Ian M. Hill, Y. S. Ng, A. Bhan
Jul 18, 2012
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0
Influential Citations
44
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Journal
ACS Catalysis
Abstract
The systematic investigation of 1-butene, trans-2-butene, cis-2-butene, and isobutene methylation with dimethyl ether (DME) over acidic zeolites FER, MFI, MOR, and BEA at low conversions ( 15:1) showed linear rate dependencies on butene pressure and no dependence on DME pressure. Such dependencies are consistent with the zeolite surface being predominantly covered by DME-derived species, which either directly reacts with butene species in the rate-determining step or through the formation and subsequent degradation of a coadsorbed complex. A comparison of rate constants for butene methylation across isomers over MFI and BEA shows that, in the absence of hydride shift, a 10-fold increase is observed for reactants capable of forming more substituted carbenium ion-like transition states, as predicted for carbocation mediated mechanisms. High cis-2-butene pressure experiments over BEA show linear dependencies of the butene methylation rate on butene pressure for olefin to DM...