Nitrosylsulfuric acid
Nitrosylsulfuric acid is the chemical compound with the formula NOHSO4. It is a colourless solid that is used industrially in the production of caprolactam,[2] and was formerly part of the lead chamber process for producing sulfuric acid. The compound is the mixed anhydride of sulfuric acid and nitrous acid.
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| Names | |
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| IUPAC name
Nitrosylsulfuric acid | |
| Other names
nitrosonium bisulfate, chamber crystals | |
| Identifiers | |
3D model (JSmol) |
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| ChemSpider | |
| ECHA InfoCard | 100.029.058 |
PubChem CID |
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| UNII | |
CompTox Dashboard (EPA) |
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| Properties | |
| HNO5S | |
| Molar mass | 127.08 g/mol |
| Appearance | Pale yellow crystals[1] |
| Density | 1.612 g/mL in 40% sulfuric acid soln |
| Melting point | 70 °C (158 °F; 343 K)[1] |
| Boiling point | Decomposes |
| Decomposes | |
| Solubility | Soluble in H2SO4[1] |
| Hazards | |
| Main hazards | Oxidizer |
| Related compounds | |
Other anions |
NOCl |
Other cations |
NaHSO4 |
Related compounds |
NOBF4 |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
In organic chemistry, it is used as a reagent for nitrosating, as a diazotizing agent, and as an oxidizing agent.[1]
Synthesis and reactions
A typical procedure entails dissolving sodium nitrite in cold sulfuric acid:[3][4]
- HNO2 + H2SO4 → NOHSO4 + H2O
It can also be prepared by the reaction of nitric acid and sulfur dioxide.[5]
NOHSO4 is used in organic chemistry to prepare diazonium salts from amines, for example in the Sandmeyer reaction. Related NO-delivery reagents include nitrosonium tetrafluoroborate ([NO]BF4) and nitrosyl chloride.
In industry, the nitrosodecarboxylation reaction between nitrosylsulfuric acid and cyclohexanecarboxylic acid is used to generate caprolactam:[2]
Safety
Nitrosylsulfuric acid is a hazardous material and precautions are indicated.[1]
References
- George A. Olah, G. K. Surya Prakash, Qi Wang, Xing-Ya Li (2001). Nitrosylsulfuric Acid. E-EROS Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn060. ISBN 978-0471936237.CS1 maint: multiple names: authors list (link)
- Ritz, J.; Fuchs, H.; Kieczka, H.; Moran, W. C. (2002). "Caprolactam". Ullmann's Encyclopedia of Industrial Chemistry. Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a05_031. ISBN 978-3527306732.
- Hodgson, H. H.; Mahadevan, A. P.; Ward, E. R. (1955). "1,4-Dinitronaphthalene". Organic Syntheses.; Collective Volume, 3, p. 341 (diazodization followed by treatment with nitrite)
- Sandin, R. B.; Cairns, T. L. (1943). "1,2,3-Triiodo-5-nitrobenzene". Organic Syntheses.; Collective Volume, 2, p. 604 (diazodization followed by treatment with iodide)
- Coleman, G. H.; Lillis, G. A.; Goheen, G. E. (1939). Nitrosyl Chloride. Inorganic Syntheses. 1. pp. 55–59. doi:10.1002/9780470132326.ch20. ISBN 9780470132326. This procedure generates the nitrosylsulfuric acid as an intermediate en route to NOCl.