Stanislao Cannizzaro

Stanislao Cannizzaro ( , , ; 13 July 1826 – 10 May 1910) was an Italian chemist. He is famous for the Cannizzaro reaction and for his influential role in the atomic-weight deliberations of the Karlsruhe Congress in 1860.

Biography Cannizzaro was born in Palermo in 1826. He entered the university there with the intention of making medicine his profession, but he soon turned to the study of chemistry. In 1845 and 1846, he acted as assistant to Raffaele Piria (1815–1865), known for his work on salicin, and who was then professor of chemistry at Pisa and subsequently occupied the same position at Turin.

During the Sicilian revolution of independence of 1848, Cannizzaro served as an artillery officer at Messina and was also chosen deputy for Francavilla in the Sicilian parliament; and, after the fall of Messina in September 1848, he was stationed at Taormina. On the collapse of the insurgents, Cannizzaro escaped to Marseille in May 1849, and, after visiting various French towns, reached Paris in October. There he gained an introduction to Michel Eugène Chevreul's laboratory, and in conjunction with F.S. Cloez (1817–1883) made his first contribution to chemical research, in 1851, when they prepared cyanamide by the action of ammonia on cyanogen chloride in ethereal solution. In the same year, Cannizzaro accepted an appointment at the National College of Alessandria, Piedmont as professor of physical chemistry. In Alessandria, he discovered that aromatic aldehydes are decomposed by an alcoholic solution of potassium hydroxide into a mixture of the corresponding acid and alcohol. For example, benzaldehyde decomposes into benzoic acid and benzyl alcohol, the Cannizzaro reaction. Cannizzaro showed how the atomic weights of elements contained in volatile compounds can be deduced from the molecular weights of those compounds, and how the atomic weights of elements of whose compounds the vapour densities are unknown can be determined from a knowledge of their specific heats. For these achievements, of fundamental importance to atomic theory, he was awarded the Copley Medal by the Royal Society in 1891. of which he was vice-president, and as a member of the Council of Public Instruction and in other ways he rendered important services to the cause of scientific education in Italy. He was awarded honorary membership of the Manchester Literary and Philosophical Society in 1888 in the light of this work.

Cannizzaro crater on the Moon was named after him in 1970.

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