Christian Friedrich Schönbein

Christian Friedrich Schönbein (October 18, 1799 – August 29, 1868) was a German-Swiss chemist who is most well-known for his discovery of guncotton.

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In 1838, he discovered the principle behind the fuel cell. He also discovered ozone, a form of oxygen, in 1839 during experiments he performed on the slow oxidation of white phosphorus and the electrolysis of water.

It was during these experiments at the University of Basel in Switzerland where Schönbein had been a professor since 1828, that he first began to notice a distinctive odour.

Ozone has a strong smell. It is this odour - especially occurring in the vicinity of a thunderstorm – that indicates the presence of ozone in the atmosphere. This gave Schönbein the clue to the presence of Ozone during his own experiments. Because of this strong smell, Schönbein coined the term ‘Ozone’ from the Greek word ‘ozein’, meaning ‘to smell’.

Schönbein described his discoveries in a letter entitled "Research on the nature of the odor in certain chemical reactions" presented to the Academies des Sciences in Paris in 1840.

Although his wife had forbidden him to do so, he occasionally experimented at home in the kitchen; one day in 1845, when his wife was away, he spilled a mixture of nitric acid and sulfuric acid. After using his wife's cotton apron to mop it up, he hung the apron over the stove to dry, only to find it spontaneously ignite and burn so quickly that it seemed to disappear. Schönbein had converted the cellulose of the apron into nitrocellulose; the nitro groups (added from the nitric acid) served as an internal source of oxygen, and when heated, the cellulose was completely oxidized, all at once.

Schönbein recognized the possibilities of the compound. Ordinary black gunpowder, which had reigned supreme in the battlefield for the past 500 years, exploded into thick smoke, blackening the gunners, fouling the cannon and small arms, and obscuring the battlefield. Nitrocellulose was a possible "smokeless powder", and from its potential as a propellant for artillery shells, it received the name guncotton.

Attempts to manufacture guncotton for military use failed at first because the factories had a tendency to blow up; it was not until 1891 that James Dewar and Frederick Augustus Abel managed to compound a safe mixture that included guncotton, called cordite because it could be pressed into long cords.

Further reading

• Brown GI. The Big Bang: A History of Explosives, Sutton Publishing; 1998 (ISBN 0750937920)