| CaO/(Mg-Fe-O) solid base catalyst was prepared by coprecipitation,impregnation and calcination. Taking conversion rate of castor seed oil as evaluation index of catalyst activity, the effects of preparation conditions on the catalytic activity of CaO/(Mg-Fe-O) solid base in transesterification were investigated through orthogonal experiment. The optimal conditions were obtained as follows: molar ratio of Mg to Fe 3∶1, mass fraction of calcium acetate impregnation solution 15%, impregnation time 12 h, calcination temperature 800℃, calcination time 2 h. CaO/(Mg-Fe-O) solid base prepared under the optimal conditions was used as catalyst in the transesterification of castor seed oil and methanol, and the conversion rate of castor seed oil reached 94.74%. The catalyst and its precursor were characterized by TG-DTA,FTIR,BET and XRD.The results revealed that when the temperature exceeded 750℃, Ca(Ac)2/(Mg-Fe hydrotalcite) almost did not loss weight; compared with Ca(Ac)2/(Mg-Fe hydrotalcite), —OH and CO2-3 infrared absorption peaks of CaO/(Mg-Fe-O) solid base decreased significantly; CaO supported in mesoporous of the solid base catalyst CaO /(Mg-Fe-O) played the main catalytic role; CaO in the solid base was highly dispersed on the surface of MgFe2O4 and MgO in the form of amorphous or microcrystal. |
