KEKULE, FRIEDRICH AUGUST German chemist, was born at Darmstadt on Sept. 7, 1829. He studied architecture at Giessen and later, coming under the influence of Liebig, he took up chemistry. From Giessen he went to Paris, and then visited England where he enjoyed personal intercourse with the leading chemists. On his return to Germany he started a small chemical laboratory at Heidelberg, where, with a very slender equipment, he carried out several important researches. In 1856 he became assistant professor of chemistry at Heidelberg, and in 1858 professor at Ghent; in 1865 he was called to Bonn to fill a similar position, which he held till his death on June 13, 1896. Kekule's main importance lies in the far-reaching contributions which he made to chemical theory, especially in regard to the con stitution of the carbon compounds (see CHEMISTRY: Organic). The doctrine of atomic saturation capacity (valency) had already been enunciated by E. Frankland (q.v.), when in 1858 Kekule published a paper in which, after giving reasons for regarding carbon as a tetravalent element, he set forth the essential features of his famous doctrine of the linking of atoms. He explained that in substances containing several carbon atoms it must be assumed that some of the affinities of each carbon atom are bound by the affinities of the atoms of other elements contained in the sub stance, and some by an equal number of the affinities of the other carbon atoms. This conception led Kekule in 1865 to formulate
his "closed-chain" or "ring" theory of the constitution of benzene (q.v.), which has been called the "most brilliant piece of predic tion to be found in the whole range of organic chemistry." This in turn led to the elucidation of the constitution of the "aromatic compounds." These contributions to the theory of chemical struc ture are so important that Kekule's other valuable work on ful minate of mercury, and on unsaturated and thio-acids, etc., ap pears insignificant in comparison. Professor F. R. Japp, in the Kekule memorial lecture (Journ. Chem. Soc., 1898), declared that three-fourths of modern organic chemistry is directly or indirectly the product of Kekule's benzene theory.
Many of Kekule's papers appeared in the Annalen der Chemie, of which he was editor, and he also published an important work, Lehr buch der organischen Chemie, of which the first three volumes are dated 1861, i866 and 1882, while of the fourth only one small section was issued in 1887.