Mesoporous silica functionalized with phenylsulfonic acid is prepared by sol-gel technique to form a precursor bearing phenyl groups followed by sulfonation.The characterization of nitrogen adsorption-desorption indic...Mesoporous silica functionalized with phenylsulfonic acid is prepared by sol-gel technique to form a precursor bearing phenyl groups followed by sulfonation.The characterization of nitrogen adsorption-desorption indicates that the specific area of the material is 722 m2/g,the average pore size is 9.06 nm and pore volume is 0.59 cm3/g.The material is examined as acid catalyst in aldol condensation reaction of cyclohexanone.The results show that the material featured higher catalytic performance than those of conventional concentrated sulfuric acid and p-toluene sulfonic acid,and it is found that the main factors which determine the catalytic activity of the mesoporous silica functionalized with phenylsulfonic acid involve its acid center,surface property,and porosity structure.展开更多
文摘采用乙二胺对磺酸型阳离子交换树脂进行胺化改性,并运用CHNS元素分析及傅里叶变换红外光谱对改性树脂进行了表征。结果表明,胺化改性后树脂含氮量为0.94 mmol?g?1,改性后树脂骨架结构变化不大,胺基成功固载到树脂上,碱性增强,使氢型树脂成为具有酸碱双功能的催化剂。在催化环己酮缩合反应中考察了胺化量、催化剂用量、反应温度、反应时间、带水剂种类及用量等条件对反应的影响。实验结果表明,以甲苯为带水剂效果较好。在5%(wt)胺化量改性树脂,10%(wt)催化剂用量,7 m L甲苯为带水剂,120℃反应3 h的优化条件下,环己酮转化率为62.1%,二聚物选择性98.0%,体现出了酸碱协同催化环己酮缩合反应优异性能。改性树脂重复使用5次后,催化性能仍较稳定。
文摘Mesoporous silica functionalized with phenylsulfonic acid is prepared by sol-gel technique to form a precursor bearing phenyl groups followed by sulfonation.The characterization of nitrogen adsorption-desorption indicates that the specific area of the material is 722 m2/g,the average pore size is 9.06 nm and pore volume is 0.59 cm3/g.The material is examined as acid catalyst in aldol condensation reaction of cyclohexanone.The results show that the material featured higher catalytic performance than those of conventional concentrated sulfuric acid and p-toluene sulfonic acid,and it is found that the main factors which determine the catalytic activity of the mesoporous silica functionalized with phenylsulfonic acid involve its acid center,surface property,and porosity structure.
