Novel catalytic approaches to selective catalytic systhems for the direct synthesis of hydrogen peroxide

This Thesis is focused on the investigation of supported palladium catalysts for the direct synthesis of hydrogen peroxide, with particular attention to a novel material supported on a mesoporous ion-exchange resin. The main topic of this Thesis is the investigation of coordinating solvents, mainly acetonitrile and N,N-dimethylformamide, as novel corrosion-free promoters, to replace halides, commonly exploited as selectivity enhancers but leading to corrosion issues. The addition of coordinating solvents to the reaction solvent, i.e. methanol, remarkably increases not only the selectivity but also the production of hydrogen peroxide. This effect can be obtained only for catalysts supported on ion-exchange materials, suggesting that the key of the promotion effect is in the formation of Pd(II) complexes and their subsequent interaction with the support. This phenomenon is described in details and defined by using a semi-batch eactor working under very mild condition. Finally, preliminary investigations have been performed to make possible the exploitation of the most promising catalysts in an experimental setup suitable for the industrial application, such as a continuous flow reactor.