REDUCTION OF TOLUIDINE BLUE BY STANNOUS ION AT LOW PH - KINETICS AND SIMULATIONS

A detailed kinetic study of the reaction between toluidine blue (tolon ium chloride) (TB + Cl-) and stannous chloride is carried out in aqueo us hydrochloric acid. The depletion kinetics of toluidine blue were sp ectrometrically monitored at 626 nm. The reaction had fractional order with respect to toluidine blue (one half), three halves with respect to Sn2+, and first-order dependence on H+ ion. Stoichiometric ratio be tween reductant and oxidant is 1:1. During the reaction Sn2+ is oxidiz ed to Sn4+ and toluidine blue is reduced to colorless base in two univ alent steps. (C) 1993 John Wiley & Sons, Inc.