Photocatalytic oxidation of n-octanol in aerated supercritical CO2 on hydrophobic TiO2

Supercritical CO₂ (scCO₂) has been used as a reaction medium for the photocatalytic oxidative degradation of n-octanol on a partially desilanized hydrophobic suspension of TiO₂ as photocatalyst. Hydrophobic sites on the catalyst surface are necessary to maintain a sustained suspension, and hence surface-mediated interfacial electron exchange, in this non-polar medium. The reaction rates for photooxidative degradation, ultimately to complete mineralization, depend only weakly on temperature and pressure of the supercritical fluid near the critical point. Product distributions were monitored in situ by on-line gas chromatographic analysis, which provides a convenient and rapid method for comparisons and optimization of the reaction conditions.