核桃果皮基磁性固体酸催化剂的制备及其催化性能研究

采用自底向上策略，利用农业废弃物核桃青果皮制备了磁性碳质固体酸催化剂，并对其进行了BET、XRD、SEM、IR和TGA等表征分析.结果表明，合成的磁性固体酸催化剂结构蓬松，比表面积大，具有良好的热稳定性.催化剂MPCs-0.2-SO₃H在生物柴油的合成中具有良好的催化活性.当醇油比为30，催化剂加入量为油酸质量的7%，80℃反应8 h酯化率达到74.2%，比商用Amberlyst-15催化剂的酯化率高近20%，最高含水量可达油酸质量的4%，重复使用3次后仍具有较高的酯化率，不仅实现了废弃物的资源化，而且得到的催化剂磁性易分离，在生物柴油的合成中具有巨大的应用潜能.

Preparation of magnetic solid acid catalyst from walnut peel and its catalytic activity in synthesis of biodiesel

Considering the bottom-up strategy, the magnetic carbonaceous solid acid catalyst was prepared by walnut green peel which was deemed to be an agricultural waste, meanwhile it was analyzed by BET, XRD, SEM, IR and TGA. The obtained results showed that synthesized magnetic solid acid catalyst has fluffy structure, high specific surface area and favorable thermal-stability. The catalyst of MPCs-0.2-SO₃H has played an important role in the synthesis of biodiesel. In a situation where the molar ratio of ethanol to oleic acid is 30, the dosage of magnetic solid acid catalyst is 7% oleic acid weight, the esterification rate can reach 74.2% after 8 h reaction at 80℃,which is superior to commercial Amberlyst-15of nearly 20%. Moreover, it still has high esterification rate after repeated use 3times, high water resistance of 4% weight of oleic acid. Therefore, walnut peel had been reused and synthesized magnetic catalyst, which was easy to be separated and demonstrated a prominent application potential in the preparation of biodiesel.