(中南大學 化學化工學院， 長沙 410083)
摘 要: 應用量子化學從頭算密度泛函理論以及DFT/COSMO溶劑模型， 基于 UHF/BLYP/DNP水平對高苛性比中等濃度鋁酸鈉溶液中各類離子(分子)的溶劑化作用進行研究。 根據(jù)離子(分子) 的幾何構型、總能量、振動頻率、相關熱力學數(shù)據(jù)以及相應的水合自由能，對溶液中離子(分子)的存在形式以及不同離子(分子)間的平衡轉化關系進行分析。 結果表明， 在高苛性比中等濃度鋁酸鈉溶液中，鋁主要是以水合Al(OH)4-離子和Na(H2O)6+Al(OH)4-離子對形式存在，同時還存在有中性水合分子Al(OH)3H2O。
關鍵字: 鋁酸鈉溶液； 密度泛函； 溶劑化作用； 水合自由能
HU Hui-ping, ZHANG Ping-min
（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
