By Annie Lu The year was 1856, on an Easter vacation from London’s Royal College of Chemistry. 18-year-old, aspiring chemist William Henry Perkin stumbled upon exactly what no one was expecting him to discover: mauve. When Perkin had first entered the Royal College in 1853, he was assistant to renowned scientist August Wilhelm Hofmann, who was attempting to synthesise quinine. Quinine, which is naturally derived from the bark of cinchona trees, is most commonly used as an antimalarial drug, but is also a mild antipyretic (reduces fever) and analgesic (relieves pain). Hofmann, and, by extension, Perkin, were trying to synthesize the antimalarial drug because at that time it was obtainable solely through cinchona bark, grown primarily on Southeast Asian plantations—understandably inconvenient for some. Failed attempt followed failed attempt, as chemistry was still primitive in this era. Perkin began a series of experiments in a rickety makeshift lab in his own home—and was unsuccessful yet again. Yet while examining the remnants of his experiment, Perkin noted that rinsing the leftover disaster solution with alcohol dissolved the remaining solid to yield a purple color. Further studies on that note (kept secret from Hofmann, since it was not relevant to his original work) eventually led Perkin to conclude he had synthetically produced a dye, which he called mauveine. We know today that mauveine, also referred to as aniline purple, is a mixture of four related aromatic compounds with different numbers and positions of methyl groups. In Perkin’s 1856 patent of the mauve-making process, this is what he describes: “I take a cold solution of sulphate of aniline.” Aniline sulfate is a toxic, white powder used to detect mechanical pulp paper. Cotton, linen, and hemp fibers turn aniline sulfate solution brown, for example. “And [I take] as much of a cold solution of a soluble bichromate as contains base enough to convert the sulphuric acid… into a neutral sulphate.” Perkins then details mixing, resting, filtering, and washing with water the solution, at that moment composed of a black powder and neutral sulphate. “I then dry the substance thus obtained at a temperature of 100 degrees centigrade, or 212 degrees Fahrenheit and digest it repeatedly with coal-tar naphtha until it is free from a brown substance which is extracted by the naphtha.” Coal-tar naphtha is obtained by distilling coal tar, which is where Perkin and Hofmann’s original attempts at synthesizing quinine come in. “I then free the residue from the naphtha by evaporation and digest it with methylated spirit… which dissolves out the new colouring matter.” During the time of Perkin’s discovery, all previous cloth dyes had to be naturally distilled, were expensive, and unfortunately unstable—the temporarily-vibrant color was easily faded by sun or washing. Purple was especially difficult and costly to produce, made from the mucus of certain mollusks. The year was 1856, at the height of the Industrial Revolution in the very cradle, the heart of it: England. Not only was the necessary resource for Perkin’s synthesis—coal tar—being produced in abundance as waste from factories, but the booming textile industry also presented a market for Perkin’s dye. Perkin was faced with the new endeavor of creating both supply and demand for his product: from being a precocious child scientist, Perkin partnered with his brothers to build a factory and publicized his creation. Publicity got a fortuitous jumpstart when Empress Eugénie, Napoleon III’s consort, and then-Queen of Britain Victoria adopted mauve for their royal wear. Perkin discovered not only an extravagant and attractive color, but fomented the chemical industry of synthetic dyes (which he patented) and also the pharmaceutical industry. He bettered the world of organic chemistry as a whole by stimulating the search for better understanding molecular structures. Following the initial stumble upon mauve, synthetic dye industries in the next fifty years produced other aniline dyes such as fuchsine, safranine, and induline—all made from coal tar. In 1906, the Society of Chemical Industry created the Perkin Medal to commemorate the discovery of mauve and awarded the medal to Perkin. Through a serendipitous accident, the fortune of good timing, and excellent personal character, Perkin ensured that his name would go down in chemical history. Citations“Quinine.” PubChem | Open Chemistry Database. NIH. https://pubchem.ncbi.nlm.nih.gov/compound/Quinine#section=Computed-Properties. “RSC: Mauveine - The Discovery and Inventor.” RSC - Advancing the Chemical Sciences, www.rsc.org/Chemsoc/Activities/Perkin/2006/minisite_perkin_mauveine_non_flash.html. “William Henry Perkin.” Chemical Heritage Foundation, 15 Sept. 2016, www.chemheritage.org/historical-profile/william-henry-perkin. Garfield, Simon. Mauve. London: Faber and Faber Limited. 2000. “Aniline Sulfate.” Aniline Sulfate - CAMEO, http://cameo.mfa.org/wiki/Aniline_sulfate. “Naphtha: chemical compound.” Encyclopedia Britannica. 20 Jul 1998, updated 11 Dec 2007. https://www.britannica.com/science/naphtha#ref284947. Suggested ReadingsAchan, Jane, et al. “Quinine, an Old Anti-Malarial Drug in a Modern World: Role in the Treatment of Malaria.” Malaria Journal, BioMed Central, 2011, www.ncbi.nlm.nih.gov/pmc/articles/PMC3121651/.
Nagendrappa, G. “Sir William Henry Perkin: The Man and his ‘Mauve’,” Resonance. Sept. 2010, http://www.ias.ac.in/article/fulltext/reso/015/09/0779-0793. Hennessey, Rachel. “Living in Color: The Potential Dangers of Artificial Dyes,” Forbes. 27 Aug. 2012, https://www.forbes.com/sites/rachelhennessey/2012/08/27/living-in-color-the-potential-dangers-of-artificial-dyes/#773cd7a2107a.
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