Abstract

Four monoazo acid dyes were synthesised, characterized and applied on chrome-tanned leather. The azo compounds were synthesised via diazotization of phenylhydrazine and coupled with H-acid, Tobias acid, J-acid and R-acid to give four different mono azo dyes. The dyes were characterized via analytical techniques such as melting point, UV-visible, and infrared spectroscopy. The dyes exhibited well-defined melting points ranging from 255-268 ℃ with characteristic colours ranging from purple to brown. The dyes absorbed within the visible region of the electromagnetic spectrum in ethanol as a solvent with a wavelength range of 396-534 nm. The infrared spectroscopy confirmed some functional groups such as NH/OH, C=O, S=O, C-H and -N=N- respectively. The fastness tests of the dyed chrome tanned leather showed excellent fastness properties to wash, rub and a good light fastness rating.