Stabilized (hydro)halogenated olefin compositions

Abstract

The present invention relates to at least one (hydro)halogenated olefin having the following chemical formula: CX1X2=CX3X4(I) (wherein X1 is selected from F and Cl; X2, X3 and X4 are independently selected from H, F and Cl; and - at least one aliphatic alkene having a boiling point below 80 °C measured at 1013 hPa A composition comprising: It relates to a composition, wherein said (hydro)halogenated olefin is either solely in gaseous form or in the form of a liquid-gas equilibrium.

Description

[Technical field]

[0001] The present invention relates to the field of hydro(halogenated)olefins having two carbon atoms, and in particular to their stabilization with polymerization inhibitors. [Background technology]

[0002] For many ethylene monomers in the polymer manufacturing industry, a major problem concerns the storage and / or transportation of these monomers.

[0003] Indeed, spontaneous uncontrolled polymerization of these monomers can occur over time from free radicals generated in particular by residual diatomic oxygen, even in trace amounts.

[0004] For (hydro)halogenated olefins with 2 carbon atoms, a particular group of compounds, the terpenes, are commonly used as stabilizers / inhibitors of polymerization. Among the terpenes, limonene, also called dipentene, is particularly known. Patent US2407405 discloses the stabilization of TFE during storage and handling by adding 0.5% of terpene "B". Trifluoroethylene, which is essentially a mixture of dipentene and terpinolene, is commonly sold stabilized with limonene (see Safety Data Sheet for Trifluoroethylene sold by Halocarbon - XP002673763).

[0005] One of the disadvantages of these organic compounds used as polymerization inhibitors is their relatively high molecular weight, and especially their high boiling point (for example, 176° C. for dipentene), compared to (hydro)halogenated olefins having two carbon atoms (for example, −72° C. for vinyl fluoride, −76° C. for tetrafluoroethylene, −61° C. for trifluoroethylene). Indeed, since (hydro)halogenated olefins having two carbon atoms are generally stored in compressed gas form, optionally liquefied, i.e. solely in gas form or in liquid-vapor equilibrium, this large difference in boiling point, and therefore in partial pressure, results in low or even very low concentrations of the inhibitor in the monomer gas phase.

[0006] This amount may prove insufficient to protect the monomer from spontaneous polymerization in a sustainable and reliable manner.

[0007] Another drawback of these compounds is their toxicity, which is often high, both to human health, as well as to aquatic life and the environment. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] U.S. Patent No. 2,407,405 [Non-patent literature]

[0009] [Non-Patent Document 1] Safety Data Sheet for Trifluoroethylene sold by Halocarbon - XP002673763 Summary of the Invention [Problem to be solved by the invention]

[0010] It is therefore an object of the present invention to provide an alternative inhibitor for the polymerization of (hydro)halogenated olefins having two carbon atoms which does not exhibit the disadvantages of the inhibitors described in the prior art. [Means for solving the problem]

[0011] The present invention relates to at least one (hydro)halogenated olefin having the following chemical formula: CX1X2=CX3X4(I) (Wherein, X1 is selected from F and Cl; X2, X3 and X4 are independently selected from H, F and Cl; and - at least one aliphatic alkene having a boiling point below 80 °C measured at 1013 hPa A composition comprising: It relates to a composition, wherein said (hydro)halogenated olefin is either solely in gaseous form or in the form of a liquid-gas equilibrium.

[0012] The inventors of the present invention have surprisingly realised that aliphatic alkenes having a boiling point below 80° C. can act as polymerization inhibitors for the (hydro)halogenated olefins of formula (I). Furthermore, due to their low boiling point, these inhibitors offer the advantage that they can be introduced at higher gas phase contents than terpenes.

[0013] In some embodiments, the (hydro)halogenated olefin of formula (I) is selected from the group consisting of vinyl chloride, vinyl fluoride, 1,1-dichloroethene, 1,2-dichloroethene, 1,1-difluoroethene, 1,2-difluoroethene, trifluoroethylene, chlorotrifluoroethylene, 1,1-chlorofluoroethene, 1,2-chlorofluoroethene, 1-chloro-2,2-difluoroethylene, tetrafluoroethylene, and mixtures thereof.

[0014] In some embodiments, the (hydro)halogenated olefin of formula (I) may essentially comprise an element selected from the group consisting of trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, 1,1-chlorofluoroethene, and mixtures thereof, and is preferentially selected from the group consisting of trifluoroethylene, tetrafluoroethylene, and mixtures thereof.

[0015] In some particular embodiments, the (hydro)halogenated olefin of formula (I) may essentially comprise trifluoroethylene.

[0016] "Essentially comprising" is understood in this specification to mean that the (hydro)halogenated olefins referred to represent more than 95% by weight, preferentially more than 96% by weight, preferentially more than 97% by weight, preferentially even more than 98% by weight and more preferably more than 99% by weight, based on all the (hydro)halogenated olefins considered.

[0017] In some embodiments, the (hydro)halogenated olefin of formula (I) may be selected from the group consisting of trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene, 1,1-chlorofluoroethene, and mixtures thereof, and is preferentially selected from the group consisting of trifluoroethylene, tetrafluoroethylene, and mixtures thereof.

[0018] In some particular embodiments, the (hydro)halogenated olefin of formula (I) may be trifluoroethylene.

[0019] In some embodiments, the aliphatic alkene may have a boiling point, measured at 1013 hPa, at most equal to 60° C., preferentially at most equal to 50° C. This has the advantage that the aliphatic alkene can be introduced at a high gas phase content.

[0020] In some embodiments, the aliphatic alkene is a C3-C6 alkene compound containing a single double bond, which may in particular be selected from the group consisting of propene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-hexene, 2-hexene, 3-hexene, isomers of methylpentene, in particular 4-methyl-1-pentene, isomers of dimethylbutene, cyclopentene, and mixtures thereof.

[0021] The aliphatic alkene is in particular selected from the group consisting of 1-butene, 2-butene, isobutylene and mixtures thereof.

[0022] In some embodiments, the (hydro)halogenated olefin of formula (I) is solely in gaseous form. Storage in this form is particularly recommended for certain monomers, such as trifluoroethylene.

[0023] In some embodiments, the aliphatic alkene is in liquid-vapor equilibrium, which allows the gas phase to be saturated with aliphatic alkene vapor.

[0024] In some embodiments, the (hydro)halogenated olefin of formula (I) represents at least 90 wt.%, or at least 91 wt.%, or at least 92 wt.%, or at least 93 wt.%, or at least 94 wt.%, or at least 95 wt.%, or at least 96 wt.%, or at least 97 wt.%, or at least 98 wt.%, or at least 99 wt.%, based on the total composition weight.

[0025] In some embodiments, the composition consists essentially of one or more (hydro)halogenated olefins and aliphatic alkenes.

[0026] The composition may contain a low content of diatomic oxygen, in particular diatomic oxygen gas. The diatomic oxygen content may be 2500 molar ppm or less, preferentially 1000 molar ppm or less, preferentially 500 molar ppm or less, and preferentially even 100 molar ppm or less, relative to the number of moles of (hydro)halogenated olefin in the gas phase. In general, it is desirable to have as low a diatomic oxygen content as possible in the composition. However, since having a high content of aliphatic alkenes in the gas phase may inhibit polymerization, in some embodiments, certain tolerances may be envisaged. The diatomic oxygen content may be strictly more than 3 molar ppm, or strictly more than 50 molar ppm, or strictly more than 100 ppm, or strictly more than 300 ppm, or strictly more than 1000 molar ppm, relative to the number of moles of (hydro)halogenated olefin in the gas phase.

[0027] In some embodiments, the composition may comprise more than 100 molar ppm, preferentially more than 250 molar ppm, more preferentially more than 500 molar ppm, more preferentially more than 750 molar ppm, more preferably more than 1000 molar ppm of said aliphatic alkene in the gas phase relative to the number of moles of (hydro)halogenated olefin in the gas phase.

[0028] In some embodiments, the composition may contain less than 50000 molar ppm, preferentially less than 25000 molar ppm, more preferably less than 10000 molar ppm of said aliphatic alkene in the gas phase relative to the number of moles of (hydro)halogenated olefin in the gas phase. The composition may in particular contain less than 7500 molar ppm, or less than 5000 molar ppm, of said aliphatic alkene in the gas phase relative to the number of moles of (hydro)halogenated olefin in the gas phase.

[0029] In some embodiments, the composition may comprise from 1 molar ppm to 100 molar ppm, or from 100 molar ppm to 1000 molar ppm, or from 1000 molar ppm to 2000 molar ppm, or from 2000 molar ppm to 3000 molar ppm, or from 3000 molar ppm to 4000 molar ppm, or from 4000 molar ppm to 5000 molar ppm, or from 5000 molar ppm to 6000 molar ppm, or from 6000 molar ppm to 7000 molar ppm, or from 8000 molar ppm to 9000 molar ppm, or from 9000 molar ppm to 10000 molar ppm of said at least one aliphatic alkene in the gas phase, particularly relative to the number of moles of (hydro)halogenated olefin in the gas phase.

[0030] The present invention also relates to the use of aliphatic alkenes such as those mentioned above to stabilise hydro(halogenated)olefins of formula (I) such as those mentioned above, in particular to avoid any self-polymerisation thereof.

[0031] The above described compositions can be advantageously used for the storage of hydro(halogenated)olefins of formula (I). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] One particular embodiment provides a composition comprising trifluoroethylene and a butene, such as but-1-ene, where the butene inhibits the polymerization, and in particular the self-polymerization, of trifluoroethylene.

[0033] This composition may allow trifluoroethylene to be stored and / or transported, particularly while avoiding self-polymerization of the monomer.

[0034] The trifluoroethylene of the composition may be in compressed gas form, or may optionally be liquefied, and therefore may be solely in gas form or in the form of a gas-liquid equilibrium.

[0035] The butenes of the composition may also be solely in gaseous form or in the form of a gas-liquid equilibrium.

[0036] In some embodiments, the composition comprising trifluoroethylene and butene that can be used to store trifluoroethylene may be solely in gaseous form.

[0037] In some embodiments, compositions comprising trifluoroethylene and butenes that can be used to store trifluoroethylene can include a gas phase and a liquid phase, with the liquid phase consisting essentially of butenes.

[0038] Various processes are known for producing trifluoroethylene. Among these processes, the production of trifluoroethylene by hydrogenolysis of chlorotrifluoroethylene is particularly known. Such a process is described, for example, in application EP2819979 or application EP2993213 (Example 1). At the end of the process, a distillation step allows to recover pure or substantially pure trifluoroethylene or trifluoroethylene that still contains small amounts of impurities, depending on the distillation conditions.

[0039] In some embodiments, the trifluoroethylene may have a purity of 95.0% by weight or more, preferentially 98.0% by weight or more, and very preferably 99.0% by weight or more. In a particular embodiment, the trifluoroethylene may have a purity of 99.5% or more.

[0040] For example, document EP 2993213 shows the preparation of trifluoroethylene with a purity equal to 99.1% containing other hydrogenated olefins as impurities, in particular chlorotrifluoroethylene, isomers of difluoroethylene and isomers of chlorodifluoroethylene, as well as alkanes. The use of aliphatic alkenes as inhibitors for the polymerization of hydro(halogenated)olefins as claimed herein has not been found.

[0041] The trifluoroethylene thus produced can be stored in a suitable pressure-resistant container. It is stored in the presence of butene in gas form with a gaseous content of 1 molar ppm to 100,000 ppm, preferentially 50 ppm to 75,000 ppm, more preferentially 100 ppm to 50,000 ppm, even more preferentially 500 ppm to 25,000 ppm, and very preferably 1,000 ppm to 10,000 ppm, relative to trifluoroethylene. In particular, trifluoroethylene can be stored in the presence of butene in gas form with a gaseous content of 1,000 ppm to 5,000 ppm relative to trifluoroethylene.

[0042] Prior to the introduction of the composition comprising trifluoroethylene and / or butene and / or trifluoroethylene and butene, the diatomic oxygen content in the vessel can be reduced to a predetermined threshold by reducing the internal pressure and / or by injecting an inert gas.

[0043] The composition may be stored under normal conditions of pressure and temperature.

[0044] The storage temperature may vary, in particular between -20°C and +40°C, or between 10°C and +35°C, or between 0°C and 30°C.

[0045] The storage pressure is generally greater than or equal to 1 bar and less than or equal to 20 bar.

[0046] The pressure may in particular be 1.5 bar or more, or 2 bar or more, or 2.5 bar or more, or 3 bar or more, or 3.5 bar or more. A pressure of 3.5 bar or more exceeds the recommended pressure threshold for storing trifluoroethylene containing less than 1000 ppm dipentene in the gas phase (see the safety data sheet for trifluoroethylene sold by Halocarbon - XP002673763).

[0047] The pressure may in particular be less than or equal to 19 bar, or less than or equal to 18 bar, or less than or equal to 17 bar, or less than or equal to 16 bar, or less than or equal to 15 bar.

[0048] In some embodiments, the storage pressure is between 3.5 bar and 15 bar. EXAMPLES

[0049] In the following experiments, trifluoroethylene purified to 99.9% and but-1-ene with a purity equal to 99.6% were used.

[0050] Chromatographic analysis of trifluoroethylene showed that, among the impurities present, chlorotrifluoroethylene and vinylidene fluoride appeared among other aliphatic alkenes, and thus the chromatographic analysis also showed that the trifluoroethylene contained no aliphatic alkenes, much less but-1-ene.

[0051] [Example 1] In a 4 L reactor containing 3400 g of demineralized water, 1 g of methylhydroxypropylcellulose and 1.8 g of propylperoxydicarbonate, a quantity of 166 g of trifluoroethylene was reacted with a quantity of 280 g of vinylidene fluoride and 17 g of chlorotrifluoroethylene in the presence of 0.45 g of but-1-ene (i.e. 950 molar ppm relative to the total number of moles of monomers that are (hydro)(chloro)fluorinated olefins). The reactor was then brought to a temperature of 44° C. as quickly as possible in order to reach a pressure of 95 bar. Once at a temperature of 44° C., the polymerization reaction only started after an inhibition period equal to 82 minutes, which is considered to have started after the pressure in the reactor had dropped by 5 bar.

[0052] [Comparative Example] The comparative example was carried out under the same conditions as Example 1, except that no but-1-ene was added to the reaction mixture. The reactor was brought to a temperature of 44° C. as quickly as possible, and the pressure in the reactor was less than 90 bar when the target temperature was reached, indicating that the polymerization reaction had started as the temperature increased in the reactor.

[0053] But-1-ene is therefore an inhibitor of the polymerization of trifluoroethylene.

Claims

1. at least one (hydro)halogenated olefin having the following formula: CX １ X ２ =CX ３ X ４ (I) (In the formula, X １ is selected from F and Cl; X ２ , X ３ and X ４ are independently selected from H, F and Cl; and at least one aliphatic alkene having a boiling point, measured at 1013 hPa, of not more than 80°C; A composition comprising: A composition wherein the (hydro)halogenated olefin is solely in gaseous form or in the form of a liquid-gas equilibrium.

2. 2. The composition of claim 1, wherein the (hydro)halogenated olefin of formula (I) is selected from the group consisting of vinyl chloride, vinyl fluoride, 1,1-dichloroethene, 1,2-dichloroethene, 1,1-difluoroethene, 1,2-difluoroethene, trifluoroethylene, chlorotrifluoroethylene, 1,1-chlorofluoroethene, 1,2-chlorofluoroethene, 1-chloro-2,2-difluoroethylene, tetrafluoroethylene, and mixtures thereof.

3. The composition of claim 1, wherein the (hydro)halogenated olefin of formula (I) is selected from the group consisting of trifluoroethylene, tetrafluoroethylene, and mixtures thereof.

4. 2. The composition of claim 1, wherein the aliphatic alkene has a boiling point, measured at 1013 hPa, of at most 60°C.

5. 2. The composition of claim 1, wherein the aliphatic alkene is a C3-C6 alkene compound containing a single double bond.

6. 2. The composition of claim 1, wherein the aliphatic alkene is selected from the group consisting of propene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, 1-hexene, 2-hexene, 3-hexene, isomers of methylpentene, especially 4-methyl-1-pentene, isomers of dimethylbutene, cyclopentene, and mixtures thereof.

7. 2. The composition of claim 1, wherein the aliphatic alkene is selected from the group consisting of 1-butene, 2-butene, isobutylene, and mixtures thereof.

8. 2. The composition of claim 1, wherein the (hydro)halogenated olefin is solely in gaseous form.

9. The composition of claim 1, wherein the aliphatic alkene is in liquid-gas equilibrium.

10. 2. The composition of claim 1, wherein the (hydro)halogenated olefin represents at least 90 wt.%, or at least 91 wt.%, or at least 92 wt.%, or at least 93 wt.%, or at least 94 wt.%, or at least 95 wt.%, or at least 96 wt.%, or at least 97 wt.%, or at least 98 wt.%, or at least 99 wt.%, based on the total composition weight.

11. 2. The composition of claim 1, comprising more than 100 mole ppm of said aliphatic alkene in the gas phase relative to the number of moles of (hydro)halogenated olefin in the gas phase.

12. The composition of claim 1, comprising more than 500 mole ppm of said aliphatic alkene in the gas phase relative to the number of moles of (hydro)halogenated olefin in the gas phase.

13. 2. The composition of claim 1, comprising less than 50,000 mole ppm of said aliphatic alkene in the gas phase relative to the number of moles of (hydro)halogenated olefin in the gas phase.

14. The composition of claim 1, comprising less than 10,000 mole ppm of said aliphatic alkene in the gas phase relative to the number of moles of (hydro)halogenated olefin in the gas phase.

15. 1. Use of at least one aliphatic alkene having a boiling point of 80° C. or less measured at 1013 hPa to stabilize at least one (hydro)halogenated olefin having the following chemical formula: CX １ X ２ =CX ３ X ４ (I) (In the formula, X １ is selected from F and Cl; X ２ , X ３ and X ４ are independently selected from H, F, and Cl.