The Effect of Grafting Zirconia and Ceria onto Alumina as a Support for Silicotungstic Acid for the Catalytic Dehydration of Glycerol to Acrolein |
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Authors: | Dr. Muhammad H. Haider Dr. Carmine D'Agostino Dr. Nicholas F. Dummer Dr. Mick D. Mantle Prof. Lynn F. Gladden Prof. David W. Knight Dr. David J. Willock Dr. David J. Morgan Prof. Stuart H. Taylor Prof. Graham J. Hutchings |
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Affiliation: | 1. Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT (United Kingdom);2. Department of Chemical Engineering and Biotechnology, University of Cambridge, New Museums Site, Pembroke Street, Cambridge, CB2 3RA (United Kingdom) |
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Abstract: | The effect of ceria and zirconia grafting onto alumina (α and θ–δ phases) as supports for silicotungstic acid for the dehydration of glycerol to acrolein was studied. 30 % Silicotungstic acid (STA) supported on 5 % zirconia/δ,θ‐alumina was the best catalyst, producing 85 % selectivity to acrolein at 100 % glycerol conversion, and it showed stable activity without using oxygen as a co‐feed. The catalyst produced a STA of 90 g(acrolein) kg(cat)?1 h?1, which was greater than the STA simply supported on δ,θ‐alumina, which only demonstrated 75 % selectivity towards acrolein. The effect of grafting on the support material was investigated by means of nitrogen adsorption, ammonia temperature‐programmed desorption, thermogravimetric analysis, Raman spectroscopy, and powder X‐ray diffraction. A pulsed‐field gradient (PFG) NMR technique was also used to study diffusion processes associated with the catalysts. Diffusion studies of the grafted catalysts showed that zirconia contributes to the formation of more tortuous pathways within the pore structure, leading to the diminution of acid strength and making the catalyst less susceptible to coke formation. |
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Keywords: | acrolein glycerol heterogeneous catalysis NMR spectroscopy silicotungstic acid |
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