Catalytic synthesis of dialkyl carbonate from low pressure CO₂ and alcohols combined with acetonitrile hydration catalyzed by CeO₂

Dialkyl carbonates have attracted much attention from the viewpoint of sustainable chemistry because they are useful intermediates and solvents and can be synthesized from renewable resources. One promising synthesis method of the dialkyl carbonates is the reaction of CO₂ with the corresponding alcohols. Direct synthesis of diethyl carbonate and dipropyl carbonate from ethanol + CO₂ and 1-propanol + CO₂ was promoted remarkably by the combination of acetonitrile hydration. The yield based on CO₂ reached 42 and 33% for diethyl carbonate and dipropyl carbonate, respectively. All the reactions were catalyzed by CeO₂ as a heterogeneous catalyst. It is characteristic that the combination with in situ dehydration enabled the conversion of low pressure CO₂ to dialkyl carbonate.