MCM-41-Type Mesoporous Silicas Modified with Alumina in the Role of Catalysts for Methanol to Dimethyl Ether Dehydration

Abstract

MCM-41-type mesoporous silicas were modified with alumina by the impregnation, co-condensation, and template ion-exchange (TIE) methods. The obtained materials were characterized with respect to their chemical composition (ICP-OES), textural parameters (low-temperature N2 sorption), structure (XRD), and surface acidity (NH3-TPD) and tested as catalysts of methanol to dimethyl ether (DME) dehydration in a flow microreactor system. The catalytic performance of the studied materials was analyzed with respect to their porous structure, as well as their density and the strength of their acid sites. It was shown that the performance of the studied catalysts depends on the contribution of the surface exposed aluminum species, as well as their aggregation. For the most active catalyst, the study of its catalytic stability under rection conditions was performed. It was shown that the catalyst can be effectively regenerated by the incineration of carbon deposits under air flow at 550 °C for 1 h.