Aluminosilicate MCM-48 mesostructures assembled from dried zeolite precursors and Gemini surfactant

• Main Authors: Hsin-Mow Wu, 吳欣茂
• Other Authors: Hsien-Ming Kao
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/40845317967722704575

碩士 === 國立中央大學 === 化學研究所 === 92 === Aluminosilicates with well-ordered MCM-48 mesostructures have been prepared via the assembly of “dried” zeolite precursors with Gemini surfactant. The aluminosilicate MCM-48 materials obtained were characterized by a variety of techniques including powder X-ray diffraction (XRD), 27Al and 29Si magic angle spinning (MAS) NMR, IR, transmission electron microscope (TEM), scanning electron microscope (SEM), nitrogen sorption measurements. The use of Gemini surfactant and the dried zeolite precursor facilitated the incorporation of higher Al contents (Si/Al ratio up to 20) into MCM-48 framework without compromising the integrity of the cubic mesostructure. In comparison to the Al-MCM-48 sample prepared via the direct synthesis, the materials assembled from zeolite precursors showed higher hydrothermal stability and better cumene cracking activities. Although the dried precursors of MFI and BEA zeolites could not be differentiated by all physical measurements made, the catalytic cracking activity of their derived samples did show differences. By varying the temperatures for the preparation of zeolite precursor and for the hydrothermal treatment after surfactant addition, materials ranging from zeolitic MCM-48, zeolite/MCM-48 composite, and pure zeolite nanocrystals could be obtained.