1.1 Introduction
Azo dyes are an important class of organic chemicals containing at least one azo chromophore (-N=N-) which donors the color for this famous type of dyes (Kılınçarslan et al., 2007). They play essential role in academic and applied research (Abbas et al., 2018). Electronic and geometrical features of azo metal dyes induce redox, nonlinear optical and magnetic properties and these properties lead to increase the sensitivity and stability of these compounds towards optical data storage device (Ferreira et al., 2017; Shafeeulla et al., 2017). Azo compounds are class of chemical compounds that are continuously receiving attention in scientific research (Diler et al., 2016).
As a prelude to other parts of this study, this chapter will discuss the background upon which this study was initiated, the statement of problems that led to this study, the Aim and Objectives of the study. Others are Significance of the study, Scope of work, Research questions, Limitations of the Study and Definition of technical terms.
1.2 Background of Study
Azo dyes consider significant analytical reagents for the micro-estimation of metal ions. 1- (2-Pyridylazo)-2-naphthol considers well-known azo dye with term PAN which forms stable complexes with many metal elements (Abbas et al., 2018). In the same time, it is sensitive for trace concentration of metal elements and trace elements (Wang et al., 2016; Shokoufi et al., 2007). Presently, thousands of synthetic dyes are obtainable in the market (Hanadi, et al., 2018). Azo dyes constitute one of the largest and most varied groups of synthetic organic dyes in use today. The history of dyeing could be divided into two great periods, the "pre-aniline," extending to 1856 and the "post- aniline" period (Xu, H. & Zeng, 2010). Among them organic chromophores including azo compounds are widely utilized as pigments in many commercial products. The dyes known as monoazo dyes have only one (-N = N -) group while diazo and triazo dyes contain two and three (-N = N -) group, respectively.
The azo groups are generally connected to benzene and naphthalene rings, but can also be attached to aromatic heterocycles or enolizable aliphatic groups (Hunger, 2000).Synthetic dye manufacturing started in 1856, when the English chemist W.H. Perkin, in an attempt to synthetize quinine, obtained instead a bluish substance with excellent dyeing properties that later became known as aniline purple, Tyrian purple or mauveine. Henry Perkins 18 years old patented his invention and set up a production line. This concept of research and development was soon to be followed by others and new dyes began to appear on the market, a process that was strongly stimulated by Kekules discovery of the molecular structure of benzene in 1865. In the beginning of the 20th century, synthetic dyestuffs had almost completely supplanted natural dyes (Welham, 2001).
The importance of azo-dyes is due to its economy, versatility, relative ease of production and good dying performance, and sequential anaerobic–aerobic treatment of azo dyes (decolourisation and amine degradability) (Patel et al., 2007). Synthetic dyes have been extensively used in numerous industrial processes and the target of dying process is color durability as well as resistance to physical and chemical degradation (Santhanalakshmi & Komalavalli, 2012). Furthermore, azo dyes have been investigated widely due to their excellent thermal and optical features with interesting applications in optical recording medium, toner, ink-jet printing, and oil-soluble light fast dyes (Arunkumar et al., 2005). They are usually strongly colored compounds which can be intensely yellow, red, orange, blue or even green, based on the exact structure of the molecule. As a result of their color, azo compounds have been tremendously important as dyes and also as pigments for a long time (Otutu JO Synthesis and application of azo dyes derived from 2-amino-1, 3, 4-thiadiazole-2-thiol on polyester fibre, 2013) In fact, about half of the dyes in industrial application today are azo dyes, which are mostly prepared from diazonium salts (Adegoke et al., 2008).
Azo dyes contain at least one nitrogen-nitrogen double bond (N=N), however many different structures are possible (Kirkan and Gup, 2008). Anti- microbial agents play a major role in maintaining good health (Ahamed & Lakshmi, 2018). Some azo dyes have been found to have antimicrobial properties due to the presence of active functional groups, this biological activity of some azo dyes has increased their usage in textile, foods, and pharmaceutical industries. They have this vital ability to inhibit microorganisms which cause degradation of textile materials, degradation of food materials, skin diseases produced from bacteria which live inside clothing and textile fabrics and other ailments that affect human health (Balcerzak et al., 2014).
Therefore, in Nigeria where the research was carried out, the activities that was conducted is to know the Synthesis of Azo Dye From 2, 4-Dinitroaniline, 3-Amino-5-Methylpyrazole and Byroscarpus Coccineus.
1.3 Statement of Problems
The major problems encountered in this research work include;
- Non availability and delay in the arrival time of the chemicals since they are imported.
- Difficulty in choosing a suitable solvent for the purification of dye sample produced, since the dye sample does not dissolve in some of the solvent readily available.
1.4 Aim and Objectives of Study
The aim of the study is to Synthesize the Azo Dye from 2, 4-Dinitroaniline, 3-Amino-5-Methylpyrazole and Byroscarpus Coccineus. In achieving this aim, the following specific objectives were laid out as follows:
- To determine the effect of time and temperature on Azo Dye exhaustion; and
- To examine the electronic spectra of azo dye ligand (L) and its synthesized complexes.
1.5 Research Questions
The study came up with research questions so as to be able to ascertain the above stated objectives. The specific research questions for the study are stated below as follows:
- What is the effect of time and temperature on Azo Dye exhaustion?
- What are the electronic spectra of azo dye ligand (L) and its synthesized complexes?
…
