Process for the preparation of low-color alkyl polyglycosides involving neutralization of the reaction medium prior to removal of sugars - Patents.com

Abstract

A method for preparing alkyl polyglycosides having a color of 1.5 VCS or less is disclosed, comprising successively: a) a glycosylation step a) consisting in a reaction between at least one alcohol of formula (I) and at least one reducing sugar of formula (III): HO-(G)-H (III) in the presence of at least one acid catalyst (CA) at a minimum temperature of 100° C. and a maximum temperature of 120° C.; b) a step b) of neutralizing the reaction medium from step a) with an aqueous solution containing a basic agent (Ab); c) a step c) of removing from the neutralized reaction medium the sugar of formula (III) that did not react in step a); and d) a step d) of recovering at least one composition (C) having a color of 1.5 VCS or less.

Description

[Technical field]

[0001] The present invention relates to a method for preparing low color alkyl polyglycosides (color less than 1.5 VCS) with a carbonate neutralizing agent.

[0002] Alkyl polyglycosides, or APGs, are perhaps the best example of bio-based surfactants currently available on the market. Their molecular structure is characterized by the simultaneous presence of a hydrophilic head derived from a reducing sugar (D-glucose, D-xylose, or D-rhamnose are the reducing sugars that are mainly available on the market on an industrial scale) and a lipophilic hydrocarbon chain of various lengths (see formula I: simplified structure of APGs). [ka] [Background technology]

[0003] Their industrial-scale production methods are relatively simple, using as raw materials: i) crystalline glucose, xylose or rhamnose, obtained respectively from the complete hydrolysis of wheat, corn or potato starch or from the hydrolysis of wood hemicellulose, and ii) fatty alcohols from the petrochemical industry (hydrogenation of the methyl esters obtained in the transesterification of vegetable triglycerides).The Fischer glycosylation reaction then consists in linking these two raw materials together by forming a covalent chemical bond, for example in the reaction (II) between glucose and an alcohol. [ka]

[0004] To carry out this glycosylation reaction, an acid catalyst of inorganic or organic origin is required and an excess of alcohol is purposefully introduced, thus acting as reactant and solvent. At the end of the reaction, the APG is dispersed or dissolved in the excess of unreacted alcohol.

[0005] APGs are differentiated by the nature and length of the hydrocarbon alkyl chain R and by their average degree of polymerization DP, which is greater than 1 but less than or equal to 2.5.

[0006] At the end of the glycosylation reaction stage, a neutralization step is carried out to deactivate the catalyst and stop the reaction.

[0007] Depending on the length of the alkyl chain of the alcohol and the associated use, the alcohol is either removed or retained.

[0008] The neutralization step depends on the length of the hydrocarbon alkyl chain. If the latter has less than 12 carbon atoms, neutralization is carried out with aqueous sodium hydroxide. The excess fatty alcohol present at the end of glycosylation is removed by high vacuum or molecular distillation or by evaporation, generally using falling or short-path thin-film evaporators, and the collected APG concentrate is finally dissolved in water. The commercial product thus obtained is therefore in the form of an aqueous APG solution with a weight concentration between 40% and 80%.

[0009] When the hydrocarbon alkyl chain R has a number of carbon atoms greater than or equal to 12, neutralization is generally carried out with sodium or potassium hydroxide alone or in combination with a reducing agent, such as sodium borohydride (NaBH4) or sodium hypophosphite (NaH2PO2), as described in the European patent published under the number EP 0 077 167, the European patent application published under the number EP 0 338 151 A1, and the European patent application published under the number EP 0 388 857 B1. The mixture of APG and excess fatty alcohol is isolated after neutralization and is solid as such. The weight ratio of APG to fatty alcohol depends on the molar stoichiometry initially adopted with respect to the raw materials and their reactivity. However, a ratio of 5% to 30% by weight of APG and 70% to 95% by weight of fatty alcohol is generally found. The resulting composition can be in solid form, for example in the form of flakes or beads, or in liquid form, depending on the nature of the hydrocarbon alkyl chain R. Summary of the Invention [Problem to be solved by the invention]

[0010] However, the neutralization step with bases (e.g. NaOH, KOH) from the prior art of APGs having a hydrocarbon alkyl chain R with a number of carbon atoms greater than or equal to 12 to achieve a pH of a 5 wt. % dispersion in water of the neutralization medium between 5.5 and 7.5 leads to a noticeable coloration of the product.

[0011] For the purposes of the present invention, "measurement of the pH of a 5% by weight dispersion in water" means an analytical method for measuring the pH of a dispersion of an APG-based composition according to the proviso of NF EN 1262, said measurement being carried out by potentiometric measurements using a combined pH electrode (aqueous medium) and a pH meter.

[0012] This coloration can impair the organoleptic properties of the final product into which the APG-containing composition is incorporated. Therefore, a solution is provided to minimize the coloration of compositions containing APGs having a hydrocarbon alkyl chain R with a carbon number of 12 or more. To obtain such low color (<1.5 VCS) compositions based on APGs having a hydrocarbon alkyl chain R with a carbon number of 12 or more, two solutions known in the prior art are conventionally used.

[0013] For the purposes of the present invention, a "low color composition" means a composition having a Gardner color scale defined by DIN-ISO 4630 of 1.5 VCS or less. The Gardner color scale is measured using a LICO 200 / Dr LANGE (or equivalent) colorimeter, which measures light transmission on any medium. Such a colorimeter is operated with a halogen lamp corresponding to standard illuminant C defined by DIN 5033 and with a 2° standard observer. During the measurement, a reference radiation beam compensates for the variations in the recorded values ​​due to lamp and temperature differences.

[0014] The first solution consists in combining the base used with a reducing agent. Among these reducing agents, sodium borohydride (NaBH4) or sodium hypophosphite (NaH2PO2) can be mentioned. This solution is not entirely problem-free. Although very effective, especially in minimizing the coloration of the treated composition, NaBH4 is a reducing agent that is dangerous to handle and use (corrosive products, release of hydrogen). NaH2PO2 itself is not very effective, even when introduced in high concentrations.

[0015] A second solution, commonly used to minimize the color of compositions based on APG with a hydrocarbon chain R with a number of carbon atoms greater than or equal to 12, and described in the prior art, involves decolorization with hydrogen peroxide (H2O2) during a final step. Although effective, this step is however time-consuming, since it requires adjusting the pH of a 5% by weight dispersion in water to between 7.0 and 7.5, while maintaining the oxidizing power of the medium by adding H2O2. This step, which is difficult to carry out, can last several hours, thus significantly increasing the production time and reducing productivity.

[0016] The technical problem to be solved is therefore to find an alternative to the neutralization of compositions based on APGs having a hydrocarbon alkyl chain R with a number of carbon atoms greater than or equal to 12. This alternative must be effective and easy to implement, while guaranteeing a color of 1.5 VCS or less without implementing a bleaching step. [Means for solving the problem]

[0017] One of the solutions of the present invention is a method for preparing a composition (C) having a color of 1.5 VCS or less, comprising, for 100% of its weight: (i) an amount of greater than or equal to 40% by weight and less than or equal to 95% by weight of a compound of formula (I): an alcohol of formula R-OH (I), where R represents a linear or branched, saturated or unsaturated hydrocarbon radical containing from 12 to 22 carbon atoms, which may contain at least one hydroxyl functional group, or a mixture of alcohols of formula (I); ii) an amount of 5% by weight or more and 60% by weight or less of a compound of formula (II): a composition (C1) represented by RO-(G)xH (II) (wherein residue G represents a residue of a reducing sugar, R represents a group as defined in formula (I) and x, which indicates the average degree of polymerization of residue G, represents a decimal number greater than 1.05 and less than or equal to 2.5) or a mixture of compositions (C1) of formula (II); Including, A process for preparing a composition (C), in which the sum of the proportions by weight of the compounds of formulae (I) and (II) in the composition (C) is understood to be equal to 100% by weight, comprising: The method comprising: a) a glycosylation step a) consisting of a reaction between at least one alcohol of formula (I) and at least one reducing sugar of formula (III): HO-(G)-H (III) in the presence of at least one acid catalyst (CA) at a temperature of ≧100° C. and ≦120° C., wherein the acid catalyst (CA) is selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, hypophosphorous acid, methanesulfonic acid, para-toluenesulfonic acid, trifluoromethanesulfonic acid and acidic ion exchange resins; b) removing the reaction medium from step a) by Carbonate of formula (IVa): XnCO3(IVa) (wherein X represents a sodium or potassium atom and n is an integer equal to 2, or X represents a calcium or magnesium atom and n is an integer equal to 1), or Hydrogen carbonate of formula (IVb): Y(HCO3)m (IVb), where Y represents a sodium or potassium atom and m is an integer equal to 1, or Y represents a calcium or magnesium atom and m is an integer equal to 2. Step b) of neutralizing with an aqueous solution containing a basic agent (Ab) selected from the group consisting of: Step b) in which this neutralization is carried out so as to obtain a reaction medium in which a 5% by weight dispersion of said reaction medium in water has a pH between 5.5 and 7.5 c) removing the saccharide of formula (III) that has not reacted in step a) from the neutralized reaction medium; and d) recovering at least one composition (C) having a color of 1.5 VCS or less; The method includes the steps of: DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The color number characterizing the composition (C) prepared by the method that is the subject of the present invention is the Gardner color number defined by DIN-ISO 463. The Gardner color number is measured using a LICO 200 / Dr LANGE (or equivalent) colorimeter that performs light transmission measurements on any medium. Such a colorimeter is operated with a halogen lamp that corresponds to the standard illuminant C defined by DIN 5033 and with a 2° standard observer. During the measurement, a reference radiation beam compensates for the variations in the recorded values ​​due to lamp and temperature differences.

[0019] The unit expressing the Gardner color scale characterizing the composition (C) prepared by the process that is the subject of the present invention is the VCS.

[0020] Optionally, the method according to the invention may have one or more of the following characteristics: said composition (C1) being of the formulae (II1), (II2), (II3), (II4) and (II5): RO-(G)1-H (II1), RO-(G)2-H (II2), RO-(G)3-H (II3), RO-(G)4-H (II4), RO-(G)5-H (II5), and a5, respectively, in molar proportions a1, a2, a3, a4 and a5, wherein the molar proportions a1, a2, a3, a4 and a5 are: ■ Sum: a1+a2+a3+a4+a5 is equal to 1, and ■ The sum a1+2a2+3a3+4a4+5a5 is equal to x Consists of a mixture of such composition (C) contains a compound of formula (III) in an amount of less than or equal to 2% by weight: HO-(G)-H (III) containing reducing sugars; It is understood that the sum of the weight proportions of compounds of formulae (I), (II) and (III) in composition (C) is equal to 100% by weight; the basic agent (Ab) present in the aqueous solution is sodium carbonate of formula (IVa) in which X represents a sodium atom and n is equal to 2; the method comprises, after step c), an additional step of adjusting the pH of a 5% by weight dispersion of the reaction medium in water by adding an aqueous solution containing a basic agent (Ab) as defined above so as to obtain said pH value between 5.5 and 7.5; - the reducing sugar of formula (III) selected for the glycosylation in step a) is selected from the members of the group consisting of glucose, xylose, arabinose and rhamnose; - step c) of removing the reducing sugar of formula (III) is carried out by filtration, centrifugation or sedimentation or by any other solid / liquid separation technique known to the skilled person; if this step of removing the unreacted reducing sugar of formula (III) utilizes filtration, the filter medium may be a filter paper with a suitable pore size (10 micrometers or more) or a cellulose filter plate, optionally in the presence of at least one filter aid known to the skilled person; - in step b), the aqueous solution of the basic agent (Ab) contains between 10% and 40% by weight of said basic agent (Ab); step a) comprises the following successive sub-steps: i) introducing an alcohol of formula (I) or a mixture of alcohols of formula (I) into a reactor (Re) equipped with a mechanical stirrer and a vacuum device; ii) heating the alcohol of formula (I) to a temperature between 80° C. and 90° C. with mechanical stirring; iii) charging a reducing sugar of formula (III) into a reactor (Re); iv) introducing at least one acid catalyst into the reactor (Re); v) heating the reaction medium from substep iv) present in the reactor (Re) under partial vacuum to a temperature of between 100° C. and −110° C. during the reaction; vi) cooling the medium from substep v) to a temperature between 70° C. and 80° C. Contains; in formula (I) and / or in formula (II), the group R is selected from the following groups: lauryl (or n-dodecyl), myristyl (or n-tetradecyl), n-pentadecyl, cetyl (or n-hexadecyl), n-heptadecyl, stearyl (or n-octadecyl), palmitoleyl (or 9-hexadecenyl), oleyl (or 9-octadecenyl), linoleyl (9,12-octadecadienyl), linolenyl (or 6,9,12-octadecatrienyl), n-nonadecyl, arachidyl (or n-eicosyl), behenyl (or n-docosyl), erucyl (13-docosenyl) or 12-hydroxystearyl; in formula (I) and / or in formula (II), the group R is selected from the following groups: 2-hexyloctyl, 2-hexyldecyl, 2-hexyldodecyl, 2-octyldecyl, 2-octyldodecyl, 2-decyltetradecyl, isostearyl (or 16-methylheptadecyl) or isomyristyl (or 13-methyltridecyl); - during substeps ii) to iv), the reactor (Re) is inerted under nitrogen; - the method comprises between steps ii) and iii) a vacuum step, preferably at a pressure of 50 mbar or less; - step vi) is carried out at atmospheric pressure.

[0021] The use of the carbonate of formula (IVa) or the hydrogen carbonate of formula (IVb) does not contribute to an increase in the color of composition (C) (so the presence of a reducing agent is unnecessary), but neutralizes a 5% by weight dispersion of composition (C) to the desired pH (values ​​between 5.5 and 7.5). The use of a base agent (Ab) makes it possible to avoid a decolorization step involving the use of peroxide agents or the like, since it allows a color of 1.5 VCS or less to be achieved.

[0022] The term "reducing sugar" in the definition of formula (II) and the definition of formula (III) refers to saccharide derivatives that do not have in their structure a glycosidic bond formed between the anomeric carbon and the oxygen of the acetal group, as defined in the reference publication: "Biochemistry", Daniel Voet / Judith G. Voet, page 250, John Wiley & Sons, 1990.

[0023] The oligomeric structure (G)x present in formula (II) may be any isomer relating to either optical isomerism, geometric isomerism or positional isomerism, and it may also represent a mixture of isomers.

[0024] In formula (II) as defined above, the group R is attached to G via the anomeric carbon of the saccharide residue to form an acetal functionality.

[0025] According to a particular aspect of the invention, in the definition of the compounds of formula (II) and formula (III), G represents the residue of a reducing sugar selected from glucose, dextrose, sucrose, fructose, idose, gulose, galactose, maltose, isomaltose, maltotriose, lactose, cellobiose, mannose, ribose, xylose, arabinose, lyxose, allose, altrose, rhamnose, dextran or talose.

[0026] According to one particular aspect of the invention, in the definition of the compound of formula (II), G represents the residue of a reducing sugar chosen from the residues of glucose, xylose, arabinose or rhamnose, and x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.5.

[0027] According to a further particular aspect of the invention, in the definition of the compound of formula (II), G represents the residue of a reducing sugar chosen from the residues of glucose, xylose, arabinose or rhamnose and x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, more particularly greater than or equal to 1.25 and less than or equal to 2.0.

[0028] According to another particular aspect of the invention, the reducing sugar of formula (III) is selected from the members of the group consisting of glucose, dextrose, sucrose, fructose, idose, gulose, galactose, maltose, isomaltose, maltotriose, lactose, cellobiose, mannose, ribose, xylose, arabinose, lyxose, allose, altrose, rhamnose, dextran or talose.

[0029] According to a more particular aspect of the invention, the reducing sugar of formula (III) is chosen from glucose, xylose, arabinose or rhamnose.

[0030] The process according to the invention consists in neutralizing the medium at the end of the glycosylation reaction by adding an aqueous solution containing a basic agent (Ab) in order to achieve a pH of a 5% by weight dispersion of said medium in water between 5.5 and 7.5. The residual reducing sugar of formula (III) is then removed by filtration and, optionally, a fresh aqueous solution of the basic agent (Ab) can be added (final step) if the pH of a 5% by weight dispersion of composition (C) in water is below 5.5.

[0031] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - a mixture (M1) of 45% to 55% by weight of alcohols of formula (I), which comprises, relative to 100% of the weight of said mixture (M1), 50% by weight of alcohols of formula (I) in which R represents an n-hexadecyl group and 50% by weight of alcohols of formula (I) in which R represents an n-octadecyl group, - 45% to 54% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl radical obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-hexadecyl radical and an n-octadecyl radical, - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0032] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - a mixture (M'1) of 45% to 55% by weight of alcohols of formula (I), which contains, relative to 100% of the weight of said mixture (M'1), 70% by weight of alcohols of formula (I) in which R represents an n-hexadecyl group and 30% by weight of alcohols of formula (I) in which R represents an n-octadecyl group, - 45% to 54% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl radical obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-hexadecyl radical and an n-octadecyl radical, - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0033] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: a mixture (M''1) of 75% to 90% by weight of alcohols of formula (I), which comprises, relative to 100% of the weight of said mixture (M''1), 50% by weight of alcohols of formula (I) in which R represents an n-hexadecyl group and 50% by weight of alcohols of formula (I) in which R represents an n-octadecyl group, - 10% to 24% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl radical obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-hexadecyl radical and an n-octadecyl radical, - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0034] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - a mixture (M'''1) of 75% to 90% by weight of alcohols of formula (I), which comprises, relative to 100% of the weight of said mixture (M'''1), 70% by weight of alcohols of formula (I) in which R represents an n-hexadecyl group and 30% by weight of alcohols of formula (I) in which R represents an n-octadecyl group, - 10% to 24% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl group obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-hexadecyl group and an n-octadecyl group, - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0035] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - 75% to 90% by weight of an alcohol of formula (I) in which R represents an n-tetradecyl group, - 10% to 24% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl group obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-tetradecyl group; - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0036] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - from 75% to 90% by weight of a mixture of alcohols of formula (I) in which R represents the n-dodecyl, n-tetradecyl, n-hexadecyl and n-octadecyl radicals, - 10% to 24% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl group obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-dodecyl group, an n-tetradecyl group, an n-hexadecyl group, or an n-octadecyl group, - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0037] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - from 75% to 90% by weight of a mixture of alcohols of formula (I) in which R represents an n-eicosyl and n-docosyl radical, - 10% to 24% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl radical obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-eicosyl or n-docosyl radical, - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0038] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - 75% to 90% by weight of a mixture of alcohols of formula (I) in which R represents the n-dodecyl, n-tetradecyl, n-hexadecyl, n-eicosyl and n-docosyl radicals, - 10% to 24% by weight of at least one composition (C1) represented by formula (II) in which G represents a glucosyl or α,β-D-glucopyranosyl radical obtained by removal of the hemiacetal hydroxyl group of α,β-D-glucopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents an n-dodecyl radical, an n-tetradecyl radical, an n-hexadecyl radical, an n-eicosyl radical, or an n-docosyl radical, - 0% to 1% by weight of glucose, The present invention relates to the preparation of a composition (C) comprising:

[0039] According to a particular embodiment, one of the subjects of the above method is a composition (C) having a color of less than or equal to 1.5 VCS and comprising, for 100% of its weight: - from 70% to 90% by weight of a mixture of alcohols of formula (I) in which R represents the n-dodecyl, n-tetradecyl, n-hexadecyl, n-eicosyl and n-docosyl radicals, - 10% to 29% by weight of a composition (C1) represented by formula (II), in which G represents a xylosyl group or an α,β-D-xylopyranosyl group obtained by removal of the hemiacetal hydroxyl group of α,β-D-xylopyranose, x represents a decimal number greater than or equal to 1.05 and less than or equal to 2.0, and R represents a 2-octyldodecyl group, - 0% to 1% by weight of xylose, The present invention relates to the preparation of a composition (C) comprising:

[0040] According to one particular embodiment, the basic agent (Ab) present in the aqueous solution is potassium carbonate of formula (IVa) in which X represents a potassium atom and n is equal to 2.

[0041] According to one particular embodiment, the basic agent (Ab) present in the aqueous solution is sodium hydrogen carbonate of formula (IVb) in which Y represents a sodium atom and m is equal to 1.

[0042] According to one particular embodiment, the acid catalyst (CA) is selected from the members of the group consisting of sulfuric acid, phosphoric acid, hypophosphorous acid, methanesulfonic acid and p-toluenesulfonic acid. EXAMPLES

[0043] A. Comparison of the effect of neutralizing agents on the color of compositions of fatty alcohols and alkyl polyglucosides when the neutralizing base agent used is a carbonate according to the invention or sodium hydroxide (comparative neutralizing agent).

[0044] A comparison was made between carbonate and sodium hydroxide as neutralizing agents. For this purpose, glycosylation reactions were performed starting with crystalline glucose and different fatty alcohols in either cut or pure form: C16 / 18 cetearyl cut, C20 / 22 arachidyl / behenyl cut, 1-dodecanol (C12 alcohol).

[0045] Table 1 below summarizes the neutralization results involving sodium carbonate Na2CO3 (neutralizing agent of the method according to the invention) on the one hand, and sodium hydroxide NaOH (neutralizing agent of the comparative method) on the other hand.

[0046] 1. Examples of the Invention Example 1.1 (16 / 18 alcohol cut and Na2CO3 as neutralizing agent according to the present invention) Step 1: Glycosylation reaction: A reactor equipped with a mechanical stirrer and a vacuum distillation apparatus is charged with 967.4 g of cetearyl alcohol (C16 / 18). The alcohol is melted at 85° C., stirred and sparged with nitrogen. The medium is placed under vacuum at a pressure of less than 50 torr. A quantity of anhydrous glucose in powder form is added so that the molar ratio of fatty alcohol to glucose is 6 / 1. The medium is inerted under nitrogen. To start the etherification reaction, 0.9 g of a 50% aqueous solution of H3PO2 is added, followed by 1.1 g of a 98% aqueous solution of H2SO4, and the temperature is increased and maintained at 105° C. The reaction is allowed to continue for a period of 5 hours and 45 minutes.

[0047] Step 2: Neutralization of the reaction medium: The medium is then cooled to 80° C. at atmospheric pressure and then neutralized by introducing 4.61 g of a 25% aqueous solution of Na2CO3. The product is then introduced into a glass vial and placed in an oven at 80° C. for 24 hours to allow the residual glucose to precipitate. The product (upper phase) is recovered and called (composition 1).

[0048] analysis: the pH of a 5% by weight dispersion of Composition 1 in water is 5.5; -Composition 1 has a color measurement of 0.7 VCS.

[0049] Example 1.2 (Na2CO3 as cut and neutralizer for 20 / 22 alcohol) Step 1: Glycosylation reaction: A mixture of 240.5 g of arachidyl alcohol (C20 alcohol) and behenyl / arachidyl alcohol (C220 / 22 alcohol) in a 70 / 30 weight ratio of C20 and C22 alcohols is charged into a reactor equipped with a mechanical stirrer and a vacuum distillation apparatus. The alcohol mixture is melted at 85°C, stirred and sparged with nitrogen. The medium is placed under vacuum at a pressure of less than 50 torr. 24.6 g of anhydrous glucose dextrose in powder form are added. The medium is inerted under nitrogen. To start the etherification reaction, 0.2 g of a 50% aqueous solution of H3PO2 and then 0.4 g of a 98% aqueous solution of H2SO4 are added, the temperature is increased and maintained at 105°C. The reaction is allowed to continue for 4 hours and 30 minutes.

[0050] Step 2: Neutralization of the reaction medium: The medium is then cooled to 80° C. at atmospheric pressure and then neutralized by introducing 3.3 g of a 10% aqueous solution of Na2CO3. The product has a pH of 5.6 and a color of 0.3 VCS. The product is then introduced into a glass vial and placed in an oven at 80° C. for 24 hours to allow the residual glucose dextrose to settle. The product (upper phase) has a pH of 4.8 and a color of 0.3 VCS. To obtain the final product (composition 2), a final step is carried out at 80° C. by introducing 0.19 g of a 10% aqueous solution of Na2CO3.

[0051] analysis: the pH of a 5% by weight dispersion of composition 2 in water is 7.0; - Composition 2 has a color measurement of 0.6 VCS.

[0052] Example 1.3 (C12 alcohol and Na2CO3 as neutralizing agent) The procedure of Example 1.1 is reproduced by replacing 967.4 g of cetearyl alcohol with 414.5 grams of 1-dodecanol, using anhydrous glucose in powder form in such an amount that the molar ratio of 1-dodecanol to glucose is 6 / 1.

[0053] A product designated (Composition 3) is thus obtained.

[0054] Step 1: Glycosylation reaction: 131.3 g of 1-dodecanol (C12 alcohol) are charged into a reactor equipped with a mechanical stirrer and a vacuum distillation apparatus. The alcohol is placed at 85° C., stirred and sparged with nitrogen. The medium is placed under a vacuum of 30 torr. 18.3 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification reaction, 0.14 g of a 50% aqueous solution of H3PO2, then 0.23 g of a 98% aqueous solution of H2SO4 are added, and the temperature is increased and maintained at 105° C. The reaction is allowed to continue for 5 hours.

[0055] Step 2: Neutralization of the reaction medium: The medium is then cooled to 67° C. at atmospheric pressure and then neutralized by introducing, with stirring, 0.29 g of a 25% aqueous solution of Na2CO3. The product is filtered through filter paper (approximately 10 μm) to remove residual glucose and obtain a product called (Composition 3).

[0056] analysis: the pH of a 5% by weight dispersion of composition 3 in water is 6.1; - Composition 3 has a color measurement of 1.5 VCS.

[0057] Example 1.4 (16 / 18 alcohol cut and Na2CO3 as neutralizing agent) The procedure of Example 1.1 is reproduced, substituting 4.61 grams of a 25% aqueous solution of Na2CO3 for the appropriate weight of said 25% solution of Na2CO3, so as to obtain a pH of 7.4 for the 5% dispersion of the final composition thus obtained (Composition 4).

[0058] analysis: the pH of a 5% by weight dispersion of composition 4 in water is 7.4; - Composition 4 has a color measurement of 1.0 VCS.

[0059] Example 1.5 (16 / 18 alcohol cut and Na2CO3 as neutralizing agent) The procedure of Example 1.1 is reproduced, substituting 4.61 grams of a 25% aqueous solution of Na2CO3 for the appropriate weight of said 25% solution of Na2CO3, so as to obtain a pH of 8.2 for the 5% dispersion of the final composition thus obtained (Composition 5).

[0060] A product designated (Composition 5) is thus obtained.

[0061] analysis: the pH of a 5% by weight dispersion of composition 5 in water is 8.2; - Composition 5 has a color measurement of 2.3 VCS.

[0062] 2-Comparative Example Example 2.1 (16 / 18 alcohol cut and NaOH as neutralizer) Step 1: Glycosylation reaction: A reactor equipped with a mechanical stirrer and a vacuum distillation apparatus is charged with 240.9 g of cetearyl alcohol (C-16 / 18). The alcohol is melted at 85°C, stirred and sparged with nitrogen. The medium is placed under vacuum at a pressure of less than 50 torr. 31.6 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification reaction, 0.22 g of a 50% aqueous solution of H3PO2, then 0.28 g of a 98% aqueous solution of H2SO4 are added, the temperature is increased and maintained at 105°C. The reaction is allowed to continue for 5 hours and 45 minutes.

[0063] Step 2: Neutralization of the reaction medium: The medium is then cooled to 72° C. at atmospheric pressure and then neutralized by introducing, with stirring, 0.73 g of a 25% aqueous solution of NaOH. The product is then introduced into a glass vial and placed in an oven at 80° C. for 24 hours to allow the residual glucose to precipitate. The product (upper phase) is recovered (comparative composition 1).

[0064] analysis: the pH of a 5% by weight dispersion of Comparative Composition 1 in water is 6.1; - Comparative Composition 1 has a color measurement of 4.1 VCS.

[0065] Example 2.2 (20 / 22 Alcohol Cut and NaOH as Neutralizer) The procedure of Example 2.1 is reproduced using 240.9 g of cetearyl alcohol replaced by 59.9 grams of a mixture of arachidyl alcohol (C20) and behenyl alcohol (C22) in a weight ratio of 70 / 30 (C20 alcohol / C22 alcohol), and anhydrous glucose in powder form in such an amount that the molar ratio of fatty alcohol to glucose is 6 / 1.

[0066] A product, designated (Comparative Composition 2), is thus obtained.

[0067] analysis: the pH of a 5% by weight dispersion of Comparative Composition 2 in water is 5.7; - Comparative composition 2 has a color measurement of 6.3 VCS.

[0068] Example 2.3 (C12 Alcohol and NaOH as Neutralizing Agent) Step 1: Glycosylation reaction: 131.3 g of 1-dodecanol (C12) are charged into a reactor equipped with a mechanical stirrer and a vacuum distillation apparatus. 1-dodecanol is introduced at 85° C., stirred and sparged with nitrogen. The medium is placed under a vacuum of 30 torr. 18.3 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification reaction, 0.14 g of a 50% aqueous solution of H3PO2 and then 0.23 g of a 98% aqueous solution of H2SO4 are added, the temperature is increased and maintained at 105° C. The reaction is allowed to continue for 5 hours.

[0069] Step 2: Neutralization of the reaction medium: The medium is then cooled to 67° C. at atmospheric pressure and then neutralized by introducing, with stirring, 0.29 g of a 25% aqueous solution of NaOH. The product is filtered through filter paper (approximately 10 μm) to remove residual glucose and obtain a final product called (Comparative Composition 3).

[0070] analysis: the pH of a 5% by weight dispersion of Comparative Composition 3 in water is 6.0; Comparative composition 3 has a color measurement of 1.8 VCS.

[0071] [Table 1]

[0072] Analysis and Observations Regardless of the fatty chain length tested (C12 to C22), the use of a solution of NaOH as a base agent to neutralize the reaction medium to achieve a pH value of 5.5 or more for a 5% by weight dispersion of the reaction medium in water strongly colors the composition comprising the residual fatty alcohols and the alkyl polyglucosides formed. In fact, after filtration of the residual sugars, the colors measured in these tests vary between 1.8 and 6.3 VCS. By comparison, when a neutralization step is carried out using a solution of Na2CO3 to achieve a pH value of 5.5 or more for a 5% by weight dispersion of the reaction medium in water, the color of the composition comprising the residual fatty alcohols and the alkyl polyglucosides formed has a value of 1.5 VCS or less.

[0073] B - Effect of the pH of a 5% by weight dispersion in water of a composition of fatty alcohol and alkyl polyglucoside on the color of the final product when the neutralization step is carried out with carbonate. By carrying out the general method presented above, three experiments were carried out. These three tests (Example 1.1, Example 1.4 and Example 1.5) describe the preparation of compositions containing cetearyl alcohol and alkylpolyglucosides with linear C16 and C18 chains, said compositions (Composition 1, Composition 4 and Composition 5) prepared by carrying out the method according to the invention and characterized by different pH values ​​of a 5% by weight dispersion of each composition (see Table 2).

[0074] [Table 2]

[0075] Observations and Analysis The results obtained show that the method according to the invention allows the achievement of color values ​​of up to 1.5 VCS when the pH of a 5% by weight dispersion of the prepared composition is between 5.5 and 7.5. In contrast, when the pH of a 5% by weight dispersion of the prepared composition is 8.2, the color of the obtained composition is higher than the maximum desired color of 1.5 VCS.

Claims

1. A method for preparing a composition (C) having a color of 1.5 VCS or less, comprising, for 100% of its weight: i) an amount of at least 40% by weight and at most 95% by weight of a compound of formula (I): an alcohol of formula R-OH (I) in which R represents a linear or branched, saturated or unsaturated hydrocarbon group containing from 12 to 22 carbon atoms, which may contain at least one hydroxyl functional group, or a mixture of alcohols of formula (I); ii) an amount of at least 5% by weight and at most 60% by weight of a compound of formula (II): R-O-(G)x-H (II) (wherein residue G represents a residue of a reducing sugar, R represents a group as defined in formula (I), and x, which indicates the average degree of polymerization of residue G, represents a decimal number greater than 1.05 and less than or equal to 2.5), or a mixture of compositions (C1) of formula (II); A method for preparing a composition (C), in which the sum of the weight proportions of the compounds of formulae (I) and (II) in the composition (C) is understood to be equal to 100% by weight; The method comprising: a) glycosylation step a), which comprises the reaction between at least one alcohol of formula (I) and at least one reducing sugar of formula (III): H-O-(G)-H (III) in the presence of at least one acid catalyst (CA) at a temperature of ≧100° C. and ≦120° C., wherein said at least one acid catalyst (CA) is selected from the group consisting of sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid, hypophosphorous acid, methanesulfonic acid, para-toluenesulfonic acid, trifluoromethanesulfonic acid and acidic ion exchange resins; b) reacting the reaction medium from step a) with Carbonate of formula (IVa): XnCO ３ (IVa) wherein X represents a sodium or potassium atom and n is an integer equal to 2, or X represents a calcium or magnesium atom and n is an integer equal to 1; or ■ Hydrogen carbonate of formula (IVb): Y(HCO ３ )m (IVb) wherein Y represents a sodium or potassium atom and m is an integer equal to 1, or Y represents a calcium or magnesium atom and m is an integer equal to 2. Step b) of neutralizing with an aqueous solution comprising a basic agent (Ab) selected from the group consisting of: Step b), wherein said neutralization is carried out so as to obtain a reaction medium whose 5% by weight dispersion in water has a pH between 5.5 and 7.5; c) removing the sugar of formula (III) that has not reacted in step a) from the neutralized reaction medium; and d) recovering at least one composition (C) having a color of 1.5 VCS or less. A method including the following in succession.

2. The composition (C1) is represented by the formulas (II1), (II2), (II3), (II4), and (II5): RO-(G)1-H (II1), RO-(G)2-H (II2), RO-(G)3-H (II3), RO-(G)4-H (II4), RO-(G)5-H (II5), The molar ratios a1, a2, a3, a4, and a5 of the compounds represented by the formula: Sum: a1+a2+a3+a4+a5 is equal to 1, - The sum a1 + 2a2 + 3a3 + 4a4 + 5a5 is equal to x, 2. The method of claim 1, wherein the mixture is:

3. The composition (C) contains a compound of formula (III) in an amount of 2% by weight or less: H-O-(G)-H (III) containing reducing sugars; 2. The method according to claim 1, characterized in that the sum of the weight proportions of the compounds of formulae (I), (II) and (III) in composition (C) is understood to be equal to 100% by weight.

4. 2. The method according to claim 1, characterized in that the basic agent (Ab) present in the aqueous solution is sodium carbonate of formula (IVa) in which X is a sodium atom and n is equal to 2.

5. 2. The method according to claim 1, characterized in that it comprises, after step c), an additional step of adjusting the pH of a 5% by weight dispersion of said reaction medium in water by adding an aqueous solution comprising said basic agent (Ab) as defined above, so as to obtain said pH value between 5.5 and 7.

5.

6. 2. The method of claim 1, wherein the reducing sugar of formula (III) selected for glycosylation in step a) is selected from the group consisting of glucose, xylose, arabinose and rhamnose.

7. 2. The method of claim 1, wherein step c) of removing the reducing sugars of formula (III) is carried out by filtration, centrifugation, or sedimentation.

8. 2. The method according to claim 1, characterized in that in step b), the aqueous solution of basic agent (Ab) contains between 10% and 40% by weight of the basic agent (Ab).

9. Step a) comprises the following successive sub-steps: i) introducing an alcohol of formula (I) or a mixture of alcohols of formula (I) into a reactor (Re) equipped with a mechanical stirrer and a vacuum; ii) heating said alcohol of formula (I) to a temperature between 80°C and 90°C under mechanical stirring; iii) charging said reducing sugar of formula (III) into said reactor (Re); iv) introducing at least one acid catalyst into said reactor (Re); v) heating, during the reaction, the reaction medium from substep iv) present in the reactor (Re) to a temperature between 100°C and 110°C under partial vacuum; vi) cooling the medium from substep v) to a temperature between 70°C and 80°C; 2. The method of claim 1, comprising:

10. 10. The method according to any one of claims 1 to 9, characterized in that in formula (I) and / or formula (II), the group R is selected from the following groups: lauryl (or n-dodecyl), myristyl (or n-tetradecyl), n-pentadecyl, cetyl (or n-hexadecyl), n-heptadecyl, stearyl (or n-octadecyl), palmitoleyl (or 9-hexadecenyl), oleyl (or 9-octadecenyl), linoleyl (9,12-octadecadienyl), linolenyl (or 6,9,12-octadecatrienyl), n-nonadecyl, arachidyl (or n-eicosyl), behenyl (or n-docosyl), erucyl (13-docosenyl) or 12-hydroxystearyl.

11. 10. The process according to any one of claims 1 to 9, characterized in that in formula (I) and / or formula (II), the group R is selected from the following groups: 2-hexyloctyl, 2-hexyldecyl, 2-hexyldodecyl, 2-octyldecyl, 2-octyldodecyl, 2-decyltetradecyl, isostearyl (or 16-methylheptadecyl) or isomyristyl (or 13-methyltridecyl).

12. 10. The method according to claim 9, characterized in that during substeps ii) to iv), the reactor (Re) is inerted under nitrogen.

13. 10. A method according to claim 9, characterized in that it comprises a vacuum sub-step between sub-steps ii) to iii), preferably at a pressure of 50 mbar or less.

14. 10. The method according to claim 9, characterized in that step vi) is carried out at atmospheric pressure.