DBC-偶氮胂在水溶液中离解作用的研究  

Studies on the Dissociation of DBC-Arsenazo in Aqueous Solution

作　　者：李红[1] 蔡汝秀[1] 曾云鹗[1] Li Hong;Cai Ruxiu;Zeng Yun’e(Department of Chemistry,Wuhan University,Wuhai)

机构地区：[1]武汉大学化学系

出　　处：《高等学校化学学报》1986年第8期686-688,共3页Chemical Journal of Chinese Universities

摘　　要：3-(2-胂酸基苯偶氮-6-(2,6-二溴-4-氯苯偶氮)-4,5-二羟基-2,7-萘二磺酸)(简称DBC-偶氮胂)可在高酸度下(0.2-1.7NHCl)与稀土元素发生灵敏显色反应,且选择性非常好,前文已报导用该试剂直接光度测定高温合金中微量铈。本文研究了DBC-偶氮胂在水溶液中的离解作用,用pH电位法及分光光度法测定DBC-偶氮胂及各级条件离解常数,结果表明:由于多卤素原子的引入,使试剂更易于质子化;因而离解常数比偶氮胂Ⅲ大。The dissociation of DBC-Arsonazo in aqueous solution was studied by spectro-phtometric and potentiometric litration meiricdr.The values of dissociation constants,pK1=0.70,pK2=1.68,pK3=2.76,pK4=6.54,pK5=9.64,pK6=10.54,were determined by spectrophotorr.ctric methods at the identical temperature and ionic strength(20℃,I=0.4).Under the identical conditions the results pK3=3.7,pK4=6.67,pK5=9.95,pK6=10.95,obtained by using the potentiometric titration method.

关 键 词：离解常数 卤素原子 PH电位法 偶氮胂Ⅲ 离解作用 显色反应 质子化 分光光度法测定 

分 类 号：O65[理学—分析化学]