CO₂ valorization through methyl N-phenylcarbamate synthesis

Methyl N-phenylcarbamate (MPC) is an important intermediate for the synthesis of diphenylmethane diisocyanate (MDI), and its preparation using CO₂ or its equivalents/derivatives as carbon source represents a green and sustainable manner for fine chemicals synthesis. This review will highlight the development of MPC synthetic methods from the viewpoint of chemical fixation of CO₂. The contents mainly include the introduction of MPC synthesis through CO₂ equivalents (urea or phenyl urea) alcoholysis, dimethyl carbonate (DMC) aminolysis, and the coupling of DMC and diphenyl urea. Furthermore, one-pot synthesis of carbamates/MPC from aliphatic amines/aniline, CO₂ and alcohols is highlighted which represents one of the most promising schemes in direct CO₂ utilization. What is more, the reaction mechanisms and selection of catalysts are also discussed in detail. The advances will provide important theories on further improving the efficiency of green catalysis and sustainable chemical processes.