Formation of positive ions and other primary species in the oxidation of sulphides by hydroxyl radicals

authored by: Marija Bonifačić, Hermann Möckel, Detlef Bahnemann, K. Dieter Asmus
Abstract: The oxidation of simple aliphatic sulphides [MeSMe. EtSEt. (CH₂)₄S] by hydroxyl radicals occurs via a complex reaction mechanism. The first step is addition of the OH· to sulphur to form R₂ṠOH radicals. At low sulphide concentrations (<10^-4M) R₂ṠOH rapidly eliminates H₂O to form a RSR(-H)·; radical which may be described by the mesomeric forms -CH-S̄- and -CH=Ṡ-. This radical is ultimately also formed at higher sulphide concentrations but via a different pathway. R₂ṠOH increasingly reacts with another R₂S molecule to form a short lived (R₂S)₂OH· radical complex which dissociates to (R₂S)₂⁺ and OH^-. The (R₂S)₂⁺ complex ion seems to be relatively stable and decays essentially via equilibration to the molecular cation R₂S⁺. This ion in its reaction with the solvent, OH^- ions, and through a bimolecular process with another R₂S⁺ cation is effectively deprotonated to form the RSR(-H)· radical. The reaction route at high concentration includes the formation of transient species with oxidizing properties; Fe(CN)₆^4- is rapidly oxidized by (R₂S)₂⁺ [and possibly (R₂S)₂OH·]. The RSR(-H)· radical partially disproportionates to negative and long lived (>1 ms) positive ions. The stable oxidation product, sulphoxide, has been identified.
External Organisation(s): Helmholtz-Zentrum Berlin für Materialien und Energie (HZB)
Type: Article
Journal: Journal of the Chemical Society, Perkin Transactions 2
Pages: 675-685
No. of pages: 11
ISSN: 1472-779X
Publication date: 1975
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: General Chemistry
Electronic version(s): https://doi.org/10.1039/P29750000675 (Access: Unknown)

BibTeX

@article{d06c856ea87143f5a0a469e5ea509e6f,
title = "Formation of positive ions and other primary species in the oxidation of sulphides by hydroxyl radicals",
abstract = "The oxidation of simple aliphatic sulphides [MeSMe. EtSEt. (CH2)4S] by hydroxyl radicals occurs via a complex reaction mechanism. The first step is addition of the OH· to sulphur to form R2ṠOH radicals. At low sulphide concentrations (<10-4M) R2ṠOH rapidly eliminates H2O to form a RSR(-H)·; radical which may be described by the mesomeric forms -CH-{\=S}- and -CH=Ṡ-. This radical is ultimately also formed at higher sulphide concentrations but via a different pathway. R2ṠOH increasingly reacts with another R2S molecule to form a short lived (R2S)2OH· radical complex which dissociates to (R2S)2+ and OH-. The (R2S)2+ complex ion seems to be relatively stable and decays essentially via equilibration to the molecular cation R2S+. This ion in its reaction with the solvent, OH- ions, and through a bimolecular process with another R2S+ cation is effectively deprotonated to form the RSR(-H)· radical. The reaction route at high concentration includes the formation of transient species with oxidizing properties; Fe(CN)64- is rapidly oxidized by (R2S)2+ [and possibly (R2S)2OH·]. The RSR(-H)· radical partially disproportionates to negative and long lived (>1 ms) positive ions. The stable oxidation product, sulphoxide, has been identified.",
author = "Marija Bonifa{\v c}i{\'c} and Hermann M{\"o}ckel and Detlef Bahnemann and Asmus, {K. Dieter}",
note = "Copyright: Copyright 2015 Elsevier B.V., All rights reserved.",
year = "1975",
doi = "10.1039/P29750000675",
language = "English",
pages = "675--685",
journal = "Journal of the Chemical Society, Perkin Transactions 2",
issn = "1472-779X",
publisher = "Chemical Society",
number = "7",
}