四氢咔唑酮离解常数的光度法测定

Spectroscopic determination and theoretical calculation of the dissociation constant of 4-hydroxy carbazole

研究了四氢咔唑酮在不同比例的乙醇-水混合溶剂中及不同酸度下的吸收光谱,提出了采用紫外分光光度法测定四氢咔唑酮在水中离解常数的方法。试验证明:在不同比例的乙醇-水混合溶剂中,四氢咔唑酮的离解常数与乙醇的体积分数存在良好的线性关系,通过外推至乙醇含量为零,可求得在实验条件下四氢咔唑酮在水溶液中的离解常数pKb为14.04。

The dissociation constant of 4-hydroxy carbesole was determined by the spectrophotometric method based on ：tbe absorption spectra of 4-hydroxy earbasole at different pH Values in an ethanol-water mixed solvent.The results showed that the pKb was a good linear function of the volume fraction of ethanol in the concentration range studied. The dissociation constant of 4-hydroxy carbezole in water was determined to be 14.04 by means of extrapolation to a zero concentration of ethanol under the spoeifled conditions of this experiment.