Oxidação do glicerol com íons prata em baixas temperaturas

Abstract

Glycerol is a highly functional compound that has three hydroxyl groups in its structure, which is why in its oxidation process many high value-added products can be formed. The main objective of this work was to perform the catalytic oxidation of glycerol at low temperatures through homogeneous catalysis. The process, carried out in basic catalysis and aqueous solution, had as its oxidizing agent the silver ions. It was studied how the variation of the initial concentrations of the reactants, the pH and the temperature influence in the conversion rate of the glycerol in the products formed and in the selectivity to those products. This conversion rate and selectivity were calculated by Gas Chromatography; the identification of the products of catalytic oxidation of glycerol was made by High Performance Liquid Chromatography; and by means of Inductively Coupled Plasma Optical Emission Spectrometry, the consumption percentage of silver ions to metal silver was calculated. For this analysis, the results indicate that nine of the seventeen samples obtained consumption percentages above 90%, which guaranteed a significant withdrawal of these ions from the medium. Some results of Gas Chromatography point to an inversely proportional relation between the conversion rate of glycerol in its oxidation products and the selectivity to these products. It was observed that in three samples, which had the low glycerol initial concentration, the conversion rate was 100%, thus confirming that, in high quantity, glycerol inhibits its own oxidation process. The identification of the products showed mesoxalic acid as the major product of this study, with selectivity above 84% for all samples.