Encyclopedia, Difference between revisions of "August Kekulé" - New World

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[[Image:Frkekulé.jpg|framed|Friedrich August Kekule von Stradonitz]]
 
[[Image:Frkekulé.jpg|framed|Friedrich August Kekule von Stradonitz]]
  
'''Friedrich August Kekule von Stradonitz''' (also '''August Kekulé''') ([[September 7]], [[1829]] – [[July 13]], [[1896]]) was a [[Germany|German]] [[organic chemistry|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.
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'''Friedrich August Kekule von Stradonitz''' (also '''August Kekulé''') (September 7, 1829 – July 13, 1896) was a [[Germany|German]] [[organic chemistry|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.
  
 
==His Name==
 
==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).
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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==
 
==Early life==
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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]]
 
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]]
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[[Image:kekuleelek.jpg|thumb|250px|German stamp honoring Kekulé.]]
  
 
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.<ref>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.</ref>  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.
 
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.<ref>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.</ref>  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.
  
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.
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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.<ref>Translated into English by D. Wilcox and F. Greenbaum, ''Journal of Chemical Education'', 42 (1965), 266-67.</ref> 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.<ref>A. J. Rocke, "Hypothesis and Experiment in Kekulé's Benzene Theory," ''Annals of Science'', 42 (1985), 355-81.</ref>  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.
 
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.<ref>Translated into English by D. Wilcox and F. Greenbaum, ''Journal of Chemical Education'', 42 (1965), 266-67.</ref> 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.<ref>A. J. Rocke, "Hypothesis and Experiment in Kekulé's Benzene Theory," ''Annals of Science'', 42 (1985), 355-81.</ref>  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.
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== See also ==
 
== See also ==
*[[Benzene]] [[Image:kekuleelek.jpg|thumb|150px|Stamp]]
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*[[Benzene]]
 
*[[Non-Kekulé molecule]]
 
*[[Non-Kekulé molecule]]
 
*[[Kekulé Program]]
 
*[[Kekulé Program]]
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[[Category:German chemists|Kekulé von Stradonitz, Friedrich August]]
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[[fr:Friedrich Kekulé von Stradonitz]]
 
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[[gl:Friedrich August Kekulé von Stradonitz]]
 
[[ko:프리드리히 아우구스투스 케쿨레 폰 슈트라도니츠]]
 
[[id:Friedrich August Kekulé von Stradonitz]]
 
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Revision as of 14:30, 28 March 2007

Friedrich August Kekule von Stradonitz

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.

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.

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.

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

German stamp honoring Kekulé.

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.

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.

See also

  • Benzene
  • Non-Kekulé molecule
  • Kekulé Program

External links

References
ISBN links support NWE through referral fees

  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.

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