Synthesis and Application of Some Alkali‐Clearable Azo Disperse Dyes Based on Naphthalimide Derivatives

A series of naphthalimide‐based alkali‐clearable azo disperse dyes containing a fluorosulfonyl group was synthesized. 4‐Fluorosulfonylaniline, 4‐fluorosulfonyl‐2‐nitroaniline and 6‐chloro‐4‐fluorosulfonyl‐2‐nitroaniline as the diazo components were prepared from N‐acetylsulfanilyl chloride and were subsequently coupled with 4‐hydroxy‐N‐3‐methoxypropyl‐1, 8‐naphthalimide. The synthesized dyes and their intermediates were characterized by the use of DSC, FTIR, ¹H NMR, ¹³C NMR, Mass spectroscopy and UV‐visible spectroscopic techniques. Spectrophotometric investigations of prepared dyes in different solvents were carried out in order to obtain their absorption maxima, molar extinction coefficients and solvatochromic effects. The obtained dyes were applied to polyester fabric by the HT method and exhibited good leveling, wash and sublimation fastnesses and moderate light fastness. The synthesized dyes showed that incorporated fluorosulfonyl group to these dyes can be converted to the dyes containing a water soluble sulfonate group in the relatively mild alkaline conditions.