Polyethylene compositions and methods for preparing them from terpenes or terpene derivatives.

Abstract

The present invention relates to a method for preparing a polythiol from a terpene or terpene derivative, and to polythiol compositions and novel polythiols. The method comprises the following steps: a) reacting a terpene or a terpene derivative with a thiocarboxylic acid in the presence of oxygen (O2) and of at least one organic solvent so as to obtain a reaction medium comprising a polythioester and the at least one solvent; b) deprotecting the polythioester obtained in step a) so as to obtain a polythiol; wherein step a) and step b) are carried out in one-pot synthesis.

Description

[0001] The present invention relates to a process for preparing polythiol compositions using terpenes or terpene derivatives as starting reagents and also to the polythiol compositions obtainable by this process.

[0002] Polythiols are molecules of major industrial interest. They are used, for example, as crosslinking agents, particularly at low temperatures.

[0003] Currently, there are several synthetic routes for obtaining polythiols. Among the most widely used methods, mention can be made of the reaction between polyols and mercaptoacids (described, for example, in US Application 2005153231). Although this reaction is easy and makes it possible to obtain varied polythiol structures, the products obtained generally exhibit low resistance to hydrolysis because of the negligible presence of ester functions.

[0004] Alternatively, the direct addition of hydrogen sulfide to polyenes by acid or photochemical catalysis makes it possible to obtain molecules without hydrolyzable functions. This additive is described in particular in Application WO 12018757. However, with this method, large quantities of sulfide-type compounds can be co-produced and, depending on the reagents used, conversion problems may arise. Thus, the molecules obtained may comprise numerous unconverted double bonds, which generate stability problems and decrease the overall content of -SH functions. In the case of a triene-type starting reagent, for example, this is reflected in particular by the presence of mono- and / or dithiols in a large quantity in the composition obtained.

[0005] In fact, controlling and / or reducing the formation of these byproducts, such as mono- and / or dithiols, is important depending on the targeted application fields. This is because their content influences the degree of crosslinking of subsequently prepared materials, particularly thermosetting materials produced from a resin and a polythiol-type hardener. It has thus been demonstrated that the degree of crosslinking influences the physical and viscoelastic properties of polymers, such as their density, modulus, elastic range limits, or glass transition temperature (Tg). Tg is Petition 870250083211, dated 09 / 16 / 2025, page 14 / 45 2 / 27 conventionally determined by the DSC method for Differential Scanning Calorimetry or by dynamic mechanical analysis (DM(T)A).

[0006] These parameters are directly related to the behavior of materials, such as hardness, elasticity, flexibility, or tear resistance. In particular, the aim is to obtain polymers with a high glass transition temperature, in order to obtain materials with higher thermal resistance (that is, that retain their characteristics over a wider temperature range).

[0007] There is therefore a need for a process for the industrial preparation of polythiols that makes it possible to control, indeed even maximize, the conversion of C=C double bonds into -SH functions. There is also a need for a process for the preparation of polythiols that makes it possible to control, indeed even reduce, the formation of by-products (e.g., mono- and / or dithiols in the case of trithiol preparation, or also sulfides).

[0008] One technical solution involves passing through polythioester intermediates: the C=C double bonds are converted into R'-C(O)-SR functions, which are then deprotected to obtain the desired polythiols. However, these polythioester intermediates represent a huge technical difficulty for industrial use. They are generally very viscous compounds, indeed even solids. They are therefore difficult to handle in order to be involved in the deprotection stage. They thus cause many practical problems at the industrial level and are in reality little used.

[0009] Furthermore, these polythioesters are conventionally obtained by the reaction of a polyene with a thiocarboxylic acid, in particular thioacetic acid. However, this reaction involves the use of a large excess of thiocarboxylic acid, which must be removed before the deprotection stage. Thus, additional stages of evaporation of this excess thiocarboxylic acid and / or purification of the polythioesters are necessary in order to carry out the subsequent deprotection stage.

[0010] Finally, the reagents used in this type of process are generally hydrocarbons derived from petroleum. In view of environmental and climate challenges Petition 870250083211, dated 09 / 16 / 2025, page 15 / 45 3 / 27 currents, processes are desired that utilize bio-based and / or renewable starting materials.

[0011] There is therefore a need for an improved process for the preparation of polythiols, via polythioesters.

[0012] There is also a need for an improved process for the preparation of polythiols from bio-based and / or renewable starting materials.

[0013] There is a need regarding polythiol compositions, the content of -SH functions which is controlled, indeed even maximized. The term “content of -SH functions” is understood to mean the ratio of the weight of all -SH functions / total weight of the composition.

[0014] There is also a need for polythiol compositions obtained from bio-based and / or renewable materials.

[0015] It is an object of the present invention to provide an improved process for the preparation of polythiol compositions from terpenes or from terpene derivatives, the industrial implementation of which is simplified.

[0016] It is an object of the present invention to provide an improved process for the preparation of polythiol compositions from terpenes or from terpene derivatives, whereby the content of -SH functions is controlled, indeed even maximized.

[0017] It is also an objective of the present invention to provide improved polythiol compositions, in particular with a controlled, indeed maximized, content of -SH functions.

[0018] It is also an objective of the present invention to provide polythiol compositions obtained from bio-based and / or renewable starting materials, namely terpenes and terpene derivatives.

[0019] It is an object of the present invention to provide polythiol compositions for use in the preparation of polymers, preferably thermosetting polymers.

[0020] The present invention meets, in whole or in part, the above objectives.

[0021] The present inventors have surprisingly discovered that it is possible to use a “one-container” process for the synthesis of polythiols from terpenes or terpene derivatives. The term “one-container process” Petition 870250083211, dated 09 / 16 / 2025, p. 16 / 45 4 / 27 container” is understood to mean in particular a process in which the synthesis intermediates (i.e., the polythioesters such as according to the invention) are not isolated from the reaction medium in order to carry out the subsequent deprotection step. In the context of the industrial synthesis of polythiols, such a one-vessel process exhibits numerous advantages.

[0022] In particular, the stage for forming polythioester intermediates according to the invention (hereinafter stage a)) makes it possible to obtain very good conversion (in particular between 90% and 100% conversion of the terpene or terpene derivative) while avoiding the use of a very large excess of thiocarboxylic acid. In fact, a large excess of thiocarboxylic acid is conventionally used in prior art processes, which represents a loss to the process and generates a large amount of residue to be isolated and treated. Furthermore, such an excess is not compatible with a “single vessel” process because it needs to be removed before the deprotection stage. The present invention makes it possible to avoid these disadvantages, which represent an economic advantage, but also an environmental advantage.

[0023] Another advantage of the present invention is that the reaction medium comprising the polythioester intermediates obtained at the conclusion of stage a) can be easily stirred and handled. In particular, it can exist in the form of a liquid or a suspension, which is viscous or slightly viscous. Difficulties of operability at the industrial level are thus avoided.

[0024] The reaction medium comprising the polythioester intermediates is also compatible with the deprotection stage (hereinafter stage b)), which represents a simplification of the process.

[0025] Thus, stages a) and b) as per the invention are carried out as a “single vessel” reaction. The process is thus markedly improved because intermediate stages of removing excess thiocarboxylic acid and / or purifying polythioester intermediates, such as extraction, recrystallization and / or distillation, are thus avoided.

[0026] Furthermore, terpenes and their derivatives may prove particularly useful as starting polyenes leading to polythiols. Terpenes and their derivatives address many current environmental and climate problems. They are Petition 870250083211, dated 09 / 16 / 2025, page 17 / 45 5 / 27 generally based on biological sources, meaning they result from renewable organic matter (biomass) of plant or animal origin. They also exhibit a huge diversity of structures, which allows for greater versatility of uses.

[0027] The polythiol compositions obtainable by the process according to the invention are novel and exhibit a controlled, indeed even maximized, -SH content. They are distinguished in particular by a high (x-ijthioKols) by weight ratio as defined below. They are particularly suitable for the preparation of materials such as thermosetting plastics from resins. Thus, the present invention makes it possible to obtain materials with superior properties. For example, polymers having a higher Tg, thus superior thermal resistance and / or superior compressive strength properties and / or a higher modulus and a wider elastic range, can be obtained.

[0028] Thus, the present invention relates to a process for the preparation of a polythiol comprising the following stages: (a) A terpene or a terpene derivative is reacted with a thiocarboxylic acid in the presence of oxygen (O2) and at least one organic solvent, so as to obtain a reaction medium comprising a polythioester and said at least one organic solvent; and b) a deprotection step of the polythioester obtained in step a) is performed, in order to obtain a polythiol;

[0029] where stage a) and stage b) are carried out in a single container synthesis.

[0030] The present invention relates to a polyol A composition obtained from a terpene or from a terpene derivative having x C=C double bonds, said composition comprising: - the polythiol corresponding to said terpene or said terpene derivative comprising x -SH functions; and - the thiol(s) corresponding to said terpene or to said terpene derivative comprising (x-1) -SH functions, with x being an integer greater than or equal to 3; and preferably wherein the ratio Petition 870250083211, dated 09 / 16 / 2025, page 18 / 45 6 / 27 —-——— by weight is between 1:1 and 50,000:1, preferably between (xl)thiol(ols)rr 2:1 and 50,000:1.

[0031] The present invention also relates to a polythiol chosen from trithiol obtained from dihydrofarnesene, heptathiol obtained from isosqualene and tetrathiol obtained from camphorene.

[0032] The term “alkyl” is understood to mean in particular a saturated, linear, branched or cyclic hydrocarbon radical comprising from 1 to 10, preferably from 1 to 4, carbon atoms.

[0033] The term “aryl” is understood to mean in particular an aromatic cyclic hydrocarbon radical (monocyclic, bicyclic or tricyclic) comprising from 6 to 10 carbon atoms, preferably a phenyl or a naphthyl, more preferably a phenyl.

[0034] The term “aralkyl” is understood to mean in particular an alkyl substituted by an aryl, for example benzyl. Terpenes

[0035] The term “terpenes” is understood to mean in particular linear, branched or cyclic hydrocarbon compounds consisting of repeating units of isoprene (C5C8)n, n being an integer between 2 and 8, preferably between 2 and 6. In particular, said terpenes comprise at least three C=C double bonds. Preferably, said terpenes comprise 3, 4, 5 or 6 C=C double bonds.

[0036] Terpenes are frequently commercially available in the form of compositions comprising different isomers, the proportions of which may vary (in particular as a function of the process by which they are obtained). Such compositions fall within the scope of the present invention and can be used directly as a starting reagent.

[0037] Terpene families are conventionally categorized based on the value of n (with the corresponding number of carbon atoms), according to the table below: [Table 1] Value 2 (C10) 3 (C15) 4 (C20) 5 (C25) 6 (C30) 8 (C40) Petition 870250083211, dated 09 / 16 / 2025, p. 19 / 45 7 / 27 of the Monoterpene Family Sesquiterpenes Diterpenes Sesterterpenes Triterpenes Tetraterpenes

[0038] In particular, terpenes are selected from monoterpenes, triterpenes, and sesquiterpenes. More specifically, terpenes are selected from linear or branched terpenes.

[0039] Mention may be made, among the preferred terpenes, of myrcene and farnesene.

[0040] Myrcene:

[0041] Myrcene is a monoterpene. There are several isomers of myrcene, including ocimene and allo-ocimene. In particular, mention may be made of amyrcene, β-myrcene, cis-α-ocimene, trans-α-ocimene, cis-ocimene, trans-β-ocimene, 4-cis-6-cis-aloo-ocimene, 4-cis-6-trans-aloo-ocimene, 4-trans-6-cis-aloocimene and 4-trans-6-trans-aloo-ocimene (as per [Figure 1]). Preferably, use is made of β-myrcene, which is the natural form (CAS No.: 123-35-3), of the following formula: [Chem 1]

[0042] Farneseno:

[0043] Farnesene is a sesquiterpene. It exists in the form of two isomers: α-farnesene (CAS No.: 502-61-4) and β-farnesene (CAS No.: 502-60-3) with the following formulas: [Chem 2] Petition 870250083211, dated 09 / 16 / 2025, p. 20 / 45 8 / 27

[0044] More particularly, mention may be made of cis-α-farnesene, trans-α-farnesene, cis-3-farnesene and trans-β-farnesene. β-Farnesene is preferred and even more preferably trans-β-farnesene (CAS No.: 18794-84-8).

[0045] Use may be made, like other terpenes, of humulene (CAS 6753-98-6), elemene, germacrene, bisabolene, cembrene, casbene, zingiberene, camphorene and their isomers. In particular, mention may be made of the following isomers: a-elemene, β-elemene, γ-elemene, δ-elemene, germacrene A, germacrene B, germacrene C, germacrene D, germacrene E, α-bisabolene, β-bisabolene and γ-bisabolene.

[0046] Terpene derivatives:

[0047] The term “terpene derivatives” is understood in particular to mean compounds whose structure is derived from that of terpenes. They may result from the chemical transformation of the latter or may exist naturally. In particular, said terpene derivatives comprise at least three C=C double bonds, for example between 3 and 10 C=C double bonds.

[0048] Mention may be made of the following terpene derivatives.

[0049] Hydrogenated terpene derivatives or hydrogenated terpenes:

[0050] The term “hydrogenated derivative of a terpene” is understood in particular to mean a compound of empirical formula (C5nH8n+2z), z being an integer at least equal to 1 and n being as defined above. Preferably, z is between 1 and 10, more preferably between 1 and 3.

[0051] Among the hydrogenated derivatives, squalene and dihydrofarnesene are particularly preferred.

[0052] Squalene (CAS No.: 111-02-4) has the following formula:

[0053] It has the empirical formula C30H50.

[0054] Dihydrofarnesene has the empirical formula C15H26·. It can exist in the form of different isomers depending on the double bond of the hydrogenated farnesene and on the α or β isomer of the farnesene chosen. Dihydro-β-farnesene (and all of its isomers) is preferred.

[0055] More particularly, the following isomers of dihydrofarnesene can be used according to the present invention: Petition 870250083211, dated 09 / 16 / 2025, page 21 / 45 9 / 27 [Chem 3] [Chem 4] [Chem 5]

[0056] When partial hydrogenation of farnesene (C15H24) is carried out, it is also possible to obtain a composition comprising dihydrofarnesene and one or more other partially hydrogenated compounds chosen from:

[0057] tetrahydrofarnesene (C15H28) and hexahydrofarnesene (C15H30). Such a composition can be used as a starting reagent in the context of the present invention: the dihydrofarnesene it contains will give the corresponding trithiol according to the process according to the invention. Preferably, such a composition comprises at least 70% by weight of dihydrofarnesene, more preferably at least 80% by weight of dihydrofarnesene, with respect to the total weight of the composition. Preferably again, said composition comprises at least 85% by weight of dihydrofarnesene, with respect to the total weight of unreacted farnesene, of all the partially hydrogenated compounds resulting from farnesene and farnesane present in the composition. In this type of composition, it is particularly preferred to use the β isomer of farnesene, in order to obtain dihydrofarnesene.

[0058] Thus, mention may preferably be made of Myralene 10® (CAS No.: 1581740-29-5), a composition obtained from the partial hydrogenation of βfarnesene and the preparation process of which is given in Application WO 2016 / 064853. Petition 870250083211, dated 09 / 16 / 2025, p. 22 / 45 10 / 27 Myralene 10® predominantly comprises dihydrofarnesene. Such a composition is entirely suitable as a starting reagent according to the present invention.

[0059] Terpenoids:

[0060] The term “terpenoids” is understood in particular to mean compounds, the structure of which is derived from terpenes and which optionally comprise one or more heteroatoms (in particular oxygen and / or nitrogen, preferably oxygen) and / or one or more chemical functions. For example, terpenoids may comprise at least one function chosen from among the alcohol, ketone, ether, ester or aldehyde functions.

[0061] They may in particular be of the empirical formula (C5nH8n-2y), with n as defined above and y being an integer between 1 and 4.

[0062] Preferably, the terpenoid is chosen from the group consisting of:

[0063] cosmene, β-carotene, lycopene, farnesol, retinol, retinal, vitamin A, nerolidol, isomyrcenol and ipsdienol.

[0064] Oligomers of terpenes and / or hydrogenated derivatives of terpenes and / or terpenoids:

[0065] The term “oligomer” corresponds in particular to an assembly of 2 to 10 terpenes and / or hydrogenated derivatives of terpenes 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.

[0066] Particular mention may be made of the β-farnesene dimer, called isosqualene, of empirical formula C30H48 and of the following formula (for example as described in US document 2011 / 0287988A1): [Chem 6] ch2ch^ ch3 Petition 870250083211, dated 09 / 16 / 2025, p. 23 / 45 11 / 27

[0067] The following isomers of isosqualene can also be used according to the present invention: [Chem 7] T6.

[0068] Thus, the term “terpenes and terpene derivatives” is preferably understood to mean:

[0069] terpenes, hydrogenated terpene derivatives, terpenoids and oligomers of terpenes and / or hydrogenated terpene and / or terpenoid derivatives.

[0070] Thus, the said terpene or terpene derivative may be chosen from the group consisting of:

[0071] myrcene, farnesene, humulene, elemene, germacrene, bisabolene, cosmene, cembrene, casbene, zingiberene, β-carotene, lycopene, camphorene, squalene, isosqualene, dihydrofarnesene, farnesol, retinol, retinal, vitamin A, nerolidol, isomyrcenol and ipsdienol.

[0072] More preferably, the terpene or terpene derivative is chosen from the group consisting of: myrcene, farnesene, squalene, isosqualene, humulene and dihydrofarnesene. Petition 870250083211, dated 09 / 16 / 2025, page 24 / 45 12 / 27

[0073] Such starting materials are naturally present in plants, in marine species, or can be produced by fermentation, by genetically modified or non-genetically modified organisms, and possibly using renewable carbon sources. They are also commercially available. For example, Amyris sells trans-p-farnesene under the name Biofene®, and DRT sells myrcene. Politióis

[0074] According to the invention, the term “polythiol” refers to the polythiol corresponding to the starting terpene or to the starting terpene derivative as defined above.

[0075] 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 polythiol are identical, with the exception of the C=C double bonds, which have been converted into -SH functions (i.e., -CH-C(SH)-): for x C=C double bonds of the starting terpene or starting terpene derivative, x -SH functions are obtained. Also included under the term “polythiol” are polythiols that are positional isomers of the double bonds.

[0076] The number of C=C double bonds contained in said terpene or terpene derivative is thus referred to herein as “x”, x being an integer, preferably greater than or equal to 3. Preferably, x is between 3 and 10, more preferably between 3 and 7. The polythiols according to the invention may also be referred to as (x)thiols, with x as defined above. Polythioester intermediates

[0077] The term “polythioester intermediate” or “polythioester” is understood to mean the polythioester corresponding to the starting terpene or to the starting terpene derivative. The term “corresponding to the starting terpene or to the starting terpene derivative” is understood to mean that the structure of the starting terpene or to the starting terpene derivative and of the resulting polythioester is identical, with the exception of the C=C double bonds, which have been converted into -CH-C(O)-S-Ri functions (Ri depends on the thiocarboxylic acid used; preferably, Ri is a methyl): for x C=C double bonds, x thioester functions are obtained, with x as defined above. Petition 870250083211, dated 09 / 16 / 2025, p. 25 / 45 13 / 27 Also included under the term “polythioesters” are polythioesters that are positional isomers of the terpene double bonds or derived from the initial terpene. PROCESS ACCORDING TO THE INVENTION Stage a)

[0078] During stage a), a terpene or a terpene derivative as defined above is reacted with a thiocarboxylic acid in the presence of oxygen (O2) and at least one organic solvent, so as to obtain a reaction medium comprising a polythioester as defined above and said at least one organic solvent.

[0079] The reaction is as follows: R-CH=CH-R + Ri-C(O)-SH → R-CH2-CH(SC(O)-Ri)-R

[0080] Stage a) is carried out in the presence of oxygen (O2), acting here as the initiator of the reaction. Stage a) can thus be carried out in the presence of air, exhausted air (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 for the entire duration of stage a).

[0081] In particular, oxygen is bubbled into the reaction medium, preferably in the form of exhausted air. For example, exhausted air is passed through a frit or a diffuser that is immersed within the reaction medium. Alternatively, oxygen can be bubbled into the reaction medium and nitrogen can be introduced into the gas phase of the reactor (i.e., into the free top of the reactor).

[0082] The oxygen flow rate may be between 0.01 and 100 Sl / h, preferably between 0.05 and 10 Sl / h, more preferably between 0.05 and 5 Sl / h, in particular between 0.05 and 2 Sl / h (standard liters / h).

[0083] Stage a) is carried out in particular in the absence of any other reaction initiator and more preferably in the absence of AIBN (azobisisobutyronitrile) and / or in the absence of UV radiation.

[0084] Stage 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 chosen very specifically. The solvent(s) may be Petition 870250083211, dated 09 / 16 / 2025, p. 26 / 45 14 / 27 polar protic or polar aprotic solvent(s). Mention may be made, among the solvents that may be used, of: alcohols, ethers (preferably cyclic ethers and glycol ethers, such as, for example, dialkyl glycol ethers), organochlorine solvents, carboxylic acids or mixtures thereof.

[0085] Preference is given to alcohols, in particular of the following general formula (IV): R4-OH (IV)

[0086] where R4 represents an alkyl group as defined above. Preferably, the alcohol is chosen from the group consisting of: methanol, ethanol, isopropanol, n-propanol, n-butanol, butan-2-ol, isobutanol and tert-butanol, most preferably ethanol.

[0087] Preferably, the solvent is chosen 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 referred to as glima), dietoxyethane, dibutoxyethane and mixtures thereof, more preferably ethanol.

[0088] The amount of solvent used is generally chosen as a function of the desired viscosity of the reaction medium. Complete or partial dissolution can be carried out by a person skilled in the art, depending on the target viscosity of the reaction medium. Preferably, between 1 molar eq. and 50 molar eqs., more preferably between 1 eq. and 20 eqs., of solvent(s), with respect to the terpene or terpene derivative, is / are used.

[0089] The solvent can be added from the beginning of stage a), completely or partially. It can be added all at once, in several attempts (semi-continuously) or gradually (continuously), during stage a).

[0090] The thiocarboxylic acid is preferably of the following general formula (II): Ri-C(O)-SH(ll)

[0091] where:

[0092] Ri represents an alkyl radical, an aryl radical or an aralkyl radical as defined above.

[0093] Preferably, R1 is chosen from methyl, ethyl and benzyl. Petition 870250083211, dated 09 / 16 / 2025, p. 27 / 45 15 / 27

[0094] Thioacetic acid, for which Ri is a methyl group, is very particularly preferred according to the invention (hereinafter also referred to as ATA). For example, with thioacetic acid, a polythioacetate is obtained as a polythioester intermediate.

[0095] According to one embodiment, thiocarboxylic acid can be generated in situ (as per document US 3,270,063, Thompson Chemical Co., 1963: “Methods of Making Primary Mercaptans”): thioacetic acid can be produced from acetic anhydride and hydrogen sulfide, in the presence of a catalyst.

[0096] Preferably, in order to carry out stage a), the thiocarboxylic acid and the solvent(s) are first introduced into the reactor, then oxygen is introduced, for example by bubbling with air. The terpene or derivative can subsequently be added to the reaction medium.

[0097] The temperature of stage a) may be between 5°C and 80°C, preferably between 5°C and 50°C, more particularly between 5°C and 25°C, for example between 5°C and 10°C. Stage a) is generally carried out at atmospheric pressure.

[0098] The molar ratio of the thiocarboxylic acid / double bond of the terpene or terpene derivative may be between 1 and 20, preferably between 1 and 10, for example between 1 and 5, more preferably between 1 and 3.

[0099] Stage a) makes it possible, starting from a terpene or a terpene derivative, to form a polythioester intermediate as defined above.

[0100] The reaction medium obtained at the conclusion of stage a) can thus be understood as: - a polythioester intermediate as defined above; - the solvent or mixture of solvents as defined above; - possibly by-products, such as (xl)polythioesters; and - possibly one or more unreacted reagents.

[0101] The term “(xl)polythioester” is understood to mean in particular a compound comprising x-1 thioester functions, with x being as defined above. The same is a compound that has retained a C=C double bond (i.e., an unreacted C=C double bond).

[0102] The reaction medium may thus comprise between 10% and 85% by weight of polythioester intermediate, with respect to the whole of the reaction medium. Petition 870250083211, dated 09 / 16 / 2025, page 28 / 45 16 / 27

[0103] The reaction medium may comprise between 15% and 90% by weight of solvent(s), with respect to the whole of the reaction medium.

[0104] Stage b)

[0105] Stage b) of deprotection of the polythioester intermediate obtained in stage a) makes it possible to obtain a polythiol. This can be carried out by any means known to a person skilled in the art. As stages a) and b) are carried out in a single-vessel synthesis according to the invention, it is understood that the reaction medium comprising the polythioester obtained at the conclusion of stage a) is retained in order to carry out the deprotection stage b). Thus, stages a) and b) are carried out in the presence of the same solvent (or solvent mixture). It is possible to add more of said solvent (or said solvent mixture) during stage b). In particular, the process according to the invention does not comprise a separation and / or extraction and / or washing stage of the (organic) phase comprising the polythioester between stages a) and b). In particular, no intermediate purification stage of the polythioester is carried out.More specifically, no recrystallization and / or distillation stage of the polythioester is performed.

[0106] Deprotection b) can be carried out by conventional methods: using a base or an acid, a Dy(OTf)3 type catalyst (according to Liang et al., Asian J. Org. Chem., 10,1002 / ajoc,201700481) or a quaternary ammonium cyanide salt type compound (according to US 7 173 156).

[0107] Preferably, deprotection b) is a basic deprotection, preferably in the presence of an alcohol as defined above. It is generally carried out by the addition of an alkaline hydroxide, preferably NaOH or KOH. The addition can be carried out dropwise.

[0108] The deprotection stage b) can also be an acid deprotection, preferably in the presence of an alcohol as defined above. The same can be carried out with hydrochloric acid, methanesulfonic acid or anhydrous methanesulfonic acid. When the deprotection is acidic, it is preferable to use an alcohol as defined above as a solvent. Sulfonic acid Petition 870250083211, dated 09 / 16 / 2025, page 29 / 45 17 / 27

[0109] The sulfonic acid is preferably an organosulfonic acid that is optionally anhydrous.

[0110] Sulfonic acid can have the following general formula (III): R2-SO3H(III),

[0111] where R2 represents: - an alkyl radical, preferably as defined above, optionally substituted, in whole or in part, by one or more identical or different halogen atoms, or - an aryl radical, preferably as defined above, optionally replaced by a saturated, linear or branched hydrocarbon chain comprising from 1 to 4 carbon atoms.

[0112] The halogen atom may be chosen from fluorine, chlorine, and bromine. In particular, said alkyl may be perhalogenated, more particularly perfluorinated.

[0113] Preferably, the sulfonic acid is an alkanesulfonic acid that is optionally anhydrous (in the formula above, R2 is an alkyl).

[0114] Thus, sulfonic acids (and also their anhydrous forms) can be chosen from among:

[0115] 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 of two or more of these in all proportions.

[0116] According to a very particularly preferred embodiment, the sulfonic acid used in the context of the present invention is methanesulfonic acid (MSA) or anhydrous methanesulfonic acid (AMSA).

[0117] The said sulfonic acid may be supported or not. Preferably, it is not supported.

[0118] When the same is supported, it is possible, for example, to use sulfonated resins of the styrene-divinylbenzene copolymer type, for example Amberlyst® 15 or Nafion® resin.

[0119] For example, between 0.1 and 10 eq. of acid are used for a polythioester. Petition 870250083211, dated 09 / 16 / 2025, page 30 / 45 18 / 27

[0120] For example, between 3 and 60 eq. (molar equivalent), preferably between 3 and 20 eq., of alcohol are used for a polythioester.

[0121] The deprotection stage b) can be carried out at a temperature between 10°C and 100°C, preferably between 25°C and 80°C, more preferably between 40°C and 80°C. It is generally carried out at atmospheric pressure.

[0122] Stages a) and b) can be carried out in the same reactor. For example, a batch reactor can be used.

[0123] Subsequent stages of conventional recovery and / or conventional purification of the polythiol recovered at the conclusion of stage b) may be carried out, depending on the desired degree of purity. For example, when deprotection is carried out by the addition of a base, the reaction medium may subsequently be acidified and conversely, when deprotection is carried out by the addition of an acid, the reaction medium may be basified.

[0124] The resulting organic phase comprising the various thiols (in particular the polythiol and the (xl)thiols) can subsequently be extracted and optionally concentrated.

[0125] Thus, and in particular, the polythiol obtained may be in the form of a polyol composition as mentioned below. COMPOSITIONS ACCORDING TO THE INVENTION

[0126] When a polythiol is prepared from a terpene or from a terpene derivative having x C=C double bonds, the conversion of these double bonds into -SH functions is not usually complete and byproducts may be formed at each of the various stages, whatever process is used.

[0127] According to the invention, the term “polythiol” refers to the polythiol corresponding to the starting terpene or to the starting terpene derivative and comprising x -SH functions. In this case, the conversion of the initial x C=C double bonds into -SH functions is complete.

[0128] According to the invention, the term “(x-1)thiol” refers to a thiol corresponding to the starting terpene or the starting terpene derivative and comprising (x-1) -SH functions. The term “corresponding to the starting terpene or the starting terpene derivative” is understood to mean that the structure of the starting terpene or the starting terpene derivative and the (x-1)thiol obtained is Petition 870250083211, dated 09 / 16 / 2025, p. 31 / 45 19 / 27 identical, except for the x C=C double bonds, which were converted into (x-1) -SH functions. In this case, the conversion of C=C double bonds into -SH functions was not complete: one -SH function is lost.

[0129] The C=C double bond not converted to an -SH function may in particular be: - still in the form of a C=C double bond; or - in the form of a thioester function that has not been deprotected.

[0130] There may thus be different structures of (x-1)thiols, but they are here combined under this general name which distinguishes their number of -SH functions (unless specifically mentioned otherwise). Also included are (x-1)thiols that are positional isomers of the double bonds.

[0131] For example, during stage a), (xl)thioesters can be formed. In this case, for x starting C=C double bonds, only (x-1) C=C double bonds react with thiocarboxylic acid to form (x-1) thioester functions.

[0132] Furthermore, during stage b), it is also possible for the lack of protection not to be complete.

[0133] Thus, it is possible to form, according to the process according to the invention: - (x-1)thiols of the (xl)thioesters formed in stage a); and / or - (xl)thiols of polythioesters that are not completely unprotected.

[0134] It is thus possible to obtain a resulting polyol composition from a terpene or from a terpene derivative having x C=C double bonds, comprising: - the polythiol corresponding to said terpene or to said terpene derivative comprising x -SH functions; and - the thiol(s) corresponding to said terpene or to said terpene derivative comprising (x-1) -SH functions; with x as defined above.

[0135] Such a composition may optionally comprise other by-products or impurities (e.g. monothiols). Petition 870250083211, dated 09 / 16 / 2025, page 32 / 45 20 / 27

[0136] In particular, it is possible to obtain a trithiol composition from a terpene or from a terpene derivative having three C=C double bonds, said composition comprising: - the trithiol corresponding to said terpene; and - the dithiol(s) corresponding to said terpene.

[0137] In particular, it is possible to obtain a tetrathiol composition from a terpene or from a terpene derivative having four C=C double bonds, said composition comprising: - the tetrathiol corresponding to said terpene or said terpene derivative; and - the trithiol(s) corresponding to said terpene or to said terpene derivative.

[0138] Thus, the present invention relates to a polyol A composition obtained from a terpene or from a terpene derivative having x C=C double bonds, said composition comprising: - the polythiol corresponding to said terpene or to said terpene derivative comprising x -SH functions; and - the thiol(s) corresponding to said terpene or to said terpene derivative comprising (x-1) -SH functions, with x as defined above.

[0139] In particular, said composition A comprises 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, more preferably at least 90% by weight, for example at least 95% by weight, of said polythiol, with respect to the total weight of composition A.

[0140] In particular, said composition A comprises less than 40% by weight, preferably less than 30% by weight, more preferably less than 25% by weight, of said (x-1)thiol(ols), with respect to the total weight of said composition A.

[0141] Preferably, the weight ratio of composition A is between 1:1 and 20,000:1, for example between 1:1 and 10,000:1, preferably between 1:1 and Petition 870250083211, dated 09 / 16 / 2025, pages 33 / 45 21 / 27 1000:1, more preferably between 1:1 and 100:1 and even more preferably between 1:1 and 10:1, for example between 2:1 and 10:1.

[0142] The aforementioned weight ratio is the weight ratio: [polythiol corresponding to said terpene or terpene derivative comprising x -SH functions] / [thiol(ols) corresponding to said terpene or terpene derivative comprising (x-1) -SH functions].

[0143] In a very particularly preferred manner, said composition A is obtained from a terpene or a terpene derivative selected from myrcene, farnesene, squalene, isosqualene, humulene and dihydrofarnesene. POLITIOLS ACCORDING TO THE INVENTION

[0144] The present invention also relates to the trithiol resulting from dihydrofarnesene, the heptathiol resulting from isosqualene and the tetrathiol resulting from camphorene (i.e., the trithiol corresponding to dihydrofarnesene, the heptathiol corresponding to isosqualene and the tetrathiol corresponding to camphorene).

[0145] Preferably, said trithiol is dihydro-3-farnesene trithiol. Trithiol of Dihydrofarnesene can have positional isomers: [Chem 10] HjCx [Chem 11] h3c^ [Chem 12] Cl h3c^ [Chem 13] particularly being in the form of one of the following: SH ÇHj ÇH3 SH SH ch3 ch3 ch3 SH SH D Γ2, Hj CH3 CHj SH i SH π , e P3, and Petition 870250083211, dated 09 / 16 / 2025, pages 34 / 45 22 / 27

[0146] Said dihydrofarnesene trithiol can be obtained from a starting composition comprising at least 70% by weight of dihydrofarnesene, more preferably at least 80% by weight of dihydrofarnesene, with respect to the total weight of the composition. Preferably, said composition comprises at least 85% by weight of dihydrofarnesene, with respect to the total weight of farnesene, of all the partially hydrogenated compounds resulting from the hydrogenation of farnesene and farnesane present in said composition.

[0147] More specifically, said composition is a dihydro-3-farnesene trithiol composition obtained from Myralene 10®.

[0148] Isoesqualene heptathiol may in particular be in the form of one of its following positional isomers: [Chem 14] [Chem 15] [Chem 16] and P7, and [Chem 17] Petition 870250083211, dated 09 / 16 / 2025, pp. 35 / 45 23 / 27

[0149] The present invention also relates to polythiols resulting from β-carotene, lycopene, farnesol, retinol, retinal, vitamin A, nerolidol, isomircenol and ipsdienol.

[0150] These compounds are novel and form part of the present invention.

[0151] The present invention also relates to the compositions as defined above and capable of being obtained, obtained or directly obtained by the process according to the invention. Likewise for the polythiols as defined above, which may be capable of being obtained, obtained or directly obtained by the process according to the invention. Description of the figures

[0152] Figure 1: Myrcene isomers

[0153] It is understood that, unless a specified isomer is mentioned, the name of a compound includes all of its possible positional isomers.

[0154] The following examples are given by way of illustration and do not limit the present invention. EXAMPLES: Example 1: Trithiol of dihydro-P-farnesene obtained from Myralene 10®, process according to the invention.

[0155] Stage a):

[0156] 48.7 g (0.64 mol) of TAA are introduced into a 250 ml jacketed reactor. The medium is stirred at 5°C. Air is bubbled into the reaction medium through a frit at a flow rate of approximately 0.4 Sl / h and nitrogen is passed over the free top of the reactor at a flow rate of approximately 4 Sl / h. Petition 870250083211, dated 09 / 16 / 2025, pages 36 / 45 24 / 27

[0157] 40 g (0.19 mol) of Myralene 10® are subsequently added dropwise using a peristaltic pump over approximately 27 min. Once the addition is complete, 35.7 g (0.77 mol) of EtOH are added to the reaction medium.

[0158] The reaction medium is kept stirred at 5°C overnight.

[0159] A GC / FID analysis shows the complete conversion of Myralene 10.

[0160] The air supply is cut off.

[0161] Stage b) of basic lack of protection:

[0162] 26.8 g (0.58 mol) of EtOH are then added to the reaction medium. The reaction medium is subsequently degassed with nitrogen for 1 h, then cooled to approximately 10°C and 103 g (0.64 mol) of a 25% sodium hydroxide solution, previously degassed, are added over 38 min using a dropping funnel. The reaction medium is left to stir under nitrogen at 10°C overnight and then at 25°C for 6 h.

[0163] A GC / FID analysis shows complete conversion of trithioacetate.

[0164] Recovery stage:

[0165] The reaction medium is subsequently cooled to 20°C and 117 g (0.64 mol) of 20% HCl (previously degassed with nitrogen) are then added dropwise to the reaction medium using a peristaltic pump. The trithiol phase is removed. The aqueous phase is extracted three times with 16.5 g (0.19 mol) of dichloromethane.

[0166] The organic phases are combined, then washed four times with 7 g (0.39 mol) of water and then concentrated in a rotary evaporator.

[0167] A composition comprising 82.29% by weight of dihydro-β-farnesene trithiol and 9.71% by weight of dihydro-p-farnesene dithiol is obtained (with respect to the total weight of the composition).

[0168] The ratiopolitio1, in weight is 82.29:9.71, that is, 8.5:1.

[0169] Example 2: Myrcene trithiol, process according to the invention

[0170] Stage a):

[0171] 64.5 g (0.85 mol) of TAA are introduced into a 250 ml jacketed reactor. The medium is stirred at 5°C and then 5.9 g (0.13 mol) of EtOH are rapidly added. Air is bubbled into the medium. Petition 870250083211, dated 09 / 16 / 2025, pages 37 / 45 25 / 27 reaction by means of a frit at a flow rate of approximately 0.4 Sl / h nitrogen is passed into the free top of the reactor at a flow rate of approximately 4 Sl / h.

[0172] 35 g (0.26 mol) of myrcene are subsequently added dropwise using a peristaltic pump over approximately 22 min. Once the addition is complete, 23.7 g (0.51 mol) of EtOH are added to the reaction medium.

[0173] The reaction medium is kept stirred at 5°C overnight.

[0174] A GC / FID analysis shows complete conversion of myrcene.

[0175] The air supply is cut off.

[0176] Stage b) of basic lack of protection:

[0177] 82.9 g (1.80 mol) of EtOH are then added to the reaction medium. The reaction medium is subsequently degassed with nitrogen for 1 h, then heated to approximately 30°C and 73.7 g (0.85 mol) of a previously degassed 46% sodium hydroxide solution are added using a dropper funnel. The reaction medium is stirred under nitrogen at 40°C for 21 h.

[0178] A GC / FID analysis shows complete conversion of trithioacetate.

[0179] Recovery stage:

[0180] The reaction medium is subsequently cooled to 20°C and 154.6 g (0.85 mol) of 20% HCl (previously degassed with nitrogen) are then added dropwise to the reaction medium using a peristaltic pump. The trithiol phase is removed. The aqueous phase is extracted three times with 21.8 g (0.26 mol) of dichloromethane.

[0181] The organic phases are combined, then washed four times with 9.2 g (0.51 mol) of water and then concentrated in a rotary evaporator.

[0182] A composition comprising 50.56% by weight of myrcene trithiol and 23.6% by weight of myrcene dithiol is obtained (with respect to the total weight of the composition).

[0183] The ratiopolitio1 in weight is 50.56:23.6, that is, 2.1:1. 1 J(x—l)tioi(óis)r

[0184] Example 3: Tetrathiol obtained from farnesene, process according to the invention Petition 870250083211, dated 09 / 16 / 2025, pages 38 / 45 26 / 27

[0185] Stage a):

[0186] 163.9 g (2.15 mol) of TAA are introduced into a 1 liter jacketed reactor. The medium is stirred at 5°C and then 23.0 g (0.50 mol) of EtOH are rapidly added. Air is bubbled into the reaction medium through a frit at a flow rate of approximately 0.4 Sl / h and nitrogen is passed over the free top of the reactor at a flow rate of approximately 4 Sl / h.

[0187] 100 g (0.49 mol) of farnesene, sold under the trade name Biofene®, are subsequently added dropwise using a peristaltic pump over approximately 47 min. Once the addition is complete, 90.1 g (1.96 mol) of EtOH are added to the reaction medium.

[0188] The reaction medium is kept stirred at 5°C overnight.

[0189] A GC / FID analysis shows the complete conversion of farnesene and its reaction intermediates.

[0190] The air supply is cut off.

[0191] Stage b) of basic lack of protection:

[0192] The reaction medium is subsequently degassed with nitrogen for 1 h, then cooled to approximately 10°C and 187.2 g (2.15 mol) of a previously degassed 46% sodium hydroxide solution are added over 35 min using a dropper funnel. The reaction medium is stirred under nitrogen at 25°C for 19 h.

[0193] A GC / FID analysis shows complete conversion of tetrathioacetate.

[0194] Recovery stage:

[0195] The reaction medium is subsequently cooled to 20°C and 294.4 g (1.61 mol) of 20% HCl (previously degassed with nitrogen) are then added dropwise to the reaction medium using a peristaltic pump. The tetrathiol phase is removed. The aqueous phase is extracted three times with 41.6 g (0.49 mol) of dichloromethane.

[0196] The organic phases are combined, then washed four times with 17.6 g (0.98 mol) of water and then concentrated in a rotary evaporator. Petition 870250083211, dated 09 / 16 / 2025, pages 39 / 45 27 / 27

[0197] A composition comprising 61.24% by weight of farnesene tetrathiol and 25.77% by weight of farnesene trithiol is obtained (with respect to the total weight of the composition).

[0198] The ratiopolitio1—by weight is 61.24: 25.77, that is, 2.4:1. 1 J(xl)tiol( pis)r

Claims

1. A process, characterized by being for the preparation of a polythiol comprising the following stages: a) a terpene or a terpene derivative is reacted with a thiocarboxylic acid in the presence of oxygen (O2) and at least one organic solvent, so as to obtain a reaction medium comprising a polythioester and said at least one organic solvent; and b) a deprotection stage of the polythioester obtained in stage a) is carried out, so as to obtain a polythiol; wherein stage a) and stage b) are carried out in a single-vessel synthesis.

2. Preparation process according to claim 1, characterized in that the deprotection stage b) is a basic deprotection, preferably carried out by the addition of an alkaline hydroxide.

3. Process according to claim 1, characterized in that the deprotection stage b) is an acid deprotection, preferably in the presence of an alcohol.

4. A preparation process according to any of the preceding claims, characterized in that said organic solvent is chosen from the group consisting of: alcohols, ethers, organochlorine solvents, carboxylic acids and mixtures thereof.

5. Preparation process according to any of the preceding claims, characterized in that the organic solvent is chosen from among alcohols of the following general formula (IV): R4-OH (IV) wherein R4 represents a saturated, linear, branched or cyclic hydrocarbon radical comprising from 1 to 10, preferably from 1 to 4, carbon atoms.

6. A preparation process according to any one of the preceding claims, characterized in that the thiocarboxylic acid is thioacetic acid.

7. Preparation process according to any of the preceding claims, characterized in that said terpene or terpene derivative is chosen from the group consisting of myrcene, farnesene, squalene, isosqualene, humulene and dihydrofarnesene.

8. Polyol composition A, characterized in that it is obtained from a terpene or from a terpene derivative having x C=C double bonds, said composition comprising: - the polythiol corresponding to said terpene or said terpene derivative comprising x -SH functions; and - the thiol(s) corresponding to said terpene or said terpene derivative comprising (x-1) -SH functions; with x being an integer greater than or equal to 3.

9. Polyol A composition according to claim 8, characterized in that the ratio, p0lltl0^, by weight is between 1:1 and 50,000:1, r (xl)thioí(ols) preferably between 2:1 and 50,000:

1.

10. Polyol A composition according to claim 8 or 9, characterized in that said terpene or terpene derivative is chosen from the group consisting of myrcene, farnesene, squalene, isosqualene, humulene and dihydrofarnesene.

11. Polythiol, characterized by being chosen from trithiol obtained from dihydrofarnesene, heptathiol obtained from isosqualene, and tetrathiol obtained from camphorene.

12. Polythiol according to claim 11, characterized in that it has one of the following formulas: SH SH CH3 ch3 ch3 H3C SH SH Petition 870250083211, dated 09 / 16 / 2025, page. 42 / 45 3 / 3 ch3 ch3 ch3 SH SH ' ch3 ch3 ch: h3c SH SH SH ^SH ÇHj CH3 < SH SH SH .SH CHí CH3 < HjC^Y^^-^Y χ / \γ' SH SH SH çh3 çh3 ch3 SH SH SH SH ch3 ch3 > 1 1 hsU H3C''^Y'~'''^^y'''^^ SH SH ch35H P3, í ^CH3 P4 SH SH u J CH3 CH3 HS Ps, SH CH3 CHi SH Fr.

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