Equipe Thermodynamique, Equilibre de phases et Analyses Avancées ThEAA, Département Chimie et Sciences de la Vie, Faculté des Sciences, Université Saint Esprit de Kaslik, B.P. 446 Jounieh, Lebanon.
Chemosphere. 2011 Feb;82(6):929-34. doi: 10.1016/j.chemosphere.2010.10.029. Epub 2010 Nov 20.
In this paper, we present the effect of inorganic cations such as Na+, K+, Ca2+, Mg2+ on the salting-out phenomenon of metalaxyl from pure water to aqueous salt solutions. Moreover the 1-octanol/water partition coefficient in pure water is presented. To accomplish this, aqueous solubility of metalaxyl was determined in pure water, in different salt solution (NaCl, KCl, CaCl2 and MgCl2), and at different concentration level ranging from 0.01 to 1.5 M. The 1-octanol/water partition coefficient was determined using the static shake-flask method. Solubility was determined using dynamic saturation method for pure water in the range of 298.15-325.15 K and at 298.15 K for different salt solutions. The solubility value in pure water for studied interval was found constant (m=3.118×10(-2) mol kg(-1)). Solubility values were used to calculate the standard molar Gibbs free energy of dissolution (ΔsolG°) and transfer (ΔtrG°) at 298.15 K. The values of ΔtrG° from pure to all studied aqueous salt solutions did not exceed 2 kJ mol(-1), the value of ΔsolG° of dissolution is 18.5 ±0.72 kJ mol(-1). The 1-octanol/water partition coefficient in pure water log Ko/w is equal to 1.69. The obtained results confirm the classification of the neutral metalaxyl as a slightly hydrophobic molecule.
本文研究了无机阳离子（如 Na+、K+、Ca2+、Mg2+）对金属吖啶从纯水到盐溶液中的盐析现象的影响。此外，还介绍了金属吖啶在纯水中的 1-辛醇/水分配系数。为了实现这一目标，测定了金属吖啶在纯水中以及不同盐溶液（NaCl、KCl、CaCl2 和 MgCl2）中的溶解度，盐浓度范围从 0.01 到 1.5 M。1-辛醇/水分配系数采用静态摇瓶法测定。在 298.15-325.15 K 的范围内，采用动态饱和法测定了纯水中的溶解度，在 298.15 K 时测定了不同盐溶液中的溶解度。在所研究的温度范围内，纯水中的溶解度值保持不变（m=3.118×10(-2) mol kg(-1)）。利用溶解度值计算了 298.15 K 时的标准摩尔溶解吉布斯自由能（ΔsolG°）和转移吉布斯自由能（ΔtrG°）。从纯溶剂到所有研究的盐溶液的 ΔtrG°值均不超过 2 kJ mol(-1)，溶解的 ΔsolG°值为 18.5 ±0.72 kJ mol(-1)。金属吖啶在纯水中的 1-辛醇/水分配系数 log Ko/w 等于 1.69。所得结果证实，中性金属吖啶可归类为疏水性较弱的分子。
