Nitrosyl chloride
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Nitrosyl chloride
| Nitrosyl chloride | |
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Nitrosyl chloride[citation needed] |
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Nitrooyl chloride[citation needed] |
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Other names
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| Identifiers | |
| CAS number | 2696-92-6  |
| PubChem | 17601 |
| ChemSpider | 16641 |
| EC number | 220-273-1 |
| UN number | 1069 |
| MeSH | nitrosyl+chloride |
| RTECS number | QZ7883000 |
| Jmol-3D images | Image 1 |
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| Properties | |
| Molecular formula | NOCl |
| Molar mass | 65.459 g mol−1 |
| Appearance | Yellow gas |
| Density | 2.872 mg mL−1 |
| Melting point |
-59.4 °C, 214 K, -75 °F |
| Boiling point |
-5.55 °C, 268 K, 22 °F |
| Solubility in water | Reacts |
| Structure | |
| Molecular shape | Dihedral, digonal |
| Hybridisation | sp2 at N |
| Dipole moment | 1.90 D |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
51.71 kJ mol−1 |
| Standard molar entropy S |
261.68 kJ mol−1 |
| Hazards | |
| MSDS | inchem.org |
| NFPA 704 |
 0
3
1
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| Related compounds | |
| Related compounds | |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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| Infobox references | |
Nitrosyl chloride is the chemical compound 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. The related nitrosyl halides nitrosyl fluoride, NOF, and nitrosyl bromide, NOBr, are also known.
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Contents
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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
As a simple, stable molecule, NOCl can be prepared in many ways. NOCl forms by the direct combination of chlorine and nitric oxide; this reaction reverses above 100 °C. Alternatively, nitrosylsulfuric acid and HCl also affords the compound:
- HCl + NOHSO4 → NOCl + H2SO4
This method is used industrially.[2] A more convenient laboratory method involves the (reversible) dehydration of nitrous acid by HCl[3]
Michael Faraday prepared nitrosyl chloride by reacting palladium with aqua regia:
- Pd + HNO3 + 3 HCl → PdCl2 + ClNO + 2 H2O
Another method of producing nitrosyl chloride is by direct union of the elements at 400 °C:
- N2 + O2 + Cl2 → 2 ClNO
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]+[SbCl5]-
In a related reaction, sulfuric acid gives nitrosylsulfuric acid, the mixed acid anhydride of nitrous and sulfuric acid:
- ClNO + H2SO4 → ONHSO4 + HCl
NOCl react with silver thiocyanate to give silver chloride and the pseudohalogen nitrosyl thiocyanate:
- ClNO + AgSCN → AgCl + ONSCN
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.[6] The initial addition of NOCl follows the Markovnikov rule. Ketenes also add NOCl, giving nitrosyl derivatives:
- CH2C=C=O + NOCl → ONCH2C(O)Cl
Propylene oxide also undergoes electrophilic addition with NOCl to give an α-chloro-nitritoakyl derivative:
At ambient temperatures, NOCl converts 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 a Cl radicals. The oxide is converted to caprolactam, a precursor to Nylon-6.[2]
Safety
NOCl is very toxic and irritating to the lungs, eyes, and skin.
References
- ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- ^ a b 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
- ^ L. J. Beckham, W. A. Fessler, M. A. Kise (1951). "Nitrosyl Chloride". Chemical Reviews 48 (3): 319–396. doi:10.1021/cr60151a001.
- ^ Edmund Davy (1830 - 1837). Abstracts of the Papers Printed in the Philosophical Transactions of the Royal Society of London, Vol. 3.. JSTOR. pp. 27–29. JSTOR 110250.
- ^ Ohno, M,; Naruse, N.; Terasawa, I. (1973), "7-cyanoheptanal", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv5p0266; Coll. Vol. 5: 266
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