高等学校化学学报

高等学校化学学报 ›› 1986, Vol. 7 ›› Issue (8): 686.

• 研究简报 • 上一篇    下一篇

DBC-偶氮胂在水溶液中离解作用的研究

李红, 蔡汝秀, 曾云鹗   

  1. 武汉大学化学系
  • 收稿日期:1985-05-04 出版日期:1986-08-24 发布日期:1986-08-24

Studies on the Dissociation of DBC-Arsenazo in Aqueous Solution

Li Hong, Cai Ruxiu, Zeng Yun'e   

  1. Department of Chemistry, Wuhan University, Wuhai
  • Received:1985-05-04 Online:1986-08-24 Published:1986-08-24

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被引次数

14

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sup>[1]。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。

Abstract: 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.

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