Separation of carboxylic acids from dilute aqueous solutions is a challenging problem, and reactive extraction has been examined as an attractive alternative for this process. This study aims to investigate the reactive extraction of pimelic acid (PA) using tri-n-octylamine (TOA) in 1-hexanol, 1-octanol, xylene, and n-hexane. The highest extraction efficiency (E (%)) and distribution coefficient (K_D) were obtained at pH 3, which is the unadjusted pH of the aqueous PA solution. Extractive efficiency varied inversely with temperature and initial PA concentration but increased with the increase in TOA amount. The highest E (%) and K_D values (98.5% and 67.2, respectively) were obtained with 1-hexanol at initial TOA and PA concentrations of 0.2700 and 0.0375 mol/kg, respectively. The process was modeled using multilinear regression, and the model closely correlated with experimental results for all organic solvents tested.

中文翻译：

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反应萃取法在各种有机溶剂中使用三正辛胺分离庚二酸：平衡和建模

从稀水溶液中分离羧酸是一个具有挑战性的问题，并且反应萃取已被研究为该过程的有吸引力的替代方案。本研究旨在研究在 1-己醇、1-辛醇、二甲苯和正己烷中使用三正辛胺 (TOA) 反应萃取庚二酸 (PA) 。最高的萃取效率 ( E (%)) 和分配系数 ( K _D ) 在 pH 值 3 时获得，这是未调整的 PA 水溶液的 pH 值。提取效率与温度和初始 PA 浓度成反比，但随着 TOA 量的增加而增加。最高E (%) 和K _D在初始 TOA 和 PA 浓度分别为 0.2700 和 0.0375 mol/kg 时，使用 1-己醇获得值（分别为 98.5% 和 67.2）。该过程使用多元线性回归建模，该模型与所有测试的有机溶剂的实验结果密切相关。