【作者】 陆娜萍；

【导师】 李在均；

【作者基本信息】 江南大学 ， 分析化学， 2008， 硕士

【摘要】 建立稀散金属高灵敏检测方法和适合湿法冶金的绿色萃取体系具有现实意义。基于荧光酮类试剂结构与性能关系的规律性研究,成功设计合成一种新荧光酮试剂-对甲氧基苯基偶氮水杨基荧光酮(p-MOPASF)。合成对甲氧基苯基偶氮水杨醛中间体,并对其进行元素分析,再与偏苯三酚三乙酯缩合得p-MOPASF,试剂总产率为41%;采用紫外(UV)、红外(IR)和电喷雾质谱(EIS)对试剂进行了结构表征;提出离子液体绿色工艺路线,成功应用于1-辛基-3-甲基咪唑六氟磷酸盐离子液体([C8mim][PF6])的合成。以钼、钨、锗、镓、铟五种金属元素作为稀散金属的代表,分别研究了p-MOPASF与钼、钨、锗、镓和铟的显色反应。在硫酸介质和十六烷基三甲基溴化铵(CTMAB)存在下,p-MOPASF与钼和钨均发生灵敏的显色反应,均形成配位比为3:1的橘红色配合物,配合物的最大吸收波长分别为526nm和519nm,表观摩尔吸光系数分别可达1.43×105 L·mol-1·cm-1和1.36×105L·mol-1·cm-1。钼(VI)和钨(VI)含量分别在0~15μg/25mL和0~30μg/25mL内符合比尔定律。此外,继续研究了p-MOPASF与锗的显色反应。在磷酸介质和聚乙二醇辛基苯基醚(OP)存在下,p-MOPASF与锗发生灵敏的显色反应,形成配位比为3:1的橘红色配合物,配合物的最大吸收波长为507nm,表观摩尔吸光系数达1.44×105L·mol-1·cm-1,0~2.5μg/25mL锗(IV)符合比尔定律。在此基础上,我们进一步研究了p-MOPASF与镓和铟的显色反应。在NaAc-HAc缓冲溶液和CTMAB存在下,p-MOPASF与镓和铟均发生灵敏的显色反应,均形成配位比为3:1的红色配合物,配合物的最大吸收波长分别为558nm和559nm,表观摩尔吸光系数分别可达1.23×105 L·mol-1·cm-1和1.68×105L·mol-1·cm-1,镓(III)、铟(III)含量均在1~10μg/25mL内符合比尔定律。从上面数据可以看出,对甲氧基苯基偶氮水杨基荧光酮是一种优良的螯合剂,可用于稀散金属的分析和湿法冶金等领域。尽管p-MOPASF与稀散金属的显色反应具有较高灵敏度,但对复杂样品中超痕量测定仍显不足。为了进一步提高方法灵敏度,采用离子液体替代易挥发的有机溶剂作为萃取介质,应用于稀散金属的液-液萃取。本文选择萃取效率高、相分离速率快的[C8mim][PF6]作为萃取剂。在1000mL容量瓶中,钼、钨、锗、镓和铟与p-MOPASF形成稳定的配合物后,向体系中加入5mL[C8mim][PF6],振荡5min,配合物迅速进入离子液体相。在离子液体相中加入一定体积的丙酮溶液稀释,再加入适量的活性炭吸附,剧烈振荡5min后向活性炭相中加入4.0mol/LNaOH溶液,分出的水相由光度法测定钼、钨、锗、镓、铟的含量。本课题重点讨论了钼的萃取体系,该方法应用于环境水样中超痕量钼的测定,钼的萃取率和反萃率均较高,同时结合原子吸收光谱法进行了测定,结果令人满意。离子液体是一种绿色溶剂,用它替代湿法冶金中使用的大量有机溶剂,从而可消除由有机溶剂挥发而产生的环境污染。我们还进一步研究了锗的萃取体系。该萃取体系应用于模拟的锌电解液中锗的回收尝试,萃取率和反萃率均取得了较满意结果。更多还原

【Abstract】 Research new methods on determination of trace rare metals with better sensitivity and development of rare metals with green extaction system on metallurgy industry are very important increasingly. Based on the consideration of the relationship of the structure of phenylfluorone reagents and their analytical characteristics, a new reagent, 5-p-methoxyphenylazosalicylfluorone (p-MOPASF), was designed and synthesized in this laboratory. Firstly, element analysis was applied to confirm the intermediate of 5-p-methoxyphenylazosalicylaldehyde. The 5-p-methoxyphenylazosalicylaldehyde reacted with 1,2,4-triacetoxybenzene and then p-MOPASF can be obtained by condensation and the product ratio can be up to 41%. After purified, the molecular structure of the reagent was confirmed by ultraviolet spectrum (UV), infrared spectrum (IR) and EIS-/EIS+. The green process route with ionic liquid was developed and 1-octyl-3-methyl-imidazolium hexafluorophosphate ionic liquid was also synthesized successfully.Molybdenum, tungsten, germanium, gallium and indium were choiced as representatives of rare metals. Firstly, we investigated color reaction of p-MOPASF with molybdenum tungsten, germanium, gallium and indium, respectively. In the presence of sulfuric acid and CTMAB, p-MOPASF reacted with molybdenum and tungsten rapidly to form 3:1 orange complex with the maximum absorption peaks at 526nm and 519nm, respectively. The apparent molar absorptivity were found to be 1.43×105L·mol-1·cm-1 and 1.36×105L·mol-1·cm-1, respectively. Beer’s law is obeyed in the range of 0~15μg/25mL and 0~30μg/25mL for molybdenum and tungsten, respectively. Furthermore, we also studied the color reaction of p-MOPASF with germanium. In the presence of phosphate acid and OP, p-MOPASF reacted with germanium rapidly to form 3:1 orange complex with the maximum absorption peak at 507nm. The apparent molar absorptivity was found to be 1.44×105L·mol-1·cm-1. Beer’s law is obeyed in the range of 0~2.5μg/25mL for germanium. Moreover, on the basis of above color reaction between p-MOPASF and rare metal ions, we studied the color reaction of p-MOPASF with gallium and indium. In the presence of NaAc-HAc buffer solution and CTMAB, p-MOPASF reacted with gallium and indium rapidly to form 3:1 red complex with the maximum absorption peaks at 558nm and 559nm, respectively. The apparent molar absorptivity were found to be 1.23×105L·mol-1·cm-1 and 1.68×105L·mol-1·cm-1, respectively. Beer’s law is obeyed in the range of 0~10μg/25mL for gallium and indium. Based on the above datas, 5-p-methoxyphenylazosalicylfluorone is a new chelator and can be employed on rare metals on analysis and on metallurgy industry.Although color reaction of p-MOPASF with rare metal ions have high sensitivity, the methods are not good enough to determine ultra trace Mo, W, Ge, Ga and In in complicated samples. In order to advance the sensitivity further more, room temperature ionic liquid was used to replace traditional volatile organic reagents in liquid-liquid extraction of molybdenum, tungsten, germanium, gallium and indium. 1-octyl-3-methylimidazolium hexafluorophosphate [C8mim][PF6] with high extraction efficiency was chosen as medium. After the complex of molybdenum, tungsten, germanium, gallium and indium with p-MOPASF were formed in optimal conditions in 1000mL calibrated bottle, 5mL [C8mim][PF6] were added into the solution and the complex were extracted to ionic liquid phase after 5 minutes’surge. A certain volume of acetone and some amount of activated carbon were added into the ionic liquid phase with 5 minutes’surge. The complex was back-extracted by 4.0mol/LNaOH solution and then molybdenum, tungsten, germanium, gallium and indium in water phase were determined by spectrophotometry. We focused on the extraction system of molybdenum, and the method was chosen and applied to determine ultra trace molybdenum in environmental water samples. Combined by graphite furnace atomic absorption spectrometry, both the extraction efficiency and stripping efficiency were very high, and the results are satisfying. Ionic liquids are“green reagents”. In order to avoid environmental pollution caused by organic reagents’volatilization, they can be used to replace traditional organic reagents in hydrometallurgy. Furthermore, the extraction system of germanium was also studied and the system was suitable to enrich germanium from simulated hydrometallurgical zinc electrolyte. It is proved that the results are satisfying.更多还原