Abstract

An increase in the steric accessibility of a quaternary ammonium salt (QAS) exchange center leads to a significant increase in the exchange constant for most of the studied doubly charged anions (sulfate, sulfite, molybdate, tungstate, hydrogen phosphate, and selenate), which reaches for “pure” anion-exchange systems of more than five orders of magnitude. The effect of minimizing of an anion-exchange affinity was detected when a solvating additive, heptyl p-trifluoroacetylbenzoate, was introduced into the organic phase. The effect of steric accessibility is not entirely lost due to the conservation of charge of the solvate. The introduction of a solvating additive improves the affinity of anions for the QAS phase significantly (up to 6.5 orders of magnitude). The effect of anion size on the effect of steric accessibility of the exchange center was found for sulfate, sulfite, and thiosulfate ions. An inverse relationship was found for the tetrathionate ion; that is, with a decrease in steric accessibility of the QAS exchange center, anion-exchange extraction is weakened due to the large size of the \({{{\text{S}}}_{{\text{4}}}}{\text{O}}_{6}^{{2-}}\) ion.

中文翻译：

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交换中心具有不同的立体可达性的高级季铵盐对双电荷阴离子的阴离子交换萃取

摘要

季铵盐（QAS）交换中心的空间可及性增加导致大多数研究的双电荷阴离子（硫酸根，亚硫酸根，钼酸根，钨酸根，磷酸氢根和硒酸根）的交换常数显着增加。适用于五个以上数量级的“纯”阴离子交换系统。当使用溶剂化添加剂庚基p时，可检测到最小化阴离子交换亲和力的作用。将-三氟乙酰基苯甲酸酯引入有机相。由于溶剂化物电荷的保留，空间可及性的影响没有完全丧失。引入溶剂化添加剂可显着提高阴离子对QAS相的亲和力（最高6.5个数量级）。对于硫酸根，亚硫酸根和硫代硫酸根离子，发现阴离子大小对交换中心空间可及性的影响。发现四硫氰酸根离子成反比关系。也就是说，随着QAS交换中心的空间可及性下降，由于\（{{{\ text {S}}} _ {{\ text {4}} } {\ text {O}} _ {6} ^ {{2-}} \）离子。