School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai, 200240, P. R. China.
Dalton Trans. 2014 Mar 7;43(9):3612-7. doi: 10.1039/c3dt53308e.
Quaternary ammonium salts are well-known zeolite structure-directing agents. However, cationic surfactants with quaternary ammonium head groups are known to fail to function as SDAs of zeolites because their long surfactant chains disrupt the ordered growth of the zeolite crystals. In this study, we found that ZSM-5 and silicalite-1 can be formed very easily with appropriate synthesis compositions over a large temperature range of 100-200 °C. The (13)C CP/MAS data for surfactants in ZSM-5 combined with elemental analysis indicated that the surfactants were in more rigid, isolated environments and did not undergo decomposition. The surfactant head groups can serve as structure-directing agents for zeolites, and the long chains become isolated and occupy the micropores. Our findings provide a new insight into the molecular factors governing the formation of inorganic-organic microporous materials, which opens up new possibilities for the elaborate fabrication of mesoporous zeolites.
季铵盐是众所周知的沸石结构导向剂。然而，具有季铵头基的阳离子表面活性剂由于其长的表面活性剂链会破坏沸石晶体的有序生长，因此不能作为沸石的 SDA。在这项研究中，我们发现 ZSM-5 和 silicalite-1 可以在非常宽的温度范围 100-200°C 下，通过适当的合成组成很容易形成。ZSM-5 中表面活性剂的 (13)C CP/MAS 数据结合元素分析表明，表面活性剂处于更刚性、孤立的环境中，并且没有发生分解。表面活性剂头基可以作为沸石的结构导向剂，长链变得孤立并占据微孔。我们的发现为控制无机-有机微孔材料形成的分子因素提供了新的见解，为介孔沸石的精心制备开辟了新的可能性。
