Properties and Evaluation of Azo Acid Dyes Based From 2-Aminothiophene on Chrome Tanned Leather and Nylon 6,6 Substrate

Abstract

A series of new azo acid dyes have been synthesized in moderate yield by diazotizing 2-amino-thiophene 
and coupling with R,H,J and ɣ acid. The dyes were characterized by spectroscopic studies. The dyeing 
capabilities were assessed by applying them on chrome tanned leather and nylon 6,6 substrates. The dyes 
were found to produced shades of red, dark blue and dark maroon. The synthesized dyes gave a maximum 
absorption within the UV- visible region with λmax515-597 nm and molar extinction coefficient ranging 
from (3.217-4.221 x 104 l/mol-1 cm-1). The chrome tanned leather gave a wash fastness rating ranging from  
3(good) 4(very good) to 5(excellent) respectively, and nylon 6,6 gave a wash fastness rating ranging from 
4( very good ) to 5(excellent) fastness properties and the light fastness properties of chrome tanned leather 
gave a fastness rating 4(moderate), 5(good), 6(very good) and 7 (excellent) and rubbing fastness rating 4( 
very good) to 5(excellent) on both substrates. The synthesized azo acid dyes derived from 2
aminothiophene exhibit promising dyeing performance and fastness properties, demonstrating their 
potential suitability for application on both chrome tanned leather and nylon 6,6 substrates.