Color Reaction of 5-(4′-Bromo-2′-carboxyphenylazo)rhodanine With Copper and Its Application
Wang Lun; Zhu Changqing; Mao Lanqun; Shi Haoxin (Department of Chemistry, Anhui Normal University, Wuhu 241000)
The synthesis of a color reagent 5-(4' -bromc-2' -carboxyphenylazo ) rhodanine was described. The dissociation constants of the reagent Ka1 and Ka2 are given. The color re action of the reagent with Cu(Ⅱ ) is studied. The molar ratio of Cu(Ⅱ ) to the reagent is 1: 2. The Beer' s law is obeyed in the range of 0~ 2. 7 mg/L for Cu (Ⅱ ) with of 8. 9× 104L· mol -1. cm -1. The method has been applied to the determination ot copper in alloy sample with satisfactory results.