Green Synthesis of Dimethyl Carbonate from CO2 and Methanol: New Strategies and Industrial Perspective

Dimethyl carbonate (DMC) is a commonly used and environmentally sustainable chemical compound and intermediate in a variety of industrial applications. To date, several large-scale industrial DMC synthesis routes have been developed, including methanol phosgenation, transesterification, and oxidative carbonylation of methanol. However, these manufacturing routes have several disadvantages, such as the use of hypertoxic phosgene as raw material, costly processing, and explosion risks. The most encouraging and ecofriendly path is the green production of DMC from CO2 and methanol. Various catalytic materials have been examined concerning their suitability for DMC synthesis. The issues of low yield and difficulty in tests have not been resolved fundamentally, which is caused by the inherent problems of the synthetic pathway and limitations imposed by thermodynamics. The search for more efficient production routes has driven the activation of CO2 via electro-assisted synthesis as well as membrane reactors, which can isolate products in real-time to maximize DMC yield. The green synthesis of dimethyl carbonate catalyzed by different catalysts including Zr/Ce/Cu-based nanocomposites, organometallic compounds, heteropoly acid, ionic liquid, metal-organic frameworks, etc, is discussed in detail. Further, the structure-activity relationships and insights into molecular activation and catalytic mechanisms, as well as the identification of active sites on catalysts are addressed.