화학공학소재연구정보센터
Applied Catalysis A: General, Vol.562, 258-266, 2018
Mesoporous Al-promoted sulfated zirconia as an efficient heterogeneous catalyst to synthesize isosorbide from sorbitol
Mesoporous aluminum-promoted sulfated zirconia (named as mAl-SZ) was directly prepared by grind method, and firstly used to catalyze the solvent-free dehydration of sorbitol to isosorbide. The physicochemical properties of as-prepared catalysts were characterized by FT-IR, TGA, XRD, N-2 sorption, NH3-TPD and pyridine-infrared (IR) spectroscopy techniques in order to elucidate the relevance of the catalyst properties and the catalytic performance. It was found that the catalysts prepared by grind method possessed mesoporous structures with high surface area, pure tetragonal phase as well as high sulfur contents, which were advantage to eliminate diffusion limitation and generate abundant acidic sites, especially Bronsted acidic sites. Furthermore, aluminum promoters could contribute to the considerable increase of the strong acidic sites and ratio of Bronsted to Lewis acidic sites. Consequently, the mesoporous sulfated zirconia with 6 mol% Al-promoter (6Al-SZ) attained porous structure with improved acidic properties, thus showing the optimal catalytic behavior. The full sorbitol conversion with 73% isosorbide selectivity was achieved under milder conditions (175 degrees C, 2 h) than those of similar type of catalysts. In addition, the 6Al-SZ exhibited favorable reusability with insignificant drop in isosorbide yield during five reaction cycles.