(CaO-MgO)@Fe3O4/C磁性固体碱催化甘油制备碳酸甘油酯

以活性炭、尿素和FeCl_3·6H_2O为原料得到Fe(OH)3,通过N2气氛还原得到磁核Fe_3O_4/C,随后将其置于CaCl_2与MgCl_2·6H2O溶液中超声分散,通过共沉淀法得到前驱体,焙烧制得磁性非均相固体碱催化剂(CaOMgO)@Fe_3O_4/C。对磁性非均相固体碱催化剂〔(CaO-MgO)@Fe_3O_4/C〕进行了磁滞回线、X射线衍射(XRD)、透射电镜(TEM)、CO_2-TPD及N_2的吸附-脱附(BET)测试。结果表明,CaO-MgO均匀地分散在磁核Fe_3O_4/C表面,催化剂在700℃有个强峰,具有较强的碱强度,磁化强度为23.8 emu/g,显示出较好的磁性。以碳酸二甲酯与甘油制备碳酸甘油酯作为探针反应,考察了(CaO-MgO)@Fe_3O_4/C催化剂的催化性能,得到在温度为85℃,n(碳酸二甲酯)∶n(甘油)=5∶1,催化剂用量为甘油质量的3%,反应时间为1 h的条件下,碳酸甘油酯的收率达到98.80%,甘油的转化率达到99.48%。催化剂重复使用6次后,碳酸甘油酯的收率为94.45%。

Catalytic Performance of magnetic (CaO-MgO)@Fe3O4/C solid base catalyst for Glycerol carbonate production from Glycerol

Magnetic heterogeneous catalyst ((CaO-MgO)@Fe3O4/C) was prepared for co-precipitation methods and magnetic core Fe3O4/C was reduced by activated carbon under N2 atmosphere. The reaction of glycerol carboante prepared using glycerol as a probe reaction, it is investigated that the catalytic performance of (CaO-MgO)@Fe3O4/C catalyst. With (CaO-MgO)@Fe3O4/C catalyst, glycerol carbonate yield reached 98.80% and glycerol conversion reached 95.20%. The (CaO-MgO)@Fe3O4/C catalyst was characterized by magnetic hysteresis loop, X-ray diffraction (XRD), CO2-TPD and transmission electron microscopy (TEM) and BET. The results indicated that Fe3O4/C was well wrapped (CaO-MgO); the (CaO-MgO)@Fe3O4/C catalyst exhibited good magnetic properties with high saturation magnetization (23.8emu/g) and the (CaO-MgO)@Fe3O4/C catalyst had strong basicity. The different reaction conditions on the yield of glycerol carbonate were investigated. The optimal reaction conditions were as follows: the reaction temperature was 85 oC and the reaction time was 1h, the molar ratio of DMC/glycerol was 5:1 and the catalyst dosage was 5.0wt. %. The catalyst still had steadily catalytic performance after 5 cycles with a high glycerol carbonate yield of 94.45%.