Until the mid-19th century, all dyes were derived from the leaves, twigs, roots, berries, or flowers of various plants or from animal substances. Tyrian purple, used by the Phoenicians in the 15th century BC, was produced from certain varieties of crushed sea snails. The use of indigo as long ago as 3,000 BC has been documented; synthetic indigocis still an important dye because it is exceptionally fast.
The textile dyeing industry in Europe originated in the 16th century. when the Portuguese, Dutch, and English introduced indigo. Natural dyes such as Cochineal, Turmeic, Wood, Madder, and Henna remained the primary source of dye colors until the discovery of the first synthetic dye in 1856 by Sir William Henry Perkin.
Perkin, an English chemist, was working with the coal-tar derivative ANILINE when he accidentally discovered that a by product of aniline oxidation had dyeing capabilities. He established a factory to manufacture his new purple dye, mauve; other experiments began to produce new colors from aniline and other coal-tar derivatives. Alizarin was the first natural dye to be produced synthetically, (1868), and by 1880 indigo had been synthesized. By 1916, an extensive technology had developed, most of it concentrated within a German cartel that held a virtual monopoly over dye production. Only with the onset of World War II did Germany lose its position as the world’s principal supplier of dyes. Today, the U.S. dye industry, aided by the post-World War II acquisition of German technology, has become a major exporter of dyes.
By 1881 Perkin had synthesized glycocoll, cinnamic, courmarin, and several unsaturated acids. In 1878. this latter work resulted in the “Perkin synthesis,” the preparation of unsaturated acids by the condensation of an aromatic aldehyde with the salt of a fatty acid. The synthesis of coumarin was of special importance, being the first vegetable perfume ever produced from coal-tar, Perkin also undertook a comprehensive study of optical isomerism. From 1881 to the end of his life he devoted himself to a study of magnetic rotation, a tool to prove invaluable in determining organic structures.
Mordants are chemical substances formerly used to confer affinity for textile fibers to natural and early synthetic dyes. Alizarin, applied with an aluminum-salt mordant, was used extensively to produce bright red shades on cotton. Tannin and sodium stannate were used to form insoluble salts with basic dyes on silk. Chromium still is used to a limited extent in the United States, and to a greater extent abroad, with azo and basic dyes for the dyeing of wool and the printing of cotton. Chemically the quantity of a substance having the weight in grams numerically equal to its modular weight refers to mole. A mole of a substance contains 6.02257 x 10
molecules. Given this formula, the types of dyes can be clearly discussed in the following section.