Synthesis and Characterization of Mono-azo Dyes:A Combinational Study

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 Dyes are colourful compounds used to change the appearance of objects. Dyes belong to important group of compounds used to impart the desired colors. Dyes & dye intermediates are used as indicators also it is used in colouring foods, drugs, cosmetics, textiles, plastics, solvents, papers, etc. Among many different classes of dyes, azo dyes are certainly most important largest family of dyes. They contain azo group i.e., N=N linkage to two aromatic rings.

                        In this research work, we worked on the efficient & facile method which has been developed for the synthesis of Mono azo dyes. The nitro substituted aniline was synthesized by the reaction of substituted aniline with various coupling compounds. Product was purified by washing & recrystallization. The melting point & yield of product was recorded. During the research work we used nitro Substituted aniline because, as we know that benzene is colorless but instead of benzene, nitrobenzene has a pale-yellow color. So, here nitro group is responsible for color of nitrobenzene. That's why we use nitro substituted aniline. Correlation between structure and color of dye, effect of pH on dye was studied to verify Witt's Theory of color & constitution. We have summarized some recent synthesis of azo dye & the mechanism of azo dye. We can be applying these dyes to various type of fabrics to impart their beautiful color also we can use it in textile, fiber, printing industries, etc.