An Innovative Microwave Process for Nanocatalyst Synthesis

The development of greener chemical processes is becoming more and more important because this approach moves towards sustainable methods and products, minimizing pollution and risks for human health and environment. In these perspectives, microwaves seem to fulfil these requirements; in this context, we have tested a novel method both for the synthesis of nanocatalysts and for thermal activation of catalytic reactions. Until now, microwave chemistry has been generally performed inside a closed metal cavity, i.e. a microwave oven, but this approach presents relevant drawbacks, in particular for large scale application. Recently, we have proposed a new, cheap, sustainable process for large scale preparation of nanocatalysts, overcoming the disadvantages of the current synthesis methods. This novel method has been successfully adopted for the preparation in situ of ruthenium, palladium and silver nanoparticles as colloids or on different supports. Our procedure is safe and cheap, enabling to obtain the utmost efficiency and control also for industrial application. The obtained nanocatalysts present small average diameters, good morphology and very narrow sizes distribution with an absolute reproducibility. The ruthenium nanocatalysts were tested in the selective hydrogenation of phenol to cyclohexanone and palladium nanocatalysts were tested in the selective hydrogenation of cinnamaldehyde to hydrocinnamaldehyde, and we obtained good performances in both reactions.