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Stepwise Oxidation of Aqueous Dicarboxylic Acids by Gas-Phase OH Radicals

Enami, Shinichi and Hoffmann, Michael R. and Colussi, Agustín J. (2015) Stepwise Oxidation of Aqueous Dicarboxylic Acids by Gas-Phase OH Radicals. Journal of Physical Chemistry Letters, 6 (3). pp. 527-534. ISSN 1948-7185 . http://resolver.caltech.edu/CaltechAUTHORS:20150317-091651504

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Abstract

A leading source of uncertainty in predicting the climate and health effects of secondary organic aerosol (SOA) is how its composition changes over their atmospheric lifetimes. Because dicarboxylic acid (DCA) homologues are widespread in SOA, their distribution provides an ideal probe of both aerosol age and the oxidative power of the atmosphere along its trajectory. Here we report, for the first time, on the oxidation of DCA(aq) by ·OH(g) at the air–water interface. We found that exposure of aqueous HOOC-R_n-COOH (R_n = C_2H_4, C_3H_6, C_4H_8, C_5H_10, and C_6H_12) microjets to ∼10 ns ·OH(g) pulses from the 266 nm laser photolysis of O3(g)/O_2(g)/H_2O(g) mixtures yields the corresponding (n–1) species O═C(H)-R_(n–1^-)COO–/HOOC-R_(n–1^-)COO^–, in addition to an array of closed-shell HOOC-R_n(-H)(OOH)-COO^–, HOOC-R_n(-2H)(═O)-COO–, HOOC-Rn(-H)(OH)-COO–, and radical HOOC-Rn(-H)(OO·)-COO– species. Oxalic and malonic acids, which are shown to be significantly less hydrophobic and reactive than their higher homologues, will predictably accumulate in SOA, in accordance with field observations.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/jz502432jDOIArticle
http://pubs.acs.org/doi/abs/10.1021/jz502432jPublisherArticle
http://pubs.acs.org/doi/suppl/10.1021/jz502432jPublisherSupporting Information
ORCID:
AuthorORCID
Hoffmann, Michael R.0000-0002-0432-6564
Colussi, Agustín J.0000-0002-3400-4101
Additional Information:© 2015 American Chemical Society. Received: November 17, 2014; accepted: January 21, 2015; published: January 21, 2015. 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 for stimulating discussions. M.R.H. and A.J.C. acknowledge support from the National Science Foundation (U.S.A.) Grant AC-1238977.
Funders:
Funding AgencyGrant Number
Kurita Water and Environment FoundationUNSPECIFIED
Japan Science and Technology Agency (JST) PRESTO programUNSPECIFIED
NSFAC-1238977
Subject Keywords:troposphere; photochemical aging; surfactant; HOx chemistry; amphiphiles; surface chemistry
Record Number:CaltechAUTHORS:20150317-091651504
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20150317-091651504
Official Citation:Enami, S., Hoffmann, M. R., & Colussi, A. J. (2015). Stepwise Oxidation of Aqueous Dicarboxylic Acids by Gas-Phase OH Radicals. The Journal of Physical Chemistry Letters, 6(3), 527-534. doi: 10.1021/jz502432j
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:55836
Collection:CaltechAUTHORS
Deposited By: Jason Perez
Deposited On:18 Mar 2015 04:21
Last Modified:18 Mar 2015 04:21

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