Stanislao Cannizzaro
Encyclopedia
Stanislao Cannizzaro, FRS (July 13, 1826 – May 10, 1910) was an Italian
chemist
. He is remembered today largely for the Cannizzaro reaction
and for his influential role in the atomic-weight deliberations of the Karlsruhe Congress
in 1860.
. In 1841, 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
.
In the autumn of 1855, Cannizzaro became professor of chemistry at the University of Genoa
, and, after further professorships at Pisa and Naples
, he accepted the chair of inorganic and organic chemistry at Palermo. There, he spent ten years studying aromatic compounds and continuing to work on amine
s, until in 1871 when he was appointed to the chair of chemistry at the University of Rome
.
Apart from his work on organic chemistry, which includes also an investigation of santonin, Cannizzaro rendered great service to chemistry with his 1858 paper Sunto di un corso di Filosofia chimica, or Sketch of a course of chemical philosophy, in which he insisted on the distinction, previously hypothesized by Avogadro
, between atomic and molecular weights. 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.
In 1871, Cannizzaro's scientific eminence secured him admission to the Italian senate, 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 is best known for his contribution to the then-existing debate over atoms, molecules, and atomic weights. He championed Amedeo Avogadro's notion that equal volumes of gas at the same pressure and temperature held equal numbers of molecules or atoms, and the notion that equal volumes of gas could be used to calculate atomic weights. In so doing, Cannizzaro provided a new understanding of chemistry.
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
chemist
Chemist
A chemist is a scientist trained in the study of chemistry. Chemists study the composition of matter and its properties such as density and acidity. Chemists carefully describe the properties they study in terms of quantities, with detail on the level of molecules and their component atoms...
. He is remembered today largely for the Cannizzaro reaction
Cannizzaro reaction
The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction that involves the base-induced disproportionation of an aldehyde lacking a hydrogen atom in the alpha position...
and for his influential role in the atomic-weight deliberations of the Karlsruhe Congress
Karlsruhe Congress
The Karlsruhe Congress was an international meeting of chemists held in Karlsruhe, Germany from 3 to 5 September, 1860. It was the first international conference of chemistry worldwide.- The meeting :...
in 1860.
Biography
Cannizzaro was born in PalermoPalermo
Palermo is a city in Southern Italy, the capital of both the autonomous region of Sicily and the Province of Palermo. The city is noted for its history, culture, architecture and gastronomy, playing an important role throughout much of its existence; it is over 2,700 years old...
. In 1841, 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
Pisa
Pisa is a city in Tuscany, Central Italy, on the right bank of the mouth of the River Arno on the Tyrrhenian Sea. It is the capital city of the Province of Pisa...
and subsequently occupied the same position at Turin
Turin
Turin is a city and major business and cultural centre in northern Italy, capital of the Piedmont region, located mainly on the left bank of the Po River and surrounded by the Alpine arch. The population of the city proper is 909,193 while the population of the urban area is estimated by Eurostat...
.
During the Sicilian revolution of independence of 1848
Sicilian revolution of independence of 1848
The Sicilian revolution of independence of 1848 occurred in a year replete with revolutions and popular revolts. It commenced on 12 January 1848, and therefore was one of the first of the numerous revolutions to occur that year...
, Cannizzaro served as an artillery officer at Messina and was also chosen deputy for Francavilla
Francavilla
Francavilla can refer to:People*Pietro FrancavillaPlaces*Francavilla Angitola*Francavilla Fontana*Francavilla Bisio*Francavilla di Sicilia*Francavilla Marittima*Francavilla d'Ete*Francavilla in SinniOther*A.S.D. Francavilla Calcio...
in the Sicilian parliament; and, after the fall of Messina in September 1848, he was stationed at Taormina
Taormina
Taormina is a comune and small town on the east coast of the island of Sicily, Italy, in the Province of Messina, about midway between Messina and Catania. Taormina has been a very popular tourist destination since the 19th century...
. On the collapse of the insurgents, Cannizzaro escaped to Marseille
Marseille
Marseille , known in antiquity as Massalia , is the second largest city in France, after Paris, with a population of 852,395 within its administrative limits on a land area of . The urban area of Marseille extends beyond the city limits with a population of over 1,420,000 on an area of...
in May 1849, and, after visiting various French towns, reached Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...
in October. There he gained an introduction to Michel Eugène Chevreul
Michel Eugène Chevreul
Michel Eugène Chevreul was a French chemist whose work with fatty acids led to early applications in the fields of art and science. He is credited with the discovery of margaric acid and designing an early form of soap made from animal fats and salt...
's laboratory, and in conjunction with F.S. Cloez
F.S. Cloez
F.S. Cloez was a French chemist, who also authored as "S. Cloez", and is known for his pioneering role in analytical chemistry during the 19th century....
(1817 – 1883) made his first contribution to chemical research, in 1851, when they prepared cyanamide
Cyanamide
Cyanamide is an organic compound with the formula CN2H2. This white solid is widely used in agriculture and the production of pharmaceuticals and other organic compounds. It is also used as an alcohol deterrent drug in Canada, Europe and Japan. The molecule features a nitrile group attached to an...
by the action of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
on cyanogen chloride
Cyanogen chloride
Cyanogen chloride is an inorganic compound with the formula NCCl. This linear, triatomic pseudohalogen is an easily condensed colorless gas. More commonly encountered in the laboratory is the related compound cyanogen bromide, a room-temperature solid that is widely used in biochemical analysis and...
in ethereal solution. In the same year, Cannizzaro accepted an appointment at the National College of Alessandria
Alessandria
-Monuments:* The Citadel * The church of Santa Maria di Castello * The church of Santa Maria del Carmine * Palazzo Ghilini * Università del Piemonte Orientale-Museums:* The Marengo Battle Museum...
, Piedmont
Piedmont
Piedmont is one of the 20 regions of Italy. It has an area of 25,402 square kilometres and a population of about 4.4 million. The capital of Piedmont is Turin. The main local language is Piedmontese. Occitan is also spoken by a minority in the Occitan Valleys situated in the Provinces of...
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 reaction
The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction that involves the base-induced disproportionation of an aldehyde lacking a hydrogen atom in the alpha position...
.
In the autumn of 1855, Cannizzaro became professor of chemistry at the University of Genoa
University of Genoa
The University of Genoa is one of the largest universities in Italy.Located in Liguria on the Italian Riviera, the university was founded in 1471. It currently has about 40,000 students, 1,800 teaching and research staff and about 1,580 administrative staff.- Campus :The University of Genoa is...
, and, after further professorships at Pisa and Naples
Naples
Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...
, he accepted the chair of inorganic and organic chemistry at Palermo. There, he spent ten years studying aromatic compounds and continuing to work on amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
s, until in 1871 when he was appointed to the chair of chemistry at the University of Rome
University of Rome La Sapienza
The Sapienza University of Rome, officially Sapienza – Università di Roma, formerly known as Università degli studi di Roma "La Sapienza", is a coeducational, autonomous state university in Rome, Italy...
.
Apart from his work on organic chemistry, which includes also an investigation of santonin, Cannizzaro rendered great service to chemistry with his 1858 paper Sunto di un corso di Filosofia chimica, or Sketch of a course of chemical philosophy, in which he insisted on the distinction, previously hypothesized by Avogadro
Amedeo Avogadro
Lorenzo Romano Amedeo Carlo Avogadro di Quaregna e di Cerreto, Count of Quaregna and Cerreto was an Italian savant. He is most noted for his contributions to molecular theory, including what is known as Avogadro's law...
, between atomic and molecular weights. 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
Copley Medal
The Copley Medal is an award given by the Royal Society of London for "outstanding achievements in research in any branch of science, and alternates between the physical sciences and the biological sciences"...
by the Royal Society
Royal Society
The Royal Society of London for Improving Natural Knowledge, known simply as the Royal Society, is a learned society for science, and is possibly the oldest such society in existence. Founded in November 1660, it was granted a Royal Charter by King Charles II as the "Royal Society of London"...
in 1891.
In 1871, Cannizzaro's scientific eminence secured him admission to the Italian senate, 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 is best known for his contribution to the then-existing debate over atoms, molecules, and atomic weights. He championed Amedeo Avogadro's notion that equal volumes of gas at the same pressure and temperature held equal numbers of molecules or atoms, and the notion that equal volumes of gas could be used to calculate atomic weights. In so doing, Cannizzaro provided a new understanding of chemistry.
External links
- Sketch of a course of chemical philosophy by Cannizzaro (1858) - Edinburgh: Alembic Club Reprint No. 18 (1911). by Thomas Edward Thorpe in Essays in Historical Chemistry, London: Macmillan, pages 500 – 513 (also Nature, May 6, 1897).
- George B. Kauffman, (1996). Review of Lettere a Stanislao Cannizzaro 1868-1872; Stanislao Cannizzaro: Scritti di Storia Politica e Chimica; Corrispondenza Varia, a set of Cannizzaro's papers