Catalytic wet oxidation of substituted phenols in the trickle bed reactor

Continual catalytic wet oxidation of phenol and its derivatives as a suitable chemical pretreatment before a biological treatment process was investigated. The evaluation of (i) the influence of amino‐, carboxy‐ and sulfo‐ phenol substituents on the course of the oxidation of hydroxyl‐aromatics, (ii) the catalytic ability of an active carbon, and (iii) the influence of reaction conditions, viz. temperature (120–160°C) and oxygen partial pressure (2–5 MPa) in the continuous trickle bed reactor, is presented. The active carbon type catalyst seems to be active enough for phenol oxidation, but it is not so effective for aromatic acids. The results of trickle bed operation were strongly influenced by hydrodynamics, viz. wetting efficiency. An insufficient catalyst wetting compensates for an effect of residence time in the bed and undesirable fluctuation of conversion appears at the low liquid velocities which are typical for waste water treatment processes. It is possible to achieve an optimal value of reactor productivity. © 1998 SCI