PROCESS FOR PREPARING COMPOSITIONS COMPRISING ALKYL(ALKYL-GLUCOSIDE)URONATES, SAID COMPOSITIONS AND USE THEREOF AS A SURFACTANT

Abstract

The present invention relates to a novel process for preparing compositions comprising alkyl(alkyl-glucoside)uronates, from biobased or biocompatible/biodegradable raw materials, and also salts and acids thereof.

Claims

1) A process for preparing a composition comprising: (i) alkyl(alkyl guloside)uronates of formulae (Ia), (Ib) and (Ic): ##STR00005## or (ii) a mixture of alkyl(alkyl guloside)uronates of formulae (Ia), (Ib) and (Ic) and of alkyl(alkyl mannoside)uronates of formulae (Ila), (IIb) and (IIc): ##STR00006## wherein R.sub.1 is a linear or branched, saturated or unsaturated alkyl chain having from 2 to 22 carbon atoms; R.sub.2 is a hydrogen atom, R.sub.1 is an alkali metal atom, an alkaline-earth metal atom, or a quaternary ammonium group of formula (III): ##STR00007## wherein each of R.sub.3 to R.sub.6 is independently a hydrogen atom, an alkyl having from 1 to 6 carbon atoms or a hydroxyalkyl having from 1 to 6 carbon atoms, and characterized in that said process comprises: a) a step of hydrolysis of poly(oligo)guluronates, of oligoalginates, of alginates and/or brown algae; b) a step of esterification and glycosylation of the hydrolysate resulting from step a) with a linear or branched, saturated or unsaturated alcohol of formula ROH, having from 1 to 4 carbon atoms; c) a step of trans-esterification and trans-glycosylation of the reaction medium resulting from step b) with a linear or branched, saturated or unsaturated alcohol of formula ROH having from 2 to 22 carbon atoms; d) optionally a step of neutralization of the reaction medium resulting from step c) in the presence of water and of a base M(OH).sub.x in which M is an alkali metal or alkaline-earth metal, and x is the valency.

2) The process as claimed in claim 1, wherein step a) is carried out in the presence (i) of water and/or of an ionic solvent and/or of a eutectic solvent, and (ii) of an acid catalyst.

3) The process as claimed in claim 2, wherein the acid catalyst is chosen from the group consisting of: hydrochloric acid, sulfuric acid, an alkyl sulfuric acid, a sulfonic acid, an alkylsulfonic acid or an alkyl sulfosuccinate, perhalohydric acids, metals, oxides thereof or salts thereof such as halides thereof.

4) The process as claimed in claim 3, wherein the acid catalyst is methanesulfonic acid.

5) The process as claimed in any one of claims 1 to 4, wherein the alcohol ROH is n-butanol.

6) The process as claimed in any one of claims 1 to 5, wherein the alcohol ROH is chosen from the group consisting of dodecanol and oleyl alcohol.

7) The process as claimed in any one of claims 1 to 6, wherein the esterification and glycosylation step b) is carried out at atmospheric pressure and at the boiling point of water or of the azeotrope formed with the alcohol ROH.

8) The process as claimed in any one of claims 1 to 7, wherein the trans-esterification and trans-glycosylation step c) is carried out at 70 C. under reduced pressure in order to recycle the alcohol ROH.

9) A process for preparing a composition comprising (i) alkyl guloside uronic acid salts or (ii) a mixture of alkyl guloside uronic acid salts and of alkyl mannoside uronic acid salts, according to a process as defined in any one of claims 1 to 8, said process also comprising a step e) of saponification of the ester resulting from step c).

10) The process as claimed in claim 9, wherein the saponification step e) is carried out in the presence (i) of a base M(OH).sub.x in which M is an alkali or alkaline-earth metal and x is the valency, or (ii) of a base ##STR00008## wherein each of R.sub.3 to R.sub.6 is independently a hydrogen atom, an alkyl having from 1 to 6 carbon atoms or a hydroxyalkyl having from 1 to 6 carbon atoms.

11) The process as claimed in claim 10, wherein the base is chosen from the group consisting of: sodium hydroxide, potassium hydroxide, aqueous ammonia or an alkyl(hydroxyalkyl)ammonium hydroxide.

12) The process as claimed in either one of claims 10 and 11, wherein the saponification step e) is carried out at a temperature of from 0 to 100 C.

13) A process for preparing a composition comprising (i) alkyl guloside uronic acids or (ii) a mixture of alkyl guloside uronic acids and alkyl mannoside uronic acids, according to a process as defined in any one of claims 9 to 12, said process also comprising a step of acidification f) of the salts resulting from step e).

14) The process as claimed in claim 13, wherein the acidification step f) is carried out in the presence of an acid chosen from the group consisting of: hydrochloric acid, sulfuric acid, a sulfonic acid or a sulfonic resin in its H.sup.+ form.

15) A composition obtained by means of a process as claimed in any one of claims 1 to 14.

16) The use of a composition as claimed in claim 15 as a surfactant.

17) The use as claimed in claim 16, wherein the surfactant is chosen from the group consisting of dissolving agents, hydrotropic agents, wetting agents, foaming agents, emulsifiers and/or detergents.

18) A surfactant comprising a composition as claimed in claim 15.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0057] FIG. 1 represents the tensiometric measurements carried out on the C12-C12 derivatives derived from poly(oligo)guluronate, from oligoalginate and from semi-refined alginate.

[0058] FIG. 2 represents the tensiometric measurements carried out on the NaC12 derivatives derived from poly(oligo)guluronate, from oligoalginate and from semi-refined alginate.

[0059] FIG. 3 represents the tensiometric measurements carried out on the NaC18:1 derivatives derived from semi-refined alginate.

[0060] FIG. 4 represents the tensiometric measurements carried out on the HC12 derivatives derived from poly(oligo)guluronate, from oligoalginate and from semi-refined alginate.

[0061] FIG. 5 represents the process for preparing compositions comprising alkyl(alkyl guloside)uronates of the invention starting from various algal starting materials, and prior art preparation processes.

EXAMPLES

Example 1

Preparation of a Composition Comprising Alkyl(Alkyl Guloside)Uronates from Poly(Oligo)Guluronates

C12-C12 poly(oligo)guluronate (FIG. 5)

[0062] 2013-NV-273: poly(oligo)guluronate obtained according to the process of international application WO 03/099870 [13]

TABLE-US-00002 Description Method Result Units Solids Constant weight at 103 C. 83.9 % dry/crude Mineral matter 12 h, 550 C. 25.0 % dry/crude Ratio (M/G) By calculation, proton NMR 0.2 DP By calculation 21.5

[0063] The poly(oligo)guluronate 2013-NV-273 (500 mg, 1.79 mmol CO.sub.2.sup., 1 eq) was dispersed in water (0.9 ml) and butanol (25 ml, 273 mmol, 153 eq). The 70% methanesulfonic acid solution (401 l, 3.94 mmol, 2.2 eq) was added and the mixture was refluxed with vigorous stirring. The water formed in the medium was gradually removed by azeotropic distillation. At 7 h of reaction, the mixture was cooled to ambient temperature.

[0064] Dodecanol (1.6 ml, 7.2 mmol, 4 eq) and the 70% methanesulfonic acid solution (182 l, 1.79 mmol, 1 eq) were added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar).

[0065] Once the butanol had been completely removed (1.25 h), the mixture was neutralized by adding 1M NaOH (4.5 ml) and water (20 ml) at ambient temperature and atmospheric pressure. The whole mixture was heated at 80 C. with vigorous stirring for 15 min. Once the mixture had returned to ambient temperature, the aqueous phase was separated from the organic phase. The latter was finally dried by azeotropic distillation of the water using butanol. It was possible to partially or totally remove the excess dodecanol present in the organic crude by molecular distillation.

[0066] After an optional purification by silica gel chromatography (97:3 (CH.sub.2Cl.sub.2/MeOH), a mixture of products was obtained (270 mg), the molar composition of which is: 9% dodecyl (n-dodecyl -D-mannopyranosiduronate); 2% dodecyl (n-dodecyl -D-mannofuranosiduronate); 5% n-dodecyl -D-mannofuranosidurono-6,3-lactone; 15% dodecyl (n-dodecyl -L-gulopyranosiduronate); 25% dodecyl (n-dodecyl -L-gulopyranosiduronate); 12% dodecyl (n-dodecyl -L-gulofuranosiduronate); 21% n-dodecyl -L-gulofuranosidurono-6,3-lactone; 11% n-dodecyl -L-gulofuranosidurono-6,3-lactone.

NaC12 poly(oligo)guluronate (FIG. 5)

[0067] 2014-NVR-201: poly(oligo)guluronate obtained according to the process of international application WO 03/099870 [13]

TABLE-US-00003 Description Method Result Units Solids Constant weight at 103 C. 100.0 % dry/crude Mineral matter 12 h, 550 C. 26.3 % dry/crude Ratio (M/G) By calculation, proton NMR 0.039 DP By calculation 30

[0068] The poly(oligo)guluronate 2014-NVR-201 (1.000 g, 4,2 mmol CO.sub.2.sup., 1 eq) was dispersed in water (3.0 ml) and butanol (58 ml, 634 mmol, 151 eq). The 70% methanesulfonic acid solution (940 l, 9.24 mmol, 2.2 eq) was added and the mixture was refluxed with vigorous stirring. The water formed in the medium was gradually removed by azeotropic distillation. At 7 h of reaction, the mixture was cooled to ambient temperature.

[0069] Dodecanol (3.7 ml, 16.6 mmol, 4 eq) and the 70% methanesulfonic acid solution (423 l, 4.16 mmol, 1 eq) were added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar).

[0070] Once the butanol had been completely removed (1.25 h), a 0.4M NaOH solution (37 ml) was added and the mixture was left to stir vigorously at 70 C. for 1 h. The water was then removed by freeze-drying or by azeotropic distillation with butanol. It was possible to partially or totally remove the excess dodecanol present in the crude product by solid-liquid extraction with acetone.

[0071] At the end of this treatment, a mixture of products was obtained (2.981 g), the percentage of mineral matter of which is 38.5%/crude.

HC12 poly(oligo)guluronate

[0072] A portion of this mixture of products above (816 mg) was dissolved in ice-cold water (15 ml), then a 1M hydrochloric acid solution (2.0 ml) was added. The aqueous solution was extracted with ethyl acetate (310 ml). The organic phases were combined and washed with a saturated NaCl solution (20 ml). The organic phase was dried with MgSO.sub.4 and then concentrated under vacuum. A mixture of products was obtained (195 mg), the molar composition of which is: 21% n-dodecyl -D-mannopyranosiduronic; 11% n-dodecyl -L-gulopyranosiduronic; 34% n-dodecyl -L-gulofuranosidurono-6,3-lactone; 34% n-dodecyl -L-gulofuranosidurono-6,3-lactone.

Example 2

Preparation of a Composition Comprising a Mixture of Alkyl(Alkyl Guloside)Uronates and of Alkyl(Alkyl Mannoside)Uronates

[0073] Preparation of the starting materials: The alginate extraction processes are conventionally used at CEVA [Centre for Study and Exploitation of Algae] (Ren Perez La culture des algues marines dans le monde [Cultivation of marine algae throughout the world], Ifremer: see FIG. 5). They involve acid leaching of fresh or dry algae (washing of the harvested algae with sea water, depigmentation in formol, milling, extraction with 0.2N sulfuric acid at ambient temperature, draining and rinsing of the leached algae with distilled water), followed by dissolution of the sodium alginates by increasing the pH of the medium and then solid/liquid separation in order to remove the algal residues (addition of a 1.5% Na.sub.2CO.sub.3 solution to 50 g, on a dry basis, of leached algal material according to a dry alga/1.5% Na.sub.2CO.sub.3 solution ratio of 0.025, stirring in an IKA reactor for 3 h at 55 C., cooling in a water bath with a few ice cubes in order to prevent excessive temperature differences, centrifugation for 5 minutes at 6000 rpm, solid/liquid separation). At this stage, the liquid fraction can be frozen and freeze-dried and constitutes the semi-refined alginates in the form of sodium alginates. In order to obtain refined alginates, a purification is introduced into the preceding steps. After separation of the algal residues, the latter purification step consists of precipitation of the alginic acid by reducing the pH, followed by several washes with acidic water in order to remove the co-products. Increasing the pH with Na.sub.2CO.sub.3 makes it possible to again dissolve the sodium alginates while limiting the salts, compared with the use of sodium hydroxide. Finally, a final step of freezing and then freeze-drying makes it possible to achieve the final product. In order to obtain the saturated or unsaturated oligoalginates, the alginate solution is treated enzymatically or with acid in order to reduce the degree of polymerization of the alginates from 20 to 3.

IStarting from Oligoalginates

C12-C12 oligoalginate (FIG. 5)

[0074] 2013-NV-002: oligoalginate obtained according to the process described in Example 2 and/or obtained according to the process of international application WO 98/40511 [14].

TABLE-US-00004 Description Method Result Units Solids Constant weight at 103 C. 90.1 % dry/crude Mineral matter 12 h, 550 C. 44.3 % dry/dry Ratio (M/G) By calculation, proton NMR 1.4 DP By calculation 12.7

[0075] The oligoalginate 2013-NV-002 (500 mg, 1.42 mmol CO.sub.2.sup., 1 eq) was dispersed in water (0.9 ml) and butanol (19.5 ml, 213 mmol, 150 eq). The 70% methanesulfonic acid solution (318 l, 3.12 mmol, 2.2 eq) was added and the mixture was refluxed with vigorous stirring. The water formed in the medium was gradually removed by azeotropic distillation. At 7 h of reaction, the mixture was cooled to ambient temperature.

[0076] Dodecanol (1.3 ml, 5.8 mmol, 4 eq) and the 70% methanesulfonic acid solution (145 l, 1.43 mmol, 1 eq) were added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar).

[0077] Once the butanol had been completely removed (1.25 h), the mixture was neutralized by adding 1M NaOH (3.2 ml) and water (20 ml) at ambient temperature and atmospheric pressure. The whole mixture was heated at 80 C. with vigorous stirring for 15 min. Once the mixture had returned to ambient temperature, the aqueous phase was separated from the organic phase. The latter was finally dried by azeotropic distillation of the water using butanol. It was possible to partially or totally remove the excess dodecanol present in the organic crude by molecular distillation.

[0078] After an optional purification by silica gel chromatography (97:3 CH.sub.2Cl.sub.2/MeOH), a mixture of products was obtained (231 mg), the molar composition of which is: 29% dodecyl (n-dodecyl -D-mannopyranosiduronate); 6% dodecyl (n-dodecyl -D-mannofuranosiduronate); 12% n-dodecyl ,-D-mannofuranosidurono-6,3-lactone; 23% dodecyl (n-dodecyl ,-L-gulopyranosiduronate); 9% dodecyl (n-dodecyl -L-gulofuranosiduronate); 21% n-dodecyl ,-L-gulofuranosidurono-6,3-lactone.

NaC12 oligoalginate (FIG. 5)

[0079] The oligoalginate 2013-NV-002 (1.000 g, 2.84 mmol CO.sub.2.sup., 1 eq) was dispersed in water (2.0 ml) and butanol (39 ml, 426 mmol, 150 eq). The 70% methanesulfonic acid solution (634 l, 6.24 mmol, 2.2 eq) was added and the mixture was refluxed with vigorous stirring. The water formed in the medium was gradually removed by azeotropic distillation. At 7 h of reaction, the mixture was cooled to ambient temperature.

[0080] Dodecanol (2.5 ml, 11.2 mmol, 4 eq) and the 70% methanesulfonic acid solution (290 l, 2.85 mmol, 1 eq) were added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar).

[0081] Once the butanol had been completely removed (1.25 h), a 0.4M NaOH solution (25 ml) was added and the mixture was left to stir vigorously at 70 C. for 1 h. The water was then removed by freeze-drying or by azeotropic distillation with butanol. It was possible to partially or totally remove the excess dodecanol present in the crude product by solid-liquid extraction with acetone.

[0082] At the end of this treatment, a mixture of products was obtained (2.532 g), the percentage of mineral matter of which is 41.8%/crude.

HC12 oligoalginate

[0083] A portion of this mixture of products above (837 mg) was dissolved in ice-cold water (15 ml) and then a 1M hydrochloric acid solution (2.0 ml) was added. The aqueous solution was extracted with ethyl acetate (310 ml). The organic phases were combined and washed with a saturated NaCl solution (20 ml). The organic phase was dried with MgSO.sub.4 and then concentrated under vacuum. A mixture of products was obtained (251 mg), the molar composition of which is: 32% n-dodecyl -D-mannopyranosiduronic; 13% n-dodecyl -L-gulopyranosiduronic; 29% n-dodecyl -L-gulofuranosidurono-6,3-lactone; 26% n-dodecyl -L-gulofuranosidurono-6,3-lactone.

IIStarting from Semi-Refined Alginate

C12-C12 semi-refined alginate (FIG. 5)

[0084] 2013-XS-137: the semi-refined alginate derived from Laminaria digitata obtained in accordance with the process described in Example 2.

TABLE-US-00005 Description Method Result Units Solids Constant weight at 103 C. 94.9 % dry/crude Mineral matter 12 h, 550 C. 47.0 % dry/dry Mannuronic and Methanolysis 29.2 % dry/dry guluronic acid content Glucose content Methanolysis 10.9 % dry/dry Xylose content Methanolysis <0.5 % dry/dry Fucose content Methanolysis 2.1 % dry/dry Ratio (M/G) By calculation, proton NMR 2.6

[0085] The semi-refined alginate 2013-XS-137 derived from Laminaria digitata (1.000 g, 2.15 mmol sugar units, 1 eq) was dispersed in water (30 ml) and the 70% methanesulfonic acid solution (1.09 ml, 10.7 mmol, 5 eq) was added. The mixture was refluxed with vigorous stirring. At 8 h of reaction, butanol (30 ml, 328 mmol, 153 eq) was added and the mixture was left at reflux with vigorous stirring. The water present in the medium was gradually removed by azeotropic distillation.

[0086] After a further 15 h of reaction, and once the mixture had returned to ambient temperature, dodecanol (1.92 ml, 8.6 mmol, 4 eq) was added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar).

[0087] Once the butanol had been completely removed (1.25 h), the mixture was neutralized by adding 1M NaOH (3.55 ml) and water (30 ml) at ambient temperature and atmospheric pressure. The whole mixture was heated at 80 C. with vigorous stirring for 15 min. Once the mixture had returned to ambient temperature, the aqueous phase was separated from the organic phase. The latter was then washed with water (30 ml) by stirring at 80 C. for 15 min. The organic phase was recovered and then dried by azeotropic distillation of the water using butanol. It was possible to partially or totally remove the excess dodecanol present in the crude product by molecular distillation.

[0088] After an optional purification by silica gel chromatography (97:3 then 96:4 then 90:10 CH.sub.2Cl.sub.2/MeOH), a mixture of products was obtained (377 mg), the weight composition of which is: dodecyl (n-dodecyl -D-mannofuranosiduronate), n-dodecyl ,-D-mannofuranosidurono-6,3-lactone, dodecyl (n-dodecyl -L-gulofuranosiduronate) and n-dodecyl ,-L-gulofuranosidurono-6,3-lactone 35%, dodecyl (n-dodecyl -D-mannopyranosiduronate) and dodecyl (n-dodecyl ,-L-gulopyranosiduronate) 25%, 14% n-dodecyl L-fucose, 26% n-dodecyl ,-D-glucopyranose.

NaC12 semi-refined alginate (FIG. 5)

[0089] The semi-refined alginate 2013-XS-137 derived from Laminaria digitata (2.000 g, 4.3 mmol sugar units, 1 eq) was dispersed in water (60 ml) and the 70% methanesulfonic acid solution (2.19 ml, 21.5 mmol, 5 eq) was added. The mixture was refluxed with vigorous stirring. At 8 h of reaction, butanol (60 ml, 656 mmol, 152 eq) was added and the mixture was left at reflux with vigorous stirring. The water present in the medium was gradually removed by azeotropic distillation.

[0090] After a further 15 h of reaction, and once the mixture had returned to ambient temperature, dodecanol (3.8 ml, 17 mmol, 4 eq) was added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar).

[0091] Once the butanol had been completely removed (1.25 h), a 0.2M NaOH solution (60 ml) was added and the mixture was left to stir vigorously at 70 C. for 1 h. The water was then removed by freeze-drying or by azeotropic distillation with butanol. It was possible to partially or totally remove the excess dodecanol present in the crude product by solid-liquid extraction with acetone.

[0092] At the end of this treatment, a mixture of products was obtained (3.592 g), the percentage of mineral matter of which is 42.4%/crude.

HC12 semi-refined alginate

[0093] A portion of this mixture of products above (1.081 g) was dissolved in ice-cold water (15 ml) and then a 1M hydrochloric acid solution (2.0 ml) was added. The aqueous solution was extracted with ethyl acetate (310 ml). The organic phases were combined and washed with a saturated NaCl solution (20 ml). The organic phase was dried with MgSO.sub.4 and then concentrated under vacuum. A mixture of products was obtained (138 mg), the weight composition of which is: n-dodecyl D-mannuronic and L-guluronic derivatives 67%, n-dodecyl L-fucose and n-dodecyl ,-D-glucopyranose 33%.

NaC18:1 semi-refined alginate (FIG. 5)

[0094] The semi-refined alginate 2013-XS-137 derived from Laminaria digitata (2.000 g, 4.3 mmol sugar units, 1 eq) was dispersed in water (60 ml) and the 70% methanesulfonic acid solution (2.19 ml, 21.5 mmol, 5 eq) was added. The mixture was refluxed with vigorous stirring. At 8 h of reaction, butanol (60 ml, 656 mmol, 152 eq) was added and the mixture was left at reflux with vigorous stirring. The water present in the medium was gradually removed by azeotropic distillation. After a further 15 h of reaction, and once the mixture had returned to ambient temperature, oleyl alcohol (5.4 ml, 17 mmol, 4 eq) was added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar). Once the butanol had been completely removed (1.25 h), a 0.2M NaOH solution (60 ml) was added and the mixture was left to stir vigorously at 70 C. for 1 h. The water was then removed by freeze-drying or by azeotropic distillation with butanol. It was possible to partially or totally remove the excess oleyl alcohol present in the crude product by solid-liquid extraction with acetone. At the end of this treatment, a mixture of products was obtained (3.418 g), the percentage of mineral matter of which is 44.1%/crude.

IIIStarting from Refined Alginate

C12-C12 refined alginate (FIG. 5)

[0095] 2013-NV-277: refined alginate derived from Laminaria digitata obtained according to the process described in Example 2.

TABLE-US-00006 Description Method Result Units Solids Constant weight at 103 C. 94.2 % dry/crude Mineral matter 12 h, 550 C. 37.2 % dry/dry Ratio (M/G) By calculation, proton NMR 2.6 DP By calculation 362

[0096] The refined alginate 2013-NV-277 derived from Laminaria digitata (1.000 g, 2.38 mmol CO.sub.2.sup., 1 eq) was dispersed in water (30 ml) and the 70% methanesulfonic acid solution (1.21 ml, 11.9 mmol, 5 eq) was added. The mixture was refluxed with vigorous stirring. At 8 h of reaction, butanol (33 ml, 361 mmol, 152 eq) was added and the mixture was left at reflux with vigorous stirring. The water present in the medium was gradually removed by azeotropic distillation. After a further 15 h of reaction, and once the mixture had returned to ambient temperature, dodecanol (2.12 ml, 9.5 mmol, 4 eq) was added. The mixture was stirred at 70 C. under reduced pressure (up to 5 mbar). Once the butanol had been completely removed (1.25 h), the mixture was neutralized by adding 1M NaOH (3.95 ml) and water (30 ml) at ambient temperature and atmospheric pressure. The whole mixture was heated at 80 C. with vigorous stirring for 15 min. Once the mixture had returned to ambient temperature, the aqueous phase was separated from the organic phase. The latter was finally dried by azeotropic distillation of the water using butanol. It was possible to partially or totally remove the excess dodecanol present in the organic crude by molecular distillation. After an optional purification by silica gel chromatography (97:3 CH.sub.2Cl.sub.2/MeOH), a mixture of products was obtained (387 mg), the molar composition of which is: 8% dodecyl (n-dodecyl -D-mannofuranosiduronate), 4% n-dodecyl -D-mannofuranosidurono-6,3-lactone, 11% dodecyl (n-dodecyl -L-gulofuranosiduronate), 4% n-dodecyl -L-gulofuranosidurono-6,3-lactone, 7% n-dodecyl -L-gulofuranosidurono-6,3-lactone, 48% dodecyl (n-dodecyl -D-mannopyranosiduronate), 5% dodecyl (n-dodecyl -L-gulopyranosiduronate), 13% dodecyl (n-dodecyl -L-gulopyranosiduronate).

Example 3

Tensiometric Measurements of the Compositions of the Invention

Interfacial Tension

[0097] The interfacial tension measurements were carried out using a Krss tensiometer with a horizontally suspended platinum ring. Before each measurement, the ring was meticulously cleaned and flame-dried. The sample bucket is a cylindrical glass container placed in a thermoregulated chamber. The sample solutions were prepared with sunflower oil. The interfacial tension measurements were carried out between Milli-Q water and the sample solutions in oil.

[0098] The various batches of C12-C12 derivative surfactants obtained at the end of the purification by chromatography were characterized by interfacial tension measurements between water and sunflower oil.

[0099] The results represented in FIG. 1 show that the interfacial tension is clearly decreased regardless of the surfactant batch. However, the batch obtained from semi-refined alginate is the one which makes it possible to most efficiently reduce the tension. Indeed, it makes it possible to achieve the same tension values at concentrations that are 10 times lower; for example, 7.0 mN/m at 0.5 g/l instead of 5.0 g/l.

Surface Tension

[0100] The surface tension measurements were carried out using a Krss tensiometer with a horizontally suspended platinum ring. Before each measurement, the ring was meticulously cleaned and flame-dried. The sample bucket is a conical PTFE container placed in a thermoregulated chamber. The sample solutions were prepared with Milli-Q water and continually stirred using a magnetic bar before each measurement.

[0101] The various batches of NaC12 derivative surfactants obtained at the end of the solid-liquid extraction were characterized by surface tension measurements.

[0102] The results represented in FIG. 2 show first of all that all the batches of surfactants make it possible to efficiently reduce the surface tension of the water, since values of between 25 and 30 mN/m were measured at the respective critical micelle concentrations (CMGs). However, very different CMC values are obtained depending on the batches. Specifically, the batch derived from oligoalginate has the lowest value (1.9 g/l), whereas that obtained from poly(oligo)guluronate has the highest value (5.0 g/l). The batch derived from semi-refined alginate (L. digitata) has an intermediate CMC value: 4.7 g/l. It is, however, possible to note that the latter is the one which makes it possible to most efficiently reduce the surface tension, since a tension of 25.7 mN/m was measured at the CMC. It is also important to note that, for all the concentration values, the lowest surface tension values were measured with the batch obtained from semi-refined alginate.

[0103] The batch of NaC18:1 derivative surfactants, derived from semi-refined alginate, obtained at the end of the solid-liquid extraction was characterized by surface tension measurements (FIG. 3).

[0104] The results represented in FIG. 3 show that the batch makes it possible to efficiently reduce the surface tension. A CMC of 0.55 g/l and a .sub.CMC of 30 mN/m were measured.

[0105] The various batches of HC12 derivative surfactants obtained after acidification of the NaC12 derivatives and removal of the inorganic salts were characterized by surface tension measurements (FIG. 4).

[0106] The results represented in FIG. 4 show first of all that all the batches of surfactants make it possible to efficiently reduce the surface tension of water since values of less than 30 mN/m were measured at the CMCs. The batch obtained from poly(oligo)guluronate has a CMC of 0.12 g/l with a .sub.CMC of 28.8 mN/m. The results obtained with the batch derived from oligoalginate are slightly better, since the CMC is 0.11 g/l and the .sub.CMC is 27.6 mN/m. Finally, the batch obtained from semi-refined alginate (L. digitata) makes it possible to obtain the lowest CMC with a value of 0.04 g/l and a .sub.CMC of 29 mN/m. It is also important to note that, for the concentrations of less than 0.008 g/l, the lowest surface tension values were measured with the batch obtained from poly(oligo)guluronate.

REFERENCE LIST

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