Oxidation of benzene with N2O on ZSM-5 zeolite: A comparison of gas-phase and supercritical conditions.

The catalytic oxidation of benzene with nitrous oxide (N 2 O) over ZSM-5 zeolite has been carried out in a continuous-flow reactor under supercritical conditions and compared with the results of the gas-phase reaction. Aromatic substrates and nitrous oxide under the conditions of supercritical experiments (300–435 °C, 6.0–18.0 MPa) are both reagents and the supercritical medium. It has been established that the productivity of the supercritical oxidation of benzene into phenol significantly exceeds the productivity of the gas-phase process owing to the limited reversible deactivation of the catalyst under supercritical conditions and the in situ removal of the coke precursors by the dense reaction medium. In addition, it has been demonstrated that a successful in situ regeneration of the deactivated oxidation catalyst can be carried out during the transition from gas-phase reaction conditions to supercritical conditions in one experiment. [Display omitted] • ZSM-5 zeolite is a highly active and selective catalyst of benzene oxidation. • Benzene and nitrous oxide are both reagents and the supercritical medium. • Productivity of supercritical benzene oxidation greatly exceeds that of gas-phase oxidation. • Enhanced performance is due to dissolution and removal of coke precursors by the reaction supercritical medium. • Regeneration of deactivated catalyst has been carried out using supercritical conditions. [ABSTRACT FROM AUTHOR]