WO2015158634A1 - Method for converting a feedstock including lignocellulosic biomass, using a homogeneous catalyst including a lanthanide in combination with a heterogeneous catalyst - Google Patents

Abstract

The invention relates to a method for converting a feedstock selected from lignocellulosic biomass and carbohydrates, individually or as a mixture, into mono-oxygenated or poly-oxygenated compounds, in which the feedstock is simultaneously treated with a catalytic system including a combination of one or more homogeneous catalysts selected from the metal salts in which the metal M is a lanthanide selected from: Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and one or more heterogeneous catalysts, in a single reaction chamber, in the presence of at least one solvent, said solvent being water only or water in a mixture with at least one other solvent, in a reducing atmosphere and at a temperature of 50 °C to 300 °C and at a pressure of 0.5 MPa to 20 MPa.

Description

 METHOD FOR TRANSFORMING A LOAD COMPRISING A

LIGNOCELLULOSIC BIOMASS USING A HOMOGENEOUS CATALYST COMPRISING A LANTHANIDE IN COMBINATION WITH A CATALYST

HETEROGENE PRIOR ART

In recent years, there has been a strong revival of interest in incorporating renewable products into the fuel and chemical sectors, in addition to or in substitution for products of fossil origin. One possible route is the conversion of the cellulose contained in the lignocellulosic biomass into products or chemical intermediates, such as products containing from one to six hydroxyl functions, namely n-propanol, ethylene glycol, propylene glycol, glycerol, 1, 2-butanediol or 1, 2-hexanediol. The term lignocellulosic biomass (LBC) or lignocellulose encompasses several constituents present in varying amounts depending on its origin: cellulose, hemicellulose and lignin. Hemicellulose and cellulose constitute the carbohydrate part of lignocellulose. They are polymers of sugars (pentoses and hexoses). Lignin is a macromolecule rich in phenolic motifs. By lignocellulosic biomass. for example, products derived from logging and agricultural by-products such as straw, as well as certain crops with a high agricultural yield such as miscanthus or poplar.

The production of chemicals from lignocellulosic biomass can both reduce energy dependence on oil and preserve the environment by reducing greenhouse gas emissions without using resources for food uses.

The direct transformation of a charge selected from lignocellulosic biomass and carbohydrates, alone or in mixture, into chemical products or intermediates, especially mono- or polyoxygenated. is a particularly interesting way. By direct transformation, we mean the transformation into a step of said charge, possibly pretreated, to mono- or polyoxygenated products.

The valorization of lignocellulosic biomass or of the cellulose contained in the biomass by the use of a combination of homogeneous and heterogeneous catalysts is widely described in the literature.

 In particular, the use of a combination of homogeneous catalysts based on Bronsted acids and heterogeneous catalysts has often been described for the transformation of lignocellulosic biomass or cellulose.

The patent application WO2013 / 015990 describes a process for producing polyols and in particular alcohols, organic acids, aldehydes, monosaccharides, polysaccharides, phenolic compounds, carbohydrates, glycerol, proteins and depolymerized lignin as well as in hydrocarbons by the hydrolysis and hydrogenation of microcrystalline celluloses, pulp and glucose, in the presence of a catalyst system comprising an unsupported compound based on tungsten or molybdenum, alone or as a mixture, and a supported compound based on Pt, Pd, Ru, Rh, Ni, Ir alone or in admixture on a solid support selected from carbon, Al ₂ O ₃ , ZrO ₂ , SiO ₂ , MgO, Ce _x Zr _y O ₂ , TiO ₂ , SIC, silica alumina, clays, zeolites taken alone or as a mixture. The unsupported compounds based on tungsten or molybdenum, alone or as a mixture, are the Bronsted acids chosen from tungstic acid, molybdic acid, ammonium metatungstate, tungsten, molybdenum and tungstic acid heteropolyanions. of molybdic acid, alone or in admixture. Said process allows the conversion of cellulose to ethylene glycol or propylene glycol with high yield and good selectivity. In the examples illustrating the invention, the unsupported catalysts are the following Bronsted acids: tungstic acid (WO ₃ .xH ₂ O), phosphotungstic acid (H ₃ PW ₁₂ 0 ₄ o) and ammonium metatungstate ( (ΝΗ ₄ ) ₆ (νν ₁₂ θ ₄ ο) .χΗ ₂ 0). The supported catalyst is Ni / Norit CA-1 or Pd / C, the metal contents being between 0.6 and 5% by weight. The majority products in these examples are ethylene glycol and propylene glycol. Cellulose transformation is carried out in water at a content of 1 wt% cellulose / water to ^245th C under 60 bar of H ₂ (at ambient temperature). US2009 / 0326286 discloses the hydrolysis and hydrogenation of lignocellulosic biomasses to monosaccharides in the presence of a homogeneous catalyst and a heterogeneous catalyst. The homogeneous catalyst is described as a mineral or organic Bronsted acid preferably selected from H ₂ SO ₄ , H ₃ PO ₄ acids. H ₃ PO ₃ , H ₃ PO ₂ and CH ₃ COOH. The heterogeneous catalyst is based on activated charcoal or acidic alumina on which is deposited a transition metal selected from ruthenium, nickel, platinum and palladium at contents of between 0.1% and 5.5% by weight. relative to the total mass of heterogeneous catalyst. The products formed and the associated yields are not specified.

Sels et al. (Chem Commun 2010, 46, 3577-3579) study the transformation of cellulose into hexitols (sorbitol + mannitol) in the presence of a homogeneous catalyst and a heterogeneous catalyst. The homogeneous acidic catalysts used are Bronsted acids H ₂ S0 ₄ and H ₄ SiW ₁₂ O40. The heterogeneous catalyst is 5% Ru / C weight. The conversion of the microcrystalline cellulose is respectively 50% and 80% with these two acids for a reaction in water at 190X and at 50 bars of H ₂ for 24 h (pH (25 _° C. ₎ -2). The associated yields of hexitols are 13% and 48%. The ground cellulose is solubilized more rapidly with a total conversion in 1 hour under the same operating conditions and an 87% hexitol yield.

With a slightly different perspective, Zhang et al. (Chem., 2012, 48, 7052-7054) combine tungstic acid H ₂ WO ₄ , not soluble in water at room temperature, and heterogeneous catalyst 5% Ru / C weight for cellulose conversion. ethylene glycol in water at 245 ° C at 60 bar H ₂ . The peculiarity of this system is that the tungstic acid solubilizes hot and goes from the heterogeneous to the homogeneous during the rise in temperature to 245 ° C. The ethylene glycol yield reached 59% with total conversion of the cellulose in 30 minutes.

More recently. C. Liang (Green Chem, 2013, 15, 891-895) describes a combination of catalysts for the production of ethylene glycol from cellulose in water at 245 ° C at 60 bar H ₂ . The addition of calcium hydroxide Ca (OH) ₂ in combination with the heterogeneous catalyst CuCr makes it possible to increase the yield of ethylene glycol of the reaction from 5% to 30%. The yield of propylene glycol remains stable around 30-35%. The US201 1/0060148 patent application of BIOeCON International Holding describes a process for converting lignocellulosic biomass into polyols which makes it possible to obtain a high yield of polyols and to minimize the formation of by-products. In particular, the process comprises a step of hydrolysis of cellulose and lignocellulosic biomasses to glucose, a step of hydrogenation of glucose formed into sorbitol, a step of dehydration of the polyols obtained and a recovery step, said steps being carried out in a hydrated metal salt used as a solvent in a ratio of hydrated metal salt / lignocellulosic biomass of between 1 and 50, which corresponds to a lignocellulosic bloom ratio / metal salt of between 0.02 and 1. The hydrolysis of the cellulose is carried out in a hydrated metal salt, used as a solvent, chosen from zinc, calcium and lithium halides, alone or as a mixture and in particular in ZnCl ₂ .4H ₂ O used as a solvent. The hydrolysis step is also carried out in the presence of an inorganic acid, preferably hydrochloric acid (HCl). The hydrogenation of glucose is also carried out in said hydrated metal salt, used as a solvent, in the presence of an inorganic acid, preferably hydrochloric acid (HCl) and a heterogeneous catalyst chosen from conventional hydrogenation catalysts. sugars such as Ru / C catalysts, Raney nickel, Raney copper, and nickel supported on carbon or alumina and preferably in the presence of Ru / C. without precision of the mass content of metals. The examples illustrate the use as a solvent of the hydrated inorganic salt ZnCl ₂ .4H ₂ O in a weight ratio ZnCl ₂ .4H ₂ O / cellulose of 12/1. The maximum conversion of the cellulose thus obtained after 1 h 30 is 100%.

Finally, in 2009, R. Raines (JACS, 2009. 31, 1979-1985) described the transformation of sugars, cellulose and lignocellulose into 2,5-dimethylfuran in two steps. The first step is carried out in an ionic liquid medium based on dimethylacetamide-LiCl / [EMIM] CI ([EMIM] [CI] = 1-ethyl-3-methylimidazolium chloride) at 140 ° C. for 2 hours and is catalyzed by a mixture of the metal salt of chromium trichloride (CrCl ₃ ) and hydrochloric acid (HCl) both at 10 mol% relative to the cellulose. At the end of this first step, a purification step by size exclusion chromatography is carried out and allows to eliminate the chloride ions of the medium so as to avoid ^poisoning of the catalyst used in the second step. The second step can thus take place and involves the transformation of the purified solution in the presence of a copper-based catalyst deposited on Ru / C under hydrogen, in 1-butanol at 220 ° C. for 10 hours to form 2.5- dimethylfuran. The two-step process thus described makes it possible to obtain a high selectivity for 2,5-dimethylfuran but also leads to the production of a significant quantity of humins.

It is not described in the literature method that allows a direct conversion ^of a filler selected from ia lignocellulosic biomass and carbohydrates, alone or in mixture, or mono valorisabies poiyoxygénés products. by contacting said feedstock simultaneously within the same reaction medium with a combination of at least one homogeneous catalyst selected from metal salts wherein the metal M is selected from the lanthanide, with ^the exception of ^element La, and one or more heterogeneous catalysts of the type described in the present invention.

The work of the applicant has made it possible to demonstrate that, surprisingly, the contacting of a filler chosen from lignocellulosic biomass and carbohydrates, alone or as a mixture, simultaneously, with at least one homogeneous catalyst chosen from metal salts wherein the metal M is selected from the lanthanide with ^the exception of ^the element La, and one or more heterogeneous catalysts in the same vessel réactionnelie operating in specific operating conditions makes it possible to directly obtain valorisabies mono products or polyoxygenated and reduce the content of non-valuable products, such as humins.

SUMMARY OF THE INVENTION

An object of the present invention is therefore to provide ^a load transformation method selected from lignocellulosic biomass and carbohydrates, alone or in mixture, mono- or poiyoxygénés compounds, wherein said charge is contacted, simultaneously, with a combination of one or more homogeneous catalyst (s) and one or more heterogeneous catalysts, in the same reaction chamber. in the presence of at least one solvent, said solvent being water alone or in admixture with at least one other solvent, under an atmosphere reducing agent, and at a temperature between 50 ° C and 300 ° C, and at a pressure between 0.5 MPa and 20 MPa, wherein,

said at least one homogeneous catalyst (s) being chosen from hydrated or non-hydrated metal salts having the general formula MmX _n '_n' H ₂ 0 in which the metal M is a lanthanide chosen from Ce, Pr, Nd, Pm, Sm, Eu, Gd. Tb, Dy, Ho, Er, Tm, Yb and Lu, m is an integer from 1 to 10, n is an integer from 1 to 10 and n 'is a number from 0 to 20 and X is from at least one anion chosen from halides, nitrates, carboxylates, halocarboxylates, acetylacetonates, hydroxides, alkoxides, phenolates, substituted or unsubstituted, sulphates, alkyl sulphates, phosphates, alkyl phosphates, halosulphonates, alkyl sulphonates perhaloalkylsulfonates. bis (perhaloalkylsulfonyl) amides, arenesulfonates, substituted or unsubstituted by halogen or haloalkyl groups, said anions X being identical or different in the case where n is greater than 1,

 said at least one heterogeneous catalyst (s) comprising at least one metal selected from metals of groups 6 to 11 and metals of group 14 of the periodic table and a support selected from oxides of elements selected from aluminum , titanium, silicon, zirconium, cerium and niobium, alone or as a mixture, and mixed oxides chosen from zinc, copper and cobalt aiuminates, said oxides possibly being doped with at least one metal compound chosen from tungsten, tin, molybdenum and antimony, taken alone or as a mixture, crystallized aluminosilicates or not, aluminophosphates and amorphous or crystallized carbon compounds.

In the present invention, reference is made to the new notation of the Periodic Table of Elements: Handbook of Chemistry and Physics, 76th Edition, 1995-1996.

In the present invention, the term "homogeneous catalyst" means a catalyst that is soluble in the operating conditions of the reaction. By heterogeneous catalyst is meant a catalyst that is not soluble in the reaction operating conditions. An advantage of the present invention is that it allows the direct production of mono- or polyoxygenated valorizable products while limiting the formation of non-valuable products such as solubic and insoluble humins, ie products of high molecular weight resulting from unwanted condensation of sugars and their derivatives.

In the case where the treated filler is a solid filler, that is to say preferably chosen from lignocellulosic biomass or cellulose, another advantage of the present invention is that it allows both the increase of the maximum conversion and acceleration of the kinetics of conversion of lignocellulosic biomass or of cellulose by the simultaneous use in the same reaction chamber operating under a reducing atmosphere, of the combination of at least one homogeneous catalyst and one or more heterogeneous catalyst (s) as claimed.

Another advantage of the present invention is to allow ^to obtain ^a product mixture comprising at least one of ethylene glycol and propylene glycol, with a weight ratio ethylene glycol / propylene glycol less than 8. DETAILED DESCRIPTION OF THE INVENTION The charge

 The filler treated in the process according to the invention is a filler chosen from lignocellulosic biomass and carbohydrates, alone or as a mixture, the carbohydrates being preferably chosen from polysaccharides, oligosaccharides and monosaccharides. alone or in mixture.

By polysaccharides we mean one or more compounds containing at least 10 covalently linked oste subunits. Preferred polysaccharides used as filler in the present invention are selected from starch, inulin, cellulose and hemicellulose alone or in admixture.

By oligosaccharides we mean one or more compounds containing from two to ten subunits of covalently linked osteos. By oligosaccharide, is meant more particularly, on the one hand a carbohydrate having the formula (C ₆ H ₁₀ O ₅ ) _n or C _6n H ₁₀ n ₊ 2 O _{5 n + 1} where n is an integer greater than 1, obtained by hydrolysis partial starch, inulin, lignoceliulosique biomass, cellulose ^and hémicelluiose, and secondly a carbohydrate said joint having a composition of (C ₆ H ₁₀ O 5) _m (C ₅ H ₈ O 4) _{not !} (C 6 H _{10 m} m ₊ 2O _{5m + 1)} (C _5n H _8r, O4n _{2 +} i) where m and n are integers greater than or equal to 1.

The oligosaccharides are preferably chosen from 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.

Preferred oligosaccharides used as a filler in the present invention are selected from sucrose, lactose, maltose, ^{isomaltose, the} inulobiose, melibiose, gentiobiose, trehalose, cellobiose, cellotriose, the cellotetraose and oligosaccharides from the hydrolysis of the polysaccharides named in the previous paragraph. By monosaccharides is meant simple sugars (hexoses, pentoses) which can be produced by complete or partial depolymerization of the polysaccharides.

Preferred monosaccharides used as filler in the present invention are selected from glucose, galactose, mannose, fructose, altrose. Lignocellulosic biomass consists essentially of three natural constituents present in varying amounts according to its origin: cellulose, hemicellulose and lignin.

Cellulose (C ₆ H ₁₀ O ₅ ) _n represents the major part (40-60%) of the composition of lignocellulosic biomass. Cellulose is a linear homopolymer composed of numerous units of D-Anhydroglucopyranose (AGU) linked together by β- (1 → 4) glycosidic bonds. The repetition pattern is the cellobiose dimer.

Cellulose is insoluble in water at ambient temperature and pressure.

The cellulose used may be crystalline or amorphous. Hemicellulose is the second carbohydrate in quantity after cellulose and constitutes 20 to 40% by weight of 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).

Lignin is an amorphous macromolecule present in lignocellulosic compounds in variable proportions depending on the origin of the material (straw ~ 15%, wood: 20-26%). Its function is the mechanical reinforcement, the hydrophobization and the support of the plants. This macromolecule rich in phenolic units can be described as resulting from the combination of three monomer units of propyl-methoxy-phenol type. Its molar mass varies from 5000 g / mol to 10000 g / mol for hardwoods and reaches 20000 g / mol for softwoods.

The lignocellulosic raw material may advantageously consist of wood or vegetable waste. Other non-limiting examples of lignocellulosic biomass material are farm residues such as, for example, straw, grasses, stems, cores, or shells, logging residues such as thinning products , bark, sawdust, chips, or falls, logging products, dedicated crops (short rotation coppice), residues from the agri-food industry such as residues from the cotton industry , bamboo, sisal, banana, maize, panicum virgatum, alfalfa, coconut, or bagasse, household organic waste, wood processing waste and wood used construction, pulp, paper, recycled or not.

The lignocellulosic biomass can advantageously be used in its raw form, that is to say in its entirety of these three constituents cellulose, hemicellulose and lignin. The raw biomass is generally in the form of fibrous residues or powder. It can also advantageously be milled or shredded to allow its transport. The lignocellulosic biomass feed may advantageously also be used in its pretreated form, that is to say in a form containing at least one cellulosic part after extraction of lignin and / or hemicellulose. The biomass is preferably pretreated to increase the reactivity and accessibility of the cellulose within the biomass prior to processing. These pretreatments are of a mechanical, thermochemical, thermomechanical and / or biochemical nature and cause the decystallinization of the cellulose, a decrease in the degree of polymerization of the cellulose, the solubilization of the hemicellulose and / or lignin and / or or cellulose or partial hydrolysis of hemicellulose and / or cellulose following treatment.

Pretreatment prepares the lignocellulosic biomass by separating the carbohydrate portion of the lignin and adjusting the size of the biomass particles to be treated. The size of the biomass particles after pretreatment is generally less than 5 mm, preferably less than 500 microns.

Catalysts

 According to the invention, said feedstock is brought into contact in the process according to the invention, simultaneously with one of one or more homogeneous catalyst (s) and one or more heterogeneous catalyst (s). ) as claimed, in the same reaction chamber, in the presence of at least one solvent, said solvent being water alone or in admixture with at least one other solvent, under a reducing atmosphere, and at a temperature of between 50 ° C. C and 300 ° C, and at a pressure of between 0.5 MPa and 20 MPa.

An essential criterion of the present invention lies in bringing said charge into contact under the operating conditions as claimed simultaneously with a combination of one or more homogeneous catalyst (s) and one or more catalyst (s). s) heterogeneous (s) as claimed, within the same reaction chamber.

Indeed, the reactions involved in the process for transforming said feedstock are not successive reactions because of the use and operation simultaneously a combination of one or more homogeneous catalyst (s) as claimed and one or more heterogeneous catalysts in the same reaction chamber. The conversion of the feedstock induced by the homogeneous catalyst (s) and the transformation of the products thus dissolved by the heterogeneous catalyst (s) is therefore concomitant and complementary. H is possible to take advantage of this compatibility between homogeneous and heterogeneous catalysts to ^release itself from any intermediate processing work or purification, synonyms additional process costs and significant material losses associated with this step.

Preferably, said method according to the invention does not operate in two successive steps. According to the invention, the at least one homogeneous catalyst (s) is (are) chosen from hydrated or non-hydrated metal salts having the general formula M _m X _n .n'H ₂ 0 wherein metal M is a lanthanide selected from Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, m is an integer from 1 to 10, n is an integer between 1 and 10 and n 'is a number between 0 and 20 and X is at least one anion selected from halides, nitrates, carboxylates, halocarboxylates, acetylacetonates, alcoholates, phenolates, substituted or unsubstituted, sulphates, alkyl sulphates, phosphates, alkyl phosphates, halosulfonates, alkyl sulphonates, perhaloalkyl sulphonates, bis (perhaloalkylsulphonyl) amides, arenesulphonates, whether or not substituted with halogen or haloalkyl groups. said anions X may be identical or different in the case where n is greater than 1.

In the case where several homogeneous catalysts chosen from hydrated or non-hydrated metal salts of the general formula ", Χ _Γ , nH ₂ 0. M, X, m, n and n 'having the abovementioned meanings, are used in the process according to ^the invention, the said homogeneous catalysts can be identical or different. In a preferred embodiment, a single homogeneous catalyst chosen from hydrated or non-hydrated metal salts of general formula M _m X _n .n'H ₂ 0, M, X, m, n and n 'having the abovementioned meanings, is used in the process according to the invention. Said meta! M or said homogeneous catalyst (s) chosen (s) among the metal salts hydrated or not, selected from lanthanides is preferably selected from the following metals Ce Ce, Pr, Nd, Pm, Sm, Gd, Eu , Er, Tm, Yb.

Preferably, said metal M is selected from the following metals: Ce, Pr, Nd, Sm, Eu, Gd, Er, Yb.

Very preferably, said metal M is selected from metals: Ce and Er.

According to the invention, in the composition of the metal salt, the metal M selected from the lanthanides mentioned is associated with one or more anions X, which may be identical or different.

Preferably, X is at least one anion selected from halides, alkylsulfonates, perhaloalkylsulfonates, bis (perhaloalkylsulfonyl) amides.

 Preferably, the halide is fluoride, chloride, bromide and iodide.

 Preferably, the alkylsulfonate is mesylate and tosylate.

 Preferably, the perhaloalkylsulfonate is triflate.

 Preferably, the bis (perhaloalkylsulfonyl) amide is bis (triflimide).

Very preferably, the anion X is a chloride.

Said or said homogeneous catalyst (s) very preferred are advantageously selected from cerium chloride heptahydrate CeCI ₃ .7H ₂ 0 and erbium chloride heptahydrate ErCI ₃ .6H ₂ 0, alone or in mixture.

In the case where a single homogeneous catalyst selected from hydrated metal salts or not of general formula M _m X _n .n ^! H ₂ 0, M, X, m, n and n 'having the As above, the most preferred homogeneous catalyst is cerium chloride heptahydrate CeCi ₃ .7H ₂ O.

In a preferred embodiment, at least one second homogeneous catalyst of a different nature than said one or more homogeneous catalysts selected from the hydrated metal salts or not, having the general formula M _r "X _n .n'H ₂ 0 may optionally be added simultaneously in the same reaction chamber in which the method according to the invention is implemented.

 Preferably, said second (s) homogeneous catalyst (s) is (soni) selected from organic or inorganic Bronsted acids.

In this case, said filler is contacted simultaneously in said same enclosure réactionnelie, with a combination ^of one or more catalyst (s) homogeneous (s) chosen (s) among the metal salt hydrates or not, having the formula general Μ _{: η} Χ _η . ηΉ _? Where M, m. n, n 'and X have the abovementioned meaning of one or more second homogeneous catalysts selected from organic or inorganic Bronsted acids and one or more heterogeneous catalyst (s) ( s) according to ^the invention.

In the case where several homogeneous catalyst (s) chosen (s) from organic or inorganic Brønsted acids are used in the process according to ^the invention, said catalysts may be the same or different.

In a very preferred embodiment, said charge is brought into contact, simultaneously, in said same reaction chamber, with a combination of a homogeneous catalyst chosen from hydrated or non-hydrated metal salts having the general formula _m Xn-n'H ₂ 0 wherein m, m, n, n 'and X have the abovementioned meaning, a second homogeneous catalyst selected from organic or inorganic Bronsted acids and a heterogeneous catalyst according to ^the invention.

Preferably, inorganic Bronsted acids are chosen from the following inorganic acids: HF, HCI, HBr, HI, H ₂ S0 _3, H ₂ S0 _4, H ₃ P0 _2, H ₃ P0 _4, HN0 _{2 L} HN0 _3, H, W0 ₄ . H ₄ SiW ₁₂ 0 ₄ o, H ₃ PW ₁₂ 0 ₄ o, (NH ₄ ) ₆ (W ₁₂ O ₄₀ ) .xH ₂ O, (NH ₄ ) ₆ Mo ₇ 0 ₂₄ .xH ₂ O, H ₃ B0 ₃ , HCI0 ₄ , HBF. ₁ , HSbF ₅ , HPF ₆ , H ₂ F ₃ P, CISO ₃ H, FSO ₃ H, HN (SO ₂ F) ₂ and HI ₃ . Preferably, the inorganic Bronsted acids are chosen from the following inorganic acids: HCl, H _? SO, "H ₃ P0 _4, H ₂ 0 _3, (NH _{4) 6} (W ₁₂ O" ₀₎ .xH ₂ O _f

 A second most preferred homogeneous catalyst is hydrochloric acid (HCl).

Preferably, the organic Bronsted acids are chosen from organic acids of general formulas R-COOH. RSO ₂ H, RSO ₂ , (RSO ₂ ) NH, (RO) ₂ PO ₂ H,

Where R is a hydrogen or a carbon chain composed of alkyl or aryl groups, substituted or not by heteroatoms. Preferably, the organic acids of Bronsted are chosen from the following organic acids: formic acid, acetic acid, trifluoroacetic acid, lactic acid, levulinic acid, methanesulfinic acid, acid methanesulfonic acid, trifluoromethanesulfonic acid, bis (trifluoromethanesulfonyl) amine, benzoic acid, para-toluenesulfonic acid, 4-biphenylsulfonic acid, diphenylphosphate. and 1,1'-Binaphthyl-2,2'-diyl hydrogen phosphate.

 A second most preferred homogeneous catalyst is methanesulfonic acid.

According to the invention, said heterogeneous catalyst or catalysts comprise at least one metal chosen from metals of groups 6 to 11 and metals of group 14 of the periodic table and a support chosen from oxides of elements chosen from aluminum. , titanium, silicon, zirconium, cerium. and niobium, alone or as a mixture, and the mixed oxides chosen from zinc, copper and cobalt aluminates, said oxides possibly being doped with or not by at least one metal compound chosen from tungsten, tin and molybdenum and antimony, taken alone or as a mixture, crystallized aluminosilicates or not, aluminophosphates and amorphous or crystallized carbon compounds.

In the case where several heterogeneous catalysts are used in the process according to the invention, said catalysts may be identical or different.

Said metal chosen from metals of groups 6 to 11 and the metals of group 14 of the periodic classification of the heterogeneous catalyst (s) according to the invention are preferably chosen from the following metals: Cr, Mo, W. Mn, Te , Re, Fe, Ru, Os. Co. Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Cd, and Hg, on the one hand, and among: Ge, Sn and Pb on the other hand, taken alone or as a mixture.

 Preferably, said metal is chosen from metals Mo, W, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, on the one hand and Sn, on the other hand, taken alone and as a mixture ,

Very preferably, said metal is selected from metals Ru, Ir, Ni, Pd, Pt, on the one hand and Sn, on the other hand, taken alone and in admixture.

 Even more preferably, said metal is selected from metals Ni, Pt, on the one hand and Sn, on the other hand, taken alone and mixed. According to a preferred embodiment, the following metal mixtures are preferred: NiSn, RePt, FePt, SnPt, CuPt, IrPt, CoPt, RhPt, OsPt, RuRe, PdRe, RuSn and RuPt and even more preferably, the mixtures of following metals: NiSn, RePt, RuRe and RuPt. According to a very preferred embodiment, said metal is platinum.

In the case where the metal M of said one or more heterogeneous catalysts is chosen from the following noble metals: Ru, Os, Rh, Pd, Pt, Ag, Au, the content of noble metal on said heterogeneous catalyst or catalysts is advantageously between 0.degree. , 1% and 10% by weight and preferably between 0, 1% and 5% by weight relative to the total mass of said heterogeneous catalyst or catalysts.

In the case where the metal M of said one or more heterogeneous catalysts is chosen from non-noble metals, the content of non-noble metal on said heterogeneous catalyst or catalysts is advantageously between 0.1% and 40% by weight and preferably between 0% and 40% by weight. , 1% and 30% by weight relative to the total mass of said one or more heterogeneous catalysts.

The metal (s) of the heterogeneous catalyst (s) according to the invention are advantageously deposited on a support.

According to the invention, said heterogeneous catalyst or catalysts comprise a support chosen from oxides of the elements chosen from alumina, titanium, silica, zirconium, cerium, niobium, alone or as a mixture, and mixed oxides. chosen from zinc, copper and cobalt aluminates, said oxides possibly being doped with at least one metal compound chosen from among tungsten, tin, molybdenum and antimony, taken alone or as a mixture, aluminosilicates crystallized or not, aluminophosphates and amorphous or crystallized carbon compounds.

Preferably, crystallized aluminosilicates or not are selected from zeolites and mesostructured solids.

 Preferably, the amorphous or crystallized carbon compounds are chosen from active carbons, carbon blacks, carbon nanotubes, mesostructured carbons and carbon fibers.

 In the case where said support is chosen from doped oxides, elements selected from aluminum, titanium, silicon, zirconium, cerium, niobium, alone or as a mixture, a metallic element preferably selected from the group consisting of tungsten, tin, antimony and molybdenum, alone or in mixture, is advantageously added to said support. Preferably, the content of metal element chosen from tungsten, tin, antimony and molybdenum alone or as a mixture is advantageously between 0.1% and 30% by weight and preferably between 1 and 20% by weight. relative to the total mass of said support.

Said support is preferably hydrothermally stable, ie stable under conditions combining water and temperature. Thus, the support may undergo a treatment step aimed at improving its stability under the hydrothermal conditions of the reaction. For example, surface passivation, carbon film deposition, oxide deposition may be mentioned.

The deposition of the metal (s) chosen from groups 6 to 11 and metals of group 14 of the periodic table on said support of the heterogeneous catalyst (s) according to the invention generally involves a precursor of the metal (s). For example, it may be metal organic complexes, metal salts such as metal chlorides, metal nitrates, metal carbonates

The introduction of the metal or metals may advantageously be carried out by any technique known to those skilled in the art such as ion exchange, dry impregnation, excess impregnation, vapor deposition, etc. The introduction of metal can be carried out before or after the formatting of the support

The step of introducing the metal or metals may advantageously be followed by a heat treatment step. The heat treatment is advantageously carried out between 300 ° C. and 700 ° C. under an oxygen or air atmosphere. The heat treatment step may be followed by a temperature reduction treatment. The reducing heat treatment is advantageously carried out at a temperature of between 200 ° C. and 600 ° C. under a stream or atmosphere of hydrogen.

Preferably, said one or more heterogeneous catalysts also undergo an in situ reduction step, that is to say in the reactor where the reaction takes place, before the introduction of the reaction charge. Said reduction step may also advantageously be carried out ex-situ. The heterogeneous catalyst (s) used in the present invention may be in powder form, extruded. balls or pellets. The shaping can be carried out before or after the introduction of the metal.

The heterogeneous catalyst (s) used in the present invention are characterized by techniques known to those skilled in the art. For example, in order to characterize the metallic phase, transmission microscopy is mentioned.

Process of transformation

According to the invention, the process for transforming the feed selected from lignocellulosic biomass and carbohydrates, alone or as a mixture, is carried out in a reaction vessel in the presence of at least one solvent, said solvent being water alone or in admixture with at least one other solvent, in a reducing atmosphere and at a temperature between 50 ° ^C and 300 ° C, and at a pressure between 0.5 MPa and 20 MPa

The process is therefore carried out in a reaction vessel comprising at least one solvent and wherein said feedstock is placed in the presence of the catalytic system according to the invention. According to the invention, the process according to the invention operates in the presence of at least one solvent, said solvent being water alone or mixed with at least one other solvent.

 According to a preferred embodiment, the process according to the invention operates in the presence of water in a mixture with at least one alcohol or at least one organic solvent, under sub- or supercritical conditions.

 The alcohols are advantageously chosen from methanol, ethanol and propanols.

 The organic solvents may advantageously be chosen from tetrahydrofuran and ethyl acetate.

 In the case where said method according to the invention operates in the presence of water mixed with at least one other solvent, the solvent mixture comprises a mass content of water greater than 5% by weight and preferably greater than 30% and of very preferably greater than 50% relative to the total mass of said mixture.

According to another embodiment, the method according to the invention operates only in the presence of water. Preferably, the process according to the invention operates in the presence of at least one solvent with the exception of the solvents chosen from ionic liquids.

According to the invention, the process for converting said charge is carried out under a reducing atmosphere, preferably under a hydrogen atmosphere. Hydrogen can be used pure or as a mixture.

Preferably, said method according to the invention operates at a temperature between 50 ° C and 250 ° C and preferably between 80 ° C and 250 ° C, and at a pressure between 2 MPa and 10 MPa. Generally the method can be operated according to different embodiments. Thus, the process can advantageously be carried out batchwise or continuously, for example in a fixed bed. It can be carried out in a closed reaction chamber or in a semi-open reactor. Said homogeneous catalysts are advantageously introduced into the reaction chamber in an amount corresponding to a homogeneous charge / catalyst mass ratio of between 1.5 and 1000, preferably between 5 and 1000, and preferably between 10 and 500.

The heterogeneous catalyst or catalysts are introduced into the reaction chamber in an amount corresponding to a heterogeneous charge / catalyst mass ratio (s) of between 1 and 1000, preferably between 1 and 500, preferably between 1 and 500. and 100, preferably between 1 and 50 and more preferably between 1 and 25. The heterogeneous catalyst (s) introduced into the reactor can undergo a reducing heat treatment step before the reaction. introduction of the reaction charge. The reducing heat treatment is preferably carried out at a temperature of between 150 ° C. and 600 ° C. under a stream or atmosphere of hydrogen. The feedstock is introduced into the process in an amount corresponding to a mass ratio solvent / feed of between 1 and 1000, preferably between 1 and 500 and more preferably between 5 and 100.

If a continuous process is chosen, the hourly mass velocity (mass charge rate / mass of heterogeneous catalyst (s)) is between 0.01 and 5 h ^-1 , preferably between 0.02 and 2 h ¹ .

The products obtained and their method of analysis

 The products of the reaction of the conversion process according to the invention are mono- or polyoxygenated compounds. Said mono- or polyoxygenated compounds are soluble in water.

 Said mono- or polyoxygenated compounds are advantageously constituted by monosaccharides and their derivatives, oligosaccharides, and also soluble polymers advantageously formed by successive combinations of the monosaccharide derivatives.

Per monosaccharide denotes a carbohydrate having a composition of C _n H _2n O _n where n is greater than 2, obtained by total hydrolysis of cellulose, or hemicellulose. or starch. Monosaccharides are simple sugars that are produced by complete depolymerization of cellulose and / or hemicellulose, such as, in particular, glucose, galactose, mannose, xylose, fructose, etc.

Derivatives of monosaccharides and oligosaccharides are those products that can be obtained for example by dehydration, isomerization, reduction or oxidation:

 sugar alcohols, alcohols and polyols: in particular celiobitol, sorbitol, anhydrosorbitol, hexanetetrol, hexanetriols, hexanediols, xylitol, pentanetetric, pentanetriols, pentanediols, erythritol, butanetriols, butanediols, glycerol, 1,3-propanediol, propylene glycol, ethylene glycol, hexanols, pentanols, butanols, propanols, ethanol, etc.

 monocetones, polyketones; hydroxyacetone, 2,5-hexanedione. .

 carboxylic acids and their esters, lactones: formic acid, alkyl formates, acetic acid, alkyl acetates, hexanoic acid, alkyl hexanoates, levulinic acid, levulinates alkyls, lactic acid, alkyl lactates, glutaric acid, alkyl glutarates, 3-hydroxypropanoic acid, 3-hydroxybutyrolactone, γ-butyrolactone, γ-valerolactone

cyclic ethers: for example tetrahydrofuran (THF), 3-methyltetrahydrofuran (Me-THF) and its positional isomers, 2,4-dimethyltetrahydrofuran and its positional isomers, tetrahydropyran-2-methanol and its isomers of position.

 furans: furan-2,5-dicarboxylic acid, 5- (hydroxymethyl) furfural, furfural ...

By "self-soluble polymers" is meant all the products resulting from the condensation between monosaccharides, oligosaccharides and / or derivatives of monosaccharides. At the end of the reaction, the reaction medium is removed and centrifuged. 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 amount of 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.

EXAMPLES

In the examples below, the tungsten zucone catalyst (Zr0 ₂ -WO _x ) is commercially available from MEL Chemicals and contains 10.3% tungsten by weight. Catalyst C9 (Pt (5%) on activated charcoal) is sold by Alfa Aesar.

The simple oxide supports Zr0 ₂ , Ti0 ₂ and Ce0 ₂ and the mixed oxide support Zr0 ₂ -Ce0 ₂ are commercial.

S1 supports (Ce0 ₂ -WO _x) and S2 (Zr0 ₂ -Ce0 -W0x ₂₎ are prepared by dry impregnation of a metatungstate solution ^of ammonium (NH) ₄ H ₂ W ₁₂ 04O followed by calcining in dry air at 550 ° C for 3h. The mass content of tungsten measured by X-ray fluorescence is 8.3% by weight relative to the weight of the support for S1 and 8.5% by weight relative to the weight of the support for S2.

Cerium chloride heptahydrate CeCl ₃ .7H ₂ O constituting the homogeneous catalyst is commercial and used without purification.

EXAMPLE 1 Preparation of Heterogeneous Catalysts C1, C2, C3 C4. C5. C6 and C7 comprising 0.5% by weight Pt on a support containing an oxide, doped or not, or a mixed oxide, doped or not.

An aqueous solution of hexachloroplatinic acid H ₂ PtCl ₆ .xH ₂ 0 to 1, 9% by weight (25mL, 0.475 g) is added at room temperature to the oxide support (24 g) previously desorbed under vacuum (1 h, 100.degree. ° C). The mixture is stirred for one hour and then evaporated. The solid obtained is then dried in ^an oven at 110 ° C. for 24 hours. The solid is calcined under a dry nitrogen flow rate at the temperature of 150 ° C. for 1 h, then at 250 ° C. for 1 hour, then at 350 ° C. for 3 hours and finally at 420 ° C. for 4 hours. It is then reduced under hydrogen flow at 500 ° C for two hours. The heterogeneous catalysts obtained contain 0.5% by weight of platinum relative to the total weight of said catalysts. The formulations of the catalysts prepared are summarized in Table 1. Table 1: Formulation of heterogeneous catalysts C1 to 01.

Exemple 2 : Transformation de la cellulose mettant en œuyre les catalyseurs C1 . C2, C3, C4, C5, C6 et C7 en combinaison avec le catalyseur homogène CeCI₃.7H?0.

Example 2 Transformation of the Cellulose Using the C1 Catalysts C2, C3, C4, C5, C6 and C7 in combination with the homogeneous catalyst This ₃ .7H? 0.

Example 2 relates to the conversion of cellulose from a combination of a C1 to C7 heterogeneous catalyst described in Example 1 and ^a homogeneous catalyst consisting of a metal salt This ₃ .7H ₂ 0 for production of mono- and polyoxygenated products.

50mL of water, 1.3 g of SigmaCell® cellulose, 26 mg of CeCI ₃ .7H ₂ O and 0.55 g of heterogeneous catalyst are introduced into an autoclave of OOmL under a nitrogen atmosphere. The metal salt is soluble in water at T = 25 ° C and atmospheric P = P.

The homogeneous catalyst CeCl ₃ .7H ₂ O is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / CeCl ₃ .7H ₂ O = 50

The heterogeneous catalysts are introduced into the reaction chamber in an amount corresponding to a heterogeneous charge / catalyst mass ratio = 2.5.

The feedstock is introduced into the autoclave in an amount corresponding to a mass ratio solvent / feed = 38.

The autoclave is heated to 230 ° C. and a pressure of 5 MPa of hydrogen is introduced. After 12h reaction _, the reaction medium is removed and centrifuged. Samples are also taken during the test and analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the conversion product content of the aqueous solution.

The results obtained are referenced in Table 2

Table 2: Solubilization of cellulose and formation of humins

The use of a combination of a homogeneous CeCl ₃ .7H ₂ O catalyst and a heterogeneous C1 to C7 catalyst makes it possible to increase the conversion of the feed from 50% to 55% for the catalyst C2. from 50% to 63% and 65% for C7 catalysts.

C4 and Cl, and from 50% to 75% and 85% and 87% for catalysts C5, C6 and C3.

The simultaneous use of a homogeneous catalyst chosen from metal salts in which the metal M is chosen from among the lanthanides and a heterogeneous catalyst, in the same reaction chamber makes it possible to further reduce the non vaiorisabies products, such as humins unlike the test carried out in the absence of heterogeneous catalyst.

EXAMPLE 3 Transformation of the Cellulose Using Catalyst C3 in Combination with the Homogeneous Catalyst CeCl ₃ .7H 2 O under Variable Operating Conditions

Example 3 relates to the conversion of cellulose from a combination of a heterogeneous catalyst C3 0.5% Pt / CeO ₂ described in Example 1 and a homogeneous catalyst consisting of a metal salt CeCl ₃ .7H ₂ 0 for the production of mono- and polyoxygenated products.

In 100ml_ of autoclave was charged with 50ml_ of ^water, 1, 3 g of cellulose SigmaCell®, 26mg of this ₃ .7H ₂ 0 and 0.55 g of heterogeneous catalyst C3 under a nitrogen atmosphere.

The metal salt is soluble in water at T = 25 ° C and atmospheric P = P.

The homogeneous catalyst CeCI ₃ .7H ₂ 0 is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / CeCl ₃ .7H ₂ O = 50 The heterogeneous catalysts are introduced into the reaction chamber at a rate of an amount corresponding to a heterogeneous charge / catalyst mass ratio = 2.5.

The feedstock is introduced into the autoclave in an amount corresponding to a mass ratio solvent / feed = 38.

The autoclave is heated to a temperature T between 190 ° C and 250X and a pressure P ranging between 2 MPa and 10MPa of hydrogen is introduced. After 6 hours of reaction, the reaction medium is removed and centrifuged. Samples are also taken during the test and analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products of the aqueous solution.

The results obtained are referenced in Table 3. Table 3: Cellulose Conversion and Humin Formation

Increasing the heating temperature from 190 to 210 and 230 ° C. makes it possible to increase the conversion of cellulose from 30% after 12 hours to 67% and 91%, respectively, after 12 hours, in the presence of the homogeneous CeCI ₃ catalyst. .7H ₂ O and heterogeneous catalyst C1. This increase is not accompanied by the formation of humins. The use of more severe operating conditions at 240 ° C. and 250 ° C. with a hydrogen pressure of 50 bar, or at 230 ° C. with 80 bar of hydrogen also makes it possible to overcome the formation of humines. while maintaining high cellulose conversion values.

Example 4: Transformation of the cellulose using œuyre catalyst C3 in combination with the homogeneous catalyst ErClr _{j .6H?} 0.

Example 4 relates to the conversion of cellulose from a combination of a C3 0.5% Pt / CeO ₂ heterogeneous catalyst described in Example 1 and a catalyst Homogeneous composition consisting of a metal salt ErCI ₃ .6H ₂ O for the production of mono- and polyoxygenated products.

50mL of water, 1.3g of SigmaCell® cellulose, 28mg of ErCl ₃ .6H ₂ O and 0.55g of heterogeneous catalyst C ₃ are introduced into an autoclave of 50mL of water under a nitrogen atmosphere. The metal salt is soluble in water at T = 25 ° C and atmospheric P = P.

The homogeneous ErCI ₃ .6H ₂ O catalyst is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / ErCl ₃ .6H ₂ O = 50

 The heterogeneous catalysts are introduced into the reaction chamber in an amount corresponding to a heterogeneous charge / catalyst mass ratio = 2.5.

The feedstock is introduced into the autoclave in an amount corresponding to a mass ratio solvent / feed = 38.

The autoclave is heated to 230 ° C. and a pressure of 5 MPa of hydrogen is introduced. After 12h reaction the reaction medium is removed and centrifuged. Samples are also taken during the test and analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products of the aqueous solution.

The results obtained are referenced in Table 4.

Table 4: Cellulose Conversion and Humin Formation

The simultaneous use of a homogeneous catalyst chosen from metal salts in which the metal M is chosen from lanthanides and a heterogeneous catalyst, in the same reaction chamber makes it possible to significantly reduce the content of non-recoverable products, such as humins compared to the test carried out in the absence of heterogeneous catalyst.

Example 5; _: Glucose Transformation using œuyre catalyst C3 in combination with the homogeneous catalyst CiC g.7H _z O.

Example 5 relates to the conversion of cellulose from a combination of a heterogeneous catalyst C3 described in Example 1 and a homogeneous catalyst consisting of a metal salt CeCl ₃ .7H ₂ O for the production of mono- and polyoxygenated products.

 In an autoclave of 100 ml, 50 ml of water and 1.3 g of SigmaCell® cellulose are introduced.

26 mg of CeCl ₃ .7H ₂ O and 0.55 g of heterogeneous catalyst C 3 under a nitrogen atmosphere. The metal salt is soluble in water at T = 25 ° C and atmospheric P = P.

The homogeneous catalyst CeCI ₃ .7H ₂ 0 is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / CeCl ₃ .7H ₂ O = 50 The heterogeneous catalysts are introduced into the reaction chamber at a rate of an amount corresponding to a heterogeneous charge / catalyst mass ratio = 2.5. The feedstock is introduced into the autoclave in an amount corresponding to a mass ratio solvent / feed = 38.

The autoclave is heated to 230 ° C. and a pressure of 5 MPa of hydrogen is introduced. After 12h reaction the reaction medium is removed and centrifuged. Samples are also taken during the test and analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products of the aqueous solution.

The results obtained are referenced in Table 5. Table 5: Glucose Conversion and Humin Formation

The simultaneous use of a homogeneous catalyst chosen from metal salts in which the metal M is chosen from lanthanides and a heterogeneous catalyst, in the same reaction enclosure containing a saccharide type filler makes it possible to significantly reduce the content of the products. not valued, such as humins compared to the test carried out in the absence of heterogeneous catalyst. Example 6 Preparation of the C8 heterogeneous catalyst comprising 10% Ni by weight on a CeQy support

An aqueous solution of nickel nitrate hexahydrate Ni (N0 ₃ ) ₂ .6H ₂ 0 to 15% by weight (50mL, 7.4g) is added at room temperature to the carrier cerium oxide Ce0 ₂ (14g) previously desorbed under vacuum ( 1 h, 100 ° C.) The mixture is stirred for one hour and then evaporated, the solid obtained is then dried in an oven at 110 ° C. for 24 hours and the solid is calcined under a flow of dry nitrogen at room temperature. 150 ° C for 1 h, then 250 ° C for 1 h, then 350 ° C for 3h and finally 420 ° C for 4h It is then reduced under hydrogen flow at 500 ° C for two hours. The heterogeneous catalysts obtained contain 10% by weight of nickel relative to the total mass of said catalysts.

The formulation of the catalyst prepared is summarized in Table 6. Table 6: Formulation of the C8 heterogeneous catalyst.

 Composition Catalyst

C8 10% Ni / CeO ₂ Example 7; Transformation, cellulose using C8 catalyst in combination with the homogeneous catalyst CeC! ₃ 7H? 0. Example 7 relates to the conversion of cellulose from a combination of a heterogeneous catalyst C8 described in Example 6 and a homogeneous catalyst consisting of a metal salt CeCI ₃ .7H ₂ 0 for the production of mono- and polyoxygenated products.

In a 100mL autoclave, 50mL of water, 1.3g of SigmaCell® cellulose, 26mg of CeCl ₃ .7H ₂ O and 0.55g of heterogeneous C8 catalyst are introduced under a nitrogen atmosphere. The metal salt is soluble in water at T = 25 ° C and atmospheric P = P.

The homogeneous catalyst CeCI ₃ .7H _? 0 is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / CeCl ₃ .7H ₂ 0 = 50 The heterogeneous catalysts are introduced into the reaction chamber in an amount corresponding to a mass ratio charge / heterogeneous catalyst = 2.5.

The feedstock is introduced into the autoclave in an amount corresponding to a mass ratio solvent / feed = 38.

The autoclave is heated to 230 ° C. and a pressure of 5 Pa of hydrogen is introduced. After 12h reaction the reaction medium is removed and centrifuged. Samples are also taken during the test and analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products of the aqueous solution.

The results obtained are referenced in Table 7. Table 7: Cellulose Conversion and Humin Formation

The simultaneous use of a homogeneous catalyst chosen from metal salts in which the metal M is chosen from lanthanides with the exception of the element La, and a heterogeneous catalyst containing nickel, in a single reaction chamber containing a polysaccharide charge makes it possible to significantly reduce the content of non-recoverable products, such as humins, unlike the test carried out in the absence of a heterogeneous catalyst.

Example 8: Transformation of _. the _. cellulose using the C9 catalyst in combination with the Catalyst CeCI ₃ .7H ₂ 0 _i catalyst.

Example 8 relates to the conversion of cellulose from a combination of heterogeneous catalyst C9 and a homogeneous catalyst consisting of a metal salt

CeCl ₃ .7H ₂ O for the production of mono- and polyoxygenated products.

 In a 100mL autoclave, 50mL of water, 1.3g of SigmaCell® cellulose, are introduced.

25mg of CeCi ₃ .7H ₂ 0 and 55mg of heterogeneous C9 catalyst under a nitrogen atmosphere.

The metal salt is soluble in water at T = 25 ° C and atmospheric P = P.

The homogeneous catalyst CeCl ₃ .7H ₂ 0 is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / CeCl ₃ .7H ₂ O = 10.

The heterogeneous catalysts are introduced into the reaction chamber in an amount corresponding to a heterogeneous charge / catalyst mass ratio = 24.

The feedstock is introduced into the autoclave in an amount corresponding to a mass ratio solvent / feed = 38. The autoclave is heated to 230 ° C. and a pressure of 5 MPa of hydrogen is introduced. After 12h reaction the reaction medium is removed and centrifuged. Samples are also carried out during the test and analyzed by high pressure liquid chromatography (HPLC) using the refractometer to determine the content of ^'the aqueous solution conversion products.

The results obtained are referenced in Table 8. TABLE 8 Cellulose Conversion and Humin Formation

The simultaneous use of a homogeneous catalyst chosen from metal salts in which the metal M is chosen from lanthanides with the exception of the element La, and a heterogeneous catalyst containing platinum, in the same reaction chamber containing a polysaccharide charge makes it possible to significantly reduce the content of non-valuable products, such as humins, unlike the test carried out in the absence of a heterogeneous catalyst. The weight ratio ethylene glycol / propylene glycol is less than 8.

Example 9: Transformation of cellulose using œuyre catalyst C9 ayec in _combination: the homogeneous catalyst _H: wcy (non-compliant)

Example 9 relates to the conversion of cellulose from a combination of heterogeneous catalyst C9 and a homogeneous catalyst consisting of a Bronsted H ₂ WO ₄ acid for the production of mono- and polyoxygenated products.

In a 100mL autoclave. 50 ml of water, 1.3 g of SigmaCell® cellulose, 130 mg of H ₂ WO ₄ and 55 mg of heterogeneous catalyst C 9 are introduced under a nitrogen atmosphere. Bronsted acid H ₂ WO ₄ is insoluble in water at T = 25 ° C and atmospheric P = P.

The homogeneous catalyst H _? WO _; is introduced into the reaction chamber in an amount corresponding to a mass ratio load / H ₂ W0 ₄ = 10.

 The heterogeneous catalyst is introduced into the reaction chamber in an amount corresponding to a heterogeneous charge / catalyst mass ratio = 24.

The charge is introduced into the autoclave in an amount corresponding to a mass ratio solvent / charge = 38.

The autoclave is heated to 230 ° C. and a pressure of 5 MPa of hydrogen is introduced. After 12h reaction the reaction medium is removed and centrifuged. Samples are also taken during the test and analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products of the aqueous solution.

The results obtained are referenced in Table 9.

Table 9: Cellulose Conversion and Humin Formation

The simultaneous use of a homogeneous catalyst selected from Bronsted acids and a heterogeneous catalyst containing platinum, in the same reaction vessel containing a polysaccharide charge, makes it possible to significantly reduce the content of non-recoverable products, such as humins contrary to the test carried out in the absence of heterogeneous catalyst. However, the weight ratio ethylene glycol / propylene glycol is greater than 8.

Claims

1. Process for transforming a feedstock chosen from lignocellulosic biomass and carbohydrates, alone or in a mixture, into mono- or polyoxygenated compounds, in which said feedstock is brought into contact, simultaneously, with a combination of one or more catalysts (s) homogeneous(s) and one or more heterogeneous catalysts, in the same reaction chamber, in the presence of at least one solvent, said solvent being water alone or mixed with at least one other solvent, under reducing atmosphere, and at a temperature between 50°C and 300°C, and at a pressure between 0.5 MPa and 20 MPa, in which, said homogeneous catalyst(s) being chosen from hydrated or _non -hydrated metal salts, having _the general formula M _m Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, m is an integer between 1 and 10, n is an integer between 1 and 10 and n' is a number between 0 and 20 and , phosphates, alkylphosphates, halogenosulfonates, alkylsulfonates, perhaloalkylsulfonates. b!S (perhaloalkylsulfonyl) amides, arenesulfonates, substituted or not by halogen or haloalkyl groups, said anions X possibly being identical or different in the case where n is greater than 1, said heterogeneous catalyst(s) comprising at least one metal chosen from the metals of groups 6 to 1 1 and the metals of group 14 of the periodic table and a support chosen from the oxides of the elements chosen from aluminum , titanium, silicon, zirconium, cerium, and niobium, alone or in mixture, and mixed oxides chosen from zinc, copper and cobalt aluminates, said oxides being able to be doped or not with at least one metallic compound chosen from tungsten, tin, molybdenum and antimony, taken alone or as a mixture, aluminosilicates, crystallized or not, aluminophosphates and amorphous or crystallized carbon compounds. 2. Method according to claim 1 in which the metal M of said homogeneous catalyst(s) chosen from hydrated or non-hydrated metal salts is chosen from the following metals: Ce, Pr, Nd, Pm, Sm, Gd, Eu, Er, Tm, Yb. 3. Method according to one of claims 1 or 2 in which the metal M of said homogeneous catalyst(s) chosen from hydrated or non-hydrated metal salts is chosen from the following metals: Ce, Pr , Nd, Sm, Eu, Gd, Er, Yb. 4. Method according to one of claims 1 to 3 in which the anion X of the first catalyst is at least one anion chosen from halides and alkylsulfonates. perhaloalkylsulfonate, bis(perhaloalkylsulfony!)amides. 5. Method according to one of claims 1 to 4 in which at least a second homogeneous catalyst chosen from organic or inorganic Bronsted acids is added, simultaneously, in said same reaction chamber. 6. Method according to claim 5 in which the Bronsted inorganic acids are chosen from the following inorganic acids: HF, HCI. HBr, Hl, H ₂ S0 ₃ , H ₂ S0 ₄ , Η ₃ Ρ0 ₂ , H ₃ PO ₄ , ΗΝ0 ₂ , HNO ₃ , H ₂ W0 ₄ , H ₄ SiW ₁₂ 0 ₄ o, H ₃ PW ₁₂ O ₄₀ , (NH ₄ ) ₆ (W ₁₂ O ₄₀ ).xH ₂ O, (NH ₄ ) ₆ MB ₇ 0 _?4 .xH _? 0. H ₃ B0 ₃ , HCI0 ₄ , HBF _4l HSbF ₅ . HPF ₆ , H ₂ F0 ₃ P, CIS0 ₃ H. FS0 ₃ H, HN(S0 ₂ F) ₂ and HIO ₃ . 7. Process according to claim 6 in which the second homogeneous catalyst is hydrochloric acid (HCI), 8. Method according to one of claims 1 to 5 in which the organic Bransted acids are chosen from organic acids of general formulas R-COOH. RSO _? H. RSO ₃ H, (RS0 ₂ )NH, (RO) ₂ P0 ₂ H, ROH where R is a hydrogen or a carbon chain composed of alkyl or aryl groups, substituted or not by heteroatoms. 9. Method according to one of claims 1 to 8 in which the metal of the heterogeneous catalyst(s) is chosen from the metals Mo, W, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, on the one hand and Sn, on the other hand, taken alone and in a mixture. 10. Method according to one of claims 1 to 9 in which the homogeneous catalysts are introduced into the reaction chamber in a quantity corresponding to a mass ratio of filler/homogeneous catalyst(s) of between 1.5 and 1000, 1 1. Method according to one of claims 1 to 10 in which, in the case where said process operates in the presence of water mixed with at least one other solvent, the mixture of solvents comprises a water mass content greater than 5 % by weight and preferably greater than 30% and very preferably greater than 50% relative to the total mass of said mixture. 12. Method according to one of claims 1 to 10 in which said method operates only in the presence of water. 13. Method according to one of claims 1 to 12 in which the process operates in the presence of at least one solvent with the exception of solvents chosen from ionic liquids, 14, Method according to one of the preceding claims in which the reducing atmosphere is a hydrogen atmosphere, pure or mixed. 15. Method according to one of the preceding claims operating at a temperature between 50°C and 300X, and at a pressure between 0.5 MPa and 20 Pa.