取代喹啉杂环碱在水中质子化作用平衡常数的测定

前文我们对取代吡啶杂环碱在水中质子化作用平衡常数进行了测定^[1]。本文利用和前文相同的方法测定了具有不同取代基喹啉碱类的平衡常数^[2]。发现如果喹啉某位的氢被吸电子基团取代,则喹啉碱的平衡常数减小,而被给电子基团取代,则喹啉碱的平衡常数增大。这样对探讨这些基团的电子效应是有实际意义的。

THE DETERMINATION OF EQUILIBRIUM CONSTANTS Keq FOR PROTONATION OF SUBSTITUTED QUINOLINES IN AQUEOUS SOLUTION

In the previous paper the equilibrium constants Keq for protonation of substituted pyridine bases in aqueous solution have been determined. In this paper the equilibrium constants Keq of various substituted quinolines hare been determined with the same method.The experimental results showed that the equilibrium constants of quinol-ine bases were decreased or increased,when certain hydrogen on thfe quinoline ring was substituted with electron-attracting groups or electron-donating groups respectively. Thus, the electronic effect of substituents can be deduced from the Keq values.