The Haber-Bosch Process
AN INDUSTRIAL PROCESS FOR PRODUCING AMMONIA
• Reaction was discovered by Bosch and was published in
his 1905 book1,2
• Fritz Haber received a Nobel price in 1918 for the
synthesis of ammonia from its constituents elements2
• Carl Bosch made it an industrial process to make
• First commercial high-pressure synthesis of ammonia in
19132 using Haber process
• Ammonia is very useful – explosives, fertilizer, Ostwald
(1) Haber, F. The synthesis of ammonia from its elements Nobel Lecture, June 2, 1920. Resonance. 2002, 7, 86-94.
(2) Fritz Haber – Biographical. 2014. Nobelprize.org. http://www.nobelprize.org/nobel_prizes/chemistry/laureates/1918/haber-bio.html (accessed Mar 16, 2016).
(3) Modak, J.M. Haber process for ammonia synthesis. Resonance. 2002, 7, 69-77.
Image from https://fr.wikipedia.org/wiki/Proc%C3%A9d%C3%A9_Haber
Nitrogen from air
Hydrogen from natural gas
3𝐻2(𝑔) + 𝑁2(𝑔) ⇌ 2𝑁𝐻3(𝑔) ∆H = -92.44 kJ/mol
(4) Appl, M. Ammonia. In Ullmann's Encyclopedia of Industrial Chemistry. Wiley-VCH: Weinheim, Germany, 2006.
Optimizing reaction rate and yield
•Forward reaction is exothermic
•Ammonia yield is favoured at low temperatures
•But reactions are slower at lower temperatures
•Fe catalyst increases reaction rate
𝟑𝑯 𝟐(𝒈) + 𝑵 𝟐(𝒈) ⇌ 𝟐𝑵𝑯 𝟑(𝒈) ∆H = -92.44 kJ/mol