Liebermann, Carl Theodore

(b. Berlin, Germany, 23 February 1842; (d. Berlin, 28 December 1914)

chemistry.

Liebermann was the son of Benjamin Liebermann, a cotton manufacturer. As a child he attended a private boys’ school and then the Gray Cloister Gymnasium, from which he graduated in 1859. His father wanted him to work in his factory and eventually assume its direction, but Liebermann preferred to continue his studies at the university. Since he chose to study chemistry—which might have been useful in the cotton industry—his father encouraged him. In 1861 he went to Heidelberg to study spectral analysis with Bunsen. The following year he returned to Berlin. Although laboratory space was scarce, he found a place with F. Sonnenschein. In 1863 he moved to Baeyer’s laboratory and two years later completed a paper on propargyl ether.

Liebermann then joined the firm of Koechlin, Batungarten and Co. as a chemist. Here he learned about the dye industry while also discovering that his real interest lay in pure rather than applied science. After spending several months in the family factory to satisfy his father, he returned to Baeyer’s laboratory in 1867. After Graebe’s departure from the laboratory, Liebermann became Baeyer’s assistant. He soon formed a close personal relationship with Baeyer and qualified himself to teach at the technical school in Berlin. In 1870 he also became a privatdocent at the University of Berlin. When Baeyer left Berlin in 1873, Liebermann became professor ordinarius at the Gewerbeakademie. He remained at the academy, which later became the Charlottenburg Technical High School, for the rest of his career. During this time he directed the research of dozens of students.

In 1868 Liebermann became a member of the Deutsche Chemische Gesellschaft. After 1870 he continually held a position of leadership in the society and was president twice. He helped to found the Hofmann Haus and to promote an association of laboratory students. He was a member of the scientific academies of Uppsala, Christiania, and Gottingen, the Manchester Literary and Philosophical Society, and the Chemical Society of London. In 1906 he received the Perkin Medal. He married Tony Reichenheim in 1869 and they had one daughter, Else.

Liebermann produced more than 350 scientific papers and directed the work of many students. Most of his work was in the area of aromatic organic chemistry. He became interested in this area as a student when lie synthesized alizarin with Graebe. They used Baeyer’s zinc dust method to show that alizarin is derived from anthracene; they also showed that purpurin, a second colored substance of madder, was trihydroxyanthraquinone,

With this introduction to anthracene compounds, Liebermann prepared halogen derivatives and investigated the hydrogen addition products. He studied the monocarbonic acids of anthracene and prepared phenol derivatives. As early as 1868 Graebe and Liebermann had suggested that anthracene was a ring structure. Heinrich Limpricht’s synthesis made both

possible formulas; Liebermann felt through his work on the placement of oxygen in alizarin that the latter formula was the most probable. Liebermann’s formula proved to be correct when W. A. van Dorp in 1872 produced anthracene from benzyl toluol in Liebermann’s laboratory. While studying the hydroxyl isomers of anthraquinones, Liebermann found a way of exchanging the hydroxyl with an amide and eliminating the latter through a diazo reaction.

Liebermann then turned to the methyl homologs of anthraquinones: he investigated chrysophanic acid found in rhubarb and showed it to be methyldi-hydroxyanthraquinone. He proposed that the hydroxy-anthraquinones were part of a reduction series of anthracene. Between 1876 and 1881 he was able to produce most of the compounds for which he had proposed structural formulas. In his work on reduction series of anthracene. Liebermann also became interested in oxyanthraquinones. One of these compounds, Goa powder or chrysarobin, was of pharmacological interest. Later researchers extended his work on the relationship between hydroxyl placement and therapeutic effectiveness.

Liebermann also undertook an extensive study of naphthalene compounds. He wanted to understand the basis for the location of substitution derivatives of naphthalene and to produce a whole series of β-naphthalene derivatives. He was successful, for he produced β-naphthylanine from α-naphthylamine with Scheidung. He also found retune, chrysene, and epicene, and soon began to study other highly colored condensed aromatics

Liebermann also studied the dye cochineal, or carminic acid. Paul Schutzenberger and Warren de la Rue had both investigated this substance and each had assigned to it a different formula. Liebermann and van Dorp finally showed that it contains ruficoccin and ruficarmin, derivatives of anthracene and α-naphthaquinone. Other natural and artificial dyes on which Liebermann worked include β-rosanilinc, hematoxylin, and xanthorhamnin. He was interested in spectrographic work which might relate color production in plants to molecular constitution.

Liebermann and his students investigated the alkaloids of coca. They devised technical methods for the production of cocaine and related compounds and studied the isomeric cinnamic acids.

Since his work on alizarin in 1868, Liebermann had tried to relate the structure ot a compound with its color and its usefulness as a dye. Colors were generally produced by reduction. He felt that the color must therefore be due to unsaturated valences or an inner storage capacity in a molecule which exceeded the minimum force necessary to hold the molecule together. Compounds must have a specific composition to be mordants. In alizarin he found that the placement of the two hydroxyl groups influenced the color. Further study on the significance of the ortho position was done by Alfred Werner with organometallic compounds.

BIBLIOGRAPHY

I. Original Works. Works by Liebermann include “Ueber Alizarin und Anthracene,” in Berichte der Deut-schen chemischen Gesellschaft,1 (1868), 49-51, written with K. Graebe; “Ueber den Zusammenhang zwischen Molecularconstitution und Farbe bei organischen Verbindungen,” ibid,1 (1868), 106-108, written with Graebe; “Ueber kunstliche Bildung von Alizarin,”ibid.,2 (1869), 332-334, written with Graebe; “Ueber die isomeren α-und β-Derivate des aphtalins,”ibid.,6 (1873), 945-951, written with A. Littler; “Zur Kenntniss des Co Chenille-farbestoffs” ibid.,4 (1871), 655-658, written with W. A. van Dorp; and “Reduktionsversuche am Anthrachinon,”ibid.,13 (1880), 1596-1603.

II. Secondary Literture. For information on Lie bermann’s life, see James Parting Ton, A History of Chemistry, IV (New York, 1961), 790; and O. Wall Ach and P. Jacobsen, “C. Liebermann,” in Berichte der Deutschen chemischen Gesellschaft, 51 , pt, 2 (1918), 1135-1204.

Ruth Gienapp Rinard