zeolite-catalyzed hydrocarbon formation from methanol density functional simulationszeolite-catalyzed从甲醇烃形成密度功能的模拟.pdfVIP

Int. J. Mol. Sci. 2002, 3, 423-434 International Journal of Molecular Sciences ISSN 1422-0067 © 2002 by MDPI /ijms/ Zeolite-Catalyzed Hydrocarbon Formation from Methanol: Density Functional Simulations ** Niranjan Govind , Jan Andzelm, Kurt Reindel, George Fitzgerald Accelrys Inc., 9685 Scranton Road, San Diego, California 92121, USA **Author to whom correspondence should be addressed. Email: nxg@ Received: 16 October 2001 / Accepted: 31 January 2002 / Published: 25 April 2002 Abstract: We report detailed density functional theory (DFT) calculations of important mechanisms in the methanol to gasoline (MTG) process in a zeolite catalyst. Various reaction paths and energy barriers involving C-O bond cleavage and the first C-C bond formation are investigated in detail using all-electron periodic supercell calculations and recently developed geometry optimization and transition state search algorithms. We have further investigated the formation of ethanol and have identified a different mechanism than previously reported [1], a reaction where water does not play any visible role. Contrary to recent cluster calculations, we were not able to find a stable surface ylide structure. However, a stable ylide structure built into the zeolite framework was found to be possible, albeit a very