Base treated H-mordenite as stable catalyst in alkylbenzene transalkylation

Abstract

The effect of post treatment methods on the pore structure of hierarchical mordenite and its catalytic performance in transalkylation of heavy alkylbenzenes were studied. While the catalytic stability of H-mordenite deteriorated with dealumination by acid or steam treatment, it was improved with desilication by base post treatment. Comparing to the state-of-the-art Pt/mordenite catalysts, the desilicated H-mordenite showed comparable stability giving the best benzene product purity at lower hydrogen and energy consumption and presented the greenest solution. The improved stability is attributed to an enhanced diffusion behavior in the meso-micro hierarchical structure. As confirmed by NMR and sorption data, base treatment can preferentially remove framework silica and re-insert octahedral aluminium into the mordenite structure simultaneously, through which it created enlarged mesopores and defected 12-MR micropores to form a hierarchical porous structure.