Synthesis and characterization of mesoporous mordenite

Three methods were investigated to synthesize mesoporous mordenite. XRD, N-2 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 Brensted acid sites by n-propylamine TPD and Al-27 NMR showed that the mesoporous mordenite had less extra-framework aluminum and a large number of Brensted 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. (C) 2009 Elsevier Inc. All rights reserved.