The Haber-Bosch ProcessAN INDUSTRIAL PROCESS FOR PRODUCING AMMONIA

Adeyemi Fakorede

History• 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 explosives

• First commercial high-pressure synthesis of ammonia in 19132 using Haber process

• Ammonia is very useful – explosives, fertilizer, Ostwald process

(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

Raw Materials4

Nitrogen from air

Hydrogen from natural gas

3𝐻2(𝑔) + 𝑁2(𝑔) ⇌ 2𝑁𝐻3(𝑔) ∆H = -92.44 kJ/molReaction conditions500 0C200 atmFe catalyst(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

𝟑𝑯𝟐(𝒈) + 𝑵𝟐(𝒈) ⇌ 𝟐𝑵𝑯𝟑(𝒈) ∆H = -92.44 kJ/mol