Selective Hydrogenation of Levulinic Acid in Aqueous Phase

International @ +LCD:CPI:MBEInternational audienceLevulinic acid (LevA) is obtained by an acidic treatment of carbohydrates issued from starch or cellulose [2] and identified by the US Department of Energy as one of the twelve interesting chemicals building blocks [3]. Indeed, a wide variety of high-value added products such as Gamma-valerolactone (GVL), 1,4-pentanediol (PDO) or methyltetrahydrofuran (MTHF) can be obtained by the selective hydrogenation of LevA. In this work, we evaluated the influence of several supported mono and bimetallic catalysts (Ru, Pd or Pt associated with Re) on the selectivity of the reaction. We have investigated the influence of (i) the nature of the support (C or TiO2); (ii) the mode of preparation of the monometallic catalysts (CE: Cationic Exchange; SI: Successive Impregnation; DP: Deposition-Precipitation); (iii) the ratio of the metallic promoter (Re/noble metal) and (iv) the operating conditions on the reaction rate and the selectivity into the desired products

Selective hydrogenation of levulinic acid in aqueous phase

International @ BIOVERT+LCD:MBE:CPIInternational audienceLevulinic acid (LevA) is obtained by an acidic treatment of carbohydrates issued from starch or cellulose [2] and identified by the US Department of Energy as one of the twelve interesting chemicals building blocks [3]. Indeed, a wide variety of high-value added products such as Gamma-valerolactone (GVL), 1,4-pentanediol (PDO) or methyltetrahydrofuran (MTHF) can be obtained by the selective hydrogenation of LevA. In this work, we evaluated the influence of several supported mono and bimetallic catalysts (Ru, Pd or Pt associated with Re) on the selectivity of the reaction. We have investigated the influence of (i) the nature of the support (C or TiO2); (ii) the mode of preparation of the monometallic catalysts (CE: Cationic Exchange; SI: Successive Impregnation; DP: Deposition-Precipitation); (iii) the ratio of the metallic promoter (Re/noble metal) and (iv) the operating conditions on the reaction rate and the selectivity into the desired products

Selective Hydrogenation of Levulinic Acid in Aqueous Phase

International @ +LCD:CPI:MBEInternational audienceLevulinic acid (LevA) is obtained by an acidic treatment of carbohydrates issued from starch or cellulose [2] and identified by the US Department of Energy as one of the twelve interesting chemicals building blocks [3]. Indeed, a wide variety of high-value added products such as Gamma-valerolactone (GVL), 1,4-pentanediol (PDO) or methyltetrahydrofuran (MTHF) can be obtained by the selective hydrogenation of LevA. In this work, we evaluated the influence of several supported mono and bimetallic catalysts (Ru, Pd or Pt associated with Re) on the selectivity of the reaction. We have investigated the influence of (i) the nature of the support (C or TiO2); (ii) the mode of preparation of the monometallic catalysts (CE: Cationic Exchange; SI: Successive Impregnation; DP: Deposition-Precipitation); (iii) the ratio of the metallic promoter (Re/noble metal) and (iv) the operating conditions on the reaction rate and the selectivity into the desired products

Selective hydrogenation of levulinic acid in aqueous phase

International @ BIOVERT+LCD:MBE:CPIInternational audienceLevulinic acid (LevA) is obtained by an acidic treatment of carbohydrates issued from starch or cellulose [2] and identified by the US Department of Energy as one of the twelve interesting chemicals building blocks [3]. Indeed, a wide variety of high-value added products such as Gamma-valerolactone (GVL), 1,4-pentanediol (PDO) or methyltetrahydrofuran (MTHF) can be obtained by the selective hydrogenation of LevA. In this work, we evaluated the influence of several supported mono and bimetallic catalysts (Ru, Pd or Pt associated with Re) on the selectivity of the reaction. We have investigated the influence of (i) the nature of the support (C or TiO2); (ii) the mode of preparation of the monometallic catalysts (CE: Cationic Exchange; SI: Successive Impregnation; DP: Deposition-Precipitation); (iii) the ratio of the metallic promoter (Re/noble metal) and (iv) the operating conditions on the reaction rate and the selectivity into the desired products

Effect of Au on Pd supported over HMS and Ti doped HMS as catalysts for the hydrogenation of levulinic acid to gamma-valerolactone

SSCI-VIDE+CDFA+MLT:LCD:CPIInternational audienceThe effect of different supports, silica HMS and Ti doped silica HMS, on the catalytic performance of mono (Pd) and bimetallic (Pd-Au, Pd-Re) catalysts, containing 2 wt% of each metal, for the hydrogenation of levulinic acid in water was studied. The catalytic behavior of the materials was evaluated in terms of conversion of the starting levulinic acid and selectivity to gamma-valerolactone. The surface and structural properties of the catalysts were investigated by means of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) performed on fresh and spent materials. A synergic effect of Au and Ti on Pd sample was observed with the consequent formation of a PdTi alloy responsible of the good performance of the catalyst. (C) 2014 Elsevier B.V. All rights reserved

selective aqueous-phase hydrogenation of levulinic acid to pentanediol over bimetallic catalysts: the influence of the promoter

SSCI-VIDE+CDFA+MBE:CPIInternational audienceNowadays, a large range of acids are produced from biomass either through chemical or biochemical transformations. Levulinic acid (LevA) can be cost-effectively produced from lignocellulosic biomass via a simple acid-catalyzed hydrolysis process (Biofine technology [1]). The hydrogenation of LevA over supported metallic catalysts leads to the formation of g-valerolactone (GVL), 1,4-pentanediol (PenDO) and methytetrahydrofurane (MTHF). The selectivity depends on the nature of the metal and on the reaction conditions. While GVL was predominantly formed over monometallic catalysts, PenDO and MTHF were mainly produced over bimetallic Re-Ru catalysts [2]. Since partial leaching of Re was observed during the aqueous-phase hydrogenation of succinic acid [3], different other promotors (Mo, Sn, W) were evaluated in the hydrogenation of LevA.Materials and MethodsBimetallic catalysts were prepared by successive impregnations of an active carbon (L3S CECA) with aqueous solutions of the metallic salts and reduction under H2. Hydrogenation reactions were conducted in a 300 mL Hastelloy Parr 4560 autoclave equipped with an electrically heated jacket, a turbine stirrer with magnetic driver, and a liquid sample line. In a typical reaction, the reactor was loaded with 7.5 g acid, 142 g water and 1 g catalyst. After purging with Ar, the reaction medium was heated to the desired temperature (typically 140°C) and H2 pressure (150 bar) was introduced to initiate the reaction. The liquid samples periodically withdrawn from the reactor were analyzed using both HPLC chromatography with UV and RID detections (ICSep Coregel 107H column, 0.005 N H2SO4 as mobile phase at a flow rate of 0.5 mL.min-1) and gas chromatography (FFAP column, using He as carrier gas). Acids, lactones, diols, cyclic ethers and by-products (propionic, butyric and acetic acids, n-butanol, and n-propanol) could be quantified. Total Organic Carbon (TOC) was also measured using a Shimadzu TOC-VCHS analyzer.Results and DiscussionRegardless the nature of the promotor, complete hydrogenation of LevA to GVL was observed within less than one hour. The reaction rate of the subsequent hydrogenation of GVL was highly dependent on the Ru/promoter ratio as well as on the nature of the promoter. In the presence of Sn-Ru/C, the hydrogenation of GVL was very slow; after 30 h only a 16% PenDO yield was obtained. Similarly, modest reaction rate was achieved in the presence of W-Ru/C catalysts. Conversely, interesting results were observed in the presence of Mo-Ru/C catalysts (Figure 1). Using a Mo/Ru molar ratio in the range from 0.26 up to 1.8, it was shown that the higher the Mo/Ru ratio, the lower the reaction rate. However, the selectivity to PenDO was not affected and was as high as 75-80%. Furthermore, no Mo leaching was detected during the reaction. Figure 1: Evolution of the concentration of the products during the hydrogenation of LevA (not shown) over 0.5%Mo-2%Ru/C (dotted line) and 3.2%Re-2.5%Ru/C (full line)Since formic acid is co-produced in equimolar amount as LevA during the industrial production of LevA, its presence in the feed was studied. Over both catalysts (Re and Mo promoted), a dramatic decrease in the reaction rate (together with hydrogenation of formic acid) was observed. However, the final selectivity to PenDO was unchanged. The higher stability of Mo-based catalysts compared to Re-based catalysts was confirmed

selective aqueous-phase hydrogenation of levulinic acid to pentanediol over bimetallic catalysts: the influence of the promoter

SSCI-VIDE+CDFA+MBE:CPIInternational audienceNowadays, a large range of acids are produced from biomass either through chemical or biochemical transformations. Levulinic acid (LevA) can be cost-effectively produced from lignocellulosic biomass via a simple acid-catalyzed hydrolysis process (Biofine technology [1]). The hydrogenation of LevA over supported metallic catalysts leads to the formation of g-valerolactone (GVL), 1,4-pentanediol (PenDO) and methytetrahydrofurane (MTHF). The selectivity depends on the nature of the metal and on the reaction conditions. While GVL was predominantly formed over monometallic catalysts, PenDO and MTHF were mainly produced over bimetallic Re-Ru catalysts [2]. Since partial leaching of Re was observed during the aqueous-phase hydrogenation of succinic acid [3], different other promotors (Mo, Sn, W) were evaluated in the hydrogenation of LevA.Materials and MethodsBimetallic catalysts were prepared by successive impregnations of an active carbon (L3S CECA) with aqueous solutions of the metallic salts and reduction under H2. Hydrogenation reactions were conducted in a 300 mL Hastelloy Parr 4560 autoclave equipped with an electrically heated jacket, a turbine stirrer with magnetic driver, and a liquid sample line. In a typical reaction, the reactor was loaded with 7.5 g acid, 142 g water and 1 g catalyst. After purging with Ar, the reaction medium was heated to the desired temperature (typically 140°C) and H2 pressure (150 bar) was introduced to initiate the reaction. The liquid samples periodically withdrawn from the reactor were analyzed using both HPLC chromatography with UV and RID detections (ICSep Coregel 107H column, 0.005 N H2SO4 as mobile phase at a flow rate of 0.5 mL.min-1) and gas chromatography (FFAP column, using He as carrier gas). Acids, lactones, diols, cyclic ethers and by-products (propionic, butyric and acetic acids, n-butanol, and n-propanol) could be quantified. Total Organic Carbon (TOC) was also measured using a Shimadzu TOC-VCHS analyzer.Results and DiscussionRegardless the nature of the promotor, complete hydrogenation of LevA to GVL was observed within less than one hour. The reaction rate of the subsequent hydrogenation of GVL was highly dependent on the Ru/promoter ratio as well as on the nature of the promoter. In the presence of Sn-Ru/C, the hydrogenation of GVL was very slow; after 30 h only a 16% PenDO yield was obtained. Similarly, modest reaction rate was achieved in the presence of W-Ru/C catalysts. Conversely, interesting results were observed in the presence of Mo-Ru/C catalysts (Figure 1). Using a Mo/Ru molar ratio in the range from 0.26 up to 1.8, it was shown that the higher the Mo/Ru ratio, the lower the reaction rate. However, the selectivity to PenDO was not affected and was as high as 75-80%. Furthermore, no Mo leaching was detected during the reaction. Figure 1: Evolution of the concentration of the products during the hydrogenation of LevA (not shown) over 0.5%Mo-2%Ru/C (dotted line) and 3.2%Re-2.5%Ru/C (full line)Since formic acid is co-produced in equimolar amount as LevA during the industrial production of LevA, its presence in the feed was studied. Over both catalysts (Re and Mo promoted), a dramatic decrease in the reaction rate (together with hydrogenation of formic acid) was observed. However, the final selectivity to PenDO was unchanged. The higher stability of Mo-based catalysts compared to Re-based catalysts was confirmed

Kinetic modelling of the catalytic dehydrogenative coupling of butanol catalyzed by a Ru complex: influence of gas-liquid mass transfer of produced hydrogen

SSCI-VIDE+CDFA+LCD:PFOInternational audienceA growing interest towards efficient catalytic systems has led over the recent years to the development of a new generation of catalysts for alcohol dehydrogenative coupling (ADC).[1] This green, atom-efficient reaction is capable of turning alcohol derivatives into higher value and chemically more attractive ester molecules. In our project, the main objective is to develop a catalytic process maximizing the ester produced without any solvent starting here from butanol into butyl butyrate. To optimize the process, we investigate in this present work a kinetic model describing the activity of several molecular catalysts (Ru-based pincer complexes) on the catalytic ADC (Figure 1) including the coupling with the H2 gas-liquid mass transfer.According to the detailed reaction scheme presented in Figure 1, we have developed a kinetic model including 5 parameters. Kinetic parameters values have been obtained by adjustment solving a 7 equation differentials according to the mass balance of the semi-batch reactor used in the study (trust-region reflective algorithm for objective function minimization and ode15s MATLAB function for mass balance integration). A statistical analysis is performed in order to estimate the validity of the model and estimated parameters. Figure 1 : Mechanism proposed for the catalytic dehydrogenative coupling of alcoholInfluence of gas-liquid mass transfer of H2 has been carefully studied and included in the simulation because the concentration of H2 in the liquid phase is impacting the equilibrium between the active (monohydride-amido) and inactive (dihydride-amino) form of the catalyst. Hydrogen kLa has been estimated from a correlation found in the literature. [2]Figure 2 illustrates the experimental (maker) and fitted (line) concentration of butanol, butyl butyrate, simulated H2 in liquid and gas phase as a function of time. The equilibrium between the two states of catalyst is also predicted by the model (Figure 2 b). Figure 2 : a) Experimental and theoretical concentration as a function of time; b) Evolution of the concentration of the active and inactive species of catalyst as a function of timeMore than 200 catalytic tests with various catalytic system or temperature were modeled using the model developed. By plotting the experimental concentration versus the predicted values, a parity plot is obtained below. According to the parity plot and the statistical/residuals analysis, we have found that the kinetic model was able to properly describe experimental results. The rate constant predicted for the second step is much higher than the one for the first step (480 000 versus 12 000 h-1) reacts quickly to give the butyl butyrate. A study on the impeller rotation rate (300 rpm up to 1800 rpm) has shown an effect on apparent kinetics due to his effect on the initial value of kLa (0.008 versus 0.6 s-1). Figure 3 : Parity plot of the butanol and the butyl butyrate, experimental concentration as a function of predicted valuesAcknowledgments: This work has been performed, in partnership with the SAS PIVERT, within the frame of the French Institute for the Energy Transition (Institut pour la Transition Energétique (ITE) P.I.V.E.R.T. www.institut-pivert.com) selected as an Investments for the Future (âInvestissements dâAvenirâ). This work was supported, as part of the Investments for the Future, by the French Government under the reference ANR-001-01.[1] C. Gunanathan and D. Milstein, Science, 341 2013, DOI: 10.1126/science.1229712[2] V. Meille, N. Pestre, P. Fongarland and C. de Bellefon, Ind. Eng. Chem. Res. 43 2004, 924â927

Transformation of butanediols in alkaline aqueous media over platinum-supported catalysts

SSCI-VIDE+CDFA+MBE:CPIInternational audienceNon

Transformation of butanediols in alkaline aqueous media over platinum-supported catalysts

SSCI-VIDE+CDFA+MBE:CPIInternational audienceNon