One-pot green synthesis of propylene oxide using in situ generated hydrogen peroxide in carbon dioxide

In the one-pot green synthesis of propylene oxide using in situ generated hydrogen peroxide, a propylene oxide yield of 23% with 82% selectivity was achieved over a ( 0.2% Pd + 0.02% Pt)/TS-1 catalyst by using compressed (supercritical or liquid) carbon dioxide as the solvent and small amounts of water and methanol as co-solvents. The addition of an inhibitor effectively suppressed a number of common side-reactions, including the hydrogenation of propylene, the hydrolysis of propylene oxide and the reaction between propylene oxide and methanol. This suppression effect is due to the interaction between the inhibitor and TS-1 leading to the neutralization of its surface acidity.