Otto Wallach

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Otto Wallach

Otto Wallach (born March 27, 1847 in Königsberg i. Pr. , † February 26, 1931 in Göttingen ) was a German chemist and Nobel Prize winner . Wallach was an organic chemist and has discovered several reactions for building heterocyclic compounds and dyes. Wallach did fundamental work in terpene chemistry for the structure elucidation and the synthesis of this class of substances.

biography

Otto Wallach's father came from a Jewish family and converted to Lutheranism . He was an administrative officer and worked in the rank of senior government councilor in East Prussia . The mother, Otillie b. Thoma, came from Franche-Comté . In 1853 his father became director of the Chamber of Accounts in Potsdam and moved into a house at the Nauener Tor in Potsdam. From 1856 Otto Wallach attended a grammar school in Potsdam with Latin and Greek lessons and passed his Abitur on March 30, 1867 .

Education

He began his chemistry studies at the Georg-August-Universität Göttingen with Friedrich Wöhler and continued it in Berlin with August Wilhelm von Hofmann . There he also learned autodidactic languages: English, Italian, Spanish. He soon returned to Göttingen, where he did his doctorate on new isomeric compounds derived from toluene in 1869 with Hans Huebner .

From 1870 he became an employee of August Kekulé at the Rheinische Friedrich-Wilhelms-Universität Bonn and served in the Franco-Prussian War in 1870/1871 as an assistant to the Red Cross. In his memoirs he described the outbreak of war in Bonn. In 1871 he went to Agfa in Berlin, where he worked in chloral production.

Private lecturer and professor in Bonn

Wallach in the summer semester of 1872

In April 1872 Wallach got a job in Bonn at Kekulé in an internship for organic chemistry (alongside Ludwig Claisen , Wilhelm Koenigs, Walter Spring) with the prospect of a later habilitation . There he found a conversion of chloral to dichloroacetic acid or dichloroacetic acid ester under the catalytic influence of cyanide ions. He expanded this work into a habilitation thesis and became a private lecturer on February 4, 1873 , and in early 1876 he was given a full professorship . In Bonn, Wallach soon gave lectures on analytical chemistry, organic chemistry, theoretical chemistry and the history of chemical theories, so that Kekulé was very positive about Wallach. From 1879 Wallach taught pharmacy . From 1884 he included the essential oils - the terpenes - in his research.

Professor in Göttingen

From 1889 to 1915 Wallach was director of the Chemical Institute in Göttingen. There he organized the expansion of the institute and the realignment of the course (including the examination regulations). a. the dissociation theory took up and physical chemistry gave more space. The number of students doing internships rose from 67 to 260 (1914). Wallach was busy hiring new employees for the training: Arthur Kötz (organic synthesis), Julius Meyer (pulegenic acid), Wilhelm Biltz (terpene chemistry and inorganic chemistry), Albert Hesse (terpene chemistry), Karl Arthur Scheunert, Walther Borsche (amide , Imidchloride), Johannes Sielisch, Heinrich Wienhaus , Carl Mannich .

The establishment of the physical-chemical institute in Göttingen under the direction of Walther Nernst was initiated by Ministerialrat Friedrich Althoff . Gustav Tammann , later Richard Zsigmondy, was appointed head of the Inorganics Institute . Ferdinand Fischer was given his own institute for chemical technology. In addition to Berlin and Munich, Wallach's influence made Göttingen the most important training facility for chemists.

At Wallach in Göttingen, 219 doctoral students received their doctorates . These included well-known scientists such as Hans Heinrich Schlubach (later Professor in Hamburg), Ernst Schmitz (Professor of Physiology in Breslau), Arthur Binz (Secretary General of the German Chemical Society), Walter Norman Haworth (Professor of Sugar Chemistry and Nobel Prize Winner), Frederick Challenger (Professor for chemistry in Leeds), Julius Salkind (professor in Leningrad), Edward Kremers (professor for pharmacy in Madison, USA), Stefan Moycho and Franz Zienkowski.

Otto Wallach's grave at the Göttingen city cemetery

In 1909 the work Terpenes und Camphor von Wallach was published. In 1909 he was also elected President of the German Chemical Society.

Wallach learned from the newspaper in 1910 that he had been awarded the Nobel Prize in Chemistry . In 1912 Wallach became an honorary member of the Belgian Chemical Society. In November 1912 Wallach received the Davy Medal of the British Royal Society , which he was denied again in the First World War. Wallach was scheduled to leave the institute on July 31, 1914, one day before the outbreak of war. However, he continued his office until October 1, 1915.

Wallach suffered a stroke in September 1930 , a second followed in February 1931. He died on February 26, 1931 in Göttingen. His grave is located in the Göttingen city cemetery, where, in addition to himself, Max Born , Otto Hahn , Walther Nernst , Max von Laue , Max Planck , Adolf Windaus and Richard Zsigmondy are also buried as Nobel Prize winners.

Scientific achievements

The habilitation thesis referred to a very mild oxidation of aldehyde groups (e.g. in chloral ) with catalytic amounts of cyanide ions to form carboxylic acids or carboxylic acid esters. This very mild oxidation is still used in a slightly modified form (Corey oxidation) for very sensitive allyl alcohols in natural product syntheses. If manganese dioxide is added, the carboxylic acid or carboxylic acid ester can also be produced directly from unsaturated alcohols.

During the action of hydrogen sulfide on cyanide, Wallach discovered chrysean, a compound with a thiazole ring to which an amino and a thio-carbamide group are linked.

Amide chlorides and imide chlorides can be produced from acid amides after treatment with phosphorus pentachloride. Wallach discovered the amidines as a group of substances by converting imide chlorides with ammonia or amines. In this way, derivatives of imidazole could be produced from the amides of oxalic acid .

In the further investigation he was also able to produce thiamides, which could easily be alkylated on sulfur, so that thioesters or thiols can easily be produced.

Another area was the discovery of important groups of dyes, the disazo and trisazo compounds, which could be prepared from azoxybenzene and isomerization. As a result of this discovery, Agfa was soon able to bring the dye resorcinol brown onto the market. The working group then also developed the monoacetylation of diamines , so that only one amino group was diazotized.

Terpenes

Wallach's most important achievements were in the field of terpene chemistry. He began with this work from 1884. Wallach wrote 129 longer articles on terpene chemistry for Liebig's annals.

Since no appropriate spectroscopic methods were known for structure determination of organic compounds in earlier times, the constitutional formulas needed based on elemental analysis , molecular refraction , characteristics and behavior, degradation reactions and synthesis are reviewed. The correct classification into substance classes was essential for this work. Wallach also used the boiling points to derive groups of substances from terpenes. The most important goal was initially to determine the terpene groups with the empirical formula C 10 H 16 .

In 1887, Wallach derived a bicyclic structure for pinene (also the name for this terpene), which almost corresponded to the actual structure of pinene. As a result, many other terpenes could be separated and classified using crystallization methods (nitrosyl chloride, bromine attachment).

Wallach already suspected in 1885 that terpenes must be built up from a basic building block, isoprene. He did important educational work to determine the structure of pinene , limonene , cineole , dipentene , terpineol , pulegon , pinocarvone, cadinene and caryophyllene .

Rearrangement reactions such as from terpinolene to phellandren , terpinene were also investigated by him. He investigated the conversion of a six-membered ring (Pulegon) into a five-membered ring (Pulegen, Pulegenic acid) when pulegone was treated with bromine and the conversion when cyclohexanone was treated with bromine to cyclopentanone .

Ring expansion reactions were also examined by Wallach and his colleague H. Schrader. The work on the conversion of carvone to eucarvone and the conversion of cyclohexanol into cycloheptanol using a Reformatzky-Saytzeff reaction were important.

When Wallach started working on essential vegetable oils , the ingredients in each oil were named differently. At first he was able to prove that the connections were often identical. By addition of hydrogen halides succeeded gelding finally elucidate their structures. The subsequent industrial development of synthetic fragrances led to the collapse of the classic fragrance monopoly. The new possibilities for analysis allowed quality standards in the perfume industry for the first time .

Wallach established the biogenetic isoprene rule in 1887 (see terpenes ). The Leuckart-Wallach reaction is named after him and Rudolf Leuckart .

Honors

In memory of Otto Wallach, the company Dragoco Gerberding & Co. AG in Holzminden set up the Otto Wallach Fund in 1964 on the occasion of the 70th birthday of its founder, CW Gerberding, at the Gesellschaft Deutscher Chemiker (GDCh). From 1966 to 2002, the GDCh awarded the Otto Wallach plaque, endowed with a monetary prize, to researchers from European countries for their special achievements in the field of essential oils, terpenes and polyterpenes or biochemical attractants and deterrents.

The Faculty of Chemistry at the Georg August University of Göttingen also honors particularly outstanding achievements with the Otto Wallach Prize .

The lunar crater Wallach was named after him in 1979.

Works

literature

Individual evidence

  1. ^ Mathias Christmann: Otto Wallach: Founder of terpene chemistry and Nobel Prize winner 1910 . In: Angewandte Chemie . tape 122 , no. 50 , December 10, 2010, p. 9775–9781 , doi : 10.1002 / anie.201003155 ( wiley.com [accessed January 31, 2020]).
  2. ^ Frank Northen Magill: The Nobel Prize winners: Chemistry , Vol. 1: 1901-1937 . Salem Press, Pasadena 1990, ISBN 0-89356-562-8 .
  3. ↑ Otto Wallach: About the action of potassium cyanide on chloral, a new way of representing dichloroacetic acid . In: Ber. German Chem. Ges. 6 , 114-119 (1873). Digitized on Gallica .
  4. ↑ Elias J. Corey, Norman W. Gilman, BE Ganem: New methods for the oxidation of aldehydes to carboxylic acids and esters . In: Journal of the American Chemical Society , 90 : 5616 (1968).
  5. ↑ Otto Wallach: About a new sulfur-containing derivative of hydrogen cyanide . In: Ber. German Chem. Ges. 7 , 902-904 (1874). Digitized on Gallica .
  6. ^ O. Wallach and Arthur Grossmann: On the knowledge of the acid imide chlorides and amidines . In: Ber. German Chem. Ges. 11 , 753-755 (1878). Digitized on Gallica .
  7. ^ O. Wallach: On the knowledge of organic thio compounds . In: Ber. German Chem. Ges. 11 , 1590-1596 (1878). Digitized on Gallica .
  8. ↑ O. Wallach: The history of the azo dyes . In: Ber. German Chem. Ges. 15 , 22-29 (1882). Digitized on Gallica .
  9. ↑ Otto Wallach, Everhard Weber: On the knowledge of the terpenes and the essential oils . In: Liebigs Annalen der Chemie , Vol. 239 (1887), p. 1.
  10. ↑ Otto Wallach: To the knowledge of the terpenes and essential oils . In: Liebigs Annalen der Chemie , Vol. 227 (1885), p. 277.
  11. ↑ Otto Wallach, Carl Ohligmacher: To the knowledge of the terpenes and the essential oils. Observations in the Carvone Series. III: conversion products of caravan tribromide . In: Liebigs Annalen der Chemie , Vol. 305 (1899), p. 223.
  12. ↑ Otto Wallach: To the knowledge of the terpenes and essential oils. 85. Treatise: On the behavior of the nitrites of primary bases and on ring expansion of carbocyclic systems . In: Liebigs Annalen der Chemie , Vol. 353 (1907), p. 318.
  13. ↑ Member entry of Otto Wallach at the German Academy of Natural Scientists Leopoldina , accessed on October 12, 2012.

Web links

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personal data
SURNAME Wallach, Otto
BRIEF DESCRIPTION German chemist, Nobel Prize in Chemistry 1910
DATE OF BIRTH March 27, 1847
PLACE OF BIRTH Koenigsberg
DATE OF DEATH February 26, 1931
Place of death Goettingen