Application of hard-soft acid-base principle to study Bronsted acid sites in zeolite clusters: a quantum chemical study
Application of hard-soft acid-base principle to study Bronsted acid sites in zeolite clusters: a quantum chemical study
复制标题
DOI：
10.1021/jp984267k
复制
发表时间：
1999-07-29
影响因子：
2.9
通讯作者：
Pal, S
中科院分区：
文献类型：
--
作者：
Deka, RC;Vetrivel, R;Pal, S
通过计算技术研究了沸石骨架四面体位点中 Al、B 和 Ga 同晶取代 Si 对布朗斯台德酸位点性能的影响。我们使用基于密度泛函理论（DFT）的酸度描述符“局部柔软度”和新的酸度描述符“相对亲电性”来预测沸石簇的酸度序列。有限差分近似用于计算局部柔软度。发现相对亲电性是沸石簇酸度的合适描述。由局部软度值得出的酸度趋势取决于多种因素，例如基组、沸石簇的几何形状以及用于计算它们的不同总体分析。由相对亲电性得出的酸度趋势遵循实验趋势，并且不受基组或簇模型的选择影响。
The effect of isomorphous substitution of Si by Al, B, and Ga in the tetrahedral sites of a zeolite framework on the properties of Bronsted acid sites is investigated by computational techniques. We used the density functional theory (DFT) based acidity descriptor, "local softness", and a new acidity descriptor, "relative electrophilicity" to predict the acidity sequence of the zeolite clusters. The finite difference approximation is used to calculate local softness. The relative electrophilicity is found to be a suitable descriptor of acidity of zeolite clusters. The trend of acidity derived from local softness values depends on several factors such as basis sets, geometry of zeolite clusters, and different population analyses used to calculate them. The acidity trend derived from the relative electrophilicity follows the experimental trend, and it is not affected by the choice of basis sets or cluster models.