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August Wilhelm von Hofmann (8 April 1818 – 5 May 1892 [2]) was a German chemist who made considerable contributions to organic chemistry. His research on aniline helped lay the basis of the aniline-dye industry, and his research on coal tar laid the groundwork for his student Charles Mansfield's practical methods for extracting benzene and toluene and converting them into nitro compounds and ...
The Hofmann rearrangement (Hofmann degradation) is the organic reaction of a primary amide to a primary amine with one less carbon atom. [ 1 ][ 2 ][ 3 ] The reaction involves oxidation of the nitrogen followed by rearrangement of the carbonyl and nitrogen to give an isocyanate intermediate. The reaction can form a wide range of products ...
In 1865, German chemist August Wilhelm von Hofmann was the first to make stick-and-ball molecular models, which he used in lecture at the Royal Institution of Great Britain, such as methane shown below: Hofmann's 1865 stick-and-ball model of methane CH 4.
A Hofmann voltameter is an apparatus for electrolysing water, invented by August Wilhelm von Hofmann (1818–1892) [1] in 1866. It consists of three joined upright cylinders, usually glass. The inner cylinder is open at the top to allow addition of water which contains a low concentration of a compound such as sulfuric acid to improve ...
August Wilhelm von Hofmann is credited with the first physical molecular model around 1860. [3] Note how the size of the carbon appears smaller than the hydrogen. The importance of stereochemistry was not then recognised and the model is essentially topological (it should be a 3-dimensional tetrahedron).
Hofmann–Martius rearrangement. The Hofmann–Martius rearrangement in organic chemistry is a rearrangement reaction converting an N-alkylated aniline to the corresponding ortho and / or para aryl -alkylated aniline. The reaction requires heat, and the catalyst is an acid like hydrochloric acid. [1][2]
William Henry Perkin. Sir William Henry Perkin FRS (12 March 1838 – 14 July 1907) [1] was a British chemist and entrepreneur best known for his serendipitous discovery of the first commercial synthetic organic dye, mauveine, made from aniline. Though he failed in trying to synthesise quinine for the treatment of malaria, he became successful ...
It is likely that the CPK colours were inspired by models in the nineteenth century. In 1865, August Wilhelm von Hofmann, in a talk at the Royal Institution in London, was using models made from croquet balls to illustrate valence, so he used the coloured balls available to him. (At the time, croquet was the most popular sport in England, so ...