A Failed Malaria Cure Gave Us Mauve, the First Synthetic Dye

In 1856, a young chemist named William Henry Perkin set out to make a malaria cure and instead invented a color. The narration frames this as more than a lucky break, because the discovery opened a new branch of science.

The host argues that thanks to this dye, an entirely new field of study opened up, one that made chemicals with no obvious link to color, including perfumes, pesticides, and drugs.

In the 19th century, malaria killed thousands of people a year even in Europe. The best treatment was quinine, a compound from the bark of the cinchona tree native to South America.

Spain kept tight control over quinine's distribution because it was so valuable, and Britain eventually smuggled cinchona seeds to grow its own trees. Some chemists then wondered whether they could make the molecule themselves.

Perkin first got into chemistry around age 13 and studied it at college in 1853. He then worked under August Wilhelm von Hofmann at the Royal College of Chemistry in London, where Hofmann suggested he try making quinine.

The task was hard. Chemists knew only quinine's atomic makeup of 20 carbon, 24 hydrogen, two nitrogen and two oxygen atoms, not how they were arranged. Perkin planned to start from coal tar, a cheap, unpleasant byproduct of coal gas production, using allyltoluidine, a coal tar compound with about half the atoms of quinine, and to join two of its molecules together.

Perkin's first experiment did not produce quinine. He then switched to a simpler coal tar ingredient, aniline, and that also failed, leaving a black, gunky product.

Most chemists would have thrown the residue out, but Perkin kept investigating. He found that mixing the residue with methanol and separating it out produced a purple dye.

Before Perkin, natural dyes had been used for ages, yet some were toxic, some washed out easily, and there were not enough of them to cover the full range of colors people wanted. Synthetic dyes were a new technology at the time.

Earlier synthetic attempts existed, such as picric acid, but it worked better as an explosive than as a dye.

Unlike picric acid, Perkin's purple dye adhered well to silk, resisted fading in sunlight, and was not explosive.

Perkin initially named the dye after the compound used to make it, "aniline purple," or after a natural sea-snail dye, "Tyrian purple."

The name is ironic because the aniline he used was contaminated with toluidine, which proved more reactive and helped produce a better color than pure aniline alone.

The dye was called mauveine. Perkin received a British patent in 1857, but his French patent application fell through because of a paperwork error.

Without patent protection in France, French dyers made the dye freely and named it mauvéine after the wild mallow flower, since mauve means mallow in French.

Perkin left school and, together with his brother, set up a manufacturing plant, a gamble made despite his lack of experience in textiles or business, and a loan from his father that he needed to get the plant running. He had no textile or business experience and needed a sizable loan from his father.

Yields were poor: one gram of mauveine required processing about 690 grams of coal tar. Dyers also had not yet worked out how to apply the new dye to fabric.

For a time mauve was all the rage. Empress Eugénie of France loved the color, and Queen Victoria wore a mauve dress to her daughter's wedding. Mauveine was even used to dye postage stamps until the 1880s.

Mauve later fell out of style, and chemists had produced many other bright colors. Perkin sold the factory in 1873 to retire and focus on chemistry research.

Synthetic dye production spread quickly, especially in Germany, where Bayer started as a dye business. As the field grew, coal tar proved to be a source of more than dyes.

Perkin developed coumarin, one of the first synthetic perfumes. In 1879, Constantin Fahlberg developed saccharin, about 550 times sweeter than sugar, also by accident.

Hermann Kolbe made synthetic salicylic acid from coal tar in 1874, but it upset patients' stomachs. In 1897, Bayer's Felix Hoffman created acetylsalicylic acid, which the company sold as Aspirin.

Researchers tested variants of molecules that had some useful effect, which sometimes led to surprising breakthroughs. Painkillers, vitamins, synthetic hormones and anesthetics all came out of this work.

Some molecules worked as both dyes and medicines. Methylene blue turns fabric blue, stains malaria parasites in tissue samples, and can kill the parasite that causes malaria.

It took almost 90 years before Harvard chemists worked out a route to quinine. They actually made a related chemical, d-quinotoxine, and pointed to an earlier paper that claimed it could be converted into quinine, a claim they did not confirm.

A complete synthesis was published by a different route in 2001, and the original procedure was not verified until 2008. Chemists are still finding new ways to make quinine today.