【摘要】：離子液體作為綠色溶劑具有眾多優(yōu)良特性,近年來(lái)得到廣泛研究。研究離子液體獨(dú)特的性質(zhì)對(duì)于挖掘其潛在應(yīng)用前景具有深遠(yuǎn)意義。本論文使用理論計(jì)算和實(shí)驗(yàn)方法研究了離子液體溶解纖維素、離子液體捕集和存儲(chǔ)放射性碘和離子液體的可逆性、蒸餾性。本論文的主要研究?jī)?nèi)容和研究結(jié)論:1、使用纖維二糖作為模型利用理論計(jì)算和實(shí)驗(yàn)方法研究醋酸根離子液體溶解纖維素的機(jī)理。靜電勢(shì)能分布及結(jié)構(gòu)分析對(duì)復(fù)合物結(jié)構(gòu)特征進(jìn)行了解析。多種波函數(shù)分析方法,包括分子中原子理論(AIM)、約化密度梯度(RDG)、自然鍵軌道理論(NBO)等,都表明纖維二糖與離子液體的相互作用(包括氫鍵相互作用和范德華相互作用)強(qiáng)度與溶解度有關(guān)。實(shí)驗(yàn)表明升高溫度能顯著提高纖維素在[Bmim][OAc]中的溶解度。NMR表明纖維素與離子液體形成分子間氫鍵以及內(nèi)部固有的氫鍵斷裂使得纖維素能夠溶解于離子液體中。2、使用理論計(jì)算方法研究了1-丁基-3-甲基咪唑類離子液體捕集放射性碘的機(jī)理。結(jié)構(gòu)的設(shè)計(jì)及優(yōu)化參考了靜電勢(shì)能在分子表面的分布。相互作用能表明了復(fù)合物中放射性碘與離子液體、陰離子形成的鹵鍵強(qiáng)度。為了進(jìn)一步揭示離子液體捕獲放射性碘的機(jī)制,采用了電荷分布和振動(dòng)頻率分析探索原子電荷密度和振動(dòng)頻率的變化。使用自然鍵軌道理論(NBO)和分子中原子理論(AIM)表征了體系中的鹵鍵。實(shí)驗(yàn)和計(jì)算結(jié)果都表明放射性碘能被離子液體以1:1摩爾比捕獲。[Bmim][Br],[Bmim][I]和[Bmim][Cl]在5小時(shí)內(nèi)對(duì)碘的捕獲效率高達(dá)80%,表現(xiàn)出較好的捕獲效率和應(yīng)用潛力。3、利用理論計(jì)算和實(shí)驗(yàn)方法研究了十六種基于N-C=X(N,O and S)設(shè)計(jì)的可逆性的離子液體。靜電勢(shì)能分析表明N-C=X上X原子的高親核活性使得甲基轉(zhuǎn)移更容易實(shí)現(xiàn)。能量計(jì)算結(jié)果揭示了各離子液體的合成及其對(duì)應(yīng)的逆向反應(yīng)實(shí)現(xiàn)的難易程度。實(shí)驗(yàn)上合成了七種離子液體并通過(guò)熱重實(shí)驗(yàn)考察了其熱穩(wěn)定性。結(jié)果表明N-C=O類離子液體的初始分解溫度在250℃左右,故該離子液體的逆反應(yīng)在該溫度下易于實(shí)現(xiàn)。270℃溫度下[MMU][Tf O]的失重在6小時(shí)后小于20%表明其具高的熱穩(wěn)定性。鍵級(jí)分析、分子中原子理論(AIM)、約化密度梯度(RDG)和自然鍵軌道理論(NBO)等波函數(shù)分析方法表明非共價(jià)相互作用是實(shí)現(xiàn)甲基轉(zhuǎn)移的驅(qū)動(dòng)力。
[Abstract]:As a green solvent, ionic liquids have many excellent properties, which have been widely studied in recent years. It is of great significance to study the unique properties of ionic liquids for exploring their potential application prospects. In this paper, the reversibility and distillation of ionic liquid dissolved cellulose, ionic liquid trapping and storage of radioactive iodine and ionic liquid have been studied by theoretical calculation and experimental method. The main research contents and conclusions of this paper are as follows: 1. Using cellulose disaccharide as a model, the mechanism of cellulose dissolution by acetate ion liquid was studied by theoretical calculation and experimental method. The distribution and structure analysis of electrostatic potential energy were carried out to analyze the structural characteristics of the composite. A variety of wave function analysis methods, including (AIM), reduced density gradient (RDG), natural bond orbital theory (NBO), show that the strength of the interaction between cellulose disaccharide and ionic liquids (including hydrogen bond interaction and van der Waals interaction) is related to solubility. The experimental results show that the solubility of cellulose in [Bmim] [OAc] can be significantly improved by increasing the temperature. NMR shows that cellulose and ionic liquid form intermolecular hydrogen bond and internal inherent hydrogen bond fracture so that cellulose can dissolve in ionic liquid. 2. The mechanism of trapping radioactive iodine by 1-butyl3-methylimidazole ionic liquid has been studied by theoretical calculation method. The design and optimization of the structure refer to the distribution of electrostatic potential energy on the molecular surface. The interaction between radioactive iodine and anions in the complex shows the strength of halogen bonds formed by anions. In order to further reveal the mechanism of radioactive iodine capture by ionic liquids, charge distribution and vibration frequency analysis were used to explore the changes of atomic charge density and vibration frequency. The halogen bonds in the system were characterized by natural bond orbital theory (NBO) and molecular atomic theory (AIM). The experimental and calculated results show that radioactive iodine can be captured by ionic liquids at 1:1 molar ratio. [Bmim] [Br], [Bmim] [I] and [Bmim] [Cl] have high capture efficiency and application potential within 5 hours, showing good capture efficiency and application potential. 3. Sixteen kinds of reversible ionic liquids based on N-C=X (N, O and S) were studied by theoretical calculation and experimental method. Electrostatic potential energy analysis shows that the high nucleophilic activity of X atom on N-C=X makes methyl transfer easier. The results of energy calculation reveal the difficulty of the synthesis of each ionic liquid and its corresponding reverse reaction. Seven kinds of ionic liquids were synthesized and their thermal stability was investigated by thermogravimetric test. The results show that the initial decomposition temperature of N-C=O ionic liquid is about 250 鈩，

本文編號(hào)：2504333