Catalysts for glycerol hydrogenolysis
Transcription
Catalysts for glycerol hydrogenolysis
Catalysts for glycerol hydrogenolysis: production of glycols from biomass derivatives Daniela Zanchet Instituto de Química, UNICAMP, Campinas, SP [email protected] 2007/51754-4 - PITE project as part of FAPESP-OXITENO and BIOEN initiative Term: 10/2008-03/2011 Team LNLS-CNPEM (ABTLuS) Oxiteno Ind. & Com. Ltda Dr. Cristiane B. Rodella Dr. Valéria P. Vicentini Dr. Silvia Fernanda Moya Ms. Carla M. S. Queiroz Dr. Ricardo J. Chimentão Lígia S.Rodrigues (tech. – TT2) Rafael A. Ferreira (tech. - TT2) Collaborators Dr. Roberto Rinaldi (Max-Planck) Prof. Victor Teixeira (UFRJ) Goal Glycerol major by-product of biodiesel production (low cost, large volume) . New opportunites (“glycerochemistry”) Glycerol Hydrogenolysis H2 H2 Goal Evaluation and development of heterogeneous catalysts (industrial application at OXITENO); Understanding of the kinetics and mechanism of the catalytic hydrogenolysis - Selectivity to EG or 1,2-PG Correlation with physical and chemical properties of the catalysts Model catalysts based on nanoscience approach Scientific challenges Glycerol hydrogenolysis is a complex chemical reaction → parallel pathways and reactions (reforming, WGS, methanation) -H2O H +H2 H A. Torres et al., Ind. Eng. Chem. Res. , 2010; C.J. Mota et al. Quimica Nova, 2009. Coupled reactions Reforming+ hydrogenolysis Roy et al, Cat. Today, 156 (2010), 31; Yin et al., Green Chem., 11 (2009), 1514. Scientific challenges For the reaction: Coupled reactions - maximize activity and selectivity to either EG and 1,2-PG; minimize the formation of gas products (conc., T, P) For the catalyst: Tuning catalysts properties (electronic configuration, particle size, defects, metal dispersion, etc.): active sites that enhance different type of bond cleavage: C-C, C-O, C-H, O-H Keeping in mind… to find the best compromise considering the specific needs of OXITENO Infrastructure at LSQ-LNLS High pressure reactor installed in an explosionproof room – similar to OXITENO set-up Gas chromatograph Fixed bed reactor set-up Integration and automation of reactor operation software and safety interlocks Catalysts Catalysts development and testing: Conventional catalyst: Ru/C best catalyst to promote C-C cleavage, but high cost and severe catalytic reaction conditions Alternatives : •Ni Raney low cost and mild catalytic reaction condition (no need of external H2) • Tungsten carbides supported on carbon platinum-like catalytic behavior, efficient for cellulose hydrogenolysis, low cost but severe catalytic reaction conditions •Model catalysts based on colloidal nanoparticles 5% Ru/C Samples: 5% Ru/C (Acros) 5% Ru/C – LNLS (dry impregnation RuCl3) 1wt.% glycerol, 110 mg of catalyst, 4MPa of H2 Raney Ni catalyst Raney Ni Ni-Al alloy Al Ni2Al3 NiAl3 Samples: Raney Ni 3111A - Grace Co. (1% Mo) Raney Ni 2800 - Grace Co. Raney Ni - LNLS 10wt.% glycerol, 1,67g of catalyst C.B. Rodella, G. Kellermann, M.S.P. Francisco, M.H. Jordão, D. Zanchet, Ind. Eng. Chem. Res. 2008, 47, 8612. Raney Ni x Ru/C Both produce large amounts of gas (CO2, CH4) Raney Ni →1,2-PG Ru/C → EG H2 pressure favors EG. Raney Ni favors the reforming of glycerol Selectivity to EG decreases with time Degradation of EG is more pronounced in Ru/C The results pointed out that high selectivity to EG will be difficult to be achieved in batch reactor (Temperature transient at the beginning). Carbon support Dependence on the carbon support supplier Ru/C C-A C-B C-MERCK 26,0 23,7 30,7 EG 19,4 29,6 27,2 1,2-PG 13,5 15,3 11,9 CO2 1,6 0,4 - CH4 59,1 43,5 48,4 Others 6,4 11,2 13,5 Selectivity to liq. (%) 34,0 50,2 44,1 Conversion (%) Selectivity (%) *All samples presented traces of acetol . P.Trecco (Undergraduate project) Tungsten Carbides -Synthesis Improves surface area Temperature Programmed Carburization (TCP) WO3 WOx (0x3) W W2C WC 100 – 200 ml.min-1 pure H2 or 10%CH4/H2 W amorphous 9000C 8500C W2C C + bcc 7000C Temperature WC or hcp hex Promoters like Ni, Fe and Co decrease carburization temperature and improve catalytic activity Structural characterization XRD - in situ Furnace θ X Ray beamline WxC Structural and surface properties - dependent on the gas used in the carburization process and presence of Ni H2 → well crystallized W2C, carbon deposition and low conversion 20%CH4/H2 → smaller particles, less carbon deposition and higher conversion. Ni → carburization at lower temperature (100 K) Glycerol hydrogenolysis favors 1,2-PG (acetol pathway). Colloidal nanoparticles Ru-NPs NiPt-NPs Preliminary results showed low activity in the hydrogenolysis of propane Collaboration with Dr. C.S. Claro and F. Requejo - Univ. La Plata, Argentina Conclusion Evaluation of catalysts for hydrogenolysis of glycerol: EG is favored at short times. No satisfactory results were found with batch reactor Selectivity to gas products excessively high. Raney Ni - favors H* generation through glycerol reforming Ru/C – higher selectivity to EG WxC - carburization with CH4/H2 and presence of Ni improve the performance. Selectivity towards 1,2-PG Influence of the C support (?) Other results: invited talk at CBCAT/11, CatBior/11, 2 articles in preparation Acknowledgments Dr. Cristiane Rodella (WxC - LNLS) Dr. Silvia Moya (CTBE) Dr. Ricardo Chimentão Ligia Rodrigues Rafael Ferreira LNLS staff Dr. Valéria Vicentini Carla Queiroz Oxiteno staff Prof. Jose Maria C. Bueno Debora M. Meira Renata U. Ribeiro Dr. Cecilia Claro (ULP) Dr. Felix Requejo (ULP) Dr. Roberto Rinaldi (Max-Planck) Prof. Victor Teixeira (UFRJ) Dr. Jose L. Zotin (CENPES) Sandra Chiaro (CENPES) Funding: FAPESP, Oxiteno, LNLS