Abstract:

Solid base catalysts used in the transesterification for biodiesel production can simplify the technological processes, especially the separation process of productsBy screening metal oxides, calcium oxide was found to be a potential catalyst for the transesterification of rapeseed oilImpregnating calcium acetate solution onto MgO carrier and calcining the impregnated sample obtained a CaO/MgO catalyst containing 165%(mass) of calcium oxide, which exhibited a high activity in the transesterification reactionBy using this catalyst, under the condition of 64.5℃, a methanol/oil molar ratio of 18∶1 and a catalyst dosage of 2%, oil conversion reached 92% in 3.5 h, which was close to the oil conversion using the traditional NaOHFurthermore, the solid catalysts obtained were characterized with XRD, AAS, XPS and CO2-TPDThe results showed that the basicity of the catalysts greatly affected their activitiesProperly selecting the carrier, precursor and Caloading could increase the strong basic sites, and therefore increase their catalytic activity.

Key words: 生物柴油, 固体碱催化剂, 钙催化剂

摘要：

固体碱催化剂用于酯交换反应制备生物柴油有易分离、流程简单的优点。通过金属氧化物活性筛选，发现氧化钙具有很好的酯交换反应活性。将乙酸钙溶液等体积浸渍负载于碱性载体MgO上，并煅烧得到了氧化钙负载量为16.5％(质量)的CaO/MgO混合氧化物催化剂，其在油脂甲醇酯交换反应制备生物柴油的过程中具有高的反应活性。在64.5℃、醇油比18∶1 、催化剂用量2%、反应3.5 h条件下，油脂转化率为92%，接近传统的液体强碱NaOH的催化能力。用XRD、AAS、XPS、CO2 -TPD等对制得的系列催化剂进行了表征，发现催化剂的碱强度对酯交换反应有着重要的影响。通过选择合适的载体、含钙前驱体和氧化钙负载量可以增加负载型氧化钙催化剂的强碱性位，提高催化剂的反应活性。

关键词: 生物柴油, 固体碱催化剂, 钙催化剂