KINETICS OF WET AIR OXIDATION OF PHENOL

Aqueous solutions of phenol were oxidized in a batch reactor at temper atures between 150 and 300 degrees C and pressures from 100 to 200 bar . The initial phenol concentrations were between 460 and 1650 ppm and the initial oxygen concentration was always above 800% excess. The oxi dation experiments covered essentially the entire range of phenol conv ersions and included all temperature ranges studied by previous worker s. The reduction of COD during oxidation was also measured. Furthermor e, pyrolysis experiments were carried out to verify that phenol is not degraded by this mechanism in the conditions studied. Due to disagree ment in the previous published data about the activation energy, an ef fort has been made to obtain reliable kinetic data, assuring great oxy gen excess and minimum disturbance in the sampling procedure. The oxid ation reaction was found to be pseudo-first order with respect to phen ol, with an activation energy of 34.4 kJ mol(-1). The influence of pre ssure and temperature on the induction time was also studied. (C) 1997 Elsevier Science S.A.