Synthesis and application of monoazo disperse dyes based on asymmetric bisimide on polylactic acid fabrics

Abstract

A novel series of monoazo disperse dyes were prepared by diazotization of 6-amino-2-(5-methyl-1,3-dioxo-1,3-dihydro-2H-isoindol-2-yl)-1H-benzo[de]isoquinoline-1,3(2H)-dione and coupling with N, N-dialkyl anilines and naphthol derivatives. To this end, acenaphthene was nitrated and several reaction steps like oxidation, amination, imidation, reduction, diazotization and coupling were carried out. The synthesized intermediates and dyes were characterized using FTIR, ¹HNMR, ¹³CNMR and mass spectroscopy. The solvatochromic properties of the dyes were examined in solvents of different polarity and their molar extinction coefficient determined in DMF. The synthesized dyes were evaluated for their dyeing behaviour and fastness properties on Polylactic acid fabrics. The results showed that absorption maxima of the synthesized dyes was in the range of 450 nm to 612 nm while their molar extinction coefficient was in the range of 15,600 – 39,200 Lmol^-1cm^-1. Measurement of fastness properties showed that the dyes have very good wash fastness (4-5), very good perspiration fastness (4-5) and between moderate to very good light fastness (3-6). The dyes also demonstrated very good colour strength (6-28) which is an indication of good levelness and affinity for the fabrics.