Hydrogenolysis of glycerol over Ni, Cu, Zn, and Zr supported on H-beta (original) (raw)
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Selective Hydrogenolysis of Glycerol to 1, 2 Propanediol Over Cu–ZnO Catalysts
Catalysis Letters, 2008
A series of Cu-ZnO catalysts with varying Cu to Zn weight ratio are prepared by co-precipitation method. The catalysts were characterized by surface area, XRD, TPR and N 2 O chemisorption to measure Cu metal area. These catalysts were evaluated for hydrogenolysis of glycerol. The catalyst with Cu to Zn ratio of 50:50 is highly active under relatively low H 2 pressure. The catalysts are highly selective towards 1,2 propanediol ([93%). The glycerol conversion depends upon the bifunctional nature of catalyst where it requires both acidic sites and metal surface. The presence of sufficient amount with small particle size of ZnO and Cu are required for high conversion of glycerol and selectivity to 1,2 propanediol. Different reaction parameters are studied in order to optimize the reaction conditions.
Applied Catalysis A: General, 2015
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 (1propanol + 2-propanol) under normal atmospheric pressure. The Pt-HPA/ZrO 2 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 NH 3 -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/ZrO 2 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, NH 3 -TPD and SEM analysis to investigate the changes in catalytic performance and causes of catalyst deactivation.
Development of Catalyst for Hydrogenolysis of Glycerol to 1,3 - Propanediol
2012
Background of Study. 1 1.1.1 Biodiesel production and availability of glycerol 1 1.1.2 Hydrogenolysis of Glycerol to 1,3-propanediol 3 1.1.3 Catalyst 4 1.1 Problem Statement 4 1.2 Objective and Scope of Studies 5 CHAPTER 2: LITERATURE RE VIEW , 2.1 Introduction 2.2 Metal used as the catalyst 7 2.3 Reaction Solution 2.4 Reaction Condition 2.5 Presence of Second Metal 12 2.6 Effectof Catalyst Reduction Temperature 12 CHAPTER 3: METHODOLOGY 13 3.1 Preparation of supported metal catalysts 3.1.1 Catalyst preparation procedures 3.2 Catalyst Characterization 19 3.3 Catalytic Test and Analysis 21 CHAPTER 4: RESULTS AND DISCUSSION 23 4.1 Catalyst Characterization 23 4.1.1 Fourier Transformed Infrared (FTIR) 23 4.1.2 Temperature Program Reduction (TPR) 24 4.1.3 X-Ray Diffraction (XRD) 26 4.1.4 Field Emission Scanning ElectronMicroscope (FESEM) 27 vi 32 LIST OF APPENDICES
Organic Process Research & Development, 2010
A series of Cu or Ni monometallic and Cu-Ni bimetallic catalysts supported on γ-Al 2 O 3 were synthesized by incipient wetness impregnation method. X-ray diffraction results exhibited the formation of bimetallic Cu-Ni phase in the reduced Cu-Ni(1:1)/γ-Al 2 O 3 catalyst. Among the catalyst examined for hydrogenolysis of glycerol, bimetallic catalysts exhibited higher catalytic activity than monometallic catalysts due to synergetic effect of Cu-Ni bimetal. Cu-Ni(1:1)/γ-Al 2 O 3 catalyst displayed a maximum glycerol conversion of 71.6% with 92.8% selectivity to 1,2-propanediol at 210 °C and 4.5 MPa hydrogen pressure. The superior performance of Cu-Ni(1:1)/γ-Al 2 O 3 catalyst was attributed to the formation of bimetallic Cu-Ni phase, high active metal surface area, small Cu-Ni particle size, and high acidic strength of the catalyst. Stability and reusability of Cu-Ni(1:1)/γ-Al 2 O 3 catalyst was performed and detailed characterization results of fresh and used catalysts suggested that bimetallic Cu-Ni phase remained stable after reuses.
Cu–Zn–Al mixed oxides as catalysts for the hydrogenolysis of glycerol to 1,2-propanediol
Reaction Kinetics, Mechanisms and Catalysis, 2019
This study is aimed to compare Cu-Al-Zn catalysts prepared by different methods and their effectiveness in glycerol hydrogenolysis to 1,2-propanediol. The preparation methods were: co-precipitation and thermal decomposition of hydrotalcite, coprecipitation by KOH and thermal decomposition of the precipitate, sol-gel autocombustion method, oxalate-gel co-precipitation and thermal decomposition of the precipitate and finally, mechanical mixing of Cu, Zn, Al oxides. It was found that the activity of the catalysts correlates well with the size of Cu crystallites. The smaller Cu crystallites, the higher the activity. However, also the texture of the catalyst, which also depends on the preparation method, has an impact on the catalyst activity. On the other hand, no correlation between activity and acidity, as well as internal surface area was found.
Study of hydrotalcite-supported transition metals as catalysts for crude glycerol hydrogenolysis
Molecular Catalysis, 2019
Hydrotalcites containing Fe, Ni-, Zn-and Cu were synthesized by the coprecipitation method. These catalysts were characterized and employed for the hydrogenolysis of pure glycerol. The catalyst with the best performance (HDT-Cu) was used to carry out the hydrogenolysis of crude glycerol. The best yield (74.1%) for the real, low purity (62%) glycerol was obtained at 3.4 MPa of H 2 and 200°C for 24 h of reaction. The regeneration capacity of the catalysts was also studied in order to develop an economically feasible process for industrial application.
Organic Process Research & Development, 2016
Pt, Pd, Ni and Cu supported on HSiW/Al 2 O 3 catalysts were studied for the hydrogenolysis of glycerol. It was found that Pt is the best promoter for the production of 1,3-propanediol (1,3-PD) and 1-propanol (1-PO). Ni, a much cheaper metal, has fairly comparable reactivity to Pt while Cu does not show any activity for the production of 1,3-PD. The catalysts were characterized by XRD and NH 3-TPD. The strength of the acid sites affects the distribution of products. A reaction mechanism for a NiHSiW/Al 2 O 3 catalyst involving rate determining parallel dehydration of primary alcohol to produce acetal and of secondary alcohol to produce 3hydroxypropylaldehdye (3-HPA) was proposed. Hydrogenolysis of 1,3-PD is 15 times slower than that of 1,2-PD. Most of the 1-PO is derived from 1,2-PD. An optimal balance of acid sites of appropriate acid strength and hydrogenation sites will lead to a highly selective catalyst for the production of higher value sustainable chemicals from glycerol.
Hydrogenolysis of glycerol to obtain 1,2-propanediol on Ce-promoted Ni/SBA-15 catalysts
Applied Catalysis B-environmental, 2012
Metallic Ni (10 wt.%) supported on SBA-15 silica and promoted with cerium loading ranged between 2.5 and 10 wt.%, reduced at 723 K during 1 h, were used as catalysts in the hydrogenolysis of a glycerol aqueous solution (80 wt.%) at 473 K and 2.4 MPa of H 2 pressure. Whereas pure Ni catalyst mainly produces volatile products by C C hydrogenolysis reaction, the promoted cerium catalysts lead to the formation of 1,2-propanediol (1,2-PDO) as majority product. After 8 h of reaction the catalyst with 10 wt.% of Ni and 7.5 wt.% of Ce gives the maximum glycerol conversion and selectivity to 1,2-PDO, with yield of this substance of 24.2%/g of catalyst. The presence of cerium species is essential to produce 1,2-PDO. The effect of cerium oxide is to act as strong acid sites (TPD-NH 3), improve the metallic Ni dispersion (XRD, H 2 chemisorption and XPS) and to make more difficult their reduction (TPR). The stronger acidity suggests that the formation of acetol takes place easier in these catalysts and subsequently this intermediate is reduced by activated hydrogen from the nearby Ni metallic sites.