Paul Sabatier 1912 (70)

Paul Sabatier 1912 (70)

Paul Sabatier was born on 5 November 1854, in Carcassonne, France. He pursued his education at the Faculty of Science in Toulouse, where he studied chemistry under the guidance of renowned chemist Henri Moissan. Sabatier’s dedication and enthusiasm for research became evident during his formative years. Sabatier’s career was marked by groundbreaking research in the field of catalysis. His collaboration with Victor Grignard led to the development of the Sabatier–Grignard reaction, a fundamental process in organic chemistry. This reaction revolutionized the synthesis of hydrocarbons and contributed significantly to the understanding of chemical reactions involving metal catalysts.

Sabatier’s pioneering work extended to the field of catalytic hydrogenation, where he discovered that certain metal catalysts could facilitate the addition of hydrogen to organic compounds. This discovery had profound implications for industrial processes and laid the foundation for the field of heterogeneous catalysis. Paul Sabatier passed away on 14 August 1941 in Toulouse, France. He was awarded the Nobel Prize in Chemistry in 1912 for his development of the catalytic hydrogenation method. This recognition solidified his status as a leading figure in the scientific community and brought attention to the vital role of catalysis in chemical transformations. Paul Sabatier’s legacy is still evident today, as his work laid the groundwork for various applications in the chemical industry, including the production of pharmaceuticals, plastics, and fuels. His insights into catalysis have continued to inspire generations of chemists and researchers.

Sabatier’s early work lay in the fields of inorganic and physical chemistry. In the former he published a series of papers on the sulphides, including one on hydrogen disulphide (1886). In an examination of the properties of the oxides of nitrogen he, together with his pupil J. B. Senderens, discovered a number of new metallic nitrides. The deep blue nitroso-disulphonic acid and a series of complex cupric salts must be mentioned as other interesting achievements in preparative inorganic chemistry.

His early investigations in physical chemistry comprised a series of thermochemical measurements inspired by his professor, Marcelin Berthelot, a study of the velocity of transformation of metaphosphoric acid and the partition of a base between two acids.

It was not until he had been in the university of Toulouse for fifteen years that he commenced his remarkable investigations on the application of catalytic methods to organic compounds. When Sabatier commenced his investigations on the catalytic properties of finely divided metals, little was known about their mode of reaction, although the phenomenon of catalysis had been well established. The investigations of Faraday had led to the formulation of a physical theory of catalysis which postulated the absorption of gases in the pores of the solid catalyst. During the process of this absorption there is a simultaneous liberation of heat and it was imagined that the imposition of the two physical restraints, namely the elevation of the temperature and the compression to high densities was the cause of the acceleration of the chemical reaction between the reactants when brought into contact with the catalyst. This purely physical concept of the mode of action of a heterogeneous catalyst was not accepted by Sabatier, who quite early in his investigations pointed out a number of anomalies.

Thus, porous carbon should on this view be a universal catalyst for all gas reactions, but, as he observes, it is but a mediocre catalyst except for the formation of carbonyl chloride. Again, whilst metals in a finely divided state absorb considerable quantities of gas, these absorptions are somewhat specific being ‘characterized by a sort of selective affinity’. We see here the first suggestion of the present accepted view that there are in fact two kinds of adsorption: that due to the dispersive forces termed Van der Waals’ and that in which an electronic switch has occurred, termed chemi-sorption. Sabatier notes generally that one of the most remarkable properties in heterogeneous catalysis requiring explanation is the remarkable specificity exerted in many cases; thus he observes that zinc oxide decomposes formic acid into hydrogen and carbon dioxide exclusively, but at the same temperature titanium oxide gives carbon monoxide and water exclusively.

In his argument against the physical theory he finally comments that a sharp distinction would have to be made between the modus operandi of homogeneous and heterogeneous catalysts respectively, a difference it is scarcely logical to assume. Sabatier formulated a chemical theory of catalysis in which the temporary formation of unstable chemical compounds as intermediary steps is postulated. These determine on his view the direction and speed of the reaction. This concept was developed by consideration of several types of what he termed reciprocal catalysis. Thus hydrogen peroxide solutions decompose relatively slowly in the cold; the same is true for chromic acid solutions in dilute sulphuric acid. On mixing the two solutions there is a rapid decomposition with a brisk evolution of oxygen. The decomposition takes place in a proportionated manner corresponding to 3H20 2: 2H2C r0 4. The clue to this reciprocal catalytic effect is to be found in the formation of the dark blue compound perchromic acid as a result of stoichiometric combination between the reactants in each system.

Sabatier developed in a systematic manner this concept of a temporary unstable combination as the explanation of catalysis in general. Sabatier and his co-workers contributed to many and varied branches of catalytic reactions applied to synthesis in organic chemistry. An indication of his versatility can be obtained from the following cases.

Sabatier’s examination of reactions involving catalytic hydrogenation is perhaps the most comprehensive of any investigation undertaken in exploring a new method or a new reaction. This examination which was commenced in 1897 and terminated some twenty years later, was carried out with comparatively simple apparatus which, however, were so well conceived that they remain as the standard procedure at the present time. Sabatier was assisted in this work by several collaborators, many of whom at a later date made definite contributions to the science of catalytic chemistry. Amongst these may be mentioned especially the Abbe Senderens, Mailhe and Murat. The general method of catalytic hydrogenation developed by Sabatier consisted in passing the vapours of the organic substance together with hydrogen over a suitably heated catalyst at the appropriate temperature. Sabatier was fully alive to the technical implications pf catalytic hydrogenation, and indeed, an imposing list of patent applications stood in his name. It is one of those unfortunate chance occurrences that Sabatier’s interests were not directed to liquid phase hydrogenation—a process which revolutionized the fat industry throughout the world. The first attempt to hydrogenate liquid fats was only made six years after Sabatier’s original investigations had been published. At a still later date the use of high pressures originally proposed and developed by Ipatiev must be regarded as another distinct advance in the technical application of Sabatier’s principles. Catalytic hydrogenation is frequently carried out in the laboratory with the aid of platinum or palladium, either in colloidal suspension as a protected colloid, a method originating with Paal, or in the form of finely divided metal, e.g. platinum black intimately mixed with the material to be hydrogenated. Many modifications of the latter method especially the one developed by Willstatter are in everyday use at the present time. Sabatier’s nickel catalyst, so effective in vapour phase hydrogenation, was applied most successfully to liquid phase hydrogenation in the first instance by Ipatiev, the results obtained being quite as effective as those when the rare metals were employed. At the present time nickel in various forms is the most versatile and reliable hydrogenating catalyst.

The particular merit of Sabatier’s work in the field of catalysis lies in the fact that it revealed the great potentialities of the method in the field of preparative organic chemistry. This method on account of its simplicity and elegance is now in everyday use, both in the research laboratory and in the organic chemical industry.

Sabatier was awarded the Lacaze prize of the Academy of Science of Paris in 1897 and the Jecker prize in 1905. In 1912 he was awarded the Nobel prize in chemistry and in 1915 he received the Davy medal from the Royal Society to which he was elected as foreign member in 1918. He was a foreign member of several other scientific societies, notably of the Royal Institution of the Academies of Sciences of Amsterdam and Madrid and of the Royal Society of Bohemia. He was elected Doctor honoris causa of the universities of Louvain and of Saragossa.