不同三维介孔二氧化硅微球固体酸的合成

Synthesis of mesoporous silica microspheres solid acid with different 3D pore structure

合成了不同三维孔道结构的介孔二氧化硅微球,以其为载体通过浓硫酸磺化法制备了系列磺酸基二氧化硅微球固体酸,并利用扫描电镜、透射电镜和氮气脱附-吸附等手段对其结构进行表征。以乙酸和乙醇的酯化反应为探针,考察磺化温度和时间对不同结构催化剂活性的影响。结果表明,经磺化处理后磺酸基团成功负载到了二氧化硅微球上,且微球的形貌和孔道结构未发生改变。磺化初期,载体的孔道结构是影响催化活性主导因素,孔结构开阔的泡沫状孔道微球固体酸更具优势;随磺化时间的延长,其比表面积大小成为决定催化剂活性的主要因素,比表面积大的蠕虫状孔道微球固体酸催化效果更佳。在240°C下,磺化6 h制得的蠕虫状孔道微球固体酸负载量达到6.51%,表现出最佳的催化效果。

Mesoporous silica spheres materials with different 3D pore structure and properties were prepared,and a series of sulfonate silica microspheres solid acid was synthesized by sulfonated sulfonation method using these mesoporous silica spheres as supports.The physicochemical properties of those catalysts were characterized using scanning electron microscope(SEM),transmission electron microscopy(TEM),and nitrogen adsorption/desorption.Using the esterification reaction of acetic acid and ethanol as probe,the effects of the sulfonated temperature and time on the activity of different structure catalysts were investigated.The results show that the morphology and pore structure of the silica microspheres are not changed after sulfonation.At the beginning of the sulfonation,the catalytic performance was governed by the pore structure of the support.Large pore size and open framework made the cellular structure silica microspheres(MCF)superior to other catalysts.With the extension of sulfonation time,the catalytic performance of the catalyst is determined by the surface area and worm-like mesoporous silica spheres solid acid with larger surface area had higher catalytic activities.The worm-like mesoporous silica spheres solid acid synthesized at 240°C for 6 h with a load rate of 6.51%,shows the best catalytic performance.