Synthetic colorants indigo dyes

Use Intermediates, dyes (sulfur colors, indigo, methyl indigo), vulcanization accelerator, synthetic organic pharmaceuticals, flotation agent, acid inhibitor. 

As early as 2500 bce m India indigo was used to dye cloth a deep blue The early Phoenicians discovered that a purple dye of great value Tyrian purple could be extracted from a Mediterranean sea snail The beauty of the color and its scarcity made purple the color of royalty The availability of dyestuffs underwent an abrupt change m 1856 when William Henry Perkin an 18 year old student accidentally discovered a simple way to prepare a deep purple dye which he called mauveme from extracts of coal tar This led to a search for other synthetic dyes and forged a permanent link between industry and chemical research... 

Piesendy, all ceitified colois aie factory-piepaied materials belonging to one of several different chemical classes. Although a few such as D C Blue No. 6 (indigo) are known to exist in nature, certified colors owe their commercial importance to their synthetic production. Because of the starting materials used in their manufacture in the past, certified colors were once known as coal-tar dyes. Today, since most of the raw materials used in their preparation are obtained from petroleum, this term no longer appHes. 

Humans have used dyes to create color since the dawn of history. Until the mid-nineteenth century, all dyes were of natural origin. Many came from plants, such as indigo, a dark blue dye that was extracted from the leaves of a native East Indian plant. In 1856, the young English chemist William Perkin stumbled upon the first synthetic dye. Perkin was trying to synthesize quinine, a valuable antimalaria dmg. None of his experiments met with success. As he was about to discard the residue from yet another failed reaction, Perkin noticed that it was colored with a purple tinge. He washed the residue with hot alcohol and obtained a purple solution from which strikingly beautiful purple crystals precipitated. Perkin had no idea what the substance was or what reactions had created it, but he immediately saw its potential as a new dye. 

N.p. were used in antiquity as dyes. Among the oldest of these arc alizarin, indigo, tyrian purple, sa-ffan, keimes, crxdiineal and many flavonoid-contain-ing colored woods. In the dyeing industry they have now been largely replaced by superior synthetic com-potmds, but natural coloring materials are still used in the food industry. 

Synthetic dyes, such as indigo with different concentrations (20%-8o%), alizarin for red, auramine for yellow, naphthol for red and yellow, and aniline for blue or black color, have replaced the traditional natural dyestuffs [1, 2, 4, 6]. Examples of the synthetic dyes used in batik processing are Brenta Soga produced by ICI, Naphthol as produced by Bayer, and Anthrasol produced by Hoechst [4]. 

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