Main Article Content

Nonlinear Kinetics and Mechanism of Nile Blue Reaction with Acidic Bromate and with Aqueous Bromine


SB Jonnalagadda
NR Gollapalli

Abstract

Nile blue, a dye of the phenoxazine class follows complex kinetics during its reaction with bromate in acidic solutions. The reaction kinetics were investigated using photometric and potentiometric techniques and a stopped flow apparatus. Under excess acid and bromate concentration conditions, nile blue, (NB+) initially depletes very slowly. After an induction period, a swift reaction occurs. The overall reaction is NB+ + BrO3- react to P + CH3COOH + H+ + Br-, where P is the de-ethylated N-oxide derivative of nile blue. The rapid kinetics of the reaction of bromine direct with nile blue were also reported. A 11-step mechanism, consistent with the overall reaction dynamics and supported by simulations, is described. The role of various bromo- and oxybromo- species is discussed.

South African Journal of Chemistry Vol.54 2001: 41-59

Journal Identifiers


eISSN: 1996-840X
print ISSN: 0379-4350