Gases - Fundamentals of Industrial Chemistry: Pharmaceuticals, Polymers, and Business - page 26

The largest use for nitrogen is to produce ammonia. However nitrogen
also has many industrial uses such as to provide an inert atmosphere in
chemical and metallurgical processes and, in liquid form, as a coolant. In
nature, enzymes convert atmospheric nitrogen into ammonia in a process
known as nitrogen fixation. Nitrogen fixation serves as a source of nitrogen
for proteins and other naturally-occurring molecules.

3.3 AMMONIA

The industrial conversion of nitrogen to ammonia is done by a process known
as the Haber process. In 1908, Fritz Haber invented a process to convert
nitrogen and hydrogen in the presence of an iron catalyst into ammonia. In
1919, he was awarded the 1918 Nobel Prize in Chemistry - a year later due to
suspension of Nobel Prizes during World War 1. One motivation of Haber's
research was to provide Germany with a source of ammonia for the produc-
tion of explosives [18]. Previously, the main source of nitrogen compounds
had been from Chilean saltpeter, sodium nitrate, which was blockaded in
World War I. Haber was also involved in the development of the chemistry
of poisonous gas warfare. The year after he won the Nobel Prize, he was
charged with international war crimes for his role in chemical warfare during
World War I.
Later, Carl Bosch developed the process on an industrial scale. The Nobel
Prize in Chemistry 1931 was awarded jointly to Carl Bosch and Friedrich
Bergius for their contributions to the invention and development of chemical
high pressure methods.
The process is called the Haber process or sometimes, the Haber - Bosch
process. It is estimated that the number of humans supported per hectare of
arable land has increased from 1.9 to 4.3 persons between 1908 and 2008
mainly due to fertilizers provided by the Haber - Bosch process and by 2008,
nitrogen fertilizers were responsible for feeding 48% of the world's popu-
lation [19]. Most ammonia produced is used for fertilizers, either by direct
application or by conversion to solid fertilizers such as urea, ammonium
nitrate, or ammonium phosphate. Nitrogen is a primary nutrient for plants and
large amounts of nitrogen are needed for agriculture. Other uses of ammonia
include the manufacture of chemicals such as acrylonitrile or caprolactam,
and miscellaneous uses such as pulp and paper and refrigeration.

N 2 + 3H 2 2NH 3 + 92 kJ

The process is an equilibrium. Ammonia formation is favored by cold
temperatures and high pressures. However, low temperature means slower