Purification of a composition comprising at least one (hydro)halogenated olefin

Abstract

The invention relates to a method for removing a polymerization inhibitor from a CT1 composition to be treated, said CT1 composition comprising at least one (hydro)halogenated olefin and at least one polymerization inhibitor of said at least one (hydro)halogenated olefin, said method comprising a step in which said CT1 composition is passed through a column packed with an activated carbon bed, and / or a method for purifying a CT2 composition comprising trifluoroethylene and at least one compound to be removed, at least partially, selected from a (hydro)chlorofluorinated olefin, a (hydro)chlorofluorinated alkane, said method comprising a step in which said CT2 composition is passed through a column packed with an activated carbon bed, as well as corresponding compositions. Figure for the abstract: no figure

Description

Title of the invention: Purification of a composition comprising at least one (hydro)halogenated olefin technical field

[0001] The invention relates to purification processes for compositions comprising at least one (hydro)halogenated olefin. More specifically, the invention relates to purification processes allowing, according to a first aspect, the treatment of a composition comprising a (hydro)halogenated olefin and a polymerization inhibitor by removing the polymerization inhibitor, and, in a complementary or alternative manner, allowing, according to a second aspect, the treatment of a composition comprising trifluoroethylene and one or more impurities of the (hydro)chlorofluorinated olefin or (hydro)chlorofluorinated alkane type.

[0002] The invention also relates to compositions that can be obtained from these processes. In particular, the invention relates to trifluoroethylene-based compositions substantially devoid of said polymerization inhibitor and / or trifluoroethylene-based compositions in which one or more (hydro)chlorofluorinated olefin and / or (hydro)chlorofluorinated alkane impurities have been at least partially removed. Previous art

[0003] Organic substances used as polymerization inhibitors for (hydro)halogenated olefins, such as vinyl fluoride, tetrafluoroethylene, and trifluoroethylene, are varied and well known. Several methods for removing these polymerization inhibitors have been disclosed in the prior art.

[0004] Document WO2013090941 discloses a process for removing limonene from a d-limonene stabilized vinyl fluoride composition. The process involves passing the gaseous composition to be treated through a tube containing silica gel.

[0005] US patent 8,247,626 indicates that terpenes, including α-pinene, γ-pinene, α-terpinene, γ-terpinene, diterpene, terpinolene, isoterpinolene, and camphene, can be used as a polymerization inhibitor of tetrafluoroethylene. The patent specifically discloses a process for substantially removing α-pinene from a gaseous composition of tetrafluoroethylene stabilized with 130 ppm α-pinene. The process involves passing the gaseous composition to be treated through a tube containing a silica gel comprising a metal salt from groups 8 to 10 of the periodic table of elements.

[0006] Document JPH03223219 discloses tetrafluoroethylene compositions stabilized with limonene, α-pinene, or p-cymene as a polymerization inhibitor. In particular, the document discloses a process for substantially removing the polymerization inhibitor from a stabilized tetrafluoroethylene gas composition by adsorption onto a zeolite that has been modified by prior contact with a gas such as Freon 113 (trichlorotrifluoroethane), Freon 11 (trichlorofluoromethane), Freon 114 (cryofluorane), or Freon 22 (chlorodifluoromethane).

[0007] It is also known, as mentioned for example in paragraph

[0009] of EP3023404, to stabilize trifluoroethylene with limonene. This document does not specify any method for removing the limonene.

[0008] The prior art methods described above for removing a polymerization inhibitor from a (hydro)halogenated olefin stabilized with said inhibitor are either of limited effectiveness (silica gel, hydrophilic) or complicated to implement (modified or additive adsorbents). Therefore, there is a need to provide new methods, advantageously more effective and / or simpler to implement, for removing the polymerization inhibitor from a stabilized composition based on a (hydro)halogenated olefin.

[0009] It is also known, for example in EP2819979 and EP2993213, that one method of manufacturing trifluoroethylene is the hydrogenolysis of chlorotrifluoroethylene. Document EP2819979 discloses a trifluoroethylene obtained by this method and 98.96% pure by mass. Such a trifluoroethylene can be used in a process for manufacturing a copolymer comprising, or essentially consisting of, repeating units resulting from the polymerization of vinylidene fluoride and trifluoroethylene. Document EP2993213 also presents a trifluoroethylene obtained by this method and 99.5% pure by mass. It also discloses the impurities present.Among the impurities, we can mention (hydro)chlorofluorinated olefins, such as chlorotrifluoroethylene, l-chloro-2,2-difluoroethylene (HCFO-1122), and E- or Zl-chloro-l,2-difluoroethylene (HCFO-1122a); hydrofluorinated olefins, such as vinylidene fluoride (1,1-difluoroethylene), and E- or Zl,2-difluoroethylene (HFO-1132); hydrofluoroalkanes, such as l-chloro-l,l-difluoroethane (HCFC-142b), l-chloro-l,l,2-trifluoroethane (HCFC-133b), 1-chloro-1,2,2-trifluoroethane (HCFC-133), 2-chloro-l,l-difluoroethane (HCFC-142), 1,2-dichloro-l,l,2-trifluoroethane (HCFC-123a), l,l,2-trichloro-l,2,2-trifluoroethane (CFC-113); or hydrofluoroalkanes, such as 1,1-difluoroethane (HFC-152a), or 1,1,2-trifluoroethane (HFC-143).

[0010] It is finally known from EP2993213 that another method of manufacturing trifluoroethylene is the thermal decomposition of a mixture of chlorodifluoromethane (HCFC-22) and chlorofluoromethane (HCFC-31). The document discloses that a 99.5% pure trifluoroethylene by mass is obtained and comprises the following impurities: (hydro)fluorinated olefins, such as fluoroethylene (HFO-1141), El,2-difluoroethylene (E-HFO-1132), tetrafluoroethylene, 3,3-difluoropropene (HFO-1252zf); a hydrochlorofluorinated alkane, such as chlorodifluoromethane (HCFC-22); and hydrofluorinated alkanes, such as difluoromethane (HFC-32), pentafluoroethane (HFC-125), trifluoromethane (HFC-23), fluoromethane (HFC-41), and 1,1,1-trifluoroethane (HFC-143a).

[0011] There is currently a need to supply trifluoroethylene, in particular trifluoroethylene obtained by hydrogenolysis of chlorotrifluoroethylene or by thermal decomposition of a mixture of chlorodifluoromethane and chlorofluoromethane, free from chlorinated impurities and / or of higher purity, for example for the manufacture of copolymers comprising, or essentially consisting of, repeating units resulting from the polymerization of vinylidene fluoride and trifluoroethylene, or for any other application where high purity is required. Objectives of the invention

[0012] The invention overcomes at least some of the drawbacks of the prior art.

[0013] An objective of the invention is to provide a new process for treating compositions comprising at least one (hydro)halogenated olefin.

[0014] Another objective, at least according to certain embodiments, is to propose a simple process to implement.

[0015] Another objective, at least according to certain embodiments, is to propose an efficient process to be implemented.

[0016] Another objective, at least according to certain embodiments, is to propose an efficient process to be implemented.

[0017] Another objective, at least according to some embodiments, is to propose a process for eliminating a polymerization inhibitor from a composition comprising a (hydro)halogenated olefin stabilized with this polymerization inhibitor.

[0018] Another objective, at least according to some embodiments, is to propose a process for removing a polymerization inhibitor from a composition comprising trifluoroethylene stabilized with this polymerization inhibitor.

[0019] Another objective, at least according to some embodiments, is to propose a process allowing at least partial removal of one or more (hydro)chlorofluorinated olefin or (hydro)chlorofluorinated alkane type impurities from a trifluoroethylene-based composition.

[0020] Another objective, at least according to some embodiments, is to propose a process allowing at least partial removal of chlorotrifluoroethylene from a trifluoroethylene-based composition initially containing it.

[0021] Another objective of the invention, at least according to certain embodiments, is to provide a trifluoroethylene-based composition essentially free of polymerization inhibitor.

[0022] Another objective of the invention, at least according to certain embodiments, is to provide a purer trifluoroethylene-based composition, that is to say, one in which one or more impurities of the (hydro)chlorofluorinated olefin or (hydro)chlorofluorinated alkane type have been at least partially removed. Summary of the invention

[0023] According to a first aspect, the invention relates to a method for removing a polymerization inhibitor from a Cn composition to be treated. The CTi composition comprises at least one (hydro)halogenated olefin and at least one polymerization inhibitor of said at least one (hydro)halogenated olefin. The method includes a step in which said CTi composition is passed through a column packed with a bed of activated carbon to obtain a Cri composition. The Cri composition comprises said at least one (hydro)halogenated olefin and is essentially free of said at least one polymerization inhibitor.

[0024] According to certain embodiments, said at least one (hydro)halogenated olefin has the formula (I):

[0025] [Chem.l] CXtX2=CXsX4 (I)

[0026] in which Xi is chosen from F and Cl, and where X2, X3 and X4 are independently chosen from: H, F and Cl.

[0027] According to certain embodiments, said at least one hydro(halogenated) olefin is selected from vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, 1,1-chlorofluoroethylene, and mixtures thereof.

[0028] According to some embodiments, the CTi composition comprises at least 90.0%, and preferably at least 95.0% by weight of trifluoroethylene, relative to the total weight of the composition.

[0029] According to certain embodiments, said at least one polymerization inhibitor is selected from monoterpenes, such as limonene, phellandrene, pinene, camphene, myrcene, alpha-terpinene, gamma-terpinene; monoterpenoids, such as citronellol, terpineol and borneol; sesquiterpenes; sesquiterpenoids, Diterpenes and diterpenoids. At least one polymerization inhibitor of this type may be a limonene.

[0030] According to some embodiments, the composition CR[ comprises less than 20 ppm, preferably less than 10 ppm, and extremely preferably less than 5 ppm, in moles of said at least one polymerization inhibitor relative to the number of moles of said at least one (hydro)halogenated olefin in the composition Cri.

[0031] According to some embodiments, said composition Cn comprises more than 30 ppm by mole of said at least one polymerization inhibitor relative to the number of moles of said at least one (hydro)halogenated olefin in the composition CTi.

[0032] The invention relates according to a second aspect to a process for purifying a CT2 composition comprising trifluoroethylene and at least one compound to be removed, at least in part, selected from a (hydro)chlorofluorinated olefin, a (hydro)chlorofluorinated alkane, or a mixture thereof, the trifluoroethylene representing at least 90.0% by weight, and preferably at least 95.0% by weight relative to the total weight of composition CT2, and having an XCF proportion in the at least one compound to be removed, expressed in moles of the at least one compound to be removed relative to the number of moles of trifluoroethylene in composition CT2.The process includes a step where said composition CT2 is passed through a column filled with a bed of activated carbon, in order to obtain a composition CR2, said composition CR2 comprising trifluoroethylene and at least one compound to be removed, the proportion YCF in the at least one compound to be removed, expressed in moles of the at least one compound to be removed relative to the number of moles of trifluoroethylene in composition CT2 being less than or equal to XCF / 2, preferably less than or equal to XCF / 3, and more preferably less than or equal to XCF / 5.

[0033] According to some embodiments, at least one compound to be eliminated includes chlorotrifluoroethylene.

[0034] According to some embodiments, at least one compound to be eliminated is chlorotrifluoroethylene.

[0035] According to certain embodiments of a process according to the first aspect and / or of a process according to the second aspect, the step in which the composition to be treated is passed through the column filled with the activated carbon bed, is carried out with said composition to be treated being in gaseous form.

[0036] According to certain embodiments, the step in which said composition to be treated is passed through the column filled with the activated carbon bed is carried out so that the temperature in the column does not exceed 45°C, preferably does not exceed 40°C, preferably still does not exceed 35°C, and even more preferably does not exceed 30°C.

[0037] According to certain embodiments, the step in which said composition to be treated is passed through the column filled with the activated carbon bed is implemented in such a way that the empty drum velocity of said composition to be treated in the column is from 1 m / min to 40 m / min, preferably from 1.5 m / min to 35 m / min, and more preferably from 2 m / min to 30 m / min.

[0038] According to some embodiments, the step in which said composition to be treated is passed through the column filled with the activated carbon bed is implemented in such a way that the residence time of said composition to be treated in the column is at least 2 s.

[0039] According to certain embodiments, said activated carbon of the activated carbon bed has an iodine value greater than or equal to 800 mg / g, and preferably greater than or equal to 850 mg / g, as measured according to ASTM D4607-14(2021).

[0040] According to certain embodiments, said activated carbon of the activated carbon bed has an iodine value less than or equal to 1200 mg / g, preferably less than or equal to 1100 mg / g, preferably still less than or equal to 1050 mg / g, and more preferably less than or equal to 1025 mg / g, as measured according to ASTM D4607-14(2021).

[0041] The invention also relates to a composition comprising at least 98.0%, preferably at least 99.0%, and more preferably at least 99.5% by weight of trifluoroethylene relative to the total weight of the composition, and from 0.01 ppm to 50 ppm by mole of chlorofluorinated or hydrochlorofluorinated compound(s) relative to the number of moles of trifluoroethylene in the composition.

[0042] According to some embodiments, said composition comprises chlorotrifluoroethylene, and at least one other chlorofluorinated or hydrochlorofluorinated compound.

[0043] According to some embodiments, said composition comprises chlorotrifluoroethylene as the only chlorofluorinated or hydrochlorofluorinated compound of the composition.

[0044] According to certain embodiments, the composition comprises from 0.01 ppm to 10 ppm, and preferably from 0.01 ppm to 5 ppm by moles, of a trifluoroethylene polymerization inhibitor, relative to the number of moles of trifluoroethylene in the composition. In particular embodiments, this inhibitor is a limonene.

[0045] According to some embodiments, the composition comprises from 1 ppm to 5000 ppm by mole of vinylidene fluoride, relative to the number of moles of trifluoroethylene in the composition. In particular, the composition may comprise from 250 ppm to 2500 ppm by mole of vinylidene fluoride, relative to the number of moles of trifluoroethylene in the composition.

[0046] According to some embodiments, the composition comprises vinylidene fluoride. The total weight of trifluoroethylene and vinylidene fluoride represents at least 99.90%, preferably at least 99.95%, and more preferably at least 99.98% by weight, relative to the weight of the composition.

[0047] The invention also relates to a composition comprising at least 98.0%, and preferably at least 99.5%, by weight of trifluoroethylene, relative to the total weight of the composition, and from 0.01 ppm to 10 ppm, preferably from 0.01 ppm to 5 ppm by mole of a polymerization inhibitor relative to the number of moles of trifluoroethylene in the composition. According to particular embodiments, this inhibitor is limonene.

[0048] The invention also relates to the use of one of these compositions as a pickling or etching gas.

[0049] The invention ultimately relates to the use of one of these compositions for the polymerization of a polymer comprising, or being essentially made up of, or being made up of, repeating units resulting from the polymerization of vinylidene fluoride and trifluoroethylene. Detailed description of the invention Composition to be treated

[0050] The composition to be treated CT comprises at least one (hydro)halogenated olefin and at least one chemical species to be removed, at least partially, from the composition by means of the process according to the invention. "(Hydro)halogenated olefin" means a "halogenated olefin" or a "hydrohalogenated olefin," that is, a hydrocarbon having at least one carbon-carbon covalent double bond, of which only some of the hydrogen atoms have been substituted by a halogen atom (hydrohalogenated olefin) or of which all the hydrogen atoms have been substituted by a halogen atom (halogenated olefin, also called perhalogenated olefin). "(Hydro)fluorinated olefin" means a hydrohalogenated olefin or a halogenated olefin comprising only fluorine as the halogen atom. The term "(hydro)chlorofluorinated olefin" means a hydrohalogenated olefin or a halogenated olefin comprising only fluorine and chlorine as halogen atoms.

[0051] According to a first aspect of the invention, the composition to be treated CT can be a composition Cn comprising at least one (hydro)halogenated olefin and at least one polymerization inhibitor of said at least one (hydro)halogenated olefin.

[0052] The term “polymerization inhibitor” means a chemical compound used to prevent the spontaneous polymerization of the monomer to which it is added.

[0053] According to some embodiments, said at least one inhibitor is a chemical compound comprising at least one multi-bonded carbon atom such as is found in compounds containing ethylenic or acetylenic bonds. Examples of compounds containing an ethylenic bond include hydrocarbons Ethylene compounds such as hexenes and octenes, terpenes, terpenoids, vinylcyclohexene, and cyclohexene. Examples of compounds containing an acetylenic bond are 1-pentine, vinylacetylene, and divinylacetylene.

[0054] Advantageously, said at least one inhibitor is a chemical compound comprising one or more multi-bonded carbon atoms and in which there is no hydrogen atom on at least one multi-bonded carbon atom. These compounds are particularly likely to react with atmospheric oxygen.

[0055] According to preferred embodiments, said at least one polymerization inhibitor may be selected from terpenes and terpenoids. Terpenes are a family of compounds with the basic formula (C5H8)n, where "n" is an integer greater than or equal to 1. Terpenoids are derivatives of terpenes containing functional groups. Said at least one polymerization inhibitor may be selected from monoterpenes (n=2), monoterpenoids, sesquiterpenes (n=3), sesquiterpenoids, diterpenes (n=4), diterpenoids, and mixtures thereof. Said at least one polymerization inhibitor may, in particular, be selected from monoterpenes and monoterpenoids.

[0056] According to more preferred embodiments, said at least one polymerization inhibitor is selected from monoterpenes, monoterpenoids, or mixtures thereof. Among the monoterpenes, examples include limonene (d-limonene, 1-limonene, or mixtures thereof, a racemic mixture of the two enantiomers being known as dipentene), phellandrene (α-phellandrene, β-phellandrene, or mixtures thereof), pinene (α-pinene, β-pinene, or mixtures thereof), camphene, myrcene, terpinene (α-terpinene, β-terpinene, γ-terpinene, or mixtures thereof), and isoterpinolene. Examples of monoterpenoids include citronellol, a terpineol (α-terpineol, γ-terpineol, γ-terpineol, terpinene-4-ol, or mixtures thereof), and bomeol. This at least one polymerization inhibitor may include a limonene, such as δ-limonene, β-limonene, or mixtures thereof, whether racemic or not.

[0057] Said at least one polymerization inhibitor is generally used in such quantity that it makes it possible to stabilize said at least one (hydro)halogenated olefin during its storage and thus prevent any polymerization over time.

[0058] Said at least one polymerization inhibitor generally represents at least 30 ppm by mole relative to the total number of moles of said at least one (hydro)olefin of composition CTi. According to certain embodiments, said at least one polymerization inhibitor may represent at least 50 ppm, or at least 100 ppm, or at least 250 ppm, or even at least 500 ppm by mole relative to the total number of moles of said at least one (hydro)halogenated olefin. In embodiments where composition Cn comprises a mixture of polymerization inhibitors and / or a mixture of (hydro)halogenated olefins, the total number of moles of all polymerization inhibitors generally represents at least 30 ppm, or at least 50 ppm, or at least 100 ppm, or at least 250 ppm, or even at least 500 ppm in moles relative to the total number of moles of all (hydro)halogenated olefins in the composition.

[0059] In advantageous embodiments where the Cn composition is in gaseous form, the partial pressure of a polymerization inhibitor in the composition may be equal to at least 50% of its saturated vapor pressure, or at least 75% of its saturated vapor pressure, or at least 85% of its saturated vapor pressure.

[0060] According to certain embodiments, said at least one (hydro)halogenated olefin is chosen from compounds of formula (I):

[0061] [Chem.2] CXtX2=CXsX4 (!)

[0062] in which Xi is chosen from F and Cl, and where X2, X3 and X4 are independently chosen from: H, F and Cl.

[0063] According to preferred embodiments, said at least one (hydro)halogenated olefin may be selected from vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, 1,1-chlorofluoroethylene, and mixtures thereof. In particular, said at least one (hydro)halogenated olefin may be selected from vinyl fluoride, trifluoroethylene, tetrafluoroethylene, and mixtures thereof.

[0064] According to certain embodiments, said at least one (hydro)halogenated olefin represents at least 90.0% by weight, or at least 95.0% by weight, or at least 98.0% by weight, or at least 99.0% by weight, or at least 99.5% by weight, relative to the weight of composition Cn. In embodiments where composition Cn comprises a mixture of (hydro)halogenated olefins, the total weight of all (hydro)halogenated olefins may represent at least 90.0% by weight, or at least 95.0% by weight, or at least 98.0% by weight, or at least 99.0% by weight, or at least 99.5% by weight, relative to the weight of composition CTi.

[0065] According to certain embodiments, the Cn composition to be treated comprises at least 90.0% by weight, and preferably at least 95.0% by weight, of a single (hydro)halogenated olefin of formula (I), relative to the weight of composition CTi. The Cn composition to be treated may comprise at least 90.0% by weight, or at least 95.0% by weight, or at least 98.0% by weight, or at least 99.0% by weight, or at least 99.5% by weight of a single (hydro)halogenated olefin selected from vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, and 1,1-chlorofluoroethylene, relative to the weight of composition Cn-

[0066] In particular, the Cn composition to be treated may comprise at least 90.0% by weight, or at least 95.0% by weight, or at least 98.0% by weight, or at least 99.0% by weight, or at least 99.5% by weight of a single (hydro)halogenated olefin selected from vinyl fluoride, trifluoroethylene, and tetrafluoroethylene, relative to the weight of composition CTi.

[0067] According to particular embodiments, the Cn composition to be treated may comprise at least 90.0% by weight, or at least 95.0% by weight, or at least 98.0% by weight, or at least 99.0% by weight, or at least 99.5% by weight, of trifluoroethylene relative to the weight of the CTi composition. According to these embodiments, the Cn composition may also comprise chlorotrifluoroethylene. This may, for example, be the case when the trifluoroethylene is obtained by a hydrogenolysis process of chlorotrifluoroethylene.

[0068] According to a second, alternative or complementary aspect of the invention, the CT composition to be treated can be a CT2 composition comprising trifluoroethylene and at least one impurity of trifluoroethylene to be removed, at least in part, chosen from (hydro)chlorofluorinated olefins and (hydro)chlorofluorinated alkanes, the trifluoroethylene representing at least 90% by weight relative to the weight of the CT2 composition.

[0069] The term "hydrohalogenated alkane" means a "halogenated alkane" or a "hydrohalogenated alkane," that is, a hydrocarbon with only single covalent carbon-carbon bonds, in which only some of the hydrogen atoms have been substituted by a halogen atom (hydrohalogenated alkane) or in which all the hydrogen atoms have been substituted by a halogen atom (halogenated alkane, also called a perhalogenated alkane). The term "hydrofluorinated alkane" means a hydrohalogenated alkane or a halogenated alkane comprising only fluorine as a halogen atom, that is, what is commonly called a fluorocarbon or a hydrofluorocarbon. The term "hydrochlorofluoroalkane" means a hydrohalogenated alkane or a halogenated alkane comprising only fluorine and chlorine as halogen atoms, that is, what is commonly called a chlorofluorocarbon or a hydrochlorofluorocarbon.

[0070] The CT2 composition to be treated may comprise at least 95% by weight, or even at least 98% by weight, of trifluoroethylene relative to the weight of the CT2 composition.

[0071] Composition CT2 may in particular be a composition that can be obtained by a hydrogenolysis process of chlorotrifluoroethylene for the manufacture of trifluoroethylene or by a thermal decomposition process of a mixture of chlorodifluoromethane and chlorofluoromethane.

[0072] According to preferred embodiments, composition CT2 is a composition that can be obtained by a hydrogenolysis process of chlorotrifluoroethylene. Such a process is described in detail below.

[0073] Said process for producing trifluoroethylene can be implemented in a reactor equipped with a fixed catalytic bed comprising a catalyst. It comprises a step I of reacting chlorotrifluoroethylene with hydrogen in the presence of the catalyst and in the gas phase to produce a product stream comprising trifluoroethylene and optionally chlorotrifluoroethylene.

[0074] According to a preferred embodiment, the process can be implemented continuously.

[0075] According to a preferred embodiment, the hydrogen is in anhydrous form. According In a preferred embodiment, chlorotrifluoroethylene is in anhydrous form. Implementing the processes in the presence of hydrogen and / or anhydrous chlorotrifluoroethylene effectively increases the catalyst lifetime and thus the overall process productivity. The term anhydrous refers to a water content of less than 1000 ppm by mass, advantageously 500 ppm, preferably less than 200 ppm, and in particular less than 100 ppm based on the total weight of the compound.

[0076] Preferably, the catalyst is based on a metal from columns 8 to 10 of the periodic table of elements. In particular, the catalyst is based on a metal selected from the group consisting of Pd, Pt, Rh, and Ru; preferably palladium.

[0077] Preferably, the catalyst is supported. The support is preferably selected from the group consisting of activated carbon, an aluminum-based support, calcium carbonate, and graphite. Preferably, the support is aluminum-based. In particular, the support is alumina. The alumina may be alpha alumina. Preferably, the alumina comprises at least 90% alpha alumina. It has been observed that the conversion of the hydrogenolysis reaction is improved when the alumina is alpha alumina. Thus, the catalyst is more particularly palladium supported on alumina, advantageously palladium supported on an alumina comprising at least 90% alpha alumina, preferably palladium supported on alpha alumina.

[0078] Preferably, palladium represents from 0.01% to 5% by weight based on the total weight of the catalyst, preferably from 0.1% to 2% by weight based on the total weight of the catalyst.

[0079] In particular, said catalyst comprises from 0.01% to 5% by weight of palladium supported on alumina, preferably the alumina comprises at least 90% alpha alumina, more preferably the alumina is an alpha alumina.

[0080] Said catalyst is preferably activated before its use in step a). Preferably, the catalyst activation is carried out at high temperature and in the presence of a reducing agent. According to a particular embodiment, The reducing agent is selected from the group consisting of hydrogen, carbon monoxide, nitrogen monoxide, formaldehyde, Ci-C6 alkanes, and Ci-ClO hydrohalocarbons, or a mixture thereof; preferably hydrogen or a Ci-ClO hydrohalocarbon, or a mixture thereof; in particular, hydrogen, chlorotrifluoroethylene, trifluoroethylene, chlorotrifluoroethane, trifluoroethane, or difluoroethane, or a mixture thereof. Preferably, catalyst activation is carried out at a temperature between 100°C and 400°C, in particular between 150°C and 350°C, in the presence of hydrogen as the reducing agent.

[0081] The process comprises, as mentioned above, a step I of the hydrogenolysis reaction of chlorotrifluoroethylene (CTFE) with hydrogen to produce a stream comprising trifluoroethylene. The hydrogenolysis step is carried out in the presence of a catalyst and in the gas phase. Preferably, the hydrogenolysis step is carried out in the presence of a previously activated catalyst and in the gas phase. The hydrogenolysis step consists of simultaneously introducing hydrogen, CTFE, and optionally an inert gas, such as nitrogen, in the gas phase and in the presence of said catalyst, preferably activated.

[0082] Preferably, said step I) is carried out at a fixed catalytic bed temperature between 50°C and 250°C. Said step a) can be carried out at a fixed catalytic bed temperature between 50°C and 240°C, advantageously between 50°C and 230°C, preferably between 50°C and 220°C, more preferably between 50°C and 210°C, in particular between 50°C and 200°C. The said step I) can also be implemented at a fixed catalytic bed temperature between 60°C and 250°C, advantageously between 70°C and 250°C, preferably between 80°C and 250°C, more preferably between 90°C and 250°C, in particular between 100°C and 250°C, more particularly between 120°C and 250°C.Said step I) can also be implemented at a fixed catalytic bed temperature between 60°C and 240°C, advantageously between 70°C and 230°C, preferably between 80°C and 220°C, more preferably between 90°C and 210°C, in particular between 100°C and 200°C, more particularly between 100°C and 180°C, preferably between 100°C and 160°C, particularly preferably between 120°C and 160°C.

[0083] The H2 / CTFE molar ratio is between 0.5 / 1 and 2 / 1 and preferably between 1 / 1 and 1.2 / 1. If an inert gas such as nitrogen is present in step I), the nitrogen / H2 molar ratio is between 0 / 1 and 2 / 1 and preferably between 0 / 1 and 1 / 1.

[0084] Step I) is preferably carried out at a pressure of 0.05 MPa to 1.1 MPa, more preferably from 0.05 MPa to 0.5 MPa, in particular at atmospheric pressure.

[0085] The contact time calculated as the ratio between the volume, in litres, of catalyst and the total flow rate of the gas mixture, in normal litres per second, at the inlet of the reactor, is between 1 and 60 seconds, preferably between 5 and 45 seconds, in particular between 10 and 30 seconds, more particularly between 15 and 25 seconds.

[0086] The hydrogenolysis step of the process results in the production of a product stream comprising trifluoroethylene. This product stream may also comprise unreacted hydrogen and unreacted chlorotrifluoroethylene. The product stream may also comprise HCl or HF or a mixture of both.

[0087] The stream from step I) can be treated to recover a gaseous mixture M comprising one or more fluorinated compounds A selected from the group consisting of trifluoroethylene and optionally chlorotrifluoroethylene; and one or more additional compounds B selected from the group consisting of hydrogen, nitrogen, argon and helium.

[0088] A processing step II) may include the steps of: i. Removal of HF and / or HCl from said product stream obtained in step I) to form a gaseous mixture; ii. Drying of the gas mixture from step i) to form said gas mixture M. iii. Treatment of the dried gas mixture in step ii) to remove hydrogen and optionally inert gases; iv. Distillation of the mixture from step iii).

[0089] The product stream from step I) is recovered from the reactor outlet in gaseous form. Preferably, at the outlet of the hydrogenolysis reactor, the product stream is first treated to remove HCl and HF. The product stream is passed through water in a scrubbing column and then through a wash with a dilute base such as NaOH or KOH. The remaining gaseous mixture, consisting of the unconverted reactants (H2 and CTFE), the dilution nitrogen (if present), trifluoroethylene, and the additional compounds mentioned above, is directed to a dryer to remove traces of wash water. Drying can be carried out using products such as sodium or magnesium calcium sulfate, calcium chloride, potassium carbonate, silica gel, or zeolites. In one embodiment, a molecular sieve (zeolite) such as siliporite is used for drying.

[0090] The dried gaseous mixture M can be subjected to a step of separating hydrogen and inerts from the other products present in the gaseous mixture by absorption / desorption in the presence of an alcohol comprising 1 to 4 atoms of Carbon and preferably ethanol, at atmospheric pressure and below ambient temperature, preferably below 10°C and even more preferably at -25°C, for absorption. In one embodiment, the absorption of organics is carried out in a countercurrent column with ethanol cooled to -25°C. The ethanol flow rate is adjusted according to the flow rate of organics to be absorbed. Hydrogen and inert gases, insoluble in ethanol at this temperature, are removed at the top of the absorption column. The organics can then be recovered by heating the ethanol to its boiling point (desorption) and subsequently distilled. Alternatively, step iii) can be carried out by a membrane separation process.

[0091] According to step iv), the organics thus obtained are distilled to form and recover a DI stream comprising trifluoroethylene and a D2 stream comprising chlorotrifluoroethylene.

[0092] According to a preferred embodiment, distillation step iv) is carried out at a pressure below 3 bara, preferably at a pressure between 0.5 and 3 bara, and in particular at a pressure between 0.9 and 2 bara. Carrying out distillation at a pressure below 3 bara makes the process safer given the explosive nature of trifluoroethylene above 3 bara. Preferably, distillation step iv) is carried out in a distillation column comprising a structured packing. This structured packing may be made of a metallic material. The DI stream is preferably recovered at the top of the distillation column. Before being recovered, the DI stream may optionally be partially condensed at the top of the distillation column. When partial condensation is carried out, the DI stream is heated to a temperature of -50°C to -70°C. The temperature is adjusted according to the applied pressure.Partial condensation improves distillation efficiency by limiting the content of additional compounds in the stream Dl.

[0093] According to certain embodiments, said at least one compound to be eliminated is the entirety of the (hydro)chlorofluorinated olefin(s) and the (hydro)chlorofluorinated alkane(s) present in composition CT2. The proportion of the total (hydro)chlorofluorinated olefin(s) and the (hydro)chlorofluorinated alkane(s) present in composition CT2 is denoted XCF. It is expressed as the number of moles in parts per million of the total (hydro)chlorofluorinated olefin(s) and the (hydro)chlorofluorinated alkane(s) present in composition CT2, relative to the number of moles of trifluoroethylene in composition CT2. The proportion XCF may be greater than or equal to 95 ppm, or greater than or equal to 250 ppm, or greater than or equal to 500 ppm, or greater than or equal to 1000 ppm. The XCF proportion is generally less than or equal to 50000 ppm, or less than or equal to 20000 ppm.

[0094] Among the (hydro)chlorofluorinated olefins that may be present as impurities in trifluoroethylene are: chlorotrifluoroethylene, l-chloro-2,2-difluoroethylene (HCFO-1122), and E- or Zl-chloro-l,2-difluoroethylene (HCFO-1122a).

[0095] Among the (hydro)chlorofluorinated alkanes that may be present as impurities in trifluoroethylene are: l-chloro-l,l-difluoroethane (HCFC-142b), l-chloro-l,l,2-trifluoroethane (HCFC-133b), l-chloro-l,2,2-trifluoroethane (HCFC-133), 2-chloro-l,l-difluoroethane (HCFC-142), 1,2-dichloro-1,1,2-trifluoroethane (HCFC-123a), l,l,2-trichloro-l,2,2-trifluoroethane (CFC-113), chlorodifluoromethane (HCFC-22) and chlorofluoromethane (HCFC-31).

[0096] According to certain embodiments, said at least one compound to be eliminated is the chlorotrifluoroethylene present in composition CT2. The proportion of chlorotrifluoroethylene present in composition CT2 is denoted XCTfe-. It is expressed as the number of moles in parts per million of chlorotrifluoroethylene in composition CT2, relative to the number of moles of trifluoroethylene in composition CT2. The proportion XCTfe may be greater than or equal to 95 ppm in moles of chlorotrifluoroethylene relative to the number of moles of trifluoroethylene in said composition CT2. Chlorotrifluoroethylene may in particular represent from 95 ppm to 250 ppm, or from 250 ppm to 500 ppm, or from 500 ppm to 1000 ppm, or from 1000 ppm to 2500 ppm, or from 2500 ppm to 5000 ppm, or from 5000 ppm to 10000 ppm, or from 10000 ppm to 20000 ppm, or from 20000 ppm to 50000 ppm, in moles relative to the number of moles of trifluoroethylene in said composition CT2.

[0097] The CT2 composition to be treated may comprise at least 95.0% by weight of trifluoroethylene. It may also comprise from 250 ppm to 500 ppm, or from 500 ppm to 1000 ppm, or from 1000 ppm to 2500 ppm, or from 2500 ppm to 5000 ppm, or from 5000 ppm to 10000 ppm, or from 10000 ppm to 20000 ppm, in moles of chlorotrifluoroethylene relative to the number of moles of trifluoroethylene in said CT2 composition.

[0098] The CT2 composition to be treated may comprise at least 98.0% by weight of trifluoroethylene. It may also comprise from 95 ppm to 250 ppm, or from 250 ppm to 500 ppm, or from 500 ppm to 1000 ppm, or from 1000 ppm to 2500 ppm, or from 2500 ppm to 5000 ppm, or from 5000 ppm to 10000 ppm, in moles of chlorotrifluoroethylene relative to the number of moles of trifluoroethylene in said CT2 composition.

[0099] The CT2 composition to be treated may comprise at least 98.0% by weight of trifluoroethylene. It may also comprise from 95 ppm to 250 ppm, or from 250 ppm to 500 ppm, or from 500 ppm to 1000 ppm, or from 1000 ppm to 2500 ppm, or from 2500 ppm at 5000 ppm, or from 5000 ppm to 10000 ppm, in moles of chlorotrifluoroethylene relative to the number of moles of trifluoroethylene in said composition CT2.

[0100] Composition CT2 may also include other impurities of the (hydro)fluorinated olefin or (hydro)fluorinated alkane type.

[0101] Composition CT2 may include vinylidene fluoride. The proportion of vinylidene fluoride present in composition CT2 is denoted XVdf-It is expressed as the number of moles in parts per million of vinylidene fluoride in composition CT2, relative to the number of moles of trifluoroethylene in composition CT2.

[0102] Composition CT2 may also include 1,1-difluoroethane (HFC-152a), 1,1,2-trifluoroethane (HFC-143), or a mixture thereof.

[0103] Composition CT2 may or may not include a polymerization inhibitor such as those mentioned above and in the proportions described above.

[0104] According to a third aspect of the invention, the composition to be treated may be a CTi-2 composition comprising trifluoroethylene, at least one impurity of trifluoroethylene to be removed, at least partially, selected from (hydro)chlorofluoro olefins and (hydro)chlorofluoro alkanes, and at least one trifluoroethylene polymerization inhibitor. The trifluoroethylene represents at least 90% by weight relative to the weight of the CTi-2 composition. The various embodiments for the CTb2 composition may be obtained by combining embodiments developed for the CTi composition and embodiments developed for the CT2 composition. Processing method

[0105] The treatment process according to the invention includes a step where the CT composition to be treated is passed through a column filled with a bed of activated carbon, in order to obtain a treated CR composition.

[0106] Activated carbon is a material consisting essentially of carbonaceous matter with a porous structure. The carbonaceous matter may be derived from bamboo, coconut shells, peat, wood, lignite, coal, or petroleum pitch. In certain embodiments, the carbonaceous matter of the activated carbon may be derived from bituminous coal or anthracite coal. The carbonaceous matter of the activated carbon may, in particular, be derived from bituminous coal.

[0107] Activated carbon can be in powder, granular, or granule form. Preferably, the activated carbon used in the column is in granular form. Grain sizes generally range from 0.2 mm to 5 mm.

[0108] The activated carbon may have been activated chemically or physically. According to particular embodiments, the activated carbon has been physically activated under an inert atmosphere using oxidizing agents such as steam.

[0109] Preferably, the activated carbon in the activated carbon bed has an iodine value greater than or equal to 800 mg / g as measured according to ASTM D4607-14(2021). The iodine value is an indicator of the microporosity of the activated carbon. A sufficiently high value of this value ensures a sufficiently high adsorption capacity for the species to be removed. The activated carbon in the activated carbon bed advantageously has an iodine value greater than or equal to 850 mg / g. In certain embodiments, the activated carbon in the activated carbon bed may have an iodine value greater than or equal to 850 mg / g.

[0110] Preferably, the activated carbon in the activated carbon bed has an iodine value less than or equal to 1200 mg / g as measured according to ASTM D4607-14(2021). These iodine value values ​​are particularly suitable in embodiments where the activated carbon is used to treat a CT2 type composition. The activated carbon in the activated carbon bed preferably has an iodine value less than or equal to 1100 mg / g, preferably less than or equal to 1050 mg / g, and even more preferably less than or equal to 1025 mg / g, as measured according to ASTM D4607-14(2021).

[0111] In some embodiments, the activated carbon in the activated carbon bed has a methylene blue index greater than or equal to 10 mg / g. The methylene blue index is an indicator of the macroporosity of the activated carbon. In some embodiments, the activated carbon in the activated carbon bed has a methylene blue index greater than or equal to 25 mg / g, or greater than or equal to 50 mg / g, or greater than or equal to 100 mg / g. In some embodiments, the activated carbon in the activated carbon bed has a methylene blue index less than or equal to 400 mg / g, or less than or equal to 300 mg / g.

[0112] The step in which the CT composition to be treated is passed through the column filled with the activated carbon bed is carried out in such a way that the temperature in the column does not preferably exceed 45°C, preferably still does not exceed 40°C, preferably still does not exceed 35°C, and even more preferably does not exceed 30°C. Indeed, when at least one (hydro)halogenated olefin of the CT composition is not or is no longer stabilized by a polymerization inhibitor, it becomes capable of polymerizing. A sufficiently low temperature in the column prevents any risk of polymerization and column clogging.

[0113] According to some embodiments, the column includes means for measuring temperature, in particular sensors, in order to verify that the temperature within it does not exceed one of the temperatures mentioned above.

[0114] According to some embodiments, the column includes temperature control means, for example a water cooler, in order to control the temperature within it.

[0115] According to preferred embodiments, the empty barrel velocity of the composition to be treated in the column is from 1 m / min to 40 m / min. This corresponds to the velocity of the flow of the composition to be treated in the empty column, without activated carbon. Too low an empty barrel velocity can lead to poor distribution of the flow of the composition to be treated in the column and / or clogging due to the polymerization of said at least one (hydro)halogenated olefin. The empty barrel velocity of the composition to be treated in the column is preferably greater than or equal to 1.5 m / min, and more preferably greater than or equal to 2 m / min. Too high an empty barrel velocity can lead to a decrease in the adsorption efficiency of the activated carbon and / or erosion of the activated carbon bed and / or cavitation phenomena.The empty drum velocity of the composition to be treated in the column is preferably less than or equal to 35 m / min, and more preferably less than or equal to 30 m / min. The empty drum velocity of the composition to be treated in the column may in particular be from 1.0 m / min to 1.5 m / min, or from 1.5 m / min to 2.5 m / min, or from 2.5 m / min to 5 m / min, or from 5 m / min to 10 m / min, or from 10 m / min to 15 m / min, or from 15 m / min to 20 m / min, or from 20 m / min to 25 m / min, or from 25 m / min to 30 m / min, or from 30 m / min to 35 m / min, or from 35 m / min to 40 m / min.

[0116] According to preferred embodiments, the residence time of the composition to be treated in the column is at least 2 s. The residence time, also called the contact time, is the duration for which the composition to be treated remains in contact with the activated carbon in the column. Too short a residence time can lead to a reduction in the adsorption efficiency of the species to be removed. The residence time of the composition to be treated in the column is preferably at least 3 s. The residence time of the composition to be treated in the column may, in particular, be at least 4 s, or at least 5 s. Furthermore, the residence time of the composition to be treated generally does not exceed 30 s in the column. The residence time of the composition to be treated may, in particular, be less than 25 s, or less than 20 s.

[0117] The CT composition is advantageously passed through the column filled with the activated carbon bed in gaseous form.

[0118] Once the activated carbon is saturated with the chemical species to be removed, it can advantageously be regenerated by thermal desorption or desorption under reduced pressure. Thermal desorption can be carried out by heating to a temperature higher than that of the compound to be desorbed (180°C to 190°C for limonene). Desorption under reduced pressure can be carried out at a pressure of 25 millibars or less. Treated composition

[0119] The treatment process according to the invention makes it possible to obtain a treated composition CR, in which at least one chemical species of the composition CT has, at least in part, been removed.

[0120] A CRi composition is capable of being obtained by a process according to the invention applied to a CTi composition to be treated.

[0121] Composition Cri may include, in particular, 20 ppm or less, preferably 10 ppm or less, and more preferably 5 ppm or less, by moles of said at least one polymerization inhibitor, relative to the number of moles of said at least one (hydro)halogenated olefin of composition CRp. Such a composition may be used directly in a polymerization process. According to certain embodiments, composition CRi may include 4 ppm or less, or 3 ppm or less, or 2 ppm or less, or 1 ppm or less by moles of said at least one polymerization inhibitor, relative to the number of moles of said at least one (hydro)halogenated olefin.

[0122] The polymerization inhibitor generally remains detectable in trace amounts, i.e. at a proportion of at least 0.01 ppm in moles of said at least one polymerization inhibitor relative to the total number of moles in said at least one (hydro)halogenated olefin.

[0123] The (hydro)halogenated olefins and polymerization inhibitors are as described for the composition to be treated Cn.

[0124] Advantageously, the composition Cri is generally purer in said at least one (hydro)halogenated olefin than the composition to be treated CTi. Said at least one (hydro)halogenated olefin may represent at least 98.0%, or at least 99.0%, or at least 99.5%, or at least 99.6%, or at least 99.7%, or at least 99.8% by weight relative to the weight of composition CRi.

[0125] According to certain embodiments, the composition Cri may comprise at least 98.0%, or at least 99.0%, or at least 99.5%, or at least 99.6%, or at least 99.7%, or at least 99.8% by weight of at least one hydro(halogenated) olefin selected from vinyl fluoride, trifluoroethylene and tetrafluoroethylene, relative to the weight of composition CR[

[0126] According to certain embodiments, the CRi composition may comprise at least 98.0%, or at least 99.0%, or at least 99.5%, or at least 99.6%, or at least 99.7%, or at least 99.8% by weight of trifluoroethylene, relative to the weight of the Cri composition.

[0127] According to certain embodiments, in particular according to embodiments in which said at least one (hydro)halogenated olefin comprises trifluoroethylene, the polymerization inhibitor may be a limonene.

[0128] A composition CR2 is likely to be obtained by a process according to the invention applied to a composition to be treated C|2.

[0129] Advantageously, composition CR2 is generally purer in trifluoroethylene than composition CT2. Trifluoroethylene can represent at least 98.0%, or at least 99.0%, or at least 99.5%, or at least 99.6%, or at least 99.7%, or at least 99.8% by weight relative to the weight of composition CR2.

[0130] According to some embodiments, the CR2 composition may comprise at least 98.0%, or at least 99.0%, or at least 99.5%, or at least 99.6%, or at least 99.7%, or at least 99.8%, or at least 99.9% by weight of trifluoroethylene relative to the weight of the CR2 composition.

[0131] Advantageously, the CR2 composition may comprise a proportion YCF in the total of the (hydro)chlorofluorinated olefin(s) and (hydro)chlorofluorinated alkan(s) present in the CR2 composition, less than or equal to XCF / 2. The proportion YCF is expressed as the number of moles in parts per million of the total of the (hydro)chlorofluorinated olefin(s) and (hydro)chlorofluorinated alkan(s) present in the CR2 composition, relative to the number of moles of trifluoroethylene in the CR2 composition. Preferably, YCF is less than or equal to XCF / 3, and more preferably, it is less than or equal to XCF / 5.

[0132] According to certain embodiments, YCF is less than or equal to 50 ppm relative to the number of moles of trifluoroethylene in composition CR2. Preferably, YCF is less than or equal to 25 ppm, and more preferably, less than or equal to 10 ppm. In certain embodiments, YCF may be less than or equal to 5 ppm, or even less than or equal to 1 ppm. The (hydro)chlorofluorinated olefin(s) and (hydro)chlorofluorinated alkane(s) present generally remain detectable in trace amounts, i.e., at a YCF proportion of at least 0.01 ppm.

[0133] According to some embodiments, CR2 comprises chlorotrifluoroethylene, and at least one other chlorofluorinated or hydrochlorofluorinated compound.

[0134] According to some embodiments, CR2 comprises chlorotrifluoroethylene as the only chlorofluorinated or hydrochlorofluorinated compound in the composition.

[0135] According to some embodiments, the CR2 composition may comprise a proportion Yctpe of chlorotrifluoroethylene less than or equal to 50 ppm. The proportion YCTFF is expressed as the number of moles in parts per million of chlorotrifluoroethylene relative to the number of moles of trifluoroethylene in The CR2 composition. Preferably, YCTfe is less than or equal to 40 ppm, preferably less than or equal to 30 ppm, preferably less than or equal to 10 ppm, and even more preferably less than or equal to 10 ppm. In some embodiments, YCTfe may be less than or equal to 5 ppm, or even less than or equal to 1 ppm. Chlorotrifluoroethylene generally remains detectable in trace amounts, i.e., at a YCTfe concentration of at least 0.01 ppm.

[0136] According to some embodiments, Yctfe is less than or equal to XCtfe / 2, and preferably less than or equal to XCTfe / 3, and more preferably less than or equal to XCTfe / 5.

[0137] According to some embodiments, the CR2 composition may comprise a YVDf proportion of vinylidene fluoride from 1 ppm to 5000 ppm. The YVDf proportion is expressed as the number of moles in parts per million of vinylidene fluoride relative to the number of moles of trifluoroethylene in the CR2 composition. YVDf may be from 1 ppm to 100 ppm, or from 100 ppm to 250 ppm, or from 250 ppm to 500 ppm, or from 500 ppm to 1000 ppm, or from 1000 ppm to 2500 ppm, or from 250 ppm to 5000 ppm. According to some embodiments, YVDf may be from 250 ppm to 2500 ppm.

[0138] According to particular embodiments, the CR2 composition is essentially composed of trifluoroethylene and vinylidene fluoride. The trifluoroethylene and vinylidene fluoride may represent at least 99.90%, preferably at least 99.95%, and more preferably at least 99.98% by weight, relative to the weight of the CR2 composition. In these embodiments, YVDf advantageously ranges from 1 ppm to 5000 ppm. YVDf may be from 1 ppm to 100 ppm, or from 100 ppm to 250 ppm, or from 250 ppm to 500 ppm, or from 500 ppm to 1000 ppm, or from 1000 ppm to 2500 ppm, or from 250 ppm to 5000 ppm. According to some embodiments, YVDf may be from 250 ppm to 2500 ppm.

[0139] According to some embodiments, the CR2 composition may also comprise less than 50 ppm, preferably less than 10 ppm, and preferably even less than 5 ppm of 1,1 difluoroethane (HFC-152a), in moles of 1,1 difluoroethane relative to the number of moles of trifluoroethylene.

[0140] According to some embodiments, the CR2 composition may also comprise less than 50 ppm, preferably less than 10 ppm, and preferably even less than 5 ppm of 1,1,2 trifluoroethane (HFC-143), in moles of 1,1,2 trifluoroethane relative to the number of moles of trifluoroethylene.

[0141] In embodiments where CT2 comprises a polymerization inhibitor, for example limonene, the latter has been substantially eliminated by means of the process according to the invention. The composition CR2 then advantageously comprises 0.01 ppm to 10 ppm, and preferably from 0.01 ppm to 5 ppm in moles of polymerization inhibitor relative to the number of moles of trifluoroethylene in the composition.

[0142] CR2 compositions can be used in any process requiring high purity of trifluoroethylene and / or high purity of trifluoroethylene and vinylidene fluoride. In particular, the CR2 composition can be used for the manufacture of copolymers comprising, or essentially consisting of, repeating units resulting from the polymerization of vinylidene fluoride and trifluoroethylene.

[0143] Composition CR2 can also be used in other applications where high purity may be required. In particular, it can be used as a stripping or etching gas. Specifically, it can be useful for removing surface deposits in CVD (chemical vapor deposition) chambers or surface deposits in PEVD (plasma-enhanced chemical vapor deposition) chambers. It can also be useful for removing surface deposits from metals, cleaning plasma etching chambers, and removing nitrogen-containing thin films from a wafer. In some embodiments, it is used in an etching application.

[0144] A CRR2 composition can be obtained by a process according to the invention applied to a CTi_2 composition to be treated. The different embodiments for the CRi 2 composition can be obtained by combining embodiments developed for the Cri composition and embodiments developed for the CR2 composition. Examples

[0145] The following examples are provided for illustrative purposes only and should in no way be considered as limiting the scope of the invention.

[0146] A stainless steel column with an internal diameter of 42 mm, a usable length of 450 mm, and a cross-sectional area of ​​13.9 cm² was used to carry out the examples. Two temperature probes were placed at 1 / 3 and 2 / 3 of the column's length to monitor the column's internal temperature. Fresh activated carbon (280 g) was used to load the column. The carbon used was agglomerated bituminous carbon in granular form with an average particle diameter of 1.6 mm. It was characterized by an iodine value of 900 mg / g and a methylene blue value of 230 mg / g.

[0147] The gas composition to be treated Ct(Vf3) was a trifluoroethylene-based composition obtained by hydrogenolysis of chlorotrifluoroethylene and stabilized by limonene (see analysis in Table 2).

[0148] The treatment according to the invention was carried out at a pressure of 4.5 bar, taking care not to exceed a temperature of 28°C, particularly during the initial contact of the activated carbon with the gas composition to be treated. A valve was used to adjust the column inlet flow rate. Two experimental conditions were tested, the results of which are presented in Table 1 below.

[0149] [Tables 1] Experimental conditions #A #B Column pressure (bar arg) 4.5 4.5 Temperature (°C) 22 22 Total flow rate (kg / h) 5 2.77 Residence time (s) 8.9 16.0 Empty drum velocity (m / min) 3.0 1.7

[0150] Table 1

[0151] The composition to be treated Ct(Vf3), and the compositions CR(#A) and respectively CR(#B) obtained after treatment on the activated carbon column under conditions #A and respectively #B were analyzed as follows.

[0152] Trifluoroethylene and other "light" impurities were separated and quantified by gas chromatography and mass spectrometry (MS).

[0153] Limonene was separated and quantified by gas chromatography and photoionization detector (PID).

[0154] Each analysis was carried out on two samples of a composition, and the result presented corresponds to the average of the two measurements.

[0155] Table 2 presents the results of the chemical analyses. The results are expressed as in the invention: for trifluoroethylene as a mass percentage relative to the total weight of the composition, and for each other chemical species as a molar percentage relative to the number of moles of trifluoroethylene in the composition.

[0156] [Tables2] Chemical species (proportions) Composition Ct(VF3) CR(#A) CR(#B) Trifluoroethylene (% TrFE mass / weight composition) 99.07 99.85 99.81 1,1-Difluoroethene (ppm / mol TrFE) 1105 1882 2463 Chlorotrifluoroethylene (ppm / mol TrFE) 5148 <4 <4 1,1-Difluoroethane (ppm / mol TrFE) 127 <4 <4 Fluoroethane (ppm / mol TrFE) 9 <4 <4 1,1,2-Trifluoroethane (ppm / mol TrFE) 50 <4 <4 Limonene (ppm / mol TrFE) 632 <1 2.5

[0157] Table 2

[0158] Based on the results in Table 2, it can be seen that passing Ct(Vf3) through the activated carbon column substantially removed limonene. Furthermore, passing Ct(Vf3) through the activated carbon column substantially removed impurities other than 1,1-difluoroethene, and in particular chlorotrifluoroethylene, which represented 5148 ppm / mol of TrFE in CT(vf3) and less than 4 ppm / mol of TrFE in CR(#A) and CR(#B) (detection limit of the equipment used: additional analyses should be carried out to determine the exact value in ppb / mol of TrFE).

[0159] Trifluoroethylene essentially gained in purity by passing over the activated carbon column, since the purity increased from 99.07% for composition CT(vf3) to 99.85% and 99.81% for compositions CR(#A) and CR(#B).

Claims

Demands

1. A method for removing a polymerization inhibitor from a CTi composition to be treated, said Cn composition comprising at least one (hydro)halogenated olefin and at least one polymerization inhibitor of said at least one (hydro)halogenated olefin, said method comprising a step in which said CTi composition is passed through a column filled with a bed of activated carbon, in order to obtain a CRi composition, said CRi composition comprising said at least one (hydro)halogenated olefin and being essentially devoid of said at least one polymerization inhibitor.

2. Method according to claim 1, wherein said at least one (hydro)halogenated olefin is of formula (I): [Chem. 3] 0) in which Xi is selected from F and Cl, and where X2, X3 and X4 are independently selected from: H, F and Cl.

3. A method according to any one of claims 1 and 2, wherein said at least one hydro(halogenated) olefin is selected from vinyl fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, 1,1-chlorofluoroethylene, and mixtures thereof.

4. A method according to any one of claims 1 to 3, wherein the composition Cn comprises at least 90.0%, and preferably at least 95.0% by weight of trifluoroethylene, relative to the total weight of the composition.

5. A method according to any one of claims 1 to 4, wherein said at least one polymerization inhibitor is selected from monoterpenes, such as a limonene, a phellandrene, a pinene, camphene, myrcene, alpha-terpinene, gamma-terpinene; monoterpenoids, such as citronellol, terpineol and borneol; sesquiterpenes; sesquiterpenoids, diterpenes and diterpenoids.

6. A method according to any one of claims 1 to 5, wherein said at least one polymerization inhibitor is a limonene.

7. A process according to any one of claims 1 to 6, wherein said composition Cri comprises less than 20 ppm, preferably less than 10 ppm, and most preferably less than 5 ppm, in moles of said at least one polymerization inhibitor relative to the number of moles of said at least one (hydro)halogenated olefin in composition Cri.

8. A process according to any one of claims 1 to 7, wherein said composition Cn comprises more than 30 ppm by mole of said at least one polymerization inhibitor relative to the number of moles in said at least one (hydro)halogenated olefin in the composition CTi.

9. A process for purifying a CT2 composition comprising trifluoroethylene and at least one compound to be removed, at least in part, selected from a (hydro)chlorofluorinated olefin, a (hydro)chlorofluorinated alkane, or a mixture thereof, trifluoroethylene representing at least 90.0% by weight, and preferably at least 95.0% by weight relative to the total weight of composition CT2, and having a proportion XCf of the at least one compound to be removed, expressed in moles of the at least one compound to be removed relative to the number of moles of trifluoroethylene in composition CT2, said process comprising a step in which said composition CT2 is passed through a column packed with a bed of activated carbon, in order to obtain a CR2 composition, said composition CR2 comprising trifluoroethylene and the at least one compound to be removed, the proportion YCf of the at least one compound to be removed,expressed in moles of at least one compound to be eliminated relative to the number of moles of trifluoroethylene in composition CT2 being less than or equal to Xcf / 2, preferably less than or equal to XCF / 3, and more preferably less than or equal to XCf / 5.

10. A process according to claim 9, wherein at least one compound to be removed comprises chlorotrifluoroethylene.

11. A process according to claim 9, wherein at least one compound to be removed is chlorotrifluoroethylene.

12. A method according to any one of claims 1 to 8, or according to any one of claims 9 to 11, wherein the step in which the composition to be treated is passed through the filled column of the bed activated carbon is implemented with the said composition to be treated being in gaseous form.

13. A method according to any one of claims 1 to 8, or according to any one of claims 9 to 11, or according to claim 12, wherein the step in which said composition to be treated is passed through the column filled with the activated carbon bed, is carried out in such a way that the temperature in the column does not exceed 45°C, preferably does not exceed 40°C, preferably still does not exceed 35°C, and more preferably does not exceed 30°C.

14. A method according to any one of claims 1 to 8, or according to any one of claims 9 to 11, or according to any one of claims 12 to 13, wherein the step in which said composition to be treated is passed through the column filled with the activated carbon bed, is carried out such that the empty drum velocity of said composition to be treated in the column is from 1 m / min to 40 m / min, preferably from 1.5 m / min to 35 m / min, and more preferably from 2 m / min to 30 m / min.

15. A method according to any one of claims 1 to 8, or according to any one of claims 9 to 11, or according to any one of claims 12 to 14, wherein the step in which said composition to be treated is passed through the column filled with the activated carbon bed, is carried out in such a way that the residence time of said composition to be treated in the column is at least 2 s.

16. A method according to any one of claims 1 to 8, or according to any one of claims 9 to 11, or according to any one of claims 12 to 15, wherein said activated carbon of the activated carbon bed has an iodine value greater than or equal to 800 mg / g, and preferably greater than or equal to 850 mg / g, as measured in accordance with ASTM D4607-14(2021).

17. A method according to any one of claims 1 to 8, or according to any one of claims 9 to 11, or according to any one of claims 12 to 16, wherein said activated carbon of the activated carbon bed has an iodine value less than or equal to 1200 mg / g, preferably less than or equal to 1100 mg / g, preferably still less than or equal to 1050 mg / g, and preferably less than or equal to 1025 mg / g, as measured according to ASTM D4607-14(2021).

18. Composition comprising at least 98.0%, preferably at least 99.0%, and more preferably at least 99.5% by weight of trifluoroethylene relative to the total weight of the composition, and from 0.01 ppm to 50 ppm by mole of chlorofluorinated or hydrochlorofluorinated compound(s) relative to the number of moles of trifluoroethylene in the composition.

19. Composition according to claim 18, comprising chlorotrifluoroethylene, and at least one other chlorofluorinated or hydrochlorofluorinated compound.

20. Composition according to claim 18, comprising chlorotrifluoroethylene as the only chlorofluorinated or hydrochlorofluorinated compound in the composition.

21. Composition according to any one of claims 18 to 20, comprising from 0.01 ppm to 10 ppm, and preferably from 0.01 ppm to 5 ppm in moles of a trifluoroethylene polymerization inhibitor, relative to the number of moles of trifluoroethylene in the composition.

22. Composition according to claim 21, wherein said trifluoroethylene polymerization inhibitor is a limonene.

23. Composition according to any one of claims 18 to 22, comprising from 1 ppm to 5000 ppm in moles of vinylidene fluoride, relative to the number of moles of trifluoroethylene in the composition.

24. Composition according to claim 23 comprising from 250 ppm to 2500 ppm of vinylidene fluoride, relative to the number of moles of trifluoroethylene in the composition.

25. Composition according to any one of claims 18 to 24, comprising vinylidene fluoride, wherein the total weight of trifluoroethylene and vinylidene fluoride represents at least 99.90%, preferably at least 99.95%, and more preferably at least 99.98% by weight, relative to the weight of the composition.

26. Composition comprising at least 98.0%, and preferably at least 99.5%, by weight of trifluoroethylene, relative to the total weight of the composition, and from 0.01 ppm to 10 ppm, preferably of 0.01 ppm to 5 ppm in moles of a polymerization inhibitor relative to the number of moles of trifluoroethylene in the composition.

27. ​​Use of a composition according to any one of claims 18 to 26, for the polymerization of a polymer comprising, or being essentially made up of, or being made up of, repeating units resulting from the polymerization of vinylidene fluoride and trifluoroethylene.

28. Use of a composition according to any one of claims 18 to 26, as a pickling or etching gas.