Formation and reaction of diazonium salts in a CO2/H2O system

The formation of diazonium salts from the corresponding primary aromatic amines and their reaction with potassium iodide to give the corresponding aryl iodide have been performed in a CO2/H2O solvent system. The weak acidity of this system (pH about 3) allowed the formation of triazenes as an intermediate via a reversible reaction. Furthermore, several aryl iodides have been synthesised with high purity. Their isolation was achieved by venting CO2, without the utilization of organic solvents.