In the Thick of Organic Matter

Abstract

Between summer 1806 and spring 1808 the French chemist Louis Jacques Thenard (1777–1857) performed a series of experiments with ethers. At the time, ethers had already a history. The properties of pure ether, prepared from spirit of wine and sulfuric acid, were first described in an article by the German chemist August S. Frobenius, published in the Philosophical Transactions in 1730. As Frobenius had commercial interests, he kept the method of preparation secret. Together with his English colleague Godfrey Hanckwitz he wanted to sell pure ether as a novel, most effective remedy. But immediately after Frobenius’ publication several British, French and German chemists and apothecaries set out to reproduce pure ether, and in 1741 Cromwell Mortimer made the production process public. Twenty years later, chemists and apothecaries had tested further possibilities of producing ether from spirit of wine and acids other than sulfuric acid, such as nitric acid, muriatic acid (today hydrochloric acid), and acetic acid. Hence the article “ether,” published in Pierre Joseph Macquer’s famous dictionnaire de chimie, mentioned different ethers, such as “ordinary” or “vitriolic ether,” “nitric ether,” “acetic ether” and so on (Macquer 1766, 1:455–470). By the end of the eighteenth century the two chemical teachers of Thenard, Antoine-Francois Fourcroy and Louis N. Vauquelin, undertook collaborative efforts to explain the formation of ordinary ether. Since the operation yielded many byproducts of ether, and since sulfurous acid was one of the byproducts, many chemists believed that ordinary ether resulted from the oxidation of alcohol (contained in spirit of wine) by sulfuric acid; according to this understanding the sulfurous acid was the reduction product of sulfuric acid. This explanation was congruent with chemists’ more general views about the action of strong mineral acids on organic substances. For example, in his chemical textbook Fourcroy pointed out that strong acids “engender a profound alteration of plant materials. When they are power-