35 No. 5
|Paul Sabatier, Dean of the Faculty of Sciences
The year 2012 was the centenary of the Nobel Prize in chemistry awarded to Victor Grignard and Paul Sabatier. Throughout the year, many lectures and events were held in France to celebrate this anniversary and the contributions of both scientists. To begin the year, the French Ministry of Culture published a book commemorating the French successes of 1912. On 10 April 2012, the French Academy of Sciences celebrated Sabatier and Grignard in Paris.
However, it was Sabatier, whose discovery in the field of catalysis had a profound impact on industrial development, who garnered the most attention during the centennial. The center of the tributes to Sabatier’s life and work was the Scientific Toulouse University (Paul Sabatier University), which housed his laboratory and where he worked for 47 years.
In 2012, two international symposia were held in Toulouse that honored Sabatier: the 18th International Symposium on Homogeneous Catalysis (July) and the Power Plant and Power Systems Control Conference (September). Both meetings began with a lecture on the crucial contributions of Paul Sabatier to the field of catalysis.
On 12 October 2012, a museum dedicated to Paul Sabatier was inaugurated in the library of the Ecole Nationale Supérieure des Industries et Arts Chimiques de Toulouse. Sabatier’s grandson attended the ceremony. Over the following three months, lectures and movies about Sabatier were offered to the public.
During November and December 2012, four events for the general public were organized by the Paul Sabatier University in Toulouse: three lectures on the regional impact of the life and work of Paul Sabatier, the history of catalysis, and the importance of nanotechnologies in the new catalysis; and a round table conference on the role of catalysis in every day life.
Paul Sabatier was born on 5 November 1854 in Carcassonne, a small medieval town with an impressive fortress, which is 90 km from Toulouse in southwest France. He attended primary school in Carcassonne before moving to the “Lycée” in Toulouse in 1868. He finished his secondary studies at Sainte Marie’s school, a catholic high school, under the supervision of Jesuit priests.
|Program from the 12 October 2012 opening of a museum dedicated to Paul Sabatier in the library of the Ecole Nationale Supérieure des Industries et Arts Chimiques de Toulouse.
At 18, with a bachelor of sciences and a bachelor of humanities, Paul Sabatier began his preparatory studies for admission to a “grande école” at Sainte Geneviève school in Versailles. At 20, he had gained admission to both the “Ecole Normale Supérieure,” where Louis Pasteur was teaching chemistry, and to the “Ecole Polytechnique;” he chose the former.
In 1877, when he was 23, Sabatier won first place in the competitive national physics agregation examination (agregation is a competitive examination for teaching in high schools). After teaching a few months in the Lycée of Nîmes, Louis Pasteur and Marcelin Berthelot each offered him a position as an assistant in their laboratory. Surprisingly, he chose Berthelot, an anticlerical and materialist man, philosophically opposed to Sabatier’s opinions, instead of Pasteur, a practicing Catholic with a philosophy closer to Sabatier’s. With Berthelot, he completed a doctoral thesis on The Thermochemistry of Sulfides. In 1882, he obtained a position at Toulouse, where he became a professor in 1884 at the age of 30.
Toulouse during the 1880s was a large, rich city with 150 000 inhabitants. In Sabatier’s time, the economy of the city was essentially commercial and agricultural activities with little industrialization. When Sabatier arrived at Toulouse, the Faculty of Sciences was in very poor condition. The decrepit faculty rooms were said to have looked like an alchemist’s cave. Bunsen burners were rare and charcoal stoves were used for heating retorts and flasks. Sabatier rearranged basement rooms at the old faculty building to create a larger laboratory for teaching and research and he introduced new apparatus for research.
In his teaching, Sabatier was an innovator, utilizing Mendeleiev’s periodic table and discarding the notation of chemical equivalence, preferring atomic notation. This is an area in which he disagreed with Berthelot.
|The 12 October 2012 opening of a museum dedicated to Paul Sabatier in the library of the Ecole Nationale Supérieure des Industries et Arts Chimiques de Toulouse. Armand Lattes is on the far right.
Throughout his career, Sabatier remained faithful to his roots in provincial France, turning down many offers of more attractive positions, notably as successor to Moissan at the Sorbonne and to Berthelot at the “Collège de France.” He would have had much greater income potential and more research opportunities in Paris. Furthermore, Toulouse was not a true university at the time since it had only three separated faculties when four was the minimum to become a university. This later changed when Toulouse became one of 17 national universities.
In 1905, Sabatier was elected dean of the Sciences Faculty, a post which he occupied until 1929. Very much ahead of his time, he successfully presided over the establishment of new institutes for applied science: chemistry in 1906, electrotechnic and applied mechanics in 1907, and agriculture in 1909. These institutes were the roots of the present Institut National Polytechnique de Toulouse.
For the first 10 years of his research, Sabatier focused on thermochemistry and physical chemistry, continuing his studies of sulfur and sulfides, but one scientific event and an encounter with Jean-Baptiste Senderens changed his research orientation.
Senderens, a Catholic priest who had taught chemistry at the Institut Catholique de Toulouse since 1882, had been working with Sabatier’s predecessor, Edouard Filhol. When Filhol died, Senderens completed his doctoral thesis in Sabatier’s laboratory. After his thesis he decided to continue working as a “post doctoral researcher” in the laboratory.
|Paul Sabatier's laboratory in the 1920s.
In 1890, Ludwig Mond and coworkers had synthesized the nickel carbonyl compound by direct action of carbon monoxide on very finely divided nickel. This work encouraged Sabatier to study the reaction of “incompleted” or “unsaturated” molecules on different metals. Between 1893 and 1894, Sabatier and Senderens succeeded in fixing nitrogen peroxide on copper (Cu2NO2), nickel and iron; they named these compounds “Nitro Metals.”
In 1896, they learned that Moissan and Moureu had tried to fix acetylene on the same metals. They had passed a current of acetylene on finely divided iron, cobalt, and nickel—freshly reduced from their oxides by hydrogen—and observed a brilliant incandescence, deposition of large quantities of carbon on the metals, formation of benzene, and the evolution of a gas they judged to consist of hydrogen, but they did not analyze the gas!
Having made certain that Moissan was not thinking of continuing the study of the reaction, Sabatier and Senderens repeated the experiment by using ethylene instead of acetylene. When a stream of ethylene was directed to nickel, cobalt, or iron, which had been freshly reduced, they observed the same results as Moissan and Moureu. However, the gas that left the apparatus was not hydrogen, but consisted mainly of ethane, a saturated molecule. Ethane could arise only from hydrogenation of ethylene, and this hydrogenation had been induced by the metal. In fact, if a mixture of ethylene and hydrogen is directed on reduced nickel, the ethylene is hydrogenated in ethane and the same metal can be used indefinitely (June 1897).
Sabatier and Senderens studied in depth the hydrogenation of unsaturated hydrocarbons and then turned to the next challenging problem: the hydrogenation of benzene; with the same experimental method they obtained practically pure cyclohexane in 1901. After these successes, Sabatier was absolutely confident of the general nature of the experimental method they were using when he stated: “Vapor of the substance, together with an excess of hydrogen, is directed on to freshly reduced nickel held at a suitable temperature (between 150° and 200°C).”
In 1912, Sabatier was awarded the Nobel Prize in chemistry: “for his method of hydrogenating organic compounds in the presence of finely divided metals whereby the progress of organic chemistry has been greatly advanced in recent years.” He shared the prize with Victor Grignard who received it for discovering organomagnesium compounds. In 1913, Sabatier was the first scientist elected to a newly created section of the French Academy of Sciences for people not living in Paris.
After 1901, Sabatier went from one type of reaction to another, transforming unsaturated or functionalized compounds in saturated or newly functionalized compounds. Among these reactions two were particularly interesting:
- the transformation of water gas, the domestic gas used at that time, which contained small quantities of toxic carbon monoxide, into a completely nontoxic gas
- the production of the major types of natural petroleum (Pennsylvanian, Romanian, Galician, Bakou) by modifying conditions for hydrogenating acetylene
Besides hydrogenation and other catalytic reactions, Sabatier showed the reversibility of the catalytic process: the same catalyst could be used for the direct and the reverse reaction (hydrogenation and dehydrogenation). One of his most important contributions toward the development of catalysis was his hypothesis about this phenomenon: “Powdered nickel is comparable in every way with a ferment and, as in the case of the living organism which constitutes ferments, infinitesimal doses of certain substances are sufficient to attenuate and even suppress altogether their functional activities.”
Last but not least, Sabatier was the father of the chemical theory of catalysis. For him, in catalysis, a temporary instable intermediate between the catalyst and one of the reactants forms on the surface of the catalyst. That theory was translated into poetry by the rector Paul Lapie in 1913 during a local ceremony: “What is catalysis? The favorite method of Mr. Sabatier? It is the synthesis whereby two bodies, not having spontaneously a very great affinity, consent to be joined when a metal presides over their wedding. If some metals exert this curious magistracy, we knew that before Mr. Sabatier. But we attended to this ceremony only in one case where one side of the married couple was oxygen. The Toulousain scientist has showed that hydrogen is able to play the same role and he has accurately defined the conditions whereby it is ready for use . . . Since nickel, for example, is absolutely necessary for combining acetylene and hydrogen, we must assume that nickel begins to attract hydrogen, but the capricious hydrogen soon breaks with the metal for joining with acetylene. Eyes only perceive one combination under the presence of a passive metal; the mind can explain the facts only as two weddings separated by one divorce.”
Sabatier’s discoveries lay at the root of most of the giant chemical industries of today: 90 percent of all commercially produced chemicals involve catalysis at some stage in the process of their manufacture (e.g., petroleum treatment, petrochemicals, chemical synthesis, synthetic fuels, fat hydrogenation). The same principles Sabatier outlined also apply to the ubiquitous automotive catalytic converter, which breaks down some of the more harmful byproducts of automotive exhaust.
|In the Tranquility node aboard the International Space Station, NASA Astronaut Doug Wheelock, Expedition 25 commander, works to install the new Sabatier. Photo Credit: NASA
Nanotechnologies and nanoparticles represent a new frontier in catalysis because the total surface area of a solid has an important effect on the catalytic reaction rate: the smaller the catalyst, the larger the surface area for a given mass of particles. Gold is an excellent example of this assertion: traditionally regarded as inactive as a catalytic metal, gold can act as a catalyst in the shape of 3-5 nm particles.
Finally, catalysis is one of the 12 principles of green chemistry. Catalysis impact the environment by increasing the efficiency of industrial processes or by playing a direct role in the environment. A notable example is the synthesis of fuels from carbon dioxide and hydrogen. At the beginning of the twentieth century, Paul Sabatier developed a process using a catalyst that reacts with carbon dioxide and hydrogen to produce methane and water.
This reaction provides a way to produce water by using byproducts of current life-support systems onboard the International Space Station: it provides a way to produce water without the need to transport it from Earth. The system was integrated into the station’s water recovery system in October 2011. The six astronaut-crew aboard the ISS now has water synthesized by this reaction: Hydrogen is a waste product of the oxygen generation system; Carbon dioxide is generated by crew metabolism (respiration by individuals). Water is retained and methane is vented outside of the space station. The “Sabatier Reaction System” could produce as much as 2 500 litres of water per year.
Paul Sabatier was a very reserved man. He was fond of art and gardening. He married Germaine Herail and they had four daughters. He survived his wife by 43 years and died on 14 August 1941 at the age of 87. He had worked for 57 years in Toulouse.
last modified 5 October 2013.
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