螯核羧酚电离常数的测定及在水溶液中解离状况的研究

STUDIES OF DISSOCIATION OF QUINAMIC ACID IN AQUEOUS SOLUTION

本文运用UV、~1H-NMR等手段研究了螯核羧酚(QNA)在水溶液中的解离状况,认为QNA在pH 10.5以下可作为七元酸处理。并用电位法测出了各级酸解离常数,得到了ONA在水溶液中的物种分布图。探讨了QNA作为金属促排剂在体内作用的机制。

The dissociation of quinamic acid (QNA) in aqueous solution has been studied by UV and 'H-NMR etc. There are eighteen sites binding protons on the basis of molecular structure, but QNA is a seven-basic acid under pH10.5. Its acidic dissociation constants were determined by potentiom-etric method, and gave a species distribution plot of QNA in aqueous solution. At 25.0 + /-0.1℃ and 1 = 0.1 (KNO3), the dissociation constants (pKi) of QNA are: 2.79 + /-0.06, 3.74 + /-0.04, 5.88 + /-0.02, 6.93+/-0.03, 7.90+/-0.03, 9.16 + /-0.02, 9.56 + /-0.05. As a metallic detoxic agent, the mechanism of QNA acting in the human body has been discussed.