(b. Klein-Eichstedt, near Querfurt, Germany, 24 June 1835; d. Leipzig, Germany, 5 December 1902)
Wislicenus was a student at the University of Halle in 1853 when his father, a Lutheran pastor of liberal religious and political views, was ordered arrested for the publication of a biblical study. The family fled to the United States, where Wislicenus became an assistant in the analytical laboratory at Harvard. When the family returned to Europe in 1856, he completed his studies at Halle. Subsequently he was professor of chemistry at the Zurich Oberen Industrieschule (1861), associate (1864) and full professor (1870) at the Eidgenössische Technische Hochschule in Zurich. He succeeded Adolf Strecker at Würzburg in 1872 and Kolbe at Leipzig in 1885.
Wislicenus’ first papers were joint publications with Wilhelm Heintz, professor of chemistry at Halle. They studied the condensation of aldehydes with ammonia and isolated the base oxytetraldin in 1858. At Zurich he and his colleague Adolf Fick investigated the origin of muscle energy. According to Liebig, proteins produced force and their oxidation furnished the energy for muscle power. Carbohydrates and fats produced only heat. In 1865 Wislicenus and Fick tested this theory by climbing the Faulhorn in the Swiss Alps, calculating the work done during the ascent and measuring the amount of nitrogen in the urine excreted. They proved that the oxidation of protein contributed little to muscle energy and concluded that protein was used mainly in the growth and maintenance of tissues, carbohydrate and fat oxidation being the source of muscle energy.
Between 1863 and 1873 Wislicenus studied lactic and paralactic acids. These two acids and a third, hydracrylic acid, were monobasic acids with the formula C3H6O3. Wislicenus observed that lactic acid was optically active but paralactic acid was not. In 1863 he represented them according to the type theory, their radicalso being in a different order:
When structural formulas came into use during the 1860’s, he proposed that the two acids had identical structures. By 1873 Wislicenus established that lactic acid and paralactic acid were both α-hydroxypropionic acid, while hydracrylic acid was β-hydroxypropionic acid. He was the first to establish the structural identity of two different substances, and argued that ordinary structural formulas were inadequate: the two acids must be represented by three-dimensional formulas that indicate the different arrangement of the atoms in space. Wislicenus called this type of isomerism “geometrical isomerism.”
In 1874 van’t Hoff presented his theory of the tetrahedral carbon atom and asserted that it occurred to him after reading Wislicenus’ paper of the previous year. Wislicenus enthusiastically accepted van’t Hoff’s theory and wrote to him in 1875 for permission to have La chimie dans l’espace translated into German. He later contributed an introduction to the German edition.
Wislicenus was the leader in applying and extending the ideas of van’t Hoff and Le Bel, and his successes helped to bring chemists to the new field of stereochemistry. There was, however, no serious attempt to apply the theory of the tetrahedral carbon atom to cases other than optical isomers. Van’t Hoff had suggested that doubly linked carbon atoms could be represented by two tetrahedrons with one edge in common and that possibilities for isomerism occurred when two or more of the radicals attached to these carbon atoms differed.
In 1887 Wislicenus published an important paper on the stereoisomerism of unsaturated carbon compounds, extending the hypothesis along the lines suggested by van’t Hoff and also considering the attractive-repulsive forces of the atoms in order to determine the most probable geometric configuration of the atoms in the molecule. He showed how the interpretation of maleic and fumaric acids as geometric isomers explained their chemicaltransformations. In addition he determined the configurations of many unsaturated isomeric carbon compounds and investigated geometric isomerism in cyclic compounds.
Wislicenus contributed to several areas of organic chemistry. He introduced molecular silver as a synthetic agent, preparing adipic acid from β-iodo-propionic acid in 1869. Other syntheses include hydantoin (1873), glutaric acid (1878), vinyl ether (1878), cyclic ketones (1893), and vinyl acetic acid (1899). In a long series of researches on acetoacetic ester and its derivatives, he established the conditions for their hydrolysis, showing that acid hydrolysis produced a ketone, alcohol, and carbon dioxide, and alkaline hydrolysis a fatty acid and alcohol (1878). Wislicenus elucidated the structure of acetoacetic ester by replacing hydrogen with sodium. The ethyl sodioacetoacetate combined with an alkyl iodide gave high yields of a substituted acetoacetic ester that could accept another sodium atom and exchange it for a second alkyl group.
I. Original Works. Wislicenus’ study of the geometric isomerism of unsaturated compounds is “Über die räumliche Anordnung der Atome in organischen Molekülen und ihre Bestimmung in Geometrischisomeren ungesättigten Verbindung,” in Abhandlungen der K. Sächsischen Gesellschaft der Wissenschaften, math.-phys. Kl., 14 (1887, 1–78, translated by George M. Richardson in Foundations of Stereochemistry: Memoirs by Pasteur, Van’t Hoff, Le Bel and Wislicenus (New York, 1901), 65–132. Wislilcenus rewrote Strecker’s textbook, originally based on an earlier work of Regnault, Regnault-Strecker’s Kurzes Lehrbuch der Chemie, 2 vols. (Brunswick, 1874–1881); there is an English version of the organic chemistry part: A. Strecker’s Short Textbook of Organic Chemistry by Dr. J. Wislicenus, translated and edited by W. R. Hodgkinson and A. J. Greenaway (London, 1881).
Significant papers include “Über ein basisches Zerset-Zungsproduck des Aldehydammoniaks,” in Annalen der Physik und chemie,105 (1858), 577–597, written with W. Heintz; “Studien zur Geschichte der Milchasäure und ihrer Homologen,” in Justus Liebigs Annalen der Chemie,125 (1863), 41–70; 133 (1865), 257–287; and 146 (1868), 145–161; “On the Origin of Muscular Power,” in Philosophical Magazine, 4th ser., 31 (1866), 485–503, written with A. Fick; “Synthetische Untersuchungen über die Säuren der Reihe,” in Annalen der Chemie,149 (1869), 215–224; “Über die isomeren Milchsäuren,” ibid.,166 (1873), 3–64; “Über die optisch-active Milchsäuren der Fleischflüssigkeit, die Paramilchsäure,” ibid.,167 (1873), 302–346; “Über Acetessigestersynthesen,” ibid.,186 (1877), 161–228; “Spaltung des Acetessigester und seiner Alkylsubnstitutionosproducte durch Basen,” ibid.,190 (1878), 257–281; “Über Vinyläthyläther,” ibid.,192 (1878), 106–128; “Untersuchungen zure Bestimmung der räunmliche Atomlagerung,” ibid.,246 (1888), 53–96, 248 (1888), 281–355, and 250 (1889), 224–254; and “Über Ringketonoe,” ibid.,275 (1893). 309–382.
II. Secondary Literature. There are two detailed accounts of Wislicenus’ work: Ernst Beckmann, “Johannes Wislicenus,” in Berichte der Deutschen Chemischen Gesellschaft,37 (1904), 4861–4946, which includes a bibliography; and Willliam Henry Perkin, Jr., “The Wislicenus Memorial Lecture,” in Memorial Lectures Delivered Before the Chemical Society, II (London, 1914), 59–92, which originally appeared in Journal of the Chemical Society,87 (1905), 501–534.
Albert B. Costa