The Haber-Bosch Process
By,
Max MacMackin
&
Cory Lillie
It’s the end of the nineteenth century, the human population has continued
its population growth but the earth as a whole had already been discovered
during the various periods of industrialization of the human race. There is no new
land to be found and much of the land that is still available for farming has been
farmed for hundreds of centuries. “Cereal crops were the staple of the human
diet and as a result farmers had to develop a way to successfully grow enough
crops to support the population. They eventually learned that fields needed to be
able to rest between harvests and that cereal crops and grains could not be the
only crop planted. In order to restore their fields, farmers began planting other
crops and when they planted legumes they realized that the cereal crops planted
later did better. It was later learned that legumes are important to the restoration
of agriculture fields because they add nitrogen to the soil.” (site1) The land was
still very used up despite this newfound way to help revitalize the soil, some
scientists expected mass starvation if a solution could not be found to make
crops more productive in overly farmed areas and to increase grain production
and agriculture in new areas like Russia, the Americas and Australia. It was only
“in the late 1800's and early 1900's scientists, mainly chemists, began looking for
ways to develop fertilizers by artificially fixing nitrogen the way legumes do in
their roots. ”(site1) It was Fritz Haber, in 1909, who first found a way to
synthesize ammonia in a lab and later Carl Bosch, in 1912, who turned Fritz
Haber's process into something that could be done on a commercial level. It is
believed that this process currently “ is estimated to support food for at least a
third of the Earth’s population.”(Helmenstine).
Fritz Haber, the second half of the Haber-Bosch process, was a German
scientist. He was born on December 9, 1868 in Breslau, Prussia. He was born
into one of the oldest families of the town, as the son of Siegfried Haber, a
merchant of dyes and pigments although his mother did die during childbirth
leading to a lifelong strain on his relationship with his father. Haber received his
early education at the local gymnasium although he did many chemical
experiments throughout his childhood. He began his study of chemistry in 1886
but was interrupted by a year of military service after a year and a half of college
at Heidelberg. After his military service he transferred to the Charlottenberg
Technische Hochschule in Berlin, from which he received a doctorate in 1891 for
work done under Karl Liebermann. After graduation there was a short period of
his life, about 3 years, that found Haber doing various industrial work, some of
which was for his father, with short periods of time over those years spent doing
some postdoctoral study at the Technische Hochschule in Zürich and the
University of Jena. Haber was married twice in his life. His first wife was Clara
Immerwahr with whom he has a son Hermann. His second marriage was to
Charlotta Nathan with whom he had to kids, a daughter, Eva, and son, Ludwig.
Both marriages ended in Haber’s wife leaving him. “In 1894 Haber was appointed
as an assistant in the Department of Chemical and Fuel Technology at the
Fridericiana Technische Hochschule in Karlsruhe. Here he rapidly worked his
way through the academic ranks to become a full professor in 1906.”(site4) It
was in 1904 that Haber started to form a growing interest in the thermodynamics
of gas reactions where his work in this area soon focused on the synthesis of
ammonia gas from nitrogen and hydrogen gas and its potential as a method of
nitrogen fixation. “By 1908 Haber was able to show that the use of high
pressures in combination with a suitable catalyst made ammonia synthesis
practical, and the next year the process was turned over to the German chemist
Carl Bosch at BASF Aktiengesellschaft for industrial development of what is now
known as the Haber-Bosch process.”(site4) For his work in this field the Nobel
Prize in Chemistry 1918 was awarded to Fritz Haber "for the synthesis of
ammonia from its elements".
German chemist Carl Bosch is the other half of the namesake to the
Haber-Bosch process. Carl Bosch was born at Cologne, Germany on August 27,
1874, and grew up there with his father, Carl Friedrich whom owned a
wholesales firm with a workshop for gas and water installations. Carl was the
eldest of six kids and grew up in a very opened-minded atmosphere,
uncharacteristic of the time, Carl’s father never punished his kids in any way.
“From 1894 to 1896 he studied metallurgy and mechanical engineering at the
Technische Hochschule in Charlottenburg, but started reading chemistry at
Leipzig University in 1896. He graduated under Professor Wislicenus with a
paper on organic chemistry in 1898. He entered the employ of the Badische
Anilin- und Sodafabrik, Ludwigshafen, Rhine as a chemist in April 1899 and
participated actively in the development of the then new industry of synthetic
indigo under the guidance of Dr. Rudolf Knietsch.” (SITE5) Around 1900 Carl
Bosch started to become interested in the problem of the fixing nitrogen from the
air to a usable form. Some of his first experiments to do with this issue involved
metal cyanides and nitrides. Bosch got a huge opportunity when, in 1908, “the
Badische Anilin- und Sodafabrik acquired the process of high-pressure synthesis
of ammonia, which had been developed by Fritz Haber at the Technische
Hochschule in Karlsruhe.”(site5) Bosch’s job was to take Haber’s table top highpressure synthesis of ammonia and developing this process on a large, industrial
scale. He accomplished this and from this work Bosch succeeded in working out
methods for the industrial production of nitrogen fertilizers, thus providing
practically every country in the world with sufficient fertilizers for agricultural
purposes. “In 1931 Bosch was awarded the highest international honor, the
Nobel Prize for Chemistry, jointly with Friedrich Bergius, for their contributions to
the invention and development of chemical high pressure methods.”(SITE5)
“In 1898 the British chemist William Crookes warned that the world’s
population would soon outstrip its food production unless crop yields were
increased through the use of nitrogen fertilizers.”(site4) In 1905, German chemist
Fritz Haber published The Thermodynamics of Technical Gas Reactions
(Thermodynamik technischer Gasreaktionen). This book more concerned about
the industrial application of chemistry than to its theoretical study. In it, Haber
inserted the results of his study of the equilibrium equation of ammonia: N2 (g) +
3 H2 (g)
2 NH3 (g) + ΔH. This equation is what gave Haber an upper hand in
later endeavors in nitrogen fixation. In 1907, spurred by a scientific rivalry with
Walther Nernst, solving the nitrogen fixation problem became Haber's top priority.
A few years later, Haber used results published by Nernst on the chemical
equilibrium of ammonia and his own familiarity with high-pressure chemistry and
the liquefaction of air to develop a new nitrogen fixation process. “The Haber
process takes nitrogen gas from air and combines it with molecular hydrogen gas
to form ammonia gas. This is an exothermic reaction, meaning it releases energy
so that the sum of the enthalpies of N2 and H2 (the reactants) is greater than the
enthalpy of NH3 (the products). N2(g) + 3H2(g) → 2NH3(g) ΔH=-92.4 kJ which is
a reversible reaction: 2NH3(g) → N2(g) + 3H2(g) ΔH=+ 92.4 kJ mol-1. In
layman's terms, methane and steam combine to form hydrogen and carbon
monoxide, which in turn releases hydrogen. The hydrogen then combines with
oxygen from the air to produce water. Finally, nitrogen gas is released which
combines with hydrogen gas to form ammonia. This takes place under high
pressure and temperature and with a catalyst”(site7) It became Carl Bosch's job
to take this process from the small tabletop process in its current form to an
industrial sized plant when Badische Anilin- und Sodafabrik acquired the
process. “This task involved the construction of plant and apparatus which would
stand up to working at high gas pressure and high reaction temperatures.
Haber's catalysts, osmium and uranium had to be replaced by a contact
substance that would be both cheaper and more easily available. Bosch and his
collaborators found the solution by using pure iron with certain additives. Further
problems that had to be solved were the construction of safe high-pressurized
blast furnaces, a cheap way of producing and cleaning the gases necessary for
the synthesis of ammonia. Step by step Bosch went on to using increasingly
larger manufacturing units and thus created the industry that deals with the
production of synthetic ammonia according to the high-pressure process. From
this work resulted the second task of making the thus won ammonia available for
use in industry and agriculture. Bosch succeeded in working out methods for the
industrial production of nitrogen fertilizers, thus providing practically every
country in the world with sufficient fertilizers for agricultural purposes.
”(http://www.nobelprize.org/)
Fritz Haber will always be remembered for his work in the creation of the
Haber-Bosch process, but when he was alive, he had a totally different
reputation. Haber got a long with his colleagues at work but when it came to his
personal life, it was a complicated situation. One Haber’s reputations I found was
one of an absent husband. In the summer of 1901, Fritz and his fiancée Clara
planned to take a hiking trip together. When Fritz went to buy tickets for the train,
he had his fiancée wait for him outside and after awhile she went into the station
to find that her fiancée had already boarded a train and left her there. He would
constantly show up later for dinner, and would scold his wife when she would
visit him at school. His wife ended up committing suicide ten days after the first
use of chemical warfare. Some believe she did so as a protest. (site)
When I think of the reputations of Fritz Haber and Carl Bosch in today’s
society, the first thing that comes to my mind is the impact they had on the
world’s population. The Haber-Bosch process not only helped increase the
world’s population with the introduction of new fertilizers; it also decreased the
population with the use of chemical warfare.
Fritz Haber was the director of the Institute for Physical Chemistry that
made poisonous chlorine gas. He actively participated in its development and
was an advocate for its use, even though the Hague Conventions of 1899 and
1907 banned poisonous gas. At the outbreak of World War I in 1914, Haber was
asked to devise a method of producing nitric acid for making high explosives.
Later he became one of the principals in the German chemical warfare effort,
devising weapons and gas masks, which led to protests against his Nobel Prize
in 1918. Fritz Haber was the proud recipient of the Iron Cross as an award for his
work.
Carl Bosch, working for BASF, a giant German company, converted the
ammonia production he helped engineer into munitions production for World War
I. Ammonia is the key to fixing nitrogen, the chemical necessary to make either
fertilizer or explosives. Bosch took an active part in designing a new plant deep
inside Germany that provided Germany with the munitions they needed to stretch
out the war.
Both Haber and Bosch were richly rewarded, within Germany with honors
and money, and outside of Germany – both won the Nobel Prize. But both were
directly responsible for the deaths of millions of people in World War I.
Bibliography
•
"Fritz Haber - Biographical". Nobelprize.org. Nobel Media AB 2013. Web. 31 Mar 2014.
<http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1918/haber-bio.html>
•
"Carl Bosch - Biographical". Nobelprize.org. Nobel Media AB 2013. Web. 31 Mar 2014.
<http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1931/bosch-bio.html>
•
Helmenstine, Anne M. "Haber Process or Haber-Bosch Process." About.com Chemistry.
About.com Chemistry. 30 Mar. 2014
<http://chemistry.about.com/od/chemicalreactions/fl/Haber-Bosch-Process.htm>.
•
Goran, Morris Herbert. The Story of Fritz Haber. Norman: University of Oklahoma, 1967.
Print.