Editing Ostwald process (section)

=== Secondary oxidation ===
The nitric oxide (NO) formed in the prior catalysed reaction is then cooled down from around 900˚C to roughly 250˚C to be further oxidised to nitrogen dioxide (NO<sub>2</sub>)<ref>{{cite web|author=Afolayan Ayodele S |date=7 December 2007 |title=Design of a Plant to Produce 20,000 Litres per Day of Nitric Acid From Ammonia and Air (Using Oswald Process) |website=Repository Futminna |access-date=24 May 2024 |url=http://repository.futminna.edu.ng:8080/jspui/bitstream/123456789/24229/1/OCRENGR0183891.pdf}}</ref> by the reaction:

{{chem2|2NO + O2 -> 2NO2}} (Δ''H'' = -114.2 kJ/mol)<ref>{{Cite journal |last1=Grande |first1=Carlos A. |last2=Andreassen |first2=Kari Anne |last3=Cavka |first3=Jasmina H. |last4=Waller |first4=David |last5=Lorentsen |first5=Odd-Arne |last6=Øien |first6=Halvor |last7=Zander |first7=Hans-Jörg |last8=Poulston |first8=Stephen |last9=García |first9=Sonia |last10=Modeshia |first10=Deena |date=2018-08-08 |title=Process Intensification in Nitric Acid Plants by Catalytic Oxidation of Nitric Oxide |journal=Industrial & Engineering Chemistry Research |language=en |volume=57 |issue=31 |pages=10180–10186 |doi=10.1021/acs.iecr.8b01483 |issn=0888-5885|doi-access=free }}</ref> 

The reaction:

{{Chem2|2NO2 -> N2O4}}  (Δ''H'' = -57.2 kJ/mol)<ref>{{Cite web |date=24 May 2024 |title=21.1 The Effect of Temperature on the NO2/N2O4 Equilibrium |url=https://chemed.chem.purdue.edu/genchem/demosheets/21.1.html |access-date=24 May 2024 |website=chemed.chem.purdue.edu}}</ref>

also occurs once the nitrogen dioxide has formed.<ref name=":0">{{Citation |last1=Liu |first1=Yunda |title=Static and dynamic simulation of NOx absorption tower based on a hybrid kinetic-equilibrium reaction model |date=2014-01-01 |work=Computer Aided Chemical Engineering |volume=34 |pages=363–368 |editor-last=Eden |editor-first=Mario R. |url=https://www.sciencedirect.com/science/article/pii/B9780444634337500456 |access-date=2024-05-24 |series=Proceedings of the 8 International Conference on Foundations of Computer-Aided Process Design |publisher=Elsevier |doi=10.1016/b978-0-444-63433-7.50045-6 |last2=Bluck |first2=David |last3=Brana-Mulero |first3=Francisco |isbn=978-0-444-63433-7 |editor2-last=Siirola |editor2-first=John D. |editor3-last=Towler |editor3-first=Gavin P.}}</ref>