Otto Wallach

Born March 27, 1847, in Königsberg; died Feb. 26, 1931, in Göttingen. German organic chemist.

Wallach graduated from the University of Göttingen in 1869. He was a privatdocent at the University of Bonn from 1873, a professor there from 1876, and then a professor at the University of Göttingen from 1889 to 1915. One of the pioneers of terpene chemistry, he began work in that field in 1884, guided by the idea that many natural terpenes consist of a mixture of monotypic hydrocarbons which cannot be separated by fractional distillation. By combining natural terpenes with various reagents (HCl, HBr, N₂0₃, N₂0₄, NOCl), Wallach obtained terpene addition compounds which crystallized easily and could therefore be separated. Wallach discovered and studied a series of terpene compounds (including limonene, phellandrene, terpineol, fenchone, methylheptanone, and terpinolene). He also demonstrated in 1891 the genetic link between terpenes and isoprene. He discovered the reaction of the reductive animation of aldehydes and ketones by primary and secondary amines and formic acid. Wallach was awarded the Nobel Prize in 1910.