Haber-Bosch process
The Haber-Bosch process is a significant chemical method developed in the early 20th century that allows for the extraction of nitrogen from the atmosphere and its conversion into ammonia, a crucial building block for various products such as fertilizers, chemicals, and pharmaceuticals. This process addresses the challenge that, despite nitrogen gas constituting about 78% of the Earth's atmosphere, it is largely inert and unavailable for direct use by most living organisms. Pioneered by Fritz Haber in Germany, and later industrialized by Carl Bosch, the process simulates natural biological nitrogen fixation on a commercial scale.
In the Haber-Bosch reaction, one molecule of nitrogen gas (N2) is combined with three molecules of hydrogen gas (H2) to produce two molecules of ammonia (NH3), facilitated by high temperatures and pressures along with an iron catalyst. Annually, over 90 million metric tons of nitrogen fertilizer are produced via this method, playing a vital role in global agriculture.
Historically, the process provided a crucial advantage during World War I, allowing Germany to maintain its armament production despite blockades. However, it is also subject to economic fluctuations, as the cost of fertilizer is influenced by natural gas prices, which can impact agricultural practices. The oil embargo of 1973 notably highlighted this connection, prompting renewed interest in alternative methods of enhancing soil nitrogen content.
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Haber-Bosch process
The Haber-Bosch process, named for Fritz Haber (1868-1934) and Carl Bosch (1874-1940), two Nobel Prize-winning German chemists, was the first commercially successful process to overcome the chemical inertness of nitrogen gas and allow it to be transformed into ammonia, which can be utilized as a nitrogen fertilizer for plant growth.
Definition
The Haber-Bosch process is a chemical process, developed in Germany in the early twentieth century, that enables nitrogen to be obtained from the atmosphere and transformed into ammonia. Afterward, it becomes usable in products such as chemicals, pharmaceuticals, and fertilizers.
Overview
All living things need nitrogen. It is an essential component of compounds such as proteins and amino acids. However, although plants and animals live in a world surrounded by nitrogen gas (78 percent of the atmosphere is nitrogen gas, a relatively inert compound), little of it is available to them. The stability of nitrogen gas, because of the strength of the triple bond in the molecule, means that of all nutrients in the biosphere, nitrogen is one of the least available nutrients for plant and animal growth. Only a few specialized bacteria, in a process called biological nitrogen fixation, are able to utilize the nitrogen gas surrounding them.
Fritz Haber developed the process of extracting ammonia from nitrogen in his laboratory at Karlsruhe, Germany. Carl Bosch made its industrial application possible by scaling up the laboratory process for his employers at Badische Anilin und Soda Fabrik (BASF) in Ludwigshafen am Rhein, Germany.
The Haber-Bosch process mimics biological nitrogen fixation on an industrial scale. One molecule of nitrogen gas (N2) and three molecules of hydrogen gas (H2) are combined to yield two molecules of ammonia (NH3):
N2 + 3H2 ↔ 2NH3
The reaction is reversible, and there is no tendency for ammonia to form unless an enzyme catalyst is used (as in biological nitrogen fixation) or the reaction is conducted at an extremely high temperature (450° Celsius) and extremely high pressure (200 atmospheres or 20.2 million pascals) in the presence of an iron catalyst.
More than 90 million metric tons of nitrogen fertilizer are produced by the Haber-Bosch process each year. Much is used directly for fertilizer. Most, however, is used for other processes, such as production of nitrogen-containing chemicals, pharmaceuticals, and explosives. The Haber-Bosch process, which became a commercial reality when the first plant began operating in 1913, allowed Germany to continue making armaments and explosives despite a blockade of its ports by England in World War I.
The nitrogen in the Haber-Bosch process comes from air, but the hydrogen generally comes from the reaction of natural gas or methane with steam at high temperatures. Consequently, most of the cost associated with the process comes from the hydrocarbons used to heat the system and supply the hydrogen. As a result, the price of fertilizer nitrogen tends to fluctuate with the price of energy. The oil embargo instituted in 1973 by the Organization of Petroleum Exporting Countries (OPEC) had a trickle-down effect on agriculture, since it raised the cost of energy required for the Haber-Bosch process enormously. As a result, it had the unintended effect of stimulating research in biological nitrogen fixation as a cheaper alternative for improving the nitrogen fertility of soil.