Zeolite Catalyst ZSM-22 Can Convert Methanol to Hydrocarbons; Potential for Gasoline

2 July 2009

Researchers at the University of Oslo, Norway have found that the zeolite catalyst ZSM-22, previously believed to be inactive in the conversion of methanol to hydrocarbons, yields a unique hydrocarbon product spectrum.

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The discovery, which has potential implications for the production of cleaner transportation fuels from natural gas or biomass (via a methanol pathway), is reported in the inaugural issue of the journal ChemCatChem, published by Wiley.

One commercial pathway for the production of petrochemical products from carbonaceous feedstocks involves the methanol-to-hydrocarbons (MTH) reaction. As examples, ExxonMobil is developing and promoting its methanol-to-gasoline (MTG) process (earlier post) using a ZSM-5 catalyst, while UOP and Hydro are offering a methanol to olefins (MTO) process.

Owing to shape selectivity, the product from ZSM-22 is rich in branched C₅₊ alkenes, without the formation of aromatic products.

In summary, zeolite ZSM-22 is an active catalyst in the MTH reaction. Low feed rates and temperatures in the range 400–500 °C are required for appreciable conversion. The catalysts showed high selectivity for branched C₅₊-fraction alkene which could be used for the production of cleaner gasoline. Aromatic reaction centers required for initial alkene formation were found to reside inside the narrow channels of ZSM-22, and it is proposed that further conversion of methanol proceeds to a large extent via alkene methylation and cracking.

—Teketel et al. (2009)

Resources

• Shewangizaw Teketel, Stian Svelle, Karl-Petter Lillerud, Unni Olsbye (2009) Shape-Selective Conversion of Methanol to Hydrocarbons Over 10-Ring Unidirectional-Channel Acidic H-ZSM-22. ChemCatChem doi: 10.1002/cctc.200900057