Dyes

Dyes

     It is believed that the extraction of dyes and dyestuffs may have been the first attempt at chemistry, occurring as early as 3000 B.C.. The dyes were typically extracted from plants, and the extraction processes were often complicated. Although they were highly desired, the early dyes had problems- they did not adhere to untreated fibers, they faded quickly, and they were hard to obtain. Blue was a very desired color, but it was very difficult to obtain because blue shades are not commonly found in plants. However, Indigofera tinctoria was a major source for indigo, the blue dye. The leaves of the indigo plant are not naturally blue, but after being fermented under alkaline conditions and oxidized, a blue color appears. Although blue was valuable, the most expensive dye was Tyrian purple, and it was often restricted to wear by the king or emperor only. This dye is a dibromo derivative of indigo- an indigo molecule with two bromine atoms- and is obtained from the mucus secreted by many species of marine mollusks. Greek mythology credits Hercules with the discovery of Tyrian purple when he noticed that his dog's mouth turned purple after eating shellfish. Tyrian purple was so desired, that by 400 A.D., the shellfish that produced it were almost extinct. Syntheitc indigo was not available until the end of the nineteenth century, when German chemist Johann Friedrich Wilhelm Adolf von Baeyer investigated the structure of indigo and found a way to make it from abundant materials. However, it wasn't until 17 years later that synthetic indigo, marketed by Badische Anilin un Soda Fabrik (BASF), was ready for commercial use.

     Dyes are organic compounds of color that absorb certain wavelengths of visible light. The molecule's absorption and reflection of certain wavelengths depends on the amount of conjugated bonds. Pigments are inorganic materials that are used for color, and they are completely unrelated to conjugated bonds. Synthetic dyes were created in the late 1700s, starting with picric acid- a molecule used in World War I munitions. It produced a strong yellow color, but it was difficult to obtain and potentially very explosive. By 1856, William Henry Perkin created an artificial dye at the age of 18. This dye was called mauve; it was a purple that remained colorfast and did not fade. BASF was established in 1861, and in 1868 Carl Graebe and Carl Liebermann created the first synthetic alizarinn. Hoechst was established a year after BASF and also synthesized alizarin. Bayer and Company, though most famously known for aspirin, was originally set up in 1861 to produce aniline dyes. After World War I, the economy and industry conditions in Germany plummeted, so the chemical companies formed a conglomeration known as IG Farben. During World War II, the company contributed to the Nazi Party and took control of chemical plants in countries occupied by Germany. After the war, IG Farben's growth was stopped, and the companies split into Bayer, Hoechst, and BASF again.