Nitrous
NITROSYL CHLORIDE
657
NITROSYL CHLORIDE
[2696-92-6] Formula: ClNO; MW 65.459 Structure: Cl—N=O. bent molecule, N—O bond distance 1.139Å and N—Cl bond distance 1.975Å Uses Nitrosyl chloride is an important component of aqua regia. It is an oxidizing agent in organic synthesis. It also is used as a catalyst. Physical Properties Yellow gas; heavier than air, density 2.3 (air=1); gas density 2.872 g/L; liquefies at –5.55°C; liquid density 1.273 g/mL; freezes at –59.4°C; critical temperature 167°C; reacts with water; soluble in fuming sulfuric acid. Thermochemical Properties ∆Ηƒ° ∆Gƒ° S° Cρ ∆Hvap 12.37 kcal/mol 15.81 kcal/mol 62.55 cal/degree mol 10.68 cal/degree mol 6.16 kcal/mol
Preparation Nitrosyl chloride can be prepared by the reaction of nitric oxide with chlorine: 2NO + Cl2 → 2ClNO Also, nitrosyl chloride is produced by the action of chlorine on sodium nitrate; or by the reaction of nitrosyl sulfuric acid with hydrochloric acid: NaNO3 + Cl2 → ClNO + NaClO2 ONHSO4 + HCl → ClNO + H2 SO4 Nitrosyl chloride also is obtained as a byproduct in the manufacture of potassium nitrate from potassium chloride and nitric acid: 3KCl + 4HNO3 → 3KNO3 + Cl2 + ClNO + 2H2O In the above preparative method, nitrosyl chloride must be separated from nitric acid; otherwise, in the presence of pure and excess nitric acid, it can decompose to nitrogen dioxide and chlorine: elevated temperature
658
NITROSYL CHLORIDE
2ClNO + HNO3 → 6NO2 + Cl2 +2H2O Also, nitrosyl chloride can be synthesized from its elements by heating nitrogen, oxygen and chlorine gas at 400°C: N2 + O2 + Cl2 → 2ClNO Faraday obtained nitrosyl chloride by dissolving palladium in a mixture of hydrochloric and nitric acids (Faraday, M. Trans. Roy. Soc. (London), Vol. 136, pp. 48, 1846): Pd + HNO3 + 3HCl → PdCl2 + ClNO + 2H2O Reactions Nitrosyl chloride undergoes addition reactions with many unsaturated organic compounds. It adds to olefinic double bond as follows: HC=CH— + Cl—N=O → ClCHCHNO For
657
NITROSYL CHLORIDE
[2696-92-6] Formula: ClNO; MW 65.459 Structure: Cl—N=O. bent molecule, N—O bond distance 1.139Å and N—Cl bond distance 1.975Å Uses Nitrosyl chloride is an important component of aqua regia. It is an oxidizing agent in organic synthesis. It also is used as a catalyst. Physical Properties Yellow gas; heavier than air, density 2.3 (air=1); gas density 2.872 g/L; liquefies at –5.55°C; liquid density 1.273 g/mL; freezes at –59.4°C; critical temperature 167°C; reacts with water; soluble in fuming sulfuric acid. Thermochemical Properties ∆Ηƒ° ∆Gƒ° S° Cρ ∆Hvap 12.37 kcal/mol 15.81 kcal/mol 62.55 cal/degree mol 10.68 cal/degree mol 6.16 kcal/mol
Preparation Nitrosyl chloride can be prepared by the reaction of nitric oxide with chlorine: 2NO + Cl2 → 2ClNO Also, nitrosyl chloride is produced by the action of chlorine on sodium nitrate; or by the reaction of nitrosyl sulfuric acid with hydrochloric acid: NaNO3 + Cl2 → ClNO + NaClO2 ONHSO4 + HCl → ClNO + H2 SO4 Nitrosyl chloride also is obtained as a byproduct in the manufacture of potassium nitrate from potassium chloride and nitric acid: 3KCl + 4HNO3 → 3KNO3 + Cl2 + ClNO + 2H2O In the above preparative method, nitrosyl chloride must be separated from nitric acid; otherwise, in the presence of pure and excess nitric acid, it can decompose to nitrogen dioxide and chlorine: elevated temperature
658
NITROSYL CHLORIDE
2ClNO + HNO3 → 6NO2 + Cl2 +2H2O Also, nitrosyl chloride can be synthesized from its elements by heating nitrogen, oxygen and chlorine gas at 400°C: N2 + O2 + Cl2 → 2ClNO Faraday obtained nitrosyl chloride by dissolving palladium in a mixture of hydrochloric and nitric acids (Faraday, M. Trans. Roy. Soc. (London), Vol. 136, pp. 48, 1846): Pd + HNO3 + 3HCl → PdCl2 + ClNO + 2H2O Reactions Nitrosyl chloride undergoes addition reactions with many unsaturated organic compounds. It adds to olefinic double bond as follows: HC=CH— + Cl—N=O → ClCHCHNO For