Partial oxidation of benzene catalyzed by vanadium chloride in novel reaction–extraction–regeneration system

This paper investigates the liquid-phase partial oxidation of benzene to phenol in a novel system consisting of reactor, extractor and regenerator. Since vanadium catalyst (V3+) is oxidized in the reactor and therefore deactivated, the regenerator with Pd or Pt catalyst and H2 feed is employed to regenerate the deactivated vanadium. The V4+ ion can be reduced to V3+ and consequently the phenol production can be enhanced. Although the regenerator can regenerate vanadium catalyst and the reaction can proceed for over 100 h, some V4+ is still present. The feed position of benzene and catalyst solution have the influence on mixing condition in the reactor and interface area between benzene and catalyst solution. Counter current flow operation with the feeds of catalyst solution and benzene at the top and the bottom respectively shows the highest phenol production. The operating temperature of reactor, extractor and regenerator showed insignificant effect on phenol production rate.