Equations for the Transfer of Neutral Molecules and Ionic Species from Water to Organic phases
Equations for the Transfer of Neutral Molecules and Ionic Species from Water to Organic phases
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DOI：
10.1021/jo902388n
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发表时间：
2010-02-19
影响因子：
3.6
通讯作者：
Acree, William E., Jr.
中科院分区：
文献类型：
--
作者：
Abraham, Michael H.;Acree, William E., Jr.
可用于中性分子和离子的分配系数的方程已被修订，并且特定于离子的术语已被重新评估。本文根据羧酸的pK（a）随溶剂的变化，提出了一种测定羧酸根阴离子在水-有机溶剂中分配系数的新方法。使用这些分配系数，羧酸根阴离子的描述符，中性分子的描述符相同的规模，已获得71个这样的阴离子。对于13个羧酸根阴离子的测试集，描述符可以预测，进而导致预测的78个日志P值超过6个水溶剂系统的绝对误差为0.13和标准偏差只有0.55个对数单位。描述符已获得26质子化胺作为训练集和描述符预测17质子化胺作为测试集。预测的描述符，进而导致预测的18个日志P值的质子化胺的绝对误差为0.09和0.39个对数单位的标准偏差。羧酸根阴离子是最强的单官能氢键碱，质子化胺是我们所研究的最强的单官能氢键酸。
Equations that can be used for partition coefficients of both neutral molecules and ions have been revised, and the term that is specific to ions has been re-evaluated. A new method has been devised for the determination of partition coefficients from water to organic solvents for carboxylate anions that is based on the variation of pK(a) for carboxylic acids with solvent. Using these partition coefficients, descriptors for carboxylate anions, on the same scale as descriptors for neutral molecules, have been obtained for 71 such anions. For 13 carboxylate anions in a test set, descriptors could be predicted that in turn led to predictions of 78 log P values over six water-solvent systems with an absolute error of 0.13 and a standard deviation of only 0.55 log units. Descriptors have been obtained for 26 protonated amines as a training set and descriptors predicted for 17 protonated amines as a test set. The predicted descriptors in turn led to the prediction of 18 log P values for protonated amines with an absolute error of 0.09 and a standard deviation of 0.39 log units. The carboxylate anions are the strongest monofunctional hydrogen bond bases, and the protonated amines are the strongest monofunctional hydrogen bond acids that we have studied.