Palladium-catalyzed reductive carbonylation of nitrobenzene for producing phenyl isocyanate

Abstract

Direct reductive carbonylation of nitrobenzene to phenyl isocyanate with carbon monoxide was performed using various types of palladium catalysts together with many types of N-donor ligands. The effect of reaction time, pressure, temperature, ligand amount, and molar ratio to establish the optimized conditions was also investigated. With this, we were able to achieve up to 100% conversion and 63.5% yield with PdCl2 and alkylimidazole system (1:3) within 2 h at 220 °C and 1400 psi of CO in toluene.