磁性固体超强酸的制备及催化合成乙酸异戊酯的研究

Study on preparation of magnetic solid super acid and catalytic synthesis of isoamyl acetate

采用共沉淀法制备SO42-/Fe3O4-Al2O3-ZrO2-Nd2O3磁性固体超强酸催化剂,应用于乙酸异戊酯的合成。利用XRD、IR、EDS、SEM等测试手段对催化剂结构进行了表征,结果表明,SO42-/Fe3O4-Al2O3-ZrO2-Nd2O3磁性固体超强酸中ZrO2以四方晶相(T相)稳定存在,SO42-与金属离子以桥式双配位结合;催化剂表面疏松多孔,具有很大的比表面积。将磁性固体超强酸催化剂应用于合成乙酸异戊酯的反应中,采用均匀设计实验,利用U11(1110)表,考察了各种因素对酯化率的影响,确定最佳合成工艺条件为:催化剂加入1.58 g,n(乙酸)∶n(异戊醇)=1∶1.8,反应时间为3.16 h,酯化率达98%以上。乙酸异戊酯产品结构经折光率、红外光谱进行了表征与确认。同时实验表明,SO42-/Fe3O4-Al2O3-ZrO2-Nd2O3磁性固体超强酸催化剂可多次重复使用,活化降低不大,是一种稳定性高、选择性好的新型环境友好的催化剂。

The SO4^2-/Fe304-Al2O3-ZrO2-Nd2O3 magnetic solid super acid catalyst was prepared by copre- cipitation, and was used in isoamyl acetate synthesis. The structure of the catalyst was confirmed by XRD, EDS, SEM, IR. The results show that in the SO4^2-/Fe3O4-Al2O3-ZrO2-NdzO3 magnetic solid super acid the ZrO2 is stable as tetra-gonal phase （T phase） ,SO4^2- and metalion coordinates as bridge two-way combination, the catalyst surface is porous, and specific surface area is great. The magnetic solid super acid cata- lyst was used in synthesis of isoamyl acetate. The influence on the esterification rate was investigated by U11 （ 11^10）table, the optimum synthesis conditions were as follows： catalyst 1.58 g, n（ acetic acid） ： n （isoamyl alcohol） = 1：1.8 ,the reaction time 3.16 h,the esterification rate more than 98%. The structure of products was characterized by refractive index and IR. It was also found that,SO4^2-/Fe3O4-Al2O3- ZrO2-Nd2O3 magnetic solid superacid catalyst can be reused and activation decreases slightly, and is a new type of catalyst, which is high-stability, good selectivity and environment-friendly.