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Mechanism of Selective Oxidation and Ammoxidation of Propene on Bismuth Molybdates from DFT Calculations on Model Clusters

Jang, Yun Hee and Goddard, William A., III (2002) Mechanism of Selective Oxidation and Ammoxidation of Propene on Bismuth Molybdates from DFT Calculations on Model Clusters. Journal of Physical Chemistry B, 106 (23). pp. 5997-6013. ISSN 1520-6106. https://resolver.caltech.edu/CaltechAUTHORS:20170619-065026061

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Abstract

In this paper, we use first principles quantum mechanical methods (B3LYP flavor of Density Functional Theory) to examine the mechanism of selective oxidation and ammoxidation of propene by BiMoO_x catalysts. To do this, we use finite clusters chosen to mimic likely sites on the heterogeneous surfaces of the catalysts. We conclude that activation of the propene requires a Bi(V) site, whereas all subsequent reactions involve di-oxo Mo(VI) sites adjacent to the Bi. We find that two such Mo sites are required for the most favorable reactions. These results are compatible with current experimental data. For ammoxidation, we conclude that ammonia activation would be easier on Mo(IV) rather than on Mo(VI). Ammonia would be activated more easily for more reducing condition. Because ammonia and propene are reducing agents, higher partial pressures of them could accelerate the ammonia activation. This is consistent with the kinetic model of ammoxidation proposed by Grasselli and co-workers that imido sites (Mo═NH) are more abundant in higher partial pressures of feed. Our calculations also indicate that allyl groups produced as a result of the hydrogen abstraction from propenes would be adsorbed more easily on imido groups (Mo═NH) than on oxo groups (Mo═O) and that the spectator oxo effect is larger than spectator imido effect. Thus, we propose that the best site for ammoxidation (at least for allyl adsorption) is the imido group of the “oxo-imido” species.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp0208081DOIArticle
http://pubs.acs.org/doi/abs/10.1021/jp0208081PublisherArticle
ORCID:
AuthorORCID
Goddard, William A., III0000-0003-0097-5716
Additional Information:© 2002 American Chemical Society. Received 26 March 2002. Published online 18 May 2002. Published in print 1 June 2002. We thank Asahi Chemical Ind. Co., Ltd., Fuji, Shizuoka 416-8501, Japan for providing funding for this project and Dr. Terumasa Yamasaki of Asahi Chemical for helpful comments. Some support was provided by the ARO/MURI (DAAD 19-01-1-0517). We also thank Dr. Bob Grasselli and Dr. Jim Burrington for many helpful discussions over the years. The facilities of the MSC are also supported by grants from NSF-MRI, DOE-ASCI, ARO/MURI, Chevron, 3M, Beckman Institute, Seiko-Epson, Dow, Avery-Dennison, Kellogg, NSF-CHE, NIH, and ARO/DURIP.
Funders:
Funding AgencyGrant Number
Asahi Chemical Ind. Co. Ltd.UNSPECIFIED
FujiUNSPECIFIED
Shizuoka416-8501
Army Research Office (ARO)DAAD 19-01-1-0517)
NSFUNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
ChevronUNSPECIFIED
3MUNSPECIFIED
Caltech Beckman InstituteUNSPECIFIED
Seiko-EpsonUNSPECIFIED
DowUNSPECIFIED
Avery-DennisonUNSPECIFIED
KelloggUNSPECIFIED
NIHUNSPECIFIED
Issue or Number:23
Record Number:CaltechAUTHORS:20170619-065026061
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20170619-065026061
Official Citation:Mechanism of Selective Oxidation and Ammoxidation of Propene on Bismuth Molybdates from DFT Calculations on Model Clusters Yun Hee Jang and William A. Goddard III The Journal of Physical Chemistry B 2002 106 (23), 5997-6013 DOI: 10.1021/jp0208081
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78311
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:19 Jun 2017 16:29
Last Modified:03 Oct 2019 18:07

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