Selective suppression of disproportionation reaction in solvent-less benzyl alcohol oxidation catalysed by supported Au-Pd nanoparticles

► Disproportionation of benzyl alcohol has been identified as the source of toluene formation in the aerobic oxidation of benzyl alcohol in a micro packed bed reactor (MPBR). ► This disproportionation reaction is sensitive to the reaction parameters like temperature and O2 concentration. ► Oxygen is found to promote the disproportionation, although it is not involved in the stoichiometry of the reaction. ► Quantification of oxidation and disproportionation reactions reveals that disproportionation is slightly more favoured in a MPBR than in a conventional glass stirred reactor. ► When MgO is used as the support instead of TiO2, disproportionation is reduced substantially and thus the toluene selectivity.