Carbonates

Carbonates from alkenes

The functional carbonate group ROC=(O)=OR' is a key component of many organic products. Important examples are cyclic carbonates, dimethyl carbonate, and diphenyl carbonate. Cyclic carbonates are important intermediate products. A relatively new route for the production of aromatic polycarbonates involves a transesterification cascade in which cyclic carbonates are converted into dimethyl carbonate and diphenyl carbonate and finally polycarbonate. In addition, cyclic carbonates have many applications as electrolytes in lithium ion batteries and solvents. Ethylene carbonate is used as a precursor for vinylene carbonate, another intermediate product in polymer production. In addition to the transesterification route, dimethyl carbonate is currently mainly produced via phosgenation or oxidative carbonylation of methanol (90 kt/a). Dimethyl carbonate has a wide range of potential applications in the fuel sector as well as in the chemical and electronics industries. Around half of global production currently goes into the manufacture of polycarbonates as a captive product (46 kt/a). Dimethyl carbonate is also used as a methylating agent, solvent in paints and coating agents, inks and electrolyte in lithium-ion batteries (23 kt/a). In addition to the transesterification route, diphenyl carbonate is currently produced by phosgenation of phenol or transesterification of dimethyl carbonate (250 kt/a). Diphenyl carbonate is an important intermediate in the production of aromatic polycarbonates.