Synthesis and Application of Hetaryl Disazo Disperse Dyes Derived from 2-Amino-5-Mercapto-1,3,4-Thiadiazole and 3-Chloroaniline on Synthetic Polymer-Fibres

The use of polyester fabrics in automotive upholstery has created a need for disperse dyes of exceptionally high sublimation and light fastness to withstand extended exposure to light and heat. Thus, in an attempt to find new disperse dyes of high fastness to sublimation and light, we report here the synthesis and evaluation of their fastness properties on polyester fabrics and nylon 66 fabrics. The synthesis of the dyes was carried out by diazotisation of the 2-amino-5-mercapto-1,3,4-thiadiazole in an acid medium and coupling with 3-chloroaniline to afford an intermediate. This intermediate was also subjected to diazotisation and coupling reactions with various couplers to give disazo disperse dyes. All the dyes exhibited outstanding washing, sublimation, perspiration and good to very good light fastness ratings on polyester and nylon 66 fabrics. The dye structures were characterized, using proton and carbon-13 nuclear magnetic resonance (1H NMR and 13C NMR) IR, and ultraviolet – visible analyses. Keywords: Hetaryl azo dyes, spectral properties, dye application, fastness propertie