein refers to linear or branched alkane compounds C1-C20, C3-C20 cycloalkane, alkene, C5-C20, C5-C20 cycloalkene, arene C6-C18. For example, the alkane term refers to compounds of formula C n H 2n + 2 wherein n is between 1 and 20. The term alkane C1-C20 includes, for example pentane, hexane, heptane, octane, nonane, decane or isomers thereof. The term C 5 -C 20 alkene refers to hydrocarbon compounds containing one or more carbon-carbon double bonds and comprising 5 to 20 carbon atoms. The term cycloalkane C3-C20 refers to a saturated hydrocarbon ring having 3 to 20 carbon atoms. The term C6-C18 refers to cyclic and aromatic hydrocarbon compounds having 6 to 18 carbon atoms. Cycloalkene the term C5-C20 refers to cyclic hydrocarbon compounds comprising from 5 to 20 carbon atoms and comprising one or more double carbon-carbon bonds.

The term "alkyl" means a monovalent radical derived from an alkane, linear or branched, comprising 1 to 20 carbon atoms. The term "cycloalkyl" means a monovalent radical derived from a cycloalkane having 3 to 20 carbon atoms. The term "aryl" means a monovalent radical derived from an arene having 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" refers to 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 having 3 to 20 carbons. The alkyl substituents C1-C20 alkenyl, C2-C20 alkynyl, C2-C20, C3-C20 cycloalkenyl, C3-C20, C6-C18 may be substituted or not by one or more -OH, halogen, -N is C (0) b , -C (0) NR a R b -CN, -N0 2 , -NR a R b , -OR a , -SR a , -C0 2 R a , -OC ( 0) OR a , -OC (0) R a , -C (0) H, -C (0) R a wherein R a and R b are independently of each other hydrogen, C1-C20 unsubstituted alkenyl, unsubstituted C2-C20 alkynyl unsubstituted C2-C20 cycloalkyl, unsubstituted C3-C20 cycloalkenyl, unsubstituted C3-C20 aryl, C6-C18 unsubstituted. In the substituents -NR a R b , R a and R b may form with the nitrogen atom to which they are attached, a saturated or unsaturated, aromatic or nonaromatic, comprising from 5 to 10 ring members.

The term "hydrohalocarbures" refers to compounds of the formula R a X where R a is selected from C1-C20 alkenyl, C2-C20 alkynyl, C2-C20, C3-C20 cycloalkenyl, C3- C20, C6-C18 and X represents a chlorine, fluorine, bromine or iodine. The alkyl substituents C1-C20 alkenyl, C2-C20 alkynyl, C2-C20, C3-C20 cycloalkenyl, C3-C20, C6-C18 may be substituted or not by one or more -OH, halogen, -NR a C (0) R b , -C (0) NR a R b -CN, -N0 2 , -NR a R b , -OR a , -SR a , -C0 2 R a , -OC (0) OR a , -OC (0) R a , -C (0) H, -C (0) R a wherein R a and R b are as defined above.

The term "alcohol" refers to hydrocarbons or hydrohalocarbures as defined above wherein at least one hydrogen atom is replaced with a hydroxyl group -OH.

The term "ketone" refers to hydrocarbons comprising at least one or more carbonyl functional groups R c -C (0) -R d wherein R c and R d are independently from each other alkyl, C1- C20 alkenyl, C2-C20 alkynyl, C2-C20, C3-C20 cycloalkenyl, C3-C20, C6-C18 and may be substituted or not by one or more -OH, halogen, -NR a C (0) R b , -C (0) NR a R b -CN, -N0 2 , -NR a R b , -OR a , -SR a , -C0 2 R a , -OC (0) OR a , -OC (0) R a , -C (0) H, -C (0) R a , wherein R a and R b are, R c and R d may be linked together to form with the carbonyl group to which they are attached, a cyclic ketone having 4 to 10 ring members, preferably from 4 to 7 members. The cyclic ketone may also comprise one or more double carbon-carbon bonds. The cyclic ketone may also be unsubstituted or substituted with one or more substituents as defined above.

The term "amino" refers to hydrocarbons comprising at least one or more amine functional groups -NR c R d wherein R c and R d are as defined above, R c and R d may be linked together to form with the nitrogen atom to which they are attached an aromatic or nonaromatic heterocycle containing from 4 to 10 ring members.

The term "esters" refers to compounds of the formula R c -C (0) -0-R d wherein R c and R d are as defined above, R c and R d may be linked together to form with the ester group a ring comprising from 4 to 20 carbon atoms.

The term "ether" refers to compounds of the formula R c -0-R d wherein R c and R d are as defined above, R c and R d may be linked together to form with the atom oxygen which they are attached a heterocycle containing 4 to 20 carbon atoms.

The term "aldehyde" refers to compounds comprising at least one or more functional groups -C (0) -H.

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

The term "carbonate" refers to compounds of the formula R c -0-C (0) -0-R d wherein R c and R d are as defined above.

The term "thioalkyl" refers to compounds of the formula R c SR d wherein R c and R d are as defined above.

The term "amide" refers to compounds of formula c C (0) N ed wherein R c and R d are as defined above, R e is defined as R c ; R c and R d may be linked together to form with the amide group -C (0) N to which they are attached a cyclic amide containing from 4 to 10 ring members, preferably from 4 to 7 members. The cyclic amide can also include one or more double carbon-carbon bonds. The cyclic amide can also be unsubstituted or substituted with one or more substituents as defined above.

The term "heterocycle" refers to a carbocycle containing from 4 to 10 ring members of which at least one of the ring members is a heteroatom selected from the group consisting of O, S, P and N. The heterocyclic ring may comprise one or more carbon double bond atoms or one or more double carbon-heteroatom bond or one or more double hetero atom-hetero atom bond. 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 4 to 6-membered ring including 1, 2 or 3 ring members are heteroatoms selected from O or N. The heterocycle may be unsubstituted or substituted by one or more substituents selected from -OH , halogen, -NR a C (0) R b , -C (0) NR a R b -CN, -N0 2 , -NR a R b , -OR a , -SR a , -C0 2 R a , - OC (0) OR a , -OC (0) R a , -C (0) H, -C (0) R a wherein R a and R b are as defined above.

The term "azeotropic composition" refers to a liquid mixture of two or more compounds that behave as a single substance, and which boils at fixed temperature keeping an identical composition in liquid phase to the gas phase. The term "quasi-azeotropic composition" refers to a liquid mixture of two or more compounds having a constant boiling or which tends not to split when subjected to boiling or evaporation.

The term "organic extractant" refers to a compound having at least one carbon atom.

According to a first aspect, the invention relates to a process for purifying 2,3,3,3-tetrafluoro-l-propene (1234yf). The purification process is performed from a first composition comprising 2,3,3,3-tetrafluoro-l-propene and at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans-2,3 , 3,3-pentafluoropropene (1225ye-E) and 3,3,3-trifluoropropene (1243zf).

The method may comprise the steps of:

a) contacting said first composition with at least one organic extractant to form a second composition; b) extractive distillation of said second composition to form: i) a third composition comprising said organic extractant and at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans-1,2,3,3,3 pentafluoropropene (1225ye-E) and 3,3,3-trifluoropropene (1243zf); and ii) a stream comprising 2,3,3,3-tetrafluoro-l-propene, c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane

(115), 1,1,1,2-tetrafluoroethane (134a), trans-l,3,3,3-tetrafluoro-l-propene (1234ze-E), trans-l,2,3,3,3-pentafluoropropene (1225ye-E) et 3,3,3- trifluoropropene (1243zf).

Preferably, the stream comprising said organic extractant is recycled to step a).

Advantageously, said first composition may comprise 2,3,3,3-tetrafluoro-l-propene and at least two, at least three, at least four, at least five, at least six or all the compounds selected from group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans-1,2,3,3,3-pentafluoropropene (1225ye-E) and 3,3,3-trifluoropropene (1243zf); and said third composition may comprise at least two, at least three, at least four, at least five, at least six or all the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a) , chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans-1,2,3,3, 3-pentafluoropropene (1225ye-E) and 3,3,3-trifluoropropene (1243zf).

Preferably, said first composition may comprise 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), and at least one compound selected from the group consisting of methyl chloride (40) , 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans -1,2,3,3,3-pentafluoropropene (1225ye-E); and thus said third composition may comprise 3,3,3-trifluoropropene (1243zf), and at least one compound selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1 , 1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans-1,2,3,3,3-pentafluoropropene (1225ye-E ).

In particular, said first composition may comprise 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze -E) and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-l, 2,3,3,3-pentafluoropropene (1225ye-E); and said third composition may comprise 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-1,2,3,3,3-pentafluoropropene (1225ye- E).

Thus, said method can comprise the steps of:

a) contacting said first composition with at least one organic extractant to form a second composition; b) extractive distillation of said second composition to form: i) a third composition comprising said organic extractant, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-l, 2,3,3,3-pentafluoropropene (1225ye-E); and

ii) a stream comprising 2,3,3,3-tetrafluoro-l-propene, c) recovering and separating said third composition to a stream comprising said organic extractant and a stream comprising 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and optionally or not at least one compound selected from the group

consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-1,2,3,3,3-pentafluoropropene (1225ye -E).

Said first composition may comprise between 75 and 99.99% by weight of 2,3,3,3-tetrafluoro-l-propene based on the total weight of the first composition, preferably between 80 and 99.9% by weight, preferably between 85 and 99.8% and in particular between 90 and 99.5% by weight of 2,3,3,3-tetrafluoro-l-propene based on the total weight of the first composition.

When it contains, said first composition may comprise between 0 and 2000 ppm by weight of 1,1-difluoroethane (152a) based on the total weight of the first composition, preferably between 0 and 1000 ppm by weight, preferably between 0 and 500 ppm and in particular between 0 and 250 ppm by weight 1,1-difluoroethane (152a) based on the total weight of the first composition.

When it contains, said first composition may comprise between 0.01 and 25% by weight trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) based on the total weight of the first composition , advantageously between 0.1 and 20% by weight, preferably between 0.2 and 15% by weight, in particular between 0.5 and 10% by weight, more particularly between 3 and 10% by weight trans-l, 3,3,3 tetrafluoro-l-propene (1234ze-E) based on the total weight of the first composition.

When it contains, said first composition may comprise less than 2000 ppm by weight of 1,1,1,2-tetrafluoroethane (134a) based on the total weight of the first composition, advantageously between 1 and 1000 ppm by weight, preferably between 1 and 500 ppm and in particular between 1 and 250 ppm by weight of 1,1,1,2-tetrafluoroethane (134a) based on the total weight of the first composition.

When it contains, said first composition may comprise less than 1% by weight of methyl chloride (40) based on the total weight of the first composition, advantageously between 1 and 5000 ppm by weight, preferably between 1 and 2000 ppm and in particular between 10 and 1500 ppm by weight of methyl chloride (40) based on the total weight of the first composition.

When it contains, said first composition may comprise between 0 and 2000 ppm by weight of chloropentafluoroethane (115) based on the total weight of the first composition, advantageously between 1 and 1000 ppm by weight, preferably between 1 and 500 ppm and in particular between 1 and 250 ppm by weight of chloropentafluoroethane (115) based on the total weight of the first composition.

When it contains, said first composition may comprise less than 2000 ppm by weight of cis-l, 2,3,3,3-pentafluoropropene (1225ye) based on the total weight of the first composition, advantageously between 1 and 1000 ppm by weight , preferably between 1 and 500 ppm and in particular between 1 and 250 ppm by weight of cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z) based on the total weight of the first composition.

When it contains, said first composition may comprise less than 1% by weight of 1,1,1-trifluoropropene (1243zf) based on the total weight of the first composition, preferably between 0 and 5000 ppm by weight, preferably between 1 and 2000 ppm and in particular between 1 and 1500 ppm by weight of 1,1,1-trifluoropropene (1243zf) based on the total weight of the first composition.

According to a particular embodiment, said organic extractant is a solvent selected from the group consisting of hydrocarbon, hydrohalocarbure, alcohol, ketone, amine, ester, ether, aldehyde, nitrile, carbonate, thioalkyl, amide and heterocycle; or said organic extractant is difluoroéthylsilane, triethylfluorosilane or perfluorobutanoic acid. Preferably, said organic extractant is a solvent selected from the group consisting of ketone, ester, aldehyde, ether, carbonate, and heterocycle. Preferably, the heterocycle may be a carbon ring comprising 4 to 6-membered ring including 1, 2 or 3 ring members are heteroatoms selected from O or N.

Preferably the hydrocarbons are selected from the group consisting of 2,2-dimethylbutane, 3-methylpentane, hexane, 2,4-dimethylpentane, cyclohexane, cyclohexene, methylcyclohexane, 2,4,4-trimethyl-l-pentene, 2, 2,4-trimethyl-2-pentene, 1-methylcyclohexene, toluene, 2,3-dimethylhexane, octane, ethylcyclohexane, ethyl benzene, 1,4-dimethylbenzene, 1,3-dimethylbenzene, 1,2,3-trimethylcyclohexane, 1 , 2-dimethylbenzene, styrene.

Preferably, the hydrohalocarbures are selected from the group consisting of

Chloroethane, 3-chloro-l,l,l,2,2,3-hexafluoropropane, 2-chloro-l, 1,1,3,3,3-hexafluoropropane, 1,1,1,3,3-pentafluoropropane, bromofluoromethane, l-bromo-1,2-difluoroethylene, l-chloro-l,l,2,3,3,3-hexafluoropropane, 1-chloro-l, 1,2,2-tetrafluoropropane, 1-chloro-l, 1,2,2,3,3-hexafluoropropane, 2-chloro-l, 1,1,2-tetrafluoropropane, 1,1,1,2,3-pentafluoropropane, trichlorofluoromethane, l-chloro-1,1-difluoropropane, l,l,l-trifluoro-2-bromoethane, l,l-dichloro-2,2,2-trifluoroethane, 1-chloro-2,2,3,3,3-pentafluoropropane, l,2-dichloro-l,l,2-trifluoroethane, 1,1-dichloroethylene, 1,1,1,2,3,4, 4,4-octafluorobutane, 2-chloro-2-fluoropropane, l-chloro-2,2-difluoroethane, 2-

chloropropane, bromoethane, dichloromethane, 2-chloro-l,l,l,3,3-pentafluoropropane, 1-chloro-l,2,2-trifluoropropane, iodomethane, 2,2-dichloro-l,l,l,3,3-pentafluoropropane, 3-chloropropene, 3-chloro-l,l,l-trifluoropropane, l,l,l-trichloro-2,2,2-trifluoroethane, 1,2-dichloro-l,2-difluoroethane, l,2-dichloro-l,l,2,3,3-pentafluoropropane, l,l,2-trichloro-l,2,2-trifluoroethane, l,2-dichloro-l,l,3,3,3-pentafluoropropane, l-chloro-1,2,2,3-tetrafluoropropane, l,l-dichloro-l,2,2,3,3-pentafluoropropane, 2-chloro-2-methylpropane, 3-chloro-l,l,l,3-tetrafluoropropane, 2,3-dichloro-l,l,l,2,3-pentafluoropropane, 1,1-dichloro-2,2,3,3,3-pentafluoropropane, 2-chloro-l,l,l,3-tetrafluoropropane, l,3-dichloro-l,l,2,3,3-pentafluoropropane, l,2-dichloro-3,3,3-trifluoropropene, 1,3-dichloro-l, 1,2,2,3-pentafluoropropane, 1,1,1,2,2,3,4,5,5,5-decafluoropentane, 2,2-dichloro-l,l,l,3-tetrafluoropropane, l-chloro-2,2-difluoropropane, 1,1-dichloroethane, 2-bromopropane, 1,2-dichloro-l,2,3,3,4,4-hexafluorocyclobutane, l,l-dichloro-2,2-difluoroethane, 2,2-dichloro-1,1,3,3-tetrafluoropropane, trichloromethane, 2,3-dichloro-l,l,l,2-tetrafluoropropane, 1,1-dichloro-l,2,2,3-tetrafluoropropane, l,3-dichloro-l,l,2,2-tetrafluoropropane, 1,1,1-trichloro-2,2-difluoroethane, l,2-dichloro-l,2,3,3-tetrafluoropropane, chlorobromomethane, 2-chlorobutane, l,3-dichloro-l,l,3,3-tetrafluoropropane, l,3-dichloro-l,2,2,3-tetrafluoropropane, l,2-dichloro-l,l,2,3-tetrafluoropropane, 3-bromopropene, 2,3-dichloro-1,1,1,3-tetrafluoropropane, l,l-dichloro-2-fluoroethane, 1-bromopropane, l,l-difluoro-l,2,2-trichloroethane, l,l,2-trichloro-l,2-difluoroethane, iodoethane, 2-bromo-2-methylpropane, 1,2-dichloro-l-fluoroethane, 1,1,1-trichloroethane, l-chloro-3-fluoropropane, 2,3-dichloro- 1.1.1- trifluoropropane, tetrachloromethane, 1-chlorobutane, l,3-dichloro-l,l,2-trifluoropropane, l,l-dichloro-2,2,3-trifluoropropane, 1,3,3-trichloro-l, 1,2,2-tetrafluoropropane, 2-chloro-2-methyl butane, 1,2-dichloroethane, l,l,l-trichloro-2,2,3,3-tetrafluoropropane, l,l,3-trichloro-l,2,2,3-tetrafluoropropane, l,3-dichloro-l,2,2-trifluoropropane, trichloroethene, 1,1-dichloropropane, l,2-dichloro-2-fluoropropane, 2-iodopropane, dichlorobromomethane, 2-bromobutane, 2,2-difluorotetrachloroethane, 1,1,2,2-tetrachloro-l,2-difluoro-ethane, 1-fluorohexane, l,3-dichloro-l,2,3-trifluoropropane, 2,3-dichloro-l-propene, 1,2-dichloropropane, 3-chloropentane, trichloroacetaldehyde, isoamylchloride, l,l,l-trichloro-2,2,3-trifluoropropane, l-chloro-4-fluorobutane, l-bromo-3-fluoropropane, 1-bromobutane, l,l,2-trichloro-2-fluoroethane, 1-iodopropane, 1,1,3-trichloro- 1.2.2- trifluoropropane, l,l,3-trichloro-2,2,3-trifluoropropane, cis-l,3-dichloropropene, 2,2-dichlorobutane, bromotrichloromethane, l,l,l,2-tetrachloro-2-fluoroethane, l-bromo-2-chloroethane, 2-bromo-2-methylbutane, trans-l,3-dichloropropene, 2-fluorotoluene, 1,1,2- trichloroethane, l,l,l-trichloro-3-fluoropropane, 3,3,3-trichloro-l-propene, l-chloro-3,3-dimethyl butane, l,l,l,2-tetrachloro-3,3,3-trifluoropropane, 2-bromopentane, trichloroacetylchloride, 2,3-dichlorobutane, l,l,3,3-tetrachloro-l,2,2-trifluoropropane, 1,1,1,3-tetrachloro-2,2,3-trifluoropropane, l-bromo-3-methyl butane, l,3-dichloro-trans-2-butene, 1,3-dichloropropane, tetrachloroethene, 1,2-dibromo-l-fluoroethane, 1,2,2-trichloropropane, 1,2-dichlorobutane, l,2,2,3-tetrachloro-3,3-difluoropropane, 2,3-dichloro-2-methylbutane, 1-bromopentane, l,2-dichloro-2-butene, 1-iodobutane, 1,2-dibromoethane, chlorobenzene,

1.1.2- trichloropropane, 1,3-dichlorobutane, pentachlorofluoroethane, 1,2-dibromopropane,

1.2.3- trichloropropene, l-chloro-3-bromopropane, 1,1,3,3-tetrachloro-l-fluoropropane, l,l,2,2,3-pentchloro-3,3-difluoropropane, 1,1,2,2-tetrachloroethane, 1,2-dichloropentane, tribromomethane.

De préférence, les alcools sont sélectionnés parmi le groupe consistant en methanol, 2,2,2-trifluoroethanol, l,l,l-trifluoro-2-propanol, ethanol, pentafluoro-l-propanol, 2-propanol, tert-butanol, 2,2-difluoroethanol, propanol, 2-allyloxyethanol, 2-butanol, 2-methyl-2-butanol, isobutanol, 2,2,3,3-tetraflouro-l-propanol, 2,2-dimethyl-l-propanol, 3-pentanol, 1-butanol, 1-methoxy2-propanol, l-(dimethylamino)-2-propanol, 3-methyl-3-pentanol, l-chloro-2-methyl-2-propanol, 4,4,4-trifluorobutanol, 3-fluoropropanol, 2-chloroethanol, 2-methoxyl-propanol, 1-ethoxy-2-propanol, 4-methyl-2-pentanol, 1,2-octanediol, 2-chloro-l-propanol, 2-(dimethylamino)-ethanol, 3-hexanol, 2-hexanol, 2-ethoxy-l-propanol, 1-pentanol, 3,3,4, 4,5,5,6,6-octafluoro-l-pentanol, 2,3-dimethylbutanol, 2-ethyl-l-butanol, 2-methyl-l-pentanol, 2-propoxyethanol, l-propoxy-2-propanol, 2-aminophenol.

Preferably, the ketones are selected from the group consisting of 1,1,1-trifluoro-2-propanone, propanone, butanone, 3-pentanone, 2-pentanone, 3,3-dimethyl-2-butanone, 4-methyl- 2-pentanone, 2-hexanone, 5-hexen-2-one, 4-methyl-2-hexanone.

De préférence, les aminés sont sélectionnées parmi le groupe consistant en Ethylamine, isopropylamine, ethylmethylamine, 2-amino-2-methylpropane, n-propylamine, isopropylmethylamine, diethylamine, 2-butanamine, n-methylpropylamine, 1-butylamine, diisopropylamine, 3-methyl-2-butanamine, 3-pentylamine, n-methylbutylamine, l-methoxy-2-propanamine, 2-methoxyethanamine, 2-methoxy-lpropanamine, n-pentylamine, n-methylhydroxylamine, dipropylamine, 2-ethoxyethanamine, n-methyl-l,2-ethanediamine, pyridine, 1,2-diaminoethane, 1,2-propanediamine, 2-ethylbutylamine, n-ethylethylenediamine, l,l-diethoxy-n,n-dimethylmethanamine, 2-methylpyridine, 4-methyl-2-hexanamine, hexylamine, cyclohexylamine, n-ethyl-2-dimethylaminoethylamine, 1,3-propanediamine, 2-

heptanamine, η,η-diethylethylenediamine, 2,6-dimethylpyridine, 4-methylpyridine, η,η'-diethyl-l,2-ethanediamine, dimethylethanolamine.

Preferably, the esters are selected from the group consisting of methyl formate, methylacetate, isopropylformate, ethylacetate, n-propylformate, isopropylacetate, t-butylacetate, ethylpropionate, sec-butyl acetate, diethyl carbonate, n-butylacetate, bromoaceticacidmethylester, methylhexanoate.

De préférence, les éthers sont sélectionnés parmi le groupe consistant en 2,2,2-trifluoroethylmethylether, 1,1,2,2-tetrafluoroethylmethylether, 2-methoxy-l-propene, diethylether, ethoxy-ethene, dimethoxymethane, methylcyclopropylether, 2-ethoxy-propane, methyl-t-butylether, ethyll,l,2,2-tetrafluoroethylether, chloromethoxymethane, diisopropylether, 2-ethoxy-2-methyl-propane, 2-ethoxy-butane, l-methoxy-2-methyl-butane, 2,2-dimethoxypropane, l-ethoxy-2-methylpropane, 1,2-dimethoxyethane, diethoxymethane, di-n-propylether, 1-ethoxybutane, 1-methoxy-pentane, 1,2-dimethoxypropane, isopropyl-isobutyl-ether, 1,1-diethoxyethane, trimethoxymethane, l,l-dichloro-2,2-difluoroethylmethylether, 2,2-diethoxypropane, isobutyl-tert-butylether, sec-butyl-tert-butylether, 1,1-diethoxypropane, 2-methoxyethanol, 2-chloro-l,l-dimethoxyethane, methoxycyclohexane, ethoxyethanol, di-n-butylether, 1-ethoxy-hexane, l-methoxy-2-acetoxypropane, 1,1,1-triethoxyethane.

Preferably, the aldehydes are selected from the group consisting of Acetaldehyde, Ethanedial, isobutanal, Methylglyoxal, 2-methylbutanal, 2,6-dimethyl-5-heptenal, hexanal.

Preferably nitriles are selected from the group consisting of acetonitrile, propionitrile, butyronitrile, valeronitrile, (methyleneamino) acetonitrile.

Preferably, the carbonate is diethyl carbonate.

Preferably the amide is ethanethioamide.

Preferably, the thioalkyl are selected from the group consisting of ethanethiol, dimethylsulfide, 2-propanetiol, 4-methoxy-2-methyl-2-butanethiol, t-butylthiol, 1-propanethiol, thiophene, 2-butanethiol, 2-methyl- l-propanethiol, diethylsulfide, butanethiol, 3 mercapto-2-propanediol, tetrahydrothiophene, tetrahydrothiophene 1-pentanethiol.

Preferably, heterocycles are selected from the group consisting of furan,

1,2-epoxypropane, tetrahydrofurane, dioxane, 1,3-dioxane, piperidine, 1,3,5-trioxane, n-methylmorpholine, 2-methylpyrazine, 1-methylpiperazine, n-ethyl-morpholine, 2,6-dimethylmorpholine, 3-furfural.

Ledit agent d'extraction organique peut être Chloroethane, 3-chloro-l,l,l,2,2,3-hexafluoropropane, 2-chloro-l,l,l,3,3,3-hexafluoropropane, 1,1,1,3,3-pentafluoropropane, ethylamine, bromofluoromethane, l-bromo-l,2-difluoroethylenel-chloro-l, 1,2,3,3,3-hexafluoropropane, l-chloro-l,l,2,2-tetrafluoropropane, acetaldehyde, l-chloro-1,1,2,2,3,3-hexafluoropropane, l,l,l-trifluoro-2-propanone, 2-chloro-l,l,l,2-tetrafluoropropane, 1,1,1,2,3-pentafluoropropane, trichlorofluoromethane, l-chloro-l,l-difluoropropane, 1,1,1-trifluoro-2-bromoethane, l,l-dichloro-2,2,2-trifluoroethane, l-chloro-2,2,3,3,3-pentafluoropropane, l,2-dichloro-l,l,2-trifluoroethane, 2,2,2-trifluoroethylmethylether, 1,1-dichloroethylene, furane, methylformate, isopropylamine, 1,1,2,2-tetrafluoroethylmethylether, 1,1,1,2,3,4, 4,4-octafluorobutane, 2-methoxy-l-propene, diethylether, 1,2-epoxypropane, ethanethiol, 2-chloro-2-fluoropropane, ethoxy-ethene, l-chloro-2,2-difluoroethane, ethylmethylamine, dimethylsulfide, 2-chloropropane, bromoethane, dichloromethane, dimethoxymethane, 2-chloro-l,l,l,3,3-pentafluoropropane, l-chloro-l,2,2-trifluoropropane, iodomethane, 2,2-dichloro-l,l,l,3,3-pentafluoropropane, 2-amino-2-methylpropane, methylcyclopropylether, 3-chloropropene, 3-chloro-l,l,l-trifluoropropane, 1,1,1-trichloro- 2.2.2- trifluoroethane, l,2-dichloro-l,2-difluoroethane, 1,2-dichloro-l, 1,2,3,3-pentafluoropropane, n-propylamine, l,l,2-trichloro-l,2,2-trifluoroethane, 2,2-dimethylbutane, isopropylmethylamine, ethanedial, l,2-dichloro-l,l,3,3,3-pentafluoropropane, 1-chloro-1,2,2,3-tetrafluoropropane, l,l-dichloro-l,2,2,3,3-pentafluoropropane, 2-chloro-2-methylpropane, 3-chloro-l,l,l,3-tetrafluoropropane, 2,3-dichloro-l,l,l,2,3-pentafluoropropane, l,l-dichloro-2,2,3,3,3-pentafluoropropane, 2-chloro-l, 1,1,3-tetrafluoropropane, 2-propanethiol, l,3-dichloro-l,l,2,3,3-pentafluoropropane, 1,2-dichloro- 3.3.3- trifluoropropene, l,3-dichloro-l,l,2,2,3-pentafluoropropane, 1,1,1,2,2,3,4,5,5,5-decafluoropentane, 2-ethoxy-propane, 2,2-dichloro-l,l,l,3-tetrafluoropropane, l-chloro-2,2-difluoropropane, methyl-t-butylether, diethylamine, propanone, methylacetate, 1,1-dichloroethane, ethyll,l,2,2-tetrafluoroethylether, 4-methoxy-2-methyl-2, butanethiol, 2-bromopropane, chloromethoxymethane, l,2-dichloro-l,2,3,3,4,4-hexafluorocyclobutane, 1,1-dichloro-2,2-difluoroethane, 2,2-dichloro-l,l,3,3-tetrafluoropropane, difluorodiethylsilane, 2-butanamine, 2,3-dichloro-l,l,l,2-tetrafluoropropane, n-methylpropylamine, 3-methylpentane, l,l-dichloro-l,2,2,3-tetrafluoropropane, tert-butylthiol, isobutanal, methanol, tetrahydrofurane, l,3-dichloro-l,l,2,2-tetrafluoropropane, l,l,l-trichloro-2,2-difluoroethane, l,2-dichloro-l,2,3,3-tetrafluoropropane, 1-propanethiol, chlorobromomethane, 2-chlorobutane, isopropylformate, diisopropylether, l,3-dichloro-l,l,3,3-tetrafluoropropane, hexane, l,3-dichloro-l,2,2,3-tetrafluoropropane, l,2-dichloro-l,l,2,3-tetrafluoropropane, 3-bromopropene, 2,3-dichloro-l,l,l,3-tetrafluoropropane, l,l-dichloro-2-fluoroethane, 1-bromopropane, l,l-difluoro-l,2,2-trichloroethane, l,l,2-trichloro-l,2-difluoroethane, methylglyoxal, iodoethane, 2-ethoxy-2-methyl-propane, 2-bromo-2-methylpropane, 1,2-dichloro-l-fluoroethane, 1,1,1-trichloroethane, 2,2,2-trifluoroethanol, l-chloro-3-fluoropropane, l,l,l-trifluoro-2-propanol, 2,3-dichloro-l,l,l-trifluoropropane, ethylacetate, 1-butylamine, 1-chlorobutane, ethanol, butanone, 2,4-dimethylpentane, cyclohexane, n-propylformate, 2-ethoxy-butane, acetonitrile, pentafluoro-l-propanol, 2-propanol, tert-butanol, l,3-dichloro-l,l,2-trifluoropropane, l-methoxy-2-methyl-butane, l,l-dichloro-2,2,3-trifluoropropane, cyclohexene, 2,2-dimethoxypropane, l,3,3-trichloro-l,l,2,2-tetrafluoropropane, 2-chloro-2-methyl butane, 1,2-dichloroethane, l-ethoxy-2-methylpropane, diisopropylamine, thiophene, 2-butanethiol, l,l,l-trichloro-2,2,3,3-tetrafluoropropane, 1,2-dimethoxyethane, 3-methyl-2-butanamine, l,l,3-trichloro-l,2,2,3-tetrafluoropropane, 1,3-dichloro-l,2,2-trifluoropropane, diethoxymethane, 1,1-dichloropropane, 2-methyl-l-propanethiol, l,2-dichloro-2-fluoropropane, isopropylacetate, 2-iodopropane, di-n-propylether, 3-pentylamine, n-methylbutylamine, 2-bromobutane, 2,2-difluorotetrachloroethane, diethylsulfide, 1-ethoxybutane, l,l,2,2-tetrachloro-l,2-difluoro-ethane, 1-fluorohexane, l-methoxy-2-propanamine, l,3-dichloro-l,2,3-trifluoropropane, 2,3-dichloro-l-propene, 2-methoxyethanamine, 2,2-difluoroethanol, 2-methylbutanal, 1,2-dichloropropane, propanol, tert-butylacetate, propionitrile, 3-chloropentane, trichloroacetaldehyde, 2-allyloxyethanol, butanethiol, isoamylchloride, 1-methoxy-pentane, ethylpropionate, 2-butanol, 1,2-dimethoxypropane, isopropyl-isobutyl-ether, 1,1,1-trichloro-2,2,3-trifluoropropane, methylcyclohexane, l-chloro-4-fluorobutane, l-bromo-3-fluoropropane, 2,4,4-trimethyl-l-pentene, dioxane, 1-bromobutane, 3-pentanone, 1,1,2-trichloro-2-fluoroethane, 1,1-diethoxyethane, 2-pentanone, 2-methyl-2-butanol, 1-iodopropane, 2-methoxy-lpropanamine, l,l,3-trichloro-l,2,2-trifluoropropane, 1,1,3-trichloro-2,2,3-trifluoropropane, trimethoxymethane, cis-l,3-dichloropropene, 2,2-dichlorobutane, n-pentylamine, l,l-dichloro-2,2-difluoroethylmethylether, 2,2,4-trimethyl-2-pentene, 1,1,1,2-tetrachloro-2-fluoroethane, 1,3-dioxane, 3,3-dimethyl-2, butanone, piperidine, l-bromo-2-chloroethane, isobutanol, 2-bromo-2-methylbutane, dipropylamine, 2,2,3,3-tetraflouro-l-propanol, 2-ethoxyethanamine, triethylfluorosilane, 1-methylcyclohexene, toluène, trans-1,3-dichloropropene, sec-butylacetate, 2-fluorotoluene, 2,2-dimethyl-l-propanol, l,l,l-trichloro-3-fluoropropane, n-methyl-l,2-ethanediamine, 2,2-diethoxypropane, 1,3,5-trioxane, 3,3,3-

trichloro-l-propene, l-chloro-3,3-dimethylbutane, pyridine, 2,3-dimethylhexane, 1,1,1,2-tetrachloro-3,3,3-trifluoropropane, n-methylmorpholine, 3-pentanol, 4-methyl-2-pentanone,

1.2- diaminoethane, isobutyl-tert-butylether, 2-bromopentane, butyronitrile, 1-butanol, 2,3-dichlorobutane, sec-butyl-tert-butylether, l-methoxy2-propanol, 1,1,3,3-tetrachloro, 1,2,2-trifluoropropane, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, perfluorobutanoicacid, l,l,l,3-tetrachloro-2,2,3-trifluoropropane, l-bromo-3-methylbutane, l,3-dichloro-trans-2-butene, l,3-dichloropropane,l-(dimethylamino)-2-propanol, tetrahydrothiophene, 3-methyl-3-pentanol, 1,2-dibromo-l-fluoroethane, 1,1-diethoxypropane, 1,2,2-trichloropropane, 1-chloro-2-methyl-2, propanol, 2-methoxyethanol, 1,2-dichlorobutane, 4,4,4-trifluorobutanol, 2-ethylbutylamine, octane, diethylcarbonate, n-butylacetate, 1-pentanethiol, 1,2,2,3-tetrachloro- 3.3- difluoropropane, 2-chloro-l,l-dimethoxyethane, 2-hexanone, n-ethylethylenediamine, 3-fluoropropanol, 5-hexen-2-one, 2,3-dichloro-2-methylbutane, l,l-diethoxy-n,n-dimethylmethanamine, 2-methylpyridine, 1-bromopentane, 2-methoxyl-propanol, 1,2-dichloro-2-butene, 1-iodobutane, l-ethoxy-2-propanol, hexanal, 4-methyl-2-pentanol, 1,2-dibromoethane, chlorobenzene, ethylcyclohexane, bromoaceticacidmethylester, 1,1,2-trichloropropane, 1,2-octanediol, 4-methyl-2-hexanamine, hexylamine, 2-chloro-l-propanol, methoxycyclohexane, 2-(dimethylamino)-ethanol, 1,3-dichlorobutane, cyclohexylamine, n-ethyl-2-dimethylaminoethylamine, ethoxyethanol, 3-hexanol, 2-hexanol, ethylbenzene, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-pentanol, 1-methylpiperazine, n-ethyl-morpholine, 1,4-dimethylbenzene, 1,3-dimethylbenzene, 1,3-propanediamine, di-n-butylether, 3,3,4,4,5,5,6,6-octafluoro-l-pentanol, valeronitrile, (methyleneamino)acetonitrile, 1,2-dibromopropane, 2-heptanamine, 1,2,3-trimethylcyclohexane, 2,3-dimethylbutanol, 1-ethoxy-hexane, l-chloro-3-bromopropane, 3-furfural, η,η-diethylethylenediamine, 2,6-dimethylpyridine, 1,1,3,3-tetrachloro-l-fluoropropane, 4-methyl-2-hexanone, 1,2-dimethylbenzene, 1,1,2,2,3-pentchloro-3,3-difluoropropane, l-methoxy-2-acetoxypropane, 1,1,1-triethoxyethane, styrene, 4-methylpyridine, n,n'-diethyl-l,2-ethanediamine, 2,6-dimethylmorpholine, 2-ethyl-l-butanol, 1,2-dichloropentane, 2-methyl-l-pentanol, methylhexanoate, 2-propoxyethanol, dimethylethanolamine, l-propoxy-2-propanol.

Advantageously, said organic extractant may be chloroethane, 1,1,1,3,3-pentafluoropropane, bromofluoromethane, l-bromo-l, 2-difluoroethylene, l-chloro-1,1,2,2-tetrafluoropropane, acetaldehyde, l, l, l-trifluoro-2-propanone, 2-chloro-l, l, l, 2-tetrafluoropropane, 1,1,1,2,3-pentafluoropropane, l-chloro-l-difluoropropane, 1,1,1-trifluoro-2-bromoethane, l, l-dichloro-2,2,2-trifluoroethane, l-chloro-2,2,3,3,3

pentafluoropropane, l,2-dichloro-l,l,2-trifluoroethane, 2,2,2-trifluoroethylmethylether, furane, methylformate, isopropylamine, 1,1,2,2-tetrafluoroethylmethylether, 2-methoxy-l-propene, diethylether, 1,2-epoxypropane, ethanethiol, 2-chloro-2-fluoropropane, ethoxy-ethene, l-chloro-2,2-difluoroethane, ethylmethylamine, dimethylsulfide, 2-chloropropane, bromoethane, dimethoxymethane, 2-chloro-l,l,l,3,3-pentafluoropropane, l-chloro-1,2,2-trifluoropropane, 2,2-dichloro-l,l,l,3,3-pentafluoropropane, 2-amino-2-methylpropane, methylcyclopropylether, 3-chloropropene, 3-chloro-l,l,l-trifluoropropane, 1,1,1-trichloro-2,2,2-trifluoroethane, l,2-dichloro-l,2-difluoroethane, 1,2-dichloro-l, 1,2,3,3-pentafluoropropane, l,l,2-trichloro-l,2,2-trifluoroethane, isopropylmethylamine, ethanedial, l,2-dichloro-l,l,3,3,3-pentafluoropropane, l-chloro-l,2,2,3-tetrafluoropropane, 1,1-dichloro-1,2,2,3,3-pentafluoropropane, 2-chloro-2-methylpropane, 3-chloro-l,l,l,3-tetrafluoropropane, 2,3-dichloro-l,l,l,2,3-pentafluoropropane, l,l-dichloro-2,2,3,3,3-pentafluoropropane, 2-chloro-l,l,l,3-tetrafluoropropane, 2-propanethiol, l,2-dichloro-3,3,3-trifluoropropene, 2-ethoxy-propane, 2,2-dichloro-l,l,l,3-tetrafluoropropane, l-chloro-2,2-difluoropropane, methyl-t-butylether, diethylamine, propanone, methylacetate, ethyll,l,2,2-tetrafluoroethylether, 4-methoxy-2-methyl-2-butanethiol, 2-bromopropane, l,l-dichloro-2,2-difluoroethane, 2,2-dichloro-l,l,3,3-tetrafluoropropane, difluorodiethylsilane, 2,3-dichloro-1,1,1,2-tetrafluoropropane, l,l-dichloro-l,2,2,3-tetrafluoropropane, tert-butylthiol, isobutanal, tetrahydrofurane, l,3-dichloro-l,l,2,2-tetrafluoropropane, l,l,l-trichloro-2,2-difluoroethane, l,2-dichloro-l,2,3,3-tetrafluoropropane, 1-propanethiol, 2-chlorobutane, isopropylformate, diisopropylether, l,3-dichloro-l,2,2,3-tetrafluoropropane, 1,2-dichloro-l, 1,2,3-tetrafluoropropane, 2,3-dichloro-l,l,l,3-tetrafluoropropane, 1-bromopropane, 1,1-difluoro-1,2,2-trichloroethane, l,l,2-trichloro-l,2-difluoroethane, methylglyoxal, 2-ethoxy-2-methyl-propane, 2-bromo-2-methylpropane, l-chloro-3-fluoropropane, l,l,l-trifluoro-2-propanol, 2,3-dichloro-l,l,l-trifluoropropane, ethylacetate, 1-chlorobutane, butanone, n-propylformate, 2-ethoxy-butane, pentafluoro-l-propanol, tert-butanol, l,3-dichloro-l,l,2-trifluoropropane, 1-methoxy-2-methyl-butane, l,l-dichloro-2,2,3-trifluoropropane, cyclohexene, 2,2-dimethoxypropane, l,3,3-trichloro-l,l,2,2-tetrafluoropropane, 2-chloro-2-methylbutane, 1-ethoxy-2-methylpropane, diisopropylamine, 2-butanethiol, l,l,l-trichloro-2,2,3,3-tetrafluoropropane, 1,2-dimethoxyethane, l,l,3-trichloro-l,2,2,3-tetrafluoropropane, 1,3-dichloro-l,2,2-trifluoropropane, diethoxymethane, 2-methyl-l-propanethiol, isopropylacetate, 2-iodopropane, di-n-propylether, 2-bromobutane, diethylsulfide, 1-ethoxybutane, 1-fluorohexane, l-methoxy-2-propanamine, l,3-dichloro-l,2,3-trifluoropropane, 2-

methoxyethanamine, 2-methylbutanal, tert-butylacetate, propionitrile, 3-chloropentane, 2-allyloxyethanol, butanethiol, isoamylchloride, 1-methoxy-pentane, ethylpropionate, 2-butanol, 1,2-dimethoxypropane, isopropyl-isobutyl-ether, l,l,l-trichloro-2,2,3-trifluoropropane, 1-chloro-4-fluorobutane, l-bromo-3-fluoropropane, 2,4,4-trimethyl-l-pentene, dioxane, 1-bromobutane, 3-pentanone, 1,1-diethoxyethane, 2-pentanone, 2-methyl-2-butanol, 2-methoxy-lpropanamine, l,l,3-trichloro-l,2,2-trifluoropropane, l,l,3-trichloro-2,2,3-trifluoropropane, trimethoxymethane, l,l-dichloro-2,2-difluoroethylmethylether, 2,2,4-trimethyl-2-pentene, 1,3-dioxane, 3,3-dimethyl-2-butanone, piperidine, 2-bromo-2-methylbutane, dipropylamine, 2,2,3,3-tetraflouro-l-propanol, 2-ethoxyethanamine, triethylfluorosilane, 1-methylcyclohexene, toluène, sec-butylacetate, 2-fluorotoluene, 2,2-dimethyl-l-propanol, n-methyl-l,2-ethanediamine, 2,2-diethoxypropane, 1,3,5-trioxane, 1-chloro-3,3-dimethylbutane, pyridine, l,l,l,2-tetrachloro-3,3,3-trifluoropropane, n-methylmorpholine, 3-pentanol, 4-methyl-2-pentanone, 1,2-diaminoethane, isobutyl-tert-butylether, 2-bromopentane, butyronitrile, 1-butanol, sec-butyl-tert-butylether, l-methoxy2-propanol, l,l,3,3-tetrachloro-l,2,2-trifluoropropane, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, l,l,l,3-tetrachloro-2,2,3-trifluoropropane, l-bromo-3-methylbutane, 1-(dimethylamino)-2-propanol, tetrahydrothiophene, 3-methyl-3-pentanol, 1,1-diethoxypropane, 2-methoxyethanol, 4,4,4-trifluorobutanol, diethylcarbonate, n-butylacetate, 1-pentanethiol, 2-chloro-l,l-dimethoxyethane, 2-hexanone, n-ethylethylenediamine, 5-hexen-2-one, 1,1-diethoxy-n,n-dimethylmethanamine, 2-methylpyridine, 1-bromopentane, 2-methoxyl-propanol, l-ethoxy-2-propanol, hexanal, 4-methyl-2-pentanol, 1,2-octanediol, methoxycyclohexane, 2-(dimethylamino)-ethanol, cyclohexylamine, n-ethyl-2-dimethylaminoethylamine, ethoxyethanol, 3-hexanol, 2-hexanol, ethylbenzene, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-pentanol, 1-methylpiperazine, n-ethyl-morpholine, 1,4-dimethylbenzene, 1,3-dimethylbenzene, 1,3-propanediamine, di-n-butylether, 3,3,4,4,5,5,6,6-octafluoro-l-pentanol, valeronitrile, (methyleneamino)acetonitrile, 2,3-dimethylbutanol, 1-ethoxy-hexane, 3-furfural, 2,6-dimethylpyridine, 4-methyl-2-hexanone, 1,2-dimethylbenzene, l-methoxy-2-acetoxypropane, 1,1,1-triethoxyethane, styrène, 4-methylpyridine, n,n'-diethyl-1,2-ethanediamine, 2,6-dimethylmorpholine, 2-ethyl-l-butanol, 2-methyl-l-pentanol, methylhexanoate, 2-propoxyethanol, dimethylethanolamine, l-propoxy-2-propanol.

De préférence, ledit agent d'extraction organique peut être Acetaldehyde, methylformate, 2-methoxy-l-propene, 1,2-epoxypropane, ethoxy-ethene, dimethoxymethane, l-chloro-l,2,2-trifluoropropane, 3-chloro-l,l,l-trifluoropropane, ethanedial, 2-chloro-l, 1,1,3- tetrafluoropropane, propanone, methylacetate, 4-methoxy-2-methyl-2-butanethiol, difluorodiethylsilane, isobutanal, isopropylformate, methylglyoxal, 2,3-dichloro-l,l,l-trifluoropropane, ethylacetate, butanone, n-propylformate, l,3-dichloro-l,l,2-trifluoropropane, l,l-dichloro-2,2,3-trifluoropropane, 1,2-dimethoxyethane, 1,3-dichloro-1,2,2-trifluoropropane, isopropylacetate, diethylsulfide, l,3-dichloro-l,2,3-trifluoropropane, 2-methylbutanal, 2-allyloxyethanol, ethylpropionate, 1,2-dimethoxypropane, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3-dioxane, 3,3-dimethyl-2-butanone, pyridine, n-methylmorpholine, 4-methyl-2-pentanone, butyronitrile, l-methoxy2-propanol, diethylcarbonate, n-butylacetate, 2-hexanone, 5-hexen-2-one, 2-methoxyl-propanol, 1-ethoxy-2-propanol, hexanal, 2-(dimethylamino)-ethanol, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-methylpiperazine, n-ethyl-morpholine, valeronitrile, 4-methyl-2-hexanone, l-methoxy-2-acetoxypropane, 2,6-dimethylmorpholine, methylhexanoate, 2-propoxyethanol, l-propoxy-2-propanol.

En particulier, ledit agent d'extraction organique peut être 2-methoxy-l-propenej 1,2-epoxypropanej ethoxy-ethene, dimethoxymethane, methylacetate, isobutanal, isopropylformate, ethylacetate, butanone, n-propylformate, 1,2-dimethoxyethane, isopropylacetate, 2-methylbutanal, ethylpropionate, 1,2-dimethoxypropane, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3-dioxane, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, diethylcarbonate, n-butylacetate, 2-hexanone, 5-hexen-2-one, 1-ethoxy-2-propanol, hexanal, 2-(dimethylamino)-ethanol, 2-methylpyrazine, 1-methylpiperazine, valeronitrile, 4-methyl-2-hexanone, l-methoxy-2-acetoxypropane, 2,6-dimethylmorpholine, methylhexanoate, l-propoxy-2-propanol.

The organic extraction agent to be used can be selected depending on the compounds present in said first composition. Thus, the organic extractant may be selected depending on the separation factor and the absorption capacity determined for a particular composition. Besides these two criteria, the choice of organic extraction agent can optionally be based on other commercial or environmental criteria, such as for example the cost of organic extraction agent, the availability on the market, its flammable or toxic properties. In addition, according to a particular embodiment, in order to optimize the operation of the distillation columns used in step b) and c) of this process for purification of 2,3,3,3-tetrafluoro-l-propene, the boiling point of the organic extractant may be from 10 ° C to 200 ° C, preferably from 10 ° C to 190 ° C, preferably 10 ° C

to 180 ° C, especially 10 ° C to 170 ° C, more preferably from 10 ° C to 160 ° C, and preferentially from 10 ° C to 150 ° C.

According to a preferred embodiment, said organic extractant has a separation factor If two greater than or equal to 1.1, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (Y2, s * P2) wherein

Yi, s represents the coefficient of activity of 2,3,3,3-tetrafluoro-l-propene in said organic extractant at infinite dilution,

IP is the saturation vapor pressure of 2,3,3,3-tetrafluoro-l-propene, Y2, s represents the coefficient of activity of a compound consisting of chloromethane (40), 1,1-difluoroethane (152a ), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans-1,2,3,3 , 3-pentafluoropropene (1225ye-E) and 3,3,3-trifluoropropene (1243zf) in said organic extractant at infinite dilution; preferably the activity coefficient of the 3,3,3-trifluoropropene (1243zf) or trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E),

P2 represents the saturation vapor pressure of one of the compounds consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), trans- 1,2,3,3,3-pentafluoropropene (1225ye-E) and 3,3,3-trifluoropropene (1243zf); preferably the saturated vapor pressure of 3,3,3-trifluoropropene (1243zf) or trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E).

Advantageously, the separation factor If 2 is greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, particularly greater than or equal to 2.0.

claims

A process for purifying 2,3,3,3-tetrafluoro-l-propene (1234yf) from a first composition comprising 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a ), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), said method comprising the steps of:

a) contacting said first composition with at least one organic extractant to form a second composition;

b) extractive distillation of said second composition to form:

i) a third composition comprising said organic extractant, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E) and optionally or not at least a compound selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-2,3,3, 3-pentafluoropropene (1225ye-E); and

ii) a stream comprising 2,3,3,3-tetrafluoro-l-propene, c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising 3,3,3 trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E) and optionally or not at least one compound selected from the group consisting of chloromethane (40), 1,1- difluoroethane ( 152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a) and trans-l, 2,3,3,3-pentafluoropropene (1225ye-E); preferably the stream comprising said organic extractant is recycled to step a).

2. Method according to the preceding claim characterized in that said organic extractant is a solvent selected from the group consisting of hydrocarbon, hydrohalocarbure, alcohol, ketone, amine, ester, ether, aldehyde, nitrile, carbonate, thioalkyl, amide and heterocyclic ring; or said organic extractant is difluoroéthylsilane, triethylfluorosilane or perfluorobutanoic acid; preferably said organic extractant is a solvent selected from the group consisting of ketone, ester, aldehyde, ether, carbonate, and heterocycle.

3. A method according to any one of claims characterized in that the organic extractant has a boiling point between 10 and 150 ° C.

4. A method according to any preceding claim characterized in that said organic extractant has a separation factor If two greater than or equal to 1.1, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein

yi, s represents the coefficient of activity of 2,3,3,3-tetrafluoro-l-propene in said organic extractant at infinite dilution,

IP is the saturation vapor pressure of 2,3,3,3-tetrafluoro-l-propene,

Y2, s represents the coefficient of activity of the 3,3,3-trifluoropropene (1243zf) or trans 1,3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant in infinite dilution;

P2 represents the saturation vapor pressure of 3,3,3-trifluoropropene (1243zf) or trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E);

preferably, the separation factor is greater than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8, greater than or equal 2.0.

5. A method according to any preceding claim characterized in that said organic extractant has an absorption capacity C2, s greater than or equal to 0.20, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s is the activity coefficient of the 3,3,3-trifluoropropene (1243zf) or trans-l, 3,3,3-tetrafluoro-l-propene (1234ze -E) in said organic extractant at infinite dilution;

advantageously C2 absorption capacity, s is greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0.

A method according to any preceding claim characterized in that said organic extractant has a separation factor If two greater than or equal to 1.1, said separation factor is calculated by the formula Si, 2 = (yi , s * PI) / (y2, s * P2) wherein yi, s represents the coefficient of activity of 2,3,3,3-tetrafluoro-l-propene in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 2,3,3,3-tetrafluoro-l-propene, y2, s is the activity coefficient of the 3,3,3-trifluoropropene (1243zf) in said organic extractant in dilution infinite and P 2 is the saturation vapor pressure of 3,3,3-trifluoropropene (1243zf);

and

said organic extractant has a separation factor If two greater than or equal to 1.1, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein yi, s represents the coefficient of activity of 2,3,3,3-tetrafluoro-l-propene in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 2,3,3, 3-tetrafluoro-l-propene, y2, s represents the coefficient of activity of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution and P2 represents the saturation vapor pressure of the trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E); advantageously, said organic extractant has a higher separation factor than or equal to 1.2, preferably greater than or equal to 1.4, more preferably greater than or equal to 1.6, in particular greater than or equal to 1.8 , greater than or equal to 2.0.

7. A method according to any one of claims characterized in that said organic extractant has an absorption capacity C2, s greater than or equal to 0.20, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s is the activity coefficient of the 3,3,3-trifluoropropene (1243zf) in said organic extractant at infinite dilution;

and

said organic extractant has an absorption capacity C2, s greater than or equal to 0.20, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s represents the activity coefficient of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution;

advantageously C2 absorbency, s is greater than or equal to 0.40, preferably greater than or equal to 0.60, more preferably greater than or equal to 0.80, in particular greater than or equal to 1.0.

A method according to any preceding claim characterized in that said first composition is an azeotropic composition or quasi-azeotropic comprising 2,3,3,3-tetrafluoro-l-propene, trans-3,3,3-tetrafluoro -l-propene (1234ze-E), 3,3,3-trifluoropropene (1243zf) and optionally or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E).

A method according to any preceding claim characterized in that said organic extractant is selected from the group consisting of 2-methoxy-l-propene j l, 2-epoxypropane j ethoxy-ethene, dimethoxymethane, methyl acetate, isobutanal, isopropylformate, ethylacetate, butanone, n-propylformate, 1,2-dimethoxyethane, isopropyl acetate, 2-methylbutanal, ethylpropionate, 1,2-dimethoxypropane, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3-dioxane, 3, 3-dimethyl-2-butanone, 4-methyl-2-pentanone, diethyl carbonate, n-butylacetate, 2-hexanone, 5-hexen-2-one, l-ethoxy-2-propanol, hexanal, 2- (dimethylamino) - ethanol, 2-methylpyrazine, 1-methylpiperazine, valeronitrile, 4-methyl-2-hexanone, l-methoxy-2-acetoxypropane, 2,6-dimethylmorpholine, methylhexanoate, l-propoxy-2-propanol; preferably said organic extractant is selected from the group consisting of ethoxy-ethene, dimethoxymethane, methyl acetate, isobutanal, isopropylformate, ethylacetate, butanone, 1,2-dimethoxyethane, isopropyl acetate, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3-dioxane, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, diethyl carbonate, n-butyl acetate, l-ethoxy-2-propanol, hexanal; preferably said organic extractant is selected from the group consisting of dimethoxymethane, butanone, isopropyl acetate, dioxane, trimethoxymethane, 1,3-dioxane, n-butyl acetate, l-ethoxy-2-propanol, hexanal; in particular said organic extractant is selected from the group consisting of dimethoxymethane, isopropylacetate, dioxane, trimethoxymethane, 1,3-dioxane, n-butyl acetate, 1-ethoxy-2-propanol, hexanal.

10. A method according to any preceding claim characterized in that the stream comprising 2,3,3,3-tetrafluoro-l-propene formed in step b) is recovered and is free of trans-3 , 3,3-tetrafluoro-l-propene (1234ze-E) and / or 3,3,3-trifluoropropene (1243zf) and / or at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-1,2,3,3,3-pentafluoropropene (1225ye-E).

11. A method according to any preceding claim characterized in that said first composition comprises impurities having a boiling point below the boiling point of 2,3,3,3-tetrafluoro-l-propene and optionally heavy impurities, the method comprising prior to step a) the steps of: i ') implementation or providing a composition comprising 2,3,3,3-tetrafluoro-l-propene, impurities having a boiling point of lower boiling at the boiling point of 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze -E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115),

1.1.1.2- tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye- E), and optionally the heavy impurities;

ii ') distillation of said composition of step i) to remove the top of column impurities having a boiling point below the boiling point of the

2.3.3.3- tetrafluoro-l-propene, and form a first stream comprising 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-3,3,3 tetrafluoro-1-propene (1234ze-E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1 , 2-tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), and optionally the heavy impurities; recovered at the bottom of distillation column;

iii ') optionally, distilling said first stream recovered at the bottom of distillation column in step ii') to retrieve the column head a second stream comprising 2,3,3,3-tetrafluoro-l-propene, 3, 3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a), trans-l, 2,3,3,3-pentafluoropropene (1225ye- E), and bottom distillation column a stream comprising the heavy impurities;

said first stream recovered in step ii ') or said second stream recovered in step iii') corresponding to said first composition implemented in step a).

12. A process for production and purification of 2,3,3,3-tetrafluoro-l-propene comprising the steps of:

A) fluorination in the presence of a catalyst of a compound of formula (I) CX (Y) 2-CX (Y) m - CHmXY wherein X and Y independently represent a hydrogen, fluorine or chlorine and m = 0 or 1 and / or fluorination in the presence of a catalyst of a compound of formula (CXnY3-n) CHpXi pCH- m X 2-m (II) wherein X is independently of each other Cl, F, I or Br; Y is independently of each other H, Cl, F, I or Br; n is 1, 2 or 3; and m is 0, 1 or 2; and p is 0 or 1;

B) recovering a stream comprising 2,3,3,3-tetrafluoro-l-propene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene ( 1234ze-E), and optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a ), trans-l, 2,3,3,3-pentafluoropropene (1225ye- E);

C) implementing the method according to any one of claims 1 to 9 from the stream recovered in step B).

13. A composition comprising 2,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene (1243zf), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and one of organic extractant having:

a separation factor If two greater than or equal to 1.40, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein yi, s represents the activity coefficient of 2,3,3,3-tetrafluoropropene in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 2,3,3,3-tetrafluoropropene, y2, s represents the coefficient of activity of the 3,3,3-trifluoropropene (1243zf) in said organic extractant at infinite dilution, P2 represents the saturation vapor pressure of 3,3,3-trifluoropropene (1243zf) and

a separation factor If two greater than or equal to 1.40, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2) wherein yi, s represents the activity coefficient of 2,3,3,3-tetrafluoropropene in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 2,3,3,3-tetrafluoropropene, y2, s represents the coefficient of activity of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution, P2 represents the saturation vapor pressure of the trans-3,3, 3-tetrafluoro-l-propene (1234ze-E);

preferably said organic extractant has:

an absorption capacity C2, s greater than 0.60, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s represents the coefficient of activity of 3.3 , 3-trifluoropropene (1243zf) in said organic extractant at infinite dilution; and a capacitor C2 absorption, s greater than 0.60, said absorptive capacity is calculated by the formula C2, s = l / (y2, s) wherein y2, s is the activity coefficient of the trans- l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution,

more preferably, the composition optionally includes or not at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), chloropentafluoroethane (115), 1,1,1,2-tetrafluoroethane (134a ), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E).

14. A composition according to claim 13 characterized in that the organic extractant is selected from the group consisting of acetaldehyde, methyl formate, 2-methoxy-l-propene, 1,2-epoxypropane, ethoxy-ethene, dimethoxymethane, 1 -

chloro-l,2,2-trifluoropropane, 3-chloro-l,l,l-trifluoropropane, ethanedial, 2-chloro- 1,1,1,3-tetrafluoropropane, propanone, methylacetate, 4-methoxy-2-methyl-2- butanethiol, difluorodiethylsilane, isobutanal, isopropylformate, methylglyoxal, 2,3- dichloro-l,l,l-trifluoropropane, ethylacetate, butanone, n-propylformate, 1,3- dichloro-l,l,2-trifluoropropane, l,l-dichloro-2,2,3-trifluoropropane, 1,2- dimethoxyethane, l,3-dichloro-l,2,2-trifluoropropane, isopropylacetate, diethylsulfide, l,3-dichloro-l,2,3-trifluoropropane, 2-methylbutanal, 2-allyloxyethanol, ethylpropionate, 1,2-dimethoxypropane, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3-dioxane, 3,3-dimethyl-2-butanone, pyridine, n- methylmorpholine, 4-methyl-2-pentanone, butyronitrile, l-methoxy2-propanol, diethylcarbonate, n-butylacetate, 2-hexanone, 5-hexen-2-one, 2-methoxyl-propanol, l-ethoxy-2-propanol, hexanal, 2-(dimethylamino)-ethanol, 2-methylpyrazine, 2-ethoxy- 1- propanol, 1-methylpiperazine, n-ethyl-morpholine, valeronitrile, 4-methyl-2- hexanone, l-methoxy-2-acetoxypropane, 2,6-dimethylmorpholine, methylhexanoate,

2- propoxyethanol, l-propoxy-2-propanol.

15. Composition selon la revendication 13 ou 14 caractérisée en ce que ledit agent d'extraction organique est sélectionné parmi le groupe consistant en 2-methoxy-l- propenej l,2-epoxypropanej ethoxy-ethene, dimethoxymethane, methylacetate, isobutanal, isopropylformate, ethylacetate, butanone, n-propylformate, 1,2- dimethoxyethane, isopropylacetate, 2-methylbutanal, ethylpropionate, 1,2- dimethoxypropane, dioxane, 3-pentanone, 2-pentanone, trimethoxymethane, 1,3- dioxane, 3,3-dimethyl-2-butanone, 4-methyl-2-pentanone, diethylcarbonate, n- butylacetate, 2-hexanone, 5-hexen-2-one, l-ethoxy-2-propanol, hexanal, 2- (dimethylamino)-ethanol, 2-methylpyrazine, 1-methylpiperazine, valeronitrile, 4- methyl-2-hexanone, l-methoxy-2-acetoxypropane, 2,6-dimethylmorpholine, methylhexanoate, l-propoxy-2-propanol.