Nitrosyl chloride
| Skeletal formula of nitrosyl chloride with measurements | |
| Spacefill model of nitrosyl chloride | |
| Names | |
|---|---|
| Preferred IUPAC name
Nitrosyl chloride[citation needed]
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| Systematic IUPAC name
Nitrooyl chloride[citation needed]
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Other names
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| Identifiers | |
2696-92-6  |
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| ChemSpider | 16641 |
| EC Number | 220-273-1 |
| Jmol 3D model | Interactive image |
| MeSH | nitrosyl+chloride |
| PubChem | 17601 |
| RTECS number | QZ7883000 |
| UN number | 1069 |
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| Properties | |
| NOCl | |
| Molar mass | 65.459 g mol−1 |
| Appearance | Yellow gas |
| Density | 2.872 mg mL−1 |
| Melting point | −59.4 °C (−74.9 °F; 213.8 K) |
| Boiling point | −5.55 °C (22.01 °F; 267.60 K) |
| Reacts | |
| Structure | |
| Dihedral, digonal | |
| Hybridisation | sp2 at N |
| 1.90 D | |
| Thermochemistry | |
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Std molar
entropy (S |
261.68 J K−1 mol−1 |
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Std enthalpy of
formation (ΔfH |
51.71 kJ mol−1 |
| Vapor pressure | {{{value}}} |
| Related compounds | |
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Related compounds
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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 | |
Nitrosyl chloride is the chemical compound with the formula NOCl. It is a yellow gas that is most commonly encountered as a decomposition product of aqua regia, a mixture of hydrochloric acid and nitric acid. It is a strong electrophile and oxidizing agent.
Contents
Structure and synthesis
The molecule is bent. A double bond exists between N and O (distance = 1.16 Å) and a single bond between N and Cl (distance = 1.69 Å). The O-N-Cl angle is 113°.[1]
Production
Since nitrosyl chloride is chemically simple and stable at room temperature and below, it can be produced in many ways.
- Combining nitrosylsulfuric acid and HCl affords the compound. This method is used industrially.[2]
- HCl + NOHSO4 → H2SO4 + NOCl
- A more convenient laboratory method involves the (reversible) dehydration of nitrous acid by HCl[3]
- HNO2 + HCl → H2O + NOCl
- Michael Faraday prepared nitrosyl chloride by reacting palladium with aqua regia:
- Pd + HNO3 + 3 HCl → PdCl2 + 2 H2O + NOCl
- NOCl forms by the direct combination of chlorine and nitric oxide; This reaction reverses above 100 °C.
- Cl2 + 2NO → 2NOCl
- Another method of producing nitrosyl chloride is by direct union of the elements at 400 °C, although there is some regression as above.
- N2 + O2 + Cl2 → 2 NOCl ↔ 2NO + Cl2
Occurrence in aqua regia
NOCl also arises from the combination of hydrochloric and nitric acids according to the following reaction:[4]
- HNO3 + 3 HCl → Cl2 + 2 H2O + NOCl
In nitric acid, NOCl is readily oxidized into nitrogen dioxide. The presence of NOCl in aqua regia was described by Edmund Davy in 1831.[5]
Reactions
NOCl behaves as an electrophile and an oxidant in most of its reactions. With halide acceptors, for example antimony pentachloride, converts to nitrosonium salts:
- NOCl + SbCl5 → [NO]+[SbCl6]−
In a related reaction, sulfuric acid gives nitrosylsulfuric acid, the mixed acid anhydride of nitrous and sulfuric acid:
- ClNO + H2SO4 → ONHSO4 + HCl
NOCl reacts with silver thiocyanate to give silver chloride and the pseudohalogen nitrosyl thiocyanate:
- ClNO + AgSCN → AgCl + ONSCN
Nitrosyl chloride is used to prepare metal nitrosyl complexes. With molybdenum hexacarbonyl, NOCl gives the dinitrosyldichloride complex:[6]
- Mo(CO)6 + 2 NOCl → MoCl2(NO)2 + 6 CO
Applications in organic synthesis
Aside from its role in the production of caprolactam, NOCl finds some other uses In organic synthesis. It adds to alkenes to afford α-chloro oximes.[7] The initial addition of NOCl follows the Markovnikov rule. Ketenes also add NOCl, giving nitrosyl derivatives:
- H2C=C=O + NOCl → ONCH2C(O)Cl
Propylene oxide also undergoes electrophilic addition with NOCl to give an α-chloro-nitritoakyl derivative:
It converts amides to N-nitroso derivatives.[8] NOCl converts some cyclic amines to the alkenes. For example, aziridine reacts with NOCl to give ethene, nitrous oxide and hydrogen chloride.
Industrial applications
NOCl and cyclohexane react photochemically to give cyclohexanone oxime hydrochloride. This process exploits the tendency of NOCl to undergo photodissociation into NO and Cl radicals. The oxide is converted to caprolactam, a precursor to Nylon-6.[2]
Safety
Nitrosyl chloride is very toxic and irritating to the lungs, eyes, and skin. Use safety mask while working with this chemical.
References
- ↑ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- ↑ 2.0 2.1 Josef Ritz, Hugo Fuchs, Heinz Kieczka, William C. Moran "Caprolactam" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. doi:10.1002/14356007.a05_031
- ↑ J. R. Morton, H. W. Wilcox "Nitrosyl Chloride" Inorganic Syntheses 1953, vol. 48-52. doi:10.1002/9780470132357.ch16
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ B. F. G. Johnson, K. H. Al-Obadi "Dihalogenodinitrosylmolybdenum and Dihalogenodinitrosyltungsten" Inorg. Synth. 1970, vol. 12, pp. 264–266. doi:10.1002/9780470132432.ch47
- ↑ Lua error in package.lua at line 80: module 'strict' not found.; Lua error in package.lua at line 80: module 'strict' not found.
- ↑ A. M. van Leusen and J. Strating "p-Tolylsulfonyldiazomethane" Org. Synth. 1977, vol. 57, 95. doi:10.15227/orgsyn.057.0095
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