Abstract: Fe₃O₄@SiO₂ nanocomposite was prepared via modified Stöber method and used as catalyst support. Superparamagnetic supported catalystsprepared by loading H₃PW₁₂O₄₀ (HPW) onto Fe₃O₄@SiO₂ support through a wet impregnation method, were used for alkylation reaction, and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), NH₃-temperature programmed desorption (TPD), scanning electron microscope (SEM), N₂-adsorption and vibrating sample magnetometer (VSM). Their physicochemical characterization revealed that HPW had been immobilized and dispersed on Fe₃O₄@SiO₂. Moreover, 40%(mass) HPW loading catalyst, been of high magnetization 30.1 emu·g^-1, mesoporous structure and the surface area 303.6 m²·g^-1, could be considered to be a proper catalyst for olefinic alkylation of thiophenic sulfur (OATS) and they can be easy separated by external magnetic field. In addition, their catalytic activity was also investigated in alkylation reaction of a model mixture of thiophene and 1-octene, and the conversion of thiophene was up to 85.5% after 2 h at 160℃.

Key words: superparamagetism, alkylation, phosphotungstic acid, catalyst, composites, silica

摘要： 采用改进Stöber法制备超顺磁Fe₃O₄@SiO₂复合粒子作为催化剂载体，再通过浸渍法将H₃PW₁₂O₄₀（HPW）负载在Fe₃O₄@SiO₂载体上，制备了一系列超顺磁负载型催化剂HPW/Fe₃O₄@SiO₂。并使用X射线衍射（XRD）、傅里叶红外（FT-IR）、氨的程序升温脱附（NH₃-TPD）、扫描电镜（SEM）、N₂吸附-脱附和振动样品强磁计（VSM）对催化剂进行表征。结果表明，HPW固定并均匀分散在Fe₃O₄@SiO₂载体上，40% HPW/Fe₃O₄@SiO₂催化剂具有较高的饱和磁强度 （30.1 emu·g^-1）和较大的比表面积 （303.6 m²·g^-1），并可用外加磁场进行分离。采用40% HPW/Fe₃O₄@SiO₂催化噻吩与1-辛烯组成的模拟汽油的烷基化脱硫反应，在160℃下反应2 h，噻吩转化率达到85.5%，有较好的催化脱硫性能，且可以多次循环利用。

关键词: 超顺磁性, 烷基化, 磷钨酸, 催化剂, 复合材料, 二氧化硅