Study On Synthesis Of Triazene Reagents And Their Complexing Reactions With Toxic Thallium

Thallium, which has been listed among the USEPA's 13 priority metals, is an element with great accumulative toxicity and poses a significant potential threat to the ecosystem. In this paper, we hope to develop a quick, cheap and reliable method for the determination of thallium in areas with moderate contamination of it, so that our work can promote relative departments to make guidelines and environmental standards for thallium earlier. Furthermore, we still hope the study on the relationship between molecular structure of the triazene reagents and their analytical properties can be helpful theoretically in designing and synthesizing more better reagents.At present, the study and application of the triazene reagents have extended from the domain of traditional inorganic analysis to the life active substance and environment contamination analysis. Derivatives of benzenediazoaminoazobenzene are one kind of triazene reagents. Containing triazenediyl group, they can react with many metal ions to form micellar complex with high sensitivity in alkaline medium in the presence of suitable surface active agent. For this, they are used for the spectrophotometric determination of trace metal ions simply, rapidly and accurately. Due to their wider application fields and the increase of the synthetic number, the reagents have caused great interest among researchers. The general structure of the reagents is as follows:The 14 derivatives of benzenediazoaminoazobenzene were synthesized by coupled reactions of diazotizing-substituted anilines with p-aminoazobenzene in weak acidic medium, and the mechanism of reactions was discussed too. From the conclusion of their color reactions with thallium, it is found that o-MDAA and DMDAA reagents give the most sensitivity. The purified compounds were obtained by the ways of recrystallization or column chromatography; infrared spectrum and elemental analysis were employed to confirm their structures and all the results were...