|Jmol-3D images||Image 1|
|Molar mass||65.459 g mol−1|
|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)|
|Solubility in water||Reacts|
|Molecular shape||Dihedral, digonal|
|Hybridisation||sp2 at N|
|Dipole moment||1.90 D|
|261.68 J K-1 mol−1|
|Std enthalpy of
|51.71 kJ mol−1|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
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. It is a strong electrophile and oxidizing agent.
Structure and synthesis
Since nitrosyl chloride is chemically simple and stable at room temperature and below, it can be produced in many ways.
- HCl + NOHSO4 → H2SO4 + NOCl
- A more convenient laboratory method involves the (reversible) dehydration of nitrous acid by HCl
- HNO2 + 2HCl → H2O + NOCl
- 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:
- HNO3 + 3 HCl → Cl2 + 2 H2O + NOCl
- NOCl + SbCl5 → [NO]+[SbCl6]-
- ClNO + H2SO4 → ONHSO4 + HCl
- 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. 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:
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.
Nitrosyl chloride is very toxic and irritating to the lungs, eyes, and skin.
- Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- 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
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