Nitrogen II Oxide Reduction Process

Nitrogen(II) oxide in 80 to 90% yield is produced by the catalytic combustion of ammonia in oxygen in the presence of water vapor on a platinum-rhodium catalyst  

1st step production of NO by combustion of ammonia with pure oxygen 

In the BASF process this is reduced with hydrogen to hydroxylamine on a platinum catalyst on carbon substrates suspended in dilute sulfuric acid. In the Inventa process palladium is used. 

The expected formation of ammonia in a side reaction is largely suppressed by process control measures, e.g. high hydrogen pressure, low hydrogen ion concentration and low temperature, and through a selective poisoning of the catalyst. The yield based on nitrogen(ll) oxide is ca. 90%. 

The quantity of ammonium sulfate byproduct is this process is ca. 0.8 kg per kg of caprolactam produced. The hydroxylamine content in the solution amounts to ca. 115 g/L. 

---