Hermann Kolbe

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Hermann Kolbe
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Adolph Wilhelm Hermann Kolbe (born September 27, 1818 in Elliehausen , today a district of Göttingen , † November 25, 1884 in Leipzig ) was a German chemist . With the electrolysis of carboxylic acids he discovered a possibility of linking the alkyl radicals of acids and for the first time produced salicylic acid from phenolate and carbon dioxide .

resume

Kolbe was the eldest of 15 children of pastor Karl Kolbe (1780 - 1870) and his wife Auguste born. Hempel (born 1800). He received his first lessons in his parents' rectory. Due to the father's change of activity, the family moved to Stöckheim in the Leinetal in 1826. He attended high school in Göttingen from 1831 and passed the Abitur there in 1838. After studying chemistry from 1838 with Friedrich Wöhler in Göttingen, he became assistant to Robert Wilhelm Bunsen at the University of Marburg in 1842 . During his studies and later as an assistant in Marburg, he wrote numerous scientific treatises and published his first publications. He had also started his dissertation in Göttingen, which he then completed in Marburg. In the autumn of 1843 he received his doctorate ( Dr. rer. Nat. ) For his work on the products of the action of chlorine on carbon disulfide . From 1845 to 1847 Kolbe was an assistant at Lyon Playfair at the University of London . Here he supported Playfaier at the Museum for Economic Geology with firedamp investigations. During this time he also made friends with Edward Frankland . In London, Kolbe and Frankland discovered the method of preparing carboxylic acids from nitriles. The electrolysis of carboxylic acids with the formation of carbon dioxide and the dimerized alkanes also fell into this period (in 1847 Kolbe also worked in Marburg near Bunsen).

In the autumn of 1847, Kolbe went to Braunschweig to work on the concise dictionary of chemistry because of an offer from Fr. Vieweg & Sohn .

In 1851 Kolbe followed the call to the professorship for chemistry at the University of Marburg as the successor to Robert Bunsen. In 1853 Kolbe married Charlotte von Bardeleben (1832 - 1876). The marriage resulted in a son and three daughters. The son Karl Kolbe (1856 - 1909) also became a chemist and in 1884 took over the salicylic factory "Dr.FvHeyden" as director, of which Hermann Kolbe was a partner. In 1865 he became a full professor at the University of Leipzig . The chemical institute of the University of Leipzig was built here in 1868 according to his plans. From 1870 he was the editor of the journal "Journal of practical chemistry" founded by Otto Linné Erdmann .

Scientific work

When Kolbe began studying chemistry, organic chemistry as a science was relatively unknown. From elemental analyzes initiated chemist the relative contents of carbon, hydrogen and oxygen in an organic compound from, was completely unknown at this time their structure and the nature of the atomic exchange of molecules in a chemical reaction. In this phase, many material conversions were investigated with the aim of discovering a certain order from the change in the elemental composition and drawing conclusions about the chemical constitution and reaction behavior of compounds.

After the dualistic radical theory (with a positive and a negative area in each inorganic and organic particle) of Jöns Jacob Berzelius in organic chemistry was shaken by a unitarian type theory through the discovery of substitution by Jean Baptiste Dumas , there were two camps in organic chemistry Chemistry. One camp ( Charles Gerhardt , Auguste Laurent ) tried to further develop the type theory through new considerations, the other camp tried to reform Berzelius' dualistic theory through conceptual auxiliary constructs. Kolbe initially supported the dualistic theory of Berzelius, he was one of the strongest defenders of the dualistic system of Berzelius (see also history of the substitution reaction ). Kolbe investigated the conversion of carbon disulfide with chlorine for his dissertation (1842–1843) . In addition to the organic chlorine compounds, he also received a crystalline substance, trichloromethanesulfonic acid. Kolbe was able to derive their origin from the dualistic theory. Treatment with sodium amalgam enabled all chlorine atoms to be exchanged for hydrogen atoms, so that methanesulfonic acid was formed. A little later, Kolbe found out that tetrachlorethylene (produced from carbon tetrachloride when passed through a glowing tube) was converted to trichloroacetic acid in sunlight in the presence of water and chlorine. The trichloroacetic acid could be converted into acetic acid with sodium amalgam . In his article, the word synthesis was first used in the field of organic chemistry. At that time, Kolbe hoped that in the future, organic chemistry could be used to manufacture complex substances such as sugar from simple substances such as acetic acid. In his work a new carbon-carbon bond was made, the chlorine substituents on the carbons were replaced by hydrogen and oxygen.

Kolbe visited his friend Edward Frankland in London . A new synthesis of carboxylic acids was worked out with Frankland. They synthesized the corresponding carboxylic acids from the alkyl cyanides ( acetonitrile , ethyl nitrile first synthesized by Dumas and Théophile-Jules Pelouze ) by saponification. Kolbe and Frankland now assumed that the cyano compounds are carboxylic acids paired with radicals. In their view, hydrogen cyanide corresponded to oxalic acid (carboxy group), acetonitrile to acetic acid. Kolbe now wanted to know whether the methyl radical can be split off from acetic acid and whether a pure radical can possibly be produced. To do this, he electrolyzed acetic acid. A substance with the chemical composition for a methyl radical and carbon dioxide was actually created at the positive pole. However, the molar mass for the methyl radical was higher than expected, ethane was formed. Kolbe was now sure that acetic acid consists of two radical pairs: the carbonic acid and the methyl radical. He also electrolyzed the higher alkanoic acids and was also able to detect carbon dioxide and alkane formation in these (see Kolbe electrolysis ). Because of the electrochemical experiments, Kolbe again supported Berzelius' dualistic theory. After Frankland's ideas for the saturation capacities of the elements, Kolbe revised the radical theory.

In this work he saw all organic substances as derivatives of carbonic acid, which were created by substitution processes. Kolbe changed Gerhardt's formal type theory to a real type theory; he described Gerhardt's type theory as an unscientific formula game. Kolbe rejected Gerhardt's thesis that a chemical compound could have several constitutional formulas. From his theory he predicted the possibility of the existence of secondary and tertiary alcohols.

These alcohols were discovered a few years later by Alexander Butlerow and Charles Friedel . Kolbe also examined the isomerism of fatty acids and clarified the constitution of lactic acid , alanine, and malic and tartaric acid . Kolbe also succeeded in producing the first aliphatic nitro compound ( nitromethane ).

For medicine, Kolbe's development of a simple synthesis for salicylic acid (acetylsalicylic acid (aspirin) is a derivative of salicylic acid) was particularly important. He produced salicylic acid from phenol in the presence of carbon dioxide and sodium . However, it was only Rudolf Schmitt who fully elucidated the formation of salicylic acid .

By bringing in his Kolbe synthesis , he became a partner in the salicylic acid factory founded by Friedrich von Heyden in 1874. F. v. Heyden , who for the first time ever produced pharmaceuticals synthesis on an industrial scale in Radebeul . His son Carl Kolbe , also a chemist, took over the management in 1884 and the factory from its founder in 1885. His daughter Johanna married the chemist Ernst von Meyer . His nephew Hermann Ost , son of his sister Bertha, also became a chemist and professor at the TH Hannover . And his grandson Ferdinand Hermann Krauss also became a professor of chemistry.

Teaching and University

Kolbe wrote an extensive textbook on organic chemistry (1854–1865). There is also a short textbook on inorganic and organic chemistry.

He was editor (since 1870) of the journal Journal for practical chemistry founded by OL Erdmann .

Between 1847 and 1851 he worked on the concise dictionary of pure and applied chemistry at Vieweg Verlag in Braunschweig.

The chemical institute in Leipzig was built according to his plans in 1868.

As a teacher, he used a method of learning that encouraged careful observation and thought in the student.

Ernst Otto Beckmann , Alexander Michailowitsch Saizew and Theodor Curtius were among his students and colleagues in Leipzig .

Awards

Memorial plaque of the GDCh at the chemical factory v. Heyden, Meißner Strasse 35 in Radebeul

Kolbe was appointed Privy Councilor for his work . In 1877 he was awarded in Tübingen the Dr. med. hc

In 1862 he was elected a foreign member of the Bavarian Academy of Sciences . In addition, Kolbe was a member or honorary member of several scientific institutions, such as the Royal Saxon Society of Sciences , the Prussian Academy of Sciences , the Universities of Kazan and Kiev and the Royal Society in Edinburgh .

From 1872 Kolbe was knight of the Bavarian Maximilian Order for Science and Art and received the Davy Medal from the Royal Society in 1884 .

Since October 1, 2012, the former salicylic acid factory and later chemical factory Dr. F. von Heyden one of the historical sites of chemistry , awarded by the Society of German Chemists (GDCh) as part of a ceremony with a plaque on the main building in Radebeul. This reminds of the work of Jacob Friedrich von Heyden , Adolph Wilhelm Hermann Kolbe, Rudolf Wilhelm Schmitt , Bruno Richard Seifert and Richard Gustav Müller .

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Web links

Commons : Hermann Kolbe  - collection of images, videos and audio files

Individual evidence

  1. ↑ Dear. Ann. d. Chem. 41 , 41
  2. ↑ Ann. Chem. 54 , 156
  3. ↑ Ann. Chem. 75 , 211
  4. ↑ Ann. Chem. 76 , 1
  5. ↑ Dear. Ann. d. Ch. 65 , 288 (1848)
  6. ↑ a b Hermann Kolbe: Investigations into the electrolysis of organic compounds . In: Friedrich Wöhler, Justus Liebig (Ed.): Annals of Chemistry and Pharmacy . tape 69 , no. 3 . CF Winter, Heidelberg 1849, p. 257–294 , doi : 10.1002 / jlac.18490690302 ( online in the Internet Archive ): "To obtain important information about their chemical constitution through the electrolytic decomposition of organic compounds."
  7. ↑ Dear. Ann. d. Ch. 75 , 211 (1851)
  8. ↑ Dear. Ann. d. Ch. 76 , 1 (1851)
  9. ↑ Dear. Ann. d. Ch. 113 , 293 (1859)
  10. ↑ Dear. Ann. d. Ch. 113 , 307 (1859)
  11. ^ The chemical laboratory of the University of Marburg (Braunschweig 1865), by Hermann Kolbe
  12. ↑ Dear. Ann. d. Chem. 171 , 1; 175 , 88; 180 , 111
  13. ↑ Dear. Ann. d. Ch. 113 , 125 (1859)
  14. ↑ Dear. Ann. d. Ch. 115 , 201
  15. ^ Journ. pr. Chem (2) 31 , 397
  16. ^ Member entry by Hermann Kolbe (with picture) at the Bavarian Academy of Sciences , accessed on February 9, 2016.


personal data
SURNAME Kolbe, Hermann
ALTERNATIVE NAMES Kolbe, Adolph Wilhelm Hermann (full name)
BRIEF DESCRIPTION German chemist
DATE OF BIRTH September 27, 1818
PLACE OF BIRTH Elliehausen , today a district of Göttingen
DATE OF DEATH November 25, 1884
Place of death Leipzig