CAJ | 학술논문

基于量子化学中的密度泛函理论(DFT),通过β分子筛同模板剂四乙胺阳离子(TEA~+)的主客体相互作用来讨论了模板剂分子对骨架Al的靶向作用.计算采用了密度泛函理论中的B3LYP方法在6-31G(d,p)基组上研究了β分子筛同TEA~+主客体相互作用的几何结构、分子轨道、电荷分布以及9个不同骨架位置的相互作用能.研究结果表明:带正电荷的TEA~+吸引β分子筛上Al原子形成的阴离子中心(Zeo-AlO_4~-),两者具有很好的匹配关系.通过主客体相互作用影响了Al原子在分子筛中的分布.骨架Al最有利于落位在β分子筛的T5和T6位,落位的稳定性顺序是Group Ⅱ(T5,T6)>Group Ⅲ(T7-T9)>Group Ⅰ(T1-T4).
기우양자화학중적밀도범함이론(DFT),통과β분자사동모판제사을알양리자(TEA~+)적주객체상호작용래토론료모판제분자대골가Al적파향작용.계산채용료밀도범함이론중적B3LYP방법재6-31G(d,p)기조상연구료β분자사동TEA~+주객체상호작용적궤하결구、분자궤도、전하분포이급9개불동골가위치적상호작용능.연구결과표명:대정전하적TEA~+흡인β분자사상Al원자형성적음리자중심(Zeo-AlO_4~-),량자구유흔호적필배관계.통과주객체상호작용영향료Al원자재분자사중적분포.골가Al최유리우락위재β분자사적T5화T6위,락위적은정성순서시Group Ⅱ(T5,T6)>Group Ⅲ(T7-T9)>Group Ⅰ(T1-T4).
Guest/host interaction between the tetraethylammonium (TEA) cations molecule and the model cluster of zeolite, calculated with DFT method, was used to investigate the Al preferential location in β zeolite. The calculations were performed based on cluster model by using of B3LYP hydride functional and 6-31G (d, p) basis set. For these species the geometries, molecular orbitals, Mulliken atomic, and interaction energies were analyzed. According to the calculated results of orbital picture and charge distribution it was proposed that the template has a good fit with the host framework and the role of the template is shown to be crucial in order to elucidate the Al distributions. Therefore, the energetics during the synthesis process (zeolite+template) that has to be considered, and in this scene the template accommodation within the microporous space acts not only as a structure director but also as a director of the AI distribution. Based on the distances and energies of the guest/host interaction about different T (T=Al) sites, it was predicated that the T5 and T6 sites are the most stable sites for the substitution of Al in the β zeolite framework; and the stability is in the order of Group Ⅱ(T5,T6)>Group Ⅲ (T7-T9)>Group Ⅰ(T1-T4).