Synthesis of Ethyl Methyl Carbonate: Past, Present, and Future

Ethyl methyl carbonate (EMC) is the simplest asymmetric organic carbonate, with properties between dimethyl (DMC) and diethyl (DEC) carbonate, considered a unique green liquid organic compound for lithium batteries (electrolyte) and gasoline blending (octane enhancer additive), among other uses. In accordance, the chemical production of EMC is expected to increase during the coming years. However, this is not a trivial challenge since the price of EMC, due to its asymmetric structure, can be much higher than the symmetric counterpart DMC (although cheaper than DEC). This review shows the different synthetic approaches reported to date to manufacture EMC, from the old‐fashioned phosgenation reaction to modern catalytic procedures. The XXI century chemistry not only requires efficient but also sustainable processes, and these aspects, together with the different catalytic materials and reaction mechanisms reported for the synthesis of EMC, will be commented here. We present both academic research and patenting landscape, to compare and match the open advances with the protected technology. The final aim of this review is to show a complete picture of how EMC has been, is, and could be synthesized in the near future, collecting the available options and suggesting future directions to follow.