| 研究実績の概要 |
In this research project, computational chemistry calculations together with experimental works have been carried out in order to synthesize zeolites with the ultimate goal being the control of the aluminum sites in zeolites. In particular, computational methods are being developed to design organic structure-directing agents (OSDAs) that can fit well with the targeted zeolite frameworks and thereby possibly controlling the aluminum sites. In FY 2014 (平成26年度), OSDAs were designed computationally by quantum chemistry-based calculations. The designed OSDAs were synthesized and used to prepare nanoporous silica. The resulting materials exhibit some periodicity, high surface area (up to 1,230 m2/g), and pore diameters near the boundary between micro- and mesopores. The pore diameters can be altered across the boundary between micro- and mesopores, ranging from 1.5 to 3 nm, depending on the OSDAs. A possible formation scheme can be explain based on multiple, orthogonal interactions between OSDAs, co-OSDAs and silica frameworks. These results suggest that the calculation methods used here are effective to design OSDAs.
In addition to OSDA designs, molecular mechanics calculations assisted by Monte-Carlo method have been developed for large-scale evaluation of physico-chemical properties of zeolites with a wide variety of framework topologies, a wide range of Si/Al, and different crystallographic sites of aluminum. The results suggest that the stability of zeolites depends not only on framework topology, but also on aluminum contents and sites.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
As the original research plan, in the first year (FY 2014, 平成26年度) the computational method was developed to design OSDAs. The designed OSDAs were synthesized and used to prepare nanoporous silica. The achievements in the first year are a fundamental part for the continuing research in the second year.
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| 今後の研究の推進方策 |
Based on the results obtained so far, calculation methods will be further improved for better design of OSDAs and deeper understanding of effects of aluminum sites on the physico-chemical properties of zeolites. From the calculation results, the aluminosilicate zeolites will be synthesized and the effects of OSDAs on aluminum sites will be clarified.
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