Ostwald process
The Ostwald process was developed by a man named Wilhelm Ostwald, after years of researching. It was created in 1902, patented in 1902, he then later was awarded the Nobel-peace prize for his work in 1909. Wilhelm Ostwald was born in Riga, Russian Empire to mother Elisabeth Leuckel and father Gottfried Wilhelm Ostwald (www.nobelprize.org, 1966).This process was and still is a very important process because it is any easy way to create nitric acid in only two steps. Nitric acid, being used in so many things we don't really think about such as fertilizer and explosives...is at high demand. So the process the Wilhelm created is still being used today because it is reliable and the easiest way to create nitric acid for the high demand it is needed for.
The balanced equation for this reaction is different for each step:
Step 1:
4NH3 (g) + 5O2 (gas) → 4NO (gas) + 6H2O (gas)
In this step, ammonia is heated with oxygen. This yields nitric oxide (NO) and water as products.Step 2:
2NO (gas) + O2 (gas) → 2NO2 (gas)
In this step the nitric oxide (NO) that was created in the first is combined with oxygen again to create nitrogen dioxide (NO2).Step 3:
3NO2 (gas) + H2O (liquid) → 2HNO3 (aqueous solution) + NO (gas)
In this step, the nitrogen dioxide is absorbed with water to create nitric acid (HNO3) as an aqueous solution. This also yields nitric oxide (NO).
Step 4:
4NO2 (gas) + O2 (gas) + 2H2O (liquid) → 4HNO3 (aqueous solution)
For this last step, the nitric oxide created along with the nitric acid is recycled and combined with oxygen and water to create a higher concentration of nitric acid (HNO3). This reaction is exothermic because during the process, it releases heat. (www.pem-news.de, n.d.)
Picture
In reference to LeChatelier's principle , since this reaction is exothermic...conditions that would favor the forward reaction and shift the equilibrium to the right would be decreasing the temperature, increase the concentration , and increasing the pressure and volume.
By decreasing the temperature, because this reaction is exothermic, the equilibrium will shift to the left away from the added energy. So for favorable conditions, we would want to decrease the temperature. By increasing the concentration, the equilibrium will shift away from the added product or reactant. Since we are constantly adding water and oxygen for this process as reactants, than increasing the concentration would create favorable conditions for the equilibrium. As for pressure and volume, the equilibrium would shift towards the side of the reaction with the last number of moles to help ease the pressure. So, taking step one's balanced equation as an example...the right side has less moles, so with increasing the pressure it would shift to the right. Which is favorable for the forward reaction.
Because of it's reaction when combined with organic compounds, most industrial probably don't use the most favorable conditions during the Ostwald process while creating because it will produce an unsafe concentration and corrosive tendencies within the nitric acid. This would be a safety hazard, which is actually why nitric acid is used in explosives.
The catalyst that is used for this reaction is a platinum gauze. It would be heated, however sometimes in substitute..a copper wire/rod can serve as a proper catalyst for this process (www.digipac.ca, n.d.).
