Mehta S K, Chaudhary Savita, Kumar Rajeev, Bhasin K K
Department of Chemistry and Centre of Advanced Studies in Chemistry, Panjab University, Chandigarh 160014, India.
J Phys Chem B. 2009 May 21;113(20):7188-93. doi: 10.1021/jp811310f.
This study investigated the water solubility enhancements of organochalcogen compounds, viz. bis(diphenylmethyl)diselenide [(C6H5)2CHSe]2 and 3,3'-dibromo-4,4'-dimethyl-2-dipyridyl diselenide [C12H10N2Se2Br2] in micellar media. Two cationic and one nonionic surfactants possessing the same hydrocarbon tail, namely hexadecyltrimethylammonium bromide (C16Br), hexadecyltrimethylammonium chloride (C16Cl), and polyoxyethylene(20)mono-n-hexadecyl ether (Brij 58), in their single as well as equimolar binary and ternary mixed states have been used. Solubilization capacity has been evaluated in terms of the molar solubilization ratio and the micelle water partition coefficients. The association constants between the solubilizate molecules and that of micelle and the average number of solubilizate molecules per micelle have also been quantified. The results showed that cationic surfactants exhibit less solubilization as compared to nonionic surfactant. The mixing effects of surfactants on micelle formation and solubilization efficiencies have also been discussed. It has been observed that cationic-nonionic binary combinations showed better solubilization capacity as compared to pure cationic, nonionic, or cationic-cationic binary mixtures. An equimolar cationic-cationic-nonionic ternary surfactant system provides higher solubilization than cationic-cationic but lowers than their cationic-nonionic counterpart. In addition, Fourier transform infrared has been employed with fair success to predict the information regarding the aggregates and the mechanism of docking of the surfactant and the chalcogenides in the system. The analysis has provided valuable information for the selection of mixed surfactants for solubilizing water-insoluble compounds. Certainly the solubilization ability of these surfactants is not simply related to molar capacity. The results give sufficient encouragement to warrant more detailed investigation of the features of surfactant properties that affect solubilization.
本研究考察了有机硫属化合物，即双（二苯基甲基）二硒醚[（C6H5）2CHSe]2和3,3'-二溴-4,4'-二甲基-2-二吡啶基二硒醚[C12H10N2Se2Br2]在胶束介质中的水溶性增强情况。使用了三种具有相同烃链的表面活性剂，即十六烷基三甲基溴化铵（C16Br）、十六烷基三甲基氯化铵（C16Cl）和聚氧乙烯（20）单正十六烷基醚（Brij 58），它们处于单一、等摩尔二元和三元混合状态。根据摩尔增溶比和胶束-水分配系数评估了增溶能力。还对被增溶物分子与胶束之间的缔合常数以及每个胶束中被增溶物分子的平均数进行了量化。结果表明，与非离子表面活性剂相比，阳离子表面活性剂的增溶作用较小。还讨论了表面活性剂对胶束形成和增溶效率的混合效应。据观察，与纯阳离子、非离子或阳离子-阳离子二元混合物相比，阳离子-非离子二元组合表现出更好的增溶能力。等摩尔阳离子-阳离子-非离子三元表面活性剂体系的增溶能力高于阳离子-阳离子二元体系，但低于阳离子-非离子二元体系。此外，傅里叶变换红外光谱已成功用于预测有关聚集体以及表面活性剂和硫属化合物在体系中的对接机制的信息。该分析为选择用于增溶水不溶性化合物的混合表面活性剂提供了有价值的信息。当然，这些表面活性剂的增溶能力不仅仅与摩尔容量有关。这些结果给予了足够的鼓励，以保证对影响增溶作用的表面活性剂性质特征进行更详细的研究。
