Habers First Experiments with Ammonia

Haber s work on ammonia synthesis began during the summer of 1904 not because of any planned, determined effort to solve an elusive task, but because of an unexpected request from the Osterreichische Chemische Werke in Vienna, a company set up by the brothers O. and R. Margulies. Haber did not immediately take up the offer he advised the brothers to take what was at that time the easiest route and recover by-product ammonia from coking. As he knew something about Ostwald s earlier work on the problem (but not about his unsuccessful deal with BASF and about the withdrawal of Ostwald s 1900 patent application), he wrote to him hoping that he would cooperate with the Margulies brothers. 

Eventually Haber decided to proceed with fundamental experiments, and he received generous financial support from the Viennese company for his work. As he summed it up in his Nobel lecture, the challenge was both simple and exceedingly difficult  

We are concerned with a chemical phenomenon of the simplest possible kind. Gaseous nitrogen combines with gaseous hydrogen in simple quantitative proportions to produce ammonia. The three substances involved have been well known to the chemist for over a hundred years. During the second half of the last century each of them has been studied hundreds of times 

Indeed, few reactions appear simpler than Nz + 3Hz 2NH3. 

But because none of the many attempts to achieve a spontaneous union of the two gases to form ammonia had ever succeeded with absolute certainty, a widely held belief arose that such a synthesis might not be possible—and such feelings deterred further attempts at the necessary theoretical research. 

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The catalytic activity of iron was already known well before the advent of industrial ammonia synthesis. Ramsay and Young used metallic iron for decomposing ammonia. Perman [236], as well as Haber and Oordt [237], conducted the first catalytic synthesis experiments with iron at atmospheric pressure. Nernst [12] used elevated pressures of 5-7 MPa. Pure iron showed noticeable initial activity which, however, could be maintained for longer operating periods only with extremely pure synthesis gas. 

Alwin Mittasch joined BASF in 1904 as a co-worker of Carl Bosch and started the search for suitable ammonia synthesis catalysts soon afterward. These efforts were considerably intensified after Haber s successful experiments but, at first, only with limited success. He mentioned (4) In particular iron failed, despite wide variations of the preparation conditions and admixtures. The breakthrough was obtained by accident A sample of Swedish magnetite left over from other experiments was investigated on November 6, 1909, by Mittasch s collaborator Dr. Wolf and exhibited remarkably high ammonia yields. The decisive patent application of January 9, 1910, says the following ... 

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