| Summary: | 碩士 === 中原大學 === 化學系 === 88 === Abstract
Mesoporous molecular sieves MCM-41 were synthesized by using the micelles of the quaternary ammonium ion with long organic chains as a template in stead of a single molecule. Physical and chemical properties of purely siliceous and aluminosilicate mesoporous molecular sieves MCM-41 were characterized by the 27Al solid state nuclear magnetic resonance (NMR), powder X-ray diffraction, inductively-coupled plasma atomic emission spectroscopy (ICP) and nitrogen adsorption.
Three parts were investigated and included in this thesis. In the first part, mesoporous molecular sieves were successfully synthesized in acid and alkaline solution at room temperature. Trimethylbenzene (TMB) was used as a swelling agent to enlarge the pore size of these materials. However, powder X-ray diffraction results demonstrate the minor enlargement of unit cell. By using different reaction time form 2 h to 96 h, aluminosilicate mesoporous molecular sieves were synthesized at 165 ℃ in the second part. Pore size was gradually increased from 28.9 to 36.3 angstrom and wall thickness was also increased from 23.4 to 37.8 angstrom. These results illustrate that hydrothermal reaction time at high temperature has a significant influence on pore size and wall thickness for mesoporous molecular sieves. In final part, general [Si,Al]-MCM-41 is the catalyst of Na ion type and can be converted to the proton form of Bronsted acid through tedious processes of ion exchange and calcination. This project try to directly synthesize H+-[Si,Al]-MCM-41 to abridge these boring processes, not only to save the chemicals, energy sources and cost but also reduce time of procreation and lower pollution. Results of ICP, powder X-ray diffraction, 27Al solid-state NMR and N2 adsorption showed that scare Na+ was in these materials, aluminum was incorporated inside framework and aluminosilicate mesoporous molecular sieves of moderate quality were successfully synthesized and characterized. Beside, H+-[Si,Al]-MCM-41 by this project has much higher cumene cracking conversion and selectivity than tradition H+-[Si,Al]-MCM-41 from Na+-[Si,Al]-MCM-41 by ion exchange and calcination third times.
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