Molecule of the Day

The word chromatography, reveals its origins – in the beginning of the 20th century, Mikhail Tsvet – color compounds. The modern stable of robust, tunable separation techniques (i.e., chromatography) is probably one of the most important things chemistry has given us – and it’s only a hundred years old. Today, chromatography is used mostly to separate compounds without any visible color at all!

It’s hard, however, to understate the importance of dyes in the development of modern chemistry. We take colored fabrics completely for granted today, but dyes used to be a luxury. Dyes, too, also drove the development of modern pharmaceuticals (this isn’t extremely surprising – most drugs and dyes are aromatic small molecules of some kind). Some papers (often older ones) belie the colorful origin of many modern pharmaceuticals by referring to their studied prototype drug as a “dye.”

One seminal synthetic dye – in fact, the first reproduction of a natural one – is alizarin.

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Alizarin is a pigment found in the madder root, which was used as a dye throughout essentially all of history. From King Tut, to Charlemagne, to the vikings, the madder root was used as a dyestuff until the 1860′s. Then, a synthetic route was discovered, starting from anthracene – dirt cheap stuff you can get from coal tar. Even with 19th century techniques and supply stocks, the new pigment was half as expensive as the natural stuff, and the market for a plant that had been cultivated for millenia promptly collapsed.

These new-fangled chemists were on to something.

Comments

  1. #1 Uncle Al
    April 28, 2007

    British redcoats were clothed by the indefatigable jaws of French peasant women. Alizarin is a glycoside in madder root. Amylolytic enzymes in spit cleave it. Take your white cloth, dip in aqueous alum then carbonate to deposit aluminum hydroxide gel, then to the fast alizarin lake.

    The Middle East worked in kind. Macerate and leach seeds of Syrian rue. The aluminum lake in wool is the brilliant red color of “oriental” carpets. Now for the fun part! Alizarin is something of a fungicide and pediculoside (always useful for soldiers). The active chromophore in Syrian rue is harmine alkaloids – potent psychomimetics that elicit giant talking spirits rather than geometric color displays. The world’s three major religions – all of them violent and hallucinatory – may have been bootstrapped by sweating asses snuggling red carpets.

  2. #2 Chemist
    May 1, 2007

    Since you are mentioning chromatography I would like to add that chromatography is not only the most important thing chemistry has given us, but it is considered as one of the most important discoveries in the history of science by IUPAC.

  3. #3 Alfred Russel Wallace
    May 2, 2007

    Robin Hill, he of photosynthesis fame, grew madder in his greenhouse in Cambridge, annointing it with colchicine in hopes of getting some tetraploid sports. My understanding is that although successful, these plants produced no extra alizarin.
    Achim Trebst made the lovely toast at a meeting in Robin’s Honor, in Bochum, along the lines of “And his friends will understand when I say that Robin grows madder – every year”