钼(Ⅵ)-4-(5-溴-2-噻唑偶氮)邻苯二酚-二苯胍三元离子缔合物的萃取分光光度研究

Studies on Extraction Spectrophotometry of Ternary Molybdenum(Ⅵ) 4 (5 Bromo 2 Thiazolylazo) Pyrocatechol Diphenyl Guanidine Ion Associate

在ｐＨ４．０的介质中，Ｍｏ（Ⅵ）与新试剂４－（５－溴－２－噻唑偶氮）邻苯二酚（５－Ｂｒ－ＴＡＰＣ）和二苯胍（ＤＰＧ）反应形成稳定的三元离子缔合物，其组成比Ｍｏ（Ⅵ）：５－Ｂｒ－ＴＡＰＣ∶ＤＰＧ为１∶３∶２。该三元缔合物氯仿萃取液的λｍａｘ为５３６ｎｍ，对比度为１１９ｎｍ，表观ε为６．３３×１０４Ｌ·ｍｏｌ－１·ｃｍ－１。钼（Ⅵ）含量在０～０．８０ｍｇ／Ｌ范围内遵从比耳定律，并探讨了离子缔合物的结构。将在最佳显色条件下拟定的分析方法用于合金钢中小量或痕量钼的测定，取得了满意的结果。

4 (5 Bromo 2 thiazolylazo)pyrocatechol(5 Br TAPC),a new reagent,reacts with Mo(Ⅵ) and diphenyl guanidine(DPG) to form a stable violet red neutral ternary ion associate in a medium of pH4.0.The ratio among Mo(Ⅵ),5 Br TAPC and DPG is 1∶3∶2 in the associate with λ max of 536nm,contrast 119nm and apparent mole absorptivity of 6 33×10 4L·mol -1 ·cm -1 for the chloroform extract of the ternary ion associate.Beer's law is obeyed in the range of 0 to 0.80mg of Mo(Ⅵ) per liter.The structure of the ion associate was discussed.Satisfactory results have been achieved in applying the method to the determination of minor or trace molybdenum in alloy steel.