Justus Von Liebig

Liebig left Erlangen in March 1822, in part because of his involvement with the radical Korps Rhenania (a nationalist student organization), but also because of his hopes for more advanced chemical studies. The circumstances are clouded by possible scandal. In late 1822, Liebig went to study in Paris on a grant obtained for him by Kastner from the Hessian government. He worked in the private laboratory of Joseph Louis Gay-Lussac, and was also befriended by Alexander von Humboldt and Georges Cuvier (1769–1832). Liebig's doctorate from Erlangen was conferred on 23 June 1823, a considerable time after he left, as a result of Kastner's intervention on his behalf. Kastner pleaded that the requirement of a dissertation be waived, and the degree granted in absentia.

Liebig left Paris to return to Darmstadt in April 1824. On 26 May 1824, at the age of 21 and with Humboldt's recommendation, Liebig became a professor extraordinarius at the University of Giessen. Liebig's appointment was part of an attempt to modernize the University of Giessen and attract more students. He received a small stipend, without laboratory funding or access to facilities.

His situation was complicated by the presence of existing faculty: Professor Wilhelm Zimmermann (1780–1825) taught general chemistry as part of the philosophy faculty, leaving medical chemistry and pharmacy to Professor Philipp Vogt in the medical faculty. Vogt was happy to support a reorganization in which pharmacy was taught by Liebig and became the responsibility of the faculty of arts, rather than the faculty of medicine. Zimmermann found himself competing unsuccessfully with Liebig for students and their lecture fees. He refused to allow Liebig to use existing space and equipment, and finally committed suicide on 19 July 1825. The deaths of Zimmermann and a Professor Blumhof who taught technology and mining opened the way for Liebig to apply for a full professorship. Liebig was appointed to the Ordentlicher chair in chemistry on 7 December 1825, receiving a considerably increased salary and a laboratory allowance.

From 1825 to 1835, the laboratory was housed in the guardroom of a disused barracks on the edge of town. The main laboratory space was about 38 m (410 sq ft) in size and included a small lecture room, a storage closet, and a main room with ovens and work tables. An open colonnade outside could be used for dangerous reactions. Liebig could work there with eight or nine students at a time. He lived in a cramped apartment on the floor above with his wife and children.

Liebig married Henriette "Jettchen" Moldenhauer (1807–1881), the daughter of a state official, in May 1826. They had five children, Georg (1827–1903), Agnes (1828–1862), Hermann (1831–1894), Johanna (1836–1925), and Marie (1845–1920). Although Liebig was Lutheran and Jettchen Catholic, their differences in religion appear to have been resolved amicably by bringing their sons up in the Lutheran religion and their daughters as Catholics.

Liebig and several associates proposed to create an institute for pharmacy and manufacturing within the university. The Senate, however, uncompromisingly rejected their idea, stating that training "apothecaries, soapmakers, beer-brewers, dyers and vinegar-distillers" was not the university's task. As of 17 December 1825, they ruled that any such institution would have to be a private venture. This decision actually worked to Liebig's advantage. As an independent venture, he could ignore university rules and accept both matriculated and unmatriculated students. Liebig's institute was widely advertised in pharmaceutical journals, and opened in 1826. Its classes in practical chemistry and laboratory procedures for chemical analysis were taught in addition to Liebig's formal courses at the university.

One of Liebig's frequent collaborators was Friedrich Wöhler. They met in 1826 in Frankfurt, after independently reporting on the preparation of two substances, cyanic acid and fulminic acid, that apparently had the same composition, but very different characteristics. The silver fulminate investigated by Liebig, was explosive, whereas the silver cyanate found by Wöhler, was not. After reviewing the disputed analyses together, they agreed that both were valid. The discovery of these and other substances led Jöns Jacob Berzelius to suggest the idea of isomers, substances that are defined not simply by the number and kind of atoms in the molecule, but also by the arrangement of those atoms.

A significant challenge facing 19th-century organic chemists was the lack of instruments and methods of analysis to support accurate, replicable analyses of organic materials. Many chemists worked on the problem of organic analysis, including French Joseph Louis Gay-Lussac and Swedish Jöns Jacob Berzelius, before Liebig developed his version of an apparatus for determining the carbon, hydrogen, and oxygen content of organic substances in 1830. It involved an ingenious array of five glass bulbs, called a Kaliapparat to trap the oxidation product of the carbon in the sample, following combustion of the sample. Before reaching the Kaliapparat, the combustion gases were conducted through a tube of hygroscopic calcium chloride, which absorbed and retained the oxidation product of the hydrogen of the sample, namely water vapor. Next, in the Kaliapparat, carbon dioxide was absorbed in a potassium hydroxide solution in the three lower bulbs, and used to measure the weight of carbon in the sample. For any substance consisting only of carbon, hydrogen, and oxygen, the percentage of oxygen was found by subtracting the carbon and hydrogen percentages from 100%; the remainder must be the percentage of oxygen. A charcoal furnace (a sheet-steel tray in which the combustion tube was laid) was used for the combustion. Weighing carbon and hydrogen directly, rather than estimating them volumetrically, greatly increased the method's accuracy of measurement. Liebig's assistant Carl Ettling perfected glass-blowing techniques for producing the Kaliapparat, and demonstrated them to visitors. Liebig's kaliapparat simplified the technique of quantitative organic analysis and rendered it routine. Brock suggests that the availability of a superior technical apparatus was one reason why Liebig was able to attract so many students to his laboratory. His method of combustion analysis was used pharmaceutically, and certainly made possible many contributions to organic, agricultural and biological chemistry.

In 1832, Liebig and Friedrich Wöhler published an investigation of the oil of bitter almonds. They transformed pure oil into several halogenated compounds, which were further transformed in other reactions. Throughout these transformations, "a single compound" (which they named benzoyl) "preserves its nature and composition unchanged in nearly all its associations with other bodies." Their experiments proved that a group of carbon, hydrogen, and oxygen atoms can behave like an element, take the place of an element, and can be exchanged for elements in chemical compounds. This laid the foundation for the doctrine of compound radicals, which can be seen as an early step in the development of structural chemistry.

In 1833, Liebig was able to convince chancellor Justin von Linde to include the institute within the university. In 1839, he obtained government funds to build a lecture theatre and two separate laboratories, designed by architect Paul Hofmann. The new chemistry laboratory featured innovative glass-fronted fume cupboards and venting chimneys. By 1852, when he left Giessen for Munich, more than 700 students of chemistry and pharmacy had studied with Liebig.

Although it was not widely adopted until after Liebig's death, when safety legislation finally prohibited the use of mercury in making mirrors, Liebig proposed a process for silvering that eventually became the basis of modern mirror-making. In 1835, he reported that aldehydes reduce silver salts to metallic silver. After working with other scientists, Carl August von Steinheil approached Liebig in 1856 to see if he could develop a silvering technique capable of producing high-quality optical mirrors for use in reflecting telescopes. Liebig was able to develop blemish-free mirrors by adding copper to ammoniated silver nitrate and sugar. An attempt to commercialize the process and "drive out mercury mirror-making and its injurious influence on workers' health" was unsuccessful.

Liebig was elected a member of the Royal Swedish Academy of Sciences in 1837.

He became a first-class member of the Ludwig Order, founded by Ludwig I, and awarded by Ludwig II on 24 July 1837.

In 1838, he became correspondent of the Royal Institute of the Netherlands; when that became the Royal Netherlands Academy of Arts and Sciences in 1851, he joined as foreign member.

The British Royal Society awarded him the Copley Medal "for his discoveries in organic chemistry, and particularly for his development of the composition and theory of organic radicals" in 1840.

Ludwig II of Bavaria conveyed the title of Freiherr von Liebig on 29 December 1845. In English, the closest translation is "Baron".

Building on his theories of the nutritional value of meat fluids, and seeking an inexpensive nutrition source for Europe's poor, Liebig developed a formula for producing beef extract. The details were published in 1847 so that "the benefit of it should ... be placed at the command of as large a number of persons as possible by the extension of the manufacture, and consequently a reduction in the cost".

In 1850, Liebig investigated spontaneous human combustion, dismissing the simplistic explanations based on ethanol due to alcoholism.

In 1850, he received the French Légion d'honneur, presented by chemist Jean-Baptiste Dumas, the French trade minister.

He was honored with the Prussian Order of Merit for Science by Friedrich Wilhelm IV of Prussia in 1851.

In 1852, Liebig accepted an appointment from King Maximilian II of Bavaria to the Ludwig Maximilian University of Munich. He also became scientific advisor to King Maxilimian II, who hoped to transform the University of Munich into a center for scientific research and development. In part, Liebig accepted the post because, at age 50, he was finding supervision of large numbers of laboratory students increasingly difficult. His new accommodations in Munich reflected this shift in focus. They included a comfortable house suitable for extensive entertaining, a small laboratory, and a newly built lecture theatre capable of holding 300 people with a demonstration laboratory at the front. There, he gave lectures to the university and fortnightly to the public. In his position as a promoter of science, Liebig was appointed president of the Bavarian Academy of Sciences and Humanities, becoming perpetual president of the Royal Bavarian Academy of Sciences in 1858.

Liebig enjoyed a personal friendship with Maximilian II, who died on 10 March 1864. After Maximilian's death, Liebig and other liberal Protestant scientists in Bavaria were increasingly opposed by ultramontane Catholics.

Production was not economically feasible in Europe, where meat was expensive, but in Uruguay and New South Wales, meat was an inexpensive byproduct of the leather industry. In 1865, Liebig partnered with Belgian engineer George Christian Giebert, and was named scientific director of the Liebig's Extract of Meat Company, located in Fray Bentos, Uruguay.

In 1869, he was awarded the Albert Medal by the Royal Society of Arts, "for his numerous valuable researches and writings, which have contributed most importantly to the development of food-economy and agriculture, to the advancement of chemical science, and to the benefits derived from that science by Arts, Manufactures, and Commerce."

Some organizations have granted medals in honor of Justus von Liebig. In 1871, the Versammlung deutscher Land- und Forstwirte (Assembly of German Farmers and Foresters) first awarded a Liebig Gold Medal, given to Theodor Reuning. The image was struck from a portrait commissioned in 1869 from Friedrich Brehmer.

Liebig died in Munich in 1873, and is buried in the Alter Südfriedhof in Munich.

The company also worked with British chemist Henry Enfield Roscoe to develop a related product, which it registered some years after Liebig's death, under the "Oxo" trademark. Oxo was trademarked worldwide in 1899 and in the United Kingdom in 1900. Originally a liquid, Oxo was released in cubed solid form in 1911.

In 1903, the Verein deutscher Chemiker (Association of German Chemists) also had a medal struck using Brehmer's portrait. Their Liebig Medal was first awarded in 1903 to Adolf von Baeyer, and in 1904 to Dr. Rudolf Knietsch of the Badische Ani-lin und Soda-Fabrik. As of 2014 it continues to be awarded.

In 1946, after the end of World War II, the University of Giessen was officially renamed after him, "Justus-Liebig-Universität Giessen".

In 1953, the West German post office issued a stamp in his honor.

In 1953, the third General Assembly of the International Scientific Centre of Fertilizers (CIEC), founded in 1932, was organized in Darmstadt to honor Justus von Liebig on the 150th anniversary of his birth.

At the third World Congress of CIEC, held at Heidelberg in 1957, the "Sprengel-Liebing Medal" was awarded to Dr. E. Feisst, president of CIEC, for outstanding contributions in agricultural chemistry.