Julius Tafel (chemist)

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Julius Tafel (born June 2, 1862 in Choindez ( Courrendlin municipality , then canton Bern, Switzerland ), † September 2, 1918 in Munich ) was a German chemist . He was the fourth child of the factory owner Julius Tafel and his wife Berta, nee. Kinzelbach.

Julius Tafel 1886 at Emil Fischer's old institute in Maxstrasse (fourth from the right, standing at the table)
Julius panel, ca.1888
Julius panel, ca.1905
Organic chemistry in Würzburg December 1909

Career

He attended the “Königlich Bayerische Realgymnasien im Kalkstadel” (now Willstätter-Gymnasium ) in Nuremberg and then studied chemistry in Zurich, Munich and Erlangen. He received his doctorate in 1884 under Emil Fischer and moved with him to do his habilitation in 1885 from Erlangen to Würzburg.

  • 1888 private lecturer in Würzburg,
  • 1898 Associate Professor (associate professor),
  • 1902 Associate Professor for Inorganic and Analytical Chemistry, University of Würzburg,
  • 1903 Full Professor and Head of the Chemical Institute at the University of Würzburg.

When Emil Fischer was working on the synthesis of carbohydrates, Tafel was his most important assistant - this work (1887–1889). Tafel also carried out the experiments when Fischer first reported on this work to the Chemical Society in Berlin in 1890. When Fischer went to Berlin, Hantzsch was his successor in Würzburg. Since Hantzsch moved to Leipzig in 1903, Tafel, who, as the successor of Wilhelm Wislicenus in 1902, had become a scheduled associate professor for inorganic and analytical chemistry in Würzburg, became his successor as full professor in Würzburg; Johannes Thiele had previously turned down the call for this position. In 1910 he had to retire from professional life due to his poor health. On the recommendation of Hantzsch, Alfred Werner received a call to succeed him, which he did not accept. Desperate about his incurable disease, Tafel voluntarily passed away in Munich in 1918.

Discoveries

The following terms in organic chemistry owe their name to Julius Tafel:

  • Tafel rearrangement in organic chemistry: the framework rearrangement discovered by Julius Tafel in 1907 during the electrolytic reduction of substituted acetoacetic esters in alcoholic sulfuric acid on a lead cathode.
  • Panel law or relationship: Electrochemistry: at a sufficiently high over-voltage of the logarithm of the current is a linear function of the surge (rather than overvoltage can also be voltage between the working and reference electrodes to say) (panel law or relation or relationship).
  • Panel pitch : Electrochemistry: the slope of the plot of (2) (panel slope); the application is called panel line in English
  • Tafel mechanism : Electrochemistry: in electrolytic hydrogen deposition, the mechanism in which hydrogen atoms (MH: M = metal atom of the electrode surface, H = hydrogen atom) adsorbed first under charge transfer are formed, which then recombine catalytically: 2 MH -> 2 M + H 2 (H 2 = a hydrogen molecule). (Panel mechanism.)
  • Electrocatalysis: In particular, Tafel found that the overvoltage for hydrogen separation (including recombination, see 4) on platinum is low, so that only hydrogen separation takes place on a platinum electrode in aqueous solution, but no reduction of organic substances; however, the overvoltage for hydrogen separation is very high on lead, so that organic substances can be reduced before hydrogen separation takes place; He gained this knowledge when he found that strychnine can be reduced on lead electrodes, which he used to determine its structure. Immediately afterwards he researched all this matter and thus became the founder of a branch of knowledge in electrochemistry, namely electrocatalysis. (Catalysis on metal surfaces was known, but the special relationships between electrodes = metal surfaces in solutions to which a voltage is applied, lead to completely new possibilities.) During his lifetime, these findings were largely ignored. He was ahead of his time and repeatedly found opportunities to criticize textbooks for failing to present modern aspects of the rate of reaction (the “theory of reaction rates”, for which he had laid the first basis with the table equation, only became systematic much later developed).

Predecessor at chem. Institutes in Würzburg

WÜ chem. Institute ca.1900.jpg
  • Joseph von Scherer (1842–1869 †; Juliusspital, from 1867 new chemical institute in Maxstrasse 4)
  • Adolph Strecker (1869-1871 †; Chem. Institute in Maxstr. 4)
  • Johannes Wislicenus (1872–1885; Chem. Institute in Maxstrasse 4)
  • Emil Fischer (1885–1892; Chem. Institute in Maxstrasse 4)
  • Wilhelm Wislicenus (1888–1902; Chem. Institute in Maxstrasse 4)
  • Arthur Hantzsch (1893–1903; Chem. Institute at Maxstrasse 4, from 1896 new Chem. Inst. At Pleicher Ring 11 - today Röntgenring)

Fonts

  • “About indazole and quinazole”, inaugural dissertation, Nuremberg / G. Dietz Verlag 1884, 8 °
  • "A new method of representing the amino bodies of the fat series", habilitation thesis, Würzburg / H. Stütz Verlag, 1888, 8 °, 60 pp.
  • "On Strychnine, First Treatise", March 1891.
  • "On Strychnine, Second Treatise," January 1892.
  • (Heinrich Günter) "Isomere 2,5-Diaminohexane 1892", Reports of the German Chemical Society Volume 28, Issue 1, pages 379–385, January – April 1895.
  • “Via what is known as indirect ester formation. Journal of Physical Chemistry ”, 1896.
  • (Gottlieb Fenner) "About 2-methylpyrrolidine", 1898.
  • "Reactivity of organic ammonium salts", 1898.
  • “About the polarization during cathodic hydrogen evolution”. Journal of Physical Chemistry, 1904.
  • (Bruno Emmert) "About the cause of the spontaneous depression of the cathode potential during the electrolysis of dilute sulfuric acid". Magazine for physics. Chemistry 1905.
  • (Hermann Stern) "About the diamino succinic acid ethyl ester". Wuerzburg, 1905.
  • (Paul Lavaczeck) “About Thio-pyrrolidone”. University of Würzburg 1905.
  • (Bruno Emmert) “On the knowledge of the electrolytic reduction of succinimide”. University of Würzburg 1905.
  • "Cathode potential and electrolytic reduction in sulfuric acid solution". Reprint from the Zeitschrift für Elektrochemie, 1906
  • "A strange formation of mercury alkyls". October 1906.
  • (Otto Wassmuth) "About pyrrolidone". Reports of the German Chemical Society Volume 40, Issue 3, pages 2831–2842, June – August 1907, Würzburg, June 1907.
  • (Paul Lavaczeck) "" ​​About Thio-Pyrrolidone II. 1907.
  • (Hans Hahl) "Complete reduction of the benzyl acetoacetic ester". Wuerzburg 1907.
  • "About intermediate products in chemical reactions". Wuerzburg 1907.
  • (Percy Alfred Houseman) “To the knowledge of the isopuron”. Würzburg, August 1907.
  • (Julius Dodt) "Reduction of theophylline and paraxanthine". Wuerzburg 1907.
  • (Julius Dodt) "Acidity of deoxyxanthines". Würzburg, August 1907.
  • (Herbert Bryan Thompson) "Electrolytic reduction of ethyl barbituric acids". October 1907
  • (Hans Hahl) "About the electrolytic reduction of hydroxylamine on copper cathodes". Chemists' newspaper 1908.
  • (Rudolf Mayer) "Hydrolysis of xanthines and deoxyxanthines". Wuerzburg 1908.
  • (Wilhelm Jürgens) "Representation of hydrocarbons through the electrolytic reduction of acetoacetic esters", Würzburg June 1909.
  • (Edward P. Frankland) "Diamino acids from deoxyxanthines", Würzburg August 1909.
  • "Electrolytic reduction of isoamyl-methyl-ketone to isoheptane."
  • "Unsaturated lead alkyls, University of Würzburg", January 1911.
  • (August Herterich) “1-methyl-deoxyxanthin University of Würzburg”, April 1911.
  • (Wilhelm Schepss) “On the electrolytic reduction of anisaldehyde.” University of Würzburg, July 1911.
  • “Formation of organometallic compounds during electrolytic reduction”, November 1912.

literature

  • Klaus Koschel: The development and differentiation of chemistry at the University of Würzburg. In: Peter Baumgart (Ed.): Four hundred years of the University of Würzburg. A commemorative publication. Degener & Co. (Gerhard Gessner), Neustadt an der Aisch 1982 (= sources and contributions to the history of the University of Würzburg. Volume 6), ISBN 3-7686-9062-8 , pp. 703–749; here: pp. 724–728.

Web links

Individual evidence

  1. ^ Klaus Koschel: The development and differentiation of the subject chemistry at the University of Würzburg. In: Peter Baumgart (Ed.): Four hundred years of the University of Würzburg. A commemorative publication. Degener & Co. (Gerhard Gessner), Neustadt an der Aisch 1982 (= sources and contributions to the history of the University of Würzburg. Volume 6), ISBN 3-7686-9062-8 , pp. 703–749; here: p. 725 f.
  2. ↑ Personal news in the journal for Angew. Chemie 23 , 1417 (1910).
  3. ↑ Successor to the chair in Würzburg: Eduard Buchner (1911–1917 †).
personal data
SURNAME Tafel, Julius
BRIEF DESCRIPTION German chemist
DATE OF BIRTH June 2, 1862
PLACE OF BIRTH Choindez , Switzerland
DATE OF DEATH September 2, 1918
Place of death Munich