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DFT Mechanistic Study of Methane Mono-Esterification by Hypervalent Iodine Alkane Oxidation Process

Fu, Ross and Nielsen, Robert J. and Liebov, Nichole S. and Goddard, William A., III and Gunnoe, T. Brent and Groves, John T. (2019) DFT Mechanistic Study of Methane Mono-Esterification by Hypervalent Iodine Alkane Oxidation Process. Journal of Physical Chemistry C, 123 (25). pp. 15674-15684. ISSN 1932-7447. https://resolver.caltech.edu/CaltechAUTHORS:20190528-110238542

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Abstract

Recent experiments report high yield (up to 40%) and selectivity (generally > 85%) for the direct partial oxidation of methane to methyl trifluoroacetate in trifluoroacetic acid solvent using hypervalent iodine as the oxidant and in the presence of substoichiometric amounts of chloride anion. We develop here the reaction mechanism for these results based on density functional theory calculations (at the M06-2X/6-311G**++/aug-pVTZ-PP level) of plausible intermediates and transition states. We find a mechanistic process that explains both reactivity as well as selectivity of the system. In this oxy-esterification (OxE) system, IO_2Cl_2– and/or IOCl_4– act as key transient intermediates, leading to the generation of the high-energy radicals IO2• and Cl• that mediate methane C–H bond cleavage. These studies suggest new experiments to validate the OxE mechanism.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acs.jpcc.9b04239DOIArticle
ORCID:
AuthorORCID
Nielsen, Robert J.0000-0002-7962-0186
Goddard, William A., III0000-0003-0097-5716
Gunnoe, T. Brent0000-0001-5714-3887
Groves, John T.0000-0002-9944-5899
Additional Information:© 2019 American Chemical Society. Received: May 4, 2019; Revised: May 25, 2019; Published: May 28, 2019. Author Contributions: All calculations were carried out by R.F., with strategies suggested by R.F., R.J.N., and W.A.G. Experimental work was carried out by NSL under mentorship by T.B.G. Critical guidance was provided by J.T.G. and T.B.G. The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. This research was sponsored by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office, under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The funding for this computational project came from various gifts to the Materials and Process Simulation Center (MSC) at Caltech. The computers used were funded from DURIP grants to the MSC. The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
Department of Energy (DOE)DE-AC05-00OR22725
Office of Naval Research (ONR)UNSPECIFIED
Army Research Office (ARO)UNSPECIFIED
Subject Keywords:DFT, methane, monooxidation, monooxygenation, iodine
Other Numbering System:
Other Numbering System NameOther Numbering System ID
WAG1340
Issue or Number:25
Record Number:CaltechAUTHORS:20190528-110238542
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190528-110238542
Official Citation:DFT Mechanistic Study of Methane Mono-Esterification by Hypervalent Iodine Alkane Oxidation Process. Ross Fu, Robert J. Nielsen, Nichole S. Liebov, William A. Goddard, III, T. Brent Gunnoe, and John T. Groves. The Journal of Physical Chemistry C 2019 123 (25), 15674-15684. DOI: 10.1021/acs.jpcc.9b04239
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:95813
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:28 May 2019 20:14
Last Modified:03 Oct 2019 21:16

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