The Application of Copper-Gold Catalysts in the Selective Oxidation of Glycerol at Acid and Basic Conditions

Abstract

The crude glycerol is produced during the transesterification of animal fats and vegetable oils, but it is a by-product of this process. Currently, its elimination is a problem in the chemical industry. The main goal of this work was the preparation, characterization and application of mesoporous cerium-zirconium oxide as supports for copper and gold species and the comparison of selected factors on the properties of catalysts in glycerol oxidation in the liquid phase. The samples were characterized using adsorption and desorption of nitrogen, XRD, UV-vis, XPS, TEM, SEM, and STEM-EDXS. The obtained results of glycerol oxidation show that the bimetallic copper-gold catalysts are more active and selective to glyceric acid in this reaction than analogous monometallic gold catalysts. Additionally, bimetallic catalysts are also characterized by the catalytic stability, and their application leads to the increase of selectivity to glyceric acid during their reusing in glycerol oxidation in alkali media. In this work, the influence of selected factors, e.g., oxygen source and its pressure, solution pH, and base content on the catalytic activity of bimetallic catalysts is discussed.