【作者】 樊俊丽；

【导师】 吴霞琴；

【作者基本信息】 上海师范大学 ， 物理化学， 2010， 硕士

【摘要】 离子液体作为绿色替代溶剂,在电化学中的应用涉及电镀、电池、有机电合成、电催化和电容技术等。与传统的有机溶剂和电解质相比,离子液体具有熔点低、液态温度范围宽、具有可忽略的蒸汽压、高的热稳定性、较好的化学稳定性、宽的电化学窗口等。由于离子液体自身较高的电导而避免了加入电解质对电化学反应的干扰,适合于在有机电化学研究中的应用。离子液体作为电化学过程中的替代溶剂,成为发展清洁合成的重要途径。电化学反应通常在常温常压下进行,毒性和危害性都比传统有机合成要小,电化学过程也是清洁技术的重要组成部分。因此,在全球环境问题日益严峻的今天,电化学及其技术将显示其重要作用。本文希望在自行合成离子液体的基础上,利用离子液体取代有机溶剂和支持电解质,探索在有机氧化还原反应中的应用。本工作结合我们实验室的研究兴趣,分别研究了不同离子液体中硝基苯的电化学行为,以及溴代苯酚在不同离子液体中的电化学还原过程,得到了一些初步的结果:1)合成了1-丁基-3-甲基咪唑六氟磷酸盐([Bmim]PF6)离子液体、N-甲基咪唑对甲苯磺酸([Hmim]TsO)离子液体和硫酸乙酯1-乙基-3-甲基咪唑(EMISE)离子液体,并通过核磁氢谱、红外光谱、拉曼光谱等对其进行了表征。2)研究了[Hmim]TsO和[Bmim]PF6中硝基苯的电化学行为。循环伏安测量结果显示,在[Hmim]TsO离子液体中是不可逆的电极过程;扫描速率、温度、浓度对其电化学行为的影响的考察表明,硝基苯在[Hmim]TsO离子液体中其传递系数(α)是0.40,计时电量法求得其扩散系数(D)是3.379×10-6cm2/s。依据实验结果讨论了离子液体的酸碱性对硝基苯电化学还原行为的影响,即离子液体的酸碱性不同导致硝基苯的还原产物不同。3)研究了2,4,6-三溴苯酚在[Bmim]PF6和EMISE离子液体中的电化学还原脱卤行为。循环伏安和脉冲伏安法测量显示,有机卤化物在银电极上还原脱卤的电位比玻碳电极上的更正,而且在同样的实验条件下,可以脱去更多的卤素原子,表明银电极对芳香族卤化物具有电催化能力。更多还原

【Abstract】 As a green alternative solvent, the applications of room temperature ionic liquid have been involved in electrochemistry with electroplating, batteries, organic electrosynthesise, electrocatalysis and capacitive technologies. When it was compared with the traditional organic solvents and electrolytes, ionic liquid has excellent characteristics, such as low melting point, wide liquid temperature range, negligible vapor pressure, high thermal stability, good chemical stability and wide electrochemical window, etc. Because of high conductivity of ionic liquid, which can be used in electrosynthesise to avoid the the influence of electrolyte on the electrochemical reaction. Ionic liquids have become an important way to develop clean synthesis as alternative solvents in the electrochemical process.The electrochemical process has been become an important component of clean technologies, which due to the electrochemical reaction is usually carried out under normal temperature and pressure, toxicity and harmfulness is smaller than traditional organic synthesis. Therefore, in today with the increasingly severe global environmental problems, the important role of electrochemical technology will be demonstrated.In this paper, different ionic liquids have been synthesized by ourself and used them to replace the traditional organic solvents and its application in organic electrochemical redox reactions heve been investigated. This work combined with our lab’s research subject, electrochemical behaviors of nitrobenzene and bromophenol were researched in different ionic liquids at different work electrode and some preliminary results heve been obtained:1) 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6) ionic liquid, N-methyl-imidazole-p-toluenesulfonic acid ([Hmim]TsO) ionic liquid, and sulfuric acid ester 1-ethyl-3-methylimidazolium (EMISE) ionic liquid have been synthesized,and the structure were characterized by 1HNMR, IR and Raman spectroscopy.2) The electrochemical behaviors of nitrobenzene have been investigated in different ionic liqid of [Hmim] TsO and [Bmim]PF6. Cyclic voltammetry measurements showed that it was a irreversible electrode process in [Hmim] TsO. The electrochemical behavior with different scan rate, temperature and concentration of ionic liquid were also investigated. The transfer coefficient (α) is 0.40, diffusion coefficient (D) is 3.379×10-6cm2/s of nitrobenzene in ionic liquids was estimated by chronocoulometry measurement. And the acidity and basicity of ionic liquids have an effect on elecchemical behavior of nitrobenzene. Different products of nitrobenzene reduction can be got when use ionic liquids of different acidity.3) The electrochemical reduction dehalogenation of 2,4,6-tribromophenol in [Bmim]PF6 and EMISE ionic liquid have been investigated. Cyclic voltammetry and pulse voltammetry measurement results showed that the reductive potential of dehalogenation at silver electrode more positive than at the glassy carbon electrode. More halogen atoms can be dehalogenated at silver electrode than at GC electrode with the same experimental conditions. This result indicated that silver electrode has excellent electrocatalytical activity on electrochemical reduction of organo-halogencompounds.更多还原