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How do chlorine and carbon monoxide form phosgene?

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A labeled diagram of the chlorine element from the periodic table shows its atomic number 17, symbol Cl, electron configuration, and atomic weight range. The box is shaded green to indicate chlorine is a halogen, with icons for orthorhombic crystal structure, gas state at room temperature, and strong acidity. A key explains the icons and colors used. — chlorine Properties of chlorine.

Phosgene, also known as carbonyl chloride ( $C O C l_{2}$ ), is manufactured through the chemical reaction of carbon monoxide and chlorine in the presence of a catalyst.12

The chemical equation for this synthesis is:
$C O + C l_{2} \to C O C l_{2}$

This reaction is industrially significant for the production of isocyanates and polyurethanes, as well as for use in metallurgy to transform certain oxides into chlorides. Because phosgene is a highly toxic gas that causes severe lung injury, it is essential to handle these substances with extreme caution and adhere to strict safety protocols in any industrial or laboratory setting.21