Preparation, characterization and oil alcoholysis activity of CaO/Co-Al-O solid base.

Ca O/Co- Al- O solid base catalyst was prepared using coprecipitation,impregnation and calcination methods. The effects of preparation conditions on the activity of Ca O/Co- Al- O solid base in oil alcoholysis were investigated by orthogonal experiment. The optimal preparation conditions were obtained as follows: molar ratio of Co to Al 3∶ 1,forward addition,mass fraction of Ca( Ac)2impregnation solution 0. 25,calcination temperature 700 ℃ and calcination time 6 h. When reaction temperature was65 ℃,reaction time was 3 h,molar ratio of methanol to castor oil was 9∶ 1,mass ratio of catalyst to castor oil was 0. 04∶ 1 and stirring speed was 400 r/min,the conversion rate of castor oil reached 94. 74% in the presence of the Ca O/Co- Al- O catalyst prepared under the optimal conditions. The catalyst and its precursor were characterized using techniques of TG- DTA,FT- IR,BET and XRD. The results indicated that Ca( Ac)2/ Co- Al hydrotalcite had three weight loss steps in the TG curve,respectively appearing at 100- 200 ℃,200- 300 ℃ and 680- 730 ℃; BET surface area,BJH desorption accumulative pore volume and BJH desorption average pore radius of Ca O/Co- Al- O solid base catalyst were 42. 7m2/ g,0. 29 cm3/ g and 11. 4 nm respectively; the active component Ca O in the solid base was highly dispersed on the surface of Co Al2O4 and Co3O4.