SANS Study of HCl Extraction by Selected Neutral Organophosphorus Compounds in n-Octane
SANS Study of HCl Extraction by Selected Neutral Organophosphorus Compounds in n-Octane
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选定中性有机磷化合物在正辛烷中萃取 HCl 的 SANS 研究
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
M. Antonio
中科院分区：
文献类型：
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作者：
R. Chiarizia;D. Stepinski;M. Antonio
通过酸和水的液-液分布以及小角中子散射 (SANS) 测量，研究了磷酸三(2-乙基己基) (TEHP)、磷酸三正辛酯 (TOP) 和三正辛基氧化膦 (TOPO) 在正辛烷中萃取 HCl 的情况。在所用实验条件下，TEHP 和 TOP 未观察到重有机相（第三相）的形成，而对于 0.4 M TOPO，23°C 时 HCl 极限有机浓度 (LOC) 为 0.32 M（平衡水相中含有 5.1 M HCl）。对于水相中 HCl 浓度较高的情况，有机相分为轻层和重层。对于 TEHP 和 TOP，使用具有表面粘附力的硬球的 Baxter 模型解释的 SANS 结果表明，仅形成了具有很小胶束间吸引力的小反胶束。对于 TOPO，散射信号表明形成了更大且强相互作用的胶束。 TOPO 系统中 LOC 样品的粘性参数 τ−1 和相互作用势能 U(r) 的临界值与先前为磷酸三正丁酯 (TBP) 开发的第三相形成模型一致。根据该模型，有机相分裂是由于有机相中的萃取剂形成的反胶束的极性核之间的范德华相互作用所致。
The extraction of HCl by tri(2-ethylhexyl) phosphate (TEHP), tri-n-octyl phosphate (TOP), and tri-n-octylphosphine oxide (TOPO) in n-octane was investigated by liquid-liquid distribution of acid and water and small-angle neutron scattering (SANS) measurements. No formation of a heavy organic phase (third phase) was observed with TEHP and TOP under the experimental conditions used, whereas for 0.4 M TOPO the HCl limiting organic concentration (LOC) at 23°C was 0.32 M (with 5.1 M HCl in the equilibrium aqueous phase). For higher HCl concentrations in the aqueous phase, the organic phase splits into a light and a heavy layer. For TEHP and TOP, the SANS results, interpreted using the Baxter model for hard spheres with surface adhesion, indicated the formation of only small reverse micelles with little intermicellar attraction. For TOPO, the scattering signals suggested the formation of much larger and strongly interacting micelles. The critical values of the stickiness parameter, τ−1, and the interaction potential energy, U(r), for the LOC sample in the TOPO system were consistent with the model for third-phase formation previously developed for tri-n-butyl phosphate (TBP). According to this model, organic phase splitting is due to van der Waals interactions between the polar cores of reverse micelles formed by the extractants in the organic phase.