固体碱SrO-La_2O_3催化大豆油合成生物柴油

Catalytic Transesterification of Soybean Oil to Biodiesel Fuel Using SrO-La_2 O_3 as Catalyst

采用共沉淀法制备了SrO-La_2O_3复合氧化物固体碱催化剂,用于催化大豆油与甲醇的酯交换反应,并考察了催化剂制备方法及制备条件对大豆油转化率的影响。结果表明,采用共沉淀法、以氨水为沉淀剂,催化剂中Sr与La摩尔比1.5:1,催化剂焙烧温度973 K条件下显示出固体碱催化剂的最佳催化活性和稳定性。考察了酯交换反应条件对大豆油转化率的影响,结果表明,在甲醇沸点温度下,醇油摩尔比15:1、催化剂用量占反应物总量3%、反应时间4 h的最佳条件下,大豆油转化率最高达92.63%。考察了SrO-La_2O_3固体碱催化剂重复使用性能,结果表明,当催化剂重复使用3次后,再用773 K温度活化2 h后,催化剂活性仍保持90%以上,经5次重复利用后大豆油转化率仍能保持在90%左右。

SrO - La2O3 solid base catalyst was prepared by coprecipitation. The catalyst was used in catalysis of transesterification of soybean oil with methanol. The effects of methods preparing catalyst and preparation conditions on the conversion of soybean oil were examined. The result showed the solid base catalyst had optimum catalytic activities and stability by coprecipitation using ammonia water as precipitator with the molar ratio of Sr to La 1.5：1 at catalyst calcining temperature of 973 K. The effects of transesterification conditions on the conversion of soybean oil were examined. The result showed the conversion could be up to 92.63 under the optimum conditions as follows： molar ratio of methanol to soybean oil 15： 1, dosage of catalyst 3 % （based on the total mass of reactants） ,reaction time 4 hours at the temperature of boiling point of methanol. The behaviors of SrO - La2O3 solid base catalyst after repeated use were examined. The result showed the catalytic activity could maintain over 90%. The conversion of soybean oil could keep about 90% after repeatedly using five times.