三烷基氧膦络合萃取一元有机羧酸

Liquid-Liquid Extraction of Carboxylic Acid with Trialkyl Phosphine Oxide

络合萃取法对极性有机物稀溶液的分离具有高效性和高选择性。选择甲酸、乙酸、丙酸、丁酸为分离对象 ,三烷基氧膦 (TRPO)为络合剂 ,煤油为稀释剂 ,进行了系统的萃取相平衡实验 ,测定了络合剂浓度、稀释剂组成等因素对萃取平衡分配系数的影响。实验结果表明 ,溶质的亲油性对络合萃取平衡影响起主导作用 ;随TRPO浓度增大 ,萃取平衡分配系数呈增大趋势 ;随溶质初始浓度增大 ,有机相的溶质浓度向饱和萃取量接近 ;饱和萃取量随络合剂浓度的增大而增大。对相平衡分配系数进行拟合 ,精度令人满意。

Extraction of carboxylic acids from dilute solutions based on reversible chemical complexation was a highly effective and selective separation technique. Studies were made for the extraction of formic, acetic, propionic and butyric acids by TRPO, a trialkyl phosphine oxide, dissolved in kerosene, and the extraction-saturated curves were obtained by measuring the extraction capacities under different compound conditions of concentration of complexing agent and content of modifier. The extraction capacities increased with the increase in the concentration of complexing agent. The acid concentration in organic phase increased and approached the saturating extraction value with the increase of the acid concentration in aqueous phase. The saturated concentration of acid in organic phase increased with the increase of the concentration of complexing agent and would reach the same concentration as complexing agent in the end. Extraction equilibrium constant K_(11)was then obtained by correlating experimental data using least square method. The calculated values were in good agreement with the experimental ones.