- Person
- Otto Wallach
- Lived
- 1847–1931
- Field
- Organic chemistry
- From
- German
The story
Essential oils, the fragrant liquids distilled from plants such as pine, lemon, peppermint and lavender, have been used for perfumes, flavourings and medicines since ancient times. In the nineteenth century chemists found that they contain families of closely related compounds called terpenes. Nearly a hundred had been described, usually named after the plant they came from, but many had the same formula and almost the same boiling point, and they changed into one another at the slightest provocation. Studying them seemed practically hopeless.
Otto Wallach, a German chemist born in Königsberg in 1847, whose father came from a Jewish family that had converted to Lutheranism, took up the problem at the University of Bonn after August Kekulé showed him an old cupboard full of bottles of essential oils. From 1884 he turned the hard-to-identify liquid terpenes into solid crystalline compounds, using simple reagents such as hydrogen chloride and hydrogen bromide, so that they could be compared and recognized even in mixtures. He showed that many of the supposedly different terpenes were identical, reducing the confusing list to a handful of real compounds, and he worked out how they rearrange into one another. He coined the names terpene and pinene and summed up his work in a 600-page book, Terpene und Campher, in 1909.
The work transformed the industry that processes essential oils. Manufacturers could now check the purity of their raw materials, which had often been adulterated, and develop new ways to make and use these compounds. At the 1910 Nobel ceremony the Swedish Academy reported that annual production of such preparations in Germany alone had risen from 12 million marks in 1885 to 45 to 50 million marks. It added that Wallach had never patented his discoveries but had always put his observations at the disposal of industry free of charge, and that many of his students carried his methods into industrial laboratories.
Terpenes and their relatives are among the largest families of natural molecules, from menthol and limonene to vitamin A and plant-derived medicines such as artemisinin. The modern fragrance and flavour industry rests on being able to identify and purify them, the skills Wallach first worked out and chose to share.
Why it matters
Wallach’s freely shared terpene chemistry underpins the fragrance and flavour industry and the study of many plant-derived medicines.
About Otto Wallach
German chemist who untangled the terpenes, the fragrant molecules of essential oils, laying the science under modern perfume and flavour chemistry. He never patented it. Nobel Prize 1910.
Sources
- Award ceremony speech, Nobel Prize in Chemistry 1910 NobelPrize.org
- Otto Wallach, Biographical NobelPrize.org
- Otto Wallach Wikipedia
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