Novel synthetic pathway for the production of phosgene

Chloride ions are efficient catalysts for the synthesis of phosgene from carbon monoxide and elemental chlorine at room temperature and atmospheric pressure. Control experiments rule out a radical mechanism and highlight the role of triethylmethylammonium trichloride, [NEt₃Me][Cl₃], as active species. In the catalytic reaction, commercially available [NEt₃Me]Cl reacts with Cl₂ to form [NEt₃Me][Cl₃], enabling the insertion of CO into an activated Cl─Cl bond with a calculated energy barrier of 56.9 to 77.6 kJ mol⁻¹. As [NEt₃Me]Cl is also a useful chlorine storage medium, it could serve as a catalyst for phosgene production and as chlorine storage in a combined industrial process.