The Hydrolysis of Reactive Dyeings

Twelve reactive dyes were synthesised containing the same chromophore but different reactive systems and different bridge members. These dyes were applied to mercerised cotton at approximately standard depth and the effects on the dyeings of alkaline and acid hydrolysis were studied. Increasing reactivity of dichloro‐ and trichloro‐pyrimidyl dyes is accompanied by a growing tendency to acid and, more particularly, alkaline hydrolysis. The position at which saponification occurs depends on the nature of the bridge member. In a second series of dyes, various reactive systems were combined with the same chromophore through an imino group; no general relation between reactivity and tendency to hydrolysis could be established for these dyes.