Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
J Chromatogr A. 2011 Jul 15;1218(28):4525-36. doi: 10.1016/j.chroma.2011.05.023. Epub 2011 May 14.
Partition coefficients for varied compounds were determined for the organic solvent-dimethyl sulfoxide biphasic partition system where the organic solvent is n-heptane or isopentyl ether. These partition coefficient databases are analyzed using the solvation parameter model facilitating a quantitative comparison of the dimethyl sulfoxide-based partition systems with other totally organic partition systems. Dimethyl sulfoxide is a moderately cohesive solvent, reasonably dipolar/polarizable and strongly hydrogen-bond basic. Although generally considered to be non-hydrogen-bond acidic, analysis of the partition coefficient database strongly supports reclassification as a weak hydrogen-bond acid in agreement with recent literature. The system constants for the n-heptane-dimethyl sulfoxide biphasic system provide an explanation of the mechanism for the selective isolation of polycyclic aromatic compounds from mixtures containing low-polarity hydrocarbons based on the capability of the polar interactions (dipolarity/polarizability and hydrogen-bonding) to overcome the opposing cohesive forces in dimethyl sulfoxide that are absent for the interactions with hydrocarbons of low polarity. In addition, dimethyl sulfoxide-organic solvent systems afford a complementary approach to other totally organic biphasic partition systems for descriptor measurements of compounds virtually insoluble in water.
不同化合物的分配系数已在有机溶剂-二甲基亚砜两相分配体系中确定，其中有机溶剂为正庚烷或异戊醚。使用溶剂化参数模型对这些分配系数数据库进行了分析，从而可以对基于二甲基亚砜的分配系统与其他全有机分配系统进行定量比较。二甲基亚砜是一种中等内聚性溶剂，具有合理的偶极/极化性和强氢键碱性。尽管通常认为它不是氢键酸性物质，但对分配系数数据库的分析强烈支持将其重新分类为弱氢键酸，这与最近的文献一致。正庚烷-二甲基亚砜两相体系的系统常数解释了从含有低极性烃的混合物中选择性分离多环芳烃化合物的机制，这是基于极性相互作用（偶极/极化性和氢键）克服二甲基亚砜中内聚相互作用的能力，而这些相互作用在与低极性烃的相互作用中不存在。此外，二甲基亚砜-有机溶剂体系为其他全有机两相分配系统提供了一种互补方法，可用于对水中几乎不溶的化合物进行描述符测量。
