UiO-66-NH_2 for obtaining levulinic esters derived from biomass

Abstract

As a result of the massive exploitation of oil and its depletion, the study of alternative raw materials for organic reactions from biomass is a current research trend. In this context, the present work proposes obtaining methyl and ethyl levulinate by means of the catalytic reaction of esterification of levulinic acid as a platform molecule, with methanol and ethanol. The catalyst used is MOF UiO-66-NH2, consisting of zirconium as a metallic precursor and aminoterephthalic acid as an organic binding agent. A synthesis route with more favorable environmental and economic conditions is presented, using alternative solvents. The replacement of the traditional dimethylformamide (DMF), used in the solvothermal synthesis, by 50% v / v acetone was proposed. Furthermore, the syntheses were carried out with magnetic and ultrasonic stirring, seeking to improve the structural properties of the catalysts. To understand crystal structure, morphology, and porosity, the materials were analyzed by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, X-ray photoelectron spectroscopy, microwave plasma atomic emission spectroscopy, acidity measurement and N2 adsorption. The progress of the catalytic reaction was followed by gas chromatography and mass spectroscopy. Among the synthesized materials, the one with the highest activity was the one obtained with 100% DMF using ultrasound synthesis. The conversion was 63,57% for methyl levulinate and 38,69% for ethyl levulinate.