In this work, the oxidative pyrolysis of a reference tobacco and of two ingredients widely used as cigarette ingredients, i.e.: sorbitol and saccharose, as well as that of the mixtures of these materials has been studied by thermogravimetric analysis. The comparison of the results obtained with these corresponding to the pyrolysis processes under inert atmosphere shows the existence of reaction steps corresponding to pure pyrolysis or cracking processes and others corresponding to the combustion or other oxidative processes. The presence of mesoporous MCM-41 as catalyst seems to have more significant influence on the non-oxidative pyrolysis stages. Moreover, the pyrolysis processes taking place at temperatures lower than 400 degrees C seem to be practically independent of the oxidative character of the atmosphere used. (C) 2011 Elsevier B.V. All rights reserved.