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Home , Combustion analysis, Hermann Kolbe, Justus von Liebig, Robert Bunsen

Justus Liebig, Organic Analysis, and Chemical Pedagogy

Monday, October 4, 2010 Transformation of Organic , 1820-1850

• Enormous increase in the number of “organic” compounds • ~100 in 1820, thousands by 1860. • doubling approximately every nine years • The majority of these compounds are artificial. • Change in meaning of “organic” • Relative unimportant branch of chemistry to the largest and most important branch of chemistry • Natural history to experimental science • Chemistry as Wissenschaft, not an ancillary to medicine • Professionalization of

Monday, October 4, 2010 Transformation of Organic Chemistry, 1820-1850

Reasons for this transformation:

• Recognition of isomerism. • Explanation of isomerism by “arrangement.” • The rapid adoption of Berzelian notation as “paper tools” • Justus Liebig’s invention of the Kaliapparat for organic analysis

Monday, October 4, 2010 Analysis of Organic Compounds

CxHyOz+ oxygen ––> carbonic acid gas +

• carbonic acid gas = content • water = content • oxygen calculated by difference • determined by a separate :

CxHyOzNa+ oxygen ––> carbonic acid gas + nitrogen + water

Monday, October 4, 2010 Joseph Louis Gay-Lussac (1778-1850) Louis Jacques Thénard (1777-1857)

Monday, October 4, 2010 Monday, October 4, 2010 Jöns Jakob Berzelius (1779-1848)

Monday, October 4, 2010 Monday, October 4, 2010 (1800-1873)

Monday, October 4, 2010 Monday, October 4, 2010 Justus von Liebig

• Born 1803 in • 1821: University of Erlangen, influenced by Karl Wilhelm Gottlob Kastner • Intending a teaching career • October 1822-March 1824: Paris • Worked closely with Gay-Lussac on the composition of • Decides that he is capable of Wissenschaft, not just teaching • April 1824: Außerordentlicher Professor at University of Gießen.

Monday, October 4, 2010 Monday, October 4, 2010 Justus Liebig, Anleitung zur Analyse organischer Körper, 1837

Monday, October 4, 2010 Monday, October 4, 2010 Monday, October 4, 2010 Monday, October 4, 2010 Adoption of the Kaliapparat, 1830-1840

• Jean-Baptiste Dumas (Paris), 1832 • Berzelius (1835), Liebig’s method “leaves nothing to be desired.” • Friedrich Wöhler (Göttingen), 1831, the method is “superb.” • Bunsen, 1832 • Eilhard Mitserlich (Berlin) 1832 • Promotion through Annalen der Pharmacie (acquired by Liebig in 1831)

• 1837: Anleitung zur Analyse organischer Körper

Monday, October 4, 2010 Monday, October 4, 2010 Monday, October 4, 2010 Monday, October 4, 2010 Spreading the Liebig Teaching-Research Laboratory

• Friedrich Wöhler, 1841, Göttingen • , 1840, Marburg • Otto Erdmann, 1843, Leipzig • , Marburg, 1851 • August Wilhelm Hofmann, University College, London, 1845 • Dumas, Paris, 1838 (unsuccessful) • Eben Horsford, Harvard, 1846 (unsuccessful)

Monday, October 4, 2010 Spreading the Liebig Teaching-Research Laboratory

• Intensity of laboratory experience • All science students enrolled in Praktikum • Incorporation of Praktikum into the official university curriculum • Advanced Praktikanten and the development of the “research group” • Full integration of teaching and research

Monday, October 4, 2010