Development of Catalysts Based on Pentasil-Type Zeolites for Selective Synthesis of Lower Olefins from Methanol and Dimethyl Ether

Using an integrated physicochemical approach to the study of zeolites and catalysts, scientific foundations for the targeted synthesis of catalysts based on ZSM-5 type zeolites for selective production of lower olefins from methanol and dimethyl ether have been developed. The selective synthesis of the C-2= and C-3= olefins takes place on medium-strength acid sites. The domination of strong acid sites increases the extent of the secondary oligomerization, aromatization, and cracking reactions and intensifies the deactivation of the catalyst. The effects of reaction conditions (feed partial pressure and temperature) on the outcomes of the process have been investigated. High-efficiency Zn-containing catalysts based on modified pentasils and promoted with magnesium and phosphorus have been developed for C-2=-C-4= olefin synthesis. These catalysts compare well with the industrial catalyst used in the Lurgi process.