(中南大学 化学化工学院，长沙 410083)
摘 要: 为探究超声场作用强化过饱和铝酸钠溶液分解的机理，采用量子化学密度泛函计算方法，分析Al3-B基团的几何性质和羟自由基进攻的活性部位；同时设计了羟自由基参与Al3-B基团环合反应的可能路径；通过反应势能面扫描分析，优化得到反应路径上的过渡态和中间体的几何构型，利用振动频率分析对过渡态和中间体进行了确认。结果表明：羟自由基有两条可能的反应路径参与Al3-B基团的环合反应，其活化能均为109 kJ/mol，比无自由基参与时的降低约70 kJ/mol。
关键字: Al3-B基团；羟自由基；环合反应；密度泛函理论
（School of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China）
Abstract:To investigate the decomposition mechanism of supersaturated sodium aluminate solution with ultrasound, an advanced quantum chemical calculation technique with density functional theory (DFT) was used. The model geometry of Al3-B cluster and the relevant part of reactivity were determined. The possible paths of cyslization reaction for Al3-B cluster with ？OH radical were also designed. Meanwhile, the geometries of transition states and intermediates were optimized and verified by PES and frequency calculation. The results show that the ·OH radical is beneficial to the appearance of circled growth unit [Al6(OH)22(H2O)2]4-. There are two possible paths of polymerization of Al3-B cluster with ·OH radical. The activity energy is 109 kJ/mol, which is decreased by about 70 kJ/mol.
Key words: Al3-B cluster; ·OH radical; cyclization reaction; density functional theory
