The present invention relates to esters of polyols and a mixture of fatty acids, their use as a lubricating base and their manufacturing process.

Currently, the lubricating base market is dominated by mineral oils of petroleum origin. In 2008, European production of lubricants amounted to 4.5 million tonnes per year. These lubricating bases are used in various industries such as motor oil, cutting oil for chainsaw chains, oil for offshore petroleum drilling, hydraulic oil for construction machinery and agricultural machinery, etc.

These mineral oils, once used, are not always recycled and cause environmental pollution due to discharge on the ground, in sewers, in lakes and rivers. In view of the potential impact of these lubricating oils on the environment, the development of ecological and biodegradable lubricating bases is essential, in particular for applications in which the lubricant is likely to escape into the environment.

The use of vegetable and animal oils has been known for several years. These oils have the advantage of being ecological. However, they have a low thermal stability, a low resistance to oxidation compared to mineral oils and its † likely to hydrolyze in the presence of water.

Biodegradable lubricating compositions comprising products derived from palm oil and polyols such as neopentylglycol or trimethylolpropane are described in patent application EPI 533360. However, such compositions are only suitable for temperatures ranging from 15 to 40 ° C.

In this context, it therefore remains necessary to develop esters of polyols whose structure can be derived from ingredients preferably of renewable origins, possessing excellent lubricating properties as well as being harmless to the substance. man and the environment.

Summary of the invention

In the context of the invention, it has been observed that esters of at least one polyol and of a mixture of fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10 fatty acid -C12 exhibit excellent properties for lubricant applications.

The present invention results from the unexpected demonstration, by the inventors, that esters of at least one polyol and of a mixture of fatty acids in which the acids are a mixture of 10-undecylenic acid and of n-heptanoic acid from renewable resources exhibit excellent properties for applications in lubricants.

Thus, the present invention relates to esters of at least one polyol and of a mixture of fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10-C12 fatty acid.

The present invention also relates to the use of esters of at least one polyol and of a mixture of linear fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10-C12 fatty acid such as as defined above as a lubricating base.

The present invention also relates to a lubricating base composition comprising esters of at least one polyol and of a mixture of linear fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10- fatty acid. C12 as defined above.

The present invention also relates to a process for the preparation of esters comprising the esterification of a mixture of linear fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10-C12 fatty acid with at least a polyol, optionally in the presence of a catalyst.

The present invention also relates to esters of at least one polyol and of a mixture of linear fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10-C12 fatty acid obtained by the defined process. above.

Detailed description of the invention

The lubricating base compositions according to the invention synthesized from esters of at least one polyol and a mixture of fatty acids of renewable origin, such as for example erythritol and the mixture of fatty acids in which the acids are † a mixture of n-heptanoic acid and 10-undecylenic acid (eg a mixture of OIeris® C7 e † Cl 1: 1 from Arkema), make it possible to achieve properties in terms of thermal stability, oxidation stability, and a viscosity index, higher than the usual esters don † the alcohol is non-biobased, such as for example trimethylolpropane, as is detailed in the examples below.

Thus, the present invention provides a particular lubricating base composition which offers good thermal stability, better oxidation stability and very good lubricating properties. The term “biodegradable” is used here to denote a compound formed of molecules which can be transformed into smaller molecules and less polluting, for example by microorganisms living in the natural environment, such as bacteria, fungi and algae. The end result of this degradation is usually water, carbon dioxide or methane.

By materials, compounds or ingredients “derived from renewable resources” or “biobased”, we mean renewable natural materials, compounds or ingredients whose stock can be reconstituted over a short period on a human scale. These are in particular raw materials of animal or plant origin. By raw materials of renewable origin or bio-resourced raw materials, is meant materials which include bio-resourced carbon or carbon of renewable origin. In fact, unlike materials made from fossil fuels, materials made from renewable raw materials contain carbon 14 ( , 4VS). The “carbon content of renewable origin” or “bio-resourced carbon content” is determined in application of the standards ASTM D 6866 (ASTM D 6866-06) and ASTM D 7026 (ASTM D 7026-04).

The viscosity of a fluid means the resistance it opposes to the internal sliding of its molecules during its flow. The viscosity is given for a reference temperature. The expressed kinematic viscosity is m / s 2 , is calculated using the following formula: o = h / r, where

h is the dynamic viscosity in Pa.s; and

p is the density of the fluid in kg / m 3

Kinematic viscosity is also expressed in Stockes (St) or in centistokes (cSt).

Kinematic viscosity is measured according to the ISO 3104 standard.

Oxidative stability can be determined via two measurements: oxygen induction time and oxygen induction temperature. The oxygen induction time and the oxygen induction temperature can be measured in a differential scanning calorimeter (DSC - Differential scanning calorimetry) according to ISO 1 1357-6: 2018.

The pour point of a product is the minimum temperature at which the product will still flow. The pour point is measured according to ISO 3016.

The viscosity index (VI) (unitless) indicates the rate of change in the viscosity of an oil over a given temperature range, usually between 40 ° C and † 100 ° C. The viscosity index can be defined as the kinematic viscosity gradient of a material, between 40 and 100 ° C. When the viscosity index is low (less than 100) the fluid shows a relatively large variation in viscosity with temperature. When the viscosity index is high (greater than 150), the fluid exhibits relatively little change in viscosity with temperature. In a variety of applications, a high or very high viscosity index is preferable. The viscosity index es † measured according to the test method described in ASTM D 2270.

Esters

The esters according to the invention are formed from at least one polyol e † of a mixture of fatty acids comprising at least one saturated C5-C12 fatty acid e † at least one unsaturated C10-C12 fatty acid.

According to one embodiment, the esters according to the present invention can be mono-, di-, tri-, e † tetraesters.

The fatty acid mixture according to the invention is preferably derived from renewable resources. The fatty acid mixture according to the invention is preferably of plant or animal origin, linear or branched.

The mixture of fatty acids according to the invention preferably consists mainly of linear fatty acids. Preferably, the mixture of fatty acids according to the invention consists of at least 50% by weight, more preferably from 50% to 70% by weight, still more preferably at least 70% by weight of acids. linear fats relative to the mass of the fatty acid mixture. More preferably, the fatty acid mixture consists of 100% linear fatty acids.

Preferably, linear fatty acids make it possible to increase the viscosity index of the lubricating bases synthesized, to improve their thermal stability and are more easily biodegradable than branched acids, mainly obtained from the petroleum industry.

The fatty acid mixture according to the invention is preferably obtained from castor oil, coconut oil, cottonseed oil, dehydrated castor oil, soybean oil, tall oil, rapeseed oil, sunflower oil, linseed oil, palm oil, tung oil, oiticica oil, oil safflower, olive oil, wood, corn, squash, grape seed, jojoba oil, sesame, walnut, hazelnut, almond, shea, macadamia, alfalfa, rye, peanut, copra, or argan oil.

The term "fatty acid or the mixture of fatty acids" is understood to mean "derived from the oil", a fatty acid present in the oil and / or fatty acids which can be obtained at the end of a transformation. chemical. For example, heptanoic acid and / or 10-undecylenic acid can be obtained from castor oil, typically, by the thermal cracking step of methyl ricinoleate which comes from the transesterification of the oil. castor oil.

Preferably, the saturated C5-C 12 fatty acid according to the invention is selected from the group consisting of pentanoic acid, isovaleric acid, caproic acid, heptanoic acid, n-heptanoic acid. , caprylic acid, pelargonic acid, capric acid, citric acid, tetrahydrofuran 2,5 dicarboxylic acid, tetrahydrofuran 3,5 dicarboxylic acid, azelaic acid, undecanedioic acid, and dodecanedioic acid

Preferably, the C5-C 12 saturated fatty acid according to the invention is n-heptanoic acid, more preferably Oleris® n-heptanoic acid (ARKEMA).

Preferably, the n-heptanoic acid is obtained from castor oil.

Preferably, the unsaturated C10-C12 fatty acid according to the invention is selected from the group consisting of 10-undecylenic acid, and dodec-2 -enedioic acid.

De préférence, l’acide gras insaturé en C10-C12 selon l’invention est l’acide 10-undécylénique, plus préférablement undecylénique Oleris® (ARKEMA).

De préférence, l’acide 10-undécylénique est issu de l’huile de ricin.

Le rapport massique de l’acide gras saturé en C5-C12 sur l’acide gras insaturé en C10-C12 selon l’invention est de 1 :10 à 10:1 , de préférence de 8:2 à 2:8, plus préférablement de 7:3.

Le polyol selon l’invention peut être choisi parmi n’imporfe quel polyol bien connu de l’homme du métier. Le polyol selon l’invention peut être d’origine pétrochimique ou issu de ressources renouvelables.

De préférence, le polyol selon l’invention est un composé organique contenant plusieurs groupes hydroxyles.

Selon un mode de réalisation, les polyols ne ton† pas référence à des composés qui contiennent des groupes fonctionnels autres qu’ hydroxyles.

Le polyol selon l’invention est de préférence sélectionné dans le groupe constitué du frimethylolpropane, du frimethyloléthane, du pentaérythritol, du dipentaérythritol, du tripentaérythritol, du tetra pentaérythritol et du neopenfyl glycol, ou de leurs mélanges.

Le polyol issu de ressources renouvelables selon l’invention est, de préférence, biodégradable. Le polyol issu de ressources renouvelables selon l’invention peut être un polyol de sucre. Typiquement, le polyol de sucre est un composé répondant à la formule chimique générale CnH2n+20n et possédant au moins deux groupes hydroxyles.

Preferably, the sugar polyol is selected from the group consisting of monosaccharides, disaccharides and frisaccharides.

Preferably, the monosaccharide according to the invention is selected from the group consisting of erythritol, xylose, arabinose, ribose, sorbitol, sorbitan, glucose, sorbose, fructose, xylifol and mannitol, more preferably from the group consisting of xylose, arabinose, ribose, glucose, sorbose and fructose.

Preferably, the disaccharide according to the invention is selected from the group consisting of malfose, lactose, and sucrose.

The frisaccharide according to the invention is preferably selected from the group consisting of raffinose, malfotriose, and hydrogenated starch hydrolysates.

More preferably, the sugar polyol according to the invention is erythritol.

The polyol according to the invention is preferably selected from the group consisting of erythritol, xylifol, mannitol, frimethylolpropane, frimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, malfose, lactose , sucrose, raffinose,

maltotriose e † of neopentyl glycol or mixtures thereof, more preferably from the group consisting of erythritol, xylitol, mannitol, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythoprityl, and glycol or their mixtures.

According to one embodiment, the sugar polyol according to the invention is obtained by hydrogenation of a sugar.

Preferably, the mass ratio of the polyol to the mixture of fatty acids is in the range of 1: 4 to 1: 10. More preferably, the weight ratio of polyol to fatty acid mixture is about 1: 5.

Preferably, the ester according to the invention has an oxygen induction time measured in a differential scanning calorimeter at 150 ° C. greater than 2 hours.

Preferably, the ester according to the invention has an oxygen induction temperature measured in a differential scanning calorimeter of greater than 200 ° C.

Preferably, the ester according to the invention has a kinematic viscosity of 14 to 30 mm 2 / s at 40 ° C, and / or less than 6 mm 2 / s at 100 ° C, which is measured according to the ISO 3104 standard. .

Preferably, the ester according to the invention has a pour point of less than -20 ° C.

Process

Preferably, the esterification process according to the invention comprises a step of esterifying at least one polyol according to the invention in the presence of a mixture of excess fatty acids comprising at least one saturated fatty acid Cs-. C12 and at least one C10-C12 unsaturated fatty acid according to the invention, with or without catalyst.

The esterification step according to the invention is preferably carried out at a temperature between 140 ° C and 250 ° C for a period of 0.5 to 12 hours, preferably 1 to 10 hours, more preferably 2 at 8 o'clock.

The esterification step according to the invention is preferably carried out under an inert atmosphere.

The esterification step according to the invention is preferably carried out in a pressure range ranging from 30 mm Hg to 760 mm Hg.

The esterification process according to the invention may include a step of adding an absorbent such as alumina, silica gel, zeolites, activated carbon, and clay.

The process according to the invention can also comprise a step of adding basic water to simultaneously neutralize the residual organic acids and / or hydrolyze the catalyst. In this case, the method according to the invention may include a step of removing the water used by heating and placing under vacuum.

The process according to the invention can also include a step of filtering the solids of the ester mixture containing the major part of the excess acid mixture used in the esterification reaction.

The process according to the invention may include a step of removing excess acids by steam extraction or by any other method of distillation and recycling of the polyol in the reaction vessel. Preferably, the compound obtained by the process according to the invention is purified by distillation at reduced pressure of the unreacted acid. The distillation is preferably carried out under vacuum for 15 to 60 minutes. The distillation is further preferably carried out at a temperature between 140 ° C and 180 ° C. The amount of free acid remaining after the distillation step can be reduced by treatment with epoxy esters, by neutralization with any suitable alkali material such as lime, alkali metal hydroxides, metal carbonates alkaline or basic alumina. When treatment with epoxy esters is carried out, a second distillation under reduced pressure can be carried out to remove excess epoxy ester. When alkaline treatment is performed washing with water can be performed to remove excess unreacted alkaline material.

The process according to the invention may include a step of removing any residual solid material from the ester extracted during a final filtration.

Preferably, the fatty acid mixture according to the invention is present in the reaction to form the ester according to the invention in an excess of about 10 to 50% by moles, preferably about 10 to 30%. in moles, relative to the amount of polyol used.

The process according to the invention can be carried out in the presence of a catalyst. The catalyst can be any catalyst well known to those skilled in the art for esterification reactions. Preferably, the catalyst is selected from the group consisting of tin chloride, sulfuric acid, p-toluene acid

sulfonique, d'acide méthane sulfonique, d'acide sulfosuccinique, d’acide chloridrique, d’acide phosphorique, des catalyseurs à base de zinc, de cuivre, de d'étain, de titane, de zirconium ou de tungstène ; des sels de métaux alcalins tels que l'hydroxyde de sodium ou de potassium, le carbonate de sodium ou de potassium, l'éthoxyde de sodium ou de potassium, le méthoxyde de sodium ou de potassium, les zéolithes et des échangeurs d'ions acides, ou des mélanges de ceux-ci.

Utilisation

Les esters selon l’invention sont, de préférence, utilisés en tant que tels comme base lubrifiante ou huile de base lubrifiante.

The esters according to the invention can also be used as a mixture with other base oils, such as mineral oils, highly refined mineral oils, polyalphaolefins (PAO), polyalkylene glycols (PAG), phosphate esters, silicone oils, diesfers, polyisobufylenes and polyol esters.

In particular, the esters according to the invention are useful for the preparation of a lubricating base composition. The lubricating base composition according to the invention can be used in all types of industries, in particular as automotive lubricants, as metalworking oils, as hydraulic oils, as turbine oils, or even as oils for airplanes.

Preferably, the composition according to the invention can comprise a level of tetraesters greater than or equal to 80% by mass relative to the total amount of ester. More preferably, the composition may contain a level of tetraesters greater than or equal to 93% by mass relative to the total amount of ester.

The composition according to the invention can comprise, in addition to the esters according to the invention, one or more additives. Preferably, the additives are selected from the group consisting of antioxidants, thermal stability improvers, corrosion inhibitors, metal deactivators, lubricant additives, viscosity index improvers, pour point depressants, detergents, dispersants, defoamers, antiwear agents, and additives resistant to extreme pressures.

Preferably, the amount of additives in the composition according to the invention does not exceed 10% by weight, preferably 8% by weight, more preferably 5% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of antioxidants used is between 0.01% and 5% relative to the total weight of the lubricating base composition.

Preferably, the amount of corrosion inhibitors is between 0.01% and 5% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of metal deactivators is between

0.001% and 0.5% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of lubricating additives is between 0.5% and 5% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of agents improving the viscosity index is between 0.01% and 2% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of pour point depressants is between 0.01% and 2% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of detergents is between 0.1% and 5% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of dispersing agents is between 0.1% and 5% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of antifoaming agents is between 0.01% and

2% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of antiwear agents is between 0.01% and 2% by weight relative to the total weight of the lubricating base composition.

Preferably, the amount of additives resistant to extreme pressures is between 0.1% and 2% by weight relative to the total weight of the lubricating base composition.

Antioxidants and thermal stability improvers can be selected from any antioxidant and thermal stability improvers well known to those skilled in the art. By way of example, the antioxidant and the thermal stability improving agent can be selected from the group consisting of:

diphenyl-amine, dinaphthyl-amine, phenylnaphthylamine, in which the phenyl group or the naphthyl group may be substituted, for example by the groups N, N'-diphenyl phenylenediamine, p-octyldiphenylamine, p, p-diocfyldiphenylamine, N-phenyll- naphthyl amine, N-phenyl-2-naphthyl amine, N- (p-dodecyl) phenyl-2-naphthyl amine, di-1-naphthyl amine, e † di-2-naphthyl amine;

phenofhazines, such as N-alkylphenothiazines;

imino (bisbenzyl); and

hindered phenols such as 6- (t-butyl) phenol, 2, ô-di- (t-butyl) phenol, 4-methyl-2, 6- di- (t-butyl) phenol, 4,4'- methylenebis (-2,6-di- (t-butyl) phenol).

Les désactivateurs de métaux peuvent être choisis parmi n’importe quels désactivateurs de métaux bien connus de l’homme du métier. A titre d’exemple, les désactivateurs de métaux peuvent être sélectionnés dans le groupe constitué d’imidazole, de benzamidazole, 2-mercaptobenzthiazole, 2,5-di-mercaptothiadiazole, salicylidine-propylènediamine, pyrazole, benzotriazole, tolutriazole, 2-méthylbenzamidazole, 3,5-diméthyl pyrazole, et méthylène bis-benzotriazole. D’autres exemples de désactivateurs de métaux ou d’inhibiteurs de corrosion comprennent :

- les acides organiques et leurs esters, sels métalliques et anhydrides, tels que N-oléyl-sarcosine, monooléate de sorbitan, naphténate de plomb, acide dodécényl-succinique et ses esters et amides partiels, et acide 4- nonylphénoxyacétique ;

les amines primaires, secondaires et tertiaires alines et cycloaliphatiques et les sels d'amines d'acides organiques et inorganiques, tels que les carboxylates d'alkylammonium solubles dans l'huile ;

- les composés hétérocycliques contenant de l'azote, tels que des thiadiazoles, des imidazolines substituées et des oxazolines ;

les quinoléines, les quinones et les anthraquinones ;

- le gallate de propyle :

le dinonylnaphtalènesulfonate de baryum ;

les dérivés d'esters et d'amides d'anhydrides ou d'acides alcénylsucciniques, les dithiocarbamates, les dithiophosphates ; les sels d'aminés de phosphates d'alkylacides et leurs dérivés.

Les additifs lubrifiants peuvent être choisis parmi n’importe quels additifs lubrifiants bien connus de l’homme du méfier. A titre, d’exemple d’additifs lubrifiants, on peu† citer les dérivés à longue chaîne d'acides gras et d'huiles naturelles, tels que les esters, les amines, les amides, les imidazolines e† les borates.

Les agents améliorant l'indice de viscosité peuvent être choisis parmi n’importe quels agents améliorant l'indice de viscosité bien connus de l’homme du métier. A titre d’exemple d’agents améliorant l'indice de viscosité, on peu† citer les polyméthacrylates, les copolymères de vinylpyrrolidone e† de méthacrylates, les polybutènes e† les copolymères styrène-acrylate.

Les dépresseurs de point d’écoulement peuvent être choisis parmi n’importe quels dépresseurs de point d’écoulement bien connus de l’homme du métier. A titre d’exemple de dépresseurs de point d’écoulement on peu† citer les polyméthacrylates tels que les terpolymères de méthacrylate d'éthylène-acétate de vinyle ; les dérivés de naphtalène alkylés ; e† les produits de condensation de Friedel-Crafts catalysée par de l’urée avec du naphtalène ou des phénols.

The detergent and dispersant agents may be selected from any detergent and dispersant agents well known to those skilled in the art. By way of example of detergent and dispersing agents, mention may be made of polybutenylsuccinic acid amides; polybutenylphosphonic acid derivatives; long chain alkyl substituted aromatic sulfonic acids in their salts; e † metal salts of alkylsulphides, alkylphenols e † condensation products of alkylphenols e † aldehydes.

The anti-foaming agents can be selected from any anti-foaming agents well known to those skilled in the art. As an example of an anti-foaming agent, mention may be made of silicone polymers and certain acrylates.

Antiwear agents and additives resistant to extreme pressure can be selected from any antiwear agents and additives resistant to extreme pressure. As examples of anti-wear agents and additives resistant to extreme pressures, we can mention:

- sulfurized fatty acids and fatty acid esters, such as sulfurized octyl fallafe;

- sulfurized ferpenes;

sulfurized olefins;

- organopolysulphides;

organophosphorus derivatives including amine phosphates, alkyl acid phosphates, dialkyl phosphates, aminedithiophosphates, trialkyl and triaryl phosphorothionates, trialkyl and triaryl phosphines, and dialkyl phosphites such as phosphoric acid monohexyl ester amine salts, dinonylnaphthalenesulfonate amine salts, triphenyl phosphate, trinaphthyl phosphate, diphenylcresyl and phenylphenyl phosphates, naphthyldiphenyl phosphate, triphenylphosphorothionate;

dithiocarbamates, such as antimony dialkyldithiocarbamate; chlorinated and / or fluorinated hydrocarbons and xanthaves.

The invention will be further explained with the aid of the nonlimiting Examples which follow.

Examples

The inventors have studied the properties of an ester according to the present invention for application in lubricants.

1. Preparation of the ester

5 samples are tested:

erythritol ester e † of a mixture of n-hepfanoic acid e † of 10-undecylenic acid (ester according to the invention);

n-hepfanoic acid trimefhylolpropane e † ester (Comparative Example 1);

10-undecylenic acid trimefhylolpropane ester (Comparative Example 2);

trimefhylolpropane ester of unsafe fatty acids (comparative example commercial 3-product PRIOLUBE 2044 ® from CRODA);

pentaerythritol e † ester of linear fatty acids (comparative example 4-commercial product NYCOBASE ® 8410 from NYCO);

pentaerythritol e † ester of branched fatty acids (comparative example 5- commercial product NYCOBASE ® 1060X from NYCO).

Ester according to the invention: Synthesis of an erythritol e † tefraesfer of a mixture of hepfanoiaue and undecyléniaue acids with a molar excess of acid

Erythritol (16.4g, 0.13mol), n-hepfanoic acid (64.3g, 0.49mol) e † 10-undecylenic acid (27.8g, 0.15 mol) with a mass ratio of 70 / 30 are loaded into a 250ml three-necked flask equipped with a stirrer, a thermometer, a condenser and an inlet for nitrogen.

The reaction mixture was heated at 210 ° C. under a nitrogen atmosphere for a period of 5 h, until the theoretical quantity of water was stable. Zirconium tetrabutanolate (1.35 g, 80% in butanol, 1% by weight / total weight of the reactants) is then added in batch to the reactor. The assembly is gradually placed under maximum vacuum at 190 ° C. for 2 hours 30 minutes to distill off the excess acid which has not reacted and leads to 82.8 g of product.

A downstream treatment with activated basic alumina is carried out on the reaction crude and results in an oil with an acid number of 0.02 mgKOH / g.

The kinematic viscosities, the viscosity index (VI.) And the pour point of the product are evaluated and reported in Table 2.

The chemical composition of the product was established by chromatography

gazeuse comme suit : 93.6% de tetraesters, 4.8% d’anhydroesters et 0.1 % de triesters.

Exemple comparatif 1 : Synthèse d’un ester de trimethylolpropane et d’acide n-heptanoïaue avec un excès molaire en acide

Le trimethylolpropane (53.8g, 0.4 mol) et l’acide n-heptanoïque (181 .5g, 1 .38mol) son† chargés dans un tricol de 500ml équipé d’un agitateur, d'un thermomètre, d'un réfrigérant et d'une entrée pour l’azote. Le mélange réactionnel a été chauffé à 185°C sous atmosphère d'azote pendant une durée de 3h, jusqu’à ce que la quantité d'eau théorique soit recueillie. Le tetrabutanolate de zirconium (1 .5g, à 80% dans le butanol, 0,5% massique/masse totale des réactifs) est ensuite ajouté en batch dans le réacteur. Le montage est progressivement mis sous vide maximal à 185°C pendant 3h30 pour distiller l’excès d’acide n’ayan† pas réagi et conduit à 187.4g de produit. Un traitement aval avec de l’alumine basique activée est réalisé sur le brut réactionnel et conduit à une huile avec un indice d’acidité de

0.1 mgKOH/g. La composition chimique du produit a été établie par

chromatographie gazeuse comme suit : 98.8% de triheptanoate de trimethylol propane et 0.03% de diheptanoate de trimethylol propane.

Exemple comparatif 2 : Synthèse d’un ester de trimethylolpropane de l’acide 10-undécyléniaue avec un excès molaire en acide

Le trimethylolpropane (40.4g, 0.30 mol) e† l’acide 10-undécylénique (218g, 1 .1 7mol) son† chargés dans un tricol de 500ml équipé d’un agitateur, d'un thermomètre, d'un réfrigérant et d'une entrée pour l’azote. Le mélange réactionnel a été chauffé à 185°C sous atmosphère d'azote pendant une durée de 3h, jusqu’à ce que la quantité d'eau théorique soit recueillie. Le tetrabutanolate de zirconium (3.2g, à 80% dans le butanol, 1 % massique/masse totale des réactifs) est ensuite ajouté en batch dans le réacteur. Le montage est progressivement mis sous vide maximal à 185°C pendant 3h30 pour distiller l’excès d’acide n’ayan† pas réagi et conduit à 195.3g de produit.

A downstream treatment with activated basic alumina is carried out on the reaction crude and results in an oil with an acid number of 1.8 mgKOH / g. The chemical composition of the product was established by chromatography

gaseous as follows: 98.3% of trimethylol propane triundecylenate and 0.99% of trimethylol propane diundecylenate.

2. Measurement of the resistance to oxidation

Oxidation stability is determined via two measurements: oxygen induction time and oxygen induction temperature. Oxygen induction time and oxygen induction temperature are † measured in a Differential Scanning Calorimeter (DSC).

For the measurement of the oxygen induction time, the sample is heated to 150 ° C. and then maintained at constant temperature. It is then exposed to an oxidizing atmosphere. The time between contact with oxygen and the onset of oxidation is the oxygen induction time.

For the measurement of the oxygen induction temperature, the sample is heated with a constant heating rate under an oxidizing atmosphere until the reaction begins. The oxygen induction temperature is the temperature at which the oxidation reaction begins.

The results are presented in Table 1 below:

[Tables 1]

Table 1: measurement of the resistance to oxidation

The measurements show that the oxygen induction time at 150 ° C of the three samples are similar. The ester according to the invention exhibits a higher oxygen induction temperature than Comparative Examples 1 e † 2. Consequently, the ester according to the invention exhibits better oxidation resistance properties than usual ester synthesized from a non-biobased alcohol.

3. Measurement of kinematic viscosity

The kinematic viscosity was measured at 40 ° C. e † at 100 ° C. according to the ISO 3104 standard. The results, expressed in mm 2 / s, are presented in Table 2 below.

4. Measurement of viscosity index

The viscosity index (unitless) is measured according to the test method described in standard ASTM D 2270. The results are presented in Table 2 below.

5. Pour point measurement

The pour point, expressed in ° C, is measured according to the ISO 3016 standard. The results are presented in Table 2 below.

[Tables 2]

Table 2: Measurement of kinematic viscosity, viscosity index and pour point.

These examples show that the ester according to the invention synthesized from substances of renewable origin exhibits the lowest kinematic viscosities at 40 ° C e † 100 ° C as well as the highest viscosity index, which means that the lubricating base according to the invention has a stable viscosity as a function of the temperature.

The lubricating base of the invention has the lowest pour point, compared to those of the comparative examples synthesized from alcohols obtained from the petroleum industry and unsaturated fatty acids, or linear or branched.

CLAIMS

[Claim 1] Esters of at least one polyol and of a mixture of fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10-C12 fatty acid.

[Claim 2] Esters according to claim 1, in which the mixture consists predominantly of linear fatty acids.

[Claim 3] Esters according to claim 1 or 2, wherein the saturated C5-C12 fatty acid is n-heptanoic acid.

[Claim 4] Esters according to one of claims 1 to 3, wherein the unsaturated C10-C12 fatty acid is 10-undecylenic acid.

[Claim 5] Esters according to any one of claims 1 to 4, wherein the mass ratio of saturated C5-C12 fatty acid to unsaturated C10-C12 fatty acid is from 1: 10 to 10: 1 .

[Claim 6] Esters according to any one of claims 1 to 5, wherein the mass ratio of saturated C5-C12 fatty acid to unsaturated C10-C12 fatty acid is 8: 2 to 2: 8 .

[Claim 7] Esters according to any one of claims 1 to 6, wherein the mass ratio of saturated C5-C12 fatty acid to unsaturated C10-C12 fatty acid is 7: 3.

[Claim 8] Esters according to any one of claims 1 to 7, wherein the weight ratio of polyol to fatty acid mixture is at least 1: 5.

[Claim 9] Esters according to any one of claims 1 to 8, wherein the saturated C5-C12 fatty acid and the unsaturated C10-C12 fatty acid are obtained from renewable resources.

[Claim 10] Esters according to any one of claims 3 to 4, wherein the saturated C5-C12 fatty acid and the unsaturated C10-C12 fatty acid are derived from castor oil.

[Claim 1 1] Esters according to any one of claims 1 to 10, wherein the polyol is selected from the group consisting of sorbitol, erythritol, xylitol, mannitol, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, tripentaerythritol, tetrapentaerythritol, maltose, lactose, sucrose, raffinose, maltotriose, and neopentyl glycol or mixtures thereof.

[Claim 12] Esters according to any one of claims 1-1 1, wherein the polyol is derived from a renewable resource.

[Claim 13] Use of the ester of at least one polyol and of a mixture of fatty acids comprising at least one saturated C5-C12 fatty acid and at least one unsaturated C10-C12 fatty acid as defined in one of claims 1 to 12 as a lubricating base.

[Claim 14] Composition of a lubricating base comprising an ester of at least one polyol and of a mixture of fatty acids comprising at least one C5-C12 saturated fatty acid e † at least one C10- unsaturated fatty acid C12 as defined in one of claims 1 to 12.

[Claim 15] Process for preparing an ester comprising G esterification of a mixture of fatty acids comprising at least one saturated C5-C12 fatty acid e † at least one unsaturated C10-C12 fatty acid with at least one polyol , optionally in the presence of a catalyst.

[Claim 16] Esters of at least one polyol e † of a mixture of fatty acids comprising at least one saturated C5-C12 fatty acid e † at least one unsaturated C10-C12 fatty acid obtained by the process according to claim 15.