试剂DNPDADP的合成及其与氯化十六烷基吡啶显色反应的研究

Synthesis of a Reagent DNPDADP and Study on its Color Reaction with Cetylpyridinium Chloride

本文合成试剂4,4′-二(4-硝基苯基重氮氨基)联苯(DNPDADP),研究该试剂与阳离子表面活性剂氯化十六烷基吡啶(CPC)的显色反应及机理.建立分光光度测定阳离子表面活性剂CPC的新方法.结果表明,在pH12.5碱性介质中,试剂与CPC形成1:2紫红色离子缔合物,最大吸收波长位于525 nm处,表观摩尔吸光系数为1.69×104L·mol^(-1)·cm^(-1).表面活性剂的浓度在1.0×10^(-6)~1.2×10^(-5)mol/L范围内符合比耳定律.该方法直接应用于水样中氯化十六烷基吡啶的测定,结果满意.

The method of synthesis for 4,4′-Di（4-nitrophenyldiazoamino） diphenyl and the color reac-tion between the reagent and cetylpyridinium chloride have been studied. The results show that in themedium of pH12.5,DNPDADP reacts with CPC to form a purple-red ion pair complex with the mo-lar ratio of 1：2,The ion pair complex exhibits maximum absorption at 525 nm with a molar absorptivi-ty of 1.69×10^4L·mol^-1·cm^-1. Beer＇s law is obeyed in the range of 1.0×10^-6～1.2×10^-5mol/L. The meth-od has been applied to the determination of micro CPC in water sample with satisfactory results.