FR3008970A1 - PROCESS FOR THE PRODUCTION OF ALCOHOLS BY CATALYTIC HYDROGENATION OF LEVULINIC ACID IN ONE STEP - Google Patents

Abstract

The invention relates to a process for converting a feedstock comprising levulinic acid to monoalcohol in the presence of hydrogen, said process operating in one step, at a temperature of between 80 ° C and 250 ° C, at a pressure of between 0.5 and 20 MPa, and in the presence of a catalyst comprising a metal of groups 7 to 10 selected from platinum (Pt), ruthenium (Ru), iridium (Ir), rhenium ( Re), said metal being used alone and a support selected from titanium oxide (TiO2), zirconium oxide (ZrO2), and silica (SiO2), alone or in admixture. The process according to the invention makes it possible in particular to obtain butanol and preferably 2-butanol at a selectivity greater than 15 mol%,

Description

FIELD OF THE INVENTION The present invention relates to a one-step process for the transformation of a feedstock comprising levulinic acid, which is advantageously obtained from the treatment of alcoholic acid. biomass, monoalcohol, preferably butanol and in particular 2-butanol. Prior art In recent years, environmental concerns and increased fossil fuel costs have stimulated worldwide interest in the development of alternatives to petroleum products, chemicals and other products. There is therefore a keen interest in incorporating renewable products into the fuel and chemical sectors, in addition to or in substitution for products of fossil origin. 15 The US Department of Energy (DOE) recently compiled the set of value-added chemicals that can be produced from "saccharide" biomass (Green Chem 12, 539-554 (2010)). highlighted 10 main synthons produced from sugar including levulinic acid (LEV) or 4-oxopentanoic acid Levulinic acid is the product of reactions of acid degradations of starch or cellulosic part of biomass lignocellulosic: Levulinic acid (LEV) is the final product obtained by the acid treatment of glucose, by isomerization and acid dehydration levulinic acid is converted to 5-hydroxymethylfurfural (HMF). HMF induces a break in the cycle to simultaneously form a molecule of levulinic acid and formic acid, so that levulinic acid can be considered as the major product of controlled hexose transformation. The theoretical theoretical yield from glucose is 64.5% (water and formic acid production). The transformation and recovery of levulinic acid (LEV) in the aqueous phase, potentially in the presence of formic acid, into high value-added petrochemical products is therefore of great interest. (Fig. 1) Levulinic acid is therefore recognized as one of the most widely available "platform" molecules from carbohydrates. This molecule has two different reactive functional groups (-C = 0 and -COOH) which allows many possibilities of transformations.

In the literature, for example, there are catalytic hydrogenation transformations which make it possible to obtain various compounds having various applications: gammavalterolactone (GVL), methyl tetrahydrofuran (MTHF), 1,4-pentanediol (1,4-PDO). (Figure 2) (Manzer, The Feedstocks for the Future, pp. 40-51 (American Chemical Society, 2006) Bozell, JJ et al., Production of levulinic acid and its use as a platform for chemical products. and Recycling, 28, 227-239 (2000), Serrano-Ruiz, JC, Dumesic, JA & West, RM Catalytic Conversion of Renewable Biomass Resources to Fuels and Chemicals, Chemical and Biomolecular) In general, the catalytic hydrogenation of Carboxylic acids require severe reaction conditions of temperature and pressure in the liquid phase, in the presence of mono or bimetallic catalysts, rather based on noble metals.

The hydrogenation of levulinic acid can lead under certain conditions to the production of gamma-valerolactone (GVL). The patent application US2003 / 0055270 describes a process for the selective production of gammalterolactone (GVL) from levulinic acid, by heating in the presence of hydrogen and of a catalyst having both a hydrogenating function and a function allowing the closure of a cycle, wherein said catalyst is a metal, optionally supported. The preferred solvent is dioxane. The metal is advantageously chosen from the elements of groups 7 to 10 of the periodic table and preferably from iridium (Ir), palladium (Pd), platinum (Pt) and rhenium (Re). ), rhodium (Rh), ruthenium (Ru) alone or in admixture and very preferably the metal is ruthenium (Ru). In the case where said catalyst is supported, the support is advantageously selected from carbon, silica (SiO 2) and alumina (Al 2 O 3). Said catalyst can optionally be promoted by an element chosen from the elements of Groups 8-10 and Group 11 and preferably gold, silver and copper.

Said method for selective production of gamma-valerolactone (GVL) operates at a temperature between 100 and 200 ° C, at a pressure of between 0.5 and 10 MPa and in the liquid phase. It is stated in the application that the hydrogenation and ring closure reaction operates in one step and produces little or no pentyl alcohol such as pentanediol.

In US2003 / 0055270, Manzer et al. observe that the most selective gamma-valerolactone (GVL) catalysts which make it possible to obtain a quasi-quantitative conversion of levulinic acid (in solution 50% by weight levulinic acid / dioxane) are the catalysts Ru / C, Rh / C, Ir / C implemented in a process operating at a pressure P (H2) of between 0.45 and 0.55 MPa, at a temperature of 215 ° C., and for a period of 2 hours. The patent application does not mention the production of monoalcohol and in particular butanol. Lange et al. (R. Haan and J.-P. Lange) described in the patent application WO / 2011/015645 2011. and in the publication J-P. Lange et al., (Angew Chem., 122, 2010, 4581-4585.) The hydrogenation of levulinic acid to selectively produce gamma valerolactone (GVL) through the use of a catalyst comprising at least one metal supported on TiO2 or ZrO2, said catalyst being more resistant to poisoning, more stable, more active and more selective than the hydrogenation catalysts described in the prior art and in particular the catalysts supported on SiO2 or C. The metal of the The catalyst is advantageously chosen from metals of groups 7, 8 to 10 and 11 and preferably from iridium (Ir), palladium (Pd), platinum (Pt), Rhenium (Re) and Rhodium (Rh). , Ruthenium (Ru), Osmium (Os), and Gold (Au), alone or as a mixture, the content of metal or metals being between 0.05 and 5% by weight relative to the total mass of said catalyst. The process for the selective transformation of levulinic acid into gamma-valerolactone (GVL) is advantageously carried out at a temperature of between 50 and 350 ° C., at a pressure of between 0.1 and 10 MPa, in the liquid phase and at a weight speed. hour whsv (weight hour space velocity) 0.1 and 30 g levulinic acid / g catalyst / h. The examples of the patent application WO / 2011/015645 explicitly describe the hydrogenation of a concentrated aqueous solution of levulinic acid (89% by weight) in GVL in a continuous reactor in the presence of monometallic catalysts (Pd, Pt) or bimetallic compounds (Pt-Re, Pt-Au and Pt-Ir) supported on TiO2 or ZrO2. The catalysts supported on TiO 2 or ZrO 2 were found to be more active than conventional hydrogenation catalysts supported on SiO 2 or C. The catalyst 0.5% by weight Re-0.5% by weight Pt / TiO 2 shows a very good GVL selectivity but exhibits a tendency to deactivation. The patent application does not mention the production of monoalcohol and in particular butanol. Recently, Al-Shaal et al. studied the influence of different solvents (alcohols, water, water-alcohol mixture) on the hydrogenation of a levulinic acid solution (5% by weight) in gamma-valerolactone (GVL) in the presence of Ru / C catalysts Ru / TiO 2, Ru / SiO 2 and Ru / Al 2 O 3 (Green Chem 14, 2012, 1260-1263). The results show that levulinic acid is converted to gamma-valerolactone (GVL) with 70% selectivity and 80% conversion in the presence of Ru / TiO 2 catalyst in a EtOH / H 2 O solvent mixture: 10, at a temperature of 130 ° C, a pressure P (H2) = 1.2 MPa, and during a reaction time t = 160min. The patent application WO2010 / 129147 describes the production of 2-butanol from levulinic acid according to a process of transformation into two distinct steps. The first step is a decarboxylation of levulinic acid to ethyl methyl ketone (2-butanone) operated in the absence of hydrogen in the presence of a catalyst of Cu / zeolite type. The second step is a catalytic hydrogenation of ethyl methyl ketone to reduce the intermediate ethyl-methyl ketone compound (2-butanone) to 2-butanol, in the presence of a conventional hydrogenation catalyst such as a catalyst based on nickel or ruthenium. The patent application WO2010 / 129147 does not disclose a process for converting a feed containing levulinic acid leading to the selective formation of 2-butanol in a single step by catalytic hydrogenation in the presence of a single specific catalyst. US5883266 discloses a process for the preparation from levulinic acid of a hydrogenated product comprising, alone or as a mixture, 2-methyltetrahydrofuran (MTHF), gamma-valerolactone (GVL), pentanediol, in the presence of a bifunctional catalyst having both a hydrogenating function and a function for opening the ring. The bifunctional catalyst may be a mono-metallic or bimetallic catalyst, preferably supported. The hydrogenating function is provided by a first metal selected from copper (Cu), nickel (Ni), and metals selected from iridium (Ir), palladium (Pd), platinum (Pt), rhenium ( Re), rhodium (Rh), ruthenium (Ru), osmium (Os), alone or in admixture, and preferably the first metal is palladium (Pd). The function for opening the cycle is provided by a second metal which may be the same or different from the first. The second metal is selected from rhenium (Re), ruthenium (Ru), copper (Cu), nickel (Ni), tin (Sn), cobalt (Co), manganese (Mn), iron (Fe), chromium (Cr), molybdenum (Mo) and tungsten (W), alone or as a mixture, and preferably the second metal is rhenium (Re). The support is advantageously chosen from metal oxides having a high specific surface and preferably from carbon, alumina (Al 2 O 3), titanium oxide (TiO 2), zirconium oxide (ZrO 2), silicate magnesium (MgSiO2), alone or in admixture. TiO2 and ZrO2 supports are mentioned but not exemplified. Only the carbon support is illustrated. A preferred catalyst is a catalyst comprising 0.5 to 10% by weight of palladium (Pd) and 1 to 12% by weight of rhenium (Re) deposited on a carbon support.

The process according to the patent US5883266 operates at a temperature between 100 and 300 ° C and a hydrogen partial pressure greater than 1 MPa. Said process allows the production of a hydrogenated product comprising a molar concentration or a selectivity of 2-methyltetrahydrofuran (MTHF) greater than 25%, preferably greater than 50% and preferably greater than 75% but also by-products. such as alcohols and in particular a molar concentration or a selectivity of 1-pentanol of between 1 and 25%, of 2-pentanol of between 0.05 and 2% and of 2-butanol of between 0.05 and 5%. The hydrogenated product also includes intermediates such as gamma valerolactone (GVL) at a molar concentration between 0.1 and 60% and pentanediol at a molar concentration of between 0.01 and 20%. Thus, there is currently no process for converting a feed containing levulinic acid leading to the selective formation of monoalcohol and in particular butanol in one step by catalytic hydrogenation with a single catalyst. The conversion of levulinic acid resulting from the conversion of biomass, especially to butanol, is a particularly advantageous route because this product can for example be incorporated into the gasoline pool, or be used directly or after transformation into a chemical or petrochemical intermediate ( butenes, butadiene ...). The Applicant's work has made it possible to demonstrate, surprisingly, the use of a catalyst characterized by the combination of a specific active phase deposited on a specific support in a process for transforming a feedstock comprising the levulinic acid and operating under specific operating conditions allowed the selective production, in one step, of mono-alcohol and in particular of 2-butanol while minimizing the production of secondary product such as 2-methyltetrahydrofuran (MTHF) or intermediate product such as gamma-valerolactone (GVL). SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a process for converting a feedstock comprising levulinic acid to monoalcohol in the presence of hydrogen, said process operating in one step at a between 80 ° C and 250 ° C, at a pressure of between 0.5 and 20 MPa, and in the presence of a catalyst comprising a metal of groups 7 to 10 selected from platinum (Pt), ruthenium ( Ru), iridium (Ir), rhenium (Re), said metal being used alone and a support selected from titanium oxide (TiO2), zirconium oxide (ZrO2), and silica (SiO2) , taken alone or in a mixture. Surprisingly, it has been discovered that when a catalyst exhibiting the specific combination of the above mentioned characteristics is used under the operating conditions indicated above, it makes it possible to carry out a significant conversion of levulinic acid and selectively produce 2-butanol. An advantage of the present invention is therefore to provide a process for converting a feed comprising levulinic acid to monoalcohol, preferably butanol and particularly 2-butanol, having a high conversion of the acid. levulinic. The process according to the invention makes it possible in particular to obtain butanol and preferably 2-butanol at a selectivity greater than 15 mol%, preferably 20 mol%, highly preferred 25%. The advantage of the process according to the present invention is therefore to selectively produce 2-butanol from a levulinic acid-rich feedstock. DETAILED DESCRIPTION OF THE INVENTION The invention relates to a process for the conversion of a feedstock comprising levulinic acid to monoalcohol in the presence of hydrogen, said process operating in one step at a temperature of between 80.degree. C and 250 ° C, at a pressure between 0.5 and 20 MPa, and in the presence of a catalyst comprising a metal of groups 7 to 10 selected from platinum (Pt), ruthenium (Ru), iridium (Ir), rhenium (Re), said metal being used alone and a support selected from titanium oxide (TiO 2), zirconium oxide (ZrO 2), and silica (SiO 2), taken alone or in mixed. 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. The filler According to the invention, the filler used comprises at least levulinic acid. The filler may also advantageously comprise one or more acids. Said filler may also advantageously comprise one or more degradation products related to the process for obtaining levulinic acid, in particular when the levulinic acid is obtained from lignocellulosic biomass. By way of example, the filler may contain formic acid, 5-hydroxymethylfurfural, sugars such as glucose, xylose, furfural, phenolic fragments derived from partial lignin decomposition, humins or polyoxygenated compounds of masses. important molecules, mineral impurities. Preferably, said charge does not include alcohols. Preferably, said filler 5 does not include other organic derivatives. Preferably, the process according to the present invention is a process for converting in a aqueous medium a feedstock comprising levulinic acid. Preferably, said filler comprises water at a content of between 1% and 99% by weight relative to the total weight of the filler, preferably between 30% and 99% by weight and preferably between 40% and 98% by weight. weight relative to the weight of the load. The levulinic acid content in said filler is advantageously between 1% and 99% by weight, preferably between 1% and 70% by weight, and preferably between 2% and 60% by weight relative to the total weight of the filler. The levulinic acid contained in said feedstock is preferably of biobased origin. It can advantageously be produced, for example, by transformation of sugar plants such as sugar beet or sugar cane, by transformation of starch plants such as wheat, maize, potato, cassava or by transformation of lignocellulosic biomass. The lignocellulosic raw material may advantageously be wood or vegetable waste. Other non-limiting examples of lignocellulosic biomass material are farm residues (straw, grass, stems, cores, shells, etc.), logging residues (first-thinning products, bark, sawdust, chips, falls ...), logging products, dedicated crops (short-rotation coppice), residues 25 from the agri-food industry (residue of the cotton industry, bamboo, sisal, banana, maize, panicum virgatum, coconut, bagasse ...), household organic waste, waste wood processing facilities, used wood building, paper, recycled or not. The production of levulinic acid from sugar plants or starchy plants involves steps of acidic transformation (hydrolysis, isomerization, hydration / dehydration). On the other hand, obtaining levulinic acid from raw lignocellulosic biomasses is more complex and requires several steps, simultaneous or successive, namely: a pretreatment of the lignocellulosic biomass, a hydrolysis of the carbohydrate part (cellulose and hemicellulose) and - an acid catalyzed reaction of levulinic acid production of the monomeric sugars obtained after hydrolysis. The lignocellulosic biomass feedstock 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. In general, it is crushed or shredded to allow its transport. 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, the solubilization of hemicellulose and / or lignin or the partial hydrolysis of the hemicellulose according to treatment. The lignocellulosic biomass feed may also be pretreated to be in the form of water-soluble oligomers. These pretreatments are of a mechanical, thermochemical, thermomechanical-chemical and / or biochemical nature. They cause decystallinization and solubilization of cellulose in the form of water-soluble oligomers. The hydrolysis step may be carried out by any of the techniques known to those skilled in the art, such as for example by homogeneous or heterogeneous acid catalysis or by enzymatic catalysis. The production of levulinic acid from sugars is advantageously carried out by acid catalysis, for example in the presence of sulfuric acid. Preferably, the feedstock treated in the process according to the invention is derived from the acid treatment of the biomass. Said filler advantageously comprises, in addition to levulinic acid, formic acid, traces of sulfuric acid and organic and inorganic impurities. The catalyst According to the invention, the catalyst used comprises and preferably consists of a metal of groups 7 to 10 selected from platinum (Pt), ruthenium (Ru), iridium (Ir), rhenium (Re ), said metal being used alone and a support selected from titanium oxide (TiO2), zirconium oxide (ZrO2), and silica (SiO2), alone or in admixture. According to a preferred embodiment, the catalyst used has the above definition, with the exception of the catalyst comprising and preferably consisting of a noble metal, said noble metal being ruthenium (Ru) and a silica support (SiO2). According to another preferred embodiment, the catalyst used has the above definition, with the exception of the catalyst comprising and preferably consisting of a noble metal, said noble metal being platinum (Pt) and a titanium oxide support (TiO 2 ).

Preferably, said metal is chosen from the noble metals of groups 7 to 10 and preferably from platinum (Pt) and ruthenium (Ru), said metal being used alone and very preferably, the metal is ruthenium ( Ru) used alone. Preferably, said catalyst used in the present invention does not contain a doping element. Preferably, said catalyst comprises a metal content of groups 7 to 10 of between 0.1 and 10% by weight and preferably between 0.2 and 8% by weight relative to the total weight of said catalyst. Preferably, said support is selected from titanium oxide (TiO 2) and zirconium oxide (ZrO 2), taken alone or in a mixture and very preferably, said support is titanium oxide (TiO 2). A preferred catalyst used in the process according to the invention is ruthenium alone and a support selected from titanium oxide or zirconium oxide alone or in admixture. A very preferred catalyst used in the process according to the invention consists of ruthenium alone and a titanium oxide support. The catalyst support used in the present invention preferably has a BET surface area of between 5 and 400 m 2 / g and preferably between 10 and 350 m 2 / g and a pore volume of between 0.1 to 2.0 ml / g and preferably between 0.15 and 1.5 ml / g. The catalyst of the invention may be prepared according to any of the techniques known to those skilled in the art: dry impregnation (s), excess impregnation (s), ion exchange (s), deposition / precipitation, deposition (s) in the precursor vapor phase containing ruthenium on the support selected from titanium oxide or zirconium oxide alone or as a mixture. The ruthenium precursors may be selected from ruthenium oxides, ruthenium halides, such as ruthenium chlorides, ruthenium iodides, ruthenium bromides, ruthenium sulfides, ruthenium carbides, ruthenium fluorides , ruthenium oxychlorides, ruthenium nitrates, ruthenium-based organic derivatives such as ruthenium acetylacetonate, and Ru (NH3) 6C12 aminochlorinated precursors.

The platinum precursors can be chosen from metal organic complexes such as platinum acetylacetonate Pt (C611702) 2, platinum complexes dichloro (ethylenediamine) (H2NCH2CH2NH2) PtCl2, platinum oxides PtO, PtO2, metal salts such as chlorides platinum PtC12, PtC14, hexachloroplatinic acid H2PtC16, potassium hexachloroplatinate K2PtC16, potassium tetrachloraplatinate K2PtC14, ammonium tetrachloraplatinate (NH4) 2PtC14, ammonium hexachloroplatinate (NH4) 2PtC14, metal nitrates. Pt (NH3) 2 (NO2) PtBr2 platinum bromides. The rhenium precursors may be chosen from Rhenium oxides Re207, ReO3, ReO2, rhenium salts such as rhenium chlorides, ReCl3, ReCl5, Rhenium iodides Re13, ammonium perrhenate NH4ReO4, hexachlororhenate from potassium K2 ReC16. The iridium precursors can be chosen from metal organic complexes such as iridium acetylacetonate Ir [C6H702) 3, iridium oxides 1rO2, iridium salts such as iridium chlorides lrCl3, PtC14, hexachloroiridate of K2PtC16 potassium, ammonium hexachloroiridate (NH4) 2IrC16. Titanium oxide (TiO2) is advantageously prepared according to any technique known to those skilled in the art such as, for example, titanium chloride hydrolysis, hydrolysis / condensation of titanium alkoxide solutions and the like. (Handbook of Porous Solids, Schüth, Wiley-VCH Edition, Volume 3). The titanium oxide used in the present invention may be in crystallographic rutile, anatase, brookite pure form or in admixture. The zirconium oxide (ZrO 2) is advantageously prepared according to any technique of the skilled person such as, for example, hydrolysis of zirconyl chloride, hydrolysis / condensation of solutions of zirconium alkoxides and the like. (Handbook of Porous Solids, Schüth, Wiley-VCH Edition, Volume 3). The zirconium oxide used in the present invention may be in amorphous, tetragonal, pure monoclinic crystalline form or in admixture. The silicon dioxide SiO 2 is advantageously prepared according to any technique of the skilled person. There are several types of silica: colloidal silica, precipitated silica prepared for example by acidification of sodium silicates, silica gel etc. (Handbook of Porous Solids, Schüth, Wiley-VCH Edition, Volume 3). The silicon oxide used in the present invention may be in amorphous or crystallized crystallographic form. After introduction of the group 7 to 10 metal onto the support chosen from titanium oxide (TiO 2), zirconium oxide (ZrO 2), and silica (SiO 2), taken alone or as a mixture, and before it is applied. In the conversion process according to the invention, the catalyst can advantageously be subjected to a heat treatment step. The heat treatment is advantageously carried out at a temperature of between 150 ° C. and 500 ° C. and preferably between 150 ° C. and 400 ° C. The duration of the heat treatment is advantageously between 0.5 h and 10 h. The heat treatment step may advantageously be followed by a temperature reduction treatment. The reducing heat treatment is advantageously carried out at a temperature of between 100 ° C. and 600 ° C. under a stream or atmosphere of hydrogen. The reduction period is advantageously between 0.5 h and 10 h. The reduction step can advantageously be carried out in situ, that is to say in the reactor where the reaction takes place, before the introduction of the reaction charge. The reduction can also be performed ex situ. After introduction of the group 7 to 10 metal onto the support chosen from titanium oxide (TiO 2), zirconium oxide (ZrO 2), and silica (SiO 2), taken alone or as a mixture, and before it is applied. In the conversion process according to the invention, the catalyst can advantageously be reduced in the liquid phase. The volume of the aqueous catalyst reduction solution is advantageously between 1 and 20 times the volume of catalyst engaged. The reducing agent used is advantageously chosen from formic acid, citric acid, ascorbic acid, oxalic acid, sodium formate, sodium acetate, sodium borohydride, formaldehyde and dextrose. , hydrazine, hydrogen or any other conventional liquid phase reductant. The molar ratio reducing agent / ruthenium is preferably between 1 and 50, preferably 2 and 40. The preparation temperature is preferably between -5 ° C and 70 ° C, and preferably between 5 ° C and 60 ° C. ° C. The residence time of said aqueous solution in the apparatus is between 0 and 20 h. The liquid phase reduction step can be preceded by a drying step in order to eliminate all or part of the water introduced during the impregnation, preferably at a temperature of between 50 ° C. and 250 ° C. more preferably between 70 ° C and 200 ° C. The drying time is generally between 0.5 h and 20h. The drying is generally carried out under air, at atmospheric pressure or under partial vacuum.

The reduction step in the liquid phase may be preceded by a drying step and a calcination step, generally carried out under air at a calcination temperature, is generally between 150 ° C. and 500 ° C., preferably between about 150 ° C and about 450 ° C. The calcination time is generally between 0.5 h and 10 h.

During the preparation of the catalysts according to the invention, the support may be in the form of powder or shaped, for example in the form of beads or extrudates or pellets or any other form commonly used. The shaping can be carried out before or after the introduction of ruthenium.

The catalysts used in the present invention are characterized by techniques known to those skilled in the art, such as X-ray fluorescence, nitrogen adsorption-desorption, transmission electron microscopy, X-ray diffraction. the present invention preferably has a surface area of between 5 and 400 m 2 / g and preferably between 10 and 350 m 2 / g and a pore volume of between 0.1 to 2.0 ml / g and preferably between 0.15 and and 1.5 mL / g. In accordance with the invention, said process for converting a feedstock comprising levulinic acid into monoalcohols according to the invention operates in the presence of hydrogen. The hydrogen may advantageously be used pure or as a mixture. The amount of hydrogen introduced is such that the hydrogen / levulinic acid molar ratio is advantageously between 1 and 4000 mol / mol. According to the invention, said process is advantageously carried out in a single step, with the hydrogen pressure being maintained throughout the reaction stage, without any intermediate separation along the reactor. According to the invention, said process preferably operates at a temperature of between 80 ° C and 250 ° C, preferably between 85 ° C and 240 ° C, very preferably between 90 ° C and 230 ° C and more preferably between 100 and 200 ° C and at a total pressure of between 0.5 MPa and 20 MPa, preferably between 1 MPa and 20 MPa, very preferably between 2 MPa and 20 MPa. The reaction can advantageously be carried out in a closed reactor or continuously (fixed bed technology, slurry, trickle bed).

If the reaction is carried out continuously, for example in a fixed bed, the hourly mass velocity (levulinic acid flow / mass of catalyst) is between 0.01 and 10 h -1, preferably between 0.01 and 5 h -1. and very preferably between 0.05 and 2 h -1.

If the reaction is operated in batch mode, the reaction time is between 10 and 50 hours, preferably between 12 and 40 hours. The mass ratio of levulinic acid relative to the catalyst mass is between 0.1 and 500, preferably between 0.1 and 250 and very preferably between 0.5 and 100.

The advantage of the process according to the present invention is therefore to selectively produce butanol and preferably 2-butanol from a levulinic acid-rich feedstock. The process according to the invention makes it possible in particular to obtain butanol and preferably 2-butanol in a selectivity of greater than 15 mol%, preferably 20 mol%, highly preferred 25%.

The process according to the present invention also leads to the formation of other products: gamma valerolactone (GVL), 1,4 pentanediol (PDO), methyl tetrahydrofuran (MTHF) and angelica lactone (AGL). 2-butanone is not observed as a reaction product. The effluent from the process according to the invention contains a content of 2-butanone of less than 1 mol%. There is also the presence of light gases such as, for example, carbon monoxide, carbon dioxide, light alkanes such as methane, ethane, propane, butane and light alkenes. The amount of light gases is generally between 0.1 mol% and 50 mol%.

The presence of pentanoic acid, pentanol, 2-pentanol, propanol, methanol and isopropanol is also observed. The method according to the invention makes it possible to obtain a gamma-valerolactone (GVL) selectivity advantageously less than 20 mol%, preferably less than 15%, very preferably less than 12%, and even more preferably less than 5%. The process according to the invention makes it possible to obtain a pentanediol selectivity (PDO) advantageously less than 50 mol%, and preferably less than 45%.

The method according to the invention also makes it possible to obtain a selectivity for methyltetrahydrofuran (MTHF) advantageously less than 15 mol%, preferably less than 10%, very preferably less than 5%.

DESCRIPTION OF THE FIGURES FIG. 1 illustrates the chemical reactions allowing the production of levulinic acid by acid hydrolysis of the biomass. FIG. 2 illustrates the chemical reactions allowing the selective conversion of levulinic acid by heterogeneous catalysis in the aqueous phase to 2 butanol. The examples below illustrate the invention without limiting its scope. EXAMPLES Example 1: Preparation of catalyst C1 (according to the invention): 1.6 ° / Ru / TiO 2 opoids In a three-necked flask of 500 mL, equipped with mechanical stirring and a water cooler, is added 5 g of TiO2 titanium oxide support of anatase structure (SBET = 95 m 2 / g) suspended in 70 ml of ultrapure water. An aqueous solution containing the metal precursor is prepared from 20 ml of ultrapure water and 0.2083 g of RuCl.sub.3 and then added dropwise to the solution containing the support. The pH of the solution is adjusted to 11 and then the reaction medium is then heated at 100 ° C. for 1 hour. After cooling to room temperature, the solid is filtered and washed several times until the filtrate is neutral. The solid is then placed in an oven overnight to be dried (60 ° C, 50-100 mbar). The catalyst C1 obtained is then reduced under a stream of hydrogen for 3 h at 300 ° C. When the cell has returned to room temperature, the catalyst is purged with argon then passivated by a flow of 1% O 2 / N 2. Catalyst C1 contains 1.6% by weight of ruthenium. XRD analysis of the catalyst did not reveal Ru diffraction peaks. EXAMPLE 2 Preparation of Catalyst C2: 2.6% Ru Weight / T102 In a 500 mL three-necked flask, 10 g of an anatase titanium oxide support TiO2 (SBET = 95 m 2 / g) are suspended in 100 mL of ultra pure water at room temperature under nitrogen flow. A 15 ml aqueous solution containing the metal precursor 0.7022 g of RuCl3 is added dropwise. Stirring of the reaction medium then continues for 5 hours. Then the temperature is set at 0 ° C by the use of an ice bath. A reduction is then made in situ in the liquid phase. 50 ml of formaldehyde (37% by weight in water) are added dropwise over 20 min. After waiting 10 minutes, 20 ml of a solution of KOH (30% by weight) are added dropwise. The catalyst is then filtered and washed until neutrality of the filtrate. The catalyst is then dried in an oven under vacuum overnight (60 ° C, 50-100 mbar). The catalyst obtained then contains 2.6% by weight of ruthenium. XRD analysis of the catalyst did not reveal Ru diffraction peaks. EXAMPLE 3 Preparation of a Catalyst C3 (not in Accordance with the Invention) 1.5% by Weight Ru / C In a three-necked flask of 500 ml equipped with a mechanical stirrer and a water cooler, add 5 g of the activated carbon support (SBET = 900 m2 / g) in suspension in 70 ml of ultra pure water. An aqueous solution containing the metal precursor is prepared and then added dropwise to the solution containing the support. . The pH of the solution is adjusted to 11 and then the reaction medium is then heated at 100 ° C. for 1 hour. After cooling to room temperature, the solid is filtered and washed several times until the filtrate is neutral. The solid is then placed in an oven overnight to be dried (60 ° C, 50-100 mbar). Catalyst C3 is then reduced to 3h of hydrogen at 300 ° C. When the cell has returned to room temperature, the catalyst is purged with argon then passivated by a flow of 1% O 2 / N 2. The catalyst C3 obtained then contains 1.5% by weight of ruthenium. XRD analysis of the catalyst did not reveal ruthenium diffraction peaks. EXAMPLE 4 Preparation of a Catalyst C4 (in Accordance with the Invention): 2.5% by Weight Ru / ZrO2 In a 250 ml three-necked flask, 5 g of a zirconium oxide support ZrO 2 of tetragonal and monoclinic structure ( SBET = 75 m 2 / g) are suspended in 50 ml of ultrapure water at room temperature under nitrogen flow. A 15 ml aqueous solution containing the metal precursor (0.3511 g RuCl 3) is added dropwise. Stirring of the reaction medium then continues for 5 hours. Then the temperature is set at 0 ° C by the use of an ice bath.

A reduction is then made in situ in the liquid phase. 25 ml of formaldehyde (37% by weight in water) are added dropwise over 20 min. After waiting 10 minutes, 10 ml of a solution of KOH (30% by weight) are added dropwise. The catalyst is then filtered and washed until neutrality of the filtrate. The catalyst is then dried in an oven under vacuum overnight (60 ° C, 50-100 mbar). Catalyst C4 contains 2.5% by weight of ruthenium (ICP-EOS). XRD analysis of the catalyst (before testing) did not reveal ruthenium diffraction peaks. EXAMPLE 5 Preparation of a Catalyst C5 (not in accordance with the invention): 2.6% by weight Ru-10 4.3% by weight Re / TiO2 In a 100 ml flask, 5 g of the monometallic catalyst 2.6% by weight Ru / TiO2 (Catalyst C2) are suspended in 20 ml of ultrapure water. An aqueous solution of Re (0.2278 g NH4ReO4 in 10 mL H2O) is added dropwise to the suspension and then stirred for 5 h at room temperature. The catalyst is dried in an oven under vacuum (60 ° C, 50-100 mbar). The solid is then reduced under a stream of hydrogen for 3 h at 450 ° C. When the cell has returned to room temperature, the catalyst is purged with argon then passivated by a flow of 1% O 2 / N 2. The catalyst obtained then contains 2.6% by weight of ruthenium and 4.3% by weight of rhenium. Example 6: Preparation of a Catalyst C6 (not in accordance with the invention): 3% by weight of Pd / TiO 2 In a 500 ml three-necked flask, 10 g of a TiO 2 titanium oxide support of anatase structure (SBET = 95 m2 / g) are suspended in 100 mL of ultrapure water at room temperature under nitrogen flow. A 15 mL aqueous solution containing the metal precursor (0.4702 g K2PdCl4) is added dropwise. Stirring of the reaction medium then continues for 5 hours. Then the temperature is set at 0 ° C by the use of an ice bath. A reduction is then made in situ in the liquid phase. 50 ml of formaldehyde (37% by weight in water) are added dropwise for 20 minutes. After waiting 10 minutes, 20 ml of a solution of KOH (30% by weight) are added dropwise.

The catalyst is then filtered and washed until neutrality of the filtrate. The catalyst is then dried in an oven under vacuum overnight (60 ° C, 50-100 mbar). The catalyst C6 obtained then contains 3% by weight of palladium. The XRD analysis of the catalyst made it possible to determine a crystallite size of 4 nm.

EXAMPLE 7 Transformation of a Solution Containing Levulinic Acid Employing the Catalysts Prepared in Examples 1 to 6 An aqueous solution of 150 ml at 5% by weight of levulinic acid (50 g, ie 430 mmol) 1) is prepared. It is introduced at room temperature into the tank with 1 g of catalyst in powder form. The autoclave is purged three times with 6 MPa of argon and then heated to a temperature of 160 ° C under a pressure of 0.2 MPa argon. Finally, the chosen H2 pressure is adjusted to 15 MPa, which is the time 0 of our catalytic test. The agitation is then set at 1000 rpm and samples are taken at regular intervals. At the end of the reaction (30 hours), the reactor is cooled to room temperature by means of a cold water bath. The products obtained and their mode of analysis: At the outlet of the reactor, the reaction products are analyzed according to several techniques. The reaction products contained in the liquid phase are analyzed by gas chromatography (Shimadzu GC, ZB-FFAP column, FID detector) and by high performance liquid chromatography (HPLC, ICE-Coregel 107H o 7.8 mm × 300 mm, UV detector, RID). The products analyzed by these two techniques contain the following 25 families: 2-butanol, gamma-valerolactone, methyltetrahydrofuran, 2-propanol, 1-propanol, 1-butanol, 1-pentanol, 2-pentanol, levulinic acid, 1.4 pentanediol, pentanoic acid, butyric acid, angelica-lactone The sum of the carbon contained in the water-soluble reaction products is determined by TOC analysis (Total Organic Carbon). Total organic carbon (TOC) in solution was measured on the two analyzers available at Shimadzu TOC-5050A and Shimadzu TOC-VCSH.

Conversion, selectivity and yield The conversion of levulinic acid at a time t is calculated according to the following formula: Levulinic acid conversion (t) = (C levulinic acid (initial) - C levulinic acid (t)) / C levulinic acid charge With: - C levulinic acid (initial) = molar concentration of initial levulinic acid (mol.L-1) - C levulinic acid (t) = molar concentration of levulinic acid at t (mol.L-1) Efficacy a catalyst for the levulinic acid conversion reaction is expressed in selectivities and yields of the various products obtained, in particular: gammavalterolactone (GVL), 1,4-pentanediol (PDO) and methyl tetrahydrofuran (MTHF). ) The molar yield of compound Ci (Rdt (Ci) and the selectivity of compound Ci (Si) are defined as follows: Rdt (Ci) = Si * Conversion (levulinic acid) Si = [Ci] / Zj Cj With Ci: concentration of compound i (mol.L-1) The conversion being equal to 100%, the Efficiency and selectivity merge. The results obtained are summarized in Table 1. It should be noted that at 160 ° C., the levulinic acid conversion is complete so that the yield is equal to the selectivity.

Table 1: Conversion of a feedstock containing 5% by weight of levulinic acid by catalysts C1, C2, C3, C4, C5 and C6 after 30 hours of testing, at 160 ° C, P (H2) = 15 MPa. Conversion Selectivity Acid GVL 2-butanol PDO MTHF Gases Other levulinic cyo% mol Without catalyst 15 0 0 0 0 nd 1.6% wt Ru / TiO2 100 3 27 44 2 20 (C1, Example 1, compliant) 4 2.6 Ru% w / w TiO 2 100 0 61 2 1 36 (C2, Example 2, compliant) 0 1.5 Ru% wt / C 100 29 6 28 11 21 (C3, Example 3, non-compliant) 2.5 Ru% wt / ZrO 2 100 11 18 40 2 14 (C4 Example 4, compliant) 2.6 Ru% wt. -4.3 Re wt.% 100 2 2 90 1 3 2 / TiO 2 (C 5 Example 5, non-compliant) 3 wt% wt / TiO 2 100 94 0 1 0 2 (C 6 Example 6 3 ° at 140 ° C. Traces of the following products are also observed: pentanoic acid, pentanol, 2-pentanol, propanol, methanol and isopropanol. It is found that when the catalyst C3 (1.5% by weight Ru / C, not in accordance with the invention) is used, a total conversion of levulinic acid is obtained with a yield (selectivity) of GVL and 1, 4- pentanediol products which represent 29% and 28% respectively. During the conversion, 2-butanol is also formed insignificantly, with a yield (selectivity) of 6%. When the catalysts C1 and C2 (1.6 wt.% And 2.6 wt.% Ru / TiO2, in accordance with the invention) are used, a total conversion of levulinic acid is also observed which is accompanied by the production of 2- butanol by 27% and 61% respectively.

Thus the use of a catalyst containing ruthenium on a titanium oxide or zirconium oxide support makes it possible to obtain 2-butanol with a yield greater than 10%. When the C4 catalyst is used (2.5 wt% Ru / ZrO2 according to the invention), the 2-butanol yield is 18%. Thus, the use of a catalyst containing ruthenium on a titanium oxide or zirconium oxide support makes it possible to obtain 2-butanol with a yield greater than 15%.

The use of a monometallic catalyst (3`) / 01'd / TiO2) on a titanium oxide support gives 94% GVL, for a total conversion of levulinic acid. No trace of 2-butanol is observed. The use of the C5 bimetallic catalyst (2..4% by weight Ru - 4.6% by weight Re / TiO2) leads to the production of 2% of 2-butanol and 90% of pentanediol, for a total conversion of levulinic acid. .

Claims (14)

REVENDICATIONS1. A process for converting a feedstock comprising levulinic acid to monohydric alcohol in the presence of hydrogen, said process operating in one step at a temperature of from 80 ° C to 250 ° C at a pressure of from 0 , 5 and 20 MPa, and in the presence of a catalyst comprising a metal of groups 7 to 10 selected from platinum (Pt), ruthenium (Ru), iridium (Ir), rhenium (Re), said metal being used alone and a support selected from titanium oxide (TiO 2), zirconium oxide (ZrO 2), and silica (SiO 2), alone or in admixture. 2. Method according to claim 1 wherein said filler comprises water at a content of between 1% and 99% by weight relative to the total weight of the filler, and a levulinic acid content of between 1% and 99% by weight. , relative to the total weight of the load. 3. Method according to one of claims 1 or 2 wherein said metal is a noble metal groups 7 to 10 selected from platinum (Pt) and ruthenium (Ru), said metal being used alone. 4. The method of claim 3 wherein the metal is ruthenium (Ru) used alone. 5. Method according to one of claims 1 to 4 wherein said catalyst comprises a metal content of groups 7 to 10 between 0.1 and 10% by weight relative to the total mass of said catalyst. 6. Method according to one of claims 1 to 5 wherein said support is selected from titanium oxide (TiO 2) and zirconium oxide (ZrO 2), alone or in admixture. The method of claim 6 wherein said support is titanium oxide (TiO 2). 8. Method according to one of claims 1 to 6 wherein said catalyst consists of ruthenium alone and a support selected from titanium oxide or zirconium oxide alone or in admixture. 35 9. The method of claim 8 wherein said catalyst is ruthenium alone and a titanium oxide support. 30 10. Method according to one of claims 1 to 9 wherein the amount of hydrogen introduced is such that the molar ratio hydrogen / levulinic acid is between 1 and 4000 mol / mol. 11. Method according to one of claims 1 to 10 wherein the hourly mass velocity (levulinic acid flow / mass of catalyst) is between 0.01 and 10 1-i1. 12. Method according to one of claims 1 to 11 wherein said process makes it possible to obtain 2-butanol at a selectivity greater than 15 mol%. 13. Method according to one of claims 1 to 12 wherein said method provides a selectivity to methyltétrahydrofuran (MTHF) less than 15 mol%. 14. Method according to one of claims 1 to 12 wherein said charge does not include alcohols.