Dyes

The use of dyes dates back thousands of years, and still continues to this day, perhaps more than ever.  Though they may seem insignificant in shaping human histroy, they have in fact caused indirect developments in other fields.  For example, the dye indigo, from the Indigofera tinctoria plant, was first synthetically produced and marketed by the German chemical company Badische Anilin und Soda Fabrik (BASF).  This gave it the financial capital and chemical knowledge to expand into a variety of other fields and become one of the five largest chemical companies in the world.  The indigo molecule is blue, but is the product of two colorless oxidized indican molecules.  Most dyes follow this pattern, being altered from their colorless parent molecule to form colored compounds, such as alizarin (Turkey red) and its parent molecule anthraquinone.  The French army incorporated both indigo and alizarin into their military uniforms, as well as the uniforms they supplied to the United States during the American Revolution.

Another example is the colorless naphthoquinone which produces its derivatives of juglone (brown) found in walnuts, and lawsone (red-orange) found in Indian henna.  Naphthoquinone is also the parent molecule of echinochrome, carminic acid, and kermesic acid.  Echinochrome is a red pigment found in sand dollars and sea urchins.  Carminic acid, which makes up the scarlet cochineal dye once used by the Aztecs, contains numerous hydroxide groups, which is attributed to a brighter color.  The British army adopted cochineal-dyed uniforms in the 1700s, and became known thereafter as redcoats.  Kermesic acid was similar to carminic acid but was found in Egypt and never went into widespread use.

The primary yellow dye in use since ancient times and up until recently was saffron, from the Crocus sativus plant.  Similar to beta-carotene, found in carrots, saffron is a long carbon chain with alternating double bonds.  Another yellow dye used was picric acid (trinitrophenol), but was also highly explosive and was later used by the British in the early stages of the first World War.  Synthetic dyes, such as mauve which produced a brilliant lavender purple, soon replaced naural dyes, and promoted the growth of numerous chemical companies, especially those in Germany.  Though the affect of dyes on human history may not be so obvious as the affect other compounds had, they certainly made their mark, one way or another.