Hoffmann, August Wilhelm

Haber, Ludwig Fritz, 228 Haber, Paula, 65 Haber, Siegfried, 65 Hahn, Otto, 231 Hellriegel, Hermann, 14-16 Hessberger, Johannes, 75 Hildebrand, Georg F., 62 Hitler, Adolf, 224, 229-230 Hoffmann, August Wilhelm von, 66 Humholdt, Alexander von, 41... 

Hexamethylphosphoramide Hoffmann, Roald, 1180 Hoffmann-I.a Roche Co., vitamin C synthesis and, 773 von Hofmann. August Wilhelm, 933 Hofmann elimination reaction. 936-938... 

Formaldehyde is a colorless, flammable gas with a distinctive pungent odor. It is the simplest aldehyde, which is a class of organic compounds with the carbonyl group bonded to at least one hydrogen atom. Formaldehyde was described by August Wilhelm von Hoffmann (1818—1892) in 1867 after the Russian Aleksandr Butlerov (1828—1886) had inadvertently synthesized it in 1857. Formaldehyde readily dissolves in water to produce a solution called formalin, which is commonly marketed as a 37% solution. 

A classic story of this line of research was the discovery of a method for the manufacture of the dye now known as mauve by the English chemist Sir William Henry Perkin (1838-1907). In 1856, Perkin was an 18-year-old student of the great German chemist August Wilhelm von Hoffmann (1818-92), superintendent of the Royal College of... 

In the middle of the nineteenth century, the precocious William Henry Perkin (1838-1907) entered the Royal College of Chemistry at the age of 15 and soon became an assistant to its Director, Professor August Wilhelm Hofrnann. " By that time, coal tar had become an unwanted waste product and while commercial benzene and toluene had been obtained from coal tar by distillation, it was still considered a massive nuisance. Working in his home laboratory in London in 1856, young Perkin tried unsuccessfully to synthesize the dmg quinine but obtained instead dark tars. A modification, using the coal-tar component aniline, provided another dark substance that was found, again quite by accident, to be an excellent purple dye, that Perkin named mauve. Perkin left the university, much to Hoffmann s dismay, and built a factory to manufacture mauve financed by his father. Suddenly, a synthetic dye industry emerged and coal tar became a commodity rather than a waste product. 

Fig. 2 Historical apparatuses used to study the oxygen evolution reaction (OER) by Johann Wilhelm Ritter (a) [27] and August Wilhelm von Hoffmann (b) [28] as well as a Knallgasvoltameter (oxyhydrogen gas voltameter c) [29], in which the oxygen evolution reaction is employed to measure electric current. In all drawings, the ratio of 2 1 for hydrogen gas to oxygen gas can be seen clearly...

---