Catalyst precursor Mg - Al hydrotalcite was prepared by coprecipitation, and then Mg - Al complex oxides catalyst was prepared by high temperature calcination. Taking transesterification of castor seed oil with methanol as probe reaction and castor seed oil conversion rate as activity evaluation index, effects of catalyst preparation conditions on catalyst activity were investigated through orthogonal experiment. The optimal conditions were as follows; sodium carbonate dosage 7. 5% , calcination temperature 550 ℃ and calcination time 7 h. With Mg - Al complex oxides prepared under optimal conditions as catalyst , average castor seed oil conversion rate of the transesterification of castor seed oil with methanol was 96. 2% . Mg - Al hydrotalcite and Mg - Al complex oxides prepared under optimal conditions were characterized by TG - DTG, XRD, BET, SEM techniques. The results showed that Mg - Al hydrotalcite had two distinct weightlessness peaks at 230℃ and 420 ℃ ; Mg - Al complex oxides were similar to MgO in crystalline structure with BET specific surface area 211. 7 m2/g, BJH desorption cumulative pore volume (0. 85 - 150 nra) 0. 90 cm3 /g,BJH desorption average pore radius 9. 6 nm and honeycomb - shaped surface morphology.%采用共沉淀法制备了催化剂前体镁铝水滑石,再高温焙烧制得镁铝复合氧化物催化剂.以蓖麻油和甲醇酯交换反应为探针反应,以蓖麻油转化率为催化剂活性评价指标,采用正交实验考察了催化剂制备条件对催化剂活性的影响,结果表明:在碳酸钠用量7.5％、焙烧温度550℃、焙烧时间7h条件下,制得的镁铝复合氧化物催化剂用于蓖麻油和甲醇酯交换反应,得出蓖麻油转化率平均可达96.2％.采用TG-DTG、XRD、BET、SEM技术对优化条件下制得的镁铝水滑石及镁铝复合氧化物进行了表征,结果显示:镁铝水滑石在230℃和420℃时,有两个明显的失重峰；镁铝复合氧化物与氧化镁具有相似的晶相结构,其BET比表面积为211.7 m2/g,BJH脱附累积孔容(0.85～150 nm)为0.90 cm3/g,BJH脱附平均孔半径为9.6 nm,表面形貌呈蜂窝状.
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