Synthesis, characterization, functionalization and tunable catalytic properties of bimetallic metal organic frameworks for glycerol oxidation

In this study, glycerol was oxidized to valuable chemicals which were dihydroxy acetone, glyceraldehyde, glyceric acid, formic acid, lactic acid and acetic acid by using the Zr based metal organic frameworks (MOF). Glycerol oxidation was performed using UiO-66 and UiO-66-NH2. In the synthesis of UiO-66 and UiO-66-NH2, terephtalic acid and amino terephtalic acid were used as ligand, respectively. The effect of amino groups and the effect of magnesium addition on the glycerol conversion and product selectivity were investigated for both MOFs. The synthesized MOFs were characterized using XRD, SEM, TGA and BET analysis. All the catalysts were found as thermally stabile according to TGA results. Crystallinity (XRD) of the catalyst were obtained similar to the UiO-66 in literature. High crystallinity of pure UiO-66 reduced the slightly after magnesium addition. According to SEM results, small particles were observed having a uniform distribution at homogeneity. Magnesium addition caused agglomeration. Glycerol oxidation reaction was carried out at 70ᵒC under atmospheric pressure for three hours. The most active catalyst was found as Mg0.3@UiO-66-NH2. The conversion of glycerol was calculated as 21.7 % and selectivity of formic acid, lactic acid and dihydroxy acetone was found as 42.2 %, 21.9 % and 20.3 %, respectively. The experimental design studies were also performed by using Anova software. The parametric study was investigated using Mg0.3@UiO-66-NH2 at different temperatures, catalyst loading and hydrogen peroxide/glycerol molar ratios.