Justus von Liebig | Biography

Justus von Liebig did not make his reputation with a single discovery or innovation, but rather with tremendous versatility. He conducted research in organic and inorganic chemistry, agricultural chemistry, physiology and biochemistry, making significant contributions to the study of acids and bases, the chemistry of ether, the systematization of organic chemistry, and the production of industrial dyes as well as synthetic fertilizers. Liebig is considered to be one of the most important chemists of the nineteenth century.

Born in Darmstadt, Germany on May 12, 1803, Liebig was the son of a merchant who sold pharmaceuticals, dyes, and salts, so he developed a keen interest in chemistry early in his youth. By the time he was nineteen, he had earned his Ph.D. at Erlangen, and at the recommendation of Alexander von Humboldt was hired to work in the laboratory of Joseph Gay-Lussac, where he remained for two years. In 1825, he was appointed chairman of chemistry at the obscure University of Giessen, where he proceeded to build an excellent chemistry program. Considered a great teacher, he was among the first to focus on laboratory instruction as a means of educating chemists. He remained at Giessen for 27 years before he moved to the University of Munich, staying there until his death on April 18, 1873.

Liebig is probably best known to chemistry students as the inventor of the Liebig condenser, a distillation apparatus found in most every chemical laboratory but he also played a part in numerous key discoveries. For example, in the early 1820s Liebig and Friedrich Wöhler had been conducting individual research on inorganic chemicals, and Gay-Lussac noticed that a compound Liebig called silver fulminate had the same chemical formula as a compound Wöhler called silver cyanate, though the compounds were different chemically. Informed of this peculiarity by Gay-Lussac, Jöns Berzelius was inspired to derive the theory of isomers. Liebig and Wöhler began working together in organic chemistry, a field that lacked systematic theory at the time, and introduced a degree of methodical analysis to the field, including techniques to determine the content of various elements such as carbon, hydrogen, and halogens in organic chemicals. Upon discovering the benzoyl radical (C₆H₅CO-), they also attempted to find a way to define all organic chemicals as combinations of radicals (groups of molecules that tend to act as a unit). Though they failed, their efforts to present organizing principles in organic chemistry stimulated more successful attempts later.

Liebig made other noteworthy scientific contributions including data on fermentation and the calorific content of foods. His studies of plant biochemistry were particularly important to the future of agriculture, for he was among the first to theorize that plants obtain carbon not from organic compounds in the soil, but from atmospheric carbon dioxide. Libby also discovered that plants required simple mineral compounds from the soil to survive. This led him to develop the earliest artificial fertilizers.