Christian Friedrich Schönbein and the Ozone

Christian Friedrich Schönbein (1799 - 1868)

Christian Friedrich Schönbein (1799 – 1868)

On October 18, 1799, German-Swiss chemist Christian Friedrich Schönbein was born. Schönbein is best known for inventing the fuel cell (1838) and his discoveries of guncotton (nitrocellulose) and ozone.

Christian Friedrich Schönbein – Early Years

Christian Friedrich Schönbein came from a pietistic family, his father was a dyer, postman and bookkeeper. In 1812, after completing elementary school, he was apprenticed at a pharmaceutical factory in Böblingen and was adviced to begin studying at the university. Schönbein enrolled at the University of Erlangen in 1820 were he got to know Justus Liebig Friedrich Schelling, who later helped Schönbein to finance his studies. Schönbein started his teaching activities in chemistry, physics and mineralology near Rudolstadt before going to England and later Paris. In France, the scientist was educated for instance by Joseph Louis Gay-Lussac,[4Louis Jacques Thénard, and André-Marie Ampère.[5] At the age of 29, Schönbein was appointed professor without title at the University of Basel where he earned his honorary doctor’s degree and was appointed professor of chemistry in 1829. It is believed that during his years in Basel, At the time of the separation of the Basel cantons, he took the side of the city in order to ensure the continued existence of the university. To this end, he volunteered for the Academic Free Corps, with which he served for three weeks. This stand for the city earned him a lot of sympathy. In 1835 he was also granted citizenship of the city of Basel.

Research Work on Fuel Cells

In Basel, he first worked on isomerism and chemical passivity (1835). Brief immersion of iron in nitric acid made the iron passive. In 1838, Schönbein created a simple fuel cell by surrounding two platinum wires in hydrochloric acid with hydrogen and oxygen, respectively, and noticing an electrical voltage between the wires. A year later, he published these results.[6]

The Discovery of Ozone

While doing experiments on the electrolysis of water at the University of Basel, Christian Friedrich Schönbein first began to notice a distinctive odor in his lab. The smell gave Schönbein the clue to the presence of a new product from his experiments. Because of the pronounced smell, Schönbein coined the term “ozone” for the new gas, from the Greek word “ozein“, meaning “to smell“. Schönbein described his discoveries in publications in 1840. He later found that the smell of ozone was similar to that produced by the slow oxidation of white phosphorus. The ozone smell Schönbein detected is the same as that occurring in the vicinity of a thunderstorm, an odor that indicates the presence of ozone in the atmosphere.[11]

Healthy Ozone ?

During the second half of the nineteenth century, ozone was considered a healthy component of the environment by naturalists and health-seekers. The Beaumont, California, had as its official slogan “Beaumont: Zone of Ozone,” as evidenced on postcards and Chamber of Commerce letterhead. Naturalists working outdoors often considered the higher elevations beneficial because of their ozone content. “There is quite a different atmosphere with enough ozone to sustain the necessary energy to work,” wrote naturalist Henry Henshaw, working in Hawaii. Seaside air was considered to be healthy because of its “ozonecontent but the smell giving rise to this belief is in fact that of halogenated seaweed metabolites.

Research on Gun Cotton

While investigating questions about the molecular nature of ozone, Schönbein believed that it was related to nitric acid (this acid also produces a peculiar odor). He now examined several substances, including sulfur, sugar, paper and cotton, under the influence of nitric acid. By reacting nitric acid with cotton, he produced an interesting substance, gun cotton (1846). He had discovered this as early as 1832 in an accident (he mopped up nitric and sulfuric acid with a cotton apron and hung it in front of a fireplace to dry, creating a pilot flame). Schönbein investigated this substance as an explosive to replace gunpowder. Although he and his partners were striving to produce it on a large scale, spontaneous explosions seemed to make it completely impossible at the time. It was not until 1884 that Paul Vieille tamed guncotton into a successful progressive smokeless gunpowder called Poudre B. Later on, in 1891, James Dewar [12] and Frederick Augustus Abel [13] also managed to transform gelatinized guncotton into a safe mixture, called cordite because it could be extruded into long thin cords before being dried.

Further Research

Schönbein’s areas of research were wide-ranging: for example, he coined the term geochemistry in 1838, developed the first test for detecting blood from hydrogen peroxide in 1863, and dealt with biological issues, such as red blood cells, urine and fungi. He was particularly interested in the preservation of foodstuffs (meat, vegetables) against biological spoilage. Schönbein was also concerned with the nitrogenous combustion products of air and assumed that the inert atmospheric nitrogen was converted by such oxidation processes into ammonia-containing products in the plant. Schönbein now investigated the effect of nitrate and nitrites on plants.

Later Years

As a long-standing member of the municipal lighting commission and as co-founder and head of the museum association for the acquisition of scientific and art collections, he rendered outstanding services to the welfare of the city of Basel, which granted him honorary citizenship in 1840. He also worked to improve the hygienic conditions in Basel by creating a sewer system. Among other things, he founded the Basler Liedertafel and the Basler Hebelstiftung, of which he was president from 1860 to 1868. In 1848 he was elected for the conservatives to the cantonal parliament, the Grand Council, of which he was a member until his death. There he caused a stir when he advocated a separation of church and state, but this was rejected. From 1851 he was also a member of the Basel City Council. In 1868 he took a cure for gout in Bad Wildbad. During a stay in Baden-Baden he died on August 29, 1868.

A brief introduction to the basic concepts of Ozone, [15]

References and Further Reading:

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