Synthesis of disazo disperse dye compounds derived from 4-bromoaniline and 3-aminophenol as potential near infra-red absorbers.

In attempt to find new near infra-red absorbing azo compounds, the synthesis and characterization of six disazo compounds are reported. The azo compounds were synthesized via diazotization of 4-bromoaniline and coupled with 3-aminophenol to afford 4-bromophenylazo-41-amino-2-hydroxybenzeneazo dye intermediate. This intermediate was further diazotized and coupled with various aryl-amine and phenolic couplers to give a series of disazo disperse dyes. The UV-VIS spectral properties of the dyes were evaluated and some of the dye derivatives bearing electron withdrawing groups in their couplers showed absorptions at 772nm to 786nm in the near infra-red region in dimethylformamide solution. This, in addition to their relatively high thermal stability would enhance their use as potential organic photoconductors. The results of the fastness tests of the dyes on nylon fiber and polyester fiber showed excellent sublimation, washing, good rubbing and light fastness ratings. This also indicates that the azo compounds could be of commercial importance in the textile industry. The dyes were further characterized using proton nuclear magnetic resonance (1HNMR), carbon- 13 nuclear magnetic resonance (13CNMR) and infra- red (IR) analyses. Keywords: Disazo dyes, spectral properties, disperse dyes, fastness, nylon fiber, polyesterfiber

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