新显色剂5-(5-碘-2-吡啶偶氮)-2,4-二氨基甲苯与铑(Ⅲ)高灵敏显色反应的研究及其应用  

Synthesis of 5-(5-Iodine-2-pyridylazo)-2,4-diaminotoluene and Its Color Reaction with Rhodium(Ⅲ)

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

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

出　　处：《分析科学学报》2010年第2期162-166,共5页Journal of Analytical Science

基　　金：西安市科技计划项目(CXY09015-5)

摘　　要：合成了新试剂碘代吡啶偶氮胺类化合物5-(5-碘-2-吡啶偶氮)-2,4-二氨基甲苯(5-I-PADAT),用红外光谱、元素分析和核磁共振波谱对其进行了鉴定,并研究了该试剂与铑(Ⅲ)的显色反应。结果表明,在pH=4.0～5.2的乙酸-乙酸钠缓冲溶液中,铑(Ⅲ)与5-I-PADAT形成1∶2的紫红色络合物。该络合物在1.2mol·L-1高氯酸介质中转变为另一稳定的蓝色配合物,其最大吸收峰位于580nm波长处,铑(Ⅲ)含量为0～0.8μg/mL范围内符合比耳定律,表观摩尔吸光系数为1.81×105L·moL-1·cm-1。该反应具有很高的灵敏度和良好的选择性,大量常见金属离子在一定范围内无干扰。所拟方法操作简单,用于催化剂中微量铑的测定,结果满意。A new reagent,5-（5-iodine-2-pyridylazo）-2,4-diaminotoluene（5-I-PADAT）has been synthesized,and characterized by infrared spectroscopy,elemental analysis and nuclear magnetic resonance spectroscopy. The color reaction of 5-I-PADAT with rhodium（Ⅲ） was studied. The experimental results show that rhodium（Ⅲ）reacts with 5-I-PADAT at the pH range of 4.0~5.2 to form a violet-red complex and its maximum absorbance is at 580 nm. The molar ratio of Rh（Ⅲ）to 5-I-PADAT is 1：2. The complex changes into a blue one in 1.2 mol／5L-1 HClO4 acid solution with an apparent molar absorptivity of 1.81×105 L／5moL-1／5cm-1 and Beer＇s law is obeyed in the range of 0~0.8 μg/mL for rhodium. The method is highly sensitive and selective and has been successfully applied to the determination of trace rhodium in catalysts with satisfactory results.

关 键 词：5-(5-碘-2-吡啶偶氮)-2 4-二氨基甲苯 铑 分光光度法 

分 类 号：O657.32[理学—分析化学]