Conversion of methanol to hydrocarbons: How zeolite cavity and pore size controls product selectivity

Abstract

Liquid hydrocarbon fuels play an essential part in the global energy chain, owing to their high energy density and easy transportability. Olefins play a similar role in the production of consumer goods. In a post-oil society, fuel and olefin production will rely on alternative carbon sources, such as biomass, coal, natural gas, and CO 2. The methanol-to-hydrocarbons (MTH) process is a key step in such routes, and can be tuned into production of gasoline-rich (methanol to gasoline; MTG) or olefin-rich (methanol to olefins; MTO) product mixtures by proper choice of catalyst and reaction conditions. This Review presents several commercial MTH projects that have recently been realized, and also fundamental research into the synthesis of microporous materials for the targeted variation of selectivity and lifetime of the catalysts. The active site of the methanol-to-hydrocarbons reaction has been identified as a hybrid site consisting of an organic molecule in close interaction with a Brnsted acidic proton on the zeolite lattice. With increasing internal volume, the organic intermediates change from alkenes via a mixture of alkenes and arenes to mainly arenes. Product selectivity reflects the site composition. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.