Distribution thermodynamics of 1,10-phenanthroline in non-ionic surfactant Triton X-100 micelles
Distribution thermodynamics of 1,10-phenanthroline in non-ionic surfactant Triton X-100 micelles
复制标题
1,10-菲咯啉在非离子表面活性剂Triton X-100胶束中的分布热力学
DOI：
10.1039/b009132o
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
S. Ishiguro
中科院分区：
文献类型：
--
作者：
R. Kanzaki;Y. Umebayashi;K. Uemura;S. Ishiguro
采用电位法和滴定量热法研究了非离子表面活性剂Triton X-100胶束中1,10-菲咯啉（phen）和2,9-二甲基-1,10-菲咯啉（dmphen）的分布热力学
在 298 K 下。这两种配体在酸性溶液中形成 HL+ 和 HL2+（L = phen 和 dmphen）。在含有不同浓度的 Triton X-100 的水溶液中测定了它们的形成常数，并发现它们的形成常数随着表面活性剂浓度的增加而降低。通过考虑表面活性剂溶液作为非均质溶剂混合物，可以用胶束中中性菲咯啉的容纳来解释这种减少。还研究了将表面活性剂作为第三反应物处理的情况，
并获得了表面活性剂与菲咯啉之间相互作用的热力学参数，即菲咯啉从水溶液转移到胶束假相的吉布斯能量、焓和熵。中性配体 L 的吉布斯转移能为 − 8.2 和 − 11.7 kJ mol−1
分别为 L = phen 和 dmphen。相应的转移焓既小又为负，这意味着这些中性 1,10-菲咯啉仍然通过亲水性氮位点在胶束和水中强烈水合。
The distribution thermodynamics of 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (dmphen) in micelles of the non-ionic surfactant Triton X-100 were studied by potentiometry and titration calorimetry
at 298 K. Both of these ligands form HL+ and HL2+ (L = phen and dmphen) in acidic solution. Their formation constants were determined in aqueous solutions containing various concentrations of Triton X-100, and were found to decrease with increasing concentration of the surfactant. The decrease is explained in terms of accommodation of neutral phenanthrolines in micelles by taking into account the surfactant solution as a heterogeneous solvent mixture. The case in which the surfactant is treated as the third reactant was also examined,
and thermodynamic parameters for the interaction between the surfactant and phenanthrolines, i.e. the Gibb's energies, enthalpies and entropies of transfer of phenanthrolines from aqueous solution to a micellar pseudo-phase, were obtained. The Gibb's energies of transfer of the neutral ligand L are − 8.2 and − 11.7 kJ mol−1
for L = phen and dmphen, respectively. The corresponding enthalpies of transfer are both small and negative, implying that these neutral 1,10-phenanthrolines are still strongly hydrated in micelles, as well as in water, through the hydrophilic nitrogen sites.