Vapor Phase Hydrogenolysis Of Glycerol Research Articles

Review of the Development of Heterogeneous Catalysts for Liquid and Vapor Phase Hydrogenolysis of Glycerol to Propylene Glycol (1,2-Propanediol): State-of-the-Art and Outlook

In the last two decades, various glycerol value addition techniques have been developed and discussed in the literature. Among all these processes, conversion of glycerol to 1,2-propanediol (1,2-PDO) has been recognized as one of the promising and commercially attractive glycerol value addition routes. This review is an attempt to scan out the progress in catalysts design and development for liquid and vapor phase glycerol hydrogenolysis for the production of 1,2-PDO. The development of supported and mixed metal oxide catalysts with their novel catalytic characteristics for glycerol conversion and 1,2-PDO selectivity has been scrutinized systematically. It was observed that among the non-noble metal catalysts, Cu-based catalysts have shown promising activity toward 1,2-PDO; however, their stability is an issue. Among noble metals, Pt- and Ru-based catalysts were reported active for glycerol conversion. Comparatively, catalysts composed of Pt, Ru, Pd as a noble metal, and Cu as a non-noble metal have resulted in higher catalytic activity and 1,2-PDO selectivity. This review also summarizes different reaction pathways for hydrogenolysis of glycerol to 1,2-PDO, the effect of additives (solid acid and base), and methods of catalyst preparation on the catalyst performances. Further, glycerol hydrogenolysis with in situ H2 production by glycerol reforming or by chemical transfer hydrogen using various hydrogen donors and the effect of different solvents on the glycerol hydrogenolysis process are also discussed. Reaction kinetic models are also included at the end.

Selective Hydrogenolysis of Biodiesel Waste Bioglycerol Over Titanium Phosphate (TiP) Catalysts: The Effect of Pt & WO3 Loadings

Glycerol is an important by-product (biowaste) from biodiesel production. Transformation of glycerol into value-added compounds is critical in improving the overall efficiency of the biodiesel production. In this work, a sustainable and cleaner production of 1,3-propanediol (1,3-PDO) by vapor phase hydrogenolysis of glycerol was performed over titanium phosphate (TiP) supported catalysts by varying the Pt and WO3 loadings (5–20 wt.%). The WO3 promoted Pt modified TiP catalysts were prepared by a simple wet impregnation method and characterized by various analytical techniques in determining the key properties. Furthermore, the catalyst activity and stability were studied under different reaction conditions. The synergistic effects of Pt and WO3 loadings on the final performance of the catalyst has been significant in improving the hydrogen transfer rate. Both Pt and WO3 promotional effects is envisaged the enhanced catalytic properties in conjunction with TiP support acidity. WO3 incorporation increased Brønsted acidity and formed strong interactions with Pt over TiP support. Both Lewis and Brønsted acid sites presented but BAS played a key role in enhancing the 1,3-PDO selectivity in a bifunctional dehydration-hydrogenation reaction mechanism of glycerol. The effect of reaction temperature, contact times and the weight hour space velocity were evaluated. Overall, under optimized reaction conditions, 2 wt.% Pt-10 wt.% WO3/TiP catalyst displayed superior activity with a maximum glycerol conversion of ~ 85% and ~ 51% of 1,3-PDO selectivity achieved at time on stream of 4 h.Graphical

Kinetics of glycerol dehydration-hydrogenation reaction in the vapor phase in a fixed bed down flow tubular reactor over a bi-functional Cu-Zn/MgO catalyst

Kinetic models were developed for the vapor phase hydrogenolysis of glycerol in a fixed bed down flow tubular reactor over a highly stable bi-functional Cu-Zn/MgO catalyst. The kinetic experiments were conducted at atmospheric pressure, at different temperatures (200–220 °C), and contact time (W/FGo) (101.5–609 kgcat. h kmol−1), respectively. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) and Eley-Rideal (ER) type kinetic models were tried considering a two-step glycerol dehydration-hydrogenation process. The model equations were solved in MATLAB by using the ode23 function and the kinetic parameters were optimized by using the genetic algorithm optimization technique. The activation energy for the dehydration and hydrogenation steps was found to be 57.73 ± 10 kJ/mol and 156.71 ± 10 kJ/mol from LHHW kinetic model and 82.6 ± 8.3 kJ/mol and 146.2 ± 3.9 kJ/mol from ER kinetic model, respectively. Results demonstrated that both the models were fitted very well with the experimental data generated. However, the parity plots of the simulated and experimental partial pressure of glycerol, acetol, and 1,2-PD suggested that ER model was more appropriate as compared to the LHHW model.

Production of propylene glycol (propane-1,2-diol) in vapor phase over Cu–Ni/γ-Al2O3 catalyst in a down flow tubular reactor: effect of catalyst calcination temperature and kinetic study

The modification of physicochemical characteristics of 20 wt% Cu–Ni (1:1)/γ-Al2O3 catalyst by varying the calcination temperature and its effect in vapor phase hydrogenolysis of glycerol to propane-1,2-diol was examined in packed bed down flow tubular reactor. The catalyst calcined at 400 °C rendered the highest glycerol conversion (~ 100%) and propane-1,2-diol selectivity (~ 89.5%) at 220 °C, 0.75 MPa and at the weight hourly velocity of (WHSV) of 1.3 h−1. The bifunctional nature of the new Cu–Ni bimetallic phase along with very high metal dispersion (~ 20%), lower crystallite size (≤ 20 nm) and high metal surface area ~ 30 m2 g−1 were the primary reason for the higher activity and selectivity to propane-1,2-diol. Furthermore, using a two-step reaction mechanism (glycerol dehydration to acetol and subsequent hydrogenation of acetol to propane-1,2-diol), a kinetic model was developed based on Eley–Rideal approach. The activation energies for the formation of acetol and propane-1,2-diol were calculated as 55.14 and 50.87 kJ mol−1, respectively.

Production of propylene glycol (1,2-propanediol) by the hydrogenolysis of glycerol in a fixed-bed downflow tubular reactor over a highly effective Cu–Zn bifunctional catalyst: effect of an acidic/basic support

Very high glycerol conversion of 98.5% with ∼89% selectivity to propylene glycol was achieved at a very low pressure (0.72 MPa) over Cu–Zn/MgO catalyst for vapor phase hydrogenolysis of glycerol. Uniformly distributed partially reduced copper species (Cu2O, CuO, and Cu0) and higher basicity of the catalyst were the governing factors for higher selectivity to propylene glycol.

Tuning Y-zeolite based catalyst with copper for enhanced activity and selectivity in vapor phase hydrogenolysis of glycerol to 1,2-propanediol

Highly dispersed copper oxide species supported on a Y-zeolite with different Si/Al ratios (5.1, 12, 30, and 60) were synthesized by an incipient wet impregnation method. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption (BET), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffused reflectance spectroscopy (UV-DRS), N2O chemisorption, Pyridine-adsorption Fourier transform Infrared Spectroscopy (Py-FTIR), NH3 temperature programmed desorption (NH3-TPD) and temperature programmed reduction (TPR). Copper dispersion and metallic area were measured by the N2O decomposition method. The amount of Bronsted and Lewis acidic sites was analyzed by Pyridine adsorption followed by FT-IR. Performance of the prepared catalysts in vapor phase hydrogenolysis of glycerol to 1,2-propanediol was evaluated by using a fixed-bed stainless-steel reactor at 0.2MPa and 210°C. The studies revealed that the 3wt.% CuO/Y-zeolite (Si/Al=5.1) catalyst was highly active in glycerol hydrogenolysis showing 92% conversion of glycerol and 83% selectivity to 1,2-propanediol. This seems to originate from high dispersion of Cu, smaller Cu crystallite size, and the presence of a high amount of surface beneficial acido-basic properties.

Vapor phase hydrogenolysis of glycerol to 1,2-propanediol at atmospheric pressure over copper catalysts supported on mesoporous alumina

The present work explores the hydrogenolysis of glycerol to produce 1,2-propanediol in vapor phase at atmospheric pressure over copper catalysts supported on mesoporous alumina. Catalysts were prepared by alumina impregnation varying CuO loading between 3wt% and 30wt%. The textural and structural characteristics of the catalysts were determined by N2 sorptometry (BET), powder X-ray diffraction (PXRD), temperature programmed reduction (TPR) and N2O chemisorption (copper metallic area). The characterization showed that all catalysts present textural properties characteristic of mesoporous solids, such as the adsorption isotherms which are type IV. Based both on characterization and activity results, it was possible to conclude that the yield to 1,2-propanediol presented a non-monotonic dependence on total copper metallic area. In addition, it was proved that 1,2-propanediol production is associated with the presence of highly dispersed CuO phase in the solids. Promising results were obtained with CuO(15)Al catalysts, taking into account that the performance can be improved by increasing residence time.

Direct Hydrogenolysis of Glycerol to Biopropanols over Metal Phosphate Supported Platinum Catalysts

Several metal phosphate supported platinum catalysts (Pt/AlP, Pt/TiP, Pt/ZrP and Pt/NbP) have been synthesized for the direct hydrogenolysis of glycerol to produce bio-propanols performed under mild reaction conditions. The catalysts were screened for its activity towards production of propanols from glycerol hydrogenolysis and the reaction has been optimized by studying various reaction parameters such as effect of platinum loading, reaction temperature, hydrogen flow rate, glycerol concentration and reaction time. Among the catalysts investigated, 2Pt/TiP presented a remarkable catalytic performance for vapour phase hydrogenolysis of glycerol with 100% conversion of glycerol and 97% selectivity to total propanols (1-propanol + 2-propanol) at 220 °C and atmospheric pressure. The high efficiency of 2Pt/TiP catalyst is probably be due to the strong acidity of catalyst and the uniform dispersion of small Pt particles on surface of TiP that could enable the dehydration-hydrogenation route of glycerol hydrogenolysis. Further, the structural characteristics of used catalyst have been investigated in order to understand the stability of the catalyst. Therefore, a more economical and sustainable approach of producing value added propanols from bio-derived glycerol over highly efficient catalytic system is herein presented.

Platinum Supported on H-Mordenite: A Highly Efficient Catalyst for Selective Hydrogenolysis of Glycerol to 1,3-Propanediol

The selective production of 1,3-propanediol from glycerol under mild reaction conditions is of high interest. The current work describes the use of a highly selective catalyst consisting of platinum supported on mordenite zeolite employed for the first time for vapor phase hydrogenolysis of glycerol to 1,3-propanediol under atmospheric pressure. The catalysts with varying Pt content (0.5–3 wt %) were prepared and thoroughly characterized by X-ray diffraction, temperature-programmed desorption of ammonia, FT-IR of adsorbed pyridine, CO chemisorptions, transmission electron microscopy, X-ray photoelectron spectroscopy, and BET surface area. The influence of reaction parameters has been studied to unveil the optimized reaction conditions. A high 1,3-propanediol selectivity (48.6%) was obtained over a 2 wt % Pt/H–mordenite catalyst at 94.9% glycerol conversion. According to the results obtained, the selectivity to 1,3-propanediol is better influenced by Pt dispersion and Bronsted acidity of the support. A pla...

Catalytic Functionalities of Nano Ruthenium/gamma-Al2O3 Catalysts for the Vapour Phase Hydrogenolysis of Glycerol.

A series of Ruthenium catalysts with different Ru contents supported on gamma-alumina were prepared by deposition-precipitation method. The catalysts were characterized by X-ray diffraction (XRD), trans- mission electron microscopy (TEM), temperature programmed reduction (TPR), CO-chemisorption, surface area and pore-size distribution (PSD) measurements. The catalytic activities were evaluated for the vapour phase hydrogenolysis of glycerol to propanediols. The pore size distribution (PSD) results suggest that Ru loadings considerably affect the pore volume, pore diameter and surface area. The particle size measured from CO-chemisorption and TEM analysis are well correlated to the activity results during the hydrogenolysis reaction. The catalytic properties of Ru/gamma-Al2O3 catalysts were evaluated for the first time over vapour phase hydrogenolysis of glycerol to propanediols.

Vapor phase hydrogenolysis of glycerol to 1,2-propanediol over γ-Al2O3 supported copper or nickel monometallic and copper–nickel bimetallic catalysts

Vapor phase hydrogenolysis of glycerol was investigated over γ-Al2O3 supported copper or nickel monometallic and copper–nickel bimetallic catalysts prepared by incipient wetness impregnation method. Catalytic results demonstrated that bimetallic catalysts were more selective to 1,2-propanediol (1,2-PDO) as compare to monometallic catalysts. Bimetallic copper–nickel phase promoted the selective hydrogenolysis of C–O bond and limited the cleavage of C–C bond which significantly reduced the formation of undesirable products. Very high 1,2-PDO yield of 88% at 98.5% glycerol conversion was achieved over 20 wt% Cu–Ni (1:1)/γ-Al2O3 catalyst at very low hydrogen to glycerol mole ratio of 54.6 and at 220 °C and 0.75 MPa pressure. Superior performance of 20 wt% Cu–Ni (1:1)/γ-Al2O3 catalyst was attributed to strong synergetic interaction due to the formation of copper–nickel bimetallic phase as confirmed by the XRD result. Times-on-stream study and the characterization results of the spent catalyst confirmed the structural stability of the copper–nickel bimetallic phase of 20 wt% Cu–Ni (1:1)/γ-Al2O3 catalyst and negligible carbon deposition (0.03 mmol carbon gcat−1 h−1) on the catalyst after prolonged contact under hydrogen environment.

Catalytic functionalities of nano Ru catalysts supported on TiO2–ZrO2 mixed oxide for vapor phase hydrogenolysis of glycerol to propanediols

Vapor phase hydrogenolysis of glycerol was studied over Ru catalysts supported on TiO2–ZrO2 binary oxide. Ru catalysts with various ruthenium loadings from 1.0 to 6.0 wt% were prepared by deposition–precipitation method on the TiO2–ZrO2 mixed oxide support. These catalysts were characterized by X-ray diffraction, H2 temperature-programmed reduction, NH3 temperature-programmed desorption, transmission electron microscopy, BET surface area, XPS and CO chemisorption measurements. The catalysts exhibited superior performance for the vapor phase hydrogenolysis of glycerol at moderate temperature and atmospheric pressure. The mixed oxide support plays a significant role in improving the catalytic activity for the production of propanediols. The glycerol conversion and the selectivity of various products depend on the catalyst preparation method and also on the Ru content. The influence of acidity of the catalyst and its correlation to the catalytic performance (selectivity and conversion) has been studied. The weak and strong acidic sites of the catalysts measured by NH3-TPD play a key role in selective formation of 1,2-propanediol and 1,3-propanediol. XRD, TEM, XPS and CO chemisorption studies revealed that ruthenium was well dispersed on TiO2–ZrO2 which further contributed to the superior catalytic activity for glycerol hydrogenolysis.

Vapour phase hydrogenolysis of glycerol to propanediols over Cu/SBA‐15 catalysts

AbstractBACKGROUNDBiomass‐derived glycerol is emerging as a renewable, cheap and versatile feedstock for the production of a variety of chemicals and fuels.RESULTSCu catalysts with varying copper loadings ranging from 2.5 to 20 wt% supported on SBA‐15 were investigated for the vapour phase hydrogenolysis of glycerol to propanediols. The dispersion of Cu and copper metal area on mesoporous SBA‐15 was determined by pulse N2O decomposition measurements. The X‐ray diffraction patterns suggest that the presence of highly dispersed copper oxide species at lower Cu loadings (≤5Cu) and as crystalline CuO phase at higher Cu loadings (≥10 wt% Cu). The acidity of the catalysts measured by NH3 ‐TPD method reveals that the acidity of the samples increases with increase of copper loading up to 5 wt% and decreases at higher copper loadings. The catalytic functionalities during the vapour phase hydrogenolysis of glycerol to propanediols are correlated with the copper oxide dispersion and also with the acidic propertiesCONCLUSIONSIn summary, 5Cu/SBA‐15 catalyst was found to consist of highly dispersed copper oxide on the support, evidenced by XRD, TPR and N2O decomposition studies. This catalyst exhibits high glycerol conversion (90%) and 84% selectivity of 1,2‐propanediol. The activity results are well correlated with Cu dispersion and acidity of the catalysts. © 2015 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Metal–acid bifunctional catalysts for selective hydrogenolysis of glycerol under atmospheric pressure: A highly selective route to produce propanols

Metal–acid bifunctional catalysts containing platinum and heteropolyacids (HPA) in supported on zirconia have been employed for the selective vapor phase hydrogenolysis of glycerol to propanols (1-propanol+2-propanol) under normal atmospheric pressure. The Pt–HPA/ZrO2 catalysts (HPAs such as silicotungstic acid (STA), phosphotungstic acid (PTA), phosphomolybdic acid (PMA) and silicomolybdic acid (SMA)) were prepared by impregnation method and the calcined catalysts were characterized by means of X-ray powder diffraction, FTIR, Raman spectroscopy, BET surface area, CO chemisorption and NH3-Temperature-programmed desorption methods. The characterization results reveal the presence of well dispersed Pt metallic phase and Keggin structure of HPAs on support. The catalytic performance during glycerol hydrogenolysis is well correlated with Pt dispersion and the acidic properties of catalysts. Among the tested catalysts, it was found that Pt–PTA/ZrO2 exhibited excellent selectivity to propanols (98%) with total glycerol conversion at 230°C. A detailed study was made on the effect of various reaction parameters such as the influence of reaction temperature, reduction temperature, glycerol concentration, hydrogen flow rate, feed flow rate and HPA loading to unveil the optimized reaction conditions. Reaction temperature was observed to have a significant effect on the glycerol conversion and product selectivity. The spent catalysts were also characterized by the X-ray diffraction, NH3-TPD and SEM analysis to investigate the changes in catalytic performance and causes of catalyst deactivation.

Vapor-phase hydrogenolysis of glycerol over nanostructured Ru/MCM-41 catalysts

A series of catalysts with different Ru contents supported on MCM-41 were prepared by micro-emulsion (ME) method. These catalysts were characterized by X-ray diffraction, BET-surface area, H2-temperature programmed reduction, pore size distribution, XPS, transmission electron microscopy, and CO-chemisorption measurements. The catalytic properties of Ru/MCM-41 catalysts were evaluated during the vapor phase hydrogenolysis of glycerol on various reaction parameters. The catalysts have shown an unprecedented activity for the complete hydrogenolysis of glycerol at moderate reaction temperature under normal atmospheric pressure. The nanostructured ruthenium deposited on MCM-41 support plays a significant role in improving the catalytic activity and its stability. The glycerol conversion and the selectivity of 1,2propanediol (1,2-PD), 1,3-propanediol (1,3-PD) and various products were mainly depend on the method of catalyst preparation, effect of support and also on the Ru loading.

Vapour phase hydrogenolysis of glycerol over nano Ru/SBA-15 catalysts on the effect of preparatory routes and metal precursors.

The effect of preparation method and metal precursor of ruthenium employed during the preparation of Ru/SBA-15 catalysts were investigated. The catalytic functionalities are evaluated during the vapour phase hydrogenolysis of glycerol to 1,2-propyleneglycol, 1,3-propylene glycol and ethylene glycol. The catalysts exhibit high conversion/selectivity for 3 wt%Ru (3Ru/SBA-15) catalysts during glycerol hydrogenolysis. CO-chemisorption results suggest that the variation in the dispersion of Ru on SBA-15 support. These catalysts were characterized by XRD, TPR, TEM, BET surface area, pore size distribution and CO-chemisorption measurements. The Ru/SBA-15 catalysts synthesized from micro-emulsion method and polyol method have shown higher catalytic activity than the samples prepared by impregnation method and deposition-precipitation method. The catalytic behavior during glycerol hydrogenolysis is attributed to the formation of nano particles of ruthenium.

Effect of Ag loading on Cu/Al2O3 catalyst in the production of 1,2-propanediol from glycerol

The vapor-phase hydrogenolysis of glycerol was performed at a gradient temperature and ambient hydrogen pressure over a commercial Cu/Al2O3 catalyst modified with silver. Addition of Ag into Cu/Al2O3 catalysts was found to be efficient in inhibiting the decomposition of glycerol to produce ethylene glycol and gave a yield of 1,2-propanediol higher than that of the original Cu/Al2O3 without Ag. To minimize the ethylene glycol formation, the suitable loading of Ag was 1wt.%. Since the Ag loading decreases the hydrogenation ability of the Cu/Al2O3 catalyst, 1wt.% Ag-loaded Cu/Al2O3 catalyst was placed on the upper layer of the fixed catalyst bed and the Cu/Al2O3 catalyst was placed on the bottom layer for achieving much higher 1,2-propanediol yield. The effect of temperatures of the top, the interlayer, and the bottom of the catalyst bed on the yield was also examined: a high 1,2-propanediol yield of 98.3%, which is the highest value under ambient H2 pressure conditions, was achieved at a gradient temperature from 170 to 105°C and a glycerol concentration of 15wt.%.

Continuous production of 1,2‐propanediol by the selective hydrogenolysis of solvent‐free glycerol under mild conditions

AbstractBACKGROUND: The conversion of glycerol to value‐added derivatives is now critical, owing to the large surplus of glycerol from biodiesel production. The main objective of this work is to develop a novel process for converting solvent‐free glycerol to 1,2‐propanediol.RESULTS: Several catalysts were screened for aqueous‐phase hydrogenolysis of glycerol in an autoclave. The most effective catalysts (Ni/Al2O3, Cu/ZnO/Al2O3) were further tested for vapor phase hydrogenolysis in a fixed‐bed. Ni/Al2O3 did not prove as effective for the production of 1,2‐propanediol because of the high selectivity to CH4 and CO. Over Cu/ZnO/Al2O3, glycerol was mainly converted to the desired 1,2‐propanediol and the reaction intermediate acetol. The production of 1,2‐propanediol was favoured at higher hydrogen pressure. At 190 °C and 0.64 MPa, near complete conversion of glycerol was achieved with 1,2‐propanediol selectivity up to 92%. In addition, a higher concentration (between 43.4% and 0.8%) of acetol was detected and an approximately stoichiometric relationship was found between acetol and 1,2‐propanediol.CONCLUSION: 1,2‐propanediol can be produced with high yields via the vapor phase hydrogenolysis of glycerol over Cu/ZnO/Al2O3. Furthermore, the mechanism of 1,2‐propanediol formation is suggested to proceed mainly through an acetol route over Cu/ZnO/Al2O3. Copyright © 2008 Society of Chemical Industry

97/04527 Oil shock ‘imminent’ if heavies are slow or expensive to produce: Bentley, R. Energy World, June 1997, 250, 20–22

Metal–acid bifunctional catalysts containing platinum and heteropolyacids (HPA) in supported on zirconia have been employed for the selective vapor phase hydrogenolysis of glycerol to propanols (1-propanol + 2-propanol) under normal atmospheric pressure. The Pt–HPA/ZrO2 catalysts (HPAs such as silicotungstic acid (STA), phosphotungstic acid (PTA), phosphomolybdic acid (PMA) and silicomolybdic acid (SMA)) were prepared by impregnation method and the calcined catalysts were characterized by means of X-ray powder diffraction, FTIR, Raman spectroscopy, BET surface area, CO chemisorption and NH3-Temperature-programmed desorption methods. The characterization results reveal the presence of well dispersed Pt metallic phase and Keggin structure of HPAs on support. The catalytic performance during glycerol hydrogenolysis is well correlated with Pt dispersion and the acidic properties of catalysts. Among the tested catalysts, it was found that Pt–PTA/ZrO2 exhibited excellent selectivity to propanols (98%) with total glycerol conversion at 230 °C. A detailed study was made on the effect of various reaction parameters such as the influence of reaction temperature, reduction temperature, glycerol concentration, hydrogen flow rate, feed flow rate and HPA loading to unveil the optimized reaction conditions. Reaction temperature was observed to have a significant effect on the glycerol conversion and product selectivity. The spent catalysts were also characterized by the X-ray diffraction, NH3-TPD and SEM analysis to investigate the changes in catalytic performance and causes of catalyst deactivation.