Tailorable Aqueous-Media Synthesis of Heterogeneous Copper Nanoparticles Hybrids and Application in Selective Oxidation of Benzene

Novel heterogeneous nanocatalysts has been synthesized in aqueous media at multimilligram scale for highly selective direct oxidation of benzene to phenol in aqueous media. The synthesis of a novel biohybrids containing copper nanoparticles (CuNPs) by an efficient and green technology have been described. The methodology involves the combination of an enzyme and a copper salt in aqueous media at room temperature. It was possible to control the copper species and nanoparticle size depending on the experimental conditions, e.g. pH, reducing step, amount of enzyme, obtaining novel heterogeneous nanobiohybrids containing exclusively Cu (0)NPs, Cu2O (Cu(i)) NPs or very crystalline Cu3(PO4)2 (Cu (ii)) NPs. Very small dispersed copper nanoparticles were formed in all cases (from 3 to 15 nm). These novel CuNPs biohybrids were evaluated as catalyst in the selective oxidation of benzene to phenol in water at 30ºC using hydrogen peroxide as oxidant, obtaining excellent yields and selectivity of phenol (>80% yield, >95% selectivity).