Process for the preparation of low-color alkyl polyglycosides involving neutralization of the reaction medium after removal of sugars

Abstract

A process for the preparation of alkyl polyglycosides having a color of 1.5 VCS or less is disclosed, which comprises in succession: 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 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 removing from the reaction medium the reducing sugar of formula (III): HO-(G)-H that has not reacted in step a); c) a step c) of neutralizing the reaction medium from step b) with an aqueous solution comprising a basic agent (Ab); and d) a step d) of recovering at least one composition (C) having a color of 1.5 VCS or less. [Formula 1] JPEG2024538600000005.jpg49170

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 solubilized in the excess of unreacted alcohol.

[0005] APGs are differentiated by the nature 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 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 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 directly 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 observed. For example, the corresponding product is in the form of a solid, in the form of flakes or beads, or in the form of a liquid, depending on the nature of the hydrocarbon alkyl chain R.

[0010] However, the neutralization step with bases (e.g. NaOH, KOH) from the prior art of emulsifiable APGs having a hydrocarbon alkyl chain R with a number of carbon atoms greater than or equal to 12 to achieve a pH value 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. For this reason, a solution is provided to minimize the coloration of compositions containing APGs with a hydrocarbon chain R having a number of carbon atoms greater than or equal to 12. To obtain such low color (<1.5 VCS) compositions based on APGs with a hydrocarbon alkyl chain R having a number of carbon atoms greater than or equal to 12, two levers 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 lever 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] The second lever, commonly used and described in the prior art 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, involves decolorization with hydrogen peroxide (H2O2) during the final step. Although effective, this step is however time-consuming since it requires adjusting the pH value 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. Summary of the Invention [Problem to be solved by the invention]

[0016] Therefore, the technical problem to be solved is 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 any bleaching step. [Means for solving the problem]

[0017] One of the solutions of the present invention is a composition (C) having a color of 1.5 VCS or less, which, for 100% of its weight, comprises: (i) an amount of ≧40% and ≦95% by weight, preferably ≧50% and ≦95% by weight, and even more preferentially ≧70% and ≦90% by weight, of formula (I): an alcohol of formula (I) R-OH (I) (wherein R represents a linear or branched, saturated or unsaturated hydrocarbon group which may contain at least one hydroxyl functional group and may contain from 12 to 22 carbon atoms), or a mixture of alcohols of formula (I); (ii) in an amount of ≧5% by weight and ≦60% by weight, preferably ≧5% by weight and ≦50% by weight, and even more preferentially ≧10% by weight and ≦30% by weight, 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); A method for preparing composition (C), wherein the sum of the weight percentages of the compound and compositions (I) and (II) is understood to be 100% by weight, The above method: a) glycosylation step a), which consists 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 between ≧100° C. and ≦120° C., preferably between ≧100° C. and ≦115° C., and even more preferentially between ≧100° C. and ≦110° C., a) wherein 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) removing from the reaction medium any reducing sugar of formula (III) that has not reacted in step a); c) a base agent (Ab): ·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, ·Formula (IVb): Y(HCO3)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 c) of neutralizing the reaction medium from step b) with an aqueous solution containing a basic agent (Ab) selected from the group consisting of: Step c) in which the neutralization is carried out so as to obtain a reaction medium in which a 5% by weight dispersion of the reaction medium in water has a pH value between 5.5 and 7.5; d) recovering at least one composition (C) having a color of 1.5 VCS or less; The preparation method comprises 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 the DIN-ISO 463 standard. 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] Depending on the case, 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), 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, consisting of a mixture such that composition (C) contains at most 2% by weight, preferably at most 1% by weight, of formula (III): HO-(G)-H (III) containing reducing sugars; It is understood that the sum of the weight percentages of the compounds and compositions (I), (II), and (III) 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; - in step c), the aqueous solution of the basic agent (Ab) comprises between 10% and 25% by weight of said basic agent (Ab); - step c) is carried out in two stages: in a first stage neutralization is carried out with a solution of sodium hydroxide (NaOH) or potassium hydroxide (KOH) so as to obtain a reaction medium having a pH value of between 3.5 and 5.5 for a 5% by weight dispersion in water, and then in a second stage neutralization is carried out with an aqueous solution of a basic agent (Ab) so as to obtain a reaction medium having a pH value of between 5.5 and 7.5 for a 5% by weight dispersion in water; - the reducing sugar of formula (III) selected for glycosylation in step a) is selected from the members of the group consisting of glucose, xylose, arabinose and rhamnose; - step b) of removing the reducing sugar of formula (III) is carried out by filtration, centrifugation or decantation; - step a) comprises the following successive sub-steps: i) introducing an alcohol 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. under mechanical stirring; iii) charging a reducing sugar of formula (III) into a reactor (Re); iv) introducing at least one catalyst (CA) into the reactor (Re); v) heating, under vacuum, the reaction medium present in the reactor (Re) to a temperature 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 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), nonadecyl, arachidyl (or n-eicosyl), behenyl (or n-docosyl), erucyl (13-docosenyl) or 12-hydroxystearyl; 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 substeps ii) and iii), a vacuum step, preferably at a pressure of less than or equal to 50 mbar; - sub-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 method according to the invention consists in carrying out a filtration / centrifugation step before neutralizing the product with an aqueous solution containing a basic agent (Ab).

[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, - less than 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, - less than 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, - less than 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 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, - less than 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; - less than 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, - less than 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, - less than 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, - less than 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, - less than 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 the base agent (Ab) on the color of a composition of fatty alcohol and alkyl polyglucoside when the neutralizing base agent (Ab) used is a carbonate according to the invention or sodium hydroxide (comparative neutralizing agent). After a substep of filtration of the reaction medium, a comparison was made between carbonate and sodium hydroxide as a function of the pH range.

[0044] Table 1 below summarizes the neutralization results, including those of filtered reaction media obtained by glycosylation reactions between crystalline glucose and different fatty alcohols, the C-16 / 18-cetearyl cuts, in cut or pure form, 1-tetradecanol (a C14 alcohol), 1-dodecanol (a C12 alcohol). The different parameters investigated are the nature of the pre-neutralizer (pH value between 3.5 and 5.5 of a 5% by weight dispersion in water of the filtered and neutralized medium, pH value between 5.5 and 7.5 of a 5% by weight dispersion in water of the medium (Na2CO3 and / or NaOH).

[0045] 1. Examples of the Invention Example 1.1 Cut of 16 / 18 alcohol and Na2CO3 as neutralizing agent according to the present invention Step 1: Glycosylation reaction: 529.3 g of cetearyl alcohol (C-16 / 18) are charged into a reactor equipped with a mechanical stirrer and a vacuum distillation apparatus. 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 mbar. 69.5 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification (glycosylation) reaction, 0.5 g of a 50% aqueous solution of hypophosphorous acid (H3PO2) is added, followed by 0.6 g of a 98% aqueous solution of sulfuric acid (H2SO4), and the temperature is increased and maintained at 105°C. The reaction is allowed to continue for 5 hours and 45 minutes.

[0046] Step 2: Filtration and neutralization of the reaction medium: The medium is cooled to 80° C. at atmospheric pressure and then filtered through a bell filter (3-6 μm) fitted with plates to remove residual sugars. 167 g of product thus obtained are reintroduced into the reactor at 85° C. and then neutralized by adding, with stirring, 1.7 g of a 10% aqueous solution of Na2CO3 to obtain a composition called (composition 1).

[0047] analysis: - the pH value of a 5% by weight dispersion in water of (composition 1) is 6.4; - (Composition 1) has a color measurement of 0.9 VCS.

[0048] Example 1.2 16 / 18 alcohol cut and NaOH as pre-neutralizing agent and Na2CO3 as neutralizing agent according to the present invention Step 1: Glycosylation reaction: 529.3 g of cetearyl alcohol (C-16 / 18) are charged into a reactor equipped with a mechanical stirrer and a vacuum distillation apparatus. 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 mbar. 69.5 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification (glycosylation) reaction, 0.5 g of a 50% aqueous solution of H3PO2 and then 0.6 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.

[0049] Step 2: Filtration and neutralization of the reaction medium: The medium is cooled to 80° C. at atmospheric pressure and then filtered through a bag filter (100 μm) to remove residual sugars. 264.4 g of product thus obtained are reintroduced into the reactor at 75° C. and then preneutralized by introducing 0.56 g of a 25% aqueous solution of NaOH, with stirring, to achieve a pH value of 4.1 of a 5% by weight dispersion in water of the medium present in the reactor and a color of 1.6 VCS.

[0050] The product is then neutralized, still with stirring, by introducing, at 75° C., 0.9 g of a 10% aqueous solution of Na2CO3, to obtain a composition called (composition 2).

[0051] analysis: - the pH value of a 5% by weight dispersion in water of (composition 2) is 6.4; - (Composition 2) has a color measurement of 1.0 VCS.

[0052] Example 1.3 1-Tetradecanol (myristyl alcohol) and NaOH as pre-neutralizing agent 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 355.8 g of myristyl alcohol (1-tetradecanol). The myristyl alcohol is melted at 85° C., stirred and sparged with nitrogen. The medium is placed under a vacuum of 25 mbar. 49.7 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification (glycosylation) reaction, 0.38 g of a 50% aqueous solution of H3PO2, then 0.61 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.

[0053] Step 2: Neutralization of the reaction medium: The medium is cooled to 80° C. at atmospheric pressure and then filtered through a K1 filter (4 μm) in order to remove residual sugars. 164 g of product thus obtained are reintroduced into the reactor at 80° C. and then preneutralized by introducing, with stirring, 0.46 g of a 25% aqueous solution of NaOH in order to achieve a pH value of 6.0 of a 5% by weight dispersion in water of the medium present in the reactor.

[0054] Finally, the product is neutralized by introducing, in a reactor at 80° C. and with stirring, 0.29 g of a 10% solution of Na2CO3, to obtain a composition called (composition 3).

[0055] analysis: - the pH value of a 5% by weight dispersion in water of (composition 3) is 6.6; - (Composition 3) has a color measurement of 1.1 VCS.

[0056] Example 1.4 1-Tetradecanol (myristyl alcohol) and Na2CO3 as a 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 355.8 g of myristyl alcohol (1-tetradecanol). The alcohol is melted at 85° C., stirred and sparged with nitrogen. The medium is placed under a vacuum of 25 mbar. 49.7 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification (glycosylation) reaction, 0.38 g of a 50% aqueous solution of H3PO2 and then 0.61 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.

[0057] Step 2: Neutralization of the reaction medium: The medium is cooled to 80° C. at atmospheric pressure and then filtered through a K1 filter (4 μm) to remove residual sugars. 160.5 g of product are then reintroduced into the reactor at 70° C. and then neutralized by adding, with stirring, 1.77 g of a 10% aqueous solution of Na2CO3 to obtain a composition called (composition 4).

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

[0059] Example 1.5 1-Dodecanol (Lauryl Alcohol) and Na2CO3 as Neutralizing Agent According to the Invention Step 1: Glycosylation reaction: A reactor equipped with a mechanical stirrer and a vacuum distillation apparatus is charged with 190.6 g of lauryl alcohol (1-dodecanol). The alcohol is melted at 85°C, stirred and sparged with nitrogen. The medium is placed under vacuum at a pressure of 30 mbar. 26.6 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification (glycosylation) reaction, 0.2 g of a 50% aqueous solution of H3PO2, then 0.3 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.

[0060] Step 2: Neutralization of the reaction medium: The medium is cooled to 70° C. at atmospheric pressure and then filtered through a K1 filter (4 μm) to remove residual sugars. The product (160 g) is then reintroduced into the reactor at 75° C. and then neutralized by introducing, with stirring, 1.77 g of a 10% aqueous solution of Na2CO3 to obtain a composition called (composition 5).

[0061] analysis: - the pH value of a 5% by weight dispersion in water of (composition 5) is 6.9; - (Composition 5) has a color measurement of 1.0 VCS.

[0062] 2. Comparative Example Example 2.1: Comparative Example (16 / 18 alcohol cut and NaOH as pre-neutralizer and NaOH as neutralizer). Step 1: Glycosylation reaction: 529.3 g of cetearyl alcohol (C-16 / 18) are charged into a reactor equipped with a mechanical stirrer and a vacuum distillation apparatus. 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 mbar. 69.5 g of anhydrous glucose in powder form are added. The medium is inerted under nitrogen. To start the etherification (glycosylation) reaction, 0.5 g of a 50% aqueous solution of H3PO2 and then 0.6 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 cooled to 80° C. at atmospheric pressure and then filtered through a bell filter (3-6 μm) fitted with plates to remove residual sugars. 500 g of product are then reintroduced into the reactor at 85° C. and then neutralized by adding, with stirring, 0.81 g of a 40% aqueous solution of NaOH to obtain a composition called (composition 1′).

[0064] analysis: - the pH value of a 5% by weight dispersion in water of (composition 1') is 6.5, - (Composition 1') has a measured color of 2.8 VCS.

[0065] [Table 1]

[0066] These tests show: - Sodium carbonate alone, neutralized to a pH of 5% dispersion in water between 5.5 and 7.5, can achieve the desired level of coloration (1.5 VCS or less in the case of (composition 1)), whereas sodium hydroxide alone, neutralized to a pH of 5% dispersion in water between 5.5 and 7.5, produces coloration in excess of 1.5 VCS, up to a maximum of about 2.8 VCS (composition 1'). - If the pre-neutralization step is carried out with a solution of NaOH or Na2CO3 and the neutralization step is carried out with an aqueous solution of Na2CO3, the color of the resulting product is very low (below 1.5 VCS).

[0067] It has thus been shown that the use of a solution of Na2CO3 on the composition obtained by carrying out the method according to the invention makes it possible to neutralise a 5% dispersion of said composition in water, after filtration of the residual sugar, to a pH range between 5.5 and 7.5, without increasing the colour of the composition to values ​​exceeding 1.5 VCS.

Claims

1. 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 (I) R-OH (I) wherein R represents a linear or branched, saturated or unsaturated hydrocarbon group which may contain at least one hydroxyl functional group and which may contain from 12 to 22 carbon atoms, 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): a composition (C1) represented by 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 represents the average degree of polymerization of said 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 composition (C), wherein the total weight ratio of the compound and compositions (I) and (II) is understood to be 100% by weight, 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): H-O-(G)-H (III) in the presence of at least one acid catalyst (CA) at a temperature of 100°C or higher and 120°C or lower, 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) removing from the reaction medium said reducing sugar of formula (III) that has not reacted in step a); c) neutralizing the reaction medium from step b) with an aqueous solution containing a basic agent (Ab), wherein the basic agent (Ab) is: ・Formula (IVa): XnCO ３ (IVa) wherein X represents a sodium atom or a potassium atom and n is an integer equal to 2, or X represents a calcium atom or a magnesium atom and n is an integer equal to 1. or ・Formula (IVb): Y(HCO ３ )m (IVb) wherein Y represents a sodium or potassium atom and m is an integer equal to 1, or wherein Y represents a calcium or magnesium atom and m is an integer equal to 2, selected from the group consisting of: Step c) wherein said 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 value between 5.5 and 7.5; d) recovering at least one composition (C) having a color of 1.5 VCS or less; The preparation method comprising the steps of:

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 comprises:

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; 3. The method according to claim 1 or 2, characterized in that the sum of the weight proportions of the compounds and compositions (I), (II) and (III) is understood to be equal to 100% by weight.

4. 3. The method according to claim 1, wherein 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.

5. 3. The method according to claim 1, wherein in step c) the aqueous solution of the basic agent (Ab) comprises between 10% and 25% by weight of the basic agent (Ab).

6. 3. The method according to claim 1 or 2, characterized in that step c) is carried out in two stages: in a first stage, neutralization is carried out with a solution of sodium hydroxide (NaOH) or potassium hydroxide (KOH) so as to obtain a reaction medium having a pH value of between 3.5 and 5.5 for a 5% by weight dispersion in water, and then in a second stage, neutralization is carried out with an aqueous solution of a basic agent (Ab) so as to obtain a reaction medium having a pH value of between 5.5 and 7.5 for a 5% by weight dispersion in water.

7. 3. 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.

8. 3. The method according to claim 1 or 2, wherein step b) of removing the reducing sugars of formula (III) is carried out by filtration, centrifugation or decantation.

9. Step a) comprises the following successive sub-steps: i) introducing an alcohol 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 catalyst (CA) into said reactor (Re); v) heating, under vacuum, the reaction medium present in the reactor (Re) to a temperature 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; 3. The method according to claim 1, further comprising:

10. 10. The method according to claim 9, wherein 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), nonadecyl, arachidyl (or n-eicosyl), behenyl (or n-docosyl), erucyl (13-docosenyl), or 12-hydroxystearyl.

11. 10. The method according to claim 9, wherein 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. The method of claim 9, further comprising a vacuum step between substeps ii) and iii) at a pressure of 50 mbar or less.

14. 10. The method of claim 9, wherein substep vi) is carried out at atmospheric pressure.

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