Friedrich August Kekule von Stradonitz (also August Kekulé) (September 7, 1829 – July 13, 1896) was a German organic chemist. One of the most prominent organic chemists in Europe from the 1850s until his death, especially in the theoretical realm, he was the principal founder of the theory of chemical structure. Image File history File links File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... September 7 is the 250th day of the year (251st in leap years). ... Johann Wolfgang von Goethe 1829 was a common year starting on Thursday (see link for calendar). ... July 13 is the 194th day (195th in leap years) of the year in the Gregorian Calendar, with 171 days remaining. ... Year 1896 (MDCCCXCVI) was a leap year starting on Wednesday (link will display calendar). ... Organic chemistry is a specific discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of chemical compounds consisting of primarily carbon and hydrogen, which may contain any number of other elements, including nitrogen, oxygen, halogens as well...

His Name

Kekulé never used his first given name; he was known throughout his life as August Kekulé. After he was ennobled by the Kaiser in 1895, he adopted the name August Kekule von Stradonitz, without the French accent aigue over the second "e". The French accent had apparently been added to the name by Kekulé's father during the Napoleonic occupation of Hesse by France, in order to indicate that the name had three syllables, and not just two (as a Frenchman would presume from the spelling).

Early life

Kekulé was born in Darmstadt, the son of a civil servant. After graduating from secondary school, in 1847 he entered the University of Giessen, with the intention of studying architecture. After hearing the lectures of Justus von Liebig he decided to study chemistry. Following his education in Giessen, he took postdoctoral fellowships in Paris (1851-52), in Chur, Switzerland (1852-53), and in London (1853-55), where he was decisively influenced by Alexander Williamson. Darmstadt is a city in the Bundesland (federal state) of Hessen in Germany. ... Gießen (Giessen pronunciation) is a city in the federal state (Bundesland) of Hesse in Germany, capital of the Gießen district. ... Freiherr Justus von Liebig (May 12, 1803 in Darmstadt, Germany – April 18, 1873 in Munich, Germany) was a German chemist who made major contributions to agricultural and biological chemistry, and worked on the organization of organic chemistry. ... There have been several persons named Alexander Williamson. ...

Career

In 1856 Kekulé became Privatdozent at the University of Heidelberg. In 1858 he was hired as full professor at the University of Ghent, then in 1867 was called to Bonn, where he remained for the rest of his career. Basing his ideas on those of predecessors such as Williamson, Edward Frankland, William Odling, Charles Adolphe Wurtz and others, Kekulé was the principal formulator of the theory of chemical structure (1857-58). This theory proceeds from the idea of atomic valence, especially the tetravalence of carbon (which Kekulé announced late in 1857) and the ability of carbon atoms to link to each other (which he announced in May 1858), to the determination of the bonding order of all of the atoms in a molecule. Archibald Scott Couper independently arrived at the idea of self-linking of carbon atoms (his paper appeared in June 1858), and provided the first molecular formulas where lines symbolize bonds connecting the atoms. The Ruprecht Karl University of Heidelberg (German Ruprecht-Karls-Universität Heidelberg; also known as simply University of Heidelberg) was established in the town of Heidelberg in the Rhineland in 1386. ... Ghent University (in Dutch, Universiteit Gent, abbreviated UGent) is one of the three large Flemish universities. ... The main building, viewed from the Hofgarten. ... Sir Edward Frankland (January 18, 1825 – August 9, 1899) was an English chemist. ... William Odling (1829 - 1921) was an English chemist who contributed to the development of the periodic table. ... Charles Adolphe Wurtz (November 26, 1817 - May 10, 1884) was a French chemist. ... Archibald Scott Couper (1831-1892) was the author of On a New Chemical Theory, Philosophical Magazine 16, 104-116 (1858) [as excerpted in Alembic Club Reprint #21, On a New Chemical Theory and Researches on Salicylic Acid[1]] Friedrich August Kekulé von Stradonitz claimed to solve the structure of Benzene...

For organic chemists, the theory of structure provided dramatic new clarity of understanding, and a reliable guide to both analytic and especially synthetic work. As a consequence, the field of organic chemistry developed explosively from this point. Among those who were most active in pursuing structural investigations were, in addition to Kekulé, Frankland, Wurtz, Alexander Crum Brown, Emil Erlenmeyer, and Aleksandr Mikhailovich Butlerov Extract from Alexander Crum Browns influential paper. ... Photograph of Richard August Carl Emil Erlenmeyer Richard August Carl Emil Erlenmeyer (28 June 1825 – 22 January 1909) was a German chemist, usually known simply as Emil Erlenmeyer. ... Aleksandr Mikhailovich Butlerov (Александр Михайлович Бутлеров) (September 15, 1828 – August 17, 1886, Russian chemist, the creator of the theory of chemical structure (1861), and the...

Kekulé's most famous work was on the structure of benzene. In 1865 Kekulé published a paper in French (for he was then still in Francophone Belgium) suggesting that the structure contained a six-membered ring of carbon atoms with alternating single and double bonds. The next year he published a much longer paper in German on the same subject.^[1] The empirical formula for benzene had been long known, but its highly unsaturated structure was challenging to determine. Archibald Scott Couper in 1858 and Joseph Loschmidt in 1861 suggested possible structures that contained multiple double bonds or multiple rings, but the study of aromatic compounds was in its very early years, and too little evidence was then available to help chemists decide on any particular structure. Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... Archibald Scott Couper (1831-1892) was the author of On a New Chemical Theory, Philosophical Magazine 16, 104-116 (1858) [as excerpted in Alembic Club Reprint #21, On a New Chemical Theory and Researches on Salicylic Acid[1]] Friedrich August Kekulé von Stradonitz claimed to solve the structure of Benzene... Jan or Johann Josef Loschmidt (March 15, 1821 - July 8, 1895) who referred to himself mostly as Josef Loschmidt (omitting his first name), was a notable Austrian scientist with groundbreaking work in the fields of chemistry and physics (thermodynamics, optics, electrodynamics). ...

Kekulé used evidence that had accumulated in the intervening years to argue in support of his proposed structure -- namely, that there always appeared to be only one isomer of any monoderivative of benzene, and that there always appeared to be exactly three isomers of every diderivative. Kekulé's symmetrical ring could explain these curious facts.

The new understanding of benzene, and hence of all aromatic compounds, proved to be so important for both pure and applied chemistry that in 1890 the German Chemical Society organized an elaborate appreciation in Kekulé's honor, celebrating the twenty-fifth anniversary of his first benzene paper. Here Kekulé spoke of the creation of the theory. He said that he had discovered the ring shape of the benzene molecule after having a reverie or day-dream of a snake seizing its own tail (this is a common symbol in many ancient cultures known as the Ouroboros). This vision, he said, came to him after years of studying the nature of carbon-carbon bonds. It is curious that a similar humorous depiction of benzene had appeared in 1886 in the Berichte der Durstigen Chemischen Gesellschaft (Journal of the Thirsty Chemical Society), a parody of the Berichte der Deutschen Chemischen Gesellschaft, only the parody had monkeys seizing each other in a circle, rather than snakes as in Kekulé's anecdote.^[2] Some historians have suggested that the parody was a lampoon of the snake anecdote, possibly already well-known through oral transmission even if it had not yet appeared in print.^[3] Others have speculated that Kekulé's story in 1890 was a re-parody of the monkey spoof, and was a mere invention rather than a recollection of an event in his life.

Kekulé's 1890 speech^[4] in which these anecdotes appeared has been translated into English.^[5] If one takes the anecdote as the memory of a real event, circumstances mentioned in the story suggest that it must have happened early in 1862.^[6] The other anecdote he told in 1890, of a vision of dancing atoms and molecules that led to his theory of structure, happened (he said) while he was riding on the upper deck of a horse-drawn omnibus in London. If true, this must have occurred in 1855.

Honors

In 1895 Kekulé was ennobled by Kaiser Wilhelm II of Germany, giving him the right to add "von Stradonitz" to his name, referring to an ancient possession of his family in Stradonice, Bohemia. Of the first five Nobel Prizes in Chemistry, his students won three. German Emperor Wilhelm (born Friedrich Wilhelm Viktor Albrecht, Prince of Prussia 27 January 1859–4 June 1941), was the last German Emperor and King of Prussia (de: Deutscher Kaiser und König von Preußen), ruling from 15 June 1888 to 9 November 1918. ... The Nobel Prizes (Swedish: ) are awards in physics, chemistry, literature, peace, and physiology or medicine. ...

See also

• Benzene
  

  

  Stamp
• Non-Kekulé molecule
• Kekulé Program

Benzene, also known as benzol, is an organic chemical compound with the formula C6H6. ... A non-Kekulé molecule is a conjugated hydrocarbon that cannot be assigned classical Kekulé structures. ...

External links

• Kekulés Traum (Kekulé's dream, in German)
• Pronunciation of Kekulé
• Kekulé: A Scientist and a Dreamer

References

1. ^ Kekulé, "Sur la constitution des substances aromatiques," Bulletin de la Societe Chimique de Paris,[2] 3 (January 1865), 98-110; "Untersuchungen uber aromatische Verbindungen," Liebigs Annalen der Chemie, 137 (1866), 129-36.
2. ^ Translated into English by D. Wilcox and F. Greenbaum, Journal of Chemical Education, 42 (1965), 266-67.
3. ^ A. J. Rocke, "Hypothesis and Experiment in Kekulé's Benzene Theory," Annals of Science, 42 (1985), 355-81.
4. ^ Kekulé, "Benzolfest: Rede," Berichte der Deutschen Chemischen Gesellschaft, 23 (1890), 1302-11.
5. ^ O. T. Benfey, "August Kekulé and the Birth of the Structural Theory of Organic Chemistry in 1858," Journal of Chemical Education, 35 (1958), 21-23
6. ^ Jean Gillis, "Auguste Kekulé et son oeuvre, realisee a Gand de 1858 a 1867," Memoires de l'Academie Royale de Belgique, 37:1 (1866), 1-40.