d-Glucose oxidation with H2O2 on an Au/Al2O3 catalyst
The oxidation of d-glucose to sodium d-gluconate with H2O2 has been investigated using an industrially relevant 0.3% Au/Al2O3 catalyst. The selectivity surprisingly exceeded 99% at d-glucose conversions >99%. Furthermore, high catalyst activity of about 8300 mmol min−1 gAu−1 was obtained at mild reaction conditions (40 °C, pH 9) and atmospheric pressure. The concentration of dissolved oxygen was tracked for most experiments and showed that the effective oxidizing agent is formed by the decomposition of H2O2 on the gold catalyst. Investigations on the reaction kinetics showed an apparent activation energy of 48 kJ mol−1 and a reaction order for d-glucose of 0.5, which both correspond to the values reported for d-glucose oxidation with O2. In addition, the oxidation of d-maltose, as a model disaccharide, to sodium d-maltobionate with H2O2 was studied. The results show that H2O2 is a very interesting alternative oxidizing agent for the selective oxidation of d-maltose as well.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights▶ Oxidation of d-glucose to sodium d-gluconate with H2O2 on a 0.3% Au/Al2O3 catalyst. ▶ Selectivity exceeded 99%. ▶ High catalyst activity of about 8300 mmol min−1 gAu−1 at mild reaction conditions and atmospheric pressure. ▶ Effective oxidizing agent is formed by the decomposition of H2O2 on the gold catalyst. ▶ High catalyst activity and selectivity was obtained in oxidation of d-maltose.
Journal: Applied Catalysis B: Environmental - Volume 102, Issues 3–4, 22 February 2011, Pages 584–589