World Journal of Applied Chemistry 2019; 4(4): 63-68 http://www.sciencepublishinggroup.com/j/wjac doi: 10.11648/j.wjac.20190404.14 ISSN: 2637-5966 (Print); ISSN: 2637-5982 (Online) Synthesis and Dyeing Properties of Acid Dyes Derived from 1-amino-2-naphthol-4-sulphonic Acid Olawale Olayinka Omotosho, Umar Salami Ameuru Department of Polymer and Textile Engineering, Ahmadu Bello University, Zaria, Nigeria Email address: To cite this article: Olawale Olayinka Omotosho, Umar Salami Ameuru. Synthesis and Dyeing Properties of Acid Dyes Derived from 1-amino-2-naphthol-4- sulphonic Acid. World Journal of Applied Chemistry. Vol. 4, No. 4, 2019, pp. 63-68. doi: 10.11648/j.wjac.20190404.14 Received: August 29, 2019; Accepted: September 20, 2019; Published: October 28, 2019 Abstract: Natural dyes are derived from natural sources such as plants, animals and minerals. They are mostly non- substantive and can be applied on textiles materials by using mordants. Synthetic dyes are derived from organic or inorganic compound. They are cheaper, offer a vast range of new colour and impart better properties to textile materials. Synthetic dyes are widely used in industries amongst which textile processing industries are the major consumers. Acid dyes are soluble in water and it can be permanently fixed to the fibre with the addition of a weak acid and heat. A series of acid dyes were synthesized by diazotization of 1-amino-2-naphthol-4-sulphonic acid and coupled with various naphthalene derivatives such as 1-nitroso-2-naphthol, 2-nitroso-1-naphthol, 1-naphthol, 2-naphthol and N, N-dimethyl aniline. Visible absorption spectra of the dyes were examined in distilled water, ethanol and ethanol plus few drop of concentrated hydrochloric acid. The FT-IR analysis was determined to confirm the functional group present in the synthesized dye. The dye was applied on polyamide (Nylon) fabric and the colour parameters of dyed fabrics were examined to have good exhaustion between pH 3–4.5 and more intense. After the dyeing process, the fabric was subjected to washing and light fastness. The remarkable degree of levelness and brightness of the synthesized acid dye on the nylon fabric is of good penetration, excellent affinity and very good fastness properties. Keywords: Acid Dyes, FT-IR, UV Visible, Percentage Exhaustion, Fastness Properties 1. Introduction Colourant is a term used for dyes and pigments [1]. A dye is a water-soluble substance from organic origin that when applied to a substrate provide colour by a process that alters any crystal structure of the coloured substances temporarily [2, 3] while a pigment is a coloured compound which is insoluble and from inorganic in origin [4]. But not all coloured compounds are textile dyes: some are only useful as indicators e.g. methyl orange, while some are used as stains or solvent dyes for colouring solvents such as petrol [5]. Dyes may be classified by their method of application to the substrate. They include acid dyes, direct dyes, reactive dyes, vat dyes, disperse dyes, azoic dyes, and several more types [6]. Natural dyes are mostly non-substantive and must be applied on textiles by the help of mordants, usually a metallic salt, having an affinity for both the colouring matter and the fibre [7]. Synthetic dyes are widely used in the textile, rubber product, paper, printing, colour photography, pharmaceuticals, cosmetics and many other industries, in which textile processing industries are the major consumers. Azo dyes represent the major and most versatile category of synthetic dyes [8-10]. A dye that contains sodium salts of a sulphonic acid group together with a phenolic group, are called acid azo dyes [11]. An acid dye is a dye that is typically applied to a textile at low pH. These dyes can be applied to nylon, wool or silk not cotton fabrics in the pH range 3.0–7.0. The wet-fastness of these dyes varies from moderate to good and their light fastness is generally in the blue-scale range 5.0–6.0 reported according to [12, 13]. Acid dyes are grouped based on their affinity, dyeing properties and chemical constitution of the dyes. There are different types of acid dyes reported by the researchers such as anthraquinone dyes, nitro dyes, triphenylmethane dyes and azo dyes [14-20]. Dyeing is the coloration of a textile material to a single solid shade. Dyeing is usually carried out in a dyebath containing water, dye and other chemicals (assistants) which assist dye absorption and retention on the