Abstract: Using poplar sawdust as a template, CaMg_xO_x+1 catalyst was obtained by impregnating aspen sawdust with a mixed aqueous solution of calcium and magnesium acetate, drying and calcination, and then used in the transesterification of castor oil and methanol, and the catalyst activity was evaluated based on the conversion rate of castor oil. The influence of catalyst preparation conditions on the activity of the catalyst was investigated by single factor experiments. The optimal conditions for preparing CaMg_xO_x+1 catalyst were as follows:a Ca/Mg molar ratio of 1:5, a calcination temperature of 900 ℃ and a calcination time of 7 h. The catalysts and their precursors were analyzed by thermogravimetric (TG), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the mass of the catalyst precursor decreased with the increase of the calcination temperature over 700 ℃, while the mass of catalyst precursor hardly changed with temperature when the temperature exceeded 900 ℃. The CaMg_xO_x+1 catalyst basically retained the crystal structure of the template poplar sawdust, with a large amount of amorphous or microcrystalline substances such as MgO, CaO or their complexes, and a small amount of crystalline substances such as MgO.

Key words: template, poplar sawdust, catalyst, castor oil, methanol, alcoholysis reaction