(中南大學(xué) 化學(xué)化工學(xué)院，長(zhǎng)沙 410083)
摘 要: 為探究超聲場(chǎng)作用強(qiáng)化過(guò)飽和鋁酸鈉溶液分解的機(jī)理，采用量子化學(xué)密度泛函計(jì)算方法，分析Al3-B基團(tuán)的幾何性質(zhì)和羥自由基進(jìn)攻的活性部位；同時(shí)設(shè)計(jì)了羥自由基參與Al3-B基團(tuán)環(huán)合反應(yīng)的可能路徑；通過(guò)反應(yīng)勢(shì)能面掃描分析，優(yōu)化得到反應(yīng)路徑上的過(guò)渡態(tài)和中間體的幾何構(gòu)型，利用振動(dòng)頻率分析對(duì)過(guò)渡態(tài)和中間體進(jìn)行了確認(rèn)。結(jié)果表明：羥自由基有兩條可能的反應(yīng)路徑參與Al3-B基團(tuán)的環(huán)合反應(yīng)，其活化能均為109 kJ/mol，比無(wú)自由基參與時(shí)的降低約70 kJ/mol。
關(guān)鍵字: Al3-B基團(tuán)；羥自由基；環(huán)合反應(yīng)；密度泛函理論
（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
