Synthesis of dimethyl carbonate in supercritical carbon dioxide

The reactivity of carbon dioxide with methanol to form dimethyl carbonate was Studied in the presence of the n-butylmethoxytin compounds n-Bu3SnOCH3, n-Bu2Sn(OCH3)(2), and [n-Bu-2(CH3O)Sn](2)O. The reaction occurred under solventless conditions at 423 K and was produced by an increase in CO, pressure. This beneficial effect is primarily attributed to phase behavior. The mass transfer under liquid-vapor biphasic conditions was not limiting when the system reached the supercritical state for a CO, pressure higher than 16 MPa. Under these conditions, CO2 acted as a reactant and a solvent.