Ahmed Hamid, Poole Colin F
Department of Chemistry, Wayne State University, Rm. 183, Detroit, MI 48202, USA.
J Chromatogr A. 2006 Feb 3;1104(1-2):82-90. doi: 10.1016/j.chroma.2005.11.065. Epub 2005 Dec 6.
Partition coefficients for 69 varied compounds were determined for the n-hexane-acetonitrile partition system and combined with 74 partition coefficients for (largely) terpenes, esters and alkylaromatic compounds determined by Isidorov and coworkers and 27 extraction p-values determined by Bowman and Beroza to derive a general model for the distribution of neutral compounds in the biphasic system. The partition coefficients, logK(p), were correlated through the solvation parameter model giving logK(p) = 0.097(+/- 0.049) + 0.189(+/-0.041)E - 1.332(+/-0.056)S - 1.649(+/-0.055)A - 0.966(+/-0.074)B + 0.773(+/-0.040)V with a multiple correlation coefficient of 0.985, standard error of the estimate 0.114, and Fischer statistic 1087. The solute descriptor E is the excess molar refraction, S is the dipolarity/polarizability, A and B are the overall hydrogen-bond acidity and basicity, respectively, and V is McGowan's characteristic volume. The model is expected to be able to estimate further values of the partition coefficient to about 0.1 log units and is applicable to a wide range of compounds except for n-alkylcarboxylic acids, which have higher partition coefficients than predicted, most likely due to the formation of oligomers (e.g. dimers) in the n-hexane layer.
测定了69种不同化合物在正己烷 - 乙腈分配体系中的分配系数，并将其与伊西多罗夫及其同事测定的74种（主要是）萜类、酯类和烷基芳烃化合物的分配系数以及鲍曼和贝罗扎测定的27个萃取p值相结合，以推导双相体系中中性化合物分布的通用模型。分配系数logK(p) 通过溶剂化参数模型进行关联，得到logK(p) = 0.097(±0.049) + 0.189(±0.041)E - 1.332(±0.056)S - 1.649(±0.055)A - 0.966(±0.074)B + 0.773(±0.040)V，复相关系数为0.985，估计标准误差为0.114，费舍尔统计量为1087。溶质描述符E是过量摩尔折射，S是偶极矩/极化率，A和B分别是总的氢键酸度和碱度，V是麦高恩特征体积。该模型预计能够将分配系数的进一步值估计到约0.1对数单位，并且适用于广泛的化合物，但正烷基羧酸除外，其分配系数高于预测值，最可能是由于在正己烷层中形成了低聚物（例如二聚体）。
