Flow Photo-On-Demand Phosgenation Reactions with Chloroform

Oxidative photochemical conversion of CHCl3 to COCl2 occurred efficiently in the gas phase with a designed flow photoreaction system. Gram-scale phosgenation reactions for synthesizing chloroformates and carbonate esters, including polycarbonates, were facilitated with the semibatch and continuous flow reaction systems. Taking advantage of this photochemical reaction, which proceeds almost quantitatively in a short time without chemical reagents, catalysts, or solvents, we successfully demonstrated solvent-free continuous flow reactions including the photoconversion of CHCl3 to COCl2 and a base-catalyzed phosgenation reaction with N-methylimidazole or pyridine, whose HCl salts become ionic liquids.