Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
  • C08B37/006—Heteroglycans, i.e. polysaccharides having more than one sugar residue in the main chain in either alternating or less regular sequence; Gellans; Succinoglycans; Arabinogalactans; Tragacanth or gum tragacanth or traganth from Astragalus; Gum Karaya from Sterculia urens; Gum Ghatti from Anogeissus latifolia; Derivatives thereof
  • C08B37/0087—Glucomannans or galactomannans; Tara or tara gum, i.e. D-mannose and D-galactose units, e.g. from Cesalpinia spinosa; Tamarind gum, i.e. D-galactose, D-glucose and D-xylose units, e.g. from Tamarindus indica; Gum Arabic, i.e. L-arabinose, L-rhamnose, D-galactose and D-glucuronic acid units, e.g. from Acacia Senegal or Acacia Seyal; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
  • C08B37/006—Heteroglycans, i.e. polysaccharides having more than one sugar residue in the main chain in either alternating or less regular sequence; Gellans; Succinoglycans; Arabinogalactans; Tragacanth or gum tragacanth or traganth from Astragalus; Gum Karaya from Sterculia urens; Gum Ghatti from Anogeissus latifolia; Derivatives thereof
  • C08B37/0087—Glucomannans or galactomannans; Tara or tara gum, i.e. D-mannose and D-galactose units, e.g. from Cesalpinia spinosa; Tamarind gum, i.e. D-galactose, D-glucose and D-xylose units, e.g. from Tamarindus indica; Gum Arabic, i.e. L-arabinose, L-rhamnose, D-galactose and D-glucuronic acid units, e.g. from Acacia Senegal or Acacia Seyal; Derivatives thereof
  • C08B37/0093—Locust bean gum, i.e. carob bean gum, with (beta-1,4)-D-mannose units in the main chain branched with D-galactose units in (alpha-1,6), e.g. from the seeds of carob tree or Ceratonia siliqua; Derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08B—POLYSACCHARIDES; DERIVATIVES THEREOF
  • C08B37/00—Preparation of polysaccharides not provided for in groups C08B1/00 - C08B35/00; Derivatives thereof
  • C08B37/006—Heteroglycans, i.e. polysaccharides having more than one sugar residue in the main chain in either alternating or less regular sequence; Gellans; Succinoglycans; Arabinogalactans; Tragacanth or gum tragacanth or traganth from Astragalus; Gum Karaya from Sterculia urens; Gum Ghatti from Anogeissus latifolia; Derivatives thereof
  • C08B37/0087—Glucomannans or galactomannans; Tara or tara gum, i.e. D-mannose and D-galactose units, e.g. from Cesalpinia spinosa; Tamarind gum, i.e. D-galactose, D-glucose and D-xylose units, e.g. from Tamarindus indica; Gum Arabic, i.e. L-arabinose, L-rhamnose, D-galactose and D-glucuronic acid units, e.g. from Acacia Senegal or Acacia Seyal; Derivatives thereof
  • C08B37/0096—Guar, guar gum, guar flour, guaran, i.e. (beta-1,4) linked D-mannose units in the main chain branched with D-galactose units in (alpha-1,6), e.g. from Cyamopsis Tetragonolobus; Derivatives thereof

Definitions

• the subject of the present invention is a process for the preparation of oligomers of at least one galactomanan under the effect of temperature and pressure. It also relates to the oligomers obtained or capable of being obtained by this process, as well as their uses.
• the invention further relates to the compositions based on the above oligomers.
• Galactomannans are nonionic polysaccharides extracted from the albumen of legume seeds of which they constitute the reserve carbohydrate. They are especially known and used as a texture agent and in particular for their viscosifying, thickening, stabilizing, water-retaining, and film-forming properties. Among the most widely used are guar gum, locust bean gum, and tara gum.
• the different galactomannans are distinguished by the proportion of D-mannopyranose and D-galactopyranose units which are represented by their mannose / galactose ratio (hereinafter M / G). Although variable from one species to another, the mannose / galactose ratio is about 1 for fenugreek, 2 for guar, 3 for tara, and 4 for locust bean.
• polysaccharides are all the more advantageous because, by their nature, they are compatible with other compounds and therefore can be used in combination with these to produce synergistic effects, inter alia, in terms of texture.
• locust bean gum in combination with xanthan gum can lead to gels of different strengths and more or less elastic consistencies.
• Native galactomannans are highly hydrophilic polymers which, at low concentrations, lead to very viscous solutions. Depending on the intended application, this aspect may limit their use.
• the properties of galactomannans can be linked to their molecular mass.
• galactomannans whose texturing properties and in particular the thickening or viscosifying property can be adjusted.
• the classic access routes to galactomannes of different molecular weights are:
• EP 0130946 for the oxidative depolymerization process in the presence of alkali, and for the basic route in the presence of oxygen,
• the enzymatic depolymerization which has the advantage of allowing a selective cleavage of the galactomananne (compared to the chemical process) is a process which is not economically advantageous. In addition, in certain cases, it is difficult to deactivate the enzyme at the end of the reaction without degrading the depoiymerized product.
• the object of the present invention is to overcome the drawbacks mentioned above by proposing a process for the preparation of galactomannan oligomers which is simple and economical to use and in which the resulting oligomers are devoid of secondary products.
• Another object of the present invention is to provide a process which allows access to a wider range of galactomannan oligomers, that is to say ranges of molecular weights which cannot be reached by conventional routes .
• a solvent system comprising: at least one solvent and optionally at least one co-solvent, and
• a subject of the invention is also the galactomannan oligomers obtained or capable of being obtained by the above-mentioned process.
• the present invention therefore relates to a process for the preparation of oligomers of at least one galactomanan, characterized in that a mixture is subjected comprising:
• a solvent system comprising at least one solvent and optionally at least one co-solvent, and - at least one oxidizing agent, at a temperature of at most 250 ° C. and a pressure of between 0.2 and 30 MPa.
• oligomer of galactomannans means galactomannans whose molecular weight by weight is less than approximately 2.5 ⁇ 10 e g / mole.
• the term "oligomer” of galactomannans more particularly designates galactomannans whose molecular weight by weight is advantageously less than 1, 5.10 e g / mole, preferably less than 600,000 g / mole, more particularly between 2000 and 50,000 g / mole .
• the molecular weight by weight of the oligomers is between 2000 and 10 OOOg / mole.
• the molecular weight by weight can be measured by size exclusion chromatography (SEC).
• the galactomannans can be used alone or as a mixture.
• the galcatomannans non-limiting mention may be made of galactomannans having a mannose / galactose ratio (M / G) of at most 5, and more particularly guar, carob, cassia and tara.
• M / G mannose / galactose ratio
• the galactomannan is guar.
• the galactomannan is advantageously in the form of a powder.
• the powder is obtained by conventional grinding means such as grinding in mills of the type: - cylinder mills for powder of medium particle size type 100 mesh, that is to say a flour having at most 1% by mass of particles greater than 80 mesh and at most 10% by mass of particles less than 200 mesh; - pin mills for finer particle size powder:
• ° mesh type 200 that is to say a powder having no particles greater than 80 mesh and having at most 60% by mass of particles less than 200 mesh
• ⁇ mesh type 175 that is to say a powder having at most 1% by mass of particles greater than 80 mesh and at most 75% by mass of particles less than 200 mesh.
• the powder can be used as it is or after treatment with suitable enzymes such as, for example, alkaline, acidic and / or neutral proteases; lipases; phytases; alkaline, acidic and / or neutral phosphatases; amylases.
• the treatment with enzymes is carried out by conventional and known methods.
• the particle size of said powder can fluctuate between 10 and 150 microns. In the case of treated powders, this particle size is more particularly from 20 to 60 microns, preferably from 30 to 50 microns.
• Granulometry measurements can be carried out by the laser granulometry technique, using a MALVERN granulometer, sold by the company Malvern Instruments S.A.
• the mixture comprises a solvent system comprising at least one solvent and optionally at least one co-solvent.
• the solvent can be chosen from carbon dioxide, water, ammonia, C 1 -C 5 alkanes, C 1 and C 2 fluoroalkykes, alone or in mixtures.
• alkanes C-
• the solvent system comprises a co-solvent
• the latter is advantageously chosen from protic solvents, and more particularly from C C alcohols, C C ketones. Mention may be made, for example, of ethanol as alcohol and acetone as ketone.
• the depolymerization of galactomannans into galactomanan oligomers requires the presence of at least one oxidizing agent.
• This agent can be selected from air, O 2 , hydrogen peroxide, nitric acid, and mixtures thereof.
• the above-mentioned mixture is then subjected to temperature and pressure conditions such that the galactomannan undergoes no degradation and only depolymerization.
• the temperature is advantageously between 20 and 250 ° C., preferably between 40 and 150 ° C.
• the pressure is more particularly between 2 and 25 MPa, preferably between 5 and 20 MPa.
• the starting galactomanan and the galactommannan oligomer (s) obtained have substantially the same M / G ratio.
• the choice of the solvent system as well as of the oxidizing agent is made in such a way that before the reaction they are presented either in liquid form or in gas form, and that during the reaction under the effect of temperature and pressure, they preferably pass to the state of monophasic fluid.
• the process can thus be considered as a process for depolymerization of galactomannans in the solid state by an oxidizing agent and a solvent system in the fluid state.
• the weight ratio of galactomannan (s) / solvent system is from 0.01 to 100, preferably from approximately 0.1 to 10, more particularly from 1 to 5.
• the solvent system can comprise at least one solvent and optionally at least one co-solvent.
• the weight ratio of solvent (s) / co-solvent (s) is between 99/1 and 70/30, advantageously 95/5 and 85/15 , preferably around 90/10.
• This ratio is more particularly between 0.1 and 5.10 3 , and preferably between 0.1 and 2.5.10 " 2 .
• the reaction time is variable and will of course depend on the desired molecular weight and the operating conditions, in particular the temperature of the reaction and the amount of the oxidizing agent. In general, it varies between 1 minute and 2 hours.
• the reaction medium is decompressed so as to remove the solvent, optionally the co-solvent, and the oxidizing agent.
• the oligomer is then recovered in solid form. Subsequently, the oligomer can undergo a drying step.
• the process of the invention can be carried out batchwise, semi-continuous, or even continuous. In the preferred embodiments of the invention, the process is carried out batchwise or semi-continuously.
• the process of the invention can be carried out in any type of reactor making it possible to carry out processes in a heterogeneous medium, in particular solid / fluid, and to reach the necessary temperatures and pressures.
• the reactor can be made of stainless steel or other materials. It can be arranged horizontally or vertically.
• the procedure is preferably as follows: the reactants are first introduced into the reactor; the solvent system is then introduced into the mixture of reagents causing the pressure inside the reactor to rise; the reactor is then brought to the desired temperature by supplying heat, for example by circulating a heat transfer fluid. The temperature and the pressure are kept constant for a time which is determined as a function of the mass of the oligomer which it is desired to obtain.
• the reactor is first loaded with galactomannan (s); - The reactor is then brought to the desired temperature by providing heat, for example by circulation of a heat transfer fluid; the mixture of oxidizing agent (s) and solvent system is compressed and introduced under continuous pressure into the reactor maintained at the desired pressure, for example using a high-pressure volumetric liquid pump which allows to regulate the flow of the mixture.
• the temperature, the pressure and the flow rate are kept constant until the desired oligomer is obtained.
• the reactor is continuously loaded with galactomannan, using a suitable system such as, for example, an extruder type worm system; the reactor is brought to the desired temperature by supplying heat, for example by circulation of a heat transfer fluid; the mixture of oxidizing agent (s) and solvent system is then compressed and introduced, under pressure, continuously into the reactor which is itself maintained at the desired pressure, for example using a high pressure volumetric liquid pump which regulates the flow of the mixture.
• the temperature, the pressure and the flow rate are kept constant until the desired oligomer is obtained.
• the present invention also relates to the galactomannan oligomers obtained or capable of being obtained by the process according to the invention. More particularly, this process provides access to a range of galactomanan oligomers not yet obtained by known processes of depolymerization, that is to say molecular weights between 2000 and 10 000 g / mole.
• This process also makes it possible to obtain oligomers of galactomannans according to the invention, which have galacturonic and / or mannuronic groups, when the oxidizing agent used is hydrogen peroxide.
• the galactomanan oligomers according to the invention have good gelling and / or emulsifying properties, while having a low critical miscellar concentration.
• the invention also extends to the uses of the galactomannan oligomers obtained or capable of being obtained by the process of the invention, in the cosmetic, dyeing, food, detergency, agrochemical, industrial formulations, pharmaceutical, construction, drilling fluids.
• the subject of the invention is the compositions based on galactomannan oligomers obtained or capable of being obtained by the process of the invention, in the fields of cosmetics, dyes, food, detergency, agrochemistry, those of industrial formulations, pharmaceutical, building materials, drilling fluids.
• the galactomannan oligomers obtained are characterized according to two techniques: size exclusion chromatography (SEC) to obtain the molecular weight by weight;
• the analyzes were carried out using a SEC device comprising an injection system (Waters 515 + Wisp +), two chromatographic columns (Shodex SB 806HQ 30 cm 5 ⁇ m and Asahi GFA 30 60 cm 5 ⁇ m) and two systems detection (RI Waters 410 refractometer and MALLS Wyatt laser He 633 nm light scattering).
• the elution solvent is Millipore 18 M ⁇ water at pH 9-10 containing 0.1 M LiCl and 200 ppm NaN 3 .
• the solvent flow rate is 0.8 ml / min.
• the solution injected (100 ⁇ l) contains approximately 1% of product and the molecular weight by weight is established by MALLS without calibration. Indeed, the scattered light extrapolated at zero angle is proportional to C x M x (dn / dc) 2 : - C corresponds to the concentration of the oligomer,
• M corresponds to the molecular mass by weight, and the ratio (dn / dc) is here equal to 0.140.
• a 50 cc reactor operating discontinuously, is loaded with:
• a guar with a molecular mass by weight of 100,000 g / mol is recovered.
• a 50 cc reactor operating semi-continuously, is loaded with 2.5 g of a guar of molar mass 2, 5.10 e g / mole.
• the assembly is compressed to 20 MPa by injection of CO 2 under pressure.
• 20 cc of an oxidant mixture H 2 ⁇ 2 / H 2 O / C 2 H 5 OH at 5.10 "3 mol / l H 2 O 2 ) is injected into the reactor with CO 2 in a ratio of CO 2 / oxidant weight equal to 90/10
• the whole is brought to 20 MPa by injection of CO 2 under pressure at 50 ° C.
• the residual H 2 O 2 / H 2 ⁇ / C 2 H 5 OH mixture is extracted by sweeping with CO 2 .
• a guar with a molecular mass by weight of 92,000 g / mol is recovered.
• a 50 cc reactor operating semi-continuously, is loaded with 2.5 g of a guar of molar mass 2, 5.10 e g / mole.
• the assembly is compressed to 20 MPa by injection of CO 2 under pressure.
• 20 cc of an oxidant mixture H 2 O 2 / H 2 O / C 2 H 5 OH at 5.10 "2 mol / l of H 2 O 2 ) is injected into the reactor with CO 2 in a ratio of CO 2 / oxidant weight equal to 90/10
• the whole is brought to 20 MPa by injection of CO 2 under pressure at 50 ° C.
• the residual H 2 ⁇ 2 / H 2 O / C 2 H 5 OH mixture is extracted by sweeping with CO 2 .
• a guar with a molecular mass by weight of 6000 g / mol is recovered.
• a 50 cc reactor operating semi-continuously, is loaded with 2.5 g of a guar of molar mass 2, 5.10 e g / mole.
• the assembly is compressed to 819 Pa by injection of CO 2 under pressure.
• 20 cc of an oxidant mixture H 2 O 2 / H 2 O / C 2 H 5 OH at 5.10 "2 mol / l of H 2 O 2 ) is injected into the reactor with CO 2 in a ratio of CO 2 / oxidant weight equal to The whole is brought to 20 MPa by injection of CO 2 under pressure at 50 ° C.
• the residual H 2 O 2 / H 2 O / C- 2 H 5 OH mixture is extracted by sweeping with CO 2 .
• a guar with a molecular mass by weight of 10,000 g / mol is recovered.
• Example 5 Process for the preparation of guar oligomer A 50 cc reactor, operating batchwise, is loaded with:
• the residual H 2 O 2 / H 2 ⁇ / C 2 H 5 O_-l mixture is extracted by sweeping with CO 2 .
• a guar with a molecular mass by weight of 725,000 g / mol is recovered.

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• 1999
  • 1999-12-27 FR FR9916542A patent/FR2802932A1/fr not_active Withdrawn
• 2000
  • 2000-12-27 EP EP00993620A patent/EP1252195A1/de not_active Withdrawn
  • 2000-12-27 AU AU28602/01A patent/AU2860201A/en not_active Abandoned
  • 2000-12-27 WO PCT/FR2000/003696 patent/WO2001048023A1/fr not_active Application Discontinuation

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