THE FATHERS OF THE SCIENCE Fritz Haber (1868 – 1934)
Fritz Haber (1868 – 1934)
From 1886 until 1891 he studied chemistry at the University of Heidelberg under Bunsen, at the University of Berlin under A.W. Hoffmann, and at the Technical School at Charlottenburg under Liebermann. After completing his University studies he voluntarily worked for a time in his father’s chemical business and, being interested in chemical technology, he also worked for a while under Professor Georg Lunge at the Institute of Technology at Zurich. He then finally decided to take up a scientific career and went for one and a half years to work with Ludwig Knorr at Jena, publishing with him a joint paper on diacetosuccinic ester. Still uncertain whether to devote himself to chemistry or physics, he was offered in 1894, and accepted, an assistantship at Karlsruhe by the Professor of Chemical Technology there, Hans Bunte. Here he remained until 1911. Bunte was especially interested in combustion chemistry and Carl Engler, who was also there, introduced Haber to the study of petroleum and Haber’s subsequent work was greatly influenced by these two colleagues.
In 1911 he was appointed to succeed Engler as Director of the Institute for Physical and Electrochemistry at Berlin-Dahlem, where he remained until, in 1933, the Nazi race laws compelled nearly all his staff to resign and Haber, rather than agree to this, himself resigned. He was then invited by Sir William Pope to go to Cambridge, England and there he remained for a while.
In 1898 Haber published his textbook on Electrochemistry, which was based on the lectures he gave at Karlsruhe. In the preface to his book he expressed his intention to relate chemical research to industrial processes and in the same year he reported the results of his work on electrolytic oxidation and reduction, in which he showed that definite reduction products can result if the potential at the cathode is kept constant. In 1898 he explained the reduction of nitrobenzene in stages at the cathode and this became the model for other similar reduction processes.
There followed, during the next ten years, many other electrochemical researches. Among these was his work on the electrolysis of solid salts (1904), on the establishment of the quinone-hydroquinone equilibrium at the cathode, which laid the foundations for Biilmann’s quinhydrone electrode for determining the acidity of a liquid; but Haber invented, in collaboration with Cremer, the glass electrode for the same purposes which is now widely used. This led Haber to make the first experimental investigations of the potential differences that occur between solid electrolytes and their aqueous solutions, which were of great interest to physiologists.
During this period Haber also studied the loss of energy by steam engines, turbines and motors driven by fuels, and sought methods of limiting their loss by electrochemical means. He did not succeed in finding a solution of this problem that was commercially applicable, but he did succeed in finding a fundamental solution for the laboratory combustion of carbon monoxide and hydrogen.
He then turned to the study of flames and did fundamental researches on the Bunsen flame, showing that, in the luminous inner cone of this flame, a thermodynamic water-gas equilibrium is established and that, in its outer mantle, there is combustion of water-gas. This led to a chemical method of determining flame temperatures.
Haber then undertook the work on the fixation of nitrogen from the air for which he was given the Nobel Prize in Chemistry for 1918 (awarded in 1919).
In 1905 he had published his book on the thermodynamics of technical gas reactions, in which he recorded the production of small amounts of ammonia from N2 and H2 at a temperature of 1000° C with the help of iron as a catalyst. Later he decided to attempt the synthesis of ammonia and this he accomplished after searches for suitable catalysts, by circulating nitrogen and hydrogen over the catalyst at a pressure of 150-200 atmospheres at a temperature of about 500° C. This resulted in the establishment, with the cooperation of Bosch and Mittasch, of the Oppau and Leuna Ammonia Works, which enabled Germany to prolong the First World War when, in 1914, her supplies of nitrates for making explosives had failed. Modifications of this Haber process also provided ammonium sulphate for use as a fertilizer for the soil. The principle used for this process and the subsequent development of the control of catalytic reactions at high pressures and temperatures, led to the synthesis of methyl alcohol by Alwin Mittasch and to the hydrogenation of coal by the method of Bergius and the production of nitric acid.
From 1920 until 1926 he experimented on the recovery of gold from sea water, his idea being to enable Germany to meet her war reparations. Greatly depressed by the failure of this project, which he attributed to his own deficiency, he devoted himself to the reorganisation of his Institute, to which he appointed sectional directors with complete freedom in their work. Among these were James Franck, Herbert Freundlich, Michael Polanyi and Rudolf Ladenburg; from the Institute came much work on colloid chemistry and atomic physics. Haber himself, at this time, made great efforts to re-establish the scientific relationships of Germany with other countries and the colloquia which he held every fortnight did much to establish the international repute of his Institute. During his last years he worked on chain reactions and on mechanisms of oxidation and on hydrogen peroxide catalysis.
Apart from the Nobel Prize, Haber received many honours during his life. At Max von Laue’s instigation, the Institute for Physical and Electrochemistry at Berlin-Dahlem was renamed the Fritz Haber Institute after his death.
From Nobel Lectures, Chemistry 1901-1921, Elsevier Publishing Company, Amsterdam, 1966
