Vidro borofosfato como substrato ativo para o crescimento de nanopartículas de óxido de cobre aplicado na hidroxilação do fenol por peróxido de hidrogênio

Abstract

Since a long time the glasses have a variety of applications, which vary according to their preparation and composition. Doped borophosphate glasses allow, through the bottom-up process, the formation of self-supported copper nanostructures. Borophosphate glasses were produced by the melt cooling method, with NaH2PO4/H3BO3 composition in molar ratio 2, addition of 10 mol% Al2O3 and doped with 6 mol% Cu+. Nanoparticles (NPs) of copper were obtained by annealing glass under an atmosphere of H2. Then, the heat treatment of this material in air led to the formation of NPs of copper oxide. The borophosphate glasses doped with 6% copper were characterized by Raman spectroscopy, X-Ray Diffraction, elemental composition by ICP-OES and differential thermal analysis. In addition to these tests were performed to reuse the catalyst. The borophosphate glass supported with copper nanoparticles was applied as heterogeneous catalysts for phenol hydroxylation by hydrogen peroxide. From the reaction parameters as reaction medium, temperature and reaction time, it sought to evaluate the influence of these on the conversion of phenol to dihydroxybenzenes. Results indicate a significant improvement in the conversions of phenol obtained at baseline, from 89.6% to 97.0%. Unexpectedly with the reuse of catalysts the glasses have proven more efficient in phenol hydroxylation. The results observed as to hydroxylation of phenol when carried out in aqueous media are higher than those reported in the literature and indicate the nanostructured hybrid vitreous materials as strong candidates to obtain catalysts on a commercial scale.