Catalytic Properties of Sulfonic Acid-functionalized Mesoporous Silica Prepared in Alkaline Environment

• Main Authors: Yi-Lin Chen, 陳宜琳
• Other Authors: Soofin Cheng
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/85307405902684358072

碩士 === 國立臺灣大學 === 化學研究所 === 99 === Mesoporous silica materials have potential applications in sorption, catalysis and optoelectronic devices. For practical applications, the porous structure and framework stability are the main concerns. In this study, two sulfonic acid-functionalized mesoporous materials were synthesized using cetyltriethylammonium (CTEA+) ion as pore-directing agent by one-pot co-condensation of sodium silicate (Na2SiO3) and (3-mercaptopropyl)trimethoxysilane (MPTMS) in alkaline condition (pH~10). After the templating surfactants were removed, the thiol groups were oxidized to sulfonic acid groups by H2O2. Well-ordered functionalized mesoporous silica materials of 2D-hexagonal (p6mm) and 3D-cubic (Pm3n) structures with sulfonic acid contents (S/Si molar ratio) up to 1.53 mmol H+/g were obtained in the presence of NO3- and Cl- anions, respectively. . The catalytic properties of these materials in esterifications of carboxylic acids of different chain lengths (lauric acid or acetic acid) with methanol or benzylalcohol were examined, and the results were compared with that of sulfonic acid-functionalized MCM-41. The initial rates of esterification over cubic Pm3n material were faster than that over 2D-hexagonal materials, attributing to the easier diffusion of the reactants in the 3D-pores than 2D-channels.