Bosch, Carl, ammonia synthesis

Bosch, Carl( 1874-1940). Ger scientist who specialized in the ptepn of nitrogen-contg org compds and collaborated with Haber in the synthesis of ammonia. Was director of IGFarbenindustries Refs DC.Krauch.AngChem 53,285-8(1940) 2)P. Muller,SS 35,123-4(1940)... 

In 1909 the German Chemist Fritz Haber discovered a catalyzed process [13], which allowed the synthesis of ammonia (NH3) from the elements hydrogen and nitrogen. He received the Nobel prize in chemistry for his discovery. The Nobel prize for Fritz Haber was a subject of controversy because Haber is also the inventor of war gas (phosgene COCI2), which killed hundreds of thousands of soldiers in World War I. Conscience-stricken, Haber s wife committed suicide. Carl Bosch succeeded to scale up Haber s synthesis from the laboratory scale to industrial production. After World War I other industrialized countries also introduced ammonia synthesis and therefore the consumption of hydrogen increased rapidly. 

BASF high pressure converter for ammonia synthesis, with (inset) Carl Bosch (above) and Fritz Haber (below). Photos courtesy BASF (converter and Haber), and Deutsches Museum, Munich (Bosch). Reproduced from the cover of Chemistry Industry, 2 August 1993, with permission. 

After trying different substances to see which would be most effective, Carl Bosch (see Chemistry Put to Work The Haber Process, page 615) settled on iron mixed with metal oxides, and variants of this catalyst formulation are stiU used today. These catalysts make it possible to obtain a reasonably rapid approach to equilibrium at around 400 to 500 °C and 200 to 600 atm. The high pressures are needed to obtain a satisfactory equilibrium amount of NH3. If chemists and chemical engineers could identify a catalyst that leads to sufficiently rapid reaction at temperatures lower than 400 °C, it would be possible to obtain the same extent of equilibrium conversion at pressures much lower than 200 to 600 atm. This would result in great savings in the cost of the high-pressure equipment used in ammonia synthesis today. 

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 ... 

Haber s scientific iegacy is unquestionable. He devised a method for the direct synthesis of ammonia from nitrogen and hydrogen. His process used high pressure and temperature, together with an osmium catalyst. This method was then adapted for use with an iron catalyst by Carl Bosch (1874-1949), and the process was scaled up for industrial production. The achievement of industrial nitrogen fixation was crucial for the development of inexpensive fertilizers and revolutionized food production worldwide. Haber received the Nobel Prize in Chemistry in 1918 for his work on ammonia synthesis. 

In 1908, Haber, a professor at the University of Karlsruhe, Germany, started a collaboration with the chemist Carl Bosch of the Badische Anilin- und Soda-Fabrik (BASF) at Ludwigshafen. Their 1909 experiment in which 8% of ammonia formed at 550°C and 175 atm confirmed the predictions from chemical thermodynamics and convinced them of the feasibility of ammonia synthesis at an industrial scale. 

Bosch, for once dejected and under strong pressure by the company s directors, turned to Carl Krauch (1887-1968), a young chemist on his team. Krauch solved this last complication on the road to commercial ammonia synthesis by adding ammonia to the solution. Cuprous ammonium formate proved to be an excellent absorber of CO, and Krauch s solution remained in use for decades. The remaining moisture was not removed from the mixture used in the first two commercial plants, but it is taken out in modern processes.If the purified mixture contained excess H, its content was adjusted with nitrogen from liquefied air to the exact stoichiometric ratio of 1 3. 

All of these realities will be taken up in considerable detail in this book. I will first describe nitrogen s unique and indispensable status in the biosphere, its role in crop production, and the traditional means of supplying the nutrient. Then I will concentrate on various attempts to expand natural nitrogen flows by introduction of mineral and synthetic fertilizers. The core of the book is a detailed narrative of the epochal discovery of ammonia synthesis by Fritz Haber and its commercialization by Carl Bosch and BASF. 

Synthesis of ammonia in the Haber-Bosch process is one of the best studied catalytic processes. The process was developed by Fritz Haber and Carl Bosch and patented in 1910 (Haber, 1910) Haber was awarded the Nobel Prize in chemistry in 1918 for this work. Today, almost all ammonia production is based on the Haber-Bosch process, and it is one of the largest chemical processes in the world with a yearly production of approximately 120 million tonnes (from the International Fertilizer Industry Association, World Ammonia Statistics for 2005). The main use of ammonia is as fertilizer for agriculture, which constitutes 80% of the world production. 

The BASF representatives were chemist Carl Bosch and catalyst expert Alwin Mittasch. They were there to find out whether the backing for Haber s nitrogen fixation studies by the head of the managing board, Heinrich von Brunck, had finally paid of Though the apparatus had been tested and found successful, the initial outcome of the demonstration seemed disappointing the apparatus refused to work. Carl Bosch left to attend to other business. Mittasch remained in the laboratory and later in the day was rewarded when the apparatus delivered 100 cubic centimetres of ammonia. He was convinced Haber had overcome the laboratory difficulties involved in the synthesis of ammonia. Patents for the continuous process were filed in Germany and elsewhere, and Haber came to an agreement with BASF over royalties. ... 

Fritz Haber (Breslau, 9 December 1868-Basel, 29 January 1934) studied in Berlin, Heidelberg and Charlottenberg, and worked at first on organic chemistry. In 1894 he became assistant to Bunte at the Technical High School at Karlsruhe, where he became associate professor (1898) and (1906) professor of technical chemistry. Whilst at Karlsruhe he investigated the synthesis of ammonia from its elements (1905, 1915) which afterwards (with the collaboration of Carl Bosch) led to the development of the manufacture of synthetic ammonia by the Badische Co. at Ludwigshafen, although the reaction under pressure (the technical process) was first carried out by Nernst (see above). In 1911 Haber became director of the Kaiser Wilhelm Institute of Physical Chemistry and Electrochemistry at Berlin-Dahlem. He received the Nobel Prize in 1919. He worked on chemical equilibria in flames (1895 f.), the electrolytic reduction of nitrobenzene (1898 f.), autoxidation (1900 f.), the synthesis of nitric oxide in the electric arc (1908 f.), and on many branches of electrochemistry. His books contain useful material, the one on thermodynamics an unsuccessful approach to the Nernst heat theorem. 

Haber, Fritz (1868-1934) German chemist who, with brother-in-law Carl Bosch, invented a process for the synthesis of ammonia from hydrogen and atmospheric nitrogen, thus overcoming the shortage of natural nitrate deposits accessible to the German explosives industry in World War I. Haber s development of the process on an industrial scale provided copious quantities of fertilizers and also prompted the development of the chemical industry and chemical engineering. For his work, Haber received the Nobel Prize in chemistry in 1918. 

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