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| Names | |
|---|---|
| IUPAC name Nitrosyl chloride[1] | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider |
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| ECHA InfoCard | 100.018.430 |
| EC Number |
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| E number | E919(glazing agents, ...) |
| MeSH | nitrosyl+chloride |
| RTECS number |
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| UNII | |
| 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 | |
Std molar entropy(S⦵298) | 261.68 J K−1 mol−1 |
Std enthalpy of formation(ΔfH⦵298) | 51.71 kJ mol−1 |
| Hazards | |
| NFPA 704 (fire diamond) | |
| Safety data sheet (SDS) | inchem.org |
| Related compounds | |
Related compounds | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Nitrosyl chloride is thechemical compound with the formula NOCl. It is a yellow gas that is commonly encountered as a component ofaqua regia, a mixture of 3 parts concentratedhydrochloric acid and 1 part of concentratednitric acid. It is a strongelectrophile andoxidizing agent. It is sometimes called Tilden's reagent, afterWilliam A. Tilden, who was the first to produce it as a pure compound.[2]
The molecule is bent. Adouble bond exists between N and O (distance = 1.16 Å) and a single bond between N and Cl (distance = 1.96 Å). The O=N–Cl angle is 113°.[3]
Nitrosyl chloride can be produced in many ways.
NOCl also arises from the combination of hydrochloric and nitric acids according to the following reaction:[7]
In nitric acid, NOCl is readily oxidized intonitrogen dioxide. The presence of NOCl in aqua regia was described byEdmund Davy in 1831.[8]
NOCl behaves as an electrophile and an oxidant in most of its reactions. Withhalide acceptors it givesnitrosonium salts, and synthesis ofnitrosonium tetrachloroferrate is typically performed in liquid NOCl:[9]
In a related reaction, sulfuric acid givesnitrosylsulfuric acid, the mixedacid anhydride of nitrous and sulfuric acid:
NOCl reacts with silver thiocyanate to givesilver chloride and thepseudohalogen nitrosyl thiocyanate:
Similarly, it reacts with silver cyanide to givenitrosyl cyanide.[10]
Nitrosyl chloride is used to preparemetal nitrosyl complexes. Withmolybdenum hexacarbonyl, NOCl gives the dinitrosyldichloride complex:[11]
It dissolves platinum:[12]
Aside from its role in the production of caprolactam, NOCl finds some other uses inorganic synthesis. It adds toalkenes to afford α-chlorooximes.[13] The addition of NOCl follows theMarkovnikov rule.Ketenes also add NOCl, giving nitrosyl derivatives:
Carbonyl compoundsenolize; and then NOCl attacks the nucleophilic end of the alkene to give a vicinal keto- or aldo-oxime.[9]
Epoxides react with NOCl to give an α-chloronitritoalkyl derivatives. In the case of propylene oxide, the addition proceeds with high regiochemistry:[14]
It converts amides toN-nitroso derivatives.[15] NOCl converts some cyclic amines to the alkenes. For example,aziridine reacts with NOCl to giveethene,nitrous oxide andhydrogen chloride.
NOCl andcyclohexane reactphotochemically to givecyclohexanone oxime hydrochloride. This process exploits the tendency of NOCl to undergophotodissociation into NO and Cl radicals. The cyclohexanone oxime is converted tocaprolactam, a precursor tonylon-6.[4][16]
Before the advent of modern spectroscopic methods for chemical analysis, informative chemical degradation and structure elucidation required the characterization of the individualcomponents of various extracts. Notably, the aforementioned introduction of nitrosyl chloride by Tilden in 1875, as a reagent for producing crystalline derivatives of terpenes, e.g. α-pinene from oil of turpentine allowed investigators to readily distinguish one terpene from another.:[17]
Nitrosyl chloride is very toxic and irritating to the lungs, eyes, and skin.
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