杂原子硅介孔分子筛的超临界相合成

We have carried out the study of hydrolysis-condensation reactions of TEOS in supercritical ethanol-water medium. The addition of TEOS precursor by a high-pressure pump led to the preparation of regular spherical silica particles with proper size under control. Then, under the directing of CTAB or PEG, the mesoporous molecular sieves materials with higher thermal and hydrothermal stability were synthesized. The specific surface and the pore volume of the materials increased in a certain degree by changing the concentration of the directing agent and the kind of catalyst. MCM-41 and MCM-48 were obtained under low crystallized temperature and high pressure. Using sol-gel process, the mesoporous molecular sieves with high stability were synthesized. The materials have been proved to possess higher catalytic properties and hydrothermal stability by using the alkylation of naphthalene as probe reactions. In the meantime, we studied the synthesis of organically functionalized MSU-X silicas and their use in fine chemicals. In addition, we have performed a systematic study on SAXS（Small Angle X-Ray Scattering）method and its application in mesoporous materials, and some interesting results have been derived.

针对ＳｉＯ２溶胶体系，研究模板分子聚集体与溶胶粒子之间的相互作用，通过软化学途径，现骨架结构的″分子设计与裁减″。引入超临界合成技术可望提高其介孔结构的热稳定性和水热稳定性，保证业已形成的分维孔道性质，有利于模板剂的脱除。这一课题无论在基础理论还是在工业应用前景方面无疑都具有深远的科学意义。