22. Radical and Type Theories (1832-1850)

Freshman Organic Chemistry (CHEM 125)

Work by Wöhler and Liebig on benzaldehyde inspired a general theory of organic chemistry focusing on so-called radicals, collections of atoms which appeared to behave as elements and persist unchanged through organic reactions. Liebig's French rival, Dumas, temporarily advocated radicals, but converted to the competing theory of types which could accommodate substitution reactions. These decades teach more about the psychology, sociology, and short-sightedness of leading chemists than about fundamental chemistry, but both theories survive in competing schemes of modern organic nomenclature. The HOMO-LUMO mechanism of addition to alkenes and the SOMO mechanism of free-radical chain reactions are introduced.

00:00 - Chapter 1. Benzaldehyde and the Focus on Radicals
12:52 - Chapter 2. Dumas's "Note on the Present State of Organic Chemistry"
21:39 - Chapter 3. The Mystery of the Chlorinated Candle
34:59 - Chapter 4. Further Development of the Law of Substitution and the Theory of Types
47:35 - Chapter 5. Kolbe and the First Free Methyl Radical

Complete course materials are available at the Open Yale Courses website: http://open.yale.edu/courses

This course was recorded in Fall 2008.