Synthesis of Novel Porous Silica/Montmorillonite Composites by Gallery-Template Structure-Directing Method
层间模板剂导向合成新型多孔蒙脱石材料的研究

The purified natural montmorillonites were modified by cetyltrimethylammonium bromide (CTAB) and octadecyltrimethylammonium chloride respectively. Mixtures of the modified montmorillonites, neutral amine and tetraethylorthosilicate (TEOS) at a molar ratio of 1:20:150 were allowed to react for 8h. The resulting intercalates were centrifuged, dried in air and calcined at 540?C for 4h to burn off the organic templates, a series of novel porous silica/montmorillonites composites were successfully synthesized by the gallery-template structure-directing process. The structure of the samples was characterized by XRD, TG, FT-IR, N2 adsorption-desorption isotherms and acid-catalyzed alkylation probe reaction. The results show that the samples synthesized have a narrowly pore distribution and super-gallery height, a large BET specific area. With the increasing of chain length of neutral amine, the pore size and gallery height increase accordingly. The synthetic materials are potentially effective solid acid catalysts for the Friedel-Crafts alkylation of catechol with tert-butyl alcohol to synthesize butyl 4-tert-butylcatechol (4-TBC). Over synthetic porous material by using CTAB and hexylamine as template, the selectivity to 4-TBC of 78.5% and catechol conversion of 45.5% can be obtained under experimental condition.