Catalytic wet oxidation of acetic acid using platinum on alumina monolith catalyst

The aqueous phase oxidation of acetic acid, used as a model compound for the treatment of controlled ecological life support system (CELSS) waste, was carried out in the monolith froth reactor which utilizes two-phase Row in the monolith channels. The catalytic oxidation of acetic acid was carried out over a Pt/Al2O3 catalyst at temperatures and pressures below the critical point of water. Multivariable non-linear regression 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 the 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] was 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 used, separating the effects of fluid mechanics from reactor residence time, the measured rate was dependent on the liquid Row rate. The results were interpreted in terms of detailed flow phenomenon that have previously been determined and reported. (C) 1998 Elsevier Science B.V.