5－Br－TAPC的合成及其钛（Ⅳ）－5－Br－TAPC－OP显色反应的分光光度研究

SYNTHSIS OF 5-Br-TAPC AND STUDIES ON CHROMOGENIC REACTION OF Ti( IV)- 5-Br-TAPC-OP

合成了４－（５－溴－２－噻唑偶氮）邻苯二酚（５－Ｂｒ－ＴＡＰＣ）显色剂，并用于钛（Ⅳ）显色反应研究。在ｐＨ４．４和ＯＰ存在下，５－Ｂｒ－ＴＡＰＣ与钛（Ⅳ）形成２：１的配合物，其最大吸收波长为５４４ｎｍ，对比度（△λ）１１４ｎｍ，摩尔吸光系数ε６４４为８．６１Ｌ·ｍｏｌ－１·ｃｍ－１，表观稳定常数为４．９８×１０９（２５℃，μ０．１），在０μｇ～１４μｇ钛／２５ｍｌ范围内遵从比耳定律。该法用于钢样的分析取得了满意的结果。

Bromo-2-thiazolylazo)pyrocatechnol(5-Br-TAPC)was Synthesized and used to re act with Ti( Ⅳ) to form Ti(Ⅳ )- 5-Br-TAPC-OP ternary complex at pH 4.4 and in the presence ofOP. The component ratio of the complex formed is l: 2 with the λmax being 544 nm,the contrast(△λ)114 nm,ε544=8.61×104L·mol-1·cm-1 and the apparent stability constant is 4.98×109(25℃,μ0.1).Beer's law is obeyed in the range of O to 14μg of Ti per 25ml.This method Was applied to the spectrophotometric derermination of titanium in alloy steel with satisfactory resule.