Synthesis and characterization of mesoporous mordenite

Abstract

Three methods were investigated to synthesize mesoporous mordenite. XRD, N2 physisorption, SEM, and TEM showed that the mordenite obtained by acid leaching followed by base leaching of a conventional mordenite is a crystalline mesoporous material with MOR framework. The higher diffusivity of toluene indicated that mesopores benefited molecule transport through the zeolite crystal. Measurement of the number of Brønsted acid sites by n-propylamine TPD and 27Al NMR showed that the mesoporous mordenite had less extra-framework aluminum and a large number of Brønsted acid sites, while the isomerization of 2-methyl-2-pentene indicated that the mesoporous mordenite possessed a higher reactivity than conventional mordenite. The mesoporous mordenite had a much higher catalytic activity than conventional mordenite in the alkylation of benzene with benzyl alcohol. At 353 K and under atmospheric pressure, the conversion of benzyl alcohol over hierarchical mesoporous mordenite was 100% in 3 h, whereas the conversion over conventional mordenite was less than 2%. Synthesis of mesoporous mordenite with amphiphilic organosilane and carbon as secondary template did not give real mesoporous mordenite. © 2009 Elsevier Inc. All rights reserved.