Effect Of Position of Substituents on the Exhaustion and Thermodynamic Parameters of 6 Monoazo Acid and Disperse Dyes on Nylon 6

Abstract

Six monoazo acid and disperse dyes were synthesized using compounds of aromatic amine by diazotizing sulphanilic acid, 4-nitroaniline, sulphanilic acid, and 3-aminophenol. The coupling components used were 1-naphthol and 2-naphthol. The different properties of the dyes such as molecular structure, molar extinction coefficient, and percentage exhaustion were determined. The thermodynamic parameters of the four dyes on nylon fabrics were also determined. The results showed that the dyes have very good extinction coefficient, thus can be of commercial significance. The standard affinities of the dyes on nylon varied between 8.59 kJmol^-1to 25.51 kJmol^-1implying very high equilibrium % exhaustion. The implication of the standard affinities is that dye with -Dm⁰ 25.51kJmol^-1 has the highest % exhaustion, which means that there are correlation between standard affinity of a dye on fabric and the equilibrium exhaustion.

Keywords: Monoazo acid, disperse dye, Diazotization, Exhaustion, Extinction coefficient, Thermodynamic parameters, Standard affinities