THE EFFECT OF SUBSTITOENTS ON PROPERTIES OF MONOAZO DYES DERIVED FROM H-ACID

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Date
1994-05
Authors
OWETE, VALERIE OBIAJULU
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Abstract
A variety of azo dyes were synthesized based on H- acid (1- amino,8- naphthol, 3,6- disulphonic acid ) coupled to diazotised aniline and its substituted derivatives. Electron releasing substituents - acetyl, benzoyl and paratoluene sulphonyl groups - were introduced into the amine group of the coupling component and aniline derivatives containing various electron withdrawing groups were used as the diazo components. The structural features of the dyes synthesized were ascertained by the analysis of their individual I.R. (infrared) spectra, measured in paraffin. The effect of different substituent groups on the colour of the dyes synthesized were studied by measuring the relative change of wavelength of maximum absorption in distilled water, and the solvatochromic effects in dimethyl formamide. The fastness properties of the dyes on Nylon 6.6 (woven) were also investigated. Results obtained showed the N- paratoluene sulphonyl groups as having the highest electron releasing strength resulting in marked bathochromic shifts. Marked trends were not observed for the various diazo ring substituents due to the interplay of steric hindrance and non-planarity of dyes formed. N- benzoylated H- acid dyes showed high wash, perspiration and light fastness properties due to intra molecular aggregation. viii N- acetylated H- acid favoured high perspiration and light fastness properties due to weak electron releasing strength which increases the dye's inherent stability.
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Being a Thesis submitted to post graduate school in partial fulfilment of the requirements for the award of Master of Science (M.Sc) Degree in Textile Science and Technology, Ahmadu Bello University, ZARIA, Department of Textile Science & Technology, Faculty of Science, Ahmadu Bello University, Zaria. MAY 1994
Keywords
SUBSTITOENTS,, MONOAZO,, DYES,, DERIVED FROM H-ACID
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