Glycerol oxidation by Silica supported gold catalysts

Abstract

This thesis has studied the preparation, characterization and performance test of various supported gold catalysts. The preparation has been focused on immobilization of gold on amido-amidoxime functionalized SiO2 and mesoporous materials, i.e. MCM-41 and SBA-15. The conventional impregnation method using HCOH as a reducing agent was applied for comparison. The catalytic performance of supported nanogold was investigated in the liquid phase oxidation of glycerol using molecular oxygen at atmospheric pressure. Amido-SiO2, Amido-MCM-41 and Amido-SBA-15 supported Au catalysts were successfully prepared through the pH-controlling immobilization method, resulting in the high gold content and the formation of gold particles with nanosize. Controlling pH of reaction mixture by addition of a suitable amount of NaOH solution improved the glycerol conversion. The pH was optimized at 11 since it maintained the glyceric acid selectivity at a high value. The glycerol conversion was slightly enhanced by increasing the flow rate of O2. It seems that this influence affected the reaction at much less extent than the pH of reaction solution.