Janjić T J, Pfendt L B, Aleksić M B
Faculty of Chemistry, University of Belgrade, P.O., Box 550, 11001 Belgrade, Yugoslavia.
Talanta. 1992 Jan;39(1):55-62. doi: 10.1016/0039-9140(92)80050-n.
Heterogeneous equilibria in saturated aqueous solutions of 8-hydroxyquinoline (A), 2-methyl-8-hydroxyquinoline (B) and 5-chloro-8-hydroxyquinoline (C) were investigated at constant ionic strength (1M sodium chloride), at 25.0 +/- 0.1 degrees , by the application of the following methods: the formation function method, the method of bound protons, the method of free proton sites and the solubility method. The following equilibrium constants were determined: K(s1)=[H(2)A(+)]/[H(3)O(+)], K(s2)=[HA] and K(s3)=[H(3)O(+)] [A(-)]. Their mean pK values are: -2.88, 2.42 and 12.09 for A, -3.27, 2.71 and 12.73 for B, and -0.34, 3.88 and 12.75 for C. In addition, the acidity constants of investigated 8-hydroxyquinolines were determined by pH-metric titrations. The values obtained for these constants were consistent with those calculated on the basis of corresponding equilibrium constants determined in heterogeneous systems.
在25.0±0.1摄氏度、恒定离子强度（1M氯化钠）条件下，采用以下方法研究了8-羟基喹啉（A）、2-甲基-8-羟基喹啉（B）和5-氯-8-羟基喹啉（C）饱和水溶液中的多相平衡：生成函数法、结合质子法、自由质子位点法和溶解度法。测定了以下平衡常数：K(s1)=[H(2)A(+)]/[H(3)O(+)], K(s2)=[HA] 和 K(s3)=[H(3)O(+)] [A(-)]。它们的平均pK值分别为：A为-2.88、2.42和12.09；B为-3.27、2.71和12.73；C为-0.34、3.88和12.75。此外，通过pH滴定法测定了所研究的8-羟基喹啉的酸度常数。这些常数所得到的值与基于在多相体系中测定的相应平衡常数计算得出的值一致。
