August Wilhelm von Hofmann

Infobox_Scientist
name = August Wilhelm von Hofmann


caption = August Wilhelm von Hofmann
birth_date = birth date|1818|4|8|mf=y
birth_place = Giessen, Germany
residence = Germany
nationality = German
death_date = death date and age|1892|5|5|1818|4|8|mf=y
death_place = Berlin, Germany
field = Chemist
work_institution = University of Bonn
Royal College of Chemistry
Berlin University
alma_mater = University of Göttingen
doctoral_advisor = Justus von Liebig
doctoral_students = Richard Abegg
Adolf Pinner
Fritz Haber
Karl Friedrich von Auwers
Rudolf Hugo Nietzki
Ferdinand Tiemann
Eugen Bamberger
known_for = Hofmann rearrangement
Hofmann elimination
Hofmann-Löffler reaction
prizes =
religion =
footnotes =

August Wilhelm von Hofmann (April 8, 1818 – May 5, 1892) was a German chemist.

Biography

Hofmann was born at Gießen, Grand Duchy of Hesse. Not intending originally to devote himself to physical science, he first took up the study of law and philology at Göttingen. But he then turned to chemistry, and studied under Justus von Liebig at University of Giessen. When, in 1845, a school of practical chemistry was started in London, under the style of the Royal College of Chemistry, Hofmann, largely through the influence of the Prince Consort, was appointed its first director. It was with some hesitation that he, then a Privatdozent at Bonn, accepted the position, which may well have seemed rather a precarious one; but the difficulty was removed by his appointment as extraordinary professor at Bonn, with leave of absence for two years, so that he could resume his career in Germany if his English one proved unsatisfactory. Fortunately the college was more or less successful, owing largely to his enthusiasm and energy, and many of the men who were trained there subsequently made their mark in chemical history. In 1864 he returned to Bonn, and in the succeeding year he was selected to succeed Eilhard Mitscherlich as professor of chemistry and director of the laboratory in Berlin University.

compounds while his researches on rosaniline, which he first prepared, formed the first of a series of investigations on coloring matter which only ended with quinoline red in 1887.

The Hofmann rearrangement and Hofmann elimination reaction bear his namesake. Hofmann was also the first to introduce molecular models into his public lectures around 1860, following the earlier (1855) suggestion by his colleague William Odling that carbon is tetravalent. This legacy is still remembered nowadays by continuing use of Hofmann's colour scheme: (carbon = black, hydrogen = white, nitrogen = blue, oxygen = red, chlorine = green, sulfur = yellow, as cited by W. D. Ollis, "Models and molecules", "Proceedings of the Royal Institution of Great Britain", (1972), 45, 1-31). The models look rather odd nowadays, primarily because Hofmann had them built so that the carbon was planar, and smaller in size than the hydrogen! (it was Loschmidt in 1861 who probably first appreciated the differing sizes of different atoms). It was not until 1874, when Jacobus Henricus van't Hoff and (independently) Joseph Achille Le Bel suggested carbon can be tetrahedral, that molecular models assumed their modern appearance.

William Henry Perkin was a student of his at the Royal College of Chemistry in London, when he discovered the first aniline dye, mauveine.

ee also

*Hofmann voltameter
*History of the molecule
*Timeline of hydrogen technologies

=References= Commons|August Wilhelm von Hofmann

*cite journal
title = The Contributions of A. W. Hofmann
author = Theodore A. Alston
journal = Anesthesia Analgesia
year = 2003
volume = 96
issue =
pages = 622–625
url = http://www.anesthesia-analgesia.org/cgi/content/abstract/96/2/622
doi = 10.1097/00000539-200302000-00058
pmid = 12538223

*cite journal
title = A. W. Hofmann and the Founding of the Royal College of Chemistry
author = John J. Beer
journal = Journal of Chemical Education
year = 1960
volume = 37
issue = 5
pages = 248 – 251

*cite journal
title = August Wilhelm Hofmann - Reigning Chemist-in-Chief
author = Christoph Meinel
journal = Angewandte Chemie International Edition in English
year = 1992
volume = 31
issue = 10
pages = 1265–1282
doi = 10.1002/anie.199212653

*cite journal
title = The origin of the coal-tar colour industry, and the contributions of Hofmann and his pupils
author = William Henry Perkin
journal = Journal Chemical Society Transaction
year = 1896
volume = 69
issue =
pages = 596
doi = 10.1039/CT8966900596

*cite journal
title = August Wilhelm Hofmann (1818–1892)
author = Anthony S. Travis
journal = Endeavour
year = 1992
volume = 16
issue = 2
pages = 59–65
doi = 10.1016/0160-9327(92)90003-8 2

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*1911

Persondata
NAME= Hofmann, August Wilhelm von
ALTERNATIVE NAMES=
SHORT DESCRIPTION= German Chemist
DATE OF BIRTH= April 8, 1818
PLACE OF BIRTH= Giessen, Germany
DATE OF DEATH= May 5, 1892
PLACE OF DEATH= Berlin, Germany