การเตรียมออกไซด์ผสมของแคลเซียม ซิงก์ และอะลูมิเนียมสำหรับเมทานอไลซิสของไตรกลีเซอไรด์ / วนิดา อินชนะ = Preparation of Ca, Zn and AI mixed oxides for methanolysis of triglycerides
The present thesis investigated preparation of mixed oxides of Ca, Zn and Al as heterogeneous catalyst for methanolysis of triglycerides. The catalysts were prepared by co-precipitation of aqueous solution of the mixed metal nitrates in the presence of NH₄OH and ((NH₄)₂CO₃) after which the mixed oxides were attained by calcination at various temperatures. On the other hand, Ca/ZnAl catalysts were synthesized via incipient-wetness impregnation of Ca(NO₃)₂ over the calcined ZnAl LDHs followed by the thermal treatment. The catalysts were characterized by X-ray fluorescence spectroscopy (XRF), powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric/differential thermal analysis (TG/DTA), scanning electron microscopy (SEM), CO2- pulse chemisorption analysis and N₂ adsorption-desorption measurement. The Ca/ZnAl-500 catalyst with the molar ratio of Ca to Zn of 0.75 that was calcined at 500°C for 2 h gave the highest content of methyl esters. The methanolysis of triolein and trilaurin at reaction temperature of 60°C, reaction time of 3 h, molar ratio of methanol to oil of 15 and amount of catalyst of 10 wt.% gave the highest content of methyl esters of 83.8 and 99.9 wt.%, respectively.
