关键词: B酸强度, 非骨架铝, 密度泛函理论, 分子动力学

Abstract: Brønsted acid in Y zeolite plays a key role in the processes of catalyst,and the structure reflects the strength of B acid.The stable structures of Brønsted acid sites of HY,[AlO]+/HY,and [Al(OH)]2+/HY were simulated by periotic models.The relationship between the structures of Brønsted acid sites and its environments was identified by combination of dynamic simulation with DFT calculation.By analyzing the structure and electronic permanent,together with the statistical results of molecular dynamics,it can be found that the strength of Brønsted acid can connected with the number of H atoms in the 12 membered ring that the small number.The weaker the binding ability of H atoms to O atoms in B acid center is,and the more electrons H atoms lose,the stronger the B acid acidity is.The addition of extra⁃framework aluminum can enhance the acidity of B acid,and [Al(OH)]2+ has more obvious effect on B acid properties.These results can lead the synthetic and modification of B acid site in a theoretical support.

Key words: Strength of Brønsted acid, Extra?framework aluminum, Density functional theory, Molecular dynamics