Aromatic transformations over aluminosilicate micro/mesoporous composite materials

Abstract

Catalytic behavior of micro/mesoporous ZSM-5/MCM-41 composites were investigated in the transformation of 1,2,4-trimethylbenzene (TMB), meta-xylene transformation and in the cracking of 1,3,5-triisopropylbenzene (TIPB). The samples were characterized by XRD, TGA, SEM, nitrogen sorption and FTIR of pyridine adsorption. The composite materials exhibited exceptional catalytic performance compared with the microporous ZSM-5 in the transformation of 1,2,4-trimethylbenzene and m-xylene. In the cracking of 1,3,5- triisopropylbenzene, the composite materials showed higher activity as compared with the conventional Y-zeolite. The distinctive catalytic performance of these micro/mesoporous composite materials in the reactions studied was attributed to the excellent accessibility of the active sites provided by the mesopores for both reactant and product molecules. In the transformation of m-xylene, selectivity towards para-xylene over all catalysts under study follows the order: conventional ZSM-5 ≈ ZM41A1 < ZM41A2 < ZM41A3. © 2012 The Royal Society of Chemistry.