WO2019038068A1 - Aluminic material comprising carbon and use of same as a catalyst for transforming biosourced products - Google Patents

Abstract

The invention concerns a crystalline aluminic material comprising a carbonaceous deposit, the amount of deposited carbon being between 1 and 15 wt% of the total weight of the material, prepared by a method comprising at least one step of bringing a mixture comprising at least one carbonaceous precursor into contact with a crystalline aluminic solid, a step of heat treating the solid, and the repetition of the steps of bringing into contact and heat treatment, and a catalyst comprising this material and a method utilising this catalyst.

Description

 ALUMINUM MATERIAL COMPRISING CARBON AND ITS USE AS CATALYST FOR PROCESSING BIOSOURCES PRODUCTS

TECHNICAL AREA

The present invention relates to the field of stable materials in hydrothermal conditions and in particular to the field of composite materials C / Al2O3. It also relates to the field of catalysts for transforming biomass and its derived compounds into key or innovative chemical intermediates for petrochemicals or hydrocarbons. It also relates to the preparation of these materials which are obtained according to a specific process of adsorption / pyrolysis cycles. The invention also relates to the use of said materials as catalysts in processes for the direct or indirect transformation of lignocellulosic biomass into polyols, diols or alcohols. An example is the production of biosourced ethylene glycol and propylene glycol from lignocellulosic biomass or sugars for the biobased polymer market.

PRIOR ART The energy and environmental challenges of the XXI ^century require to develop alternatives to the use of fossil resources. One of the solutions envisaged is to use oxygenated compounds derived from biomass. Among the possible processes, enzymes, microorganisms, bases and mineral acids are mature technologies already used. However, they have certain disadvantages such as slow kinetics, large solvent volumes to be treated (especially in the case of biotechnological processes), the difficulty of separating the homogeneous catalyst products as well as risks of corrosion, which can make the processes too difficult. expensive and polluting.

The use of solid catalysts circumvents these problems, eliminates certain process steps and thus reduces energy consumption and waste generation.

The use of heterogeneous catalysts is envisaged in the direct transformation of lignocellulosic biomass into products of interest for chemistry and petrochemistry (alcohols, diols, olefins, alkanes, etc.). Heterogeneous catalysts are also used for the indirect transformation of lignocellulosic biomass, that is to say for the transformation of intermediate products obtained such as for example cellulose, hemicellulose, simple and complex sugars, alcohols, polyols, diols, carboxylic acids, carbonyl compounds or any organic compound. All of these transformations allow access new biobased products or alternatives to existing "petro-hardened" products.

To achieve this, it is necessary to design catalysts capable of selectively removing the oxygen element, including via specific acidic and / or basic properties. In addition, the addition of a metallic phase makes it possible, via oxidation or reduction reactions, to access new product families.

The transformation of lignocellulosic biomass and its derivatives generally imposes an aqueous medium or containing water in the liquid phase under the action of temperature and pressure (so-called hydro-thermal conditions or HT). Indeed, water is often produced in situ by dehydration of certain reagents or products and / or may be a solvent of choice for the targeted reactions. Therefore, it is interesting to develop heterogeneous catalysts with hydrothermal stability properties in the liquid phase. However, the use of catalysts based on conventional oxide supports (silica, transition aluminas, etc.) is excluded, due to the strong degradation of the intrinsic properties (textural, structural, etc.) of these oxides under these specific conditions. For example, the "γ" transition alumina, which is widely used as a catalyst support in the field of refining and petrochemistry, is converted into liquid phase oxy (hydroxy) of aluminum (AlOOH) of the boehmite type in the liquid phase. around 200 ° C.

To overcome this problem, a possible strategic axis is to protect the surface of conventional oxide supports by a thin layer of carbon. This has notably been achieved by adsorption at ambient temperature of carbon precursors of the "sugar" type in solution on the surface of silicas, mesostructured silicas, aluminas, etc. and pyrolysis of these sugars (high temperature calcination in an oxygen-poor medium) in order to generate said carbonaceous layer (WO 2013/169391). The resulting C / oxide composite is characterized by a deposited carbon content of 10 to 25% by weight relative to the weight of the catalyst and a surface reactivity associated with the partial conversion of the starting sugars into a partially functionalized thin carbon layer (reaction temperature). pyrolysis below 600 ° C), thereby providing specific catalytic behavior combined with increased hydrothermal stability over unprotected starting oxide. A second possible option is to carry out carbon deposition by CVD (CVD = Chemical Vapor Deposition) of a carbon precursor (methane, ethylene, benzene) in a high temperature range (600 to 900 ° C) (Vissers et al., J. CataL, 1988, 114, 2, 291, Xiong et al., Angew Chem Int Ed, 2015, 54, 27, 7939). It is reported that the C / Al 2 O 3 materials obtained are stable under HT conditions only for minimum contents of deposited carbon of 35% by weight relative to the weight of the catalyst. Content the weight of the carbon to be deposited, which is necessary to induce total protection of the surface of the starting transition alumina, is therefore different according to the proposed synthesis methodologies, which implies that the latter have an impact on the nature and intrinsic properties of the carbon deposit produced and therefore those of the catalyst. In all cases, said weight content of carbon is not negligible and can strongly impact the properties, including textural and surface reactivity, of the oxide and in particular of the initial transition alumina, and adversely affect performance associated catalysts depending on the intended application.

Another possible strategy, in the case of the protection of aluminum solids, is not to synthesize solid C / Al 2 O 3 composites but to use the adsorption capacity of the aluminum surface with respect to specific organic molecules, such as polyols for example, directly under HT conditions (Ravenelle et al., Top Catal., 2012, 55, 3, 162). This method nevertheless has several major disadvantages such as the impossibility of protecting the aluminum support before the deposition of the active metal phase, the need to achieve and control this protection "in situ" during the catalytic test (or during the pre-treatment of the latter ) and the difficulty of regenerating said catalyst during a possible implementation in cyclic processes.

OBJECT AND INTEREST OF THE INVENTION

The present invention relates to a method of preparation, as well as a crystalline aluminum material comprising a carbonaceous deposit prepared by a process comprising: a) a step of contacting a mixture comprising at least one carbon precursor with a crystalline aluminum solid at a temperature of between 50 and 300 ° C. at a pressure corresponding at least to the autogenous pressure, the concentration of carbon precursor in said mixture being between 2 and 100 g / l, the weight ratio precursor carbon / solid aluminum in the suspension constituted said mixture and crystalline aluminum solid being between 0.1 and 2; b) a heat treatment step of the solid obtained at the end of step a); c) repeating steps a) and b) until the desired deposited carbon content is reached; d) a step of depositing at least one metal belonging to columns 4 to 14 of the periodic table according to the classification of IUPAC or the family of internal transition metals on the solid obtained at the end of step c); e) a possible heat treatment step of the solid obtained at the end of step d).

The invention also relates to a process for converting a biosourced feed into mono- and poly-oxygenated compounds using a catalyst comprising said crystalline aluminum material and at least one metal belonging to columns 4 to 14 of the periodic table according to the classification of IUPAC or the family of internal transition metals in a reaction chamber in the presence of at least one solvent, said solvent containing water, under a neutral, reducing or oxidizing atmosphere, and at a temperature of between 100 ° C. and 300 ° C, and at a pressure of between 0.1 MPa and 50 MPa, the mass ratio filler / material being between 1 and 1000. It was surprisingly discovered that a crystalline aluminum material comprising a deposit carbon as described in the present invention, exhibited a remarkable hydrothermal stability when it is used in hydrothermal conditions for carbon contents deposited relatively weak. It is thus possible to have a stable catalyst, prepared "ex situ" at the completion of the catalytic reaction, which simplifies the conversion process implement this catalyst by not having to integrate the preparation steps or conditioning the catalyst "in situ".

Characterization techniques

The material according to the invention is in particular described using the following characterization techniques: nitrogen volumetry and X-ray diffraction (XRD). Nitrogen volumetry, corresponding to the physical adsorption of nitrogen molecules in the porosity of the material via a progressive increase in pressure (Ρ / Ρ0, with P0 = atmospheric pressure) at constant temperature, provides information on the textural characteristics pore diameter, pore volume, specific surface) of the material according to the invention. Specific surface area is understood to mean the BET specific surface area (SBET in m ² / g) determined by nitrogen adsorption according to the ASTM D 3663-78 standard established from the BRUNAUER-EMMETT-TELLER method described in the "The Journal of the American Society, 1938, 60, 309. The representative porous distribution of a mesopore population centered in a range of 2 to 50 nm is determined by the Barrett-Joyner-Halenda model (BJH). The nitrogen adsorption-desorption isotherm according to the BJH model thus obtained is described in the periodical "The Journal of the American Society", 1951, 73, 373, written by EP Barrett, LG Joyner and PP Halenda. In the following description, the diameter of the mesopores φ of the material according to the invention corresponds to the maximum diameter obtained on the curve of the porous desorption distribution. Similarly, the pore volume (Vp) corresponds to the volume obtained at the maximum value of P / PO. In addition, the shape of the nitrogen adsorption isotherm and the hysteresis loop can provide information on the nature of the mesoporosity.

The X-Ray Diffraction technique is used to characterize a crystallized solid, defined by the repetition of a unitary unit (or unit cell) at the molecular level. In the following discussion, the X-ray analysis is performed on powder with a diffractometer operating in reflection and equipped with a rear monochromator using copper radiation (wavelength 1.5406 A). The lines usually observed on the diffractograms corresponding to a given value of the angle 2Θ are associated with the inter-reticular distances d (hki) characteristic of the structural symmetry of the material, ((hkl) being the Miller indices of the reciprocal lattice) by the Bragg relation: 2 d (hki) * sin (θ) = n * λ. This indexing then allows the determination of the mesh parameters (abc) of the direct network, the value of these parameters being a function of the crystallographic structure of the material according to the invention. Thus, this technique provides access to the nature of the crystallographic phase, the size of the crystallites and the degree of crystallinity of the material according to the invention. The mass quantization of the boehmite phase (AlOOH), possibly generated, is estimated from the first diffraction line corresponding to X-ray diffraction by the plane (020) of the crystal lattice of boehmite. The maximum content corresponds to the area under the line of a sample containing 100% of a boehmite phase prepared by a 10-hour hydrothermal treatment at 200 ° C. from a reference alumina. DETAILED DESCRIPTION OF THE INVENTION

The term "crystalline aluminic material" means any aluminum compound belonging to the family of transition aluminas as well as alpha alumina (or corundum) and their derivatives which result from the dehydration of aluminum trihydroxide precursor aluminum precursor materials (gibbsite, bayerite, norstandite, doyleite) or oxy (hydroxy) aluminum (boehmite, diaspore), that is to say part of the following non-exhaustive list: gamma, delta, theta, eta, rho, chi aluminas, kappa. By solid derivatives of transition aluminas and alpha alumina is meant any transition alumina or alpha alumina which would include one or more additional elements, such as beta alumina which is stabilized by alkaline ions. The carbon content deposited on the crystalline aluminic material prepared according to the invention is between 1 and 15% by weight relative to the total mass of said material, preferably between 1 and 9% by weight and even more preferably between 1 and 7% weight It has surprisingly been found that the aluminum material prepared according to the invention is stable under hydrothermal conditions, that is to say that the maintenance of its intrinsic and in particular structural properties under hydrothermal conditions is mainly observed. More precisely, the crystallographic phase of the crystalline aluminic material prepared according to the invention is preserved at more than 85%, preferably at more than 88%, even more preferably at more than 90%, and very preferably at more than 90%. 95%, this value being determined by X-ray diffraction analysis. Similarly, the textural parameters (specific surface area in m ² / g, pore volume in ml / g and pore diameter in nm, determined by the analysis Volumetry to nitrogen) are generally conserved, although the observed differences are more pronounced than those previously described for the structural aspect. Indeed, the carbonaceous deposit which characterizes the material according to the invention logically leads to a modification of the surface of the starting crystalline aluminic support (and therefore a modification of the texture), without in any way jeopardizing the stability of the material according to the invention. 'invention. In addition, the small amount deposited according to the invention limits these variations and leads to a maintenance of more than 80%, preferably 90%, of the specific surface, more than 65%, preferably 70%, of the diameter of the pores and more than 50%, preferably 60%, of the pore volume. In all cases, the porous nature of the starting crystalline aluminic support is retained, which ensures the use of the material according to the invention in the targeted application areas. In parallel, the integrity of the material according to the invention is ensured by a minimal dissolution of the latter, which results in a leaching of aluminum element in the final solution after hydrotreatment less than 10%, preferably less than 5% and even more preferably less than 2% relative to the initial amount of aluminum contained in the material. Similarly, in the case of the possible addition of at least one metal, the integrity of the metal phase of the material according to the invention is ensured by a minimal dissolution of the latter, which results in a leaching in the minus the metallic element in the final solution after hydrotreatment less than 10%, preferably less than 5% and even more preferably less than 2% relative to the initial amount of at least the metal element contained in the material .

By hydrothermal conditions is meant bringing into contact, in an autoclave, the crystalline aluminum solid prepared according to the invention with a solution comprising water, the whole medium then being brought to a temperature of between 50 and 300 ° C. , the pressure corresponding at least to the autogenous pressure associated with the chosen temperature. The contacting can be carried out under an oxidizing atmosphere (air), neutral (inert gas: dinitrogen, argon, etc.) or reducing, that is to say partially or completely composed of dihydrogen. In a preferred manner, the atmosphere is air. The solution is neutral, acidic or basic and preferably neutral. The crystalline aluminum material prepared according to the invention has properties, in particular properties of resistance to hydrothermal conditions, which make its use as a catalyst support particularly judicious.

A catalyst comprising the material prepared according to the invention advantageously comprises at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals, namely lanthanides and actinides. The at least one metal is advantageously chosen from the following non-exhaustive list: Ce, La, Ti, Zr, Nb, Ta, V, Cr, Mo, W, Mn, Te, Re, Fe, Ru, Os, Co, Rh , Ir, Ni, Pd, Pt, Cu, Ag, Au, Zn, Ge, Ga, In, Sn and Pb taken alone or as a mixture. Preferably, the at least one metal is selected from the group consisting of Mo, W, Re, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Sn and mixtures thereof. According to a preferred embodiment, the at least one metal is selected from the group consisting of NiSn, RePt, FePt, SnPt, CuPt, IrPt, CoPt, RhPt, OsPt, RuRe, PdRe, RuSn and RuPt, NiW.

For the purposes of the present invention, the term "catalyst" means a solid comprising the crystalline aluminum material comprising a carbonaceous deposit and also comprising an active phase, for example a metal. Thus, in this disclosure, the terms "crystalline aluminum material comprising at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals" and catalyst are synonymous and interchangeable.

Said active phase, for example a metal, may be in an oxidized or reduced form but in no case in a sulfurized form which would result from bringing said metal into contact with HIS or any other compound capable of generating H 2 S by decomposition. Said catalyst therefore does not include a phase in sulphide form. Indeed, such an active phase of the "sulfide" type shows poor performance vis-à-vis the transformation of biobased products as described in the present invention. Preferably, said active phase is in reduced form. Preferably, the total metal content belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals is advantageously between 0.1% and 30% by weight and preferably between 0.1 and 20% by weight relative to the total mass of said catalyst. When said metal is chosen from among Re, Ru, Rh, Ir, Pd, Pt, Ag and Au and mixtures thereof, the content of metal, or of each metal if there are several, is advantageously between 0.01%. and 15% by weight and preferably between 0.01 and 10% by weight relative to the total weight of said catalyst. Step a) of contacting

The invention relates to a method of preparation, and to a material prepared by a process comprising a step a) of contacting a mixture comprising at least one carbon precursor with a crystalline aluminum solid at a temperature of between 50 and 300. ° C at a pressure corresponding at least to the autogenous pressure.

Said step a) is carried out under hydrothermal conditions. That is to say that the placing in contact is carried out in an autoclave, the whole of the reaction medium then being brought to a temperature of between 50 and 300 ° C., preferably between 100 and 250 ° C. and still more preferred between 140 and 210 ° C, the pressure corresponding to at least the autogenous pressure associated with the chosen temperature. The contacting can be carried out under an oxidizing atmosphere (air), neutral (inert gas: dinitrogen, argon, etc.) or reducing, that is to say partially or completely composed of dihydrogen. In a preferred manner, the atmosphere is air.

Said carbon precursor is an organic molecule, advantageously of the sugar (glucose, fructose, sucrose, etc.) or polyol type. When said carbon precursor is a polyol, said polyol preferably contains at least 3 carbon atoms and even more preferably at least 5 carbon atoms and also preferably has at least 3 vicinal hydroxyl groups (excluding terminal hydroxyl groups) and Even more preferably, there are vicinal hydroxyl groups in the threo configuration. Useful polyols may for example be selected from the following list: xylitol, sorbitol, dulcitol. Preferably, the carbon precursor is an organic molecule of the polyol type.

The mixture comprising the carbon precursor is advantageously aqueous. It can be neutral, acidic or basic and preferably neutral. The pH of the mixture can be ensured by the addition of compounds to regulate the pH, so as to lead to an acidic mixture, basic or neutral. These compounds may belong to the following non-exhaustive list: nitric acid, hydrochloric acid, sulfuric acid, carboxylic acids, ammonia, tetraethylammonium hydroxide, urea.

Contacting a mixture comprising at least one carbon precursor with a crystalline aluminum solid results in obtaining a suspension.

The effectiveness of the carbonaceous deposit on the crystalline aluminic material prepared according to the invention is ensured by a precise control of the amount of carbon precursor introduced, the latter being essentially characterized by the mass concentration of carbon precursor in the mixture (expressed in g / 1) and by the mass ratio precursor carbonaceous / solid aluminum lens. Thus, the mass concentration of carbon precursor in the mixture is between 2 and 100 g / l, preferably between 5 and 50 g / l and more preferably between 10 and 35 g / l. Likewise, the weight ratio precursor carbon / aluminum solid in said suspension is between 0.1 and 2, preferably between 0.3 and 1 and more preferably between 0.3 and 0.6. Said suspension is advantageously autoclaved with stirring in any autoclave for imposing a specific temperature at a pressure at least equal to the autogenous pressure with stirring, at a temperature between 50 and 300 ° C, preferably between 100 and 250 ° C and even more preferably between 140 and 210 ° C.

The invention relates to a method of preparation, and a material prepared by a process comprising a step b) of heat treatment of the solid obtained at the end of step a).

Step b) of heat treatment of the solid obtained at the end of step a) is advantageously constituted by a first drying step at a temperature of between 50 and 150 ° C., in an oven for example, and then a second pyrolysis step carried out in a through-bed tubular furnace under a stream of inert gas (dinitrogen, argon, etc.) with a flow rate of between 1 and 30 ml / min / g and preferably between 5 and 15 ml / min / gsoiide and at a temperature between 300 and 1000 ° C, preferably between 400 and 700 ° C, for a period of 0.5 to 24 hours, preferably for a period of 0.5 to 12 hours and even more preferred for a period of 0.5 to 5 hours. Step c) repeating steps a) and b)

The invention relates to a method of preparation, as well as to a material prepared by a process comprising a step c) of repeating steps a) and b) until the desired deposited carbon content is obtained, that is to say to obtain a carbon content deposited on the crystalline aluminic material prepared according to the invention of between 1 and 15% by weight relative to the total mass of said material, preferably between 1 and 9% by weight and even more preferably between 1 and 7% weight.

Step c) is advantageously carried out at least once, preferably at least twice and even more preferably at least 5 times. Step d) deposition of at least one metal

The invention relates to a method of preparation, and a material prepared by a process advantageously comprising a step d) depositing at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals on the solid obtained at the end of step c).

The deposition of the at least one metal advantageously involves a precursor of said metal. For example, it can be oxide, carbide, sulfide, chloride, fluoride, iodide, bromide, nitrate, sulfate, carbonate, oxalate, acetate, phosphate, perchlorate or hydroxide of said metal. Said precursor may also be an organometallic derivative. Preferably, the precursors are selected from carbonates, organometallic complexes, metal salts such as metal chlorides and metal nitrates.

The deposition of the at least one metal according to step d) may advantageously be carried out by any technique known to those skilled in the art, such as, for example, ion exchange, dry impregnation, excessive impregnation, deposition in vapor phase, etc.

Step e) heat treatment

The invention relates to a preparation process, and a material prepared by a process advantageously comprising a step e) heat treatment of the solid obtained at the end of step d). Said step e) is advantageously carried out between 300 ° C. and 700 ° C. under an inert atmosphere.

Said step e) advantageously comprises a temperature-reducing heat treatment. The reducing heat treatment is advantageously carried out at a temperature of between 100 ° C. and 600 ° C. under a stream or under a hydrogen atmosphere.

Said reducing heat treatment can be performed "in situ", that is to say during the implementation of the material in a reaction system, prior to this implementation, or "ex situ", that is, ie before its implementation in a reaction system.

The crystalline aluminic material prepared according to the invention, or the catalyst comprising said crystalline aluminum material, can be obtained in the form of powder, beads, pellets, granules, or extrusions, the shaping operations being carried out by conventional techniques known to those skilled in the art. The formatting of the object will be a function of both the initial shaping of the crystalline aluminic material prepared according to the invention and shaping operations possibly applied to the material resulting from the preparation process according to the invention.

According to a first variant, it is also possible to perform the possible steps d) and e) of said process prior to step a), that is to say directly on the crystalline aluminum solid before it comes into contact with a mixture comprising at least one carbon precursor. The proposed new chronology then corresponds to the following steps: a ') the deposition of at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals on an aluminum solid crystalline, b ') a possible step of heat treatment of the solid obtained at the end of step a'), c ') a step of contacting a mixture comprising at least one carbon precursor with the solid obtained at the result of step a ') or b'), d) a heat treatment step of the solid obtained at the end of step c ') and e') the repetition of steps c ') and d) ') until the desired carbon content is achieved.

According to a second variant, it is also possible to deposit at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of possible internal transition metals at the same time as the carbon deposit, that is to say during step a) of said method. The proposed new chronology then corresponds to the following steps: a ") a step of contacting an aqueous mixture comprising at least one carbon precursor and at least one precursor of at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals with a crystalline aluminum solid at a temperature between 50 and 300 ° C at a pressure corresponding at least to the autogenous pressure, b ") a heat treatment step the solid obtained at the end of step a ") and c") the repetition of steps a ") and b") until the desired contents of deposited carbon and metal are obtained. The number of repetitions of steps a) and b) necessary to achieve the target concentrations of metal and carbon deposited is not necessarily identical, the simultaneous presence of the precursors metal and carbon is not necessarily required and will be adapted depending on the chosen targets in terms of final chemical composition. The present invention also relates to a process for converting a biosourced feed into compounds of interest for chemistry and petrochemistry, advantageously into mono- and poly-oxygenated compounds, using the material prepared according to the invention, or the material from the preparation process according to the invention. The biobased feedstock is a feedstock selected from the group consisting of lignocellulosic biomass, carbohydrates, sugar alcohols, and mixtures thereof. By carbohydrates is meant polysaccharides, oligosaccharides, monosaccharides, polyols and alcohols. Lignocellulosic biomass consists essentially of three natural constituents present in varying amounts according to its origin: cellulose, hemicelluloses and lignin.

Cellulose, of the general formula (CeHioO5) n, accounts for most of the 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. It is insoluble in water at ambient temperature and pressure. It can be crystalline or amorphous.

Hemicelluloses represent the second carbohydrate in quantity after the cellulose of the lignocellulosic biomass. Unlike cellulose, these polymers consist mainly of pentose monomers (5-atom rings) and hexoses (6-atom rings). Hemicelluloses are amorphous heteropolymers with a degree of polymerization lower than that of cellulose.

Lignin is an amorphous macromolecule present in varying proportions depending on the origin of the material (straw ~ 15% weight, wood: 20-26% weight). Its function is mechanical strengthening, hydrophobization and plant support. This macromolecule rich in phenolic units can be described as resulting from the combination of three monomer units of propyl-methoxy-phenol type.

Said lignocellulosic biomass advantageously comprises wood, vegetable waste, agricultural residues such as for example straw, grasses, stems, cores, or shells, logging residues such as raw materials thinning, bark, sawdust, chips, or falls, logging products, dedicated crops (short rotation coppice), residues from the agri-food industry such as residues from cotton, bamboo, sisal, banana, maize, panicum virgatum, alfalfa, coconut, or bagasse, household organic waste, waste from wood processing used wood building, pulp, paper, recycled or not.

The lignocellulosic biomass can advantageously be used in its raw form or pretreated form. The raw biomass is generally in the form of fibrous residues or powder and can advantageously be milled or shredded to allow its transport or handling.

The lignocellulosic biomass is advantageously pretreated, that is to say in a form increasing its reactivity and the accessibility of the cellulose within the biomass before its transformation. These pretreatments may be of a mechanical, thermochemical, thermomechanical and / or biochemical nature and cause the decystallization of the cellulose, a decrease in the degree of polymerization of the cellulose, the solubilization of the hemicelluloses and / or lignin and / or cellulose or partial hydrolysis of hemicelluloses 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.

By polysaccharides is meant one or more compounds containing at least 10 subunits of covalently linked osteos. The preferred polysaccharides included in said biobased feedstock are selected from starch, inulin, cellulose and hemicelluloses, alone or as a mixture.

By oligosaccharides is meant one or more compounds containing from two to ten subunits of covalently linked osteos. By oligosaccharides, is meant more particularly, on the one hand a carbohydrate having the formula (C6HIOOB) "or C6" HIO "+ P05" + / OÙ n is an integer greater than 1, obtained by partial hydrolysis of the starch , inulin, lignocellulosic biomass, cellulose and hemicelluloses, and on the other hand a so-called mixed carbohydrate having the composition (C6HioO5) m (C5H804) n, (C6mH 10m + 2O5m + 1) (C5nH8n + 2O4n + 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 hemicelluloses. They can be obtained by partial hydrolysis of starch, inulin, lignocellulosic biomass, cellulose or hemicelluloses. Oligosaccharides are generally soluble in water. The oligosaccharides included in said biosourced feed are advantageously chosen from sucrose, lactose, maltose, isomaltose, inulobiose, melibiose, gentiobiose, trehalose, cellobiose, cellotriose, cellotetraose and oligosaccharides derived from the hydrolysis of the polysaccharides named in the previous paragraph.

Monosaccharides more particularly denotes carbohydrates of general formula C _X (H20) _X or C _x H2xO _x with x an integer between 3 and 6 inclusive. Monosaccharides embedded in said biosourced feed are advantageously chosen from dihydroxyacetone (x = 3), erythrose (x = 4), xylose (x = 5), arabinose (x = 5), glucose (x = 6) , mannose (x = 6) and fructose (x = 6), taken alone or as a mixture, advantageously among xylose, fructose, glucose taken alone or as a mixture. Alcohols are chemical compounds of the formula C _n H2n + iOH. Said biosourced feed advantageously comprises an alcohol chosen from ethanol, propanol, butanol, isobutanol, pentanol, hexanol and mixtures thereof. In a preferred arrangement, said filler comprises between 1% and 99.9% by weight, preferably between 10% and 99.5% by weight, very preferably between 20% and 99% by weight and even more preferably between 30% and 98% by weight of alcohol, preferably ethanol. Said feed may also comprise impurities related, in particular, to processes for obtaining alcohol such as fermentation. The impurity content is preferably less than 10% of the weight of said filler. The alcohol or alcohols included in said feed can be of any origin, chemical, petrochemical or biosourced.

The term "polyols" denotes diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 2,3-butanediol, 1,4-butanediol, pentanediols and hexanediols. triols such as glycerol, 1,2,3-butanetriol, 1,2,4-butanetriol, pentanetriols, hexanetriols, tetrols such as erythritol, pentanetetrols, hexanetetrols.

By aldehyde, is meant for example glycolaldehyde, glyceraldehyde. By ketone is meant, for example, hydroxyacetone. Carboxylic acids and their esters are, for example, formic acid, lactic acid, alkyl formates and alkyl lactates.

The term "sugar alcohols" denotes more particularly the molecules obtained by hydrogenation of the oligosaccharide and monosaccharide sugars defined above. In the case where the alcohol sugars are obtained by hydrogenation of the oligosaccharide sugars said sugar alcohols preferably meet either the general formula C6nHion + 405n + i or C5nHsn + 404n + i where n is an integer greater than 1 or the following general formula (C6mHio _m + 205m + i) (C5nH8n + 204n + i) H2 where m and n are integers greater than or equal to 1. The alcohol sugars advantageously included in said biobased feed are selected from lactitol, maltitol, isomaltitol , inulobitol, melibitol, gentiobitol, cellobitol, cellotritol and cellotetritol and mixtures thereof.

The sugar alcohols obtained by hydrogenation of the monosaccharide sugars advantageously have the following general formula C _X (H 2 O) _X H 2 or C _x H 2 _x + 20 _x with an integer between 3 and 6 inclusive. The alcohol sugars advantageously included in said biosourced feed are chosen from glycerol (x = 3), erythritol (x = 4), xylitol (x = 5), arabinitol (x = 5), sorbitol (x = 6) and mannitol (x = 6), taken alone or as a mixture. Preferably, the alcohol sugars advantageously included in said biobased feed are chosen from cellobitol, glycerol, erythritol, xylitol, sorbitol, mannitol, taken alone or as a mixture, very preferably from xylitol, sorbitol and mannitol, taken alone or as a mixture. According to the invention, the process for converting a biobased feed into compounds of interest for chemistry and petrochemistry, advantageously into mono- and poly-oxygenated compounds, is carried out in a reaction chamber in the presence of at least one solvent, said solvent comprising water and advantageously consisting of water, under a neutral, reducing or oxidizing atmosphere, and at a temperature of between 100 ° C. and 300 ° C., and at a pressure of between 0.1 MPa and 50 MPa.

Preferably, said transformation process according to the invention operates at a temperature of between 100 ° C. and 300 ° C. and preferably between 150 ° C. and 250 ° C., and at a pressure of between 0.1 MPa and 50 MPa. and preferably between 0.5 and 30 MPa and more preferably between 0.5 and 10 MPa. Said transformation method can be operated according to different embodiments. Thus, the conversion process can advantageously be implemented batchwise or continuously, for example in a fixed bed. It can also be operated in a closed reaction chamber or in a semi-open reactor.

The material prepared according to the invention, or obtained by the preparation method according to the invention, is introduced into the reaction chamber in an amount corresponding to a mass ratio filler / material of between 1 and 1000, preferably between 1 and 500, preferably between 1 and 100, preferably between 1 and 50 and still more preferably between 1 and 25.

The material prepared according to the invention, or obtained by the preparation method according to the invention can undergo a reducing heat treatment step before the introduction of the biosourced feedstock. Said reducing heat treatment is preferably carried out at a temperature of between 100 ° C. and 600 ° C. under a stream or atmosphere of hydrogen.

If the conversion process according to the invention is operated continuously, the hourly mass velocity (biosourced feed mass flow rate / mass of material) is between 0.01 h ¹ and 5 h ^-1 , preferably between 0.02 h ¹ and 2 h ^-1 . According to the invention, the products of the reaction of the transformation process are mono- or poly-oxygenated compounds. The said mono- or polyoxygenated compounds are soluble in the water. Said mono- or polyoxygenated compounds are advantageously constituted by alcohols, polyols, aldehydes, ketones, carboxylic acids and their esters.

The reaction medium is analyzed by high pressure liquid chromatography (HPLC) using refractometry to determine the content of conversion products and by gas phase chromatography (GC).

In the case of a transformation in which the solvent is water, the quantity of the water-soluble reaction products is determined by the TOC (Total Organic Carbon) analysis, which consists of measuring the carbon in solution.

The following examples illustrate the present invention without limiting its scope. EXAMPLES

Example 1 (non-compliant)

Preparation of a composite material 9% by weight C / AhOs not according to the invention: impregnation of sucrose followed by pyrolysis (WO 2013/169391).

12.3 g of sucrose (C12H22O11) are dissolved in 16.5 ml of distilled water. The solution is then slowly impregnated with 30 g of gamma-alumina (the textural properties of which are given in Table 1). After homogenization, the mixture is placed in a closed container under a saturated water atmosphere for overnight maturation. The sample is then dried at room temperature (25 ° C) a day. The pyrolysis is carried out in a tubular furnace in a through-bed under a stream of nitrogen of 10 ml / min / g of solid. The pyrolysis temperature is set at 600 ° C. It is reached with a ramp of 5 ° C / min and is maintained for 1 hour.

The recovered solid is characterized by nitrogen volumetry. The nitrogen adsorption shows that the prepared material is mesoporous with a specific surface area of 194 m ² / g, a pore diameter of 8.5 nm and a pore volume of 0.40 ml / g. For this synthesis, the carbon content is 9% by weight relative to the total mass of the sample. The data are shown in Table 1. The corresponding sample is called C / Al 2 O 3 imp.

Example 2 (compliant)

Synthesis of a composite material 7% weight C / Al2O3 according to the invention.

7.5 g of sorbitol (C6H14O6) and 15 g of gamma alumina (mass ratio sorbitol / Αΐ2θ ^" 3 = 0.5) are mixed with 100 ml of distilled water in an autoclave equipped with a mechanical paddle stirrer. The The system is hermetically sealed and is heated to 200 ° C. with a ramp of 8 ° C./min with mechanical stirring of 300 rpm. The temperature is maintained for 10 h and then the solid is recovered by centrifugation of the solution at 13000 rpm. After washing with distilled water, the solid is dried in an oven at 100 ° C. for 10 h and then pyrolyzed at 600 ° C. for 1 hour in a through-flow tubular oven under a flow of nitrogen of 10 ml / min. g with a temperature ramp of 5 ° C / min. The sample is then recovered and the entire process is repeated identically 7 consecutive times. During the preparations, the sorbitol / composite mass ratio is maintained at 0.5 and the volume of distilled water is maintained at 100 ml for each repetition.

The final sample as well as some intermediate samples are characterized by nitrogen volumetry. The data are shown in Table 1. The corresponding sample is called C / Al2O3 ads.

Hydrothermal stability test

0.5 g of solid are added to 100 ml of distilled water in an autoclave equipped with a mechanical paddle stirrer. The system is sealed and the temperature is raised to 200 ° C and maintained for 10 hours with stirring at 350 rpm. The solid is recovered by centrifugation at 13000 rpm and is then dried in an oven at 100 ° C. for 10 h.

The sample is then characterized by nitrogen volumetric and X-ray Diffraction (XRD).

Table 1: textural properties, carbon mass content and mass content of boehmite before and after HT treatment of the reference alumina and carbon samples on alumina prepared according to Examples 1 and 2.

 AlOOH after

Content C SBET Dp Vp

 Sample HT treatment

(wt%) (m ² / g) (nm) (ml / g)

 (% weight)

Before AI2O3 0 212 8.8 0.55 0 treatment C / AI2O3 imp 9 194 8.5 0.40 0 hydrothermal C / Al2O3 ads 7 185 6.5 0.33 0

After Al2O3 HT 0 40 33.2 0.32 100 treatment C / AhOa imp HT 7 124 20.5 0.33 95 hydrothermal C / Al2O3 ads HT 8 198 6.5 0.32 12 Example 3

Preparation of catalysts C1, C2, C3, C4

Catalysts C1 and C2 are prepared by impregnating "C / AkC ads" and "Al2O3" supports with a solution of hexachloroplatinic acid. The target Pt metal mass content is 0.5% based on the weight of the catalyst. After impregnation, the catalysts are dried for 24 hours at 120 ° C. and then calcined for 4 hours. The catalysts are then reduced under hydrogen flow at 350 ° C for two hours.

Catalysts C3 and C4 are prepared by impregnation of the supports "C / Al2O3 ads" and "Al2O3" with an aqueous solution of nickel nitrate Ni (NO3) 2.6H2O. The mixture is stirred for one hour and then evaporated. The solids obtained are then dried in an oven at 110 ° C. for 24 hours. The solids are calcined and reduced under a stream of hydrogen C for two hours. The catalysts C3 Ni (10%) / C / Al2O3 ads and C4 Ni (10%) / C / Al ₂ O ₃ are thus obtained.

Example 4

Transformation of cellulose using catalysts C1, C2, C3, C4 This example relates to the conversion of cellulose from a combination of a catalyst described in Example 3 and a metal salt or H2WO4 for the production of mono- and polyoxygenated products.

In a 100 ml autoclave, 50 ml of water, 1.5 g of SigmaCell® cellulose, 0.03 g of cerium chloride or of H2WO4 and the catalyst are introduced under a nitrogen atmosphere. A pressure PH2 is introduced then the autoclave is heated to a temperature Treactkm. After 12 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 spent catalysts are taken centrifuged and analyzed by XRD. The results obtained are referenced in Table 2. Table 2: solubilization of cellulose

 The catalysts C1 and C3 according to the invention are active for the conversion of cellulose with solubilization rates of 72% and 91%. The yields of ethylene glycol (EG) and propylene glycol (PG) diols of the catalysts are higher than those of catalysts prepared with oxide supports.

The catalysts according to the invention are more stable after catalytic tests than the non-compliant C2 and C4 catalysts with a boehmite quantity generated by the lower hydrothermal conditions.

Claims

A crystalline aluminum material comprising a carbonaceous deposit, the deposited carbon content being between 1 and 15% by weight of the total mass of the material, prepared by a process comprising at least: a) a step of contacting a mixture comprising at least one carbon precursor with a crystalline aluminum solid at a temperature of between 50 and 300 ° C. at a pressure corresponding at least to the autogenous pressure, the concentration of carbon precursor in said mixture being between 2 and 100 g / 1, the weight ratio precursor carbon / aluminum solid in the suspension consisting of said mixture and the crystalline aluminum solid being between 0.1 and 2; b) a heat treatment step of the solid obtained at the end of step a); c) repeating steps a) and b) until the desired deposited carbon content is achieved. Material according to one of the preceding claims wherein the carbon content deposited is between 1 and 9% by weight relative to the total mass of the material. Material according to one of the preceding claims prepared by a process also comprising a step d) depositing at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the transition metal family internal on the solid obtained at the end of step c). Material according to the preceding claim prepared by a process also comprising a step e) of heat treatment of the solid obtained at the end of step d). Material according to claim 3 or 4 wherein the metal content belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals is between 0.1% and 30% by weight. the total mass of said catalyst. 6. Preparation process comprising at least:  a) a step of contacting a mixture comprising at least one carbon precursor with a crystalline aluminum solid at a temperature of between 50 and 300 ° C. at a pressure corresponding at least to the autogenous pressure, the concentration of carbon precursor in said mixture being between 2 and 100 g / 1, the weight ratio precursor carbon / aluminum solid in the suspension consisting of said mixture and the crystalline aluminum solid being between 0.1 and 2;  b) a heat treatment step of the solid obtained at the end of step a);  c) repeating steps a) and b) until the desired deposited carbon content is achieved. 7. The method of claim 6 wherein said step b) consists of a first step of drying at a temperature between 50 and 150 ° C, and a second pyrolysis step carried out in tubular furnace bed traversing under a flow of inert gas with a flow rate of between 1 and 30 ml / min / gsoiide and at a temperature between 300 and 1000 ° C for a period of 0.5 to 24 hours. 8. Method according to the preceding claim comprising a step d) depositing at least one metal belonging to columns 4 to 14 of the periodic table according to the IUPAC classification or to the family of internal transition metals on the solid obtained at the outcome of step c). 9. Method according to the preceding claim comprising a step e) heat treatment of the solid obtained at the end of step d). The method of claim 8 comprising a step e) comprising a reducing heat treatment. 11. A process for converting a biosourced feed into mono- and poly-oxygenated compounds using a catalyst according to one of claims 3 to 4 in a reaction chamber in the presence of at least one solvent, said solvent containing water, under a neutral atmosphere, reducing or oxidizing, and at a temperature between 100 ° C and 300 ° C, and at a pressure between 0.1 MPa and 50 MPa, the mass ratio filler / material being between 1 and 1,000.