分析量子化学研究(Ⅱ)——光度分析新显色剂对甲基偶氮氯膦离解与质子化作用及其机理

Studies on Analytical Quantum Chemistry(Ⅱ)——The Protonation and Dissociation of a New Chromogcnic Reagent-Chlorophosphonazo-p-Methyl and Their Mechanism

对甲基偶氮氯膦(CPApM)作为不对称偶氮氯膦类光度分析显色剂,已应用于稀土氧化物与有关矿石、镍基合金中测定钇的含量,本文以分光光度法测得了CPApM的离解常数及质子化常数,运用HMO法进行半经验量子化学计算,并对其电子结构、离解作用与质子化作用及微观机理作了探讨。

The protonation and dissociation of chlorophosphonazo-p-methyl(CPApM) in aqueous solution have been studied spectrophotometrically. The protonation constant (lgKp) was found to be -0. 158±0. 005 and the dissociation constant (pKa) 11. 41 ± 0. 03. The electronic structure of CPApM and microcosmic mechanism of protonation and dissociation of the reagent are interpreted by the calculation with quantum chemistry.