Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
ACS Appl Mater Interfaces. 2011 Jun;3(6):2154-60. doi: 10.1021/am200380a. Epub 2011 Jun 6.
This paper describes a method to regulate porosity of Ti-containing mesoporous molecular sieves (Ti-MCM-41) by employing swelling agents that are hydrophobic in nature, such as dodecylamine, n-heptane, and sym-trimethylbenzene (TMB). Physicochemical properties of the samples were investigated using XRD, FT-IR, IR spectra of pyridine absorption, UV-vis, TEM, and N(2) adsorption-desorption techniques. Addition of favorable swelling agents leads to an increase in pore size accompanied by retaining the mesostructure with a certain decrease of structure ordering. Swelling agents also have significant impact on the integration of Ti into the silica framework, which further affect the formation of Lewis acid sites. N-heptane is the most favorable agent for pore expansion of Ti-MCM-41. The material with n-heptane/CTAB ratio of 1 exhibits the largest pore size of 48.3 Ǻ, and mesopore volume of 1.266 cm(3)/g and narrow pore-size distribution. We also demonstrated that shape-selective transesterification catalytic activity of Ti-MCM-41 was greatly enhanced because of pore expansion.
本文介绍了一种通过使用疏水性的膨胀剂（如十二胺、正庚烷和均三甲苯）来调节含钛介孔分子筛（Ti-MCM-41）的孔隙率的方法。采用 XRD、FT-IR、吡啶吸附红外光谱、UV-vis、TEM 和 N2 吸附-脱附技术对样品的物理化学性质进行了研究。添加合适的膨胀剂会导致孔径增大，同时保留介孔结构，结构有序度略有降低。膨胀剂对 Ti 进入二氧化硅骨架的整合也有显著影响，从而进一步影响 Lewis 酸位的形成。正庚烷是 Ti-MCM-41 孔膨胀的最有利试剂。正庚烷/CTAB 摩尔比为 1 的样品表现出最大的孔径为 48.3 埃，介孔体积为 1.266 cm3/g，且具有较窄的孔径分布。我们还证明，由于孔的膨胀，Ti-MCM-41 的酯交换选择性催化活性大大增强。
