화학공학소재연구정보센터
Journal of Molecular Catalysis A-Chemical, Vol.396, 282-289, 2015
Dehydration of glycerin to acrolein over H3PW12O40 heteropolyacid catalyst supported on silica-alumina
A series of tungstophosphoricacid (H3PW12O40) catalysts supported on silica-alumina (SA-X (X=0, 15,30, 50, 70, 85, and 100)) with different SiO2 content (X, mol%) were prepared, and they (H3PW12O40/SA-X) were applied to the gas-phase dehydration of glycerin to acrolein. The effect of support composition on the physicochemical properties and catalytic activities of H3PW12O40/SA-X catalysts was investigated. Total acidity and Bronsted acidity of H3PW12040/SA-X catalysts determined from pyridine-adsorbed in situ FT-IR spectroscopy measurements showed volcano-shaped trends with respect to SiO2 content. Among the catalysts, H3PW12O40/SA-50 exhibited the largest total acidity while H3PW12O40/SA-85 showed the largest Bronsted acidity. The results of Al-27 NMR spectroscopy analyses of H3PM12O40/SA-X (X=15, 30, 50, 70, and 85) catalysts clearly demonstrated that Bronsted acidity of the catalysts was proportional to the amount of Ally species. It was revealed that yield for acrolein increased with increasing Bronsted acidity rather than total acidity of H3PW12O40/SA-X catalysts. Among the catalysts tested, H3PW12O40/SA-85 with the largest Bronsted acidity showed the highest yield for acrolein. A synergistic effect between H3PW12O40 and SA-85 for H3PW12O40/SA-85 catalyst was also observed in the dehydration of glycerin to acrolein. Moreover, the catalytic performance of regenerated H3PW12O40/SA-85 catalyst was almost recovered compared to that of fresh H3PW12O40/SA-85 catalyst. (C) 2014 Elsevier B.V. All rights reserved.