Difference between revisions of "Raschig hydroxylamine process"
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| − | The '''Raschig hydroxylamine | + | The '''Raschig hydroxylamine process''' is an industrial process for producing [[hydroxylamine]], a modification of [[Fritz Raschig]]'s original synthesis of hydroxylamine.<ref>{{citation | last = Raschig | first = F. | title = Ueber das Verhalten der salpetrigen zur schwefligen Säure | journal = Justus Liebigs Ann. Chem. | volume = 241 | issue = 2 | pages = 161–252 | year = 1887 | doi = 10.1002/jlac.18872410202}}. {{citation | inventor-last = Raschig | inventor-first = Fritz | title = Verfahren zur Darstellung von Hydroxylamindisulfonsauren Alkalislatze und von Hydroxylamin aus letzteren | country-code = DE | patent-number = 41987 | issue-date = 1887-12-17}}.</ref> 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== | ==Process chemistry== | ||
| − | The synthesis is a three step process. First, [[ammonia]] is [[Oxidation|oxidized]] in air to give nitrogen oxides (preferably [[dinitrogen trioxide]]), which react with [[ammonium carbonate]] to give [[ammonium nitrite]]: | + | The synthesis is a three step process.<ref name="Maxwell">{{citation | title = Synthetic nitrogen products: a practical guide to the products and processes | first = Gary R. | last = Maxwell | pages = 376–77 | publisher = Springer | year = 2004 | isbn = 0306482258}}.</ref> First, [[ammonia]] is [[Oxidation|oxidized]] in air to give nitrogen oxides (preferably [[dinitrogen trioxide]]), which react with [[ammonium carbonate]] to give [[ammonium nitrite]]: |
| − | : | + | :2 NH<sub>3</sub> + 3 O<sub>2</sub> → N<sub>2</sub>O<sub>3</sub> + 3 H<sub>2</sub>O |
| − | :N<sub>2</sub>O<sub>3</sub> + (NH<sub>4</sub>)<sub>2</sub>CO<sub>3</sub> → | + | :N<sub>2</sub>O<sub>3</sub> + (NH<sub>4</sub>)<sub>2</sub>CO<sub>3</sub> → 2 NH<sub>4</sub>NO<sub>2</sub> + CO<sub>2</sub> |
The ammonium nitrite is reduced with [[sulfur dioxide]] in the presence of ammonia at 5 °C to give [[diammonium hydroxylaminedisulfonate]]: | The ammonium nitrite is reduced with [[sulfur dioxide]] in the presence of ammonia at 5 °C to give [[diammonium hydroxylaminedisulfonate]]: | ||
| − | :NH<sub>4</sub>NO<sub>2</sub> + | + | :NH<sub>4</sub>NO<sub>2</sub> + 2 SO<sub>2</sub> + NH<sub>3</sub> → (NH<sub>4</sub>)<sub>2</sub>[HON(SO<sub>3</sub>)<sub>2</sub>] |
The disulfonate is then hydrolyzed at 100 °C to give [[hydroxylamine sulfate]]: | The disulfonate is then hydrolyzed at 100 °C to give [[hydroxylamine sulfate]]: | ||
| − | :(NH<sub>4</sub>)<sub>2</sub>[HON(SO<sub>3</sub>)<sub>2</sub>] + | + | :2 (NH<sub>4</sub>)<sub>2</sub>[HON(SO<sub>3</sub>)<sub>2</sub>] + 3 H<sub>2</sub>O → (NH<sub>3</sub>OH)<sub>2</sub>SO<sub>4</sub> + 2 (NH<sub>4</sub>)<sub>2</sub>SO<sub>4</sub> |
==References== | ==References== | ||
{{reflist}} | {{reflist}} | ||
| + | |||
| + | ==External links== | ||
| + | *[http://shippai.jst.go.jp/en/Detail?fn=0&id=CC1000050&] | ||
| + | *[http://www.csb.gov/assets/document/Concept_case_study.pdf] | ||
[[Category:Hydroxylamine]] | [[Category:Hydroxylamine]] | ||
Latest revision as of 20:35, 3 July 2010
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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