STUDIES ON THE DISSOCIATION OF THE RARE-EARTH CHROMOGENIC REAGENT CHLOROPHOSPHONAZO-mA

作     者：Zhao Hong,Zhu Chuanzheng,Zhou Weiliang and Pan Jiaomai (Department of Chemistry,East China Normal University,Shanghai) Zhao Hong,Zhu Chuanzheng,Zhou Weiliang and Pan Jiaomai (Department of Chemistry,East China Normal University,Shanghai)

出 版 物：《Chemical Research in Chinese Universities》 (高等学校化学研究（英文版）)

年 卷 期：1986年第4卷第1期

页      面：55-64页

学科分类：07[理学] 0703[理学-化学] 

主　　题：STUDIES ON THE DISSOCIATION OF THE RARE-EARTH CHROMOGENIC REAGENT CHLOROPHOSPHONAZO-mA OC 口口 than 

摘      要：Chlorophosphonazo-mA [2-(4-Chloro-2-phosphonobenzenenazo)-7-(3-ac-etylbenzenenazo)-1,8-dihydroxynaphthalene-3,6-disulfonic acid] is a derivative of *** bisazo chromotropic acid,with the following structureIn 1979,it was first reported that the title compound could be used in the spectro determination of the total amount of micro rare-earths existing in spherical graphite cast iron and weak alloy steel and direct spectro determination of the total amount of the rare-earths and the fractional amount of the light and heavy rare-earths when used together with chlophosphonazo-mN It is a rather ideal chromogenic reagent to determine the total amount of the *** was also discovered in later work to be usefulin the spectro determination of the elements uranium(VI)and calciumetc[3,4]In order to make a further study for the thermodynamic properties and kinetic characteristics of the reagent when complexing with the rare-earths we have first investigated the ionization of the chlorophosphonazo-mA in *** paper reports the results of determining the successive ionization constants and the thermodynamic parameters of each step of chlorophosphonazo-mA by pH potentiometric and spectrophotometric methods