Nitrosyl chloride

Structural formula
General
Surname	Nitrosyl chloride
other names	Nitrogen oxychloride Nitrosonium chloride
Molecular formula	NOCl
Brief description	reddish brown gas
External identifiers / databases
CAS number 2696-92-6 EC number 220-273-1 ECHA InfoCard 100.018.430 PubChem 17601 Wikidata Q419266
properties
Molar mass	65.46 g mol −1
Physical state	gaseous
density	2.98 kg m −3 (0 ° C)
Melting point	−61.5 ° C
boiling point	−5.55 ° C
Vapor pressure	271 k Pa (20 ° C)
solubility	rapid hydrolysis in water
safety instructions
GHS labeling of hazardous substances danger H and P phrases H: 270-280-330-314 EUH: 071 P: ?
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Nitrosyl chloride (NOCl) is the acid chloride of the nitrous acid HNO ₂ . It is a by-product of aqua regia . The resulting chlorine radicals are able to oxidize the precious metals gold and platinum to tetrachloroauric acid or hexachloridoplatinic acid.

Manufacturing

In aqua regia , a mixture of concentrated nitric acid and concentrated hydrochloric acid in a ratio of 1: 3, in addition to active chlorine, nitrosyl chloride is formed; these two species are responsible for the significantly increased aggressiveness of the freshly made mixture compared to the pure acids:

${\displaystyle \mathrm {HNO_{3}+3\ HCl\longrightarrow \ NOCl+2\ Cl+2\ H_{2}O} }$

For pure preparation in the laboratory, the reaction of fresh nitrosyl hydrogen sulfate with anhydrous sodium chloride is used :

${\displaystyle \mathrm {HSO_{3}ONO+NaCl\longrightarrow NOCl+NaHSO_{4}} }$

On the other hand, it can also be obtained by introducing nitrogen dioxide into a column of moist potassium chloride :

${\displaystyle \mathrm {KCl+2\ NO_{2}\longrightarrow KNO_{3}+NOCl} }$

Finally, chlorine can also be saturated with nitrogen monoxide at −50 ° C for production

${\displaystyle \mathrm {2\ NO+Cl_{2}\longrightarrow 2\ NOCl} }$

or sodium nitrite can be reacted with hydrogen chloride.

${\displaystyle \mathrm {NaNO_{2}+2\ HCl\longrightarrow NOCl+NaCl+H_{2}O} }$

In the industry is nitrosyl chloride by the oxidation of ammonia to nitrogen oxides and subsequent reaction with sulfuric acid to nitrosyl sulfuric acid reacted. This is converted into the actual nitrosyl chloride with hydrochloric acid.

${\displaystyle \mathrm {NH_{3}+Luft\longrightarrow Stickoxide} }$

${\displaystyle \mathrm {Stickoxide+H_{2}SO_{4}\longrightarrow NO^{+}HSO_{4}^{-}} }$

${\displaystyle \mathrm {NO^{+}HSO_{4}^{-}+HCl\longrightarrow NOCl} }$

properties

Nitrosyl chloride is a light-sensitive orange-yellow gas or yellow-red liquid. It reacts with water to form HCl, HNO ₃ , HNO ₂ and NO. It has a strong oxidizing, corrosive effect and, in liquid form, attacks the skin very severely.

Individual evidence

1. ↑ Entry on nitrosyl chloride. In: Römpp Online . Georg Thieme Verlag, accessed on June 20, 2014.
2. ↑ ^{a b c d e f} Entry on nitrosyl chloride in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
3. ↑ ^{a b c} G. Brauer (Ed.), Handbook of Preparative Inorganic Chemistry 2nd ed., Vol. 1, Academic Press 1963, pp. 511-2.