Sílica para conversão catalítica de glicerina residual da produção de biodiesel: um método sustentável para obter ácido fórmico

Abstract

A metal-free synthetic silica (Syntehtic SiO2) with high porosity (specific area of 1489 m2g-1) was used in the conversion of residual glycerin from the production of biodiesel supplied by Petrobras. The reactions are carried out using reactors operating in continuous flow and batch. The material showed a high selectivity to formic acid (65% approximately in continuous flow and 45% in batch). Interestingly, for the good conversion and high selectivity for the oxidative cleavage product (formic acid) there was no need for the use of supported metals as in the other works of the literature. The surface defects in the synthetic SiO2 generated Lewis acidity (identified by pyridine adsorption experiments), which in turn could activate the hydrogen peroxide that was used with oxidizing agent. The data presented in this work suggests, unprecedentedly, that these acid sites decompose the H2O2 generating active species of oxygen in the surface of the catalyst.