Bernhard Tollens

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Bernhard Tollens

Bernhard Christian Gottfried Tollens (born July 30, 1841 in Hamburg , † January 31, 1918 in Göttingen ) was a German agricultural chemist who dealt in particular with the chemistry and structure of sugar molecules .

Life path

Bernhard Tollens, son of a businessman, studied chemistry at the University of Göttingen from 1861 , received his doctorate there in 1864 and then worked first as a pharmacist, then as a chemist in Nuremberg, Bonn, Heidelberg and Paris. In 1870 he returned to Göttingen and got a job as an assistant in the chemical university laboratory headed by Friedrich Wöhler . In the same year he completed his habilitation in Göttingen with "Investigations on the allyl group". In 1873 Tollens was appointed associate professor and he was appointed director of the agricultural chemistry laboratory at the University of Göttingen. He worked here until 1911. From 1884 he was an assessor at the Göttingen Academy of Sciences .

Research services

The main scientific idea of ​​Tollens was to uncover fundamental connections between agriculture and chemistry. He chose carbohydrates as a research area. He developed a special form of the ring formula for sugar, which he derived from the Fischer projection and which is known as the Tollens formula . In organic chemistry textbooks, these Tollens formulas were later mostly replaced by the ring formulas according to Walter Norman Haworth . The Tollens reagent named after him (alkaline silver nitrate solution and ammonia) is used to detect sugars. See: Great test ! Another Tollens reagent is used to detect pentoses . It contains phloroglucinol and hydrochloric acid and produces a purple precipitate. With the naphthoresorcinol reagent developed by Tollens, glucuronates can be detected in urine .

Under the direction of Tollens, the agricultural chemistry laboratory at the University of Göttingen enjoyed international renown. Above all, students from the United States of America trained here to become agricultural chemists and often completed a full degree in agriculture. One of them was Charles Albert Browne, later known as an agricultural historian . The agricultural chemist Theodor Pfeiffer is one of the German Tollens students .

Tollens is the author of a successful book on the implementation of simple experiments in agricultural chemical laboratories. He also wrote a multi-edition manual on carbohydrates. Despite his special research focus on sugar chemistry, Tollens never lost sight of the practical application of his research results for agricultural practice. He gave numerous lectures in agricultural associations. He was way ahead of his time with his recommendation, first made in 1887, to the sugar manufacturers to pay for the beet delivered by the farmers not by weight but by sugar content.

Fonts

  • Paul Ehrenberg, Bernhard Baule (editor): Simple experiments for teaching chemistry. Compiled for agri-chemical laboratories. Berlin 1878, 2nd edition 1894, 3rd edition 1905, 4th, revised. u. Probably ed., ibid. 1920, 5th ed., ibid. 1927.
  • Short manual of carbohydrates. Breslau 1888; 2nd edition, ibid. 1895, 3rd edition, Leipzig 1914, 4th, newly edited. Ed. By Horst Elsner, ibid. 1935.

literature

  • Conrad von Seelhorst : "Bernhard Tollens †". In: Journal für Landwirtschaft, vol. 66, 1918, pp. 1–6 (with picture).
  • Paul Ehrenberg : "For Bernhard Tollens' one hundredth birthday". In: Yearbook of the Society for the History and Literature of Agriculture, vol. 40, 1941, pp. 38–42 (with picture).
  • Charles Albert Browne : "Bernhard Tollens (1841-1918) and some American students of his school of agricultural chemistry". In: Journal of Chemical Education , Vol. 19, 1942, pp. 253-259 (with picture).

Individual evidence

  1. ↑ Excerpt from the habilitation thesis, Annalen der Chemie und Pharmacie 156 , 129-174 (1870) , see also p. 174 , August 1870.
  2. ↑ Holger Krahnke: The members of the Academy of Sciences in Göttingen 1751-2001 (= Treatises of the Academy of Sciences in Göttingen, Philological-Historical Class. Volume 3, Vol. 246 = Treatises of the Academy of Sciences in Göttingen, Mathematical-Physical Class. Episode 3, vol. 50). Vandenhoeck & Ruprecht, Göttingen 2001, ISBN 3-525-82516-1 , p. 241.
personal data
SURNAME Great, Bernhard
ALTERNATIVE NAMES Tollens, Bernhard Christian Gottfried (full name)
BRIEF DESCRIPTION German agricultural chemist
DATE OF BIRTH July 30, 1841
PLACE OF BIRTH Hamburg
DATE OF DEATH January 31, 1918
Place of death Goettingen