2-(5-碘-2-吡啶偶氮)-5-二甲氨基苯胺的合成及其与铑(Ⅲ)的高灵敏显色反应的研究  

Synthesis of a New Reagent 2-(5-Iodine-2-pyridylazo)-5-dimethylaminoaniline and Its Color Reaction with Rhodium

作　　者：韩权[1,2] 霍燕燕[1] 刘渊[1] 杨晓慧[1] 高美娟[2] 

机构地区：[1]西安文理学院化学与化工系,陕西西安710065 [2]延安大学化学与化工学院,陕西延安716000

出　　处：《分析测试学报》2010年第8期797-801,共5页Journal of Instrumental Analysis

基　　金：西安市科技计划资助项目(CXY09015-5)

摘　　要：合成了新显色剂2-（5-碘-2-吡啶偶氮）-5-二甲氨基苯胺（5-I-PADMA），并研究了其与铑（Ⅲ）的显色反应。结果表明，在pH4．0～6．2的乙酸-乙酸钠缓冲介质中，铑（Ⅲ）与5-I—PADMA可形成稳定的1：2配合物，该配合物呈现2个吸收峰，分别位于557、597nm处。配合物形成后，以适量HClO4（0．24～5．57mol·L^-1）酸化，可转变为另一种具有较高吸收特性的质子化形体，其吸收峰分别红移至564、613nm处。表观摩尔吸光系数达％，=1．86×10^5L·mol^-1·cm^-1，铑的质量浓度在0～0．56mg·L^-1范围内符合比尔定律。该法是目前测定痕量铑的高灵敏显色体系之一，且具有良好的选择性。所建立的方法操作简单，应用于催化剂中微量铑的测定，结果满意。A new chromogenic reagent 2-（5-iodine-2-pyridylazo ） -5-dimethylaminoaniline （ 5-I-PAD- MA） was synthesized and characterized by infrared spectroscopy, elemental analysis and nuclear magnetic resonance spectroscopy. The color reaction of 5-I-PADMA with rhodium（ m ） was investiga- ted. The experimental results showed that, in pH 4.0 - 6. 2 HAc - NaAc buffer, rhodium （ Ⅲ ） could react with 5-I-PADMA to form a stable 1 ： 2 complex, which had two absorption peaks at 557 nm and 597 nm, respectively. When the complex was acidified by suitable amount of HCIO, （0. 24 - 5.57 mol · L^- 1 ） , it could be changed into a new species possessing a higher abosorption characteristics and its two absorption peaks were shifted to 564 nm and 613 nm, respectively. The apparent molar absorptivity was 1.86 × 10^5 L ·mol^-1· cm^-1 at 613 nm and Beer＇s law was obeyed in the range of 0 -0. 56 mg · L^-1 for rhodium. The method was highly sensitive and selective, and was applied in the determination of trace rhodium in catalysts with satisfactory results.

关 键 词：2.(5-碘-2-吡啶偶氮-5-二甲氨基苯胺 合成 铑 分光光度法 

分 类 号：O657.32[理学—分析化学] O614.822[理学—化学]