In this work the catalytic performance of an alumina supported manganese oxide catalyst in ethanol, ethyl acetate, toluene and mixtures of them was studied. The reactivity of each VOC investigated increased in the following order: ethanol > ethyl acetate > toluene. Toluene affects acetaldehyde yields, favoring partial combustion of ethanol and ethyl acetate. There is a competition for the adsorption sites between ethanol and ethyl acetate because both are polar molecules. Mixture effect decreases when the conversion temperature range of each component in the mixture is different, as in the case of ethanol-toluene and ethyl acetate-toluene mixture, consequently, the total conversion temperature is determined by the temperature at which the most difficult molecule is oxidized, in this case toluene. (C) 2009 Elsevier B.V. All rights reserved.