Gas phase dehydration of glycerol over, lanthanum-modified beta-zeolite

DALLA COSTA, B.O.; M. A. PERALTA, M.A. ULLA, C. A. QUERINI; QUERINI, C.A..

APPLIED CATALYSIS A-GENERAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2014 vol. 472 p. 53 - 63

0926-860X

Glycerol dehydration to acrolein was studied using beta zeolites. Three catalysts were used, the parentcatalyst in the protonic form (H-B), and this catalyst after two ion exchanges, both with lanthanumnitrate (LCL-B) and one with lanthanum nitrate and the second with ammonium nitrate (LCH-B). Thecatalysts were characterized by XRD, XPS, FTIR with pyridine adsorption, pyridine TPD, BET, SEM, ICP,and pulses of 1-butene. Coke was characterized by TPO. Activity tests were carried out in gas phase. It wasfound that LCH-B and H-B catalysts had similar density of acid sites, but the strength distribution wasdifferent, having the former a higher proportion of medium-strength acid sites. Because of this, a betterperformance in glycerol dehydration was displayed by this catalyst. The changes in acidity were due tothe generation of new acid sites that occurred during the preparation, forming acid silanols attachedto silica-reach and alumina-reach species. Coke was rapidly formed on the three catalysts, completelyblocking the pores. Therefore, after a short time on oil, only the external surface is available for thereaction. Nevertheless, reasonable conversion and stability was obtained with LCH-B catalyst.