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In Situ Mass Spectrometric Detection of Interfacial Intermediates in the Oxidation of RCOOH(aq) by Gas-Phase OH-Radicals

Enami, Shinichi and Hoffmann, Michael R. and Colussi, Agustín J. (2014) In Situ Mass Spectrometric Detection of Interfacial Intermediates in the Oxidation of RCOOH(aq) by Gas-Phase OH-Radicals. Journal of Physical Chemistry A, 118 (23). pp. 4130-4137. ISSN 1089-5639. http://resolver.caltech.edu/CaltechAUTHORS:20140718-094835893

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Abstract

Products and intermediates of the oxidation of aqueous alkanoic acids initiated by gas-phase hydroxyl radicals, ·OH(g), at the air–water interface were detected by mass spectrometry in a novel setup under various experimental conditions. Exposure of submillimolar RCOOH (R = methyl, n-pentyl, n-heptyl) aqueous microjets to ~10 ns ·OH(g) pulses from the 266 nm laser flash photolysis of O_3(g)/O_2(g)/H_2O(g) mixtures yielded an array of interfacial species that were unambiguously and simultaneously identified in situ by online electrospray mass spectrometry. We found that peroxyl radicals R(−H)(COO^–)OO· react within 50 μs to produce alcohols R(−H)(COO^–)OH and carbonyls R(−2H)(COO–)═O via competitive Russell and Bennett–Summers mechanisms. We confirmed the formation of hydroperoxides R(−H)(COO^–)OOH in experiments performed in D_2O. To our knowledge, this is the first report on the prompt and simultaneous detection of products and peroxyl/peroxide intermediates in the heterogeneous oxidation of aqueous organics initiated by ·OH(g).


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jp503387eDOIArticle
http://pubs.acs.org/doi/abs/10.1021/jp503387ePublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/jp503387eRelated ItemSupporting Information
ORCID:
AuthorORCID
Colussi, Agustín J.0000-0002-3400-4101
Additional Information:© 2014 American Chemical Society. Publication Date (Web): May 19, 2014. Received: April 7, 2014. Revised: May 11, 2014. Published: May 19, 2014. S.E. is grateful to Kurita Water and Environment Foundation and the Japan Science and Technology Agency (JST) PRESTO program. S.E. also thanks Prof. Hiroshi Masuhara and Dr. Yosuke Sakamoto for stimulating discussions. M.R.H. and A.J.C. acknowledge support from the National Science Foundation (U.S.A.) Grant AC-1238977. The authors declare no competing financial interest.
Funders:
Funding AgencyGrant Number
Kurita Water and Environment FoundationUNSPECIFIED
Japan Science and Technology Agency (JST) PRESTO programUNSPECIFIED
NSFAC-1238977
Record Number:CaltechAUTHORS:20140718-094835893
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20140718-094835893
Official Citation:In Situ Mass Spectrometric Detection of Interfacial Intermediates in the Oxidation of RCOOH(aq) by Gas-Phase OH-Radicals Shinichi Enami, Michael R. Hoffmann, and Agustín J. Colussi The Journal of Physical Chemistry A 2014 118 (23), 4130-4137
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:47321
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:18 Jul 2014 17:11
Last Modified:09 Mar 2015 23:14

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