Investigation of alkaline hydrolysis of phthalimide-based azo dye and its application to after-treatment optimisation for high-fastness dyeing of polyesters

摘要

4-Amino-N-methylphthalimide was prepared from phthalimide for use as a diazo component and was coupled with N,N-Diethylaniline to produce a phthalimide-derived monoazo disperse dye. The pseudo first-order kinetics were confirmed by analyzing the dye hydrolysis under alkaline conditions using high performance liquid chromatography, and the optimal dyeing pH and alkali-clearing conditions were proposed. The synthesised phthalimidyl disperse dyes exhibited excellent colour fastness with a mild alkaline after-treatment instead of reduction clearing which results in a high biological oxygen demand and pH in conventional disperse dyeing wastewater.