FRIEDRICH

See also:

• AUGUST (originally Sextilis)

AUGUST

See also:

• FRIEDRICH AUGUST KEKULE (1829-1896)

KEKULE (1829-1896)  , German chemist, was born at Darmstadt on the 7th of September 1829 . While studying architecture at Giessen he came under the influence of Liebig and was induced to take up chemistry . From Giessen he went to Paris, and then, after a short sojourn in Switzerland, he visited England . Both in Paris and in England he enjoyed personal intercourse with the leading chemists of the period . 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 1858 he was appointed professor of chemistry at Ghent, and in 1865 was called to Bonn to fill a similar position, which he held till his death in that town on the 13th of June 1896 . Kekule's main importance lies in the far-reaching contributions which he made to chemical theory, especially in regard to the constitution of the carbon compounds . The doctrine of atomicity had already been enunciated by E . Frankland, 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 substance, and some by an equal number of the affinities of the other carbon atoms . The simplest case is when two carbon atoms are combined so that one affinity of the one is tied to one affinity of the other; two, therefore, of the affinities of the two atoms are occupied in keeping the two atoms together, and only the remaining six are available for atoms of other elements . The next simplest case consists in the mutual interchange of two affinity units, and so on .

This conception led Kekule to his " closed-

chain " or " ring " theory of the constitution of benzene which has been called the " most brilliant piece of prediction to be found in the whole range of organic chemistry," and this in turn led in particular to the elucidation of the constitution of the " aromatic compounds," and in general to new methods of chemical synthesis and decomposition, and to a deeper insight into the composition of numberless organic bodies and their mutual relations . Professor F . R . Japp, in the Kekule memorial lecture he delivered before the London Chemical Society on the 15th of December 1897, declared that t hree-fourths of modern organic chemistry is directly or indirectly the product of Kekule's benzene theory, and that without its guidance and inspiration the industries of the coal-tar colours and artificial therapeutic agents in their present form and extension would have been inconceivable . Many of Keku16's papers appeared in the Annalen der Chemie, of which he was editor, and he also published an important work, Lehrbuch der organischen Chemie, of which the first three volumes are dated 1861, 1866 and 1882, while of the fourth only one small section was issued in 1887 .