CATALYTIC WET OXIDATION OF ACETIC-ACID USING PLATINUM ON ALUMINA MONOLITH CATALYST

The aqueous phase oxidation of acetic acid, used as a model compound f or the treatment of controlled ecological life support system (CELSS) waste, was carried out in the monolith froth reactor which utilizes tw o-phase Row in the monolith channels. The catalytic oxidation of aceti c acid was carried out over a Pt/Al2O3 catalyst at temperatures and pr essures below the critical point of water. Multivariable non-linear re gression of temperature-dependent data revealed a reaction order of 1. 22 +/- 0.54 and an activation energy of 89.8 +/- 13.4 kJ/mol. Since th e reaction order bracketed first-order kinetics, a pseudo-first-order rate constant of k(1)=10(5.713+/-2.0) exp[81.04 +/- 19.0 kJ/mol/RT] wa s obtained. This value is similar to values reported for the oxidation of acetic acid in other systems and is comparable to intrinsic values calculated for oxidation reactions. Although a recycle reactor was us ed, separating the effects of fluid mechanics from reactor residence t ime, the measured rate was dependent on the liquid Row rate. The resul ts were interpreted in terms of detailed flow phenomenon that have pre viously been determined and reported. (C) 1998 Elsevier Science B.V.