混合表面活性剂对某些吡啶偶氮试剂显色反应的作用

本文研究了表面活性剂对不同电子结构的三种金属离子(Zn~(2+),Cu~(2+),Pd~(2+))与两种分子结构类似但反应官能团不同的吡啶偶氮染料(PAR和5-Cl-PADAB)间的显色反应的作用。试验证明:(1)表面活性剂对显色反应增敏作用的产生,最根本的是由于金属离子的电子结构和试剂的反应官能团的不同,以及由此引起所成显色络合物的结构的不同。(2)表面活性剂对显色络合物的增敏效应,与单个表面活性剂分子对有色络合物的作用有关,更重要的是形成胶束,改变反应微环境。(3)离子型-非离子型混合表面活性剂对显色反应是否产生协同增敏效应和协同增敏效应的大小,决定于两者形成混合胶束的难易。如果显色络合物的结构有利于此两种表面活性剂同时对它起协同作用,则协同增敏效应可进一步提高。

On the Effect of Mixed Ionic and Nonionic Surfactants on the Colour Reactions of Some Metal-pyridylazo-dye Systems

The effects of surfactants on the colour reactions between three metal ions Zn2+, Cu2+ and. Pd2+ with different electronic configuration and two pyridylazo dyes with different function groups are investigated. It is deduced: (1) The sensitization effect of surfactants essentially depends on the structure of the coloured complexes formed from the metal ions with the dyes used. (2) The sensitization effects of the surfactants can be induced by the micellar solubilization and the formation of stoichiometric ternary complexes involving the surfactant monomers. The former mechanism is more important because it serves a novel microenvironment of the colour reaction concerned. (3) The occurence and degree of synergistic senzitization effect of mixed ionic and nonionic surfactants on the colour reaction primarily result from the formation of mixed micelles. The effect may be enhanced if the structure of the coloured complex is favorable to the reaction with both of the surfactants used.