FR3016632A1 - PROCESS FOR TRANSFORMING POLYSACCHARIDES TO OXYGENIC MOLECULES IN THE PRESENCE OF NEUTRAL ORGANIC SUPERBASES - Google Patents

Abstract

The present invention relates to a process for transforming a feedstock comprising at least one polysaccharide chosen from starch, inulin, lignocellulosic biomass, cellulose and hemicellulose and oligosaccharides resulting from the hydrolysis of said compounds, alone or in admixture, in oxygenated molecules in which said charge is brought into contact in a solvent with a catalyst comprising at least one neutral organic superbase consisting of a carbon skeleton having no ionic bond between the atoms which constitute it and whose basicity is characterized by a pKa in acetonitrile at 25 ° C greater than 20.

Description

FIELD OF THE INVENTION The invention relates to a process for transforming a feedstock comprising at least one polysaccharide chosen from starch, inulin, lignocellulosic biomass, cellulose and hemicellulose and oligosaccharides derived from hydrolysis. said compounds, alone or as a mixture, in oxygenated molecules employing at least one neutral organic superbase. The use of this type of catalyst makes it possible to convert said polysaccharides into oxygenated molecules under mild conditions of temperature and pressure. PRIOR ART For a few years now, there has been a strong renewed interest in the incorporation of products of renewable origin into the fuel and chemical sectors, in addition to or in substitution for products of fossil origin. One possible route is the conversion of a feedstock comprising at least one polysaccharide such as, for example, starch or cellulose contained in renewable plant resources into chemical products or intermediates. The production of chemicals or fuels from polysaccharides can both reduce energy dependence on oil and preserve the environment through the reduction of greenhouse gas emissions.

The transformation of a feedstock comprising at least one polysaccharide into oxygenated molecules has been intensively studied in recent years by acidic, homogeneous or heterogeneous catalysis, as well as by enzymatic catalysis. Basic catalysis has been little studied, and systematically in the presence of ionic and / or inorganic bases.

The term ionic base includes compounds with a basic, non-neutral character, comprising an ionic bond between its constituents, such as, for example, all metal hydroxides (NaOH, CsOH, Ba (OH) 2, Mg (OH) 2), hydroxides and the like. Ammonium (NH4OH, NR4OH with R = alkyl), metal hydrides (KH, NaH, LiH), metal carbonates (CaCO3, Na2CO3, K2003), metal phosphates (K3PO4, K2HPO4, Na3PO4, Na2HPO4) metal amides (LiNH2, NaNH2, [(CH3) 2CH] 2NLi (LDA)).

The term inorganic base includes, in a broad definition, all the bases, neutral or ionic, not being constituted by carbon atoms. This definition therefore encompasses the ionic bases described above, with the exception of carbonates, tetraalkyl ammonium NR4OH and organic amides (LDA), and makes it possible to add to this list, inter alia, gaseous ammonia NH3, base inorganic nonionic. The alkaline degradation of cellobiose to glucose and fructose has been described by O. Bobleter (Monatshefte für Chemie, 1985, 116, 961-971) at temperatures between 60 and 85 ° C in sodium hydroxide solutions ranging from 01 to 0.1N. The best results are obtained for a solution of NaOH at 0.1N at 70 ° C with a total cellobiose conversion and a glucose + fructose yield of 32%. More recently, D. Esposito (ChemSusChem, 2013, 6, 989-992) studies the transformation of cellulose in water at 220 ° C in the presence of barium hydroxide Ba (OH) 2 to form lactic acid with a yield of 42%. F. Jerome has recently combined neutral organic superbases with a pKa at 25 ° C in acetonitrile greater than 20, such as for example 1,4-diazabicyclo [2.2.2] octane (DABCO), 1.8-the diazabicyclo [5.4.0] undec-7-ene (DBU), 1,5,7-Triazabicyclo [4.4.0] dec-5-ene (TBD), 1-ethyl-2,2,4,4, 4-pentakis (dimethylamino) -2? 5,4? 5-catenadi (phosphazene) (P2-Et) and 1,1,3,3-tetramethylguanidine (TMG) with carbon dioxide to solubilize microcrystalline cellulose in DMSO (ChemSusChem) 2013, 6, 593-596). The cellulose is suspended in DMSO at a level of 1 to 15% by weight and the optimum conditions for solubilization of the cellulose are identified at 40 ° C., 2 bar of CO 2 and a base / DMSO ratio of 9% by weight. The combination superbase / CO2 in DMSO is considered a "switchable solvent" to activate cellulose and therefore only used to solubilize and destructure, but does not allow its conversion into chemicals. The cellulose thus activated is then only hydrolysed by acid catalysis in the presence of 12N HCl, at 150 ° C. under microwaves (250W) for 1 hour to obtain glucose and oligosaccharides.

No example in the literature therefore describes the transformation of polysaccharides into oxygenated molecules by means of a neutral organic superbase described in the present invention.

Throughout the remainder of the text, the term "neutral organic superbase" is understood to mean molecules consisting of a carbon skeleton having no ionic bond between the atoms which constitute it and whose basicity is characterized by a pKa in acetonitrile at 25.degree. ° C greater than 20, which can be called superbasicity, according to a classification commonly accepted in the literature (Leito et al, J. Org Chem 2002, 67, 1873 and 2005, 70, 1019). SUMMARY OF THE INVENTION An object of the present invention relates to a process for transforming a feedstock comprising at least one polysaccharide chosen from starch, inulin, lignocellulosic biomass, cellulose and hemicellulose and oligosaccharides derived from hydrolyzing said compounds, alone or as a mixture, into oxygenated molecules in which said feedstock is contacted in a solvent with a catalyst comprising at least one neutral organic superbase consisting of a carbon skeleton having no ionic bond between the constituent thereof and whose basicity is characterized by a pKa in acetonitrile at 25 ° C. greater than 20. An advantage of the present invention is to provide a process for transforming a feedstock comprising at least one polysaccharide which makes it possible to obtain a mixture of products comprising monosaccharides (glucose, fructose), monosaccharide derivatives (ketones, carboxylic acids, polyols, alcohols, cools), oligosaccharides and soluble polymers. Another advantage of the present invention is to provide a selective process for converting a feedstock comprising at least one polysaccharide into molecules having a number of carbon atoms equal to 6 and in particular hexoses. The process according to the invention thus makes it possible to obtain an improved yield of hexoses compared with the processes of the prior art, and in particular at a lower temperature. Another advantage of the present invention is to provide a process for transforming a feedstock comprising at least one less corrosive polysaccharide than the processes of the prior art using ionic bases as catalysts.

DETAILED DESCRIPTION OF THE INVENTION The invention relates to a process for transforming a feedstock comprising at least one polysaccharide chosen from starch, inulin, lignocellulosic biomass, cellulose and hemicellulose and oligosaccharides derived from hydrolysis of said compounds, alone or as a mixture, into oxygenated molecules in which said feedstock is contacted in a solvent with a catalyst comprising at least one neutral organic superbase. The filler In accordance with the invention, the polysaccharide (s) constituting the filler of the process according to the invention is (are) chosen from starch, inulin, lignocellulosic biomass, cellulose, hemicellulose and oligosaccharides derived from the hydrolysis of said compounds, alone or in mixture. Starch (C6H1005) is found in large quantities in the storage organs of many plants. It is a connected polymer of glucose. Starch is insoluble in water at ambient temperature and pressure. Starch is found in the reserve organs of many plants: cereals, legumes, roots, tubers and rhizomes, and fruits. Inulin CsnHion + 205n ± i is like starch a means of storing energy for plants. It is a linear fructose polymer having a glucose end. Inulin is usually soluble in hot water. Inulin is found in plants, particularly in the roots of astaraceae. Lignocellulosic biomass consists essentially of three natural components present in varying amounts according to its origin: cellulose, hemicellulose and lignin. It is found in any plant: grass, branches, agricultural residues, trees, corn plants, etc. Cellulose (C6H1005) n represents the major part (40-60%) of the composition of lignocellulosic biomass. It is a semi-crystalline linear homopolymer of cellobiose. The cellulose is insoluble in water at ambient temperature and pressure.

Hemicellulose constitutes 20 to 40% by weight of the lignocellulosic biomass. Unlike cellulose, this polymer consists mainly of pentose monomers (5-atom rings) and hexoses (6-atom rings). Hemicellulose is an amorphous heteropolymer with a degree of polymerization lower than that of cellulose (30-100), and which is generally soluble in water. The oligosaccharides are oligomers of pentoses and / or hexoses with a degree of polymerization lower than that of cellulose and hemicellulose (2-30). They can be obtained by partial hydrolysis of starch, inulin, lignocellulosic biomass, cellulose or hemicellulose. Oligosaccharides are generally soluble in water. Cellobiose is a special case of oligosaccharides consisting of 2 glucose units linked by a glycosidic bridge [3- (1 -> 4). Cellobiose is soluble in water. Catalysts According to the invention, the catalysts used for the conversion of the feedstock comprising at least one polysaccharide according to the present invention are neutral organic superbases. Neutral organic superbase means a molecule consisting of a carbon skeleton having no ionic bond between the atoms which constitute it and whose superbasicity is characterized by a pKa in acetonitrile at 25 ° C. greater than 20. Preferably, the neutral organic superbases used as catalysts in the process according to the invention are chosen from compounds of the family of cyclic or non-cyclic amidines, cyclic or non-cyclic bisamidines, cyclic or non-cyclic guanidines, cyclic bisguanidines or non-cyclic, N-heterocyclic carbenes whose ring size is between 5 and 10 atoms, proazaphosphatrans, cyclic or non-cyclic phosphazenes, cyclic or non-cyclic bisphosphazenes, cyclic or non-cyclic guanidinophosphazenes, cyclic bisguanidinophosphazenes or non-cyclic, said compounds being substituted with groups R1 to R5 selected from hydrogen, linear or branched alkyl chains containing 1 to 20 carbon atoms, aryls substituted or not by heteroelements or linear or branched alkyl chains containing 1 to 20 carbon atoms, said substituent groups R 1 to R 5 whether they themselves may be substituted or not, the group X of said bisamidines, bisguanidines, bisphosphazenes and bisguanidinophosphazenes being chosen from linear or branched alkyl chains containing 1 to 20 carbon atoms, aryls which may or may not be substituted by heteroelements or linear alkyl chains. or branched from 1 to 20 carbon atoms and preferably naphthalene. In the case where said substituent groups R 1 to R 5 are themselves substituted, said groups may advantageously be substituted by heteroelements. The general formulas of neutral organic superbases used as catalysts in the process according to the invention are shown below.

Neutral organic superbases according to the invention R2 R1 R2 = (NNyN-R3, NN, P1 / NNsR1 R1 R1) N-Heterocyclic carbenes R3, N, R2 R4 amidines R1, R1 RR2 NN R2 R3 / X R3 bisamidines R3, N, R4 R5,% R1 R2 guanidines R1, R2 R2, R1, X'I R4, N R3 R3 bisguanidines N, R1 Proazaphosphatrans, R1 R2, N, R2 R2 R2, R2 R2 ## STR2 ## ## STR2 ## ## STR2 ## where ## STR2 ## R 1, R 4, R 4, R 4, R 4, R 4, R 4, R 4, R 4, R 4, R 4, R 4, R 2, R 2, R 2, R 2, R 2, R 2, R 2, R 2, R 2 NP = NP = N -2 P IX 2 R2 R2 NPN R / 2 N, n 2 R 2 R 2 R 2,, R 2 N R 2 R 2, R 2 NPN / R 2 R 2 N - R 2 R2 = N = P- (N = P N1) -1-, -N-, INP 'Ft N, 2 / R2 R2 R2 NP-Ni R / 2' sP --- nR2 R2-- N R 2 phosphazenes (R 2) 2 N (R 2) 2 N / (R 2) 2 N -4-, frp = NR., N (R 2) 2 N N N (R 2) 2 cyclic guanidinosphazenes bisphosphazenes N (R 2) 2 m bisphosphazenes N (R 2) 2N M (R 1 's 2) 2 (R 2) 2 N PN (R 2) 2 bisguanidinosphazenes (R 2) 2 N N (R 2) 2 m P = N X (R 2) 2 N (R 2) 2 N (R 2) 2 N N (R 2) 2 NN (R2) 2 N (R2) 2 The compo cyclic or non-cyclic amidine esters may advantageously be chosen from 1,5-diazabicyclo [4.3.0] non-5-ene (DBN), 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) . Preferably, the amidine compound is DBU.

The cyclic or noncyclic bisamidine compounds may advantageously be chosen from 2,3,4,5,8,9,10,11-octahydro-1,3a, 5a, 7a, 9a, 12-hexaazatricyclopenta [a, ef, j ] heptalene (vinamidine I) and 2,3,4,5,6,7,8,9,10,11-decahydro-1,3a, 5a, 7a, 9a, 12-hexaazatricyclopenta [a, ef, j] heptalene (vinamidine II). Preferably, the bisamidine compound is vinamidine I.

The cyclic or non-cyclic guanidine compounds may advantageously be chosen from 1,1,3,3-tetramethylguanidine (TMG), 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) and 7 -methyl-1,5,7-triazabicyclo [4.4.0] dec-5-ene (MTBD). Preferably, the guanidine compound is TBD. The cyclic or noncyclic bisguanidine compounds may advantageously be selected from 1,8-bis (tetramethylguanidino) naphthalene (TMGN), 1,8-bis (dimethylethyleneguanidino) naphthalene (DMEGN). Preferably, the bisguanidine compound is TMGN. The N-heterocyclic carbene compounds may advantageously be chosen from 1,320-dihydro-1,3-bis (2,4,6-trimethylphenyl) -2H-imidazol-2-ylidene (IMes-NHC) and 1,3-dihydro- 1,3-bis (2,4,6-triadamantyl) -2H-imidazol-2-ylidene (Adaman-NHC). Preferably, the N-heterocyclic carbene is IMes-NHC. The proazaphosphatran compounds may advantageously be chosen from 2,8,925 trimethyl-2,5,8,9-tetraaza-1-phosphabicyclo [3.3.3] undecane (Verkade superbase) and 2,8,9-triisopropyl-2,5 , 8,9-tetraaza-1-phosphabicyclo [3.3.3] undecane. Preferably, the proazaphosphatran compound is Verkade superbase.

The cyclic or non-cyclic phosphazene compounds may advantageously be chosen from 1-ethyl-2,2,4,4,4-pentakis (dimethylamino) -2Δ5,4 Δ5-catenadi (phosphazene) (P2-Et), the 1-tert -Buty 1-4,4,4-tris (dimethylamino) -2,2-bis [tris (dimethylamino) -phosphoranylidenamino] -2α5,4 Δ5-catenadi (phosphazene) (P4-tBu) and 2-tert-Butylimino-2 diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP). Preferably, the phosphazene compound is BEMP. The cyclic or noncyclic bisphosphazene compounds may advantageously be selected from 1,8-bis (hexamethyltriaminophosphazenyl) naphthalene (HMPN) and 1,8-bis (tris pyrrolidinophosphazenyl) naphthalene (TPPN). Preferably, the bisphosphazene compound is TPPN. The guanidinophosphazen compounds may advantageously be chosen from N ", N '" ", N - (phenylphosphinimylidyne) tris [N, N, N, N-tetramethyl] guanidine (PhPi-tmg) and N', N" ", N - (phenylphosphinimylidyne) tris [N, N, W, N-tetraisopropyl] -guanidine (PhPi-tg) Preferably, the guanidinophosphazene compound is (PhPi-tmg) .The bisguanidinophosphazen compounds can advantageously be chosen from N N, N, N, N, N 41.8-naphthalenediylbis (nitrilophosphoranylidyne) hexakis [N, N, W, NL tetramethyl] guanidine (P1 (tmg) -HMPN) and N ", N ' N, N, N, N - [1,8-naphthalenediylbis (nitrilophosphoranylidyne)] hexakis [N, N, W, Artetraisopropyl] guanidine (P1 (tig) -HMPN). Preferably, the bisguanidinophosphazene compound is (P1 (tmg) -HMPN). Preferred compounds used as neutral organic superbases in the present invention are shown below. Their pKa in acetonitrile at 25 ° C is indicated in parentheses. EXAMPLES (pKa in acetonitrile) DBU (24) N 'Ncel N \ N / -V- \ \ -V- / \ = / vinamidine I (31) N NLN H TBD (26) TMGN (25) N `` NEt2 ^ INtBu \ vN IMes-NHC (23) Verkade superbase (33) BEMP (28) TPPN (33) \ \ N-N / f N -N /, Ph NP = 1 \ 1 --N \ \ \ ## EQU1 ## ## STR2 ## ## STR2 ## NNNN, / N, N P - .., '.... PI \ / --- N NEP N r NNNN Salt Y \ / --- ".N .. PhPi (tmg) (24) PhPi ( The process for transforming a feedstock comprising at least one polysaccharide into oxygenated molecules according to the invention comprises the reaction in a solvent in the presence of the catalytic composition according to the invention. the invention, the process according to the invention operates in the presence of at least one solvent chosen from water, alcohols, organic solvents, ionic liquids, supercritical media and molten hydrated inorganic salts, alone or as a mixture .

Preferably, the process according to the invention operates in the presence of at least one solvent chosen from water, alcohols and organic solvents, alone or as a mixture. In the case where the solvent used is chosen from alcohols, said solvent is advantageously chosen from ethanol, methanol, isopropanol and cyclohexanol.

In the case where the solvent used is chosen from organic solvents, said solvent is advantageously chosen from dichloromethane, toluene, dimethylsulfoxide and pentane. Preferably the solvent used is water. The process according to the invention is advantageously carried out at a temperature of between 25 ° C. and 300 ° C., preferably between 30 ° C. and 200 ° C., preferably between 50 ° C. and 100 ° C. Preferably, the process according to the invention is carried out for a period of between 1 and 24 hours, preferably between 1 and 10 hours and preferably between 1 and 6 hours.

The catalyst is advantageously introduced into the reactor in an amount corresponding to a mass ratio polysaccharide (s) / catalyst of between 1 and 1000, preferably between 1 and 500, preferably between 1 and 100, very preferably between 1 and 50 and even more preferably between 1 and 25.

The feedstock comprising at least one polysaccharide is advantageously introduced into the process according to the invention in an amount corresponding to a mass ratio solvent / polysaccharide (s) of between 1 and 1000, preferably of between 1 and 500 and, preferably, between 5 and 100. The dilution ratio of the polysaccharides is advantageously between 1: 1 and 1: 1000, preferably between 1: 1 and 1: 500 and preferably between 1: 5 and 1: 100.

The products obtained and their mode of analysis After the reaction, the reaction medium is removed and analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products of the aqueous solution. The products of the reaction are soluble in water. They consist of monosaccharides and their derivatives, oligosaccharides and soluble polymers.

By monosaccharides is meant the simple sugars (hexoses, pentoses) produced by complete or partial depolymerization of the polysaccharides, in particular glucose, galactose, mannose, xylose, fructose, altrose, .... By derivatives monosaccharides denotes the products that can be obtained by dehydration, isomerization, reduction or oxidation: ketones, hexane-diones: 2,5-hexanedione, hydroxyacetone, carboxylic acids and their esters, lactones formic acid, alkyl formates, acetic acid, alkyl acetates, hexanoic acid, alkyl hexanoates, levulinic acid, alkyl levulinates, lactic acid, alkyl lactates, glutaric acid, alkyl glutarates, 3-hydroxypropanoic acid, 3-hydroxybutyrolactone, rbutyrolactone, γ-valerolactone-furans: dicarboxylic acid furan, 5- (hydroxymethyl) ) furfural, furfural ... By oligosaccha on the one hand denotes a carbohydrate having the formula (C6H1005) n, (C51-1804) n, C6n1-110n + 205n + 1 or C5n1-18n + 204n + 1 where n is an integer greater than 1, obtained by partial hydrolysis of the starch, inulin, lignocellulosic biomass, cellulose and hemicellulose, and on the other hand a so-called mixed carbohydrate having the composition (C6H1005) m (C5H804) n, (C6nil-lioni + 205m , i) (C5n1-18n + 204n ± i) where m and n are integers greater than 1.

The term "soluble polymers" denotes all the products resulting from the condensation between monosaccharides, oligosaccharides and / or monosaccharide derivatives. For polysaccharides which are not soluble in water under the reaction conditions (eg cellulose), the amount of the water-soluble reaction products (monosaccharides and derivatives, oligosaccharides, soluble polymers) is determined by TOC analysis (Carbon Organic Total) which consists of measuring carbon in solution. The amount of monosaccharides and their derivatives is determined by HPLC analyzes. The conversion is defined as the percentage solubilization of the polysaccharide in solution and is calculated according to the following equation: Conversion (%) = 100 * Csdubllisé / Cinquant in which Csolubilisé represents the amount of solubilized carbon analyzed by COT and Ciniticrl the amount of carbon at the beginning of the reaction contained in the polysaccharide. The molar yields of the products are calculated by means of HPLC analysis. The molar yields of a product i are calculated as follows: Rdt = n (i) HPLC (mol) n (i) theoretical (mol) where n (i) HPLC represents the numbers of moles determined by HPLC analysis and n (i) theoretical theoretical number of moles of the product i calculated from the amount of substrate material introduced. For substrates soluble in water under the reaction conditions (cellobiose for example), the conversion is determined by HPLC analysis and calculated according to the following equation: Conversion (%) = 100 * (11substrate) t) Isubstrago where [substrate ] corresponds to the concentration of substrate at time t and [substrate] o corresponds to the initial concentration of substrate in the reaction medium.

The examples below illustrate the invention without limiting its scope. EXAMPLES Example 1 Transformation of Cellobiose in the Presence of TBD at 50 ° C. Example 1 according to the invention relates to the conversion of cellobiose in the presence of TBD for the production of hexoses. TBD has a pKa of 26 in acetonitrile at 25 ° C. In a 100mL reactor, 50mL of water, 1.4g of cellobiose and 0.28g of TBD are introduced. The cellobiose / catalyst mass ratio is therefore 5. The solvent / cellobiose mass ratio is 35. The reactor is heated to 50 ° C. After 2 hours of reaction, the reaction medium is removed and analyzed. The reaction liquid is then analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the conversion product content of the aqueous solution.

At 2h, cellobiose conversion is 60%. The molar yields of the products analyzed by HPLC are as follows: glucose 55%, fructose 2%. Example 2 Transformation of Cellobiose in the Presence of TBD at 100 ° C. Example 2 relates to the conversion of cellobiose in the presence of TBD for the production of hexoses. In a 100mL reactor, 50mL of water, 1.4g of cellobiose and 0.26g of TBD are introduced. The reactor is heated to 100 ° C. The cellobiose / catalyst mass ratio is therefore 5. The solvent / cellobiose mass ratio is 35. After 2 hours of reaction, the reaction medium is removed and analyzed. The reaction liquid is then analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the conversion product content of the aqueous solution. At 2h, cellobiose conversion is 75%. The molar yields of the products analyzed by HPLC are the following: glucose 47%, fructose 33%. Example 3 Transformation of cellulose in the presence of TBD at 100 ° C. Example 3 according to the invention relates to the conversion of cellulose in the presence of TBD for the production of hexoses.

In a 100 ml reactor, 50 ml of water, 1.3 g of cellulose and 0.26 g of TBD are introduced. The reactor is heated to 100 ° C. The mass ratio of cellulose to catalyst is therefore 5. The weight ratio solvent / cellulose is 39. After 2 hours of reaction, the reaction medium is taken and analyzed. The reaction liquid is then analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the conversion product content of the aqueous solution. The cellulose conversion is 8%. The molar yields of the products analyzed by HPLC are the following: glucose 5%, fructose 3%.

EXAMPLE 4 Transformation of Cellobiose in the Presence of BEMP at 50 ° C. Example 4 according to the invention relates to the conversion of cellobiose in the presence of BEMP for the production of hexoses. BEMP has a pKa of 28 to 25 ° C in acetonitrile.

In a 100mL reactor, 50mL of water, 1.4g of cellobiose and 2700 of BEMP are introduced. The cellobiose / catalyst mass ratio is therefore 5. The solvent / cellobiose mass ratio is 35. The reactor is heated to 50 ° C. After 2 hours of reaction, the reaction medium is removed and analyzed. The reaction liquid is then analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the conversion product content of the aqueous solution. At 2 o'clock, the cellobiose conversion is 78%. The molar yields of the products analyzed by HPLC are as follows: glucose 72%, fructose 4%.

EXAMPLE 5 Transformation of Cellobiose in the Presence of BEMP at 100 ° C. Example 5 according to the invention relates to the conversion of cellobiose in the presence of BEMP for the production of glucose. In a 100mL reactor, 50mL of water, 1.4g of cellobiose and 2700 of BEMP are introduced. The cellobiose / catalyst mass ratio is therefore 5. The solvent / cellobiose mass ratio is 35. The reactor is heated to 100 ° C. After 2 hours of reaction, the reaction medium is removed and analyzed. The reaction liquid is then analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the conversion product content of the aqueous solution.

At 2h, cellobiose conversion is 99%. The molar yields of the products analyzed by HPLC are as follows: glucose 97%, fructose 1%.

Claims (4)

REVENDICATIONS1. Process for the transformation of a feedstock comprising at least one polysaccharide chosen from starch, inulin, lignocellulosic biomass, cellulose and hemicellulose and oligosaccharides resulting from the hydrolysis of said compounds, alone or as a mixture, into molecules oxygenates wherein said filler is contacted in a solvent with a catalyst comprising at least one neutral organic superbase consisting of a carbon skeleton having no ionic bond between the constituent atoms and whose basicity is characterized by a pKa in acetonitrile at 25 ° C greater than 20. 2. Method according to claim 1 wherein said neutral organic superbases used as catalysts are chosen from compounds of the family of cyclic or non-cyclic amidines, cyclic or non-cyclic bisamidines, cyclic or non-cyclic guanidines, cyclic or non-cyclic bisguanidines. cyclic, N-heterocyclic carbenes with a ring size of 5 to 10 atoms, proazaphosphatrans, cyclic or non-cyclic phosphazenes, cyclic or non-cyclic bisphosphazenes, cyclic or non-cyclic guanidinophosphazenes, cyclic or non-cyclic bisguanidinophosphazenes , said compounds being substituted with groups R1 to R5 chosen from hydrogen, linear or branched alkyl chains containing 1 to 20 carbon atoms, aryls optionally substituted by heteroelements or linear or branched alkyl chains comprising 1 to 20 carbon atoms, said groups substituents R1 to R5 may themselves be substituted or not, the X group of said bisamidines, bisguanidines, bisphosphazenes and bisguanidinophosphazenes being selected from linear or branched alkyl chains comprising 1 to 20 carbon atoms, aryls substituted or not by heteroelements or linear or branched alkyl chains comprising 1 to 20 carbon atoms. 3. The process as claimed in claim 2, in which the cyclic or noncyclic amidine compounds are chosen from 1,5-diazabicyclo [4.3.0] non-5-ene (DBN) and 1,8-diazabicyclo [5.4.0]. ] undec-7-ene (DBU). 4. Process according to claim 2, in which the cyclic or noncyclic bisamidine compounds are chosen from 2,3,4,5,8,9,10,11-octahydro-1,3a, 5a, 7a, 9a, 12- Hexaazatricyclopenta [a, eHheptalene (vinamidine I), 2,3,4,5,6,7,8,9,10,11-decahydro-1,3a, 5a, 7a, 9a, 12-hexaazatricyclopenta [a, efeeptalene (vinamidine II). . The process according to claim 2 wherein the cyclic or noncyclic guanidine compounds are selected from 1,1,3,3-tetramethylguanidine (TMG), 1,5,7-triazabicyclo [4.4.0] dec-5-ene ( TBD) and 7-methyl-1,5,7,7-triazabicyclo [4.4.0] dec-5-ene (MTBD). 6. The method of claim 2 wherein the cyclic or non-cyclic bisguanidine compounds are selected from 1,8-bis (tetramethylguanidino) naphthalene (TMGN), 1,8-bis (dimethylethyleneguanidino) naphthalene (DMEGN). 7. Process according to claim 2, in which the N-heterocyclic carbene compounds are chosen from 1,3-dihydro-1,3-bis (2,4,6-trimethylphenyl) -2H-imidazol-2-ylidene (IMesNHC). ), 1,3-dihydro-1,3-bis (2,4,6-triadamantyl) -2H-imidazol-2-ylidene (Adaman-NHC). The process according to claim 2 wherein the proazaphosphatran compounds are selected from 2,8,9-trimethyl-2,5,8,9-tetraaza-1-phosphabicyclo [3.3.3] undecane (Verkade superbase) and the 2,8,9-triisopropy1-2,5,8,9-tetraaza-1-phosphabicyclo [3.3.3] undecane. 9. The process as claimed in claim 2, in which the cyclic or non-cyclic phosphazene compounds are chosen from 1-ethyl-2,2,4,4,4-pentakis (dimethylamino) -2Al5,4-catenadi (phosphazene) (P2). And 1-tert-Butyl-4,4,4-tris (dimethylamino) -2,2-bis [tris (dimethylamino) -phosphoranylidenamino] -2α5,4 Δ5-catenadi (phosphazene) (P4-tBu) and 2-tert-Butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine (BEMP). 10. The method of claim 2 wherein the cyclic or non-cyclic bisphosphazen compounds are selected from 1,8-bis (hexamethyltriaminophosphazenyl) naphthalene (HMPN) and 1,8-bis (trispyrrolidinophosphazenyl) naphthalene (TPPN). 11. The process as claimed in claim 2, wherein the guanidinophosphazen compounds are chosen from AP, Af-, VH- (phenylphosphinimylidyne) tris [N, N, W, Af-tetramethyl] guanidine (PhRrtmg) and The process according to claim 2, wherein the bisguanidinophosphazen compounds are selected from IV, Nm, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N and N "N, N, N, N, N-tetramethyl-guanidine" (8-naphthalenediylbis (n itrilophosphoranylidyne)] hexakis [N, N, N-tetramethyl-guanidine] P1 (tmg) -HMPN) and N ", Ar", Ar ", e" ", e" ", Arm" "-" - [1,8-naphthalenediylbis (nitrilophosphoranylidyne)] hexakis [ N, N, W, W-tetraisopropyl] -guanidine (P1 (tig) -HMPN) 13. Process according to one of claims 1 to 12, in which the solvent is chosen from water, alcohols and organic solvents. , ionic liquids, supercritical media and molten hydrated inorganic salts, alone or in admixture 14. Process according to one of the preceding claims ns 1 to 13 wherein said process operates at a temperature between 25 ° C and 300 ° C for a period of between 1 and 24 hours. 15. Method according to one of claims 1 to 14 wherein said catalyst is introduced into the reactor in an amount corresponding to a mass ratio polysaccharide (s) / catalyst of between 1 and 1000. 16. Process according to one of claims 1 to 15 wherein said feed comprising at least one polysaccharide is introduced in an amount corresponding to a mass ratio solvent / polysaccharide (s) between 1 and 1000.