显色剂2-苯并噻唑偶氮-7-(4-甲氧基苯偶氮)-1,8-二羟基萘-3,6-二磺酸的合成及与铁(Ⅲ)显色反应研究

STUDY ON THE SYNTHESIS OF 2-(BENZOTHIAZOLYLAZO)-7-(4- METHOXYPHENYLAZO)-CHROMOTROPIC ACID AND ITS COLOR REACTION WITH IRON(Ⅲ)

合成了一种新的杂环不对称双偶氮变色酸试剂2 苯并噻唑偶氮 7 (4 甲氧基苯偶氮) 1,8 二羟基萘 3,6 二磺酸(简称BTAMOPACA)。研究了试剂的结构和光度性质,结果表明,在pH6.0的邻苯二甲酸氢钾 氢氧化钠缓冲介质中,铁(Ⅲ)与BTAMOPACA及CTMAB形成1∶2∶1的三元配合物,其最大吸收波长为690nm,表观摩尔吸光系数ε=1.19×105L·mol-1·cm-1,在0～5μg/25ml范围内符合比耳定律,建立了测定石灰石和高炉渣中铁的方法,结果满意。

A new chromogenic reagent, 2-(benzothiazolylazo)-7-(4-methoxyphenylazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid (abbreviated as BTAMOCA) was synthesized and its molecular structure was proved by IR-spectrometry,()~1HNMR-spectrometry and elementary analysis. The dissociation constants of the reagent as a tetrabasic acid was determined. The result of study of its photometric behavior showed that in a hydrogen phthalate buffer medium of pH 5.8～6.4, a ternary complex of the reagent with Fe(Ⅲ) and CTMAB in the mole ratio of 2∶1∶1 is formed with its absorption maxima at the wavelength of 690nm and its apparent molar absorptivity (ε) of 1.19×10~5L·mol^(-1)·cm^(-1). Beer′s law holds in the range of 0～5μg of Fe(Ⅲ) per 25ml of solution. This method has been satisfactorily applied to the analysis of limestone and blast furnace slag.