To the Editor:—
In late 1831, Guthrie, Soubeiran, and Liebig independently reported their discovery of a compound obtained by distilling a mixture of concentrated ethyl alcohol and chloride of lime (CaCOCl2). 1–3In 1834, Dumas elicited the product’s chemical formula (CHCl3) and named it chloroform. 1–3Soubeiran and Liebig realized that they had discovered a new compound, but Guthrie thought he had found a simpler and cheaper method of producing chloric ether. 4He learned of chloric ether and its potential medical use as a stimulant in the 1831 edition of Silliman’s Elements of Chemistry 5and was interested in the product’s commercial exploitation. 4
Although the fall of 1831 is commonly accepted as the date of its discovery, 1–3chloroform seems to have been produced at least 1 yr earlier, in mid-1830, by the German Moldenhawer. 6,7Moldenhawer, a pharmacist in Frankfurt/Oder, published in the early fall of 1830 a new process for removing the contaminant fusel oil from ethyl alcohol prepared from potatoes. 7In reviewing the various methods used to purify alcohol, Moldenhawer mentioned Zeise’s procedure 8of adding one-fourth loth (2.5 g) of chloride of lime to one quart (1 l) of ethyl alcohol, shaking the mixture frequently and vigorously for 20–24 h, and distilling out the alcohol (loth and quart were German measures of that period.) Moldenhawer judged Zeise’s method to be inadequate; he had found fusel oil in the distillate and none in the residue. He had also noticed that the vigorous shaking of the mixture released the strong odor of what he thought to be chloric ether (chloräther in German). Moldenhawer thus seems to have produced chloroform. Like Guthrie, he mistook the substance for chloric ether because of a similar smell.
In 1794, a group of Dutch chemists, 9mixing equal volumes of ethylene (C2H4) and chlorine (C12), obtained an ethereal liquid initially called oil of the Dutch chemists (1,2-dichloroethane). In 1816, Robiquet and Colin 10analyzed the composition and properties of the Dutch liquid, named it hydrochloric ether, and suggested its use as a medicinal stimulant. Thomson, professor of chemistry at the University of Glasgow, described the compound in the 1820 edition of his System of Chemistry 11and renamed it chloric ether. The name chloric ether was adopted by Silliman in the 1831 edition of his Elements of Chemistry. 5
Chloräther (1,2-dichloroethane) was well known in the German chemical literature at the time of Moldenhawer’s publication. 12,13His article 7shows an extensive knowledge of the contemporary chemical literature. He also must have experimented with chloric ether because he thought that he had noticed its smell in the mixture of alcohol and chloride of lime he had tested. Had he investigated the compound whose odor he had detected, or at least reported his discovery more extensively, he may have been the first discoverer of chloroform. Zeise, who mixed alcohol and chloride of lime even before Moldenhawer, may also have fortuitously produced chloroform, but the details and the date of his experiments remain unknown.
The authors thank Prof. Dr. H. W. Rösky (Göttingen); the librarians, J. Linder and S. Renner (Heidelberg); L. Künstling (Hannover); and S. Schmidt, Rohland (Leipzig) for their kind and generous help with the old German references.