History of Ammonia Synthesis

To convert N2 and H2 into ammonia at a reasonable scale, flow reactors are needed that can be operated at high pressures. Until then, high-pressure reactions were mainly carried out in batch processes. Carl Bosch at BASF developed the technology that enabled scaling up to several tons of ammonia per day at 300 bar. 

The catalyst was reformulated by Alwin Mittasch, who synthesized some 2500 different catalysts and performed more than 6500 tests. They arrived at a triply promoted catalyst consisting of a fused iron catalyst, with AI2O3 and CaO as structural promoters and potassium as an electronic promoter. The process was first commercialized by BASF, with the first plant located in Oppau in Germany producing 30 tons per day in 1913. The plant initially produced ammonium sulfate fertilizer, but when the First World War broke out it was redesigned to produce nitrates for ammunition. The plant was expanded and in 1915 it produced the equivalent of 230 tons ammonium per day. 

The development of ammonia synthesis represents a landmark in chemical engineering, as it was the start of large-scale, continuous high-pressure operation in flow reactors, and in catalysis, because the numerous tests of Mittasch provided a systematic overview of the catalytic activity of many substances. 

Why is the synthesis of ammonia so important Nitrogen is an essential component of biological systems, for which amino acids are fundamental building blocks. Although nitrogen accounts for 80% of the air, N2 is among the most stable molecules and is therefore not easily activated. 

Nature incorporates nitrogen via three different routes. One-third comes from nitrogen oxidized by, for example, fires and lightening where the thermodynamic 

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The synthesis of ammonia from its elements ranks as one of the most important discoveries in the history of the science of catalysis, not only because of its industrial application in which synthetic fertilizers have contributed enormously to the survival of mankind, but also from the viewpoint of fundamental science. Even today, some eighty years after the first demonstration of ammonia synthesis, many original scientific papers on the mechanism of the catalytic synthesis of ammonia are still published. Every time a new method, technique, or concept has appeared in the field of heterogeneous catalysis, it has been applied to this reaction. Specific examples of these applications over the years include the concepts of gas equilibrium, activated adsorption, structure sensitivitystoichiometric number and kinetic studies, " nonuniform surfaces, the measurements of surface area, surface composition and promoter distributions, and the use of isotopic and spectroscopic techniques. In particular, various surface science techniques have been applied successfully to this reaction system over well-defined single crystal surfaces in recent years. In this way the effect of promoters on the iron catalyst has been elucidated. Accordingly, the history of ammonia synthesis parallels not only that of industrial catalysis, but also the development of the science of catalysis. 

Review articles on each of the topics relevant to ammonia synthesis follow in this book. This chapter contains the history of ammonia synthesis, with particular emphasis on the story of how ammonia has come to be manufactured on the... 

The exact mechanism of activation of carbon dioxide is still unrevealed. Great research efforts are needed to overcome this bottleneck problem in terms of both experimental and computational research. Quantum mechanical modelling gives a better insight to the activation mechanism. Once one identifies the appropriate material which will adsorb even gaseous carbon dioxide and transfer it into the corresponding radical anion, yield products with greater than 10% silver bottom efficiency, in a similar way of ammonia synthesis, then the rest becomes history. 

The synthesis of ammonia was the first large-scale synthesis in the chemical industry to work at high pressure, and the first process that was systematically developed based on chemical engineering concepts. We start with an overview of the history of the synthesis, from successful experiments in the laboratory to the start-up of the first industrial plant. For readers interested in details we refer to Appl (1999), Bakemeier et al. (1997), and Timm (1963). 

Table 1.6 History and development of ammonia synthesis catalysts... 

My narrative (in chapter 5) followed Bosch almost to the end of the World War I, when he organized the expansion of ammonia synthesis and nitrate production at Oppau and the construction of a new ammonia plant at Leuna. Shortly after the war s end, in December 1918, Bosch was delegated to Spa, and in March 1919 to Versailles, as the representative of German industry in the armistice and peace treaty delegations. After his return from France he became the chairman of the BASF board, and in that capacity he had to deal with the worst disaster in the company s history, an explosion at Oppau that caused more than 500 fatalities and destroyed the homes of more than 7,000 people in September 1921. In May 1923 Ludwigshafen was occupied by French troops, and Bosch, who fled across the Rhine, was sentenced in absentia for his refusal to cooperate with French authorities. 

Officially, the history of MCRs dates back to the year 1850, with the introduction of the Strecker reaction (S-3CR) describing the formation of a-aminocyanides from ammonia, carbonyl compounds, and hydrogen cyanide [4]. In 1882, the reaction progressed to the Hantzsch synthesis (H-4CR) of 1,4-dihydropyridines by the reaction of amines, aldehydes, and 1,3-dicarbonyl compounds [5], Some 25 years later, in 1917, Robinson achieved the total synthesis of the alkaloid tropinone by using a three-component strategy based on Mannich-type reactions (M-3CR) [6]. In fact, this was the earliest application of MCRs in natural product synthesis [7]. 

S.A. Topham, The History of the Catalytic Synthesis of Ammonia, in J.R. Anderson and M. Boudart (Editors), Catalysis, Science and Technology, Springer Verlag, Berlin, 1985, Vol. 7, pp. 1-50. 

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