The methanol-to-olefin (MTO) process allows the conversion of methanol/dimethyl ether into olefins on acidic zeolites via the so-called hydrocarbon pool mechanism. However, the site and mechanism of formation of the first carbon-carbon bond is still a matter of debate. Here, we show from a combination of experiments and DFT calculations that the Lewis acidic Al sites on the 110 facet of g-Al2O3 can readily activate dimethylether to yield CH4, alkenes and surface formate species according to spectroscopic studies combined with computational approach. The carbon-carbon forming step as well as the formation of methane and surface formate involves a transient oxonium ion intermediate, generated by a H-transfer between surface methoxy species and coordinated methanol on adjacent Al sites. These results indicate that extra framework Al centers in acidic zeolites, which are associated with alumina, can play a key role in the formation of the first carbon-carbon bond, the initiation step of the industrial MTO process. References 1. A. Comas-Vives, M. Valla, C. Copéret and P. Sautet, ACS Cent. Sci., DOI: 10.1021/acscentsci.5b00226 (2015)

Carbon–carbon bond formation upon dimethylether activation on alumina

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.