AROMATIC EUTECTIC MIXTURES AND THEIR USES AS SOLVENTS, PARTICULARLY IN LIQUID-LIQUID SEPARATION

Abstract

The present invention relates to aromatic and polyaromatic eutectic mixtures and their uses as solvents, particularly in liquid-liquid separation. (no figure)

Description

Title of the invention: AROMATIC EUTECTIC MIXTURES AND THEIR USES AS SOLVENTS, PARTICULARLY IN LIQUID-LIQUID SEPARATION

[0001] The present invention relates to aromatic and polyaromatic eutectic mixtures and their uses as solvents, particularly in liquid-liquid separation.

[0002] Extraction using an organic solvent is a commonly used method, particularly in chemical engineering and analytical chemistry, for extracting, but also separating and purifying, one or more chemical compounds. It generally involves taking one or more chemical species (or extractables) from a liquid or solid mixture, or from a suspension of a solid in a liquid.

[0003] Typically, an extraction method is used to selectively extract one or more compounds from an initial mixture, based on chemical or physical properties. The extraction medium is not or only slightly miscible with the main components of the initial mixture, and the compound to be extracted has more affinity for the extraction medium than for the main components of the initial mixture.

[0004] The extraction operation takes place in two parts: a first part of transferring the compound to be extracted between the initial mixture and the extraction means; a second part of separating the extraction means from the main mixture.

[0005] This extraction method is generally an organic solvent.

[0006] In a liquid-liquid extraction, one (or more) substance(s) dissolved in a solvent (feed phase, generally aqueous) is extracted using another solvent, called the extraction solvent phase (generally organic), in which it is more soluble. The initial solvent and the extraction solvent must not be miscible. This technique relies on the differential solubility of the substances to be extracted in two immiscible liquid phases.

[0007] In a solid-liquid extraction, the aim is to extract a substance present in a solid and transfer it into a liquid solvent. Maceration, infusion, and decoction are solid-liquid extraction methods.

[0008] However, the organic solvents traditionally used in this context are generally highly flammable, which complicates their handling and storage and makes them risky. Indeed, these organic solvents typically have fairly low flash points, typically <100°C. This represents a major risk to the safety of these applications, which are likely to use a large volume of these solvents.

[0009] Furthermore, organic solvents are often volatile and contribute to air pollution. Their improper handling can lead to soil and water contamination. They also threaten the health of the operators involved, including headaches, nausea, and in severe cases, neurological and / or carcinogenic / mutagenic effects.

[0010] The search for safer, less toxic, and more environmentally friendly solvents to minimize health and environmental risks while maintaining or even improving the efficiency of extraction processes is a priority. To overcome this volatility problem, researchers have created numerous polar and nonpolar eutectic solvents. These eutectic solvents are mixtures of molecules with liquefaction points close to room temperature. However, these eutectic solvents have little affinity for many molecules, particularly those containing aromatic residues.

[0011] The invention thus aims to provide compositions that, as a solvent, overcome the aforementioned drawbacks and in particular to provide for the first time a liquid aromatic eutectic solvent at room temperature.

[0012] An objective of the invention is to provide compositions with low flammability, in particular having flash points > 100 °C, reducing the aforementioned risks, while being able to be used as an aromatic solvent.

[0013] Another objective of the invention is to provide such compositions, which are at least equivalent to, or even more effective than, traditionally used solvents, for example toluene, particularly in liquid / liquid extraction. SUBJECT OF THE INVENTION

[0014] Thus, according to a first aspect, the invention relates to a composition consisting of or comprising at least two compounds selected from: - Di-tert-butyl-benzenes; - Biphenyls and terphenyls, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Polycyclic aromatic hydrocarbons selected from naphthalenes, acenaphthenes, anthracenes, pyrenes, which are optionally substituted by two groups selected independently from linear or branched alkyls in C1 to C6; - Fluorenes and carbazoles, which are optionally substituted by two or four groups chosen independently from linear or branched alkyls in C1 to C6; - 2,5-Diphenyloxazoles, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Compounds with formula (I): M\ . Rjj ' Rc

[0015] in which:

[0016] i is equal to 0 or 1;

[0017] Ra, Rb, Rc and Rd are independently chosen from H and phenyl, at least two of the groups Ra, Rb, Rc and Rd being a phenyl;

[0018] said compounds of formula (I) being optionally substituted, in particular on the phenyl groups, by two groups chosen independently from linear or branched alkyls at C1 to C6;

[0019] said composition not being made up of the biphenyl and naphthalene couple.

[0020] Surprisingly, it has been highlighted by the Inventors that these compounds have a melting point >60°C individually, but which, once within a composition according to the invention, have a lower melting point, or even liquid at room temperature, within a purely aromatic, or even poly-aromatic, eutectic.

[0021] And some compounds prove to be excellent solvents, particularly for molecules containing aromatic residues. For example, the compounds of the invention are more effective than toluene in liquid-liquid separation involving these molecules.

[0022] According to one embodiment, the composition according to the invention is eutectic.

[0023] According to one embodiment, the at least two compounds are in particular chosen among the following compounds:

[0024] in which Ri and R2 are chosen independently from one compound to another,

[0025] Ri being chosen from H and linear or branched alkyls at C1 to C6, and R2 being chosen from H and linear or branched alkyls from Ci to C6.

[0026] According to one embodiment, the composition of the invention is binary, tertiary, quaternary, quinquenar and so on depending on the number of components.

[0027] According to one embodiment, the composition of the invention is binary, tertiary, quaternary, quinquenaire.

[0028] According to one embodiment, the composition of the invention is: - binary, and the two compounds of said composition are present in it at a level of 20 to 80 mol%, in particular at a level of 40 to 60 mol%; - tertiary, and the three compounds of said composition are present in it at a rate of 10 to 55 mol%, in particular at a rate of 25 to 40 mol%; - quaternary, and the four compounds of said composition are present therein at a level of 5 to 45 mol%, in particular at a level of 22 to 40 mol% for three of them, and at a level of 6 to 34 mol% for the last; or - quinquénaire, and the five compounds of said composition are present in it at a level of 5 to 45% molar.

[0029] According to another aspect, the invention also relates to the use of a composition as a solvent, said composition being made up of or comprising at least two compounds selected from: - Di-tert-butyl-benzenes; - Biphenyls and terphenyls, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Polycyclic aromatic hydrocarbons selected from naphthalenes, acenaphthenes, anthracenes, pyrenes, which are optionally substituted by two groups selected independently from linear or branched alkyls in C1 to C6; - Fluorenes and carbazoles, which are optionally substituted by at least two groups chosen independently from linear or branched alkyls at C1 to C6; - 2,5-Diphenyloxazoles, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Compounds with formula (I): Rs R / ' W ! R.

[0030] in which:

[0031] i is equal to 0 or 1;

[0032] Ra, Rb, Rc and Rd are independently chosen from H and phenyl, at least two of the groups Ra, Rb, Rc and Rd being a phenyl;

[0033] said compounds of formula (I) being optionally substituted, in particular on the phenyl groups, by two groups chosen independently from linear or branched alkyls at C1 to C6.

[0034] Surprisingly, it has been highlighted by the Inventors that these compounds have a melting point >60°C individually, but which, once within a composition according to the invention, have a lower melting point, or even liquid at room temperature, within a purely aromatic, or even poly-aromatic, eutectic.

[0035] These purely aromatic, or even poly-aromatic, eutectic compositions prove to be excellent solvents with unique physicochemical characteristics, particularly for molecules containing aromatic residues. For example, the compounds of the invention are more effective than toluene in liquid-liquid separation involving these molecules.

[0036] According to one embodiment, said composition is devoid of another solvent, the other solvent being different from all the compounds defined above and their mixtures.

[0037] According to one embodiment, said use of the invention is a use of the composition as defined above for liquid-liquid separation, liquid-liquid-liquid separation, solid-liquid separation, or solid-liquid-liquid separation.

[0038] According to one embodiment, said use of the invention is a use of the composition as defined above for liquid-liquid separation, one of the liquid phases being an aqueous phase, the other liquid phase comprising or being made up of said composition.

[0039] According to one embodiment, said use of the invention is a use of the composition as defined above for the extraction of a compound, said compound being in particular chosen from organic compounds and metals, organic compounds being in particular aromatic or heteroaromatic compounds, or comprising aromatic or heteroaromatic groups,

[0040] According to one embodiment, said organic compounds, in particular aromatic or heteroaromatic compounds, or compounds comprising aromatic or heteroaromatic groups, are selected from: - Phytosanitary compounds, - Organic pollutants, particularly persistent ones, for example dioxins, - Microplastics, - Medications, - Dyes, and - Carbon black. DETAILED DESCRIPTION OF THE INVENTION Definitions

[0041] As understood here, value ranges in the form of "xy" or "from x to y" or "between x and y" include the bounds x and y, as well as the integers between these bounds, and the positive real numbers between these bounds and / or integers. For example, "1-5", or "from 1 to 5", or "between 1 and 5" denotes the integers 1, 2, 3, 4, and 5. Preferred embodiments include each integer taken individually within the value range, as well as any subcombination of these integers. For example, preferred values ​​for "1-5" may include the integers 1, 2, 3, 4, 5, 1-2, 1-3, 1-4, 1-5, 2-3, 2-4, 2-5, etc.

[0042] As used herein, the term "alkyl" refers to a linear or branched alkyl group having the number of carbon atoms indicated before said term, in particular 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, etc. Thus, an expression such as "C1 to C4 alkyl" refers to an alkyl radical containing 1 to 4 carbon atoms.

[0043] By "said composition is not composed of biphenyl and naphthalene", it is understood in particular that said composition is not a mixture consisting of unsubstituted biphenyl and unsubstituted naphthalene. In particular, said composition is not composed of biphenyl, optionally substituted by two groups independently selected from linear or branched alkyl groups at C1 to C6, and naphthalene, optionally substituted by two groups independently selected from linear or branched alkyl groups at C1 to C6.

[0044] The compositions of the invention are eutectics.

[0045] By "eutectic" is meant in particular a mixture of two or more substances which has a melting point lower than that of each of the individual substances.

[0046] The invention relates in particular to a composition consisting of or comprising at least two compounds selected from: - Biphenyls and terphenyls, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Polycyclic aromatic hydrocarbons selected from naphthalenes, acenaphthenes, anthracenes, pyrenes, which are optionally substituted by two groups selected independently from linear or branched alkyls in C1 to C6; - Fluorenes and carbazoles, which are optionally substituted by two or four groups chosen independently from linear or branched alkyls in C1 to C6; - 2,5-Diphenyloxazoles, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Compounds with formula (I):

[0047] [Chem.l] Ra

[0048] in which:

[0049] i is equal to 0 or 1;

[0050] Ra, Rb, Rc and Rd are independently chosen from H and phenyl, at least two of the groups Ra, Rb, Rc and Rd being a phenyl;

[0051] said compounds of formula (I) being optionally substituted, in particular on the phenyl groups, by two groups chosen independently from linear or branched alkyls at C1 to C6;

[0052] said composition not being composed of biphenyl and naphthalene.

[0053] The invention relates in particular to a composition consisting of or comprising at least two compounds selected from:

[0054] in which Ri and R2 are chosen independently from one compound to another,

[0055] Ri being chosen from H and linear or branched alkyls at C1 to C6, and R2 being chosen from H and linear or branched alkyls from Ci to C6.

[0056] Di-tert-butyl-benzene is in particular 1,4-di-tert-butyl-benzene.

[0057] Biphenyls and terphenyls include, in particular, biphenyl or para-terphenyl.

[0058] Optionally substituted biphenyls are in particular of the following formula: he

[0059]

[0060] in which Ri is chosen from H and linear or branched alkyls from C1 to C6. Optionally substituted terphenyls notably have the following formula: R, '

[0061]

[0062] in which Ri is chosen from H and linear or branched alkyls from C1 to C6. The naphthalenes optionally have one of the following formulas:

[0063]

[0064]

[0065] ! R, R. in which Ri is chosen from H and linear or branched alkyls from Ci to C6. Acenaphthenes, in particular, is unsubstituted. Optionally substituted anthracenes include the following formula: RJ

[0066]

[0067] in which Ri is chosen from H and linear or branched alkyls at C6 to C6, and R2 is chosen from H and linear or branched alkyls at C6 to C6. The pyrenes optionally have the following formula:

[0068] wherein Ri is selected from H and linear or branched alkyls at Ci to C6.

[0069] Optionally, 2,5-diphenyloxazoles are in particular of the following formula: Ri

[0070] in which Ri is selected from H and linear or branched alkyls at Ci to C6.

[0071] The optionally substituted fluorenes are in particular of the following formula:

[0072] wherein Ri is selected from H and linear or branched alkyls from C1 to C6, and R2 is chosen from H and linear or branched alkyls from Ci to C6.

[0073] Optionally substituted carbazoles are in particular of the following formula: R? .....( y*,

[0074] in which Ri is selected from H and linear or branched alkyls at C6 to Ci, and R2 is selected from H and linear or branched alkyls at C6 to Ci.

[0075] The compounds of formula (I) are in particular selected from 1,2-diphenylethens, 1,1,2,2-tetraphenylethens, 1,2-diphenylbutadiens, 1,1,4,4-tetraphenylbutadiens, optionally substituted, in particular on the phenyl groups, by two groups selected independently from linear or branched alkyls at C1 to C6.

[0076] The optional 1,2-diphenylethens are in particular of the following formula: RC '

[0077] wherein Ri is selected from H and linear or branched alkyls from C1 to C6.

[0078] The 1,1,2,2-tetraphenylethens optionally have, in particular, the formula next:

[0079] wherein Ri is selected from H and linear or branched alkyls at Ci to C6.

[0080] The optional 1,2-diphenylbutadienes are in particular of the following formula: y '

[0081] wherein Ri is selected from H and linear or branched alkyls at Ci to C6.

[0082] The optional 1,1,4,4-tetraphenylbutadienes are in particular of the formula next:

[0083] in which Ri is selected from H and linear or branched alkyls at Ci to C6.

[0084] The composition according to the invention may be a composition in which the aux at least two compounds have the same formula as defined above, differing only in the meaning of the Ri and / or R2 group.

[0085] According to a particular embodiment, the composition according to the invention consists of at least two compounds as defined above.

[0086] The composition, in particular the eutectic, according to the invention, can be binary (two-component), tertiary (three-component), quaternary (four-component), quinquenarian (five-component), and so on.

[0087] According to one embodiment, the composition of the invention is tertiary, quaternary, or quinquenaire. This is likely to allow the obtaining, if desired, of compositions with a lower melting temperature, for example much lower than ambient temperature.

[0088] According to a particular embodiment, the composition consists of or comprises: - a biphenyl, optionally substituted by two groups chosen independently from linear or branched alkyls from C1 to C6, in particular biphenyl; and - a 2,5-diphenyloxazole, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6, in particular 2,5-diphenyloxazole.

[0089] According to a particular embodiment, the composition consists of or comprises: - a biphenyl, optionally substituted by two groups chosen independently from linear or branched alkyls from C1 to C6, in particular biphenyl; - a 2,5-diphenyloxazole, optionally substituted by two groups chosen independently from linear or branched alkyl groups at C1 to C6, in particular 2,5-diphenyloxazole; and - a carbazole, optionally substituted by two groups chosen independently from linear or branched alkyls from C1 to C6, in particular 9-ethylcarbazole.

[0090] According to a particular embodiment, the composition consists of or comprises: - a biphenyl, optionally substituted by two groups chosen independently from linear or branched alkyls from C1 to C6, in particular biphenyl; - a 2,5-diphenyloxazole, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6, in particular 2,5-diphenyloxazole; - a carbazole, optionally substituted by two groups chosen independently from linear or branched alkyl groups from C1 to C6, in particular 9-ethylcarbazole; and - a diterbutylbenzene, in particular 1,4-Diterbutylbenzene, a second biphenyl, optionally substituted by two groups independently chosen from linear or branched alkyls at C1 to C6, different from the first, in particular diterbutylbiphenyl, and / or a fluorene, in particular diterbutylfluorene.

[0091] According to another aspect, the invention also relates to the use of a composition as described above as a solvent.

[0092] All embodiments defined previously with regard to the composition of the invention also apply here, alone or in combination.

[0093] According to a particular embodiment, said composition not being composed of biphenyl and naphthalene. Indeed, their binary eutectic may not have a sufficiently low melting point depending on the intended use.

[0094] These compositions, as solvents, can be used in all extraction and / or separation techniques well known to those skilled in the art involving an organic solvent. EXAMPLES

[0095] Example 1: Preparation of compositions according to the invention

[0096] The binary mixtures BA, ternary mixtures TA, and quaternary mixtures QA QB and Qc were prepared and characterized as follows.

[0097] The melting temperature of the mixtures was determined by Differential Scanning Calorimetry (DSC). Molecule Molar proportion Melting point (°C) Biphenyl 44% 69 Diphenyloxazole (PPO) 56% 70 Eutectic T CCI ba 39 Molecule Molar proportion Melting point (TA) Biphenyl 35.0% 69 9-Ethylcarbazole 37.5% 70 Diphenyloxazole (PPO) 27.5% 70 Eutectic Teutectic (°C) ta 19 Molecule Molar proportion Melting point (Tfusion) Biphenyl 31.6% 69 9-Ethylcarbazole 33.7% 70 Diphenyloxazole (PPO) 24.8% 70 Diterbutylbenzene (DTBB) 9.9% 77 Eutectic Teutectic (°C) Qa 16 Molecule Molar proportion Melting point Biphenyl 32.5% 69 9-Ethylcarbazole 34.7% 70 Diphenyloxazole (PPO) 25.6% 70 Diterbutylbiphenyl (DTBP) 7.3% 127 Eutectic t rci -1- eutectic \ '-v Qb 16 Molecule Molar proportion Melting point Biphenyl 32.6% 69 9-Ethylcarbazole 34.8% 70 Diphenyloxazole (PPO) 25.6% 70 Diterbutylfluorene (DTBF) 7.0% 123 Eutectic t rci -1- eutectic \ '-v Qc 15

[0098] Example 2: Use of the compositions according to the invention as a solvent for liquid-liquid separation

[0099] The QA mixture of Example 1 was evaluated in the extraction of a dye in aqueous phase. The dye is, for example, coumarin 151.

[0100] To do this, coumarin 151 was dissolved in water, at pH 10. The solution thus obtained is fluorescent (in the green).

[0101] During the extraction of this aqueous phase with an equal amount of toluene, only partial extraction of the dye by the toluene was visualized (green fluorescence remaining in the aqueous phase).

[0102] On the other hand, during the extraction of this same aqueous phase with the QA mixture, no residual green fluorescence was observed at the level of the extracted aqueous phase, which means a total extraction of this dye from the aqueous medium.

Claims

Demands

1. Composition consisting of or comprising at least two compounds selected from: - Di-tert-butylbenzenes; - Biphenyls and terphenyls, optionally substituted by two groups independently selected from linear or branched alkyls from C1 to C6; - Polycyclic aromatic hydrocarbons selected from naphthalenes, acenaphthenes, anthracenes, pyrenes, which are optionally substituted by two groups independently selected from linear or branched alkyls from C1 to C6; - Fluorenes and carbazoles, which are optionally substituted by two or four groups independently selected from linear or branched alkyls from C1 to C6; - 2,5-Diphenyloxazoles, optionally substituted by two groups independently selected from linear or branched alkyls from C1 to C6; - Compounds of formula (I): Ra ÆtÂ. .Rcf 1 Rc in which: i is equal to 0 or 1; Ra, Rb, Rc and Rd are independently chosen from H and phenyl, at least two of the Ra, Rb, Rc and Rd groups being phenyl; said compounds of formula (I) being optionally substituted, in particular on the phenyl groups, by two groups independently chosen from linear or branched alkyls from C1 to C6; said composition not being composed of biphenyl and naphthalene.

2.

3. A composition according to claim 1, which is eutectic. A composition according to claim 1 or 2, wherein the at least two compounds are in particular selected from the following compounds:

4.

5. in which Ri and R2 are chosen independently from one compound to another, Ri being chosen from H and linear or branched alkyls at Ci to C6, and R2 being chosen from H and linear or branched alkyls at Ci to C6. Composition according to any one of the preceding claims, which is binary, tertiary, quaternary, or quinquenar. Composition according to any one of the preceding claims, which is: - binary, and the two compounds of said composition are present in it at a level of 20 to 80 mol%, in particular at a level of 40 to 60 mol%; - tertiary, and the three compounds of said composition are present in it at a rate of 10 to 55 mol%, in particular at a rate of 25 to 40 mol%; - quaternary, and the four compounds of said composition are present therein at a level of 5 to 45 mol%, in particular at a level of 22 to 40 mol% for three of them, and at a level of 6 to 34 mol% for the last; or - quinquénaire, and the five compounds of said composition are present in it at a level of 5 to 45% molar.

6. Use of a composition as a solvent, said composition consisting of or comprising at least two compounds selected from: - Di-tert-butyl-benzenes; - Biphenyls and terphenyls, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Polycyclic aromatic hydrocarbons selected from naphthalenes, acenaphthenes, anthracenes, pyrenes, which are optionally substituted by two groups selected independently from linear or branched alkyls in QC; - Fluorenes and carbazoles, which are optionally substituted by at least two groups chosen independently from linear or branched C1 to C6 alkyls; - 2,5-Diphenyloxazoles, optionally substituted by two groups chosen independently from linear or branched alkyls at C1 to C6; - Compounds with formula (I): in which: i is equal to 0 or 1; Ra, Rb, Rc and Rd are independently chosen from H and phenyl, with at least two of the groups Ra, Rb, Rc and Rd being phenyl; said compounds of formula (I) being optionally substituted, in particular on the phenyl groups, by two groups chosen independently from linear or branched alkyls from C1 to C6.

7. Use according to claim 6, wherein said composition is devoid of another solvent, the other solvent being different from all the compounds defined in claim 1 and mixtures thereof.

8. Use according to any one of claims 6 to 7, for liquid-liquid separation, liquid-liquid-liquid separation, solid-liquid separation, or solid-liquid-liquid separation.

9. Use according to any one of claims 6 to 9, for liquid-liquid separation, one of the liquid phases being an aqueous phase, the other liquid phase comprising or consisting of said composition.

10. Use according to any one of claims 6 to 9, for the extraction of a compound, said compound being in particular selected from organic compounds and metals, the organic compounds being in particular aromatic or heteroaromatic compounds, or comprising aromatic or heteroaromatic groups, said organic compounds, in particular aromatic or heteroaromatic, or comprising aromatic or heteroaromatic groups, are for example selected from: - Phytosanitary compounds, - Organic pollutants, in particular persistent, for example dioxins, - Microplastics, - Pharmaceuticals, - Dyes, and - Carbon black.