Raschig hydroxylamine process
The Raschig hydroxylamine process is an industrial process for producing hydroxylamine, a modification of Fritz Raschig's original synthesis of hydroxylamine.[1] The hydroxylamine is generally used in the manufacture of caprolactam and hence nylon-6, although it also finds use in the semiconductor industry.
Process chemistry
The synthesis is a three step process.[2] First, ammonia is oxidized in air to give nitrogen oxides (preferably dinitrogen trioxide), which react with ammonium carbonate to give ammonium nitrite:
- 2 NH3 + 3 O2 → N2O3 + 3 H2O
- N2O3 + (NH4)2CO3 → 2 NH4NO2 + CO2
The ammonium nitrite is reduced with sulfur dioxide in the presence of ammonia at 5 °C to give diammonium hydroxylaminedisulfonate:
- NH4NO2 + 2 SO2 + NH3 → (NH4)2[HON(SO3)2]
The disulfonate is then hydrolyzed at 100 °C to give hydroxylamine sulfate:
- 2 (NH4)2[HON(SO3)2] + 3 H2O → (NH3OH)2SO4 + 2 (NH4)2SO4
References
- ↑ Raschig, F. Ueber das Verhalten der salpetrigen zur schwefligen Säure. Justus Liebigs Ann. Chem. 1887, 241 (2), 161–252. DOI: 10.1002/jlac.18872410202. Raschig, Fritz Verfahren zur Darstellung von Hydroxylamindisulfonsauren Alkalislatze und von Hydroxylamin aus letzteren. DE Patent 41987, issued 17 December 1887.
- ↑ Maxwell, Gary R. Synthetic nitrogen products: a practical guide to the products and processes; Springer, 2004; pp 376–77. ISBN 0306482258.
External links
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