Abstract

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A series of new mono azo dyes have been synthesized in moderate yield from diazotization of thiophene and coupling with R, H, J and ϒ acid. The dyes were characterized by spectral studies. The dyeing potentials were assessed by applying them on chrome tanned leather and nylon 6,6 substrates. The dyes were found to give shade 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) and the infra-red spectra showed peaks at 1582-1421cm1 (due to azo group (N=N) stretching vibration), at 3400 – 3200 cm-1 due to (OH&NH) medium & broad stretching vibration ), at 2830-26-95cm- 1 (due to aromatic group ( C-H) stretching vibration) , at 1760-1640 cm-1 (due to carbonyl group (C=O) stretching vibration), at 1342-1266 cm-1 (due to aromatic amine group (C-N) stretching vibration) and at 2260-2222 cm-1 ( due to nitrile ( C≡N ) stretching vibration). The dye exhibited good depth, affinity, levelling and brightness properties on the substrates. The dye gave a good percentage exhaustion on nylon 6.6 and on chrome tanned leather substrates ranging from (78-87%) and (63-75%) respectively. The chrome tanned leather gave a wash fastness rating ranging from (3 -5) good, very good to excellent respectively and nylon 6,6 gave a wash fastness rating ranging from (4-5) very good to excellent fastness properties and the light fastness properties of chrome tanned leather gave a fastness rating (4-7) moderate, good, very good and excellent and rubbing fastness rating (4-5) very good to excellent on both substrates. The good shades observed may be due to better substantivity on chrome tanned leather and nylon 6,6 fabrics

Keywords: Monoazo dyes , Synthesis , Exhaustion , Fastness properties, Diazotization