EP1945677A1

EP1945677A1 - Product resulting from the grafting of fatty chains to ulvans and use of said product as a surfactant

Info

Publication number: EP1945677A1
Application number: EP06820311A
Authority: EP
Inventors: Michèle Ranson; Gilles Gutierrez; Dominique Brault; Hervé LE DEIT; Xavier Pages-Xatart-Pares; Carine Alfos
Original assignee: JAVENECH; Environmental Protection Engineering Sa; ICP Institute for Cellular Pharmacology
Current assignee: JAVENECH; Environmental Protection Engineering Sa; ICP Institute for Cellular Pharmacology
Priority date: 2005-10-19
Filing date: 2006-10-18
Publication date: 2008-07-23
Also published as: US20090299053A1; FR2892119B1; WO2007045795A1; FR2892119A1

Abstract

The invention relates to a product resulting from the esterification or transesterification grafting of saturated or unsaturated, linear or branched fatty chains or mixtures of fatty chains containing between 8 and 28 carbon atoms to at least part of the hydroxyl functions of an ulvan-type polysaccharide in acid form or in the form of a mono- or di-valent salt, such as a sodium salt. The invention also relates to the method of preparing the aforementioned product. The invention further relates to the uses of said product, for example as a surfactant.

Description

Product resulting from the grafting of fatty chains on ulvans and its use as a surfactant.

The present invention relates to novel ulvan derivatives, their methods of preparation and their uses, especially as surfactants.

Seaweed is known to be an important source of polysaccharides with gelling and thickening properties, widely used for food and non-food purposes. Ulvans are extracted from ulvae or enteromorphs. These green algae are part of the phyllum chlorophytes and order ulvals characterized by a thallus tube (enteromorph) or double layer cell (ulva). There are several ulva species including Ulva lactuca, Ulva rigida, Ulva armoricana and Ulva rotundata, as well as several enteromorph species such as Enteromorpha compressa, Enteromorpha intestinalis and

Enteromorpha ramulosa.

Various methods of extracting ulvans from algae have been described in the literature. Most particularly, the process described by M. LAHAYE, B.

RAY, S. BAUMBERGER, B. QUEMENER and M. A.V. AXELOS in

Hydrobiologia 326/327: 473-480, 1996.

According to this method, a fresh or dried seaweed is crushed then dissolved in water and refluxed for one hour. The suspension is then centrifuged and reextracted a second time according to the same protocol. The two supernatants are then combined and the ulvans are precipitated with ethanol. After filtration, the ulvans are then dried in an oven. The yields are of the order of 10% relative to the dry matter of the starting algae. Ulvans are sulfated anionic polysaccharides soluble in water. They are located at the level of the cell in the cell wall.

The literature (Lahaye M., Jegou D. Buleon A. Carbohydr Res 1994;

262: 115) indicates that ulvans are of the family of sulfated xyloramnoglucoronan or sulfated glucoronorhamnoxyloglycan. The sugars in the composition of ulvans are sulphated rhamnose in position 3, galactose, glucose and xylose for neutral sugars and glucuronic acid and iduronic acid for acid sugars. (Lahaye M., Alvarez-Cabal Cimadevilla E., Kuhlenkamp R., Quemener B. Lognae V., Dion P. Journal of Applied Phycology 11: 1-7, 1999)

The xylose may be partially sulphated.

The relative proportion of sugars varies according to the place of harvest of the ulva, the species and also the time of harvest in the year. The following table shows the levels of sugars found in different species of ulva:

Green algae of the ulva family, including the species produced by green tides, contain ulvans, which are water-soluble complex polysaccharides comprising both uronic acids and sulphated monosaccharides. The chemical structure of ulvans is based on the repetition of different disaccharide units. The disaccharide units are predominantly composed of 3-sulfate sodium ulvanobiuronate type A comprising 3-sulfate rhamnose bound to glucuronic acid by a 1 → 4 type binding and sodium 3-sulfate sodium ulvanobiuronate comprising 3-sulphate rhamnose bound to Iduronic acid by a type 1 → 4 bond:

The two disaccharide units are shown below.

> Disaccharide unit of 3-sulphate ulvanobiuronic acid A

1 2

[-> 4) -β-D-GlucpA- (l-> 4) -α-L-Rha / 73-suIfate- (l->]

> Disaccharide unit of 3-sulphate ulvanobiuronic acid B

[-> 4) - α-L-IdopA- (1 → 4) -α-L-Rhap 3-sulphate (1 ->) The other minority sugars (xylose, galactose and glucose) are inserted in the chain indefinitely and certainly vary depending on the species and the locations and times of the year.

The polysaccharide may also carry side chains whose structure has not been clearly identified.

The literature cites a large number of documents relating to the synthesis or use of polyose esters. In particular, US Pat. Nos. 4,517,360 and 3,963,699 describe polyose esters derived from mono- and disaccharose or sucrose, xylitol or sorbitol-type polyols, and French patent 2,009,161, which describes esters. polyols from natural starches. The international application WO 92/13006 also describes complex products based on polyoses and fatty acids resulting from the reaction of at least one polyose with at least one fatty acid, especially in the form of halide or anhydride. However, none of the documents in the literature suggests using as polyose an ulvane-type polysaccharide and, even less, the interest as a surfactant presented by the esterification product of such a polysaccharide and the additional interest that would present the valorization, in the form of products with surface-active character, of the algae of the ulva type considered essentially to date rather like nuisances, their proliferation resulting mainly from pollution.

Indeed, the phenomenon of green tides affects each year some beaches, including Brittany (Côtes d'Armor) and involves significant olfactory and visual nuisances. These hamper tourism activity (second economic sector of the department of Côtes d'Armor) and generate high collection costs. It was from the 1980s that green algae collections were necessary in order to maintain the tourist activity of the sites and to compensate for the olfactory and visual nuisances caused by this phenomenon. In 2000, more than 75,000 m3 of green algae were collected on the Brittany coast. The algae are then stored in uncontrolled landfills, or directly spread on farmland. The factors responsible for green tides are now known. They located at the level of watersheds which support an intensive agriculture generating nutritive salts, which end up being in excess in the coastal waters.

Thus, an additional advantage of the invention is to value a product usually considered a nuisance.

The invention provides novel products which result directly from grafting by esterification or transesterification of fatty chains on ulvans.

The particularly advantageous properties of the products of the invention make it possible to envisage their use in many fields, as surface-active agents, in particular with a view to the preparation of emulsions. As will be apparent from the description and examples which follow, properties are particularly interesting in various fields, especially in the field of cosmetics, because of the particularly soft and substantive touch of these products as well as their emulsifying and moisturizing properties, but also in totally different areas such as the recovery or dispersion of hydrocarbons.

More specifically, according to one of its essential characteristics, the invention relates to a product resulting from grafting by esterification or transesterification on at least part of the hydroxyl functions of an ulvane-type polysaccharide in acid form or in the form of a salt. a mono- or divalent cation, especially a sodium salt of fatty chains or mixtures of fatty chains containing 8 to 28 carbon atoms, said fatty chains being saturated or unsaturated, linear or branched.

This product, hereinafter referred to as "polyose-ester", is derived from the reaction of polysaccharides (ulvans) extracted from algae of the ulva or enteromorphic type or from mixtures of these two types of algae with compounds comprising fatty chains containing between 8 and 28 carbon atoms, these chains may be saturated or unsaturated, linear or branched.

For the preparation of ulvan by extraction from ulva, reference is made to the extraction method described in Carbohydrate Research 274 (1995) 251-261 or in Hydrobiologia 326/327; 473-480, 1996. In general, the extracts used according to the invention are advantageously prepared by extraction in aqueous medium of ulva and / or enteromorphs, the extraction step being advantageously followed by an ultrafiltration step.

By grafting rate of the fatty chains on the ulvan skeleton is meant in the sense of the invention, the proportion by weight of fatty acid relative to the starting polyose.

Those skilled in the art will understand that depending on the nature of the fatty chains and the degree of grafting of these chains on the polysaccharide backbone, one will obtain properties that will vary from one product to another. It will thus be possible to vary the rheological, solubilizing, gelling, thickening, emulsifying, coemulsifying and organoleptic properties, as well as solubility, lipophilicity, texture, color, surface tension, interfacial tension and micellar concentration. critical solution, the saponification index, the iodine number, the acidity of the products of the invention.

By way of example and to facilitate understanding of the type of reaction involved, two chemical formulas of grafted disaccharide units are given below, each R group representing either a carboxylated fatty chain or a hydrogen and being independent of the others, as long as the disaccharide unit contains at least one fatty chain.

> Disaccharide unit grafted with 3-sulphate ulvanobiuronic acid A

Disaccharide unit grafted with 3-sulphate ulvanobiuronic acid B

According to a second essential characteristic of the invention, it relates to a process for preparing the products and product mixtures referred to above.

In general, this process comprises an esterification or transesterification step using at least a part of the hydroxyl functions of an ulvane-type polysaccharide or of one of its salts obtained by extraction from a type of algae. ulve. Different variants of this process may be envisaged, in particular to take into account the specific character of the backbone on which it is desired to graft the fatty chains and the degree of grafting that it is desired to achieve, a rate which may vary in particular with the field of application. referred. Thus, the various processes developed by the inventors of the present invention are all inspired by methods described in the literature taking into account both the specific character of the polysaccharide substrate and the intended application which may require more or less purity. important product and / or a grafting rate of fatty chains more or less important on the polysaccharide backbone.

Thus, it is possible to envisage different process variants whose common point will be to carry out an esterification or a transesterification of fatty chains on an ulva or enteromorph extract in solid form generally containing at least 85% by weight of ulvans, preferably at least 95%, this extract may in particular be obtained according to the protocol described in Hydrobiologia 326/327: 473-480.1996.

According to a first variant of the process of the invention, the grafting will be carried out by esterification, in particular by means of an acid chloride of a fatty-chain acid comprising from 8 to 28 carbon atoms. Such a method has the advantage of being able to prepare highly grafted products in which the proportion by weight of fatty acid relative to the polyose is at least 10%, preferably between 50 and 75%. However, such a process proves to be relatively aggressive with respect to the reactants and it will generally be preferred to use a process proceeding by transesterification, a process that can be carried out under milder conditions while respecting the skeleton particularly well, which allows to access products, of superior purity, thus not colored.

As indicated above, the preparation of the products of the invention is preferably used for a transesterification process.

This transesterification will advantageously be carried out starting from esters of C8 to C28 fatty acids and of C1 to C6 alcohols or of mixtures of such esters and will make it possible to graft the fatty chains originating from said esters by means of a ester-type bond on at least a portion of the hydroxyl groups of ulvan.

By way of examples of fatty esters which can be used to carry out such a transesterification, mention may be made of methyl, ethyl, isopropyl, pentyl, methyl, propyl, butyl or hexyl esters of fatty acids such as lauric, oleic and capric acid. myristic, palmitic, palmitoleic, linoleic, linolenic, arachidic, as well as mixtures of these different esters.

These esters may have different sources, in particular plant or animal sources. In particular, vegetable oils of soya, peanut, sunflower, rapeseed, sesame, olive, palm, palm kernel, copra, flax, castor oil, animal fish oils, butters , lard and tallow.

According to a first variant, the transesterification may be carried out in a solvent medium.

By way of nonlimiting examples of solvents used in such a transesterification process, mention may be made of dimethylsulfoxide, diethylsulfoxide, dibutylsulfoxide, dibenzylsulfoxide, N, N-dimethylformamide, N, N-diethylformamide and N, N-diphenylformamide. . The solvent used to carry out the transesterification will then have to be removed, for example by evaporation. The removal of the solvent will have to be more or less total, depending on the intended use for the product of the invention.

According to another preferred variant of the invention, the product may be prepared by transesterification without a solvent. Such a process proves to be significantly more advantageous than the previous one for industrial purposes since it is less expensive and avoids the problems related to the use of the solvent and the need, in certain cases, to eliminate all of the solvent.

In general, the non-solvent transesterification processes developed in the context of the present invention are based on the processes described in US Pat. Nos. 4,517,360 and 963,699, but have required a number of related adaptations. in particular to the nature of the specific substrate used for the grafting of the ester functions in the case of the products of the invention. By transesterification in a non-solvent medium is meant within the meaning of the invention that the reaction, itself, transesterification is carried out in the absence of solvent. However, the recovery of the product formed during the reaction will require the use of at least one solvent medium in one or more extraction steps, as is apparent from the detailed description which follows.

The transesterification process without solvent is advantageously carried out by bringing the polysaccharide into contact with at least one fatty ester as defined above and at least one compound based on soaps, advantageously at least one compound based on alkaline metal fatty acid soaps saturated or unsaturated.

The presence of this or these soaps greatly improves the intersolubility between the two reagents ulvan and fatty ester.

By "alkaline metal soaps of fatty acids" is meant alkali metal soaps of fatty acids having from 8 to 22 carbon atoms. Examples of alkali metal soaps of fatty acids are in particular the sodium, lithium, potassium, rubidium and cesium salts of capric, lauric, oleic, myristic, palmitic, licanic, parinaric, arachidic or stearic acids, and as their mixtures. The reagents described above for the preparation of the transesterification product form a heterogeneous mixture. The precise ratios of reagents can be freely determined either by experimentation or with the aid of the examples given below. In general, the starting reagent mixture comprises from about 5% to about 75%, preferably from about 15% to about 35% by weight of polyoses derived from ulva, from about 20% to about 90%, preferentially from about 40% to about 70% by weight of fatty acid esters and from about 1% to about 35%, preferably from about 10% to about 20% by weight of alkali metal fatty acid soaps.

The heterogeneous mixture is heated at a temperature advantageously between about 70 ^° C. and about 180 ^° C., preferably between about 100 ^° C. and 150 ^° C. under a pressure of about 0.1 mm of mercury to about 760 mm of mercury, preferably of 0.5 to 100 mm of mercury. With this range of temperatures and pressures, a homogeneous mixture of partially or fully esterified polyoses and unreacted starting reagents is formed after a time varying from about 1 hour to 18 hours, preferably a time varying from about 4 hours to 10 hours.

As a result of this reaction step, an organic solvent which can be either soluble or insoluble in water and whose effect is to modify the viscosity of the reaction medium is advantageously added.

The addition of this solvent makes it possible to form a more fluid organic phase. The amount of solvents to be added depends greatly on the viscosity of the reaction medium at the end of the reaction step. The reaction medium is then acidified.

By way of example, there may be mentioned several acids that may be used: hydrochloric acid, sulfuric acid, citric acid, lactic acid, acetic acid, formic acid and mixtures thereof.

The purpose of this treatment with an acid is to allow the elimination of the metal soap or so by neutralization.

Then, a fast and simple treatment makes it possible to provide a family of polyose-esters. This treatment involves adding water to form a gel.

The gel formed is separated from the reaction medium and, if necessary, it can be dried by conventional drying techniques to give a family of polyose-esters. The family of polyose-esters thus obtained is characterized by compounds with a fatty ester / polyose proportion which, for example, may be between 5 and 85% by weight, preferably between 25 and 70%. These products are easily soluble in water and give compounds with interesting properties, including moisturizing, emulsifying, co-emulsifying and imparting a soft and substantive touch in solution.

The transesterification method in a non-solvent medium as defined above makes it possible to recover at least a portion of the polyose-esters formed in the transesterification reaction in the form of an aqueous gel.

This method has the advantage of being particularly simple.

However, depending on the length of the fatty chains fixed on the skeleton and / or the degree of grafting, there are cases where, to recover as quantitatively as possible all the polyoses-esters formed, it will be interesting to make follow the step of extraction in gel form in an aqueous medium of a second extraction step of the polysaccharides optionally contained in the organic phase formed above.

This additional extraction step intended for better recovery of all the polyosesters-esters formed will be particularly advantageous when the fatty chains are long or when the degree of grafting of these chains on the polysaccharide backbone is high. This will be particularly the case when the acid chains will have 16 or more carbon atoms or when the degree of grafting will be greater than or equal to 30%.

Such a treatment leads to the separation of two families of polyose-esters, one of which has a higher average grafting rate than the other.

In such a process, a method identical to that described above in which the transesterification is carried out in a non-solvent medium, preferably in the presence of at least one metallic soap, is carried out first of all as defined above. -above. Then, as in the previous method, the metal soap is removed and the viscosity of the medium is adjusted before precipitating a first family of polyose-esters in gel form. Then, the gel formed is separated from the reaction medium and, if necessary, it can be dried by conventional drying techniques and thus gives a first family of polyose-esters.

The remaining reaction medium is washed one or more times with water and the washings are extracted with a solvent of alcohol type partially soluble in water or insoluble in water, for example 1-butanol, 2 butanol, pentanol, hexanol, cyclohexanol. The alcoholic phase is then dried and gives a second family of polyosesters, which has a grafting rate higher than that of the first. The first family of polyose-esters is characterized by less grafted compounds, where, by way of example, the proportion fatty ester / polyose can be between 5 and 75% by weight, preferably between 20 and 60%.

This family is more hydrophilic and gives compounds with interesting properties, including emulsifying, co-emulsifying and imparting a soft and substantive touch in solution.

The second family is characterized by compounds having a low grafting rate with a high fatty ester / polyose ratio, included, for example, between 15 and 100% by weight, preferably between 40 and 90%. This family has very marked moisturizing properties.

The present invention further relates to the use of the polyose-fatty ester product as an emulsifying or co-emulsifying agent in the context of topical cosmetic or pharmaceutical applications.

In this use, any proportion of the above product may be used.

Particularly preferred proportions by weight for which an emulsifying or co-emulsifying effect is obtained vary between 0.1% and 10%. Preferred proportions are of the order of 1 to 3% by weight relative to the total weight of the composition to be emulsified.

The invention also relates to the use of the polyose-fatty ester product as a film-forming agent, in particular providing a soft touch in the context of cosmetic or pharmaceutical applications. In this use, any proportion of the aforementioned complex product can be used.

Particularly preferred proportions by weight for which a film-forming and mild effect is obtained vary between 0.1% and 25%. Preferred proportions are of the order of 1 to 3% by weight relative to the total weight of the composition to be emulsified.

The invention also relates to the use of the product as a moisturizing agent in the context of cosmetic or pharmaceutical applications. In this use, any proportion of the product of the invention can be used. Particularly preferred proportions by weight for which a hydrating effect is obtained vary between 0.1% and 10%. Preferred proportions are of the order of 1 to 3% by weight relative to the total weight of the composition.

The invention also relates to an emulsifying composition, characterized in that it contains as an emulsifying or coemulsifying agent a polyose-fatty ester complex product as defined above.

The invention also relates to a moisturizing composition, characterized in that it contains, as hydrating agent, a polyose-fatty ester product as defined above.

The present invention also relates to a film-forming composition, characterized in that it contains as a film-forming agent a polyose-fatty ester, as defined above.

Because of their remarkable surface-active properties, the products of the invention can also be used in a totally different field, namely the recovery or the dispersion of hydrocarbons, as well on soils as on expanses of water. In such applications, the product of the invention will be used as a surfactant for emulsifying or dispersing the fat phases, at concentrations conventionally used for this purpose.

EXAMPLES

In all the examples which follow, the treated ulva extract is obtained following the protocol described in Hydrobiologia 326/327: 473-480, 1996. (Extraction in a hot aqueous medium and ultrafiltration) Example 1

Preparation of a highly esterified polyose ester

300 g of ulve polysaccharides diluted in 5 liters of pyridine are mixed with 1 kg of lauryl chloride at a temperature of 130 ^° C. for 2 hours. The mechanical stirring is set at 400 rpm. The reaction is then stopped by the addition of a mixture of alcohol and water. The whole is filtered under vacuum and washed with ethanol and acetone. The compound obtained is highly grafted but also very colored, which proves a certain degradation.

Example 2

Preparation of two families of polyose-esters from methyl oleate by transesterification without solvent

The polyoses from ulva (500 grams), methyl oleate (1200 grams), sodium oleate (225 grams) and lithium oleate (53 grams) are mixed in a 4 liter reactor. The mixture is heated at 150 ^° C. for 6 h with mechanical stirring (600 rpm) and under reduced pressure. The reaction medium is dissolved in butanone. The soaps are neutralized with lactic acid. Distilled water is added and a gelled phase is formed which is easily separated from the reaction medium. This gelled phase is dried and constitutes the first family of polyose-esters. At the same time, the remainder of the reaction medium is washed several times with distilled water and then the washing water is extracted with butanol. The butanol phase is dried and contains the second family of polyose-esters. This second family contains the most grafted polyoses. Distillation of the remaining organic phase allows the recovery of butanone, fatty acids and methyl esters for recycling.

Example 3

Preparation of two families of polyose-esters from methyl laurate by transesterification without solvent Ulva polyoses (200 grams), methyl laurate (360 grams), sodium oleate (117 grams) and lithium oleate (27.7 grams) are mixed in a 2 liter reactor. The mixture is heated at 100 ^° C. for 6 h with mechanical stirring (600 rpm) and under reduced pressure. The reaction medium is dissolved in butanone. The soaps are neutralized with lactic acid. Distilled water is added and a gelled phase is formed which is easily separated from the reaction medium. This gelled phase is dried and constitutes the first family of polyose-esters. At the same time, the remainder of the reaction medium is washed several times with distilled water and then the washing water is extracted with butanol. The butanol phase is dried and contains the second family of polyose-esters. This second family contains the most grafted polyoses. Distillation of the remaining organic phase allows the recovery of butanone, fatty acids and methyl esters for recycling.

Example 4

Preparation of a family of polyose-esters from methyl oleate by transesterification without solvent

Ulva polyoses (500 grams), methyl oleate (1200 grams), sodium oleate (225 grams) and lithium oleate (53 grams) were mixed in a 4 liter reactor. The mixture is heated at 150 ^° C. for 6 h with mechanical stirring (600 rpm) and under reduced pressure. The reaction medium is dissolved in butanone. The soaps are neutralized with lactic acid. Distilled water is added and the gel-containing aqueous phase is separated off. This phase is dried and constitutes the complex family of polyose-esters. Distillation of the remaining organic phase allows the recovery of butanone, fatty acids and methyl esters for recycling. The polyose-esters have a fatty acid / polyose proportion which is close to 55% by weight.

Example 5

Preparation of a family of polyose-esters from methyl laurate by transesterification without solvent Polyoses from ulva (200 grams), methyl laurate (360 grams), sodium oleate (117 grams) and lithium oleate (27.7 grams) were mixed in a 2 liter reactor. The mixture is heated at 100 ^° C. for 6 h with mechanical stirring (600 rpm) and under reduced pressure. The reaction medium is dissolved in butanone. The soaps are neutralized with lactic acid. Distilled water is added and the gel-containing aqueous phase is separated off. This phase is dried and constitutes the complex family of polyose-esters. Distillation of the remaining organic phase allows the recovery of butanone, fatty acids and methyl esters for recycling. The polyose-esters have a fatty acid / polyose proportion which is close to 40% by weight.

Example 6

Simple formulation for applications as a shampoo

Texapon NSO (sodium laureth sulfate) 20.0% by weight Tegobetaine F 50 (cocamidopropylbetaine) 5% by weight Polyose-ester complex derived from Example 4: 1.5% by weight NaCl Amount sufficient for the desired viscosity Water; to complete at 100.0% weight

The shampoo is homogeneous, stable, soft to the touch after rinsing.

A shampoo in all respects similar but which does not contain the complex of Example 4 gives a dry touch after rinsing.

Example 7

Simple formulation for application as a shower gel

Texapon NSO (sodium laureth sulfate) 20.0%

Tegobetaine F 50 (cocamidopropylbetaine) 5%

Polyose ester complex of Example 5: 2.5%

NaCl SUFFICIENT QUANTITY FOR Viscosity

Water: to complete at 100.0% The shower gel is homogeneous, stable, it leaves a soft and pleasant film on the skin after rinsing.

A shampoo in all respects similar but which does not contain the complex of Example 4 gives a dry touch after rinsing

Example 8 Emulsion Formulation

Polyose ester compound of Example 4: 2.5% Polysorbate 80: 4%

Capric caprylic triglyceride: 6%

Stearic acid: 10%

Water: to complete 100%

We obtain a beautiful emulsion, homogeneous and stable. The polyose-ester compound of Example 4 is therefore emulsifying. It brings in addition a soft and substantive touch.

Example 9 Emulsion Formulation

Polyose ester compound of Example 5: 2.5% Capric caprylic triglyceride: 10% Span 60 (sorbitan stearate): 3% Water: to complete 100%

We obtain a beautiful emulsion, homogeneous and stable. The polyose-ester compound of Example 5 is therefore coemulsifier. It brings in addition a soft and substantive touch.

Claims

1. Product resulting from grafting by esterification or transesterification on at least part of the hydroxyl functions of an ulvane-type polysaccharide in acid form or in the form of a mono- or divalent salt, especially a sodium salt, of fatty chains or mixtures of fatty chains containing 8 to 28 carbon atoms, said fatty chains being saturated or unsaturated, linear or branched.

2. Product according to claim 1, characterized in that said ulvane-type polysaccharide is in the form of a mono-or divalent salt, especially a sodium salt.

3. Process for synthesizing products or mixtures containing at least one product as defined in claim 1 or 2, characterized in that it comprises a step of esterification or transesterification of at least a part of the hydroxyl functions of an ulvane-type polysaccharide or a salt thereof, obtained by extraction from an ulva or enteromorphous alga or a mixture of these algae.

4. Process according to claim 3, characterized in that it is carried out on an extract of ulva or enteromorph in solid form containing at least 85%, preferably at least 95% by weight of ulvan.

5. Method according to claim 3 or 4, characterized in that it comprises a step of esterification through an acid chloride of a fatty chain acid comprising from 8 to 28 carbon atoms.

6. Method according to one of claims 3 or 4, characterized in that it comprises a step of grafting fatty chains as defined in claim 1 by transesterification on at least a portion of the hydroxyl groups of said ulvan, from C 8 -C 28 fatty acid esters of C 1 -C 6 alcohol or mixtures of such esters.

7. The method of claim 6, characterized in that said transesterification is carried out in a solvent medium, said solvent is then removed by evaporation.

8. Process according to claim 6, characterized in that said transesterification is carried out in a non-solvent medium.

9. The method of claim 8, characterized in that a solvent is added to adjust the viscosity of the reaction medium.

10. The method of claim 8 or 9, characterized in that said transesterification is carried out in the presence of a metal soap or a mixture of metal soaps.

11. The method of claim 10, characterized in that said metal soap is then removed by neutralization with an acid.

12. Method according to one of claims 8 to 11, characterized in that it comprises a step of extraction through at least one solvent.

13. The method of claim 12, characterized in that it comprises at least one extraction step with an aqueous medium to recover at least a portion of the product resulting from said transesterification in the form of an aqueous gel.

14. The method of claim 13, characterized in that it further comprises an extraction step carried out by means of an organic solvent of the non-extracted product during extraction by said aqueous medium.

15. Use of the product as defined in claim 1 or 2 or as obtained by the method of one of claims 3 to 14 as surfactant.

16. Use according to claim 15, characterized in that said product is used as an emulsifying agent.

17. Use according to claim 15 or 16, characterized in that said product is used in a cosmetic or pharmaceutical composition for topical application as an agent conferring a soft and / or substantive feel and / or as a moisturizing agent and or as an agent conferring film-forming properties.

18. Use according to one of claims 15 or 16, characterized in that said product is used in a composition for the recovery or dispersion of hydrocarbons on the ground or on a body of water.