多卤代变色酸双偶氮类稀土显色剂的合成及分子结构与吸光性能的关系

Studies on the Synthesis of Rare Earth Color Reagents of Polyhalogenated of Bisazo Type and the Relationship Between Their Molecular Structures and Properties

本文设计、合成了一类新型稀土显色剂——多卤代变色酸双偶氮衍生物,它们易溶于水、乙醇和丙酮,不溶于苯、己醚和氯仿,是具有高灵敏度、高选择性、显色酸度高、空白值低的优良稀土显色剂,本文还研究了试剂的分子结构和吸光性能的关系,当助色基及其取代位置一定时,具有—AsO_(3)H_(2)、—COOH、—PO_(3)H、—Cl络合功能基的性质,其灵敏度较高。

In this parper, a sort of new rare earth color reagent-polyhalogenated bisazo chromotropic acid derivcnts have been designed and synthesized. They are easily soluble in water, alcohol and acelone, but insoluble in benzene, ether and chloroform. The absorption maxima of arscnazo or carboxyazo types reagents are at about 527-540nm and chlorophosphonoazo type at 543-549nm. The absorption maxima of the complexes of reagents with rare earth elements are at 628-650nm.The color reagents can react with rare earth elements not only in weak acidic medium (pH = 2-5), but also in strong acidic solution (such as 0.1-4N HCl, H_(2)SO_(4), HClO_(4) and H_(5)PO_(4)). The sensitivity of polyhalogenalcd bisazo reagents is higher than other reagents of the same type. The molar absorptivity (ε_(Ce)) can reach 1.2-1.4×10^(5).Bccase of high acidity of color reaction and sterically hindered effect of poly-halogenated auxochrome groups, the seletivity is increased greatly. The tolerant uantity of ordinary elements can reach several or tens milligrams, especially for alkali-earth and alloying elements Ni and Cr.In the parpcr, the relationship between molcular structures of the reagents and their properties have also been studied. When the auxochrome groups and their positions of reagents are fixed, the sensitivity of reagents with complex function groups -AsO_(3)H_(2);-COOH;-PO_(3)H_(2), -Cl and arc the highest.