(中南大学 化学化工学院， 长沙 410083)
摘 要: 应用量子化学从头算密度泛函理论以及DFT/COSMO溶剂模型， 基于 UHF/BLYP/DNP水平对高苛性比中等浓度铝酸钠溶液中各类离子(分子)的溶剂化作用进行研究。 根据离子(分子) 的几何构型、总能量、振动频率、相关热力学数据以及相应的水合自由能，对溶液中离子(分子)的存在形式以及不同离子(分子)间的平衡转化关系进行分析。 结果表明， 在高苛性比中等浓度铝酸钠溶液中，铝主要是以水合Al(OH)4-离子和Na(H2O)6+Al(OH)4-离子对形式存在，同时还存在有中性水合分子Al(OH)3H2O。
关键字: 铝酸钠溶液； 密度泛函； 溶剂化作用； 水合自由能
（College of Chemistry and Chemical Engineering,
Central South University, Changsha 410083, China）
Abstract: There is a higher Na/Al mole ratio for sodium aluminate solution of medium concentration during the ended crystallized process of gibbsite. In order to elucidate the solvent effect of species and their relevant microcosmic properties in the solution, DFT quantum mechanical calculations were firstly performed on various species of aluminate ions and ion pairs at the UHF/BLYP/DNP level. Energies, geometries, vibrational frequencies of the probable species were calculated respectively in vacuum and in solution, and their relevant hydrated free energies were also obtained by DFT/COSMO. By analyzing the calculated results, it is concluded that hydrated Al(OH)-4 is the major ingredient in sodium aluminate solutions of medium concentration with a high Na/Al mole ratio, neutral hydrate Al(OH)3H2O can exist and the major hydrated form of ion pair is solvent-separated Na(H2O)6+Al(OH)4- in the solution.
Key words: sodium aluminate solution; DFT; solvent effect; hydrated free energy
