SO_4~(2-)/TiO_2-M_xO_y固体超强酸的制备及其催化合成水杨酸异戊酯性能

合成了复合型固体超强酸SO_4~(2-)/TiO_2-MoO_3、SO_4~(2-)/TiO_2-Nd_2O_3和SO_4~(2-)/TiO_2-Fe_2O_3,并用于合成水杨酸异戊酯,实验表明,SO_4~(2-)/TiO_2-Nd_2O_3催化活性最高。利用热分析、红外光谱分析、扫描电子显微镜和X射线粉末衍射分析对SO_4~(2-)/TiO_2-Nd_2O_3催化剂进行结构表征,结果表明,催化剂活性高低与其表面吸附的SO_4~(2-)量有关,浸渍硫酸的催化剂表面形貌和物相发生变化,进而影响催化剂性能。采用三因素二水平一次回归正交设计方法,确定酯化反应最佳反应条件:反应时间1 h,催化剂用量为水杨酸质量的14.5%,醇与酸物质的量比为0.56。对水杨酸异戊酯产品结构进行了表征。

Preparation of SO2-4 /TiO2-MxOy solid superacid and its activity for esterification

SO4^2-/TiO2-MoO3, SO4^2-/TiO2-Nd2O3 and SO4^2-/TiO2-Fe2O3 solid superacid was prepared and used as the catalyst for synthesis of isoamyl salicylate. The experimental results showed that SO4^2-/TiO2-Nd2O3 exhibited the highest catalytic activity. Structure of the catalyst was characterized by thermal analysis, IR, SEM and XRD. The results showed that the catalytic activity was dependent on quantity of SO4^2- adsorbed, which caused changes in surface topography and phase of the catalyst and hence affected behaviors of the catalyst. Optimum condition for the esterification reaction was obtained as follows by linear regression orthogonal design： reaction for I h, catalyst dosage = 14.5% of the mass of salicylic acid, n（isoamyl alcohol） ： n（ salicylic acid） = 0.56. Structure of the isoamyl salicylate synthesized was characterized.