Abstract
Dialkyl carbonates (DRCs) are valuable compounds widely used in the industry. The synthesis of DRC from CO(2) has attracted interest as an alternative to the current method, which uses phosgene. However, the reported approaches for DRC synthesis from CO(2) requires high-pressure and high-concentration CO(2), resulting in elevated costs associated with CO(2) purification and manufacturing facilities. In this report, we present an environmentally friendly method for producing DRC from low-concentration and low-pressure CO(2) via a dehydration condensation approach without the use of halogenated alkylating agents. This method involves the formation of monoalkyl carbonate [BASE-H][ROC(O)O] using a strong organic base and alcohols, tetraalkyl orthosilicates as dehydrating agents, and CeO(2) as the catalyst. Using the method, 39 and 30% of diethyl carbonate yields were accomplished with only 100 and 15 vol % CO(2) (CO(2)/N(2) = 15:85) gas bubbling at atmospheric pressure, even under reaction conditions with no large excess of either CO(2), alcohol, or dehydration agent.