Hermann Kolbe

Adolph Wilhelm Hermann Kolbe ( born September 27, 1818 in Hausen Ellie, now a city district of Göttingen, † November 25, 1884 in Leipzig ) was a German chemist. He has discovered the electrolysis of carboxylic acids linking possibility of alkyl radicals of acids and presented for the first time here salicylic acid from phenolate and carbon dioxide.

Curriculum vitae

Kolbe was the eldest of 15 children of the pastor Karl Kolbe and his wife Auguste born Hempel. He attended the grammar school in 1831 in Göttingen. After studying chemistry in 1838, Friedrich Wöhler in Göttingen he became in 1842 assistant to Robert Wilhelm Bunsen at the University of Marburg. In the autumn of 1843 he was awarded with the work Concerning the products of the action of chlorine on carbon disulphide the doctoral degree ( Dr. rer. Nat. ). From 1845 to 1847 Kolbe was an assistant with Lyon Playfair at the University of London, where he became friends with Edward Frankland. Kolbe and Frankland in London in the representation of carboxylic acids from nitriles. The electrolysis of carboxylic acids with the formation of carbon dioxide and the dimerized alkanes fell in this period (1847 Kolbe also worked in Marburg with Bunsen ).

In the autumn of 1847 Kolbe went to edit the Handucheswörterbuches chemistry to Brunswick due to a range of publishing Fr Vieweg & Sohn.

1851 Kolbe followed the call of the chair of chemistry at the University of Marburg as the successor of Robert Bunsen. 1853 Kolbe married Charlotte of Bardeleben. In 1865 he became a full professor at the University of Leipzig.

Scientific work

As Kolbe began to study chemistry, organic chemistry as a science was quite unknown. From elemental analyzes conducted chemist from the relative levels of carbon, hydrogen and oxygen in an organic compound, was completely unknown at this time, the structure and the type of the atomic exchange of molecules in a chemical reaction. In this phase, many transformations have been studied to conclude with the aim of change in elemental composition to discover a certain order and on the chemical constitution and the reaction behavior of compounds.

Once in organic chemistry, the dualistic radical theory was shaken ( with a positive and a negative area in each inorganic and organic particles ) by Jöns Jacob Berzelius by the discovery of substitution by Jean Baptiste Dumas of a unitary theory of types, there were two camps in the organic chemistry. The one bearing ( Charles Gerhardt, Auguste Laurent ) trying new ideas to expand the type theory, the other camp tried to reform through mental auxiliary constructs the dualistic theory of Berzelius. 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 studied for his dissertation work (1842 - 1843), the conversion of carbon disulfide with chlorine. He received in addition to the organic chlorine compounds, a crystalline substance trichloromethanesulfonic. Its creation was Kolbe from the dualistic theory derived. By treatment with sodium amalgam all chlorine atoms were replaced by hydrogen atoms, so that was formed methane. Kolbe found out later that tetrachloroethene (generated from carbon tetrachloride in passage through a glowing tube ) transformed in the sunlight in the presence of water and chlorine to trichloroacetic acid. The trichloroacetic acid could be converted with sodium amalgam in acetic acid. In his article, the first word has been used in the field of synthetic organic chemistry. Kolbe hoped at the time that using the organic chemistry of simple substances such as acetic acid complex substances such as sugar could be produced in the future. In his work, a new carbon -carbon bond has been attached, the chloro substituents on the carbons have been replaced by hydrogen and oxygen.

Kolbe visited his friend Edward Frankland in London. With Frankland a new synthesis of carboxylic acids has been developed. They synthesized from alkyl cyanides (acetonitrile, ethylnitrile of Dumas and Théophile -Jules Pelouze first synthesized ) by saponification of the corresponding carboxylic acids. Kolbe and Frankland now assumed that the cyanogen compounds are paired carboxylic acids with radicals. Hydrogen cyanide matched their view oxalic acid ( carboxyl group), acetonitrile, acetic acid. Kolbe wanted to know if can cleave the methyl radical from the acetic acid, if have the potential to produce a pure radical now.

To achieve this, it electrolyzed acetic acid (see electrolysis). It was created at the positive pole is actually a substance with the chemical composition of a methyl radical and carbon dioxide. However, the molecular weight of the methyl radical was higher than expected, there was formed ethane. Kolbe was now certain that the acetic acid from two radical pairs is: the carbonic acid and the methyl radical. Later he electrolyzed also higher alkanoic acids and could prove even with these carbon dioxide formation and alkane formation. Due to the electrochemical experiments Kolbe again supported the dualistic theory of Berzelius. Following the ideas for saturation capacities of the elements by Frankland Kolbe revised the radical theory

He saw in this work to all organic materials as derivatives of carbonic acid, have been caused by substitution processes. Kolbe changed the formal type theory of Gerhardt to a real type theory, he called Gerhardt's type theory as unscientific formula gimmick. Kolbe rejected the thesis of Gerhardt that a chemical compound can have several constitutional formulas. He predicted from his theory, the possibility of the existence of secondary and tertiary alcohols ..

These alcohols were a few years later found by Alexander Butlerov 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 development of a simple synthesis of salicylic acid was (acetylsalicylic acid (aspirin) is a derivative of salicylic acid ) is particularly significant. Salicylic acid was prepared by him of phenol in the presence of carbon dioxide and sodium. Complete elucidation of the formation of salicylic acid, however, brought only Rudolf Schmitt.

He became a partner founded by Friedrich von Heyden 1874 Salicylsäurefabrik Dr. F. von Heyden, the first drug synthesis operation in Radebeul world on an industrial scale due to the transfer of its Kolbe synthesis. His son Carl Kolbe, also a chemist, took over in 1884 until the line and 1885 the factory from its founder. 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 Technical University of Hanover. And his grandson Ferdinand Hermann, Krauss became a professor of chemistry.

Teaching and university

Kolbe has written a comprehensive textbook of organic chemistry ( 1854-1865 ). Furthermore, a concise textbook for inorganic and organic chemistry.

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

Between 1847 to 1851 he edited the manual dictionary of pure and applied chemistry in Braunschweig at Vieweg Verlag.

According to his plans, the chemical institute in Leipzig was built in 1868.

As a teacher, he turned to a learning method that careful observation and reflection promoted the students.

Among his students and colleagues in Leipzig were Ernst Otto Beckmann, Alexander Mikhailovich Zaitsev and Theodor Curtius.

Awards

Kolbe was nominated for his work to the Privy Councilor. In 1877, he received in Tübingen Dr. med h c.

These Kolbe was a member or honorary member of several scientific institutions, the Royal Saxon Society of Sciences, Kazan and Kiev universities and the Royal Society of Edinburgh.

Kolbe was in 1872 Knight of the Bavarian Maximilian Order for Science and Art, and received in 1884 by the Royal Society Davy Medal.

Since 1 October 2012, the former Salicylsäurefabrik and later Chemische Fabrik Dr. F. von Heyden is one of the historical sites of Chemistry, awarded by the German Chemical Society ( German Chemical Society ) at a ceremony with a plaque at the main building in Radebeul. This is reminiscent of the work of Jacob Friedrich von Heyden, Adolph Wilhelm Hermann Kolbe, Rudolf Wilhelm Schmitt, Bruno Richard Seifert and Richard Gustav Müller.

Works

• Short textbook of chemistry, Volume 1 Vieweg, Braunschweig second verb. Digitized edition 1884 edition of the University and State Library Dusseldorf