Hierarchically structured ZSM-5 obtained by desilication as new catalyst for DME synthesis from methanol

A new type of micro–mesoporous materials with properties of ZSM-5 zeolite was tested as catalysts for the synthesis of dimethyl ether (DME) from methanol. The catalytic performance of ZSM-5 was improved by generation of mesoporosity using desilication method (alkaline leaching of framework Si). It was shown that controlled modification of the porous structure and acidity of the zeolitic samples strongly influences their catalytic activity, selectivity and stability in the process of DME synthesis. Desilication of ZSM-5 zeolite resulted in a development of the mesoporous structure and enhancement of its acidity, what was confirmed by N2-sorption measurements, IR-DRIFT spectroscopy and NH3-TPD. Desilicated zeolite samples exhibited higher catalytic activity and stability in the process of DME synthesis in comparison to parent ZSM-5. Moreover, micro–mesoporous zeolites were more resistant for poisoning by coke deposits in comparison to conventional ZSM-5 catalyst.