Selective partial oxidation in supercritical water: the continuous generation of terephthalic acid from para-xylene in high yield

The continuous selective oxidation of p-xylene (p-X) by O-2 (generated by thermal decomposition of aqueous H2O2) catalyzed by MnBr2 in supercritical H2O at ca. 400 degreesC is reported for the first time. The selectivity for terephthalic acid (TA) is > 90%. Compared to existing industrial processes, the reaction has the potential for a significant increase in energy efficiency and a substantial reduction in waste. This reaction is significant because the presence of H2O lowers the catalytic activity of MnBr2 in the conventional route to TA via oxidation of p-X in CH3COOH.