Marcellin Berthelot (1827-1907): The Chemist Who Made Chemistry a Science of Synthesis

Introduction

Pierre Eugene Marcellin Berthelot was a French chemist, historian of science and politician. He is remembered for the synthesis of organic compounds from simple elements, which struck a blow against vitalism, for his thermochemical measurements and the bomb calorimeter, and for his long public career. His legacy in one line: he showed that the chemistry of life follows the same laws as the chemistry of minerals.

Early Life and Family

Berthelot was born on 25 October 1827 in Paris. His father was a doctor, and the boy grew up in a family that valued learning and public service. He lived in the Paris of the 1830s and 1840s, a city of political change, and as a young man he took part in the republican debates of the time. He studied at the Lycee Henri IV in Paris and did well in history and philosophy as well as in the sciences, which later made him a writer of books outside chemistry.

Education and Mentors

After school he studied the sciences and medicine, but turned away from a medical career to concentrate on chemistry. In 1851 he became a preparator (assistant) to Antoine Jerome Balard at the College de France, and Balard, the discoverer of bromine, supported him. His doctoral thesis, on the synthesis of fats from glycerol, was presented in 1854. He was not formally a student of a famous chemist for long; he taught himself much and learned from Balard and the circle of the College de France.

Career Timeline

Major Scientific Contributions

• Total synthesis: Formic acid, methane, ethanol, acetylene, benzene and fats were prepared in the laboratory. See our discovery post for equations.
• Chemical equilibrium: Study of the ester equilibrium with Pean de Saint-Gilles, giving a clear example of reversible reactions.
• Thermochemistry: Invention of the bomb calorimeter and measurement of heats of reaction. He published a major work, "Essai de mecanique chimique fondee sur la thermochimie" (1879).
• Explosives: He studied the speed of explosion waves in gases and the behaviour of explosives, work of use to the French state.
• History of chemistry: He studied ancient texts on alchemy, published volumes on the origins of alchemy, and edited Greek and Syriac alchemical works.
• Agricultural chemistry: Studies on nitrogen fixation by soil, which anticipated later work on nitrogen-fixing bacteria.

Awards, Honours and Nobel Prize

Berthelot was elected to the Academie des Sciences in 1863 and became its permanent secretary in 1889. He was elected to the Academie francaise in 1900, held the rank of Grand Cross of the Legion of Honour, and sat as a senator for life. He was twice a minister. He did not receive a Nobel Prize.

Personality, Struggles and Lesser-Known Facts

• He opposed the atomic theory for many years and preferred to use equivalents, even after most chemists had accepted atoms. He felt that atoms were not proved by direct experiment. This was a long and public argument with Wurtz and others.
• He and Louis Pasteur held different views on fermentation. Berthelot argued that fermentation is caused by soluble chemical agents (ferments), and after his death, the work of Eduard Buchner on cell-free fermentation in 1897 supported this idea in part.
• During the siege of Paris in 1870-1871 he served on a scientific committee for the defence of the city, working on explosives and arms.
• He married Sophie Niaudet in 1861, and the couple were very close. When Sophie died on 12 March 1907, he is said to have been so affected that he died only a few days later, on 18 March.
• Both were buried together in the Pantheon in Paris, a place of honour for great French citizens. Their burial there was ordered as a national honour.
• He was a strong supporter of science education and of secular schools.

Legacy and Influence on Modern Chemistry

Berthelot made synthesis a core activity of organic chemistry, a line that leads to Fischer, Robinson, Woodward and modern drug synthesis. His thermochemical tables and methods created the field of calorimetry, and the bomb calorimeter remains a standard instrument. His studies of the esterification equilibrium helped students for generations to learn the concept of chemical equilibrium. In the history of chemistry, his work on alchemy created a bridge between the old and new science.

Lessons for Students

• Test the limits of a doctrine. Berthelot tried to make "vital" compounds in a flask, and succeeded.
• Measure carefully. His heats of reaction opened a new field.
• Be open to revising your own views. His resistance to atoms is a reminder that even great scientists can be wrong.
• Serve beyond the laboratory. He used his position to support education and public life.

FAQ

What is Berthelot best known for?

For the synthesis of many organic compounds from simple substances, including acetylene from carbon and hydrogen, and for founding thermochemistry.

What is the Berthelot-Thomsen principle?

It states that chemical reactions tend to go in the direction that releases the most heat. It is an approximation, as free energy decides spontaneity.

Where is Berthelot buried?

In the Pantheon in Paris, together with his wife Sophie, who died a few days before him.

Why did Berthelot oppose atoms?

He believed that atoms had not been shown by direct experiment, and he preferred to work with equivalents and measurable quantities such as heat.

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