二酸化炭素を原料とする炭酸エステル類の触媒的合成

抄録

Organic carbonates such as dimethyl carbonate (DMC) and ethylene carbonate (EC) are useful intermediates for manufacturing polycarbonates through a non-phosgene process. In addition, organic carbonates are employed as electrolyte solvents in lithium ion batteries and are widely used as aprotic polar solvents. We wish to report our recent works concerning new synthetic procedures for linear and cyclic organic carbonates starting from carbon dioxide. The first methodology is dehydrative condensation of methanol with carbon dioxide. The keys for obtaining high conversion and selectivities are a) development of easily recyclable dehydrating agents; i.e. dimethyl acetals and b) addition of a small amount of acid cocatalysts; i.e. Ph₂NH₂(OTf). The second methodology is the cyclization of the oxiranes with carbon dioxide resulting in cyclic carbonates. The cyclization is thermodynamically favorable and continuous flow processes are demonstrated based on immobilized catalysts.