Hydrolysis mechanism and kinetics of bis( halogeno-s-trazine) reactive dyes

Hydrolysis reaction of bis(halogeno-s-trazine) reactive dyes(including bismonochloro-strazine reactive dye Reactive Red KE-3B and bismonofluoro-s-trazine reactive dye Reactive Red LS-2G) were studied by means of reversed-phase ion-pair high performance liquid chromatography(HPLC).From some aspects such as hydrolysis mechanism of bis(halogeno-s-trazine) reactive dyes,qualitative analysis of chromatographic peak and calculation of kinetics parameters,the hydrolysis performance of the bismonochloro-s-trazine reactive dye Reactive Red KE-3B at 90 ℃,pH=11.0 and the bismonofluoro-strazine reactive dye Reactive Red LS-2G at 80 ℃,pH=11.0 were discussed,and hydrolysis rate constants of bis(halogeno-s-trazine) form and monohalogenomonohydroxybis-s-trazine form of dyes were determined.The reactivity of bismonofluoro-s-trazine reactive dye Reactive Red LS-2G was found to be 3.4 times as much as that of bismonochloro-s-trazine reactive dye Reactive Red KE-3B.The reaction of the first halogen atom in bis(halogeno-s-trazine) reactive dyes can result in the inactivation of the second halogen atom(i.e.reduction of reaction rate),so the reactivity of dyes were determined mainly by the first reaction step.