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Haber Process


The Haber Process equilibrium

The equation for this is:

N2(g) + 3H2(g) <=> 2NH3(g) + 92.4 kJ

. . . and the Kc expression is:

The Haber Process (also known as Haber–Bosch process) is the reaction of nitrogen and hydrogen to produce ammonia.

The nitrogen (N2) and hydrogen (H2) gases are reacted over an iron catalyst (Fe3+) and aluminum oxide (Al2O3) and potassium oxide (K2O) are used as promoters. The reaction is carried out under conditions of 250 atmospheres (atm), 450-500C; resulting in a yield of 10-20%:

N2(g) + 3H2(g) <=> 2NH3(g) + 92.4 kJ

At the beginning of the 20th century there was a shortage of naturally occurring, nitrogen-rich fertilizers, such as Chile saltpeter, which prompted the German Chemist Fritz Haber, and others, to look for ways of combining the nitrogen in the air with hydrogen to form ammonia, which is a convenient starting point in the manufacture of fertilizers. This process was also of interest to the German chemical industry as Germany was preparing for World War I and nitrogen compounds were needed for explosives.

The process was first patented by Fritz Haber in 1908. In 1910 Carl Bosch, while working for chemical company BASF, successfully commercialized the process and secured further patents. It was first used on an industrial scale by the Germans during World War I: Germany had previously imported 'Chilean saltpeter' (NaNO3) from Chile, but the demand for munitions and the uncertainty of this supply in the war prompted the adoption of the process. Without this process, Germany would almost certainly have run out of munitions by 1916, thereby ending the war. The ammonia produced was oxidized for the production of nitric acid in the Ostwald process, and the nitric acid for the production of various explosive nitro compounds used in munitions.

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