摘要
近年来,越来越多的材料和催化领域的科学家开始关注于中孔(孔径范围2～50nm)分子筛M41S系列的合成、应用及其形成机理.M41S系列是通过静电自组装(S^+I^-,S^+:阳离子表面活性剂;I^-:阴离子无机物种)途径合成的,由三种晶形的成员组成:六方相MCM-41,立方相MCM-48和热不稳定的层状相MCM-50.其中,MCM-41的一维直孔道由于易被外来物质堵塞,其催化、吸附或载体性能受到不利影响,然而,MCM-48结构中相互交织的三维孔道系统使之对孔道堵塞不敏感,但是用单一季铵盐型阳离子表面活性剂做模板剂合成MCM-48的条件较苛刻,目前大量的文献仍集中于MCM-41.Stucky等报道了用两种二价阳离子表面活性剂C_(16-12-16)和C_(16-3-1)的混合物作模板剂。
A mixed neutral - cationic surfactant templating pathway is disclosed for the first time to demonstrate the easy synthesis of cubic phase MCM - 48. In this approach, commercially available neutral surfactant n - dodecylamine (DDA) is selected along with cationic surfactant cetyltrimethyl -ammonium bromide (CTAB) to assemble the micelle leading to some changes on the properties of the MCM-48 thus obtained. The synthesis is conducted at a low mass fraction of mixed surfactant (4%) and a low molar ratio of total surfactants to silica (0. 16). The unit cell parameter of MCM - 48 is tunable in sub - angstrom precision by simply varying the amount of DDA in the mixed micelle. A more extensively cross - linked framework and therefore a higher thermal stability in our MCM - 48 materials can be achieved with the introduction of DDA to the mixed surfactant micelle. Templating pathway by mixing different sorts of surfactants may provide for the facile synthesis of mesoporous molecular sieves with different properties.
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
1998年第12期1214-1217,共4页
Acta Chimica Sinica
基金
国家自然科学重点基金资助项目(29733070)
关键词
中孔分子筛
DDA
CTAB
MCM-48
模板
水热合成
MCM - 48, mixed surfactant micelle, n - dodecylamine, templating, hydrothermal synthesis
