Hofmann, August Wilhelm von

Hofmann, August Wilhelm von (ou`gst vĭl`hĕlm fən hôf`män), 1818–92, German organic chemist. He was professor at the Univ. of Berlin from 1865 and was a founder (1868) of the German Chemical Society. He studied the constitution of aniline and was the first to prepare rosaniline and its derivatives, thereby laying the basis for the aniline dye industry. He also discovered a reaction for deriving amines from amides and developed the Hofmann method of finding the vapor densities, and from these the molecular weights, of liquids. He also helped to popularize the concept of valence (the word comes from his term quantivalence).