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Kinetics and mechanism of the oxidation of aquated sulfur dioxide by hydrogen peroxide at low pH

McArdle, James V. and Hoffmann, Michael R. (1983) Kinetics and mechanism of the oxidation of aquated sulfur dioxide by hydrogen peroxide at low pH. Journal of Physical Chemistry, 87 (26). pp. 5425-5429. ISSN 0022-3654. doi:10.1021/j150644a024. https://resolver.caltech.edu/CaltechAUTHORS:20150820-073728512

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Abstract

A stopped-flow kinetic study of the oxidation of sulfur dioxide by hydrogen peroxide was performed over the pH range 0.0-4.5. A rate expression of the following form was verified experimentally: d[S(VI)]/dt = k_lK_(a1)[H_2O_2][S(IV)](k_2[H^+] + /((k-l+ k2[H+]+ k_3[HA])/{k_(-1) + k_2[H^+]+ k_3[HA])(k_(al) + [H^+]) The following kinetic parameters at 15 ºC were determined: k_l = (2.6 ± 0.5) x 10^6 M^(-1) s^(-1), k_2/k_(-l) = 16 ± 4 M^(-1), k_2/k_3 = (5 ± 1) x 10^2 (HA = acetic acid), ΔH^*_1 = 37 ± 2 kJ mol^(-1), and ΔS^*_1 = 4 ± 4 J K^(-1) mol^(-1). The reaction proceeds via a nucleophilic displacement of HSO_3^- by H_2O_2 to form a peroxymonosulfurous acid intermediate which undergoes acid-catalyzed rearrangement to form product: SO_2.H_2O ⇌ HSO_3^- + H^+ (k_(al)), H_2O_2 HSO_3^- ⇌ HOOSO_2^- (k_1,k_(-1) HOOSO_2^- + HA → HA + HSO_4^- k_3. Application of the above rate expression to reactions occurring in hydrometeors is discussed.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1021/j150644a024DOIArticle
http://pubs.acs.org/doi/abs/10.1021/j150644a024PublisherArticle
ORCID:
AuthorORCID
Hoffmann, Michael R.0000-0001-6495-1946
Additional Information:© 1983 American Chemical Society. Received: January 21, 1983. Publication Date: December 1983. We are grateful to the US. Environmental Protection Agency (R808086-1) for providing financial support for this research and to the Sloan Foundation Fund administered by Caltech which provided the necessary instrumentation.
Funders:
Funding AgencyGrant Number
Environmental Protection Agency (EPA)R808086-1
Issue or Number:26
DOI:10.1021/j150644a024
Record Number:CaltechAUTHORS:20150820-073728512
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20150820-073728512
Official Citation:Kinetics and mechanism of the oxidation of aquated sulfur dioxide by hydrogen peroxide at low pH James V. McArdle and Michael R. Hoffmann The Journal of Physical Chemistry 1983 87 (26), 5425-5429 DOI: 10.1021/j150644a024
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:59779
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:20 Aug 2015 17:26
Last Modified:10 Nov 2021 22:25

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