The choice of organic solvent is known to impact metal ion partitioning in solvent extraction systems, although an understanding based on molecular interactions has been largely qualitative. To provide a more quantitative and molecular scale understanding of extractant and solvent association in liquid-liquid solvent extraction systems, molecular dynamics studies of binary extractant/solvent systems are conducted for several organophosphorus solvating extractants across a range of organic solvents. Classical molecular dynamics potentials for the extractants are optimized in pure phase simulations. These potentials are then validated with binary extractant/solvent solutions by comparison to experimental data for percent volume change on mixing and mixing enthalpies. Trends in association free energy, mixing enthalpy and deviations from ideal mixing volume are reported for each extractant and solvent binary mixture. Contributions to those properties depending on extractant and solvent molecular structure are investigated, including the relative enthalpic favorability of extractant solutions in toluene, diethyl ether or n-hexane. Inclusion of the ether group in diethyl ether lowered the enthalpy of mixing to a similar degree as reducing the alkane solvent chain length from n-dodecane to n-hexane owing to dipole-dipole interactions with the “head” and “tail” regions of the extractant molecules, which depend on extractant alkyl chain length. Despite similar percent volume changes on mixing with n-hexane or diethyl ether, extractant/toluene mixtures were significantly more enthalpically favorable with an enthalpy of mixing minimum controlled by stoichiometry rather than volume fraction, as observed for alkane solvents.

尽管基于分子相互作用的理解在很大程度上是定性的，但已知有机溶剂的选择会影响溶剂萃取系统中金属离子的分配。为了提供对液-液溶剂萃取系统中萃取剂和溶剂缔合的更定量和分子规模的了解，对跨多种有机溶剂的几种有机磷溶剂化萃取剂进行了二元萃取剂/溶剂系统的分子动力学研究。在纯相模拟中优化了萃取剂的经典分子动力学潜能。然后，通过与混合和混合焓下体积变化百分比的实验数据进行比较，用二元萃取剂/溶剂溶液验证了这些电势。协会自由能的趋势，报告每种萃取剂和溶剂二元混合物的混合焓和与理想混合量的偏差。研究了取决于萃取剂和溶剂分子结构对这些性质的贡献，包括萃取剂溶液在甲苯，二乙醚或四氢呋喃中的相对焓有利性。ñ -己烷。在乙醚中的醚基的夹杂物降低混合以类似的程度作为减少从烷烃溶剂链长度的焓Ñ -dodecane到Ñ己烷由于偶极-偶极相互作用与“头”和的“尾”区萃取剂分子，这取决于萃取剂烷基链的长度。尽管在与混合类似百分比体积变化ñ -己烷或二乙醚，萃取剂/甲苯的混合物是更显著有利焓与混合最小通过化学计量，而不是体积分数控制的焓，作为用于烷烃溶剂观察到。