Catalizzatori metallici supportati su resine reticolate per l'ossidazione selettiva dell'alcol benzilico con diossigeno

The oxidation of alcohols to the respective carbonyl and carboxylic groups play a fundamental role in the chemical industry. These compounds are in fact important chemical intermediates for the synthesis of drugs, vitamins, flavors and other fine chemical products starting from biomass or fossil by-products. Over the years, the rules for respecting of the environment have made the use of strong oxidants such as K2Cr2O7 and KMnO4 less sustainable for the large quantities of heavy salts as by-products. Infact these are reagents used in stoichiometric quantities. For this reason the study of catalytic methods that which involve more benign oxidants for the environment, in particular O2, has increased considerably. In recent years the study has focused on catalysts (both homogeneous and heterogeneous) containing metals such as palladium, gold, platinum, ruthenium and copper. Thanks to these it is possible to carry out the reaction of interest not only by using air or dioxygen as reagents, but also by obtaining only water as a by-product. Furthermore, even with rather mild conditions (pressures of a few bar and temperatures between 50 ° C and 100 ° C) it is possible that the reaction takes place, in an aqueous environment, in an organic environment or in the absence of a solvent with good conversion, yields and selectivity values. The substrate most used as a reference for the oxidation of aromatic alcohol is benzyl alcohol. This can lead to several oxidation products such as benzaldehyde, benzoic acid and benzyl benzoate. The quantities obtainable from the different products selected according to the reaction conditions and the type of catalyst used. Among the various products, benzaldehyde is a substance of extreme importance (second only to vanillin) in the food, cosmetics and perfume industries due to its intense aroma of almond and amaretto. In this Thesis work heterogeneus supported catalysts are used. The catalytic active materials are palladium and gold-palladium nanoparticles. The support is made of poly-divinilbenzene sulfonate (PDVBS) syntetized in solvo-thermal conditions. This polymer for its characteristics (such as permanent porosyty, pores diameter and re-swlling in several solvents) could be a very good candidate material to be used as support. The purpose of this Thesis work is to test the effectiveness of some mono and bimetallic catalysts supported on PDVBS and other functionalized polymers for the selective oxidation reaction of benzyl alcohol to benzaldehyde with dioxygen