Glycerol dehydration catalyzed by MWW zeolites and the changes inthe catalyst deactivation caused by porosity modification

MARIANA RODRIGUES; CHARITO I. VIGNATTI; TERESITA F. GARETTO; SANDRA PULCINELLI; CELSO SANTILLI; LEANDRO MARTINS

APPLIED CATALYSIS A-GENERAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 495 p. 84 - 91

0926-860X

tMembers of the layered MWW family, including microporous MCM-22, pillared MCM-36 anddelaminated ITQ-2 zeolites, were used as catalysts for the gas phase dehydration of glycerol. Thechemical, structural and surface properties of the catalysts were characterized by X-ray diffraction,N2adsorption?desorption isotherms, SEM, TEM, NH3-TPD and pyridine chemisorption followed by IRspectroscopy. The results clearly showed that the modified zeolites with designed mesopore structureenabled rapid diffusion and consequently improved the glycerol conversion. Characterization of the acidsites revealed that the relative abundance of Brønsted and Lewis acid sites influenced the efficiency of thecatalysis performed by these materials.13C NMR spectra of the spent catalysts confirmed that differencesin the nature and amount of carbonaceous deposits are related to the pore structures of the catalysts, withgreater formation of polyaromatic compounds inside zeolite pores, while polyglycols are preferentiallyformed at the external surfaces of the MCM-36 and ITQ-2 zeolites, as expected for the more exposedsheets.