Friedrich August Kekulé
(born: September 7, 1829 / died: July 13, 1896)
|Friedrich August Kekulé von Stradonitz
was a German organic chemist. He was born in Darmstadt. He was professor
at Ghent (1858-1865) and at Bonn. He studied various carbon compounds, especially
benzene, proposing a carbon ring for its structure. In 1857 Kekulé
proposed that carbon was tetravalent.
He wrote that he discovered the ring shape of the benzene molecule after dreaming of a snake seizing its own tail. This dream came to him after years of studying the nature of carbon-carbon bonds. Kekulé claimed to solve the problem of how carbon atoms could bond to up to four other atoms at the same time. While his claims were well publicized and accepted, by the early 1920s Kekulé's own biographer came to the conclusion that Kekulé's understanding of the tetravalent nature carbon bonding depended on the previous research of Archibald Scott Couper (1831-1892); further, the German chemist Josef Loschmidt (1821-1895) had earlier posited a cyclic structure for benzene as early as 1862, although he had not actually proved this structure to be correct.