Method for purifying eugenol and novel compositions containing eugenol

Abstract

The present invention relates to a method for purifying crude eugenol by distillation in the presence of at least one stabilizing compound. The method of the present invention can be carried out industrially, exhibits improved properties, in particular with regard to process safety, and allows for the efficient separation of ortho-eugenol. The present invention also relates to a composition containing eugenol.

Description

[Technical field]

[0001] This application claims priority to French patent application no. 1905219 filed on May 17, 2019, and to European patent application no. 19200216.0 filed on September 27, 2019, the contents of which are incorporated by reference in their entireties.

[0002] The present invention relates to a method for purifying eugenol and novel compositions containing eugenol. [Background technology]

[0003] Eugenol is the main fragrant compound of many essential oils, such as clove oil. It is frequently used in perfumery, but also exhibits antiseptic, antibacterial, analgesic, and antioxidant properties. It may also be used as a synthetic intermediate, especially in the preparation of vanillin.

[0004] In view of this widespread area of ​​application, it is necessary to produce eugenol on an industrial scale and to have optimized manufacturing processes available.

[0005] Classically, eugenol is of natural origin extracted from plants. Extraction can be carried out by steam distillation, microwave-assisted extraction or supercritical fluid extraction, among others. CN104326885 describes a method for extracting eugenol from oil, in which an aqueous phase containing the sodium salt of eugenol is produced and distilled.

[0006] Alternatively, eugenol can be obtained by a chemical process in which guaiacol is allylated in the presence of allyl chloride and a catalyst, as described in FR 2302991. Eugenol can be purified by distillation to separate it from the by-products of the reaction. CN 108383695 also describes a chemical process for preparing eugenol. This document describes a method for purifying eugenol, in which an antioxidant is added to the purified eugenol to prevent coloration of the eugenol. CN 105294409 describes an alternative synthesis process using a composite catalyst based on copper and cobalt. GB 1501221 describes another chemical process for preparing eugenol from guaiacol and allyl chloride.

[0007] When these synthesis processes are used, multiple side reactions may occur leading to the formation of ortho-eugenol or O-allylated compounds. As a result, the purification of eugenol, especially the separation of eugenol and ortho-eugenol by distillation, is complicated. This purification is further complicated because eugenol and / or ortho-eugenol exhibit undesirable properties, especially they may be explosive under the operating conditions of distillation. China Patent No. 105294409 shows a purification method in which eugenol is purified using n-octane and K2CO3, the mixture is filtered, then washed with water of K2CO3, and finally the purified eugenol is distilled from the aqueous phase.

[0008] This process presents the drawback of producing waste liquids and does not appear to be very suitable in the context of industrial application.The present invention aims in particular to produce eugenol efficiently and selectively in a manner that allows an efficient separation of eugenol and ortho-eugenol on an industrial scale under conditions of excellent safety. Summary of the Invention [Means for solving the problem]

[0009] A first subject of the present invention relates to a novel process for purifying eugenol, in which crude eugenol is distilled in the presence of at least one stabilizing compound.

[0010] The present invention also relates to a process for the separation of eugenol and ortho-eugenol by distillation in the presence of at least one stabilizing compound.

[0011] Finally, the present invention relates to a composition containing eugenol and 0.1-10000 ppm of at least one stabilizing compound, or at least one stabilizing compound and at least one auxiliary compound, wherein the stabilizing compound is selected from the group consisting of phenol derivatives, phenothiazine derivatives, TEMPO derivatives, CB, para-benzoquinone, para-phenylenediamine, diethylhydroxylamine, manganese(II) acetate, sodium nitrite, sodium ascorbate, potassium ascorbate, ergosterol, cholecalciferol, and glutathione, and the auxiliary compound is selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ). [Brief description of the drawings]

[0012] [Figure 1] 1 is a graph of a differential scanning calorimetry analysis of a sample of eugenol according to Example 1. [Diagram 2] 1 is a graph of a differential scanning calorimetry analysis of a sample of eugenol according to Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] In the context of the present invention, and unless expressly stated otherwise, the expression "between" is inclusive. Percentages and ppm are percentages and ppm by weight, unless otherwise indicated.

[0014] In the context of the present invention, and unless otherwise indicated, the term "ppm" means "parts per million". This unit represents a ratio by weight: 1 ppm = 1 mg / kg.

[0015] In the context of the present invention, and unless otherwise indicated, the term "eugenol" refers to para-eugenol or 4-allyl-2-methoxyphenol according to formula (I): [C1] TIFF0007628087000001.tif66170

[0016] In the context of the present invention, ortho-eugenol refers to 2-allyl-6-methoxyphenol according to formula (II): [Case 2] TIFF0007628087000002.tif46170

[0017] In the context of the present invention, the term "phenol derivative" refers to a compound containing a unit corresponding to formula (III): [C3] TIFF0007628087000003.tif65170

[0018] According to a particular embodiment, the term "phenol derivative" refers to a compound according to formula (IV): [C4] TIFF0007628087000004.tif49170, where R represents hydroxyl, linear or branched alkyl, preferably containing 1 to 6 carbon atoms, alkenyl, alkoxy group, preferably containing 1 to 6 carbon atoms, nitro group, or nitroso group, R2 represents linear or branched alkyl, preferably containing 1 to 6 carbon atoms, n is 0 to 5, preferably n is 0, 1, 2, or 3. Preferably, the R group is selected from the group consisting of hydroxyl, methyl, ethyl, propyl, n-butyl, t-butyl, methoxy, ethoxy, propoxy, isopropoxy, nitro, and nitroso. Preferably, the R group is selected from methyl, ethyl, propyl, n-butyl, or t-butyl.

[0019] According to an alternative form, the term "phenol derivative" refers to a compound according to formula (IV) above, in which R2 represents H and R is as defined above.

[0020] According to another particular embodiment, the phenol derivative may be chosen from compounds of the tocopherol series, in particular α-tocopherol, β-tocopherol, γ-tocopherol or δ-tocopherol.

[0021] In the context of the present invention, the term "phenothiazine derivative" refers to a compound comprising a unit according to formula (V): [5] TIFF0007628087000005.tif64170

[0022] In the context of the present invention, the term "TEMPO derivative" refers to a compound comprising a TEMPO unit according to formula (VI): [6] TIFF0007628087000006.tif64170

[0023] In particular, the term "TEMPO derivative" refers to (2,2,6,6-tetramethylpiperidin-1-yl)oxy (TEMPO), (4-hydroxy-2,2,6,6-tetramethylpiperidin-1-yl)oxy (TEMPO-OH), (4-oxo-2,2,6,6-tetramethyl-1-piperidin-1-yl)oxy (4-oxo-TEMPO), 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (4-amino-TEMPO), or bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (bishydroxyTEMPO sebacate).

[0024] In the context of the present invention, the term "stabilizer" refers to a compound capable of maintaining the qualities of a product, such as color, chemical or thermal stability, without affecting said product, in particular during production, storage or handling of the product.

[0025] In the context of the present invention, the term "crude eugenol" refers to a composition which essentially comprises eugenol, in particular containing at least 20% by weight of eugenol, preferably at least 30% by weight of eugenol, more preferentially at least 40% by weight and even more preferentially at least 50% by weight of eugenol relative to the weight of the composition. Usually, the main compound of crude eugenol is para-eugenol. In particular, crude eugenol according to the invention may contain impurities related to the synthesis process of eugenol, in particular o-eugenol, or products of O-alkylation of guaiacol or eugenol. The impurities may also originate from the starting compounds used in the reaction. Usually, the content by weight of each impurity present in the composition relative to the weight of the composition is less than the content of eugenol in the composition.

[0026] In the context of the present invention, the term "purified eugenol" refers to a composition which essentially comprises eugenol, in particular containing at least 80% by weight of eugenol, preferably at least 90% by weight of eugenol, more preferentially at least 95% by weight and even more preferentially at least 99% by weight of eugenol relative to the weight of the composition. In particular, the purified eugenol according to the invention may contain impurities linked to the synthesis process of eugenol, in particular o-eugenol, or products of the O-alkylation of guaiacol or eugenol. The impurities may also originate from the starting compounds used in the reaction. The process according to the invention makes it possible to purify crude eugenol and to obtain purified eugenol.

[0027] The crude eugenol to be purified according to the invention can be obtained by any synthetic process, which can be carried out continuously or semi-continuously in suitable reactors, such as in particular microreactors.

[0028] In a particular embodiment of the invention, eugenol is obtained from guaiacol and an allyl halide, preferentially allyl chloride, as described in French Patent No. 2302991. In particular, the alkylation reaction is carried out in the presence of an aqueous solution of an alkali metal or alkaline earth metal hydroxide, such as NaOH or KOH. Furthermore, the reaction can be carried out in the presence of a catalyst, in particular a copper-based catalyst, such as CuCl, CuCl2.2H2O, Cu(NO3)2 or Cu(OAc)2.2H2O. The reaction can also be carried out in the presence of a composite catalyst, as described in Chinese Patent No. 105294409.

[0029] Usually, the amount of catalyst is at least 0.01% by weight, preferentially at least 0.02% by weight, more preferentially at least 0.05% by weight and very preferentially at least 0.1% by weight, relative to the amount of guaiacol. Usually, the amount of catalyst is at most 10% by weight, preferentially at most 5% by weight, more preferentially at most 2% by weight and very preferentially at least 1% by weight, relative to the amount of guaiacol.

[0030] Usually, the reaction temperature is at least 5° C., preferably at least 10° C., more preferentially at least 15° C., and very preferentially at least 25° C. Usually, the reaction temperature is at most 95° C., preferably at most 80° C., more preferentially at most 65° C., and very preferentially at most 50° C.

[0031] The reaction is usually carried out in the presence of ammonium salts or ammonia, as described in patent FR 2 302 991. Ammonia can form copper-amine type complexes with the catalyst.

[0032] To suppress the formation of effluents with a high content of nitrogen derivatives, it is possible to replace the ammonia and carry out the reaction in the presence of glucose, glucosamide, citric or tartaric acid, 2-hydroxypyridine or nicotinamide.

[0033] Typically, the guaiacol salt is first formed in an aqueous solution. A catalyst is added to the reaction mixture, followed by aqueous ammonia. Finally, the allyl halide is added to the reaction mixture.

[0034] A first subject of the invention relates to a process for the purification of crude eugenol by distillation in the presence of at least one stabilizing compound.

[0035] According to another aspect, the present invention relates to a process for the purification of crude eugenol by distillation in the presence of at least one stabilizing and / or auxiliary compound.

[0036] The object of the present invention is in particular to - to provide an improved process for the production and / or purification of eugenol, in that it allows for a high productivity, - to provide an improved process for the production and / or purification of eugenol, in particular in that it makes it possible to obtain eugenol separated from the ortho-eugenol isomer, - to provide a production and / or purification process which is advantageous due to the fact that, apart from the water required to carry out the reaction, little or no aqueous effluent is produced, - to provide a production and / or purification process which can be carried out industrially in that it can be carried out under good conditions, in particular in terms of process safety, It is.

[0037] According to the present invention, the at least one stabilizing compound is selected from the group consisting of phenol derivatives, phenothiazine derivatives, TEMPO derivatives, CB (copper dibutyldithiocarbamate), para-benzoquinone, para-phenylenediamine, diethylhydroxylamine, manganese (II) acetate, sodium nitrite, sodium ascorbate, potassium ascorbate, and glutathione. According to one aspect of the present invention, the at least one stabilizing compound is selected from the above-constituted group additionally comprising bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0038] Typically, at least one stabilizing compound has a boiling point higher than the boiling point of eugenol, and preferably the boiling point of the stabilizing compound is greater than or equal to T eu +1℃ or higher, preferably T eu +5°C or higher, more preferentially T eu It is above +10℃. eu represents the boiling point of eugenol at atmospheric pressure.

[0039] According to a first particular embodiment, the at least one stabilizing compound is a compound of formula (IV) or phenothiazine (PTZ), in particular a compound selected from the group consisting of catechol, isoeugenol, hydroquinone (HQ), para-methoxyphenol (PMP), tert-butylcatechol (TBC), 2,4-dimethyl-6-(tert-butyl)phenol (topanol A), 2,4-dinitro-6-(sec-butyl)phenol, 2-methyl-4,6-dinitrophenol, para-nitrosophenol, 2-methyl-4-nitrophenol, and phenothiazine (PTZ). According to a second particular embodiment of the invention, the at least one stabilizing compound is selected from the group consisting of hydroquinone (HQ), para-methoxyphenol (PMP), tert-butylcatechol (TBC), and phenothiazine (PTZ). According to a third particular embodiment of the invention, the at least one stabilizing compound is selected from the group consisting of 2,4-dimethyl-6-(tert-butyl)phenol (Topanol A), 2,4-dinitro-6-(sec-butyl)phenol, 2-methyl-4,6-dinitrophenol, para-nitrosophenol, and 2-methyl-4-nitrophenol.

[0040] According to a fourth particular embodiment, the at least one stabilizing compound is selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT), tert-butylhydroquinone (TBHQ), di(tert-butyl)hydroxyanisole (diBHA) and di(tert-butyl)hydroquinone (diTBHQ), in particular from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ). According to another particular embodiment, the at least one stabilizing compound is selected from the group according to the first embodiment, or according to the second embodiment, or according to the third embodiment, or according to the fourth embodiment, said group additionally comprising bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0041] According to one alternative, the at least one stabilizing compound is selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), tert-butylcatechol (TBC), bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, sodium ascorbate, tert-butylhydroquinone (TBHQ), para-methoxyphenol (PMP), and glutathione.

[0042] Preferably, the purification process is carried out in the presence of a stabilizer.

[0043] According to another preferred embodiment, the purification process is carried out in the presence of two stabilizers. Preferably, the two stabilizers are selected from the group consisting of hydroquinone (HQ), para-methoxyphenol (PMP), tert-butylcatechol (TBC) and phenothiazine (PTZ). Very preferably, the process is carried out in the presence of a TBC / PMP, HQ / PMP or TBC / HQ mixture. In particular, the process can be carried out in the presence of a TBC / PMP mixture.

[0044] According to another aspect, the present invention relates to a method for purifying crude eugenol by distillation in the presence of stabilizing and auxiliary compounds.

[0045] However, without wishing to be bound by any theory, the inventors have surprisingly discovered that by adding at least one stabilizing compound during the distillation of crude eugenol, it is possible to shift the temperature zone at which thermal decomposition begins, in order to prevent the distillation process from becoming unstable, indeed even explosive. The process according to the invention can therefore be carried out under appropriate safety conditions.

[0046] According to a particular embodiment of the invention, crude eugenol is distilled in the presence of at least one auxiliary compound preferentially selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ).

[0047] Preferably, the purification process is carried out in the presence of an auxiliary compound selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ), preferably the auxiliary compound is vitamin E.

[0048] Preferably, the purification process is carried out in the presence of two auxiliary compounds selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ).

[0049] According to a particular aspect, the purification process is carried out in the presence of at least one stabilizing compound selected from the group consisting of phenol derivatives, phenothiazine derivatives, TEMPO derivatives, CB (copper dibutyldithiocarbamate), para-benzoquinone, para-phenylenediamine, diethylhydroxylamine, manganese (II) acetate, sodium nitrite, sodium ascorbate, potassium ascorbate, and glutathione, and optionally in the presence of at least one auxiliary compound selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ). According to a particular embodiment of this aspect, the at least one stabilizing compound is selected from the above group additionally comprising bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0050] According to the invention, the total amount of stabilizing compounds is at least 50 ppm, preferably at least 100 ppm, more preferentially at least 500 ppm, more preferentially at least 1000 ppm, based on the amount of eugenol. According to the invention, the total amount of stabilizing compounds is at most 10% by weight, preferably at most 5% by weight, more preferentially at most 1% by weight, more preferentially at most 5000 ppm, even more preferentially at most 2000 ppm, based on the amount of eugenol.

[0051] According to the invention, the total amount of auxiliary compounds is greater than or equal to 0 ppm, preferably greater than or equal to 100 ppm, more preferentially greater than or equal to 500 ppm, more preferentially greater than or equal to 1000 ppm, relative to the amount of eugenol. According to the invention, the total amount of auxiliary compounds is less than or equal to 5000 ppm, preferably less than or equal to 2500 ppm, more preferentially less than or equal to 2000 ppm, more preferentially less than or equal to 1000 ppm, relative to the amount of eugenol.

[0052] Advantageously, the at least one stabilizing compound can be added at the feed together with the eugenol to be purified, preferably in the distillation boiler and / or in the distillation column. The addition can be carried out in one or several portions.

[0053] According to a particular embodiment, at least one stabilizing compound is added to the distillation boiler. The at least one stabilizing compound is selected from stabilizing compounds having a boiling point higher than that of eugenol. Preferably, the boiling point of the stabilizing compound is higher than T eu +1℃ or higher, preferably T eu +5°C or higher, more preferentially T eu It is above +10℃.

[0054] According to another particular embodiment, at least one stabilizing compound is added to the distillation column. The at least one stabilizing compound can be selected from stabilizing compounds having a boiling point higher than the boiling point of eugenol. Alternatively, the at least one stabilizing compound can be selected from stabilizing compounds having a boiling point lower than or equal to the boiling point of eugenol. Preferably, the boiling point of the stabilizing compound is lower than or equal to T eu -1℃ or less, preferably T eu -5℃ or lower, more preferentially T eu It's below -10℃.

[0055] Preferably, the distillation is carried out using TBC and PMP. Preferably, the TBC is placed in a distillation boiler and the PMP is placed in a distillation column. Alternatively, the TBC and the PMP are placed in a distillation boiler.

[0056] According to the invention, the distillation is carried out at a temperature of 90° C. or more, preferably 100° C. or more, very preferentially 110° C. or more, and even more preferentially 120° C. or more. According to the invention, the distillation is carried out at a temperature of 200° C. or less, preferably 190° C. or less, very preferentially 180° C. or less, and even more preferentially 150° C. According to the invention, the distillation is carried out at a pressure of 0.5 mbar or more, preferably 1 mbar or more, more preferentially 5 mbar or more, and even more preferentially 10 mbar or more. According to the invention, the distillation is carried out at a pressure of 150 mbar or less, preferably 100 mbar or less, and even more preferentially 50 mbar or less.

[0057] According to a particular embodiment, the distillation also allows the separation of excess guaiacol, eugenol and / or products of O-alkylation of guaiacol, as well as ortho-eugenol. The guaiacol used for the preparation of eugenol may also contain certain impurities, such as veratrole or 6-methylguaiacol, and the reaction mixture obtained at the end of the allylation reaction may also contain products of allylation of said impurities, in particular allylveratrol or 4-allyl-6-methylguaiacol. The reaction mixture obtained at the end of the allylation reaction may also contain isomerization products of the allyl group, in particular isoeugenol or meta-eugenol (also known as 2-methoxy-5-(prop-2-en-1-yl)phenol).

[0058] The invention also relates to a method which in particular allows the separation of eugenol and ortho-eugenol. In particular, the eugenol obtained at the end of the distillation is purified eugenol. In particular, the eugenol obtained at the end of the distillation comprises ortho-eugenol in an amount of less than or equal to 10% by weight, in particular less than or equal to 5% by weight, preferentially less than or equal to 2.5% by weight and more preferentially less than or equal to 1% by weight relative to the total weight of the composition. According to the invention, the eugenol obtained at the end of the distillation comprises ortho-eugenol in an amount greater than or equal to 0.01% by weight, preferentially greater than or equal to 0.05% by weight and even more preferentially greater than or equal to 0.1% by weight relative to the total weight of the composition.

[0059] The process according to the invention makes it possible in particular to separate eugenol and guaiacol.

[0060] Advantageously, the process according to the invention allows the preparation of eugenol with satisfactory organoleptic properties, in particular the eugenol obtained according to the process of the invention exhibits organoleptic properties similar to those of eugenol obtained by extraction of natural products.

[0061] The present invention relates to a process for the preparation of eugenol comprising a purification process as defined above.

[0062] The process for the preparation of eugenol usually comprises a step of preparing crude eugenol, which can in particular be carried out by allylation of guaiacol, as described in particular in patent FR 2 302 991.

[0063] The process for the preparation of eugenol comprises a second step in which the crude eugenol is purified by a purification process by distillation in the presence of at least one stabilizing compound.

[0064] The present invention also relates to the use of the above-described process for purifying crude eugenol for separating eugenol and ortho-eugenol.

[0065] In another aspect, the present invention relates to the use of a stabilizing compound for stabilizing a eugenol purification process.

[0066] Finally, the present invention relates to a composition containing eugenol and 0.1-10000 ppm of at least one stabilizing compound or at least one stabilizing compound and at least one auxiliary compound, wherein the stabilizing compound is selected from the group consisting of phenol derivatives, phenothiazine derivatives, TEMPO derivatives, CB (copper dibutyldithiocarbamate), para-benzoquinone, para-phenylenediamine, diethylhydroxylamine, manganese (II) acetate, sodium nitrite, sodium ascorbate, potassium ascorbate, and glutathione, and the auxiliary compound is selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ). In a particular embodiment, the above composition additionally contains bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0067] According to the invention, the total amount of stabilizing compounds in the composition is at least 0.1 ppm, preferably at least 1 ppm, more preferentially at least 10 ppm, more preferentially at least 100 ppm, relative to the amount of eugenol. According to the invention, the total amount of stabilizing compounds is at most 10000 ppm, preferably at most 5000 ppm, more preferentially at most 2000 ppm, more preferentially at most 1000 ppm, even more preferentially at most 500 ppm, relative to the amount of eugenol.

[0068] According to the invention, the total amount of auxiliary compounds is greater than or equal to 0 ppm, preferably greater than or equal to 0.1 ppm, more preferentially greater than or equal to 1 ppm, more preferentially greater than or equal to 10 ppm, relative to the amount of eugenol. According to the invention, the total amount of auxiliary compounds is less than or equal to 5000 ppm, preferably less than or equal to 2500 ppm, more preferentially less than or equal to 2000 ppm, more preferentially less than or equal to 1000 ppm, relative to the amount of eugenol.

[0069] According to a particular embodiment, the at least one stabilizing compound is a compound of formula (IV) or a phenothiazine (PTZ), in particular catechol, isoeugenol, hydroquinone (HQ), para-methoxyphenol (PMP), tert-butylcatechol (TBC), di(tert-butyl)hydroxyanisole (diBHA), di(tert-butyl)hydroquinone (diTBHQ), 2,4-dimethyl-6-(tert-butyl)phenol (topanole A), 2,4-dinitro-6-(sec-butyl )phenol, 2-methyl-4,6-dinitrophenol, para-nitrosophenol, 2-methyl-4-nitrophenol and phenothiazine (PTZ), more preferentially from the group consisting of hydroquinone (HQ), para-methoxyphenol (PMP), tert-butylcatechol (TBC), phenothiazine (PTZ), di(tert-butyl)hydroxyanisole (diBHA) and di(tert-butyl)hydroquinone (diTBHQ). According to one alternative, the at least one stabilizing compound is in particular selected from the group constituted above, additionally comprising a compound of formula (IV) or phenothiazine (PTZ), in particular bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

[0070] According to a particular embodiment, the composition according to the invention comprises a stabilizing compound.

[0071] According to another particular embodiment, the composition according to the invention comprises two stabilizing compounds.

[0072] According to another particular embodiment, the composition according to the invention contains at least one stabilizing compound selected from the group consisting of hydroquinone (HQ), para-methoxyphenol (PMP), tert-butylcatechol (TBC) and phenothiazine (PTZ) and at least one auxiliary compound selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ).

[0073] According to another particular embodiment, the composition according to the invention contains at least one stabilizing compound selected from the group consisting of 2,4-dimethyl-6-(tert-butyl)phenol (Topanol A), 2,4-dinitro-6-(sec-butyl)phenol, 2-methyl-4,6-dinitrophenol, para-nitrosophenol and 2-methyl-4-nitrophenol, and at least one auxiliary compound selected from the group consisting of vitamin E, butylated hydroxyanisole (BHA), dibutylated hydroxytoluene (BHT) and tert-butylhydroquinone (TBHQ).

[0074] According to a particular embodiment, the composition according to the invention contains at least 90% by weight of eugenol, preferably at least 95% by weight of eugenol, more preferentially at least 99% by weight, more preferentially at least 99.5% by weight and even more preferentially at least 99.95% by weight of eugenol relative to the total weight of the composition.

[0075] According to another particular embodiment, the content of ortho-eugenol in the composition is less than or equal to 10% by weight, preferably less than or equal to 8% by weight, very preferentially less than or equal to 5% by weight and even more preferentially less than or equal to 1% by weight relative to the weight of the composition.

[0076] According to a particular embodiment, the eugenol / o-eugenol ratio is greater than or equal to 90:10, preferably greater than or equal to 95:5 and very preferentially greater than or equal to 99:1.

[0077] According to another particular embodiment, the content of isoeugenol in the composition is less than or equal to 5% by weight, preferably less than or equal to 2% by weight, very preferentially less than or equal to 1% by weight and even more preferentially less than or equal to 0.5% by weight relative to the weight of the composition.

[0078] Finally, the present invention relates to a composition containing at least 90% by weight of eugenol and at most 10% by weight of ortho-eugenol relative to the total weight of the composition.Preferably, the composition contains at least 95% by weight of eugenol, more preferentially at least 99% by weight, even more preferentially at least 99.5% by weight of eugenol relative to the total weight of the composition.Preferably, the content of ortho-eugenol in the composition is less than or equal to 10% by weight, preferably less than or equal to 8% by weight, very preferentially less than or equal to 5% by weight, even more preferentially less than or equal to 1% by weight relative to the weight of the composition.

[0079] Advantageously, the inventors have discovered that compositions according to the present invention exhibit satisfactory organoleptic properties. In particular, the compositions according to the invention exhibit organoleptic properties that are similar or at least equivalent to those of eugenol obtained by extraction of natural products.

[0080] Advantageously, the compositions according to the invention can be used in perfume or fragrance, analgesic, antibacterial or antioxidant compositions. Advantageously, the compositions according to the invention exhibit properties, in particular with regard to organoleptic properties, that make them suitable for their use in perfume or fragrance, analgesic, antibacterial or antioxidant compositions.

[0081] The following examples are intended to illustrate the invention but not to limit it. To the extent that the disclosures of the patents, patent applications, and publications cited herein by reference contradict the description of this patent application to the extent that there is a risk of rendering the term uncertain, this description shall control. EXAMPLES

[0082] Examples 1 (invention) and 2 (comparison): Differential scanning calorimetry test Differential scanning calorimetry studies are carried out with eugenol in the presence (Example 1) or in the absence (Comparative-Example 2) of a stabilizing compound.

[0083] TIFF0007628087000007.tif49170

[0084] Differential scanning calorimetry performed on a Mettler Toledo DSC calorimeter; samples are placed in gold crucibles and heated continuously from 25° C. to 400° C. at a rate of 2° C. / min under nitrogen flow (50 ml / min).

[0085] Figure 2 shows that without stabilizing compounds, the thermal decomposition of eugenol begins at 110° C. Figure 1 shows that in the presence of stabilizing compounds, the thermal decomposition of eugenol begins at above 270° C., resulting in the possibility of carrying out the distillation process under appropriate safety conditions.

[0086] Examples 3 (comparison) and 4-11 (invention): Differential scanning calorimetry studies Differential scanning calorimetry studies are carried out according to Examples 1 and 2 using commercial eugenol from different batches in the presence (Examples 4-11) or absence (Comparative-Example 3) of stabilizing compounds. The stabilizing compounds tested are TBC (Example 4), Vitamin E (Example 5), Bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate (Example 6), Sodium Ascorbate (Example 7), BHA (Example 8), TBHQ (Example 9), Glutathione (Example 10), and PMP (Example 11).

[0087] TIFF0007628087000008.tif60170

[0088] Table 2 shows that in the absence of stabilizing compounds, the thermal decomposition of eugenol begins at 275° C. and releases 398 J / g. Examples 2-9 show that in the presence of stabilizing compounds, the thermal decomposition of eugenol begins at 285° C. or higher and releases significantly less energy, resulting in the ability to carry out the distillation process under appropriate safety conditions.

Claims

1. A method for purifying crude eugenol containing eugenol and impurities, comprising the steps of: distilling crude eugenol in the presence of at least one stabilizing compound, the stabilizing compound is selected from the group consisting of phenol derivatives, phenothiazine derivatives, TEMPO derivatives, CB (copper dibutyldithiocarbamate), para-benzoquinone, para-phenylenediamine, diethylhydroxylamine, manganese(II) acetate, sodium nitrite, sodium ascorbate, potassium ascorbate, and glutathione; The phenol derivative is a compound according to formula (IV): (In the formula, R represents hydroxyl, a linear or branched alkyl, alkenyl, alkoxy group, a nitro group, or a nitroso group; R ２ represents a linear or branched alkyl group; n is 0 to 5); The phenothiazine derivative is a compound comprising a unit according to the following formula (V): The TEMPO derivative is a compound comprising a TEMPO unit according to the following formula (VI): method.

2. 2. The method of claim 1, wherein the at least one stabilizing compound has a boiling point higher than the boiling point of eugenol.

3. 3. The method according to claim 1 or 2, wherein the total amount of stabilizing compounds is between 50 ppm and 10% by weight relative to the amount of eugenol.

4. The method according to claim 1, wherein the stabilizing compound is bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

5. 5. The method of claim 1, wherein the crude eugenol further comprises ortho-eugenol, and wherein eugenol is separated from ortho-eugenol.

6. 1. A method for purifying crude eugenol containing eugenol and ortho-eugenol, comprising the steps of: separating eugenol and ortho-eugenol by distillation in the presence of at least one stabilizing compound; the stabilizing compound is selected from the group consisting of phenol derivatives, phenothiazine derivatives, TEMPO derivatives, CB (copper dibutyldithiocarbamate), para-benzoquinone, para-phenylenediamine, diethylhydroxylamine, manganese(II) acetate, sodium nitrite, sodium ascorbate, potassium ascorbate, and glutathione; The phenol derivative is a compound according to formula (IV): (In the formula, R represents hydroxyl, a linear or branched alkyl, alkenyl, alkoxy group, a nitro group, or a nitroso group; R ２ represents a linear or branched alkyl group; n is 0 to 5); The phenothiazine derivative is a compound comprising a unit according to the following formula (V): The TEMPO derivative is a compound comprising a TEMPO unit according to the following formula (VI): method.

7. The method of claim 6, wherein the stabilizing compound is bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate.

8. 1. A method for producing a purified eugenol composition, comprising the steps of: A method comprising purifying crude eugenol by the method according to any one of claims 1 to 6 to obtain a purified eugenol composition.

9. 9. The method according to claim 8, wherein the content of ortho-eugenol in the purified eugenol composition is 10% by weight or less, based on the total weight of the purified eugenol composition.

10. The method of claim 1 or 6, wherein the straight chain or branched alkyl represented by R contains from 1 to 6 carbon atoms.

11. The method of claim 1 or 6, wherein the alkoxy group contains 1 to 6 carbon atoms.

12. R ２ The method of claim 1 or 6, wherein the linear or branched alkyl of the formula:

13. The method of claim 1 or 6, wherein n is 0, 1, 2, or 3.

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