METHOD FOR THE PREPARATION OF A SURFACE COMPOSITION BASED ON A GLYCINBETAINE STER SALT AND COMPOSITION SO LAYERED

Description

SUBJECT OF THE INVENTION

[0001] The present invention relates to a process for preparing a surfactant composition based on glycine betaine ester salt, as well as the composition thus obtained. It also relates to the uses of this composition. It further relates to a product comprising the aforementioned composition. BACKGROUND OF THE INVENTION

[0002] Surfactants are essential raw materials for the manufacture of a variety of products. While cationic surfactants represent a smaller market than anionic or non-ionic surfactants, they are nevertheless of interest in a wide range of applications, particularly in the manufacture of detergents and cosmetics, as well as in water treatment.

[0003] Due to their toxicity, some surfactants such as dimethyldialkylammonium salts, present in most fabric softeners, are seeing their use limited or even abandoned in some European countries such as Germany and the Netherlands. Under pressure from ecology, surfactant producers must offer products that are less polluting, more biodegradable, and have the lowest possible ecotoxicity. In addition to environmental constraints, consumers are also seeking products that are as natural as possible.

[0004] In this context, glycine betaine, an inexpensive natural substance, is a prime raw material for the preparation of surfactants. Derived from sugar beet molasses, obtained after extraction of sucrose, it currently remains a by-product of the sugar industry. Grafting fatty alcohols and amines onto glycine betaine provides access to cationic amphiphilic molecules without the classic step of quaternizing a tertiary amine using generally toxic methylating agents.

[0005] Thus, in US Pat. No. 7,829,521, glycine betaine esters have been proposed, obtained by reacting glycine betaine with at least two equivalents of a sulfonic acid, such as methanesulfonic acid, and an alcohol comprising at least 18 carbon atoms. The cationic surfactants thus obtained are present in a mixture with the residual reagents and this mixture can optionally be enriched in glycine betaine ester by treatment with an organic solvent and / or purified on a silica gel column. It is thus possible to obtain an octadecyl or octadecenyl ester of glycine betaine with a yield of approximately 70% or 85%, respectively. These have a surface tension of approximately 37 mN / m and are more particularly intended for cosmetic application.

[0006] Other similar surfactants, also with a shorter chain (lauric ester), are presented in the publication by F. Goursaud et al in Green Chem., 2008, 10, 310-320. These surfactants are also prepared in the presence of a quantity of methanesulfonic acid of at least two equivalents, relative to the quantity of glycine betaine used, which is described as being necessary to obtain an acceptable yield (of at least 70%). The surface tension of the esters obtained after purification is, again, very high (from 32 to 37 mN / m).

[0007] Glycine betaine lauryl ester is also described, alone or in a mixture with the corresponding myristyl ester, in patent application WO 2013 / 188508. In this document, it is demonstrated (Table 5) that the crude reaction mixture has a lower surface tension than pure glycine betaine ester, making it possible to envisage its use in household detergents. This reaction mixture contains in all cases less than 65% by weight of glycine betaine ester and / or more than 20% by weight of residual sulfonic acid (Table 4). However, it has been demonstrated by the present inventors that adjusting these two parameters makes it possible to further lower the surface tension of these mixtures.

[0008] For its part, document WO 2015 / 078890 discloses a surfactant composition obtained by reacting, in a first step, glycine betaine with an alcohol of formula R1-OH containing 1 to 6 carbon atoms, then with an alcohol of formula R2-OH with a longer chain, in the presence of a sugar hemiacetal. This two-step process results in a complex surfactant composition.

[0009] Furthermore, WO 2015 / 003968 describes deodorant actives consisting of glycine betaine ester salts, which can be prepared according to a process involving the reaction of glycine betaine with an alcohol R-OH where R is a C2-C22 alkyl, in the presence of an excess of acid, at a temperature between 60 and 160°C. Only Examples 1 and 2 concern C8-C22 esters, therefore possibly having surfactant properties. In these examples, the reaction temperature is 140°C and the acid level is less than 1.5 equivalents. The glycine betaine esters are obtained with a yield not exceeding 44%.

[0010] After extensive research, the inventors have thus developed a modified process for the preparation of glycine betaine ester salts in which the esterification reaction is carried out in the presence of a reduced amount of acid and at a higher temperature than the prior art processes described above. This process makes it possible to obtain in a single step surfactant compositions having lower surface tensions and possibly a higher proportion of glycine betaine ester than the surfactant compositions described in the prior art, without significantly affecting the reaction yield. This process can also be carried out in a shorter time and does not require a purification step for the product obtained.

[0011] The synthesis process implemented according to the invention is simple, efficient, environmentally friendly, without solvent or polluting discharge, and easily transposable to the industrial scale to reproducibly obtain a particularly high-performance surfactant composition. SUMMARY OF THE INVENTION

[0012] The subject of the invention is a process for preparing a surfactant composition, comprising the successive steps consisting of: (1) reacting glycine betaine or one of its salts with a linear or branched, saturated or unsaturated fatty alcohol containing from 8 to 24 carbon atoms, in the presence of an organic or inorganic acid; (2) cooling the reaction medium to a temperature of 20 to 90°C; and (3) recovering the surfactant composition thus obtained, characterized in that the organic or inorganic acid represents from 1.5 to 1.9 molar equivalents relative to the number of moles of glycine betaine and in that the reaction is carried out at a temperature of 150 to 180°C.

[0013] It also relates to the surfactant composition obtained using this process, containing the following constituents: (a) from 65 to 85% by weight, preferably from 70 to 80% by weight, of glycine betaine ester salt, (b) from 1 to 20% by weight, for example from 1 to 9% by weight or from 10 to 20% by weight, of fatty alcohol, (c) from 1 to 20% by weight, for example from 5 to 15% by weight of organic or inorganic acid, and (d) from 1 to 20% by weight, for example from 2 to 15% by weight, of glycine betaine salt, relative to the total weight of these four constituents.

[0014] The invention also relates to the use of the aforementioned surfactant composition as a wetting agent, particle dispersant, corrosion inhibitor, solubilizer, antistatic and / or detangling agent and / or for improving the effect and / or persistence of insecticidal substances and / or for improving the disinfectant power and / or persistence of the disinfectant effect of antimicrobial substances.

[0015] It also relates to the use of this composition for the manufacture of plastics or products intended for: for the treatment and / or cleaning of the body, plants or hard surfaces, in particular cosmetic products, vehicle wash products, household products, industrial cleaning products, fibre sizing products and plant protection products; for water treatment; for road surfacing; or for oil extraction.

[0016] It also relates to a product comprising the aforementioned composition and at least one constituent chosen from: (a) anionic surfactants, non-ionic surfactants and their mixtures, (b) antimicrobial agents, (c) insecticides, and their mixtures.

[0017] In addition to its low surface tension, the surfactant composition obtained according to the invention has the advantage of being biodegradable (according to OECD 301 standard), low toxicity for the environment (according to OECD 201 and 202 standards) and for humans. DETAILED DESCRIPTION Process

[0018] The surfactant composition according to the invention can be prepared according to a process for the esterification of glycine betaine, or trimethylglycine. Glycine betaine can be of plant or synthetic origin. It is necessary to protonate it beforehand using an organic or inorganic acid, insofar as it is in zwitterionic form (presence of a carboxylate function). The acid can in particular be chosen from inorganic acids such as hydrochloric acid, sulfuric acid, perhalohydric acids, such as perchloric acid, and mixtures thereof.Alternatively, it may be chosen from organic acids, such as alkyl sulfuric acids, for example decyl or lauryl sulfuric acid; aryl sulfonic acids, such as benzene sulfonic acid, paratoluene sulfonic acid; alkyl sulfonic acids, such as triflic acid, methanesulfonic acid, ethanesulfonic acid, decylsulfonic acid, laurylsulfonic acid, camphorsulfonic acid; sulfosuccinic acid; and mixtures thereof. Lewis acids may also be used. Preferably, it is an alkyl sulfonic acid and in particular methanesulfonic acid, since it is readily biodegradable.

[0019] During esterification, the acid function of the salified betaine is reacted with a fatty alcohol, resulting in a glycine betaine ester in salt form. By "fatty alcohol" is meant a linear or branched (preferably linear), saturated or unsaturated alcohol, comprising from 8 to 24 carbon atoms. Examples of such fatty alcohols may be selected from the group consisting of: caprylic alcohol (C8:0), decyl alcohol (C10:0), undecyl alcohol (C11:0), lauryl alcohol (C12:0), myristyl alcohol (C14:0), cetyl alcohol (C16:0), palmitoleyl alcohol (C16:1), stearyl alcohol (C18:0), oleyl alcohol (C18:1), linoleyl alcohol (C18:2), linolenic alcohol (C18:3), arachidic alcohol (C20:0), arachidonic alcohol (C20:4), behenyl alcohol (C22:0), 2-butyloctanol, 2-hexyldecanol, 2-octyldodecanol, 2-decyltetradecanol and mixtures thereof.Suitable fatty alcohol mixtures may be produced from one or more vegetable oils, including soybean, olive, sunflower, corn, palm, copra, cottonseed, linseed, wheat germ, safflower or rapeseed oil, for example.

[0020] The esterification reaction is generally carried out in the absence of solvent. The water produced during the reaction also contributes to the solubilization of glycine betaine in the reaction mixture.

[0021] For carrying out this reaction, from 0.8 to 2 equivalents, for example from 0.9 to 1.0 equivalents, or alternatively from 1.1 to 1.8 equivalents, preferably in this case from 1.2 to 1.6 equivalents and, better still, from 1.3 to 1.5 equivalents of fatty alcohol may be used. In any case, from 1.5 to 1.9 equivalents, preferably from 1.5 to 1.7 molar equivalents of organic or inorganic acid are used for 1 equivalent of glycine betaine. The esterification is carried out at a temperature of 150 to 180°C. In a preferred embodiment of the invention, the glycine betaine, the fatty alcohol and the organic or inorganic acid are mixed at a temperature of 160 to 180°C, for example 170°C, and then the temperature of the mixture is lowered by 10 to 20°C, to 140-160°C, for example 150°C, before the reaction begins. The reaction can be carried out under atmospheric pressure or preferably under reduced pressure, for example at a pressure of 10 to 600 mbar.The pressure will generally be lower the longer the chain length of the fatty alcohol used. In any case, those skilled in the art will know how to adjust the chosen pressure so as to eliminate the water formed during the reaction and shift the equilibrium towards the formation of the ester. The reaction medium is then cooled to a temperature of 20 to 90°C.

[0022] The surfactant composition thus obtained is then recovered, which contains at least 65% by weight, generally from 65 to 85% by weight, for example from 70 to 80% by weight, of at least one glycine betaine ester salt of formula X n-< [(CH 3 ) 3 N +< -CH 2 -COOR] n where: X is an organic or inorganic anion, R is an alkyl radical corresponding to the fatty alcohol R-OH used in the esterification reaction, and n is 1 or 2.

[0023] The anion X is derived from the acid XH described above and may therefore in particular be a chloride, a sulfate, a perchlorate, an alkyl sulfate ion, in particular decyl sulfate or lauryl sulfate, an arylsulfonate ion, in particular benzene sulfonate, paratoluene sulfonate, an alkylsulfonate ion, in particular triflate, methanesulfonate, ethanesulfonate, decylsulfonate, laurylsulfonate, camphorsulfonate, or a sulfosuccinate ion. It is preferred according to the invention that X is chosen from alkylsulfonates and arylsulfonates, in particular from methanesulfonate, triflate, paratoluenesulfonate and camphorsulfonate ions. It is advantageously the methanesulfonate ion.

[0024] The radical R can for its part be chosen from the groups octyl (C8:0), decyl (C10:0), undecyl (C11:0), lauryl (C12:0), myristyl (C14:0), cetyl (C16:0), palmitoleyl (C16:1), stearyl (C18:0), oleyl (C18:1), linoleyl (C18:2), linolenyl (C18:3), arachidyl (C20:0), arachidonyl (C20:4), behenyl (C22:0), 2-butyloctyl, 2-hexyldecyl, 2-octyldodecyl and 2-decyltetradecyl.

[0025] It is understood that, in the case where several fatty alcohols are used in the esterification reaction, the surfactant composition obtained according to the invention will comprise several glycine betaine ester salts. The expression "a glycine betaine ester salt" must therefore be understood, in the context of this description and unless otherwise indicated, as referring to one or more of these salts.

[0026] More specifically, the surfactant composition obtained according to the invention contains: (a) from 65 to 85% by weight, preferably from 70 to 80% by weight, of glycine betaine ester salt, (b) from 1 to 20% by weight, for example from 1 to 9% by weight or from 10 to 20% by weight, of fatty alcohol, (c) from 1 to 20% by weight, for example from 5 to 15% by weight of organic or inorganic acid, and (d) from 1 to 20% by weight, for example from 2 to 15% by weight, of glycine betaine salt, relative to the total weight of these four constituents.

[0027] Advantageously, these constituents represent in total from 90 to 100%, and preferably from 95 to 100% of the weight of the composition. The remainder of the constituents of the composition may in particular consist of a fatty alcohol ether, of formula ROR where R is as defined previously.

[0028] The surfactant composition obtained according to the invention may in particular comprise the above constituents in the following proportions: in the case where the fatty alcohol is lauryl alcohol: from 70 to 80% by weight of glycine betaine lauryl ester salt, from 0.1 to 15% by weight of lauryl alcohol, from 10 to 15% by weight of organic or inorganic acid and from 1 to 10% by weight of glycine betaine salt; in the case where the fatty alcohol is a mixture of lauric and myristic alcohols: from 65 to 75%, preferably from 70 to 75% by weight of salts of lauric and myristic esters of glycine betaine, from 1 to 20%, for example from 1 to 9% by weight or from 10 to 20% by weight of lauric and myristic alcohols, from 10 to 20%, preferably from 10 to 15% by weight of organic or inorganic acid and from 1 to 15% by weight of glycine betaine salt;in the case where the fatty alcohol is oleyl alcohol: from 70 to 80%, preferably from 70 to 75% by weight of glycine betaine oleyl ester salt, from 1 to 20%, for example from 5 to 10% by weight or from 11 to 20% by weight of oleyl alcohol, from 5 to 15% by weight of organic or inorganic acid and from 1 to 15% by weight of glycine betaine salt.;

[0029] It has been observed that the use of alcohol in default, compared to glycine betaine, in the process according to the invention made it possible to obtain surfactant compositions which, in addition to their lower surface tension, compared with the compositions of the prior art, had better solubility in water. The aqueous surfactant solutions obtained from these surfactant compositions are thus more fluid and more transparent, which is advantageous in the case where the solution is intended to be sprayed or impregnated onto a fibrous support such as wipes. Uses

[0030] The surfactant composition obtained according to the invention has a surface tension value of less than 30 mN / m, or even less than 25 mN / m and generally greater than 20 mN / m, measured according to standard NF EN 14370.

[0031] It is thus possible to envisage its use in a variety of applications as a wetting agent, particle dispersant, corrosion inhibitor, solubilizer, antistatic, detangling agent and / or to improve the effect and / or persistence of insecticidal substances and / or to improve the disinfectant power of antimicrobial substances. It can in particular be used for the manufacture of plastics or various products intended in particular: for the treatment and / or cleaning of the body, plants, textiles or hard surfaces, in particular cosmetic products, such as shampoos, conditioners, liquid soaps, bubble baths and shower gels; for washing vehicles such as cars, trucks, trains, buses or airplanes; for household products such as detergents for windows, wall surfaces, floors or dishes; for textile care products; for industrial cleaning products; for fiber sizing products; for plant protection products; for pigmented products such as paints or varnishes; for water treatment; for road surfacing, for example bituminous emulsions; for oil extraction.

[0032] In the case of water treatment, the composition according to the invention makes it possible to detach the biofilm without destroying the effectiveness of the ion exchange resins, unlike conventional cationic surfactants which also have a significant environmental impact given their lack of biodegradability, or their slower biodegradability. This ability to detach biofilms can also be used in oil extraction processes.

[0033] In cosmetic applications, the composition according to the invention is compatible with conventional anionic surfactants and makes it possible to improve the creaminess of the foam they generate. It also protects iron aerosol devices against corrosion. It has also been demonstrated that the composition according to the invention makes it possible to reduce static electricity in hair and facilitates detangling thereof. The solubilizing power of the composition according to the invention also makes it possible to envisage its use for the solubilization of perfumes or essential oils and its dispersing capacity can make it possible to disperse the pigments present in cosmetic compositions.

[0034] In the manufacture of plastics, the composition according to the invention makes it possible to confer electrostatic properties on the surface of the plastic, without affecting its recycling capabilities given its bio-sourced nature.

[0035] When used in the manufacture of plant protection products, the composition according to the invention makes it possible to improve the persistence of active ingredients and the water resistance of products such as herbicides, pesticides or agents modifying plant growth, which can thus be used in smaller quantities. This composition can thus be added, in a form diluted to 25% in water, at a rate of 0.4% by weight, to a product containing an acidic medium, for example.

[0036] The composition according to the invention can also be used in a process for extracting, storing, warehousing or refining oil to limit corrosion of equipment. In this application, it can be added to the oil at a level of 500 to 1000 ppm, for example.

[0037] The invention also relates to a product, for example chosen from those described above, comprising a composition according to the invention and at least one compound chosen from: anionic surfactants, non-ionic surfactants, antimicrobial agents and mixtures thereof. Examples of anionic surfactants are: ethoxylated fatty alcohol sulfate salts, sulfosuccinates, sarcosinates, alkyl- and dialkylphosphates, fatty acid soaps and mixtures thereof.The nonionic surfactants may, for example, be chosen from: fatty acid and polyol esters such as optionally polyethoxylated fatty acid and glycerol esters, optionally polyethoxylated fatty acid and sorbitan esters, polyoxyethylene fatty acid and sucrose esters, such as sucrose stearate, polyoxyethylene fatty alcohol ethers, sugar fatty alcohol ethers, in particular alkylpolyglucosides (APG), polyether-modified polysiloxanes, and mixtures thereof. The antimicrobial agents may be selected from quaternary ammoniums, aldehydes (such as glutaraldehyde and formaldehyde), ethanol, halogenated derivatives, oxidants, phenolic compounds, parabens, isothiazolones (or isothiazolinones), benzoates, imidazoline, hydantoin, guanidine, organic acids such as lactic acid, and mixtures thereof.The insecticidal substances may be selected from organosphosphorus agents (such as acephate, chlorpyrifos or bromophos), nicotinoids, pyrethroids (such as permethrin, bifenthrin or fenvalerate), monoterpenes (such as p-menthane-3,8-diol), organohalogenated compounds (such as lindane, dicofol or toxaphene), N,N-diethyl-3-methylbenzamide, pyrethrum derivatives (such as Pyrethrin I, Pyrethrin II or Jasmoline I), sulfones, sulfonates, formamidines, benzoylureas, rotenones, alkaloids, quassine, ryanidone, aconitine, geraniol and mixtures thereof.

[0038] This product is advantageously presented in the form of an aqueous solution or aqueous gel. Alternatively, it can be presented in the form of an oil-in-water or water-in-oil emulsion or even a paste. In any case, the aqueous phase contained in this product advantageously has a pH ranging from 1 to 8, in particular from 1 to 5. This product can be packaged in any device suitable for the intended use and in particular in a pump bottle, a tube, a pot, an aerosol device or a wipe.

[0039] It advantageously contains from 0.1 to 25% by weight, for example from 1 to 10% by weight, of surfactant composition according to the invention.

[0040] The product according to the invention may also comprise, in addition to the aforementioned antimicrobial, insecticide and surfactant agents, and depending on the intended application, at least one ingredient chosen from: phytosanitary or cosmetic active ingredients, enzymes, chelating agents, thickeners, fatty substances (oils, waxes and / or pastes), fillers, preservatives, pigments and dyes, antioxidants, optical brighteners, and mixtures thereof. FIGURES

[0041] There Figure 1 illustrates the combability of a lock of hair treated respectively with water, a composition containing a reference surfactant and the same composition containing a mixture of glycine betaine ester salts according to the invention. Figure 2is a diagram illustrating the softness of strands treated using a detangling composition containing a reference surfactant or a mixture of glycine betaine ester salts according to the invention, in comparison with a commercial detangler. EXAMPLES

[0042] The invention will be better understood in light of the following examples, which are given purely for illustrative purposes and are not intended to limit the scope of the invention, defined by the appended claims. Example 1 : Synthesis of a surfactant composition according to the invention

[0043] Glycine betaine (1.0 eq) and a fatty alcohol are introduced into a reactor. The set temperature at the mixture is set at 170°C and the pressure is reduced to a value of 10 to 600 mbar, depending on the alcohol used. Once the pressure and temperature set points are reached, a 70% methanesulfonic acid solution (1.6 eq) is added to the reaction mixture. As soon as the addition is complete, the set temperature is brought back to 150°C and the pressure is maintained at a value of 10 to 600 mbar, depending on the alcohol used. Four hours after the start of the acid introduction, the reaction mixture is allowed to cool to 80°C, then the product is recovered, cooled to room temperature, and the reaction yield is determined by 1< H NMR.

[0044] This process was carried out using different fatty alcohols. These were used either in excess (1.4 equivalents) or in deficiency (0.9 equivalents) compared to glycine betaine.

[0045] Surface tension measurement was performed according to NF EN 14370, using a Krüss tensiometer with a horizontally suspended platinum ring. Before each measurement, the ring was thoroughly cleaned and flame-dried. The sample cup was a conical PTFE container placed in a temperature-controlled chamber at 25°C. The sample was prepared with Milli-Q water and continuously stirred using a magnetic stir bar before each measurement.

[0046] The products obtained had the following mass composition: Excessive alcohol Alcohol in default Constituent R=C12:0 R=C12:0 / C14:0 R=C18:1 R=C12:0 R=C12:0 / C14:0 R=C18:1 Alkyl betaine mesylate 74% 72% 72% 77% 70% 72% Residual fatty alcohol 11% 13% 16% 1% 4% 6% Residual methanesulfonic acid 12% 11% 9% 14% 14% 12% Residual glycine betaine mesylate 3% 4% 3% 8% 12% 10% Yield (1)< 93 % 90% 92% 93% 86% 83% Surface tension at CMC (mN / m) 21 at pH 3 21.8 at pH 3 29 at pH 3 21 at pH 3 21.8 at pH 3 29 at pH 3 Excessive alcohol Constituent R = 2-hexyldecyl R = 2-octyldodecyl Alkyl betaine mesylate 69% 73 % Residual fatty alcohol 17 % 16 % Residual methanesulfonic acid 11 % 10 % Residual glycine betaine mesylate 3 % 1 % Yield 93 % 96% Surface tension at CMC (mN / m) 26.0 mN / m at pH = 3 25.9 mN / m at pH = 3 Excessive alcohol Alcohol in default Constituent R = C10:0 R = C10:0 Alkyl betaine mesylate 71 % 75 % Residual fatty alcohol 14 % 2% Residual methanesulfonic acid 12 % 14 % Residual glycine betaine mesylate 4% 9% Yield 92% 91 % Surface tension at CMC (mN / m) 23.0 mN / m at pH = 3 26.3 mN / m at pH = 3 (1)< Calculated relative to glycine betaine (excess alcohol) or fatty alcohol (lack of alcohol)

[0047] It is observed that the yield of the reaction is always greater than or equal to 75%. Furthermore, for esters containing at least 12 carbon atoms, the surface tension at the CMC of the compositions obtained according to the invention does not depend on the quantity of fatty alcohol used, which makes it possible to use a smaller quantity of alcohol. Insofar as the latter significantly impacts the cost of the process, this is an undeniable economic advantage of the process according to the invention. In addition, since residual fatty alcohol reduces the solubility in water of the surfactant compositions, the use of alcohol in default in the process according to the invention makes it possible to obtain more fluid and transparent aqueous surfactant solutions from these surfactant compositions.

[0048] By comparison, the products described in documents WO 2013 / 188508 and US-7,829,521 and in the publication of Goursaud et al (Green Chem., 2008, 10, 310-320) had the following characteristics: Constituent R=C12:0 R=C 12: 0 / C14:0 R=C18:1 R=C18:0 Goursaud WO'508 WO'508 US'521 Goursaud US'521 Goursaud Yield 95% -- -- 85% 85% 80% 70% Surface tension at CMC (mN / m) 32 27 24 36,6 37 37 37

[0049] These products were obtained, according to these documents, by reacting glycine betaine with 1.0 to 1.5 equivalents of alcohol in the presence of 2 to 3 equivalents of methanesulfonic acid, at a temperature of 120 to 140°C and under a pressure of 30 to 100 mbar, for a reaction time of 6 to 8 hours. The products obtained by Goursaud and in US'521 were further purified.

[0050] It thus appears that the products obtained according to the invention, using a smaller quantity of methanesulfonic acid and a higher temperature, exhibit, completely unexpectedly, improved properties, making it possible to envisage their use in a variety of applications. These products are also obtained with a yield of the same order of magnitude (greater than 80%) as those of the prior art but in a shorter time, which represents an undeniable advantage from an industrial point of view. Example 2 : Detangling test

[0051] A comparative test was carried out to detangle a lock of hair using a fatty alcohol emulsion in water containing either a mixture of C18 to C22 glycine betaine ester salts according to the invention, or behentrimonium chloride (Varisoft ®< BT 85 from EVONIK). Water was also used as a control. To do this, 2 locks of hair were first washed using a lauryl ether sulfate-based solution, rinsed with water, then wrung out and finally rubbed 15 times in the palm of the hand to tangle the hair. 1g of each product was then applied to one of the two wet locks, which was then massaged 8 times along its entire length to distribute the product evenly. After 3 minutes of exposure time, the strands were rinsed with tap water and then wrung out by hand. After placing them on a flat surface, the number of comb strokes required to obtain a strand that could be combed without any constraints was measured.This procedure was repeated three times per product, on three different strands. Only one test was carried out with tap water.

[0052] The results of these tests are illustrated in Figure 1 . As can be seen from this Figure, the glycine betaine ester salts according to the invention offer performances equivalent to the reference surfactant. However, the glycine betaine derivatives have a biodegradability superior to the reference surfactant, are 100% biosourced and their synthesis process is more environmentally friendly.

[0053] A sensory analysis of the softness of the strands thus obtained was then carried out by three panelists, in comparison with a strand treated in the same way as above, but with a commercial detangling product (Elsève ®< Total Repair Rapid Restore). The results of this evaluation are presented on the Figure 2As this Figure shows, the resulting strands are perceived as much softer than those treated with the reference surfactant and even with commercial detangler. Example 3 : Formulations

[0054] Several types of products can be prepared using surfactant compositions according to the invention, based respectively on lauric ester (GBE C12:0), myristic ester (GBE C14:0), palmitic ester (GBE C16:0), stearic ester (GBE C18:0), oleic ester (GBE C18:1), behenyl ester (GBE C22:0), 2-octyldodecyl ester (GBE C20R:0) or mixtures thereof. Household detergent

[0055] Lactic acid 80% 2,00 % GBE C12:0 / C14:0 0,40 % Hydroxyethyl cellulose 0,30 % Chelating 0,20 % Scent 0,20 % Dye 0,01 % Deionized water qsp 100,00 % Concentrated fabric softener

[0056] GBE C20R:0 15,00 % 25% Calcium Chloride 1,50 % Scent 0,70 % Dye 0,02 % Conservative 0,10 % Water sp 100,00 % Toilet product

[0057] Phosphoric acid 85% 5,90 % Hydrochloric acid 37% 13,50 % GBE C12:0 3,00 % Scent 0,20 % Dye 0,01 % Water qsp 100,00 % Shampoo

[0058] GBE C18:1 30,00 % Copra diethanolamide 5,00 % Citric acid qsp pH 5 Conservative qs Water qsp 100,00 % Conditioner

[0059] GBE C16:0 / C18:0 3,00 % Cetyl / stearyl alcohols 5,00 % Sodium citrate qs pH 2.5-3.0 Scent 0,25 % Dye 0,02 % Conservative 0,01 % Water qsp 100,00 % Hair mask

[0060] GBE C18:0 / C22:0 3,00 % Cetyl / stearyl alcohols 5,00 % Olive oil 5,00 % Sodium citrate qs pH 2.5-3.0 Panthenol 0,15 % Scent 0,05 % Dye 0,02 % Conservative 0,01 % Water qsp 100,00 % Phytosanitary adjuvant (emulsifiable concentrate)

[0061] GBE C12:0 6,00 % GBE C18:1 8,00 % Anti-foam agent 0,10 % Rapeseed methyl ester qsp 100,00 %

Claims

1. A process for preparing a surfactant composition, comprising the successive steps consisting in: 1) reacting glycine betaine or a salt thereof with a saturated or unsaturated, linear or branched fatty alcohol containing from 8 to 24 carbon atoms, in the presence of an organic or inorganic acid; 2) cooling the reaction medium to a temperature of from 20 to 90°C; and 3) collecting the surfactant composition thus obtained, characterized in that the organic or inorganic acid represents from 1.5 to 1.9 molar equivalents relative to the number of moles of glycine betaine and in that the reaction is performed at a temperature of from 150 to 180°C.

2. The process as claimed in claim 1, characterized in that the acid is chosen from: inorganic acids such as hydrochloric acid, sulfuric acid, perhydrohalic acids, such as perchloric acid, and mixtures thereof; organic acids, such as alkylsulfuric acids, for example decyl or laurylsulfuric acid, arylsulfonic acids, such as benzenesulfonic acid, para-toluenesulfonic acid, alkylsulfonic acids, such as triflic acid, methanesulfonic acid, ethanesulfonic acid, decylsulfonic acid, laurylsulfonic acid, camphorsulfonic acid, sulfosuccinic acid, and mixtures thereof; preferably, the acid is methanesulfonic acid.

3. The process as claimed in claim 1 or 2, characterized in that the fatty alcohol is chosen from the group consisting of: capryl alcohol (C8:0), decyl alcohol (C10:0), undecyl alcohol (C11:0), lauryl alcohol (C12:0), myristyl alcohol (C14:0), cetyl alcohol (C16:0), palmitoleyl alcohol (C16:1), stearyl alcohol (C18:0), oleyl alcohol (C18:1), linoleyl alcohol (C18:2), linolenyl alcohol (C18:3), arachidyl alcohol (C20:0), arachidonyl alcohol (C20:4), behenyl alcohol (C22:0), 2-butyloctanol, 2-hexyldecanol, 2-octyldodecanol, 2-decyltetradecanol and mixtures thereof.

4. The process as claimed in any one of claims 1 to 3, characterized in that from 0.8 to 2 equivalents, for example from 0.9 to 1.0 equivalent, or as a variant from 1.1 to 1.8 equivalents, preferentially in this case from 1.2 to 1.6 equivalents and better still from 1.3 to 1.5 equivalents of fatty alcohol, per 1 equivalent of glycine betaine, are used.

5. The process as claimed in any one of claims 1 to 4, characterized in that from 1.5 to 1.7 molar equivalents of organic or inorganic acid per 1 equivalent of glycine betaine are used.

6. A surfactant composition obtained according to the process as claimed in any one of claims 1 to 5, characterized in that it contains the following constituents: a) from 65% to 85% by weight, preferably from 70% to 80% by weight, of a glycine betaine ester salt, b) from 1% to 20% by weight, for example from 1% to 9% by weight or from 10% to 20% by weight, of a fatty alcohol, c) from 1% to 20% by weight, for example from 5% to 15% by weight, of an organic or inorganic acid, and d) from 1% to 20% by weight, for example from 2% to 15% by weight, of a glycine betaine salt, relative to the total weight of these four constituents.

7. The composition as claimed in claim 6, characterized in that said constituents represent a total of from 90% to 100% and preferably from 95% to 100% by weight of the composition.

8. The use of the surfactant composition as claimed in any one of claims 6 to 7, as a wetting agent, particle dispersant, corrosion inhibitor, solubilizing agent, antistatic and / or disentangling agent and / or for improving the effect and / or the persistence of insecticidal substances and / or for improving the disinfecting power and / or the persistence of the disinfecting effect of antimicrobial substances.

9. The use of the composition as claimed in any one of claims 6 to 7, for manufacturing plastics or products intended for: • treating and / or cleansing the body, plants or hard surfaces, in particular cosmetic products, products for washing vehicles, household products, industrial cleaning products, fiber sizing products and plant protection products; • treating water; • road surfacing; or • extracting petroleum.

10. A product comprising the composition as claimed in any one of claims 6 to 7 and at least one constituent chosen from: (a) anionic surfactants, nonionic surfactants and mixtures thereof, (b) antimicrobial agents, (c) insecticides, and mixtures thereof.