F. Salehirad, Michael W Anderson
Dec 1, 1996
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0
Influential Citations
59
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Journal
Journal of Catalysis
Abstract
13C solid-state MAS NMR was used to probe the chemistry of a number of species involved in the methanol-to-hydrocarbon process over H-SAPO-34 molecular sieve at both high (573 K) and low (473–563 K) temperature ranges and at very low conversion (<0.1%). Isobutane was the only hydrocarbon product observed at 473 and 573 K. Evidence for the operation of a stepwise methylation reaction via surface-bound species derives from, first, the treatment of several samples with different loadings of methanol at 523–563 K and, second, when either [13C]methanol is coadsorbed with [12C]ethene over the catalyst or [12C]ethene is reacted with pre-[13C]methylated SAPO-34. The hydrocarbon products in these experiments were mainly isobutane and isopentane as well as methane, ethene, and propane. Based on these experimental findings, a number of mechanistic approaches concerning the very first stages of the reaction are discussed.