Reduction kinetics of bromate with thiocyanate and dynamics of the closed system BrO3-/SCN-/HClO4

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Title:Reduction kinetics of bromate with thiocyanate and dynamics of the closed system BrO3-/SCN-/HClO4
Creators:
Valent, Ivan
Adamčíková, Ľubica
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 56, 8, pp. 1565-1574

Abstract

The reduction kinetics of bromate ions with thiocyanate was studied polarographically and the dynamics of the BrO<sub>3</sub><sup>-</sup>/SCN<sup>-</sup> system was studied spectrophotometrically in the medium of perchloric acid in both cases. The reduction in the presence of an at least ten-fold excess of SCN<sup>-</sup> ions is governed by the kinetics equation – d[Br(V)]/d<i>t</i> = <i>a</i>[Br(V)][SCN<sup>-</sup>][H<sup>+</sup>]<sup>2</sup>/(1 + <i>b</i>[SCN<sup>-</sup>]), where <i>a</i> = 19.2 ± 0.9 mol<sup>-3</sup> dm<sup>9</sup>, <i>b</i> = 4.4 ± 0.5 mol<sup>-l</sup> dm<sup>3</sup> at 20°C. A mechanism was proposed, based on the transfer of oxygen atom from HBrO<sub>3</sub> to SCN<sup>-</sup> ion. The dynamic system BrO<sub>3</sub><sup>-</sup>/SCN<sup>-</sup>/HClO<sub>4</sub> is non-monotonous in character. According to the conditions, the production of bromine has a sigmoidal course preceded by a lag phase or the bromine concentration passes through a maximum.

Title:Reduction kinetics of bromate with thiocyanate and dynamics of the closed system BrO3-/SCN-/HClO4
Creators:
Valent, Ivan
Adamčíková, Ľubica
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:56
Number:8
Page Range:pp. 1565-1574
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19911565UNSPECIFIED
ID Code:5081
Item Type:Article
Deposited On:22 Feb 2010 11:30
Last Modified:22 Feb 2010 10:30

Citation

Valent, Ivan; Adamčíková, Ľubica (1991) Reduction kinetics of bromate with thiocyanate and dynamics of the closed system BrO3-/SCN-/HClO4. Collection of Czechoslovak Chemical Communications, 56 (8). pp. 1565-1574. ISSN 0010-0765

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