One hundred and fifty years ago this week, a teenager experimenting in his makeshift home laboratory made a discovery that in effect launched the modern chemicals industry. William Perkin was an 18-year-old student of August Wilhelm Hofmann at the Royal College of Chemistry in London, working on the chemical synthesis of natural products. In a classic case of serendipity, Perkin chanced on his famous ‘aniline mauve’ dye while attempting to synthesize something else entirely: quinine, then the only known remedy for malaria.

As a student of the renowned German chemist Justus von Liebig, Hofmann had made a name for himself by showing that a basic compound called aniline, obtained from coal tar, had the same properties as a compound distilled from raw, plant-derived indigo. Coal tar was the residue of coal-gas production, and there was intense interest in finding uses for the aromatic compounds, such as aniline, that could be extracted from it.

Working at home, Perkin tried to use an aniline derivative to make quinine by oxidation, based on the similarity of their chemical formulae (their molecular structures are very different). The reaction produced only a reddish sludge. But when the inquisitive Perkin tried the reaction using aniline instead, he got a black precipitate that dissolved in methylated spirits to give a purple solution. Textiles and dyeing being big business at the time, Perkin was astute enough to test the coloured compound on silk, which it dyed richly. Hitherto, almost all dyes were natural compounds extracted from plants and animals.

Credit: SCIENCE MUSEUM

Boldly, Perkin persuaded his father and brother to set up a small factory with him to manufacture the dye, which he called mauve; the picture here is of a shawl, dyed with mauve, from 1862. The Perkins and others (including Hofmann) soon discovered a whole rainbow of aniline dyes, and by the mid-1860s aniline-dye companies included the nascent giants of today's chemicals industry, such as Bayer, Hoechst and BASF.