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Kinetics and Mechanism for the Redox Reaction between Hexaaquathallium(III) and Sulfur Dioxide in Acidic Aqueous Solution

Berglund, Johan; Werndrup, Pia and Elding, Lars Ivar LU (1994) In Journal of the Chemical Society. Dalton Transactions 1994(9). p.1435-1439
Abstract (Swedish)
Oxidation of dissolved sulfur dioxide, SO2·nH2O, HSO3– and SO32–, by hexaaquathallium(III) has been studied in acidic aqueous solution with ionic strength 1.0 mol dm–3 at 25 °C. The stoichiometry of the reaction has been determined: [Tl(H2O)6]3++ SO2(aq)+ 2H2O →[Tl(H2O)6]++ HSO4–+ 3H+. The kinetics has been studied by use of stopped-flow spectrophotometry under pseudo-first-order conditions with either SIV or TlIII in excess. The reaction is first order in both [SIV] and [TlIII] and has a complex [H+] dependence. The rate decreases with increasing [H+] in the range 0.1 < [H+] < 1.0 mol dm–3. The results are interpreted in terms of a reaction mechanism where sulfito complexes are formed by reaction between [Tl(H2O)6]3+ or... (More)
Oxidation of dissolved sulfur dioxide, SO2·nH2O, HSO3– and SO32–, by hexaaquathallium(III) has been studied in acidic aqueous solution with ionic strength 1.0 mol dm–3 at 25 °C. The stoichiometry of the reaction has been determined: [Tl(H2O)6]3++ SO2(aq)+ 2H2O →[Tl(H2O)6]++ HSO4–+ 3H+. The kinetics has been studied by use of stopped-flow spectrophotometry under pseudo-first-order conditions with either SIV or TlIII in excess. The reaction is first order in both [SIV] and [TlIII] and has a complex [H+] dependence. The rate decreases with increasing [H+] in the range 0.1 < [H+] < 1.0 mol dm–3. The results are interpreted in terms of a reaction mechanism where sulfito complexes are formed by reaction between [Tl(H2O)6]3+ or [Tl(H2O)5(OH)]2+ and HSO3–. These complexes decompose to the products [Tl(H2O)6]+ and HSO4– by intramolecular inner-sphere electron-transfer processes. The thallium(III) sulfito complexes are weak, as indicated by the absence of any transient absorbance peaks in the UV region. Potentiometric measurements of the oxygen concentration and spectrophotometric measurements showed that TlIII does not initiate a free-radical chain oxidation of SIV by dissolved oxygen. (Less)
Abstract
Oxidation of dissolved sulfur dioxide, SO2·nH2O, HSO3– and SO32–, by hexaaquathallium(III) has been studied in acidic aqueous solution with ionic strength 1.0 mol dm–3 at 25 °C. The stoichiometry of the reaction has been determined: [Tl(H2O)6]3++ SO2(aq)+ 2H2O →[Tl(H2O)6]++ HSO4–+ 3H+. The kinetics has been studied by use of stopped-flow spectrophotometry under pseudo-first-order conditions with either SIV or TlIII in excess. The reaction is first order in both [SIV] and [TlIII] and has a complex [H+] dependence. The rate decreases with increasing [H+] in the range 0.1 < [H+] < 1.0 mol dm–3. The results are interpreted in terms of a reaction mechanism where sulfito complexes are formed by reaction between [Tl(H2O)6]3+ or... (More)
Oxidation of dissolved sulfur dioxide, SO2·nH2O, HSO3– and SO32–, by hexaaquathallium(III) has been studied in acidic aqueous solution with ionic strength 1.0 mol dm–3 at 25 °C. The stoichiometry of the reaction has been determined: [Tl(H2O)6]3++ SO2(aq)+ 2H2O →[Tl(H2O)6]++ HSO4–+ 3H+. The kinetics has been studied by use of stopped-flow spectrophotometry under pseudo-first-order conditions with either SIV or TlIII in excess. The reaction is first order in both [SIV] and [TlIII] and has a complex [H+] dependence. The rate decreases with increasing [H+] in the range 0.1 < [H+] < 1.0 mol dm–3. The results are interpreted in terms of a reaction mechanism where sulfito complexes are formed by reaction between [Tl(H2O)6]3+ or [Tl(H2O)5(OH)]2+ and HSO3–. These complexes decompose to the products [Tl(H2O)6]+ and HSO4– by intramolecular inner-sphere electron-transfer processes. The thallium(III) sulfito complexes are weak, as indicated by the absence of any transient absorbance peaks in the UV region. Potentiometric measurements of the oxygen concentration and spectrophotometric measurements showed that TlIII does not initiate a free-radical chain oxidation of SIV by dissolved oxygen. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Thallium(III), Sulfur dioxide, Redox reaction, Kinetics, Stopped-flow, Reaction mechanism
in
Journal of the Chemical Society. Dalton Transactions
volume
1994
issue
9
pages
1435 - 1439
publisher
Royal Society of Chemistry
external identifiers
  • scopus:37049070095
ISSN
1472-7773
DOI
10.1039/dt9940001435
language
English
LU publication?
yes
id
8c266fe3-382b-4df2-8d42-8e909f001cb4
date added to LUP
2017-01-07 20:55:10
date last changed
2017-05-29 11:37:38
@article{8c266fe3-382b-4df2-8d42-8e909f001cb4,
  abstract     = {Oxidation of dissolved sulfur dioxide, SO2·nH2O, HSO3– and SO32–, by hexaaquathallium(III) has been studied in acidic aqueous solution with ionic strength 1.0 mol dm–3 at 25 °C. The stoichiometry of the reaction has been determined: [Tl(H2O)6]3++ SO2(aq)+ 2H2O →[Tl(H2O)6]++ HSO4–+ 3H+. The kinetics has been studied by use of stopped-flow spectrophotometry under pseudo-first-order conditions with either SIV or TlIII in excess. The reaction is first order in both [SIV] and [TlIII] and has a complex [H+] dependence. The rate decreases with increasing [H+] in the range 0.1 &lt; [H+] &lt; 1.0 mol dm–3. The results are interpreted in terms of a reaction mechanism where sulfito complexes are formed by reaction between [Tl(H2O)6]3+ or [Tl(H2O)5(OH)]2+ and HSO3–. These complexes decompose to the products [Tl(H2O)6]+ and HSO4– by intramolecular inner-sphere electron-transfer processes. The thallium(III) sulfito complexes are weak, as indicated by the absence of any transient absorbance peaks in the UV region. Potentiometric measurements of the oxygen concentration and spectrophotometric measurements showed that TlIII does not initiate a free-radical chain oxidation of SIV by dissolved oxygen.},
  articleno    = {4/00063C},
  author       = {Berglund, Johan and Werndrup, Pia  and Elding, Lars Ivar},
  issn         = {1472-7773},
  keyword      = {Thallium(III),Sulfur dioxide,Redox reaction,Kinetics,Stopped-flow,Reaction mechanism},
  language     = {eng},
  month        = {05},
  number       = {9},
  pages        = {1435--1439},
  publisher    = {Royal Society of Chemistry},
  series       = {Journal of the Chemical Society. Dalton Transactions},
  title        = {Kinetics and Mechanism for the Redox Reaction between Hexaaquathallium(III) and Sulfur Dioxide in Acidic Aqueous Solution},
  url          = {http://dx.doi.org/10.1039/dt9940001435},
  volume       = {1994},
  year         = {1994},
}