新显色剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯的合成及其与钯的显色反应

合成并用红外光谱和元素分析鉴定了氟代吡啶偶氮氨类新试剂5-(5-氟-2-吡啶偶氮)-2,4-二氨基甲苯(5-F-PADAT),并研究了该试剂与钯显色的反应。结果表明,在0.32~3.84 mol/L高氯酸溶液中,试剂与钯形成1∶1的紫红色络合物,其最大吸收峰位于566 nm,表观摩尔吸光系数为4.84×104L.mol-1.cm-1,钯的浓度在0~2000μg/L符合比耳定律。方法选择性好,大量常见金属离子不干扰钯的测定,操作简单,应用于矿样和催化剂中微量钯的测定,结果与原子吸收光谱法相符。

Synthesis of 5-(5-Fluoro-2-Pyridylazo-)-2,4-Diaminotoluene and Its Chromogenic Reaction with Palladium

A new chromogenic reagent 5-(5-fluoro-2-pyridylazo)-2,4-diaminotoluene(5-F-PADAT) has been synthesized and characterized by infred spectometry and elemental analyzer.The chromogenic reaction of 5-F-PADAT with palladium(Ⅱ) was also studied.The experimental results show that Pd(Ⅱ) reacts with 5-F-PADAT to form a stable violet-red complex in a solution of 0.32～3.84 mol/L HClO4.The molar ratio of Pd(Ⅱ) to 5-F-PADAT is 1∶1 with apparent molar absorptivity of 4.84×104 L·mol-1·cm-1 at the maximum absorption of 566 nm.Beer′s law is obeyed in the range of 0～2000 μg/L for palladium.The method provides high selectivity and most common ions do not interfere with the determination of Pd(Ⅱ).The method has been successfully applied to the determination of micro-amount of palladium in ore and catalyst samples.The results are in agreement with those obtained by atomic absorption spectrometry.