Liu Aifeng, Che Hongwei, Liu Chuanzhi, Fu Quanrong, Jiang Ruijiao, Wang Cheng, Wang Liang
J Nanosci Nanotechnol. 2014 Jun;14(6):4584-9. doi: 10.1166/jnn.2014.8067.
Ordered hexagonal mesoporous aluminosilicates with lower Si/Al ratio below 5 have been successfully synthesized via the co-assembly of preformed aluminosilicate precursors with Gemini surfactant [C12H25N+(CH3)2(CH2)6N+(CH3)2C12H25] x 2Br(-) as the template. Powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, N2 adsorption-desorption isotherm measurements, Fourier transform infrared spectroscopy, 27Al nuclear magnetic resonance, thermogravimetric analysis, and temperature-programmed desorption of cyclohexylamine are employed to characterize the resulting samples. The phenol alkylation reaction is carried out to evaluate their catalytic performances. These studies indicate that the sample with a low Si/Al ratio of 3 still retains a highly ordered hexagonal mesoporous structure. And it also possesses the highest acidity of 0.96 mmol among the samples with lower Si/Al ratios below 5 due to its higher specific surface area together with more content of tetrahedrally coordinated Al in the framework. The catalytic tests confirm that the acidity of the samples plays a key role in determining their catalytic performances.
通过将预制的铝硅酸盐前驱体与双子表面活性剂[C12H25N+(CH3)2(CH2)6N+(CH3)2C12H25] x 2Br(-)作为模板进行共组装，成功合成了Si/Al比低于5的有序六方介孔铝硅酸盐。采用粉末X射线衍射、透射电子显微镜、扫描电子显微镜、N2吸附-脱附等温线测量、傅里叶变换红外光谱、27Al核磁共振、热重分析和环己胺程序升温脱附等方法对所得样品进行表征。进行苯酚烷基化反应以评估其催化性能。这些研究表明，Si/Al比为3的低Si/Al比样品仍保留高度有序的六方介孔结构。并且由于其较高的比表面积以及骨架中四面体配位Al的含量更高，在Si/Al比低于5的样品中，它还具有0.96 mmol的最高酸度。催化测试证实，样品的酸度在决定其催化性能方面起关键作用。
