Role of Promoters in Haber’s Process

Haber’s Process is also regarded as Haber’s Bosch Process. It is a process by which atmospheric nitrogen is converted into ammonia. This process is mainly used in industries for large scale production of ammonia. This process is named after German Chemists Fritz Haber and Carl Bosch. In 1913 first time ammonia was manufactured using this process. There are different catalysts used in Haber’s process. The ammonia produced through this process is used in fertilisers as a rich nitrogen source. It is also used in herbicides and pesticides to increase the yield of crops.

Haber’s Process

Haber’s Process is the conversion of atmospheric nitrogen into ammonia in the presence of different catalysts. The reaction is carried out at 200-400 atmosphere and at a temperature of 500℃. The reaction of Haber’s Process is

N2 + 3H2 → 2NH3

The catalyst can be iron oxide, magnesium oxide, aluminium oxide.

The reaction is an exothermic process. Applying Le Chatelier Principle under high pressure and low temperature favours the formation of ammonia. 

Catalysts

Catalyst is a substance that increases the rate of the reaction without disturbing the equilibrium. The catalyst does not take part in the reaction itself, that is it is not consumed during the reaction. There are different types of catalysts used in Haber’s process.

• Iron is generally used as a catalyst in Haber’s process. The iron used for this process contains Potassium Hydroxide as the promoter to increase the catalyst’s efficiency.

• At low temperatures, the rate of the reaction can be increased using a catalyst where the iron contains molybdenum either as iron oxide or as a promoter.

• Also, substances like calcium oxide (CaO), Potassium oxide (K2O), Aluminium oxide (Al2O3)and SiO2 are a few of the chemical substances that can replace potassium hydroxide in the normal reaction and act as promoters themselves.

• Initially, Osmium was used as a catalyst in Haber’s process as only a small quantity of ammonia was produced.

Role of Promoters in Haber’s Process

• The promoters like magnesium oxide increase the efficiency of the iron catalyst of Haber’s Process.

• The promoters are also used to maintain the surface area of the catalysts.

• The promoters are also unreactive to hydrogen; they are not easily reduced by hydrogen.

Conclusion

Haber’s Process is also regarded as Haber’s Bosch Process or Haber ammonia process or synthetic ammonia process. It is a process by which atmospheric nitrogen is converted into ammonia in the presence of hydrogen. This process is mainly used in industries for the large-scale production of ammonia. This process is named after German Chemists Fritz Haber and Carl Bosch. Fritz Haber received the Nobel prize for this process in chemistry in 1918. In 1931 Carl Bosch won the Nobel Prize for converting Haber’s Process into a large-scale process using a catalyst under high pressure. In 1913 first time ammonia was manufactured using this process. There are different catalysts used in Haber’s process. The most widely used catalyst is iron, as it is cost-effective, easily available and shows good activity. Often promoters like aluminium oxide and magnesium oxide are used along with the catalyst to increase the efficiency and the surface area of the catalyst. The ammonia produced through this process is used in fertilisers as a rich source of nitrogen, and also used in herbicides and pesticides in order to increase the yield of crops.