质子型离子液体中新型微孔磷酸盐材料的合成及气体吸附分离性能研究

Much efforts have been made to synthesize novel microporous metal phosphate materials, because of their important application values in the fields of adsorption, separation and catalysis. Recently, the developed ionothermal synthesis shows great potential for the preparation of novel metal phosphate frameworks, however, it is also difficult to further produce novel frameworks from the conventional imidazolium-based ionic liquids, because of the limitation of template role of the imidazolium cations. Therefore, the project intends to develop a new kind of ionic liquid to synthesize new microporous metal phosphates. The ammonium-based protic ionic liquid in this project is different from the typical imidazolium-based ionic liquids, and its cation component is very rich and almost includes all the organic amines and their derivatives, which provides wide space to select the suitable template agent for the ionothermal syntheses. By studying the relationship between the ionic liquid (organic cation and anion) and phosphate framework, such as the dimension of the pore channel, pore window size and pore volume, we can design and synthesize a kind of desired ammonium-based protic ionic liquid to rationally synthesize new microporous phosphates with small pore window and large pore volume, which can act as a very effective adsorbent for the adsorption separation of methane and carbon dioxide from biogas to obtain pure or more concentrated methane.

金属磷酸盐微孔材料在吸附、分离和催化领域具有重要的应用价值，具有新型结构且性能优良的磷酸盐微孔材料的合成备受关注。近年来，离子热合成法在制备新型结构的磷酸盐微孔材料方面呈现出很大潜力，但传统的咪唑基离子液体作为反应介质和模板剂，其有机阳离子组分的模板功能比较单一，致使进一步合成新型结构的磷酸盐遇到困难。本项目拟突破经典的咪唑基离子液体，探索新的离子热反应介质（胺类质子型离子液体）用于磷酸盐微孔材料的合成，其丰富的有机阳离子组分几乎涵盖了所有的有机胺及其衍生物，为离子热合成中模板剂的选择提供了广阔的空间。我们期望通过研究此类离子液体的阳离子结构和阴离子组分与合成磷酸盐骨架（孔道维数、孔径和孔容等）的关系和规律，以此为指导来设计并合成出有效的质子型离子液体来定向合成小孔口、大孔容的新型微孔磷酸盐材料，为生物质沼气中分离CO2和CH4获得高浓度甲烷提供性能优良的吸附分离材料。

金属磷酸盐微孔材料在吸附、分离和催化领域具有重要的应用价值，具有新型结构且性能优良的磷酸盐微孔材料的合成备受关注。近年来，离子热合成法在制备新型结构的磷酸盐微孔材料方面呈现出很大潜力，但传统的咪唑基离子液体作为反应介质和模板剂，其有机阳离子组分的模板功能比较单一，致使进一步合成新型结构的磷酸盐遇到困难。本项目主要围绕两大类新型的离子液体：脲基、羧酸类化合物和有机胺盐酸盐复配形成的质子型低共熔混合物、有机胺质子化的乙酸盐离子液体，开展了不同金属磷酸盐（ZrPO、CoPO、ZnPO和AlPO）微孔材料的合成研究，系统地研究了有机铵阳离子对不同的磷酸盐的模板控制或导向作用，通过调控离子液体的物化性质和优化合成体系，使得有机阳离子的模板作用得到充分的发挥，合成了20余种新型的金属磷酸盐微孔材料，针对它们的骨架维数和孔道结构的特点，系统地研究了它们对CO2和CH4的吸附分离性能，结果表明小于8-元环的孔道对CO2和CH4表现出良好的吸附选择性。深入总结了功能-结构-合成三者之间的关系与规律，揭示离子液体体系中磷酸盐微孔材料的模板作用机制，为定向合成高性能的磷酸盐微孔材料提供了理论指导。