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.
BACKGROND OF THE INVENTION
Hydrofluorocarbons (HFCs) and particularly hydrofluoroolefins (HFOs), such as 2,3,3,3-tetrafluoro-l-propene (HFO-1234yf) are compounds known for their properties of refrigerants 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. This type of reaction is carried out in the gas phase and generates impurities that must therefore be 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 the trans-l, 3,3,3-tetrafluoro-l -propene (1234ze-E) is observed. Byproducts such as for example 1,1,1,2,2-pentafluoropropene are also trained. Purification of this type of reaction may be effected for example by 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.
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.
Summary of the Invention
The present invention allows the purification of 2,3,3,3-tetrafluoro-l-propene. The present invention allows in particular to obtain a stream comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane having a low content of trans-1, 3,3,3-tetrafluoro-l-propene (1234ze-E). The present invention thus allows 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, 1,1,1,2,2-pentafluoropropane (245cb) and trans-1,3,3,3-tetrafluoro-l-propene (1234ze-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 and trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E); and ii) a stream comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2- pentafluoropropane (245cb),

c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E).

Preferably the separation of step c) is performed by distillation. Preferably, the stream comprising said organic extractant is recycled to step a). Preferably the stream comprising trans-l, 3,3,3-tetrafluoro-l-propene is purified or disposed of by incineration.

Preferably, the current ii) comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane (245cb) formed in step b) is recovered. The stream may be purified to separate 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane (245cb). Thus, according to a preferred embodiment, the method also comprises a step of recovering

said stream comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane (245cb) obtained in stage b) and distillation thereof to form a stream comprising a 2,3,3,3-tetrafluoro-l-propene and a stream B comprising 1,1,1,2,2-pentafluoropropane (245cb). Stream B comprising 1,1,1,2,2-pentafluoropropane (245cb) can be recycled to step A) of the method of production and purification of 2,3,3,3-tetrafluoro-l-propene described -Dessous. The stream A comprising 2,3,3,3-tetrafluoro-l-propene may be purified to a purity degree complying with commercial specifications, ie devoid of or having a low content of 1,1,1,2,2- pentafluoropropane or trans-l, 3,3,3-tetrafluoro-1-propene.

According to a preferred embodiment, said first composition further comprises at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3-pentafluoropropene (1225ye-Z) and 3,3,3-trifluoropropene (1243zf).

According to a preferred embodiment, said at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115) , trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf) are also contained in said second and third compositions; step c) of this process is the recovery and separation of said third composition between firstly a stream comprising said organic extractant and also a stream comprising the trans-3,3,3 -tetrafluoro-l-propene (1234ze-E) and said at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a) , chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3 trifluoropropene (1243zf).

Preferably, said organic extractant may have a boiling point between 10 and 150 ° C.

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

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 is the activity coefficient 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-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.

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 said at least one of the compounds consisting of trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution , preferably Y 2, s represents the coefficient of activity of said at least one of the compounds consisting of trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), in said organic extractant in dilution infinite;

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 also 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 * P1) / (Y2, S * P2) wherein

Yi, s is the activity coefficient of 1, 1, 1,2,2-pentafluoropropane (245cb) in said organic extractant at infinite dilution,

IP is the saturated vapor pressure of 1,1, 1,2,2-pentafluoropropane (245cb), 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,

P2 represents the saturation vapor pressure of the 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 first composition may comprise 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), 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), 1,1,1,2-tetrafluoroethane ( 134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3.3, 3-trifluoropropene (1243zf).

According to a preferred embodiment, said organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, propanone, methyl acetate, butanone, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tert-butyl acetate, dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butyl acetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, n- Butylacetate, 2-methoxy-l-propanol, hexanal. Preferably, said organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, diethoxymethane, isopropylacetate, 3-pentylamine,

2- methoxyethanamine, tert-butylacetate, dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, n-butylacetate, 2-methoxy-l-propanol, hexanal.

According to a preferred embodiment, the stream comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane (245cb) formed in step b) is recovered and is devoid of trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E).

According to a preferred embodiment, the method comprises, prior to step a) the steps of:

i ') implementation of a composition comprising 2,3,3,3-tetrafluoro-l-propene, impurities having a boiling point below the boiling point of 2,3,3,3-tetrafluoro- l-propene, 1,1,1,2,2-pentafluoropropane (245cb) and trans- 1,3,3,3-tetrafluoro-l-propene (1234ze-E), optionally or not at least one of the selected compounds from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (E-1225ye),

cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), and optionally or non-heavy impurities;

ϋ ') 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, 1,1,1,2,2-pentafluoropropane (245cb) and trans-1,3,3,3-tetrafluoro-l-propene (1234ze -E), optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), and optionally or not heavy impurities, recovered at the bottom of distillation column;

iii ') optionally or not, 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, 1,1,1,2,2- pentafluoropropane (245cb) and trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), optionally or not at least one of compounds selected from the group consisting of in methyl chloride (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E ), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), and 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.

According to a second aspect, the invention provides a process for production and purification of 2,3,3,3-tetrafluoro-l-propene comprising the steps of:

A) fluorination and / or in the presence of a catalyst a compound of the formula CX (Y) 2-CX (Y) m - CH m XY (I) wherein X and Y are independently H, F, or Cl and m = 0 or 1; and / or catalytic fluorination in the presence of a catalyst of a compound of formula (CX n Y 3-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, 1,1,1,2,2- pentafluoropropane (245cb), 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), 1,1,1,2-tetrafluoroethane (134a) , chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3 trifluoropropene (1243zf);

C) implementation of the purification process of the 2,3,3,3-tetrafluoro-l-propene according to the present invention from the stream recovered in step B).

According to another aspect, the present invention provides a composition comprising 2,3,3,3-tetrafluoropropene, 1,1,1,2,2-pentafluoropropane (245cb), 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 1.60, said separation factor is calculated by the formula Si, 2 = (yi, s * Pl ) / (y2, s * P2) wherein yi, s is 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 is the activity coefficient 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-1,3,3,3-tetrafluoro-l-propene (1234ze-E); and said organic extractant having a separation factor If two greater than or equal to 1.60, said separation factor is calculated by the formula Si, 2 = (Yi, s * PI) / (y2, s * P2 ) wherein yi, s is the activity coefficient of 1,1,1,2,2-pentafluoropropane (245cb) in said organic extractant at infinite dilution, PI represents the saturation vapor pressure of 1.1, 1,2,2-pentafluoropropane (245cb), y2, s is the activity coefficient of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant in dilution infinite, P2 represents the saturation vapor pressure of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) preferably said organic extractant has a C2 absorbency, s greater than or equal 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 ledi t organic extractant at infinite dilution. According to a preferred embodiment, said organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, propanone, methyl acetate, butanone, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tert-butyl acetate, dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butyl acetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, n- Butylacetate, 2-methoxy-l-propanol, hexanal. Preferably, said organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tert-butyl acetate, dioxane, 1,1- diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butyl acetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, n-butylacetate, 2-methoxy-l-propanol, hexanal. Preferably, said composition according to this further aspect of the invention is free of HF.

BRIEF DESCRIPTION OF FIGURES

Figs la-c show schematically a device for implementing a process for purifying 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, C2-C20, C3-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 alkene, C2-C20 refers to hydrocarbon compounds containing one or more double carbon-carbon bonds and having 2 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

of carbon. Cycloalkene term C3-C20 refers to cyclic hydrocarbon compounds containing from 3 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, C 1 -C 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 , -NR a C (0) R b , -C (0) NR a R b , R a and R b may form with the nitrogen atom or with the functional group to which they are attached, a saturated or unsaturated, aromatic or nonaromatic, comprising from 4 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 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, 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" is 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 the formula R c C (0) NR e R d wherein R c and

R d are as defined above, R e is selected from the same substituents as those defining 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, of

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" denotes a carbon ring having 4 to 10 ring members of which at least is one of the links one 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, -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 as defined above.

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, 1,1,1,2,2-pentafluoropropane (245cb) and trans-3, 3,3-tetrafluoro-l-propene (1234ze-E).

Preferably, said method comprises 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 trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and ii) a stream comprising 2,3,3,3-tetrafluoroethane l-propene and 1,1,1,2,2- pentafluoropropane (245cb)

c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E).

Preferably, the stream comprising said organic extractant is recycled to step a). Preferably, the stream comprising trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) is purified or disposed of by incineration.

Preferably, said method also comprises a current from said recovering step comprising 2,3,3,3-tetrafluoro-l-propene (1234yf) and 1,1,1,2,2-pentafluoropropane (245cb) obtained in stage b) and distillation thereof to form a stream a comprising 2,3,3,3-tetrafluoro-l-propene and a stream B comprising 1,1,1,2,2-pentafluoropropane (245cb).

Said first composition may comprise 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2,2-pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) and at least one of the compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans -1,2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf). Preferably, the first 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), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3, 3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf).

When said first composition contains at least one compound selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans- l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), the latter or they are contained in said second and third compositions.

Step c) of this method may thus consist in recovering said third composition and the separation between firstly said organic extractant and the other the trans-l, 3,3,3-tetrafluoro- l-propene (1234ze-E) and said at least one compound selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane ( 115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf ).

Said first composition may comprise between 50 and 99% by weight of 2,3,3,3-tetrafluoro-l-propene based on the total weight of the first composition, preferably

between 50 and 95% by weight, preferably between 55 and 90% and especially between 60 and 80% 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 0.1 and 50% by weight 1,1,1,2,2-pentafluoropropane (245cb) based on the total weight of the first composition, preferably between 0.1 and 49 , 9% by weight, preferably between 1 and 45% by weight, more preferably between 2 and 40% and in particular between 5 and 40% by weight of 1,1,1,2,2-pentafluoropropane (245cb) according the total weight of the first composition.

When it contains, said first composition may comprise between 0.1 and 50% by weight trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) based on the total weight of the first composition, preferably between 0.1 and 49.9% by weight, preferably between 0.5 and 40% by weight, more preferably between 1 and 30% and in particular between 5 and 25% 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 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 5 and 2000 ppm, in particular from 10 and 1000 ppm by weight of methyl chloride (40) 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-difluoroethane (152a) based on the total weight of the first composition, advantageously between 1 and 1000 ppm by weight, preferably between 5 and 500 ppm and in particular between 10 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 less than 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 5 and 500 ppm and in particular between 10 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 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 5 and 500 ppm and in particular between 10 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 2000 ppm by weight trans-l, 2,3,3,3-pentafluoropropene (1225ye-E) based on the total weight of the first composition, preferably between 1 and 1000 ppm by weight, preferably between 5 and 500 ppm and in particular between 10 and 250 ppm by weight trans-l, 2,3,3,3-pentafluoropropene (1225ye-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 cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z) based on the total weight of the first composition, preferably between 1 and 1000 ppm by weight, preferably between 5 and 500 ppm and in particular between 10 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 3,3,3-trifluoropropene (1243zf) based on the total weight of the first composition, advantageously between 1 and 5000 ppm by weight, preferably from 5 and 2000 ppm and in particular between 10 and 1500 ppm by weight of 3,3,3-trifluoropropene (1243zf) based on the total weight of the first composition.

According to a particular embodiment, said organic extractant may be one solvent selected from the group consisting hydrohalocarbure, alcohol, ketone, amine, ester, ether, aldehyde, nitrile, carbonate, thioalkyl, amide, heterocycle; or the organic extractant is triethylfluorosilane. Preferably the organic extractant is selected from the group consisting of amino, ether, ester, aldehyde, ketone, alcohol and heterocycle.

De préférence, les hydrohalocarbures sont sélectionnés parmi le groupe consistant en bromofluoromethane, l-bromo-l,2-difluoroethylene, l,l,l-trifluoro-2-bromoethane, 2-chloropropane, bromoethane, iodomethane, 2-chloro-2-methylpropane, 2-bromopropane, chlorobromomethane, 3-bromopropene, 1-bromopropane, iodoethane, 2-bromo-2-methylpropane, l-chloro-3-fluoropropane, 2-chloro-2-methylbutane, 1,2-dichloroethane, 2-iodopropane, dichlorobromomethane, 2-bromobutane, 1,2-dichloropropane, trichloroacetaldehyde, l-chloro-4-fluorobutane, l-bromo-3-fluoropropane, 1-bromobutane, 1-iodopropane, cis-l,3-dichloropropene, bromotrichloromethane, l-bromo-2-chloroethane, 2-bromo-2-methylbutane, trans-l,3-dichloropropene, 1,1,2-trichloroethane, 2-bromopentane, 2,3-dichlorobutane, l-bromo-3-methylbutane, l,3-dichloro-trans-2-butene, 1,3-dichloropropane, 1,2-dibromo-l-fluoroethane, 1,2,2-trichloropropane, 2,3-dichloro-2-methylbutane, 1-bromopentane, l,2-dichloro-2-butene, 1-iodobutane, 1,2-dibromoethane,

1,1,2-trichloropropane, 1,3-dichlorobutane, 1,2-dibromopropane, 1,2,3-trichloropropene, 1-chloro-3-bromopropane, tribromomethane.

De préférence, les alcools sont sélectionnés parmi le groupe consistant en méthanol, 2,2,2-trifluoroethanol, l,l,l-trifluoro-2-propanol, ethanol, 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, l-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, l-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, 2,3-dimethylbutanol, 2-ethyl-1-butanol, 2-methyl-l-pentanol, 2-propoxyethanol.

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.

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, 2-methoxy-l-propene, diethylether, ethoxy-ethene, dimethoxymethane, methylcyclopropylether, 2-ethoxy-propane, methyl-t-butylether, chloromethoxymethane, diisopropylether, 2-ethoxy-2-methyl-propane, 2-ethoxy-butane, 1-

methoxy-2-methyl-butane, 2,2-dimethoxypropane, l-ethoxy-2-methylpropane, 1,2-dimethoxyethane, diethoxymethane, di-n-propylether, 1-ethoxybutane, 1-methoxy-pentane, l,2-dimethoxypropane„ isopropyl-isobutyl-ether, 1,1-diethoxyethane, trimethoxymethane, 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, 1,1,1-triethoxyethane, l-methoxy-2-acetoxypropane.

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 diéthylcaarbonate.

Preferably the amide is ethanethioamide.

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

Preferably, heterocycles are selected from the group consisting of tetrahydrofuran, dioxane, 1,3-dioxane, 1,3,5-trioxane, N-methylmorpholine, 2-methylpyrazine, n-ethyl-morpholine, 1-methylpiperazine, 1, 2-epoxypropane, piperidine, 3-furfural, 2,6-dimethylmorpholine.

Ledit agent d'extraction organique peut être éthylamine, bromofluoromethane, 1-bromo-l,2-difluoroethylene, acétaldehyde, l,l,l-trifluoro-2-propanone, l,l,l-trifluoro-2-bromoethane, 2,2,2-trifluoroethylmethylether, isopropylamine, methylformate, 2-methoxy-l-propene, diethylether, 1,2-epoxypropane, éthanethiol, ethoxy-ethene, ethylmethylamine, dimethylsulfide, 2-chloropropane, bromoethane, dimethoxymethane, iodomethane, 2-amino-2-methylpropane, methylcyclopropylether, n-propylamine, isopropylmethylamine, ethanedial, 2-chloro-2-methylpropane, 2-propanethiol, 2-ethoxy-propane, methyl-t-butylether, diethylamine, propanone, methylacetate, 4-methoxy-2-methyl-2-butanethiol, 2-bromopropane, chloromethoxymethane, 2-butanamine, n-methylpropylamine, tert-butylthiol, isobutanal, methanol, tetrahydrofurane, 1-propanethiol, chlorobromomethane, isopropylformate, diisopropylether, 3-bromopropene, 1-bromopropane, methylglyoxal, iodoethane, 2-ethoxy-2-methyl-propane, 2-bromo-2-methylpropane, 2,2,2-trifluoroethanol, 1- chloro-3-fluoropropane, l,l,l-trifluoro-2-propanol, 1-butylamine, ethylacetate, ethanol, butanone, n-propylformate, 2-ethoxy-butane, 2-propanol, acetonitrile, tert-butanol, 1-methoxy-2-methyl-butane, 2,2-dimethoxypropane, 2-chloro-2-methylbutane, 1,2-dichloroethane, l-ethoxy-2-methylpropane, diisopropylamine, 2-butanethiol, 1,2-dimethoxyethane, 3-methyl-2-butanamine, diethoxymethane, 2-methyl-l-propanethiol, isopropylacetate, 2-iodopropane, di-n-propylether, 3-pentylamine, n-methylbutylamine, 2-bromobutane, diethylsulfide, 1-ethoxybutane, l-methoxy-2-propanamine, 2-methylbutanal, 2-methoxyethanamine, 2,2-difluoroethanol, 1,2-dichloropropane, propanol, tert-butylacetate, propionitrile, trichloroacetaldehyde, 2-allyloxyethanol, butanethiol, 1-methoxy-pentane, ethylpropionate, 2-butanol, 1,2-dimethoxypropane, isopropyl-isobutyl-ether, l-chloro-4-fluorobutane, l-bromo-3-fluoropropane, dioxane, 1-bromobutane, 3-pentanone, 1,1-diethoxyethane, 2-pentanone, 2-methyl-2-butanol, 1-iodopropane, 2-methoxy-lpropanamine, trimethoxymethane, cis-l,3-dichloropropene, n-pentylamine, 3,3-dimethyl-2-butanone, 1,3-dioxane, piperidine, l-bromo-2-chloroethane, isobutanol, 2-bromo-2-methyl butane, dipropylamine, 2,2,3,3-tetraflouro-l-propanol, 2-ethoxyethanamine, triethylfluorosilane, sec-butylacetate, trans-l,3-dichloropropene, 2,2-dimethyl-l-propanol, n-methyl-1,2-ethanediamine, 2,2-diethoxypropane, 1,3,5-trioxane, pyridine, 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, 1-methoxy2-propanol, 1,2-propanediamine, 2,6-dimethyl-5-heptenal, l-bromo-3-methylbutane, l,3-dichloro-trans-2-butene, 1,3-dichloropropane, l-(dimethylamino)-2-propanol, tetrahydrothiophene, 3-methyl-3-pentanol, 1,2-dibromo-l-fluoroethane, 1,1-diethoxypropane, 1,2,2-trichloropropane, l-chloro-2-methyl-2-propanol, 2-methoxyethanol, 4,4,4-trifluorobutanol, 2-ethylbutylamine, diethylcarbonate, n-butylacetate, 1-pentanethiol, 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, l,2-dichloro-2-butene, 1-iodobutane, hexanal, l-ethoxy-2-propanol, 1,2-dibromoethane, 4-methyl-2-pentanol, 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, 2-methylpyrazine, 2-ethoxy-l-propanol, 1-pentanol, n-ethyl-morpholine, 1-methylpiperazine, 1,3-propanediamine, di-n-butylether, valeronitrile,

(methyleneamino)acetonitrile, 1,2-dibromopropane, 1,2,3-trichloropropene, 2-heptanamine, 2,3-dimethylbutanol, 1-ethoxy-hexane, l-chloro-3-bromopropane, n,n-diethylethylenediamine, 3-furfural, 2,6-dimethylpyridine, 4-methyl-2-hexanone, 1,1,1-triethoxyethane, l-methoxy-2-acetoxypropane, 4-methylpyridine, n,n'-diethyl-l,2-ethanediamine, 2,6-dimethylmorpholine, 2-ethyl-l-butanol, 2-methyl-l-pentanol, methylhexanoate, 2-propoxyethanol, l-propoxy-2-propanol, dimethylethanolamine.

A process for purifying 2,3,3,3-tetrafluoro-l-propene (1234yf) from a first composition comprising 2,3,3,3-tetrafluoro-l-propene, 1,1,1,2 , 2-pentafluoropropane (245cb) and trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-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 and trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E); and ii) a stream comprising 2,3,3,3-tetrafluoro-l-propene (1234yf) and 1,1,1,2,2-pentafluoropropane (245cb),

c) recovering and separating said third composition to form a stream comprising said organic extractant and a stream comprising trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E); preferably the stream comprising said organic extractant is recycled to step a).

Method according to the preceding claim characterized in that it also comprises a step of recovering said stream ii) comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2-pentafluoropropane ( 245cb) obtained in stage b) and distillation thereof to form a stream a comprising 2,3,3,3-tetrafluoro-l-propene and a stream B comprising 1,1,1,2,2 -pentafluoropropane (245cb).

A method according to any preceding claim characterized in that said first composition further comprises at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2 -tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3 , 3,3-trifluoropropene (1243zf).

Method according to the preceding claim characterized in that said at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane ( 115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf ) are also contained in said second and third compositions; step c) of this process is the recovery and separation of said third composition to form firstly a stream comprising said organic extractant and also a stream comprising the trans-3,3, 3-tetrafluoro-l-propene (1234ze-E) and said at least one compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a ), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (1225ye-E), cis-1,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3 -trifluoropropene (1243zf); preferably the stream comprising said organic extractant is recycled to step a).

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

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 is the activity coefficient 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-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.

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 1,1,1,2,2-pentafluoropropane (245cb) in said organic extractant at infinite dilution,

IP is the saturation vapor pressure of 1,1,1,2,2-pentafluoropropane (245cb), 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,

P2 represents the saturation vapor pressure of the 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.

A method according to any preceding claim characterized in that said organic extractant has a C2 absorbency, 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 said at least one of the compounds consisting of trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E) in said agent organic extraction at infinite dilution, preferably y2, s represents the coefficient of activity of said at least one of the compounds consisting of 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.

A method according to any preceding claim characterized in that said organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, propanone, methyl acetate, butanone, diethoxymethane, isopropylacetate, 3- pentylamine, 2-methoxyethanamine, tert-butyl acetate, dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butyl acetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1, 2- propanediamine, n-butylacetate, 2-methoxy-l-propanol, hexanal. Preferably, said organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tert-butyl acetate, dioxane, 1,1- diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec- Butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, n- Butylacetate, 2-methoxy-l-propanol, hexanal.

10. A method according to any preceding claim characterized in that the current ii) comprising 2,3,3,3-tetrafluoro-l-propene and 1,1,1,2,2- pentafluoropropane (245cb) formed in step b) is recovered and is free of trans 1,3,3,3-tetrafluoro-l-propene (1234ze-E).

11. A method according to any preceding claim characterized in that it comprises, prior to step a) the steps of:

i ') implementation of a composition comprising 2,3,3,3-tetrafluoro-l-propene, impurities having a boiling point below the boiling point of 2,3,3,3-tetrafluoro- l-propene, 1,1,1,2,2-pentafluoropropane (245cb) and trans- 1,3,3,3-tetrafluoro-l-propene (1234ze-E), optionally or not at least one of the selected compounds from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-l, 2,3,3,3-pentafluoropropene (E-1225ye), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), and optionally or non-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, 1,1,1,2,2-pentafluoropropane (245cb) and trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E), optionally or not at least one of compounds selected from the group consisting of chloromethane (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-2,3,3,3 -pentafluoropropene (E-1225ye), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), and optionally or non-heavy impurities, recovered at the bottom of distillation column;

iii ') optionally or not, 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, 1,1,1,2,2- pentafluoropropane (245cb) and trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E), optionally or not at least one of compounds selected from the group consisting of in methyl chloride (40), 1,1-difluoroethane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroethane (115), trans-1,2,3,3,3-pentafluoropropene (1225ye-E ), cis-l, 2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf), and 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).

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 catalytic 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, 1,1,1,2,2- pentafluoropropane (245cb), trans-l, 3,3,3-tetrafluoro- l-propene (1234ze-E), and optionally or not at least one of compounds selected from the group

consistant en chlorométhane (40), 1,1-difluoroéthane (152a), 1,1,1,2-tetrafluoroethane (134a), chloropentafluoroéthane (115), trans-l,2,3,3,3-pentafluoropropene (1225ye-E), cis-l,2,3,3,3-pentafluoropropene (1225ye-Z), 3,3,3-trifluoropropene (1243zf) ;

C) implementation of the purification process of the 2,3,3,3-tetrafluoro-l-propene according to any one of claims 1 to 11 from the stream recovered in step B).

13. A composition comprising 2,3,3,3-tetrafluoropropene, 1,1,1,2,2-pentafluoropropane (245cb), 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 1.60, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2 ) wherein yi, s is 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 is the activity coefficient of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution, P2 represents the saturation vapor pressure of the trans-l, 3,3,3-tetrafluoro-l- propene (1234ze-E);

and said organic extractant having a separation factor If two greater than or equal to 1.60, said separation factor is calculated by the formula Si, 2 = (yi, s * PI) / (y2, s * P2 ) wherein yi, s is the activity coefficient of 1,1,1,2,2- pentafluoropropane (245cb) in said organic extractant at infinite dilution,

IP is the saturation vapor pressure of 1,1,1,2,2-pentafluoropropane (245cb), 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, P2 represents the saturation vapor pressure of the trans-l, 3,3,3-tetrafluoro-l-propene (1234ze-E);

preferably said organic extractant has a C2 absorbency, s greater than or equal to 0.60, said absorptive capacity is calculated by the formula C2, s = l / (Y2, s) wherein y2, s is the activity coefficient of trans-1,3,3,3-tetrafluoro-l-propene (1234ze-E) in said organic extractant at infinite dilution.

14. Composition according to the preceding claim characterized in that the organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, propanone, methyl acetate, butanone, diethoxymethane, isopropylacetate, 3-pentylamine , 2-methoxyethanamine, tert-butyl acetate, dioxane, 1,1-diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec-butyl acetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1.2 - propanediamine, n-butyl acetate, 2-methoxy-l-propanol, hexanal. Preferably, said organic extractant is selected from the group consisting of ethylamine, isopropylamine, diethyl ether, n-propylamine, diethylamine, diethoxymethane, isopropylacetate, 3-pentylamine, 2-methoxyethanamine, tert-butyl acetate, dioxane, 1,1- diethoxyethane, trimethoxymethane, n-pentylamine, 1,3-dioxane, sec- Butylacetate, 1,2-diaminoethane, l-methoxy-2-propanol, 1,2-propanediamine, n- Butylacetate, 2-methoxy-l-propanol, hexanal.

15. The composition of claim 13 or 14 characterized in that it is devoid of HF.