ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
A detailed kinetic study of the reaction of toluidine blue (tolonium chloride) (TB+ Cl-) with thiourea (TU) in aqueous hydrochloric acid solution is reported. The reaction was first order with respect to toluidine blue and the reductant and second order with respect to [H+]. Thiourea had a 2:1 stoichiometric ratio with TB+. Toluidine blue was reduced to a colorless base in two one-electron reduction steps and TU was oxidized to thioformamidinium ion, which dimerized rapidly to give stable dithioformamidinium ion. The energy parameters obtained for TB+-TU reaction were mean energy of activation (Ea′) = 26.7 ± 2.4 kJ M-1; enthalpy of activation (ΔH#) = 24.2 kJ M-1; frequency factor (A) = 1.04 × 104 M-3 s-1; and entropy of activation (ΔS#) = -176.35 J M-1 s-1. © John Wiley & Sons, Inc.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/kin.550241110
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