| 초록 |
Glycerol carbonate (GC) can be synthesized under various catalysts by reaction routes homogeneous and heterogeneous. In this research, the Zn/Al mixed oxide (ZnAlO) catalysts (containing ZnO and ZnAl2O4 phases) were prepared by different methods: physical mixing of separated ZnO and ZnAl2O4 (p-ZnAlO), citric-template (ci-ZnAlO) and ZnO impregnated on ZnO and ZnAl2O4. These catalysts were experimented for the synthesis of glycerol carbonate from glycerol and urea at 140oC under vacuum condition (3kPa) to remove ammonia by-product in different reaction time. Reaction results are checked by GC-FID using internal standard method (tetraethylene glycol). XRD, XPS and FT-IR analysis of liquid products, fresh catalysts and spent catalysts are used to investigate the change of crystalline phase (ZnO, ZnAl2O4), the change of Zn’s electronic state and the functional groups (NCO, glycerol carbonate). At the 1hr reaction time, the i-ZnAlO catalyst gave the lowest GC yield. However, at the 3hr reaction time, the p-ZnAlO showed the lowest GC yield and GC selectivity. In both of case, ci-ZnAlO had the best reaction result. |
