POLYOLS ALCOXYLÉS

Abstract

ALKOXYLATED POLYOLS The present invention relates to an alkoxylated polyol with a carboxylic acid function, with a molar mass by weight greater than or equal to 2000 Dalton. The invention also relates to the use of said alkoxylated polyol with a carboxylic acid function as a solvent, surfactant or synthesis reagent for the preparation of organic compounds, and in particular for the preparation of polymers. Fig.: none

Description

Title of the invention: ALKOXYLATED POLYOLS

[0001] The present invention relates to alkoxylated polyols, in particular acid-functional alkoxylated polyols, and more particularly to bio-sourced, acid-functional alkoxylated polyols of high molecular weight. The invention also relates to the process for preparing such high molecular weight carboxylic acid-functional alkoxylated polyols.

[0002] The chemical industry has been using organic molecules carrying two, three, four, five, or even more hydroxyl functions, commonly referred to as "polyols," for many years. Such polyols are widely used for a multitude of applications as diverse as they are varied, for example, and without wishing to be limiting, as such as solvents, surfactants, but also as synthetic reagents for the preparation of polyesters, polyurethanes, poly(meth)acrylates, and others.

[0003] The polyols commonly used today are polyols of more or less high molecular weight, with more or less significant functionalities (number of hydroxyl functions per polyol molecule), of variable viscosity, depending on the applications for which they are intended.

[0004] Patent applications EP3523357, EP3523358 and US20200032002 describe processes for alkoxylating lignin, in order to obtain alkoxylated polyols. These polyols are thus derivatives of bio-sourced products, having numerous hydroxyl functions, without carboxylic acid functions or only a few carboxylic acid functions, and most often in a very small number compared to the number of hydroxyl functions. Polyoxyethylene ether esters derived from bio-sourced products are also known, which are described for example in application CN104402720; however, these compounds do not have a carboxylic acid function.

[0005] Patent application US2023070697 describes the reaction of polyether polyols with cyclic anhydrides to form polyether diacids, which can in turn be alkoxylated to polyetherester diols. The polyols do not have a carboxylic acid function.

[0006] Patent application CN104356030 describes a process for preparing sulfates or sulfonates of alkoxylated methyl esters of castor oil. The polyols described in this application do not contain a carboxylic acid function.

[0007] Patent application EP4177285 describes polyol compositions comprising a first polyol of low molar mass, a second polyol of high molar mass, said polyols being placed in the presence of a non-alkoxylated diol with a carboxylic function to produce ionic silylated copolyurethanes.

[0008] Alkoxylated polyols with a molecular weight of between 1000 Dalton and 10000 Dalton are described in application WO2017204509. The number of hydroxyl functions (-OH) corresponding to primary alcohol functions represents from 50% to 90% by weight relative to the total number of hydroxyl functions in the polyol. These polyols do not include a carboxylic acid function.

[0009] The work of Paula Mazo et al. (“Kinetics of the Transesterification of Castor Oil with Maleic Anhydride Using Conventional and Microwave Heating”, J Am Oil Chem Soc, (2012), DOI 10.1007 / sl 1746-012-2020-3) presents castor oil derivatives in which one of the hydroxyl functions is subjected to an esterification reaction with maleic anhydride. The resulting carboxylic-functional diol, however, has a relatively low molar mass.

[0010] The various compounds of the prior art described above each suffer from at least one drawback, either that they are derived exclusively from petroleum-sourced raw materials, or that they have excessively high solidification points, or that they have an unsuitable viscosity, or that they are not or only slightly hydrophilic.

[0011] The present invention aims to provide polyols with a carboxylic acid function which do not have the drawbacks encountered with the products known from the prior art. Indeed, the polyols used today need to be increasingly efficient and more environmentally friendly.

[0012] More specifically, the present invention provides high molecular weight carboxylic acid functional alkoxylated polyols, and in particular high molecular weight carboxylic acid functional alkoxylated polyols derived from bio-sourced, available and inexpensive raw materials, and more particularly still high molecular weight carboxylic acid functional alkoxylated polyols whose hydrophilicity is suitable for the applications for which they are intended. As other objectives, the present invention aims to provide high molecular weight carboxylic acid functional alkoxylated polyols having a low solidification point and low viscosity. Still other objectives will become apparent in the description of the invention which follows.

[0013] The applicant has now discovered that the above-mentioned objectives are achieved in whole or at least in part thanks to the present invention which is now presented in the detailed description which follows.

[0014] Unless otherwise indicated, all ranges of values ​​described in the following description, for example "from ... to ....", "between .... and ..." and others, are understood to include limits.

[0015] Thus, a first object of the present invention consists of an alkoxylated polyol with a carboxylic acid function, the molar mass of which is greater than or equal to 2000 Dalton, preferably greater than or equal to 2300 Dalton, advantageously greater than or equal to 2500 Dalton, and more specifically greater than or equal to 3000 Dalton. The Dalton is defined as equal to one twelfth of the mass of a carbon 12 atom, and is another name for the unified atomic mass unit, symbol "u", used to express the mass of atoms and molecules. The molar mass expressed in the present application is a molar mass by weight (Mw) which can be determined by gel permeation chromatography (GPC), in particular using polystyrene standards, according to techniques well known to those skilled in the art and in particular according to a protocol described in the examples illustrating the invention and described later.

[0016] By polyol is meant a compound comprising more than one hydroxyl function per molecule, that is to say two, three, four, five or more hydroxyl functions per molecule, preferably two, three, four or five hydroxyl functions per molecule, more preferably two, three or four hydroxyl functions per molecule, for example two or three hydroxyl functions per molecule, and according to one embodiment of the invention two hydroxyl functions per molecule.

[0017] More precisely, the alkoxylated polyol with a carboxylic acid function according to the invention has a functionality f(OH) strictly greater than 1.0, preferably between 1.2 and 5, more preferably between 1.2 and 4, advantageously between 1.2 and 3, where f(OH) represents the average number of hydroxyl groups per molecule of polyol.

[0018] The functionality f(OH) of a polyol can be determined according to any method well known to those skilled in the art and for example by measuring its i0H, as described below. Said functionality f(OH) can then be calculated as follows: f(OH)= (iOH *Mpoiyoi) / 56100, where i0H is the hydroxyl number in mg KOH / g of the polyol and Mpoiyoi is the weight average molecular mass of the polyol, expressed in Dalton.

[0019] The expression "alkoxylated polyol" indicates that the polyol is a polyether polyol, in particular a polyol comprising from 2 to 100 alkyleneoxy units per molecule, more particularly from 4 to 90 alkyleneoxy units per molecule, more specifically from 10 to 80 alkyleneoxy units per molecule, advantageously from 20 to 60 alkyleneoxy units per molecule, better still from 30 to 50 alkyleneoxy units per molecule.

[0020] By alkyleneoxy unit is preferably meant a unit chosen from ethyleneoxy, propyleneoxy and butyleneoxy units, preferably from ethyleneoxy and propyleneoxy units. In the compound of the present invention, the alkyleneoxy units may of course be identical or different. In a preferred embodiment, the alkyleneoxy units (or alkoxylated units) are identical in the compound of the invention. Compounds comprising units ethylene-oxy and / or propylene-oxy, and more preferably the alkylene-oxy units of the compound of the present invention are ethylene-oxy units.

[0021] In a preferred embodiment, the alkoxylated polyol of the invention has a hydroxyl number (iOH) most often between 5 mgKOH / g and 75 mgKOH / g, preferably between 10 mgKOH / g and 60 mgKOH / g, more preferably between 20 mgKOH / g and 60 mgKOH / g, more preferably between 30 mgKOH / g and 60 mgKOH / g. The hydroxyl number (ion), measured by potentiometry, is the number of milligrams of potassium hydroxide necessary for the neutralization of the acetic acid necessary to acetylate 1 g of the hydroxyl-functional compound, or number of milligrams of potassium hydroxide corresponding to the hydroxyl functions in 1 g of the compound, as described in ISO 4326:1980(fr).

[0022] In another preferred embodiment, the alkoxylated polyol of the invention has an acid number (icoou) most often between 5 mgKOH / g and 50 mgKOH / g, preferably between 10 mgKOH / g and 40 mgKOH / g, more preferably between 15 mgKOH / g and 35 mgKOH / g. The acid number (icoou) is also measured by potentiometry and represents the number of milligrams of potassium hydroxide necessary to neutralize the free acidity contained in one gram 1 g of the compound.

[0023] Among the alkoxylated polyols with a carboxylic acid function of the invention, those whose iOH / icooH ratio is between 0.5 and 6 are particularly preferred, preferably whose iOH / icooH ratio is between 1 and 4.

[0024] In yet another preferred embodiment, the alkoxylated polyol of the invention has a viscosity ranging from 200 mPa.s to 1500 mPa.s measured at 25°C, preferably from 400 mPa.s to 1200 mPa.s measured at 25°C, more preferably from 500 mPa.s to 1100 mPa.s measured at 25°C. The viscosity values ​​mentioned in the present description are dynamic viscosity values ​​measured according to techniques well known to those skilled in the art, and in particular according to the requirements of standard DIN 53019 using a viscometer of the Rheomat RM180 type from Lamy Rheology Instruments.

[0025] The alkoxylated polyol of the present invention most often has a relatively low melting point, most often between 0°C and 50°C, preferably between 0°C and 30°C, preferably between 0°C and 20°C, better still between 5°C and 20°C. The melting point is measured according to any method well known to those skilled in the art.

[0026] The carboxylic acid-functional alkoxylated polyol of the present invention may be prepared according to any method well known to those skilled in the art. By way of non-limiting example, the carboxylic acid-functional alkoxylated polyol of the invention may be prepared according to a process comprising, and preferably consisting of, the following steps: a) providing a polyol, preferably a bio-sourced polyol, b) alkoxylation of said polyol, c) reaction of the alkoxylated polyol obtained in step b) with a carboxylic acid anhydride, d) recovery of the carboxylic acid functional alkoxylated polyol of the present invention.

[0027] By polyol is meant any compound comprising at least two hydroxyl functions per molecule. In a preferred embodiment, the alkoxylated polyol with a carboxylic acid function of the present invention is derived from a bio-sourced polyol. Examples of bio-sourced polyols that can be used in step a) above are chosen from sugars, alkylpolyglycosides, polyphenols, lignins, polyhydroxylated natural oils, and in particular vegetable or animal oils, and mixtures of two or more of them. It should be understood that the polyol provided in step a) is a non-alkoxylated polyol.

[0028] The bio-sourced polyol that can be used in step a) above can be directly in the form of a plant resource (for example a glyceride of fatty acid(s), this plant resource possibly having been modified prior to step a). By way of non-limiting example, one or more hydroxyl functions can be introduced onto the fatty acid chains, according to any method well known to those skilled in the art, and in particular by epoxidation of double bond(s) and opening of the epoxide formed.

[0029] According to one embodiment of the invention, the non-alkoxylated polyol used in step a) is a bio-sourced polyol, and more particularly a glyceride of fatty acid(s). In a preferred embodiment, the non-alkoxylated polyol used in step a) may be castor oil and / or a hydroxylated vegetable oil, said vegetable oil being able, for example, to be soybean oil, rapeseed oil, corn oil, cottonseed oil, linseed oil, olive oil, sesame oil, walnut oil, sunflower oil, acorn oil (for example cork oak), tall oil, safflower oil, grape oil, etc. A vegetable oil is said to be "hydroxylated" when it has been modified to introduce hydroxyl groups onto the fatty acid chains of the glycerides. The hydroxyl group may be directly or indirectly, preferably directly, linked to a carbon atom of the fatty acid chain.For example, when the hydroxyl group is indirectly linked, it may have been introduced by double bond hydroformylation / hydrogenation.

[0030] In a preferred embodiment, the alkoxylated polyol of step a) is a biosourced polyol comprising at least one carboxylic ester function, and more preferably the polyol of step a) is chosen from vegetable oils, and by way of examples non-limiting examples among castor oil, palm oil, tall oil (or "tall oil" in English), as well as mixtures of two or more of them. In a very particularly preferred embodiment, the bio-sourced polyol used in step a) is castor oil.

[0031] The alkoxylation reaction of the polyol of step b) can be carried out according to any method well known to those skilled in the art. The most commonly implemented method, for obvious reasons of industrial feasibility and cost savings, is a catalytic alkoxylation reaction of the polyol in the presence of at least one alkylene oxide.

[0032] The catalyst used in this alkoxylation step can be of any type and is well known to those skilled in the art, and preferably the catalyst is chosen from alkali metal hydroxides, sodium or potassium alcoholates, tertiary amines chosen from trialkylamines and tetramethylguanidine, or DMC ("Double Metal Cyanide" type catalysts). Preferably the catalyst is a basic catalyst, advantageously chosen from alkali metal hydroxides.

[0033] At the end of this alkoxylation step b), an alkoxylated polyol is obtained, such as for example an alkoxylated castor oil, and more particularly an ethoxylated castor oil. The alkoxylated chains are thus carried by the oxygen atoms of the hydroxyl functions present in the starting polyol.

[0034] The alkoxylated polyol is then reacted with a carboxylic acid anhydride, preferably a cyclic carboxylic acid anhydride (step c)). This reaction can also be easily carried out according to any method well known to those skilled in the art. At least one hydroxyl function of the alkoxylated polyol of step b) can thus react in the presence of a carboxylic acid anhydride to form an ester function combined with a carboxylic acid function. By varying the amounts of alkoxylated polyol on the one hand and of carboxylic acid anhydride on the other hand, it is possible to functionalize at least one hydroxyl function of the alkoxylated polyol or several hydroxyl functions of said alkoxylated polyol.

[0035] This reaction is carried out according to any method well known to those skilled in the art and may, for example, be carried out by adding a carboxylic anhydride to the alkoxylated polyol resulting from step b), with stirring and heating, for example at a temperature of between 50°C and 100°C, preferably between 60°C and 120°C, more preferably between 80°C and 100°C, for a period of time which may vary from a few minutes to a few hours. This reaction is preferably carried out under anhydrous conditions, and most often at atmospheric pressure or under slight depression or slight overpressure.

[0036] The carboxylic acid anhydride used in step c) may be of any type well known to those skilled in the art. Cyclic anhydrides are however preferred so that the anhydride reacting with a hydroxyl function of the alkoxylated polyol forms on the one hand an ester function and on the other hand a free carboxylic acid function.

[0037] As non-limiting examples, the cyclic anhydride may be chosen from itaconic anhydride, citraconic anhydride, maleic anhydride, dimethylmaleic anhydride, succinic anhydride, 2,3-dimethylsuccinic anhydride, octenylsuccinic anhydride, decenylsuccinic anhydride, dodecenylsuccinic anhydride (for example, branched olefin chain isomers (CAS RN 26544-38-7), or n-dodecenylsuccinic anhydride (CAS RN 19780-11-1), tetradecenylsuccinic anhydride, hexadecenylsuccinic anhydride, octadecenylsuccinic anhydride, eicosenylsuccinic anhydride, glutaric anhydride (or pentanedioic anhydride), 2,4-dimethylglutaric anhydride, 3,3-dimethylglutaric anhydride, 3-dimethylglutaric anhydride, adipic anhydride, glycolic anhydride, cis-aconitic anhydride, 2-(2'-carboxyethyl)maleic anhydride, 1-methyl-2-(2'-carboxyethyl)maleic anhydride, phenylsuccinic anhydride,S-acetylmercaptosuccinic anhydride, hexahydrophthalic anhydride, 1,2-cyclopentanedicarboxylic anhydride, 1,2-cyclobutanedicarboxylic anhydride, phthalic anhydride, homophthalic anhydride, trimellitic anhydride, diphenic anhydride, camphoric anhydride, nadic anhydride, methylnadic anhydride, and mixtures of two or more of them in any proportions.

[0038] In a particularly preferred embodiment, the carboxylic acid anhydride is chosen from butanedioic anhydride (succinic anhydride), butenedioic anhydride (maleic anhydride), pentanedioic anhydride, glutaric anhydride, adipic anhydride, camphoric anhydride, phthalic anhydride, diphenic anhydride and their substituted derivatives and in particular their alkenyl derivatives. Particularly preferred are succinic anhydride and maleic anhydride, as well as their substituted derivatives, in particular their alkenyl derivatives, more particularly succinic anhydride as well as its substituted derivatives, in particular its alkenyl derivatives.

[0039] By substituted derivatives is meant that at least one of the hydrogen atoms of the carboxylic acid anhydride is substituted by an organic radical, said organic radical preferably being a hydrocarbon chain comprising from 1 to 30 carbon atoms, preferably from 2 to 25 carbon atoms, more preferably from 3 to 22 carbon atoms, in a linear or branched chain, optionally comprising one or several unsaturations in the form of double bond(s) and / or triple bond(s) and or saturated or partially or totally unsaturated cycle(s).

[0040] Very particularly preferred examples of carboxylic acid anhydride which can be used in the context of the present invention include succinic anhydride, maleic anhydride and alkenyl succinic anhydrides, in particular succinic anhydrides substituted by a hydrocarbon chain of formula (CnH2n_i), where n represents an integer of between 1 and 30 carbon atoms, preferably between 2 and 25 carbon atoms, more preferably between 3 and 22 carbon atoms. According to a particularly preferred embodiment, the carboxylic acid anhydride is chosen from alkenyl succinic anhydrides also called ASA, particularly suitable representatives of which are chosen from (allyl) succinic anhydride, (dodecenyl) succinic anhydride, (octadecyl) succinic anhydride, (tetrapropenyl) succinic anhydride, to name only the most common ASA anhydrides.

[0041] A very particularly preferred example of alkoxylated polyol with a carboxylic acid function according to the invention is an alkoxylated castor oil modified by an (alkenyl) succinic anhydride and having a molecular weight greater than or equal to 2000 Dalton, better still greater than or equal to 2300 Dalton, better still greater than or equal to 2500 Dalton and preferably greater than 3000 Dalton.

[0042] The alkoxylated polyol with a carboxylic acid function thus obtained is recovered from the reaction medium, according to conventional methods well known to those skilled in the art, which may comprise, in a non-limiting manner, one or more washing, separation, drying, and other operations.

[0043] The alkoxylated polyol with a carboxylic acid function according to the invention is a compound comprising two or more hydroxyl functions, several alkoxylated units, and at least one carboxylic acid function, preferably a carboxylic acid function. The alkoxylated polyol with a carboxylic acid function according to the invention can therefore be considered as a multifunctional polyol, the latter preferably having a relatively low melting point, and most often a multifunctional polyol which is liquid at room temperature. In addition, this multifunctional polyol can advantageously be prepared from oil of natural, vegetable or animal origin, which makes the alkoxylated polyol with a carboxylic acid function according to the invention a biosourced multifunctional polyol which is liquid at room temperature.

[0044] In yet another preferred embodiment, the carboxylic acid-functional alkoxylated polyol is a fatty chain triester comprising on the one hand two terminal hydroxyl functions each carried by an alkoxylated chain and on the other hand a carboxylic acid function linked by an ester function to the alkoxylated polyol. Preferred carboxylic acid-functional alkoxylated polyols are diols prepared from oil of ethoxylated castor oil, with a total number of ethoxylated units of between 20 and 60, preferably between 30 and 50 units per molecule, and comprising a carboxylic acid function linked by an ester function to the alkoxylated castor oil.

[0045] As indicated previously, one of the advantages of these alkoxylated polyols with a carboxylic acid function is that they are high molecular weight polyols and that they are derived from bio-sourced raw materials, and are therefore more environmentally friendly.

[0046] Another advantage of the multifunctional polyol according to the invention is the variability of its hydrophilic / hydrophobic character depending on the number and nature of the alkoxylated units and the number of hydroxyl and carboxylic acid functions. For example, the presence of ethoxylated units, for example between 20 and 60 ethoxylated units per molecule, makes it possible to make the compound of the invention more hydrophilic and thus facilitate the solubilization, or at least the compatibility, of the compound of the invention in the applications for which it is intended.

[0047] The solubilization / compatibility properties can also be adjusted, or even optimized depending on the nature of the carboxylic anhydride used to graft the carboxylic acid function. Very interesting properties have been observed for alkoxylated polyols, and in particular ethoxylated polyols, and for which the carboxylic acid function has been provided by a succinic anhydride, and preferably by a succinic anhydride substituted by a hydrocarbon chain of formula CnH2n i, where n is an integer between 2 and 30, preferably between 2 and 20.

[0048] According to another object, the present invention relates to the use of the alkoxylated polyol with a carboxylic acid function as described above as a solvent, surfactant, or even as a synthesis reagent for the preparation of organic compounds, and in particular for the preparation of polymers such as for example for the preparation of polyesters, polyurethanes, poly(meth)acrylates and others.

[0049] It is also possible to envisage the use of the acidic alkoxylated polyol of the invention as a solvent in processes for the alkoxylation of polyphenols, as well as the use of the alkoxylated polyphenol as defined above as a solvent in processes for the alkoxylation of polyphenols.

[0050] As indicated above, and more specifically, the invention relates to the use of the carboxylic-functional alkoxylated polyol according to the invention as nonionic or anionic surfactants, as bio-sourced precursors of carbon fiber or for manufacturing polymers, for example polyurethanes, polyesters, poly(meth)acrylates and others. It is also conceivable to use the alkoxylated polyol defined above to synthesize other organic compounds, usable as such or as synthesis reagents.

[0051] The carboxylic-functional alkoxylated polyol according to the invention has proven particularly interesting in reaction with diisocyanates and amino-alkoxysilanes for the synthesis of silane-terminated polyurethanes. Such silane-terminated polyurethanes are used in particular in adhesives, sealants and coatings for the aeronautical, automotive or construction industries. The multifunctional polyol prepared from bio-sourced material according to the invention makes it possible in particular to manufacture silane-terminated polyurethanes with remarkable application performances, in particular in parquet adhesives.

[0052] The present invention now makes it possible to have an alkoxylated polyol with a carboxylic function which can be adapted to a wide variety of applications, in particular because it can advantageously be prepared from raw materials of renewable origin.

[0053] Furthermore, the number and nature of the alkoxylated units gives the polyol controlled properties in terms of hydrophilicity and hydrophobicity. The alkoxylated polyol with a carboxylic acid function can also be considered as a multifunctional polyol with a high molar mass, in particular when the number of alkoxylated units is large, for example more than 20 and better still from 30 to 50. In this case, the multifunctional polyol of the invention is a polyol with a polyether skeleton with a molar mass greater than or equal to 2000 Dalton g / mol which falls into the category of macromolecules.

[0054] As already indicated previously, despite its high molar mass, the alkoxylated polyol with carboxylic acid function according to the invention retains a relatively low viscosity and a low solidification point. The polyol of the invention is thus easily handled at room temperature.

[0055] The following examples are given solely for the purpose of illustrating the present invention, without the intention of limiting the scope thereof which is defined by the appended claims. Examples

[0056] Example of synthesis of an ethoxylated castor oil with a carboxylic acid function

[0057] In a 4-liter glass reactor equipped with mechanical stirring, heating by a heating mantle, a nitrogen inerting system and a dropping funnel, 3312 g of Surfaline® R40 ethoxylated castor oil supplied by Arkema are introduced. The contents of the flask are heated to 90°C, then 408.5 g of (tetrapropenyl)succinic anhydride (CAS RN 26544-38-7, K12 from Vertellus LLC) are added over 1 hour while maintaining the temperature at 90°C. After 4 hours of stirring at 90°C the product is cooled and drained.

[0058] The alkoxylated polyol with a carboxylic acid function thus obtained has a hydroxyl number i0H equal to 46 mgKOH / g, an acid number icoou equal to 22 mgKOH / g, with an average number of ether functions (i.e. ethoxy units) equal to 40 ethoxy units per molecule. The measured viscosity is 785 mPa.s at 25°C. The melting point of the product obtained is 10°C, and its weight-average molar mass is 3300 Dalton.

[0059] The weight average molecular mass (Mw) of the obtained compound was determined by gel permeation chromatography (GPC) with polystyrene standards, using the equipment and conditions indicated below: • System: Waters Alliance GPC, • Columns: one 5 pm precolumn (50*7.8 mm), one 103 Â column (300*7.8 mm) (Phenomenex reference 00H-0444-KO), two 104 Â columns (300*7.8 mm) (Phenomenex reference 00H-0445-KO), one Shodex F6028050 column (GPC-KF-805), • Eluent: tetrahydrofuran, • Flow rate: 1 mL / min, • Temperature: 35°C, • Injection volume and sample concentration: 50 pL, 10 mg / mL, • Detector: UV at 254 nm, refractive index.

Claims

Claims

1. Alkoxylated polyol with carboxylic acid function, with a molar mass greater than or equal to 2000 Dalton, preferably greater than or equal to 2300 Dalton, advantageously greater than or equal to 2500 Dalton, and more specifically greater than or equal to 3000 Dalton.

2. Polyol according to claim 1, comprising two, three, four or five hydroxyl functions per molecule, preferably two, three or four hydroxyl functions per molecule, advantageously two or three hydroxyl functions per molecule.

3. Polyol according to claim 1 or claim 2, comprising from 2 to 100 alkyleneoxy units per molecule, more particularly from 4 to 90 alkyleneoxy units per molecule, more specifically from 10 to 80 alkyleneoxy units per molecule, advantageously from 20 to 60 alkyleneoxy units per molecule, better still from 30 to 50 alkyleneoxy units per molecule.

4. Polyol according to any one of the preceding claims, in which the alkoxylated units are ethyleneoxy and / or propyleneoxy units, and preferably the alkoxylated units are ethyleneoxy units.

5. Polyol according to any one of the preceding claims, with a hydroxyl number, measured by potentiometry, of between 5 mgKOH / g and 75 mgKOH / g, preferably of between 10 mgKOH / g and 60 mgKOH / g, more preferably of between 20 mgKOH / g and 60 mgKOH / g, more preferably of between 30 mgKOH / g and 60 mgKOH / g.

6. Polyol according to any one of the preceding claims, with an acid number, measured by potentiometry, of between 5 mgKOH / g and 50 mgKOH / g, preferably of between 10 mgKOH / g and 40 mgKOH / g, more preferably of between 15 mgKOH / g and 35 mgKOH / g.

7. Polyol according to any one of the preceding claims, the viscosity of which ranges from 200 rnPa.s to 1500 mPa.s measured at 25°C, preferably from 400 rnPa.s to 1200 mPa.s measured at 25°C, more preferably from 500 mPa.s to 1100 mPa.s measured at 25°C.

8. Polyol according to any one of claims 1 to 6, the melting point of which is between 0°C and 50°C, preferably between 0°C and 30°C, preferably between 0°C and 20°C, better still between 5°C and 20°C.

9. A process for preparing the polyol according to any one of the preceding claims comprising, and preferably consisting of, the following steps: a) providing a non-alkoxylated polyol, preferably a non-alkoxylated bio-sourced polyol, b) alkoxylation of said polyol, c) reaction of the alkoxylated polyol obtained in step b) with a carboxylic acid anhydride, d) recovery of the carboxylic acid-functional alkoxylated polyol of the present invention.

10. Method according to claim 9, in which the polyol of step a) is a biosourced polyol comprising at least one carboxylic ester function, and more preferably the polyol of step a) is chosen from vegetable oils, advantageously from castor oil, palm oil, tall oil, as well as mixtures of two or more of them.

11. Use of a polyol according to any one of claims 1 to 9, as solvent, surfactant, synthesis reagent for the preparation of organic compounds, and in particular for the preparation of polymers.

12. Use according to claim 11, for the preparation of polyurethanes with silane terminations.

13. Use according to claim 12, for the preparation of silane-terminated polyurethanes for adhesives, sealants and coatings for the aeronautical, automotive or construction industries.