Thermal oxidation of polypropylene catalyzed by manganese oxide aerogel in oxygen-enriched supercritical carbon dioxide

[Display omitted] •Thermal oxidation of polypropylene is efficient in the presence of compressed O2.•Supercritical CO2 enhances the thermal oxidation of polypropylene.•Manganese oxide as a catalyst promotes selective thermal oxidation of polypropylene.•Mix of acids and acetone are the main products of the described process. A new approach to the thermal oxidation of polypropylene in oxygen-enriched supercritical carbon dioxide is presented. Several parameters are revealed to affect the oxidation process, namely, the presence of supercritical carbon dioxide, the presence of Mn2O3 nanoparticles and oxygen to polypropylene mass ratio. It is demonstrated that the use of carbon dioxide enhances the oxidative process at lower oxygen content. Mn2O3 nanoparticles both increase the rate of the oxidation process and influence the product distribution. Gas chromatography-mass spectrometry reveals that acetone, acetic acid and formic acid are among the main products of the oxidation process. Furthermore, the obtained results show that, at a higher oxygen content, the use of manganese oxide aerogel as a catalyst promotes the selective oxidation of polypropylene, with acetic acid being the main liquid product of the process.