Hydration equilibria of 9-acridinecarboxaldehyde
Hydration equilibria of 9-acridinecarboxaldehyde
复制标题
9-吖啶甲醛的水合平衡
DOI：
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发表时间：
1994
期刊：
影响因子：
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通讯作者：
P. E. Sørensen
中科院分区：
文献类型：
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作者：
R. McCLELLAND;P. Sukhai;K. Engell;P. E. Sørensen
测定了9-吖啶甲醛在水溶液中的水合速率常数和平衡常数。在吖啶被质子化的酸性条件下，水合物和游离醛形式的信号可以在1H NMR光谱中作为单独的物质观察到。积分提供水合平衡常数。使用从光谱滴定曲线获得的表观酸度常数，拟合速率-pH曲线以提供中性吖啶平衡的水合常数，KH = 0.07。 该分析还提供了两种吖啶鎓离子的酸度常数，pK = 3.78的醛和pK = 5.36的水合物。 与4-pyridinecarboxaldehdye系统的比较表明，吖啶和吡啶的比率在实验误差内是相同的，但是吖啶和吖啶醛的水合比它们的吡啶类似物少20倍。与苯甲醛的比较表明，在它们的反应性，这两个杂…
Hydration rate constants and equilibrium constants have been obtained for 9-acridinecarboxaldehyde in aqueous solution. Under acidic conditions where the acridine is protonated, signals for the hydrate and free aldehyde forms can be observed as separate species in the 1H NMR spectrum. Integration provides the hydration equilibrium constant Using an apparent acidity constant obtained from a spectroscopic titration curve, the rate–pH profile was fitted to provide the hydration constant for the equilibration of the neutral acridines, KH = 0.07. This analysis also provides the acidity constants for the two acridinium ions, the aldehyde with pK = 3.78 and the hydrate with pK = 5.36. A comparison with the 4-pyridinecarboxaldehdye system reveals that the ratios for the acridine and pyridine are the same within experimental error, but that the acridine and acridinium aldehydes are 20-fold less hydrated than their pyridine analogs. A comparison with benzaldehydes reveals that, in their reactivities, the two hetero...