Karlsruhe Congress

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The Karlsruhe Congress was the first international symposium of modern chemistry. It took place from September 3rd to 5th, 1860 on the initiative of Friedrich August Kekulé von Stradonitz , Charles Adolphe Wurtz and Karl Weltzien in the Ständehaus in Karlsruhe . Topics were the nomenclature of chemical compounds and their formulaic representation as well as the question of the atomic and molecular weights of chemical compounds. It was the first international symposium for chemistry worldwide.

occasion

Chemistry was established as a scientific discipline in the mid-19th century and still had a considerable theoretical deficit. In particular, when it comes to atomic and molecular construction, different "schools" represented different views. According to John Dalton, they were generally accepted as the smallest building blocks of chemical compounds, but almost nothing was known about their structure. Different views were also held on other fundamental theoretical questions such as the basic size of atomic weights. The nomenclature and formulas were also highly inconsistent. However, there was as yet no forum in which the current problems could be discussed. That is why three young chemistry professors took the initiative to organize a congress in order to clarify the disputed questions in a discourse with specialist colleagues, and invited the most important representatives of the subject to Karlsruhe from September 3rd to 5th, 1860. The geographical location of Karlsruhe meant that a large number of French chemists would take part, and the Karlsruhe Technical University already had a good reputation at that time.

The “organic chemistry” before the Karlsruhe Congress

Acetic acid formulas
Fig. In chemistry didactics today

Formula representation of the molecules

After the first syntheses of organic substances by Wöhler ( oxalic acid through hydrolysis of dicyan in 1824 and urea from ammonium cyanate in 1828) a stormy investigation of organic molecules began. The textbook by H. Kolbe , published in 1854 , which already comprised more than a thousand pages, gives a nice overview .

However, there was no agreement on the formulaic representation of these. An example is the formulas for acetic acid given in Kekulé's textbook on organic chemistry. Nineteen different representations of this acid were common.

Atomic and molecular weights

Atomic weights
A substance name
B symbol according to Berzelius
C atomic weight of hydrogen s = 1
D atomic weight of oxygen = 100
E according to Berzelius, simple hydrogen = 0.5, "double atom" = 1
F according to Berzelius, oxygen = 100
Table from relationship: Johann Samuel Traugott Gehler's physical Dictionary 1840 , p. 1912

There was also no agreement on atomic and molecular weights. Based on the findings of

and ultimately the atomic hypothesis of Dalton (1803), there was agreement that atoms are discrete particles and molecules are built up from them, but several systems of atomic weights were used side by side. One was based on hydrogen, to which the value 1 was assigned as the base unit , 6 to carbon and 8 to oxygen . As long as there were uncertainties about the atomic weights, the elemental composition of the compounds examined was questionable. An example of the chaos that prevailed in atomic weights before 1850 is shown in the diagram opposite.

course

127 chemists traveled from Europe and overseas, including famous names such as Robert Bunsen , Adolf von Baeyer , Emil Erlenmeyer , Hermann von Fehling , Carl Remigius Fresenius , Hermann Kopp , Friedrich Konrad Beilstein , Jean-Baptiste Boussingault , Jean-Baptiste Dumas , Stanislao Cannizzaro , Dmitri Iwanowitsch Mendelejew and Lothar Meyer . The congress officially opened on Monday, September 3rd at 9:00 a.m. The conference took place in the large meeting room of the Karlsruhe Estates House , which was the first parliamentary building on German soil to be the meeting place for the representatives of Baden.

The conference was organized as follows: Weltzien chaired the first session on September 3, at which Kekulé, Lev Nikolajewitsch Schischkow, Henry Enfield Roscoe, Adolf Strecker and William Odling were named as the minutes' keepers of the conference. Then at 11 o'clock a nine-member commission, chaired by Kopp, met with exclusion of the conference public to specify the topics to be dealt with at the congress. The committee agreed on the distinction to be made between "atom", "molecule" and "equivalent". A congress dinner was held in the evening. The next day the meeting discussed the questions formulated by the committee, but without arriving at a tangible result. The disputed issues were therefore returned to the commission, which discussed them twice that day and then decided to submit three specific nomenclature questions to the assembly for decision. On Wednesday, September 5th, the Congress, chaired by Dumas, discussed the questions on the nomenclature and use of chemical symbols that had been decided by the Commission the previous day. The until then little-known Genoese chemistry professor Cannizzaro warned against attempting to trace back the state of knowledge to the time before Berzelius , since chemistry has been continuously expanded since then. After a controversial discussion, the Congress finally decided that the crossed-out symbols introduced by Berzelius should also be used in the future. Then Dumas ended the meeting as chairman.

Results

The Karlsruhe Congress was the first specialist congress of a natural science discipline. Even if there were no radical results, the Karlsruhe Chemists' Congress can be considered the most important event in the history of chemistry in the 19th century. The meeting of so many chemists from home and abroad had a catalytic effect on the further development of theoretical chemistry. In particular, the general acceptance of the Avogadro-Ampère theory and the subsequent development of the periodic table were promoted by the congress.

Individual evidence

  1. ↑ Hans-Dieter Barke, Günther Harsch: Chemiedidaktik heute: Learning processes in theory and practice. Springer, Berlin 2001, p. 510, ISBN 3-540-41725-7 .
  2. ^ Burckhard Frank: 250 years of chemistry in Göttingen . In: Hans-Heinrich Voigt (Ed.): Natural sciences in Göttingen. A series of lectures . Vandenhoeck + Ruprecht Gm, Göttingen 1988, ISBN 3-525-35843-1 ( Göttinger Universitätsschriften . Volume 13), p. 72 ( preview ; preview ).
  3. ↑ F. Wöhler to Berzelsius (August 22, 1828): ... I have to tell you that I can make urea without having kidneys or an animal at all, whether human or dog. ibid, p. 212, ( Google Books ).
  4. ↑ H. Kolbe et al .: Graham-Otto's Detailed Textbook of Chemistry. Vieweg-Verlag, Braunschweig, 1854
  5. ^ Hermann Kolbe et al .: Comprehensive textbook on organic chemistry . Vieweg, 1854 ( Google books ).
  6. ↑ Johann Samuel Traugott Gehler, Karl Ludwig Littrow: Johann Samuel Traugott Gehler's Physical Dictionary: Bd., 1. abth… EB Schurckert, 1839, ISBN 3-13-449609-7 , p. 1912 ( limited preview in Google Book Search).
  7. ↑ In a chemical reaction, elements are neither lost nor are new elements created.
  8. ↑ For azobenzene the formula C 24 H 10 N 2 was suggested at times , P. Hofmann : Annalen der Chemie und Pharmacie CXV. P. 362.
  9. ^ Aaron John Ihde: The Development of Modern Chemistry , Courier Dover Publications, 1984, p. 203, ISBN 0-486-64235-6 ( Google Books ).

literature

  • Festival ceremony for the 40th anniversary of His Royal Highness the Grand Duke Friedrich von Baden's reign. Karlsruhe, 1892. - LXXXVIII, 373 p. PDF
  • A. Stock: The international chemists' congress Karlsruhe 3.-5. September 1860 in front of and behind the scenes . Verlag Chemie, Berlin: 1933. PDF
  • C. deMilt: The Congress at Karlsruhe In: J. Chem. Educ. 1951, 28, pp. 421-425
  • AJ Ihde: The Karlsruhe Congress: A Centennial Retrospect In: J. Chem. Educ. 1961, 38, pp. 83-86.
  • Ch. Hartley: Stanislao Cannizzaro, FRS (1826-1910) and the First International Chemical Conference at Karlsruhe in 1860. In: Notes and Records of the Royal Society of London, 1966, 21, pp. 56-63.
  • AJ Rocke: Nationalizing Science: Adolphe Wurtz and the Battle for French Chemistry . MIT Press, 2001. ISBN 0-262-18204-1 , pp. 226-233.

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