Process for preparing polythiol compositions and terpenes or terpene derivatives thereof

Abstract

The present invention relates to a process for preparing polythiols from terpenes or terpene derivatives, as well as to polythiol compositions and novel polythiols. The process is a) A step of reacting a terpene or terpene derivative with a thiocarboxylic acid in the presence of oxygen (O2) and at least one organic solvent to obtain a reaction medium containing a polythioester and the at least one organic solvent, and b) A step to obtain a polythiol by carrying out a deprotection step of the polythioester obtained in step a). Includes, Steps a) and b) are performed in one-pot synthesis.

Description

[Technical Field]

[0001] The present invention relates to a process for preparing a polythiol composition using a terpene or terpene derivative as a starting reaction product, and to a polythiol composition obtained by this process. [Background technology]

[0002] Polythiols are industrially important molecules. They are used, for example, as crosslinking agents, especially at low temperatures.

[0003] Currently, several synthetic routes exist for obtaining polythiols. Among the most widely used methods is the reaction between a polyol and a mercaptoic acid (for example, described in U.S. Patent Application No. 2005 / 0153231). This reaction is straightforward and allows for the acquisition of various polythiol structures, but the resulting product generally has low resistance to hydrolysis due to the presence of many ester groups.

[0004] Alternatively, molecules without hydrolyzable functional groups can be obtained by the direct addition of hydrogen sulfide to the polyene using an acid or photocatalyst. This additive is described in particular in International Publication No. 2012 / 018757. However, this method may produce a large amount of sulfide compounds as byproducts, and conversion rate problems may arise depending on the reactants used. Consequently, the resulting molecules may contain many unreacted double bonds, which leads to stability problems and reduces the overall content of -SH groups. For example, if the starting reactants are of the triene type, this is particularly reflected in the presence of a large amount of monothiols and / or dithiols in the resulting composition.

[0005] In fact, controlling and / or reducing the formation of these by-products, such as monothiols and / or dithiols, is important depending on the intended application. This is because their content affects the degree of crosslinking of the subsequently prepared material, particularly thermosetting materials produced from resins and polythiol-type curing agents. Consequently, the degree of crosslinking has been shown to affect the physical properties and viscoelastic characteristics of the polymer, such as polymer density, elastic modulus, elastic limit, or glass transition temperature (Tg). Tg is conventionally determined by differential scanning calorimetry (DSC) or dynamic mechanical analysis (DM(T)A).

[0006] These parameters directly relate to the behavior of materials, such as hardness, elasticity, flexibility, or tear strength. In particular, to obtain materials with higher heat resistance (i.e., those that retain their properties over a wider temperature range), it is desirable to obtain polymers with high glass transition temperatures.

[0007] Therefore, there is a need for industrial preparation processes for polythiols that can control, and even maximize, the conversion of the C=C double bond to the -SH group. There is also a need for preparation processes for polythiols that can control, and even reduce, the formation of by-products (e.g., monothiols and / or dithiols in the case of trithiols or sulfides).

[0008] One technical solution involves using a polythioester intermediate. That is, the C=C double bond is converted to an R'-C(O)-SR” type functional group, which is then deprotected to obtain the desired polythiol. However, these polythioester intermediates are technically difficult to use industrially. They are generally very viscous compounds, and in fact even solid. Therefore, they are difficult to handle for the deprotection process. Thus, they present many practical problems at an industrial level and are rarely used in practice.

[0009] Furthermore, these polythioesters are conventionally obtained by the reaction of polyenes with thiocarboxylic acids, particularly thioacetic acid. However, this reaction involves the use of a large excess of thiocarboxylic acid that must be removed before the deprotection step. Therefore, in order to carry out the subsequent deprotection step, a further step of evaporation of this excess thiocarboxylic acid and / or purification of the polythioester is required.

[0010] Finally, the reactants used in this type of process are generally petroleum-derived hydrocarbons. Given current environmental and climate challenges, processes using bio-based and / or renewable starting materials are preferable.

[0011] Therefore, an improved process is needed for the preparation of polythiols via polythioesters. Improved processes are also needed for the preparation of polythiols from bio-derived and / or renewable starting materials. A polythiol composition is needed in which the -SH group content is controlled, and in fact even maximized. The term "-SH group content" is understood to mean the ratio of the total weight of -SH groups to the total weight of the composition. Polythiol compositions obtained from bio-derived and / or renewable starting materials are also required. [Overview of the project] [Problems that the invention aims to solve]

[0012] The object of the present invention is to provide an improved process for the preparation of polythiol compositions from terpenes or terpene derivatives, which simplifies industrial implementation. The object of the present invention is to provide an improved process for preparing polythiol compositions from terpenes or terpene derivatives in which the -SH group content is controlled, and in fact even maximized. Another object of the present invention is to provide an improved polythiol composition in which the content of -SH groups is controlled, and in fact even maximized. An object of the present invention is also to provide polythiol compositions obtained from biologically derived starting materials and / or renewable starting materials, namely terpenes and terpene derivatives. The object of the present invention is to provide a polythiol composition used for the preparation of polymers, preferably thermosetting polymers. [Means for solving the problem]

[0013] The present invention addresses the above objectives, either in whole or in part. [Brief explanation of the drawing]

[0014] [Figure 1] myrcene isomers [Modes for carrying out the invention]

[0015] The inventors have surprisingly discovered that a “one-pot” process can be employed to synthesize polythiols from terpenes or terpene derivatives. The term “one-pot process” is understood to mean a process in which the reaction intermediate (i.e., a polythioester as described herein) is not isolated from the reaction medium in order to carry out subsequent deprotection steps. Such a one-pot process offers many advantages in the context of the industrial synthesis of polythiols.

[0016] In particular, the polythioester intermediate formation step (hereinafter referred to as step a)) according to the present invention allows for the acquisition of a very good conversion rate (especially a 90% to 100% conversion rate for terpenes or terpene derivatives) while avoiding the excessive use of thiocarboxylic acid. In fact, in conventional processes, a large excess of thiocarboxylic acid is used, which not only reduces process efficiency but also generates a large amount of waste requiring separation and treatment. Furthermore, since such excess amounts must be removed before the deprotection step, it is difficult to achieve compatibility with a "one-pot" process. The present invention makes it possible to avoid these drawbacks and brings not only economic advantages but also environmental advantages.

[0017] Another advantage of the present invention is that the reaction medium containing the polythioester intermediate obtained at the end of step a) can be easily stirred and handled. This can take the form, in particular, of a viscous or slightly viscous liquid or suspension. Thus, operational difficulties at the industrial level are avoided. The reaction medium containing the polythioester intermediate is also compatible with the deprotection step (hereinafter step b)), thereby simplifying the process. Thus, steps a) and b) according to the present invention are carried out as a "one-pot" reaction. Thus, intermediate steps for removing excess thiocarboxylic acid and / or purifying the polythioester intermediate, such as extraction, recrystallization and / or distillation, are not required, and the process is significantly improved.

[0018] Furthermore, terpenes and their derivatives may be particularly useful as starting polyenes leading to polythiols. Terpenes and derivatives address many current environmental and climate-related issues. They are generally of biological origin, i.e., derived from renewable organic matter (biomass) from plants or animals. They also exhibit a very diverse structure, enabling a very diverse range of applications.

[0019] The polythiol compositions obtained by the process of the present invention are novel and are characterized by a controlled -SH content, which may in some cases be maximized. They are particularly characterized by a high weight ratio as defined below

Number

[0020] Therefore, the present invention relates to a process for preparing polythiols, comprising the following steps. a) A step of reacting a terpene or terpene derivative with a thiocarboxylic acid in the presence of oxygen (O2) and at least one organic solvent to obtain a reaction medium containing a polythioester and the at least one organic solvent, and b) A step of obtaining a polythiol by carrying out a deprotection step of the polythioester obtained in step a). Steps a) and b) are performed using a one-pot synthesis method.

[0021] The present invention relates to a polythiol composition A obtained from a terpene or terpene derivative having x C=C double bonds, wherein the composition is - A polythiol corresponding to the terpene or terpene derivative containing x -SH groups, and - A thiol corresponding to the terpene or terpene derivative, comprising (x-1) -SH groups, where x is an integer of 3 or more, preferably by weight ratio

number

[0022] The present invention also relates to a polythiol selected from trithiol obtained from dihydrofarnesene, heptatiol obtained from isosqualene, and tetrathiol obtained from camphorene.

[0023] The term "alkyl" is understood to mean, in particular, a linear, branched, or cyclic saturated hydrocarbon radical containing 1 to 10, preferably 1 to 4, carbon atoms. The term "aryl" is understood to mean a cyclic (monocyclic, bicyclic, or tricyclic) aromatic hydrocarbon radical, particularly containing 6 to 10 carbon atoms, preferably phenyl or naphthyl, more preferably phenyl. The term "aralkyl" is understood to mean alkyl groups that are substituted with aryl, for example, benzyl.

[0024] Terpenes The term "terpene" specifically refers to the isoprene repeating unit (C5C8). n It is understood to mean a linear, branched, or cyclic hydrocarbon compound consisting of a terpene, where n is an integer from 2 to 8, preferably from 2 to 6. In particular, the terpene contains at least three C=C double bonds. Preferably, the terpene contains three, four, five, or six C=C double bonds. Terpenes are often commercially available in the form of compositions containing isomers, and the proportions of these isomers can vary (particularly depending on the process by which they are obtained). Such compositions are within the scope of the present invention and can be used directly as starting reaction products. The terpene family has traditionally been classified according to the value of n (corresponding number of carbon atoms) as shown in the table below. [Table 1] In particular, terpenes are selected from monoterpenes, triterpenes, and sesquiterpenes. More specifically, terpenes are selected from linear terpenes or branched terpenes. Among the preferred terpenes, myrcene and farnesene can be mentioned.

[0025] Milsen Myrcene is a monoterpene. Myrcene has various isomers, including ocimene and allocimene. In particular, α-myrcene, β-myrcene, cis-α-ocimene, trans-α-ocimene, cis-β-ocimene, trans-β-ocimene, 4-cis-6-cis-alloocimene, 4-cis-6-trans-alloocimene, 4-trans-6-cis-alloocimene, and 4-trans-6-trans-alloocimene (see Figure 1). Preferably, β-myrcene, the natural form (CAS number 123-35-3) of the following formula, is used. [Chemical formula 1] [ka]

[0026] Farnesen Farnesene is a sesquiterpene. It exists in two isomers, namely α-farnesene (CAS number 502-61-4) and β-farnesene (CAS number 502-60-3), as shown in the following formulas. [Chemical formula 2] [ka] More specifically, examples include cis-α-farnesene, trans-α-farnesene, cis-β-farnesene, and trans-β-farnesene. β-farnesene is preferred, and trans-β-farnesene (CAS number 18794-84-8) is even more preferred.

[0027] Other terpenes that can be used include humulene (CAS 6753-98-6), elemene, germacrene, bisabolene, sembrene, casben, zingiberene, camphorene, and their isomers. In particular, the following isomers can be used: α-elemene, β-elemene, γ-elemene, δ-elemene, germacrene A, germacrene B, germacrene C, germacrene D, germacrene E, α-bisabolene, β-bisabolene, and γ-bisabolene.

[0028] Terpene derivatives The term "terpene derivative" is understood to mean, in particular, a compound whose structure is derived from that of a terpene. They may arise from the chemical transformation of terpenes or may exist naturally. In particular, the terpene derivative contains at least three C=C double bonds, for example, 3 to 10 C=C double bonds. The following terpene derivatives can be listed.

[0029] Hydrogenated derivatives of terpenes or hydrogenated terpenes The term "hydrogenated derivative of terpene" is understood to mean, in particular, a compound of the empirical formula (C 5n H 8n+2z ), where z is an integer equal to at least 1 and n is as defined above. Preferably, z is from 1 to 10, more preferably from 1 to 3. Among the hydrogenated derivatives, squalene and dihydrofarnesene are particularly preferred.

[0030] Squalene (CAS No. 111 - 02 - 4) has the following formula.

Chemical formula

[0031] Dihydrofarnesene has the empirical formula C 15 H 26 . This can exist in different isomeric forms depending on the double bonds of the hydrogenated farnesene and the α or β isomers of the selected farnesene. Dihydro - β - farnesene (and all of its isomers) is preferred. More specifically, the following isomers of dihydrofarnesene can be used according to the present invention. [Chemical formula 3]

Chemical formula

Chemical formula

Chemical formula

[0032] When partially hydrogenating farnesene (C 15 H 24 ), dihydrofarnesene and tetrahydrofarnesene (C 15 H28 ) and hexahydrofarnesene (C 15 H 30 It is also possible to obtain a composition comprising one or more other partially hydrogenated compounds selected from ). Such a composition can be used as a starting reactant in the context of the present invention. The dihydrofarnesene contained in the composition produces the corresponding trithiol according to the process of the present invention. Preferably, such a composition contains at least 70% by weight of dihydrofarnesene, more preferably at least 80% by weight of dihydrofarnesene, based on the total weight of the composition. Preferably, the composition contains at least 85% by weight of dihydrofarnesene, based on the total weight of unreacted farnesene, all partially hydrogenated compounds resulting from farnesene, and farnesene present in the composition. In this type of composition, it is particularly preferable to use a β-isomer of farnesene to obtain dihydro-β-farnesene.

[0033] Therefore, in preference, it can be mentioned that Myralene 10 (trademark) (CAS number 1581740-29-5), compositions obtained from the partial hydrogenation of β-farnesene, and the process for their preparation are described in International Patent Application Publication No. 2016 / 064853. Myralene 10 (trademark) mainly comprises dihydro-β-farnesene. Such compositions are perfectly suitable as starting reaction products according to the present invention.

[0034] Terpenoids The term "terpenoid" is understood to mean, in particular, a compound whose structure is derived from a terpene and which optionally contains one or more heteroatoms (especially oxygen and / or nitrogen, preferably oxygen) and / or one or more chemical groups. For example, a terpenoid may contain at least one group selected from alcohol, ketone, ether, ester, or aldehyde groups. These are, in particular, the composition formula (C 5n H 8n-2y ) can be such that n is defined above and y is an integer from 1 to 4. Preferably, terpenoids are Cosmen, β-carotene, lycopene, farnesol, retinol, retinal, vitamin A, nerolidol, isomylsenol and ipsdienol, It is selected from the group consisting of the following.

[0035] Terpenes and / or hydrogenated terpene derivatives and / or terpenoid oligomers The term "oligomer" specifically refers to an aggregate of 2 to 10 terpenes and / or hydrogenated terpene derivatives and / or terpenoids as defined above, which are identical or different, preferably identical. Preferably, terpene and / or terpenoid dimers and / or trimers are used. More preferably, terpene dimers are used.

[0036] More specifically, isosqualene, a dimer of β-farnesene (composition formula C) as shown below. 30 H 48 (For example, as described in U.S. Published Patent No. 2011 / 0287988) [Chemical formula 6] [ka] The following isomers of isosqualene can also be used in accordance with the present invention. [Chemical formula 7] [ka] [Chemical formula 8] [ka] [Chemical formula 9] [ka]

[0037] Therefore, the term "terpenes and terpene derivatives" is preferred to be used. It is understood to mean terpenes, hydrogenated terpene derivatives, terpenoids, and oligomers of terpenes and / or oligomers of hydrogenated terpenes and / or oligomers of terpenoids. Therefore, the terpene or terpene derivative is The group can be selected from myrcene, farnesene, humulene, elemen, germacrene, bisabolene, cosmen, sembren, casuben, zingiberene, β-carotene, lycopene, camphorene, squalene, isosqualene, dihydrofarnesene, farnesol, retinol, retinal, vitamin A, nerolidol, isomilcenol, and ipsdienol. More preferably, the terpene or terpene derivative is selected from the group consisting of myrcene, farnesene, squalene, isosqualene, humulene, and dihydrofarnesene. Such starting materials are naturally occurring in plants and marine species, or can be produced by fermentation, using genetically modified or non-genetically modified organisms, and, if applicable, renewable carbon sources. They are also commercially available. For example, Amyris sells trans-β-farnesene under the name Biofene®, and DRT sells myrcene.

[0038] Polythiol According to the present invention, the term "polythiol" refers to a polythiol corresponding to the starting terpene or starting terpene derivative defined above. The term "corresponding to a starting terpene or starting terpene derivative" is understood to mean that the structure of the starting terpene or starting terpene derivative and the resulting polythiol are identical, except for the C=C double bond converted to an -SH group (i.e., -CH-C(SH)-). For x C=C double bonds in the starting terpene or starting terpene derivative, x -SH groups are obtained. Polythiols, which are positional isomers of the double bond, are also included in the term "polythiol". Therefore, the number of C=C double bonds contained in the terpene or terpene derivative is hereinafter referred to as "x", where x is preferably an integer of 3 or more. Preferably, x is 3 to 10, more preferably 3 to 7. The polythiol according to the present invention may also be referred to as (x)thiol, where x is as defined above.

[0039] Polythioester intermediates The terms “polythioester intermediate” or “polythioester” are understood to mean the polythioester corresponding to the starting terpene or starting terpene derivative. The term “corresponding to the starting terpene or starting terpene derivative” is understood to mean that the structure of the starting terpene or starting terpene derivative and the resulting polythioester are identical, except that the C=C double bond is converted to a -CH-C(O)-S-R1 group (where R1 depends on the thiocarboxylic acid used, and preferably R1 is methyl). For x C=C double bonds, x thioester groups are obtained, where x is as defined above. The term “polythioester” also includes polythioesters that are positional isomers of the double bond of the starting terpene or terpene derivative.

[0040] Process according to the present invention Process a) During step a), the terpene or terpene derivative defined above is reacted with a thiocarboxylic acid in the presence of oxygen (O2) and at least one organic solvent to obtain a reaction medium containing the polythioester defined above and the at least one organic solvent. The reaction is as follows: R-CH=CH-R+R1-C(O)-SH → R-CH2-CH(SC(O)-R1)-R

[0041] Step a) is carried out in the presence of oxygen (O2), which acts as a reaction initiator. Therefore, step a) can be carried out in the presence of air, dilute air (a mixture of oxygen and nitrogen N2), or a mixture of oxygen and another inert gas. Oxygen can be introduced into the reaction medium by any technique. Oxygen may or may not be added throughout step a). In particular, oxygen is preferably blown into the reaction medium in the form of dilute air. For example, the dilute air passes through a frit or diffuser immersed in the reaction medium. Alternatively, oxygen can be bubbling into the reaction medium and nitrogen can be introduced into the gas phase of the reactor (i.e., the reactor headspace). The oxygen flow rate may be 0.01 to 100 Sl / h, preferably 0.05 to 10 Sl / h, more preferably 0.05 to 5 Sl / h, and particularly 0.05 to 2 Sl / h (standard liters / h). Step a) is carried out in the absence of any other reaction initiators, and more preferably in the absence of AIBN (azobisisobutyronitrile) and / or ultraviolet light.

[0042] Step a) is also carried out in the presence of an organic solvent or a mixture of organic solvents. A polar solvent or a mixture of polar solvents is particularly preferred. The solvent may be a polar protic solvent or a polar aprotic solvent. Among the usable solvents are alcohols, ethers (preferably cyclic ethers and glycol ethers, e.g., glycol dialkyl ethers), organochlorinating solvents, carboxylic acids, or mixtures thereof. Alcohols of the following general formula (IV) are particularly preferred. R4-OH (IV) In the formula, R4 represents an alkyl group as defined above. Preferably, the alcohol is selected from the group consisting of methanol, ethanol, isopropanol, n-propanol, n-butanol, butan-2-ol, isobutanol, and tert-butanol, and more preferably ethanol. Preferably, the solvent is selected from the group consisting of tetrahydrofuran (THF), 2-methyltetrahydrofuran (Me-THF), dioxane, chloroform, acetic acid, methanol, ethanol, isopropanol, n-propanol, n-butanol, butan-2-ol, isobutanol, tert-butanol, dimethoxyethane (also called grimm), diethoxyethane, dibutoxyethane, and mixtures thereof, with ethanol being more preferred.

[0043] The amount of solvent used is generally selected according to the desired viscosity of the reaction medium. Complete or partial dissolution can be achieved by those skilled in the art, depending on the target viscosity of the reaction medium. Preferably, 1 to 50 molar equivalents, more preferably 1 to 20 molar equivalents, of solvent is used relative to the terpene or terpene derivative. The solvent can be added completely or partially from the beginning of step a). During step a), it may be added all at once, in multiple steps (semi-continuously), or in stages (continuously).

[0044] Thiocarboxylic acids are preferably represented by the following general formula (II). R1-C(O)-SH (II) During the ceremony, R1 represents an alkyl radical, aryl radical, or aralkyl radical as defined above. Preferably, R1 is selected from methyl, ethyl, and benzyl. Thioacetic acid in which R1 is methyl is very particularly preferred according to the present invention (hereinafter also referred to as ATA). For example, when thioacetic acid is used, polythioacetate is obtained as a polythioester intermediate.

[0045] According to one embodiment, thiocarboxylic acids can be produced in situ (see U.S. Patent No. 3,270,063, Thompson Chemical Co., 1963, “Methods of Making Primary Mercaptans”), and thioacetic acid can be produced from acetic anhydride and hydrogen sulfide in the presence of a catalyst. Preferably, in order to carry out step a), the thiocarboxylic acid and solvent are first introduced into the reactor, and then oxygen is introduced, for example, by bubbling air. After that, the terpene or derivative can be added to the reaction medium. The temperature in step a) may be 5°C to 80°C, preferably 5°C to 50°C, more specifically 5°C to 25°C, for example 5°C to 10°C. Step a) is generally carried out at atmospheric pressure. The molar ratio of thiocarboxylic acid to double bond in a terpene or terpene derivative may be 1 to 20, preferably 1 to 10, for example 1 to 5, and more preferably 1 to 3.

[0046] By step a), the polythioester intermediate defined above can be formed starting from a terpene or terpene derivative. Therefore, the reaction medium obtained at the end of step a) may include the following: - The polythioester intermediate defined above, - The solvent or mixture of solvents as defined above, - By-products, such as (x-1) polythioesters, and - Cases where there are one or more unreacted reactants. The term "(x-1) polythioester" is understood to mean a compound containing x-1 thioester groups, where x is as defined above. This is a compound that retains a C=C double bond (i.e., an unreacted C=C double bond). Therefore, the reaction medium may contain 10% to 85% by weight of the polythioester intermediate relative to the total reaction medium. The reaction medium may contain 15% to 90% by weight of the solvent relative to the total amount of the reaction medium.

[0047] Step b) A polythiol can be obtained by deprotecting the polythioester intermediate obtained in step a) in step b). This can be done by any means known to those skilled in the art. Since steps a) and b) are carried out in a one-pot synthesis according to the present invention, it is understood that the reaction medium containing the polythioester obtained at the end of step a) is retained for carrying out the deprotection step b). Thus, steps a) and b) are carried out in the presence of the same solvent (or solvent mixture). The solvent (or solvent mixture) can be further added during step b). In particular, the process according to the present invention does not include a step of separation and / or extraction and / or washing of the (organic) phase containing the polythioester between steps a) and b). In particular, there is no intermediate step of purification of the polythioester. More specifically, there is no step of recrystallization and / or distillation of the polythioester.

[0048] Deprotection (b) can be carried out by conventional methods using a base or acid, a Dy(OTf)3 type catalyst (Liang et al., Asian J. Org. Chem., 10.1002 / ajoc.201700481), or a quaternary ammonium cyanide salt type compound (see U.S. Patent No. 7,173,156). Preferably, deprotection b) is basic deprotection in the presence of the alcohol defined above. This is generally carried out by adding an alkaline hydroxide, preferably NaOH or KOH. The addition can be done dropwise. The deprotection step b) may also preferably be acidic deprotection in the presence of the alcohol defined above. This can be done using hydrochloric acid, methanesulfonic acid, or methanesulfonic anhydride. When the deprotection is acidic, it is preferable to use the alcohol defined above as the solvent.

[0049] sulfonic acid The sulfonic acid is preferably an organic sulfonic acid, and preferably an anhydrous one. Sulfonic acids may be of the following general formula (III). R2-SO3H (III) In the formula, R2 represents the following: -1 or more identical or different halogen atoms are optionally substituted in whole or in part, preferably an alkyl radical as defined above, or - A linear or branched saturated hydrocarbon chain containing 1 to 4 carbon atoms, preferably an aryl radical as defined above, which may be optionally substituted. The halogen atom can be selected from fluorine, chlorine, and bromine. In particular, the alkyl can be perhalogenated, and more specifically, perfluorinated. Preferably, the sulfonic acid is an alkanesulfonic acid, which is preferably an anhydride (wherein R2 is alkyl).

[0050] Therefore, sulfonic acids (and their anhydrous forms) Methanesulfonic acid, ethanesulfonic acid, n-propanesulfonic acid, isopropanesulfonic acid, n-butanesulfonic acid, isobutanesulfonic acid, sec-butanesulfonic acid, tert-butanesulfonic acid, trifluoromethanesulfonic acid, para-toluenesulfonic acid, benzenesulfonic acid, and mixtures thereof in any proportion of two or more of these. You can choose from these options. In a particularly preferred embodiment, the sulfonic acid used in the context of the present invention is methanesulfonic acid (MSA) or methanesulfonic anhydride (AMSA).

[0051] The sulfonic acid may or may not be supported. Preferably, it is not supported. When supported, for example, a styrene-divinylbenzene copolymer type sulfonated resin, such as Amberlyst® 15 resin or Nafion®, can be used. For example, 0.1 to 10 equivalents of acid are used in polythioesters. For example, 3 to 60 equivalents (molar equivalents), preferably 3 to 20 equivalents of alcohol, are used in the polythioester.

[0052] The deprotection step b) can be carried out at a temperature of 10°C to 100°C, preferably 25°C to 80°C, and more preferably 40°C to 80°C. This is generally carried out at atmospheric pressure. Steps a) and b) can be carried out in the same reactor. For example, a batch reactor can be used.

[0053] The subsequent conventional recovery and / or purification steps of the polythiol recovered at the end of step b) can be carried out according to the desired degree of purity. For example, if deprotection is carried out by the addition of a base, the reaction medium may be subsequently acidified; conversely, if deprotection is carried out by the addition of an acid, the reaction medium may be basicized. Subsequently, the resulting organic phase containing various thiols (particularly polythiols and (x-1)thiols) can be extracted and, if desired, concentrated. Therefore, in particular, the resulting polythiol may be in the form of a polythiol composition described below.

[0054] Composition according to the present invention When polythiols are prepared from terpenes or terpene derivatives having x C=C double bonds, the conversion of these double bonds to -SH groups is generally incomplete, and by-products may be formed at various steps in the process, regardless of the process used. Therefore, according to the present invention, the term "polythiol" refers to a polythiol containing x -SH groups, corresponding to a starting terpene or starting terpene derivative. In this case, the conversion of the x C=C double bonds at the starting point to -SH groups is complete. According to the present invention, the term "(x-1) thiol" refers to a thiol containing (x-1) -SH groups, corresponding to a starting terpene or starting terpene derivative. The term "corresponding to a starting terpene or starting terpene derivative" is understood to mean that the structure of the starting terpene or starting terpene derivative and the structure of the obtained (x-1) thiol are identical except for the x C=C double bonds that have been converted into (x-1) -SH groups. In this case, the conversion of the C=C double bonds to -SH groups is incomplete, and one -SH group is missing.

[0055] The following are examples of C=C double bonds that are not converted to SH groups: - It is still in the form of a C=C double bond, or - This is the form of an unprotected thioester group. Therefore, although (x-1) thiols can have various structures, unless otherwise specified, they are treated collectively under this general term that characterizes the number of -SH groups. This also includes (x-1) thiols that are positional isomers of the double bond. For example, during step a), an (x-1) thioester can be formed. In this case, out of x starting C=C double bonds, only (x-1) C=C double bonds react with the thiocarboxylic acid to form an (x-1) thioester group.

[0056] Furthermore, there is a possibility that deprotection may not be completed during step b). Therefore, according to the process according to the present invention, The following can be formed: - (x-1) thiol from the (x-1) thioester formed in step a), and / or - (x-1) thiols from polythioesters that are not completely deprotected.

[0057] Therefore, a polythiol composition obtained from a terpene having x C=C double bonds, or from a terpene derivative, wherein the polythiol composition comprises the following: - A polythiol corresponding to the terpene or terpene derivative containing x -SH groups, and A thiol corresponding to the terpene or terpene derivative containing (x-1) -SH groups (where x is as defined above). Such compositions may optionally contain other by-products or impurities (e.g., monothiols).

[0058] In particular, a trithiol composition can be obtained from a terpene or terpene derivative having three C=C double bonds, and the trithiol composition comprises the following: - Trithiol corresponding to the terpene, and - A dithiol corresponding to the aforementioned terpene.

[0059] In particular, a tetrathiol composition can be obtained from a terpene or terpene derivative having four C=C double bonds, and the tetrathiol composition includes the following: - A tetrathiol corresponding to the terpene or the terpene derivative, and - A trithiol corresponding to the terpene or terpene derivative.

[0060] Therefore, the present invention relates to a polythiol composition A obtained from a terpene or terpene derivative having x C=C double bonds, wherein the polythiol composition comprises the following: - A polythiol corresponding to the terpene or terpene derivative containing x -SH groups, and A thiol corresponding to the terpene or terpene derivative containing (x-1) -SH groups (where x is as defined above).

[0061] In particular, composition A contains at least 50% by weight, preferably at least 60% by weight, for example at least 70% by weight, more preferably at least 80% by weight, and more preferably at least 90% by weight, for example at least 95% by weight, based on the total weight of composition A. In particular, composition A contains less than 40% by weight, preferably less than 30% by weight, and more preferably less than 25% by weight of the (x-1) thiol, based on the total weight of composition A.

[0062] Preferably, the weight ratio of composition A

number

[0063] In a particularly preferred method, composition A is obtained from a terpene or terpene derivative selected from myrcene, farnesene, squalene, isosqualene, humulene, and dihydrofarnesene.

[0064] Polythiol according to the present invention The present invention also relates to trithiols obtained from dihydrofarnesene, heptatiols obtained from isosqualene, and tetrathiols obtained from camphorene (i.e., trithiols corresponding to dihydrofarnesene, heptatiols corresponding to isosqualene, and tetrathiols corresponding to camphorene). Preferably, the trithiol is the trithiol of dihydro-β-farnesene. The trithiol of dihydrofarnesene may be, in particular, one of the following positional isomers. [Chemical formula 10] [ka] [Chemical formula 11] [ka] [Chemical formula 12] [ka] [Chemical formula 13] [ka]

[0065] The dihydrofarnesene trithiol can be obtained from a starting composition containing at least 70% by weight of dihydrofarnesene, more preferably at least 80% by weight of dihydrofarnesene, based on the total weight of the composition. Preferably, the composition contains at least 85% by weight of dihydrofarnesene, based on the total weight of farnesene, all partially hydrogenated compounds resulting from the hydrogenation of farnesene, and farnesane present in the composition. More specifically, the composition is a trithiol of a dihydro-β-farnesene composition obtained from Myralene 10 (trademark).

[0066] The heptatiol of isosqualene can be, in particular, one of the following positional isomers. [Chemical formula 14] [ka] [Chemical formula 15] [ka] [Chemical formula 16] [ka] [Chemical formula 17] [ka]

[0067] The present invention also relates to polythiols obtained from β-carotene, lycopene, farnesol, retinol, retinal, vitamin A, nerolidol, isomylsenol, and ipsdienol. These compounds are novel and form part of the present invention. The present invention also relates to compositions defined above that can, can, or can be obtained by the processes according to the present invention. The same applies to polythiols defined above that can, can, or can be obtained by the processes according to the present invention.

[0068] Unless a specific isomer is mentioned, the name of a compound is understood to include all of its possible positional isomers. The following examples are provided for illustrative purposes only and are not intended to limit the present invention. [Examples]

[0069] Example 1 Trithiol of dihydro-β-farnesene obtained from Myralene 10 (trademark) by the process according to the present invention Process a) 48.7 g (0.64 mol) of TAA is introduced into a 250 ml jacketed reactor. The medium is placed under stirring at 5°C. Air is blown into the reaction medium through the frit at a flow rate of approximately 0.4 Sl / h, and nitrogen is circulated into the reactor headspace at a flow rate of approximately 4 Sl / h. Next, 40 g (0.19 mol) of Myralene 10 (trademark) is added dropwise via a peristaltic pump over approximately 27 minutes. Once the addition is complete, 35.7 g (0.77 mol) of ethanol is added to the reaction medium. The reaction medium is stirred overnight at 5°C. GC / FID analysis demonstrates the complete transformation of Myralene 10. Cut off the air supply.

[0070] Basic deprotection step b) Next, 26.8 g (0.58 mol) of ethanol is added to the reaction medium. Then, the reaction medium is degassed under nitrogen for 1 hour, and then cooled to approximately 10°C. 103 g (0.64 mol) of 25% sodium hydroxide solution, which had been degassed beforehand, is added via a dropping funnel for 38 minutes. The reaction medium is stirred under nitrogen at 10°C overnight, and then at 25°C for 6 hours. GC / FID analysis shows complete conversion of trithioacetate.

[0071] Recovery process Subsequently, the reaction medium is cooled to 20°C, and then 117 g (0.64 mol) of 20% HCl (pre-degassed with nitrogen) is added dropwise to the reaction medium via a peristaltic pump. The trithiol phase is removed. The aqueous phase is extracted three times with 16.5 g (0.19 mol) of dichloromethane. The organic phases are combined, then washed four times with 7 g (0.39 mol) of water, and then concentrated using a rotary evaporator.

[0072] A composition is obtained that contains 82.29% by weight of dihydro-β-farnesene trithiol and 9.71% by weight of dihydro-β-farnesene dithiol, based on the total weight of the composition. weight ratio

number

[0073] Example 2 Myrcene trithiol obtained by the process according to the present invention Process a) 64.5 g (0.85 mol) of TAA is introduced into a 250 ml jacketed reactor. The medium is left to stand at 5°C with stirring, and then 5.9 g (0.13 mol) of ethanol is rapidly added. Air is blown into the reaction medium through the frit at a flow rate of approximately 0.4 Sl / h, and nitrogen is circulated into the reactor headspace at a flow rate of approximately 4 Sl / h. Next, 35 g (0.26 mol) of myrcene is added dropwise via a peristaltic pump over approximately 22 minutes. Once the addition is complete, 23.7 g (0.51 mol) of ethanol is added to the reaction medium. The reaction medium is stirred overnight at 5°C. GC / FID analysis shows complete conversion of myrcene. Cut off the air supply.

[0074] Basic deprotection step b) Next, 82.9 g (1.80 mol) of ethanol is added to the reaction medium. Then, the reaction medium is degassed under nitrogen for 1 hour, and then the temperature is raised to approximately 30°C. 73.7 g (0.85 mol) of the previously degassed 46% sodium hydroxide solution is added via a dropping funnel. The reaction medium is stirred under nitrogen at 40°C for 21 hours. GC / FID analysis shows complete conversion of trithioacetate.

[0075] Recovery process The reaction medium is then cooled to 20°C, and 154.6 g (0.85 mol) of 20% HCl (pre-degassed with nitrogen) is added dropwise to the reaction medium via a peristaltic pump. The trithiol phase is removed. The aqueous phase is extracted three times with 21.8 g (0.26 mol) of dichloromethane. The organic phases are combined, then washed four times with 9.2 g (0.51 mol) of water, and then concentrated using a rotary evaporator.

[0076] A composition is obtained that contains 50.56% by weight of myrcene trithiol and 23.6% by weight of myrcene dithiol, based on the total weight of the composition. weight ratio

number

[0077] Example 3 Tetrathiol obtained from farnesene by the process according to the present invention Process a) 163.9 g (2.15 mol) of TAA is introduced into a 1-liter jacketed reactor. The medium is left to stand at 5°C with stirring, and then 23.0 g (0.50 mol) of ethanol is rapidly added. Air is blown into the reaction medium through the frit at a flow rate of approximately 0.4 Sl / h, and nitrogen is circulated into the reactor headspace at a flow rate of approximately 4 Sl / h. Next, 100 g (0.49 mol) of farnesene, sold under the trade name Biofene®, is added dropwise via a peristaltic pump over approximately 47 minutes. Once the addition is complete, 90.1 g (1.96 mol) of ethanol is added to the reaction medium. The reaction medium is stirred overnight at 5°C. GC / FID analysis demonstrates the complete conversion of farnesene and its reaction intermediates. Cut off the air supply.

[0078] Basic deprotection step b) Subsequently, the reaction medium is degassed under nitrogen for 1 hour, then cooled to approximately 10°C, and 187.2 g (2.15 mol) of the previously degassed 46% sodium hydroxide solution is added via a dropping funnel for 35 minutes. The reaction medium is stirred under nitrogen at 25°C for 19 hours. GC / FID analysis demonstrates complete conversion of tetrathioacetate.

[0079] Recovery process Subsequently, the reaction medium is cooled to 20°C, and then 294.4 g (1.61 mol) of 20% HCl (pre-degassed with nitrogen) is added dropwise to the reaction medium via a peristaltic pump. The tetrathiol phase is removed. The aqueous phase is extracted three times with 41.6 g (0.49 mol) of dichloromethane. The organic phases are combined, then washed four times with 17.6 g (0.98 mol) of water, and then concentrated using a rotary evaporator.

[0080] A composition is obtained that contains 61.24% by weight of farnesene tetrathiol and 25.77% by weight of farnesene trithiol, based on the total weight of the composition. weight ratio

number

Claims

1. a) A terpene or terpene derivative is added to oxygen (O ２ ) and a step of reacting with a thiocarboxylic acid in the presence of at least one organic solvent to obtain a reaction medium containing a polythioester and the at least one organic solvent, and b) A step of performing a deprotection step on the polythioester obtained in step a) to obtain a polythiol, Steps a) and b) are performed in one-pot synthesis. Preparation process for polythiols.

2. The deprotection step b) is basic deprotection, preferably carried out by the addition of an alkali hydroxide. The preparation process according to claim 1.

3. Deprotection step b) is preferably acidic deprotection in the presence of an alcohol. The preparation process according to claim 1.

4. The organic solvent is selected from the group consisting of alcohols, ethers, organochlorinating solvents, carboxylic acids, and mixtures thereof. The preparation process according to any one of claims 1 to 3.

5. The aforementioned organic solvent is selected from alcohols of the following general formula (IV): R ４ -OH (IV) In the formula, R ４ This represents a linear, branched, or cyclic saturated hydrocarbon group containing 1 to 10, preferably 1 to 4, carbon atoms. The preparation process according to any one of claims 1 to 4.

6. The thiocarboxylic acid is thioacetic acid. The preparation process according to any one of claims 1 to 5.

7. The terpene or terpene derivative is selected from the group consisting of myrcene, farnesene, squalene, isosqualene, humulene, and dihydrofarnesene. The preparation process according to any one of claims 1 to 6.

8. A polythiol composition A obtained from a terpene or terpene derivative having x C=C double bonds, - A polythiol corresponding to the terpene or terpene derivative containing -x -SH groups, and A thiol corresponding to the terpene or terpene derivative containing -(x-1) -SH groups, x is an integer greater than or equal to 3. Polythiol composition A.

9. weight ratio [Math 1] The ratio is 1:1 to 50,000:1, preferably 2:1 to 50,000:

1. The polythiol composition A according to claim 8.

10. The terpene or terpene derivative is selected from the group consisting of myrcene, farnesene, squalene, isosqualene, humulene, and dihydrofarnesene. The polythiol composition A according to claim 8 or claim 9.

11. Selected from trithiol obtained from dihydrofarnesene, heptatiol obtained from isosqualene, and tetrathiol obtained from camphorene, Polythiol.

12. The following formula 【Chemistry 1】 【Chemistry 2】 【Transformation 3】 【Chemistry 4】 【Transformation 5】 【Transformation 6】 【Transformation 7】 【Transformation 8】 Having one of the following: The polythiol according to claim 11.

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