Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
J Sep Sci. 2010 Apr;33(8):1167-73. doi: 10.1002/jssc.200900797.
Partition coefficients for 84 varied compounds were determined for n-heptane-formamide biphasic partition system and used to derive a model for the distribution of neutral compounds between the n-heptane-rich and formamide-rich layers. The partition coefficients, log K(p), were correlated through the solvation parameter model giving log K(p)=0.083+0.559E-2.244S-3.250A-1.614B+2.387V with a multiple correlation coefficient of 0.996, standard error of the estimate 0.139, and Fisher statistic 1791. In the model, the solute descriptors are excess molar refraction, E, dipolarity/polarizability, S, overall hydrogen-bond acidity, A, overall hydrogen-bond basicity, B, and McGowan's characteristic volume, V. The model is expected to be able to estimate further values of the partition coefficient to about 0.13 log units for the same descriptor space covered by the calibration compounds (E=-0.26-2.29, S=0-1.93, A=0-1.25, B=0.02-1.58, and V=0.78-2.50). The n-heptane-formamide partition system is shown to have different selectivity to other totally organic biphasic systems and to be suitable for estimating descriptor values for compounds of low water solubility and/or stability.
为正庚烷-甲酰胺两相分配体系测定了 84 种不同化合物的分配系数，并用这些系数推导了一个描述非极性化合物在正庚烷相和甲酰胺相之间分配的模型。通过溶剂化参数模型对分配系数 log K(p) 进行关联，得到 log K(p)=0.083+0.559E-2.244S-3.250A-1.614B+2.387V，相关系数为 0.996，估计标准误差为 0.139，Fisher 统计量为 1791。在模型中，溶质描述符为过量摩尔折射度 E、偶极矩/极化率 S、整体氢键酸度 A、整体氢键碱度 B 和 McGowan 特征体积 V。该模型有望能够估算相同描述符空间内的进一步分配系数值，约为 0.13 个对数单位（E=-0.26-2.29，S=0-1.93，A=0-1.25，B=0.02-1.58，V=0.78-2.50）。正庚烷-甲酰胺分配体系对其他全有机两相体系具有不同的选择性，适合于估算低水溶性和/或低稳定性化合物的描述符值。
