二(2-乙基己基)磷酸萃取氨基苯甲酸的相平衡分配系数

络合萃取法分离极性有机物稀溶液具有高效性和高选择性，本文以二（２－乙基已基）磷酸（Ｄ２ＥＨＰＡ）为络合剂；正辛烷或正辛醇为稀释剂，在不同的ＰＨ值条件下实验测定了氨基苯甲酸稀溶液的萃取相分配系数，讨论了影响因素，分析了萃合物的组成。提出了平衡分配系数的关系式。

The Extraction Equilibrium Distribution Ratio of Aminobenzoic Acid with Di(2-ethylhexyl)phosphoric Acid

The separation technique of extraction based on reversible chemical complexation can be of high capacity and high selectivity for separating polar organic solutes from dilute solution. Aminobenzoic acid is a valuable chemical product. The downstream processing technology for the extraction and recovery of aminobenzoic acid presents a challenging separation problem. Aminobenzoic acid has two kinds of functional groups (-COOH and -NH2), so it is very difficult to be biodegradated. The extraction medthed for treating the waste water with aminobenzoic acid needs to be developed. The p-aminobenzoic and oaminobenzoic acid were selected to be separated from dilute solution. By using Di-(2-ethylhexyl)phosphoric acid (D2EHPA) as complexing agent, 1-octanol and n-octane as diluents, a series of extraction equilibrium experiments were carried out. The effects of complexing agent concentration, diluents and pH value of aqueous solution on distribution ratio D were discussed. The infrared spectrogram of loaded organic phase illustrated that pH condition had little effect on the structure of complex. There are ion association and canon exchange reactions in the extraction. One aminobenzoic acid is extracted by forming a complex with four monomeric D2EHAPs for n-octane as diluent, whereas with two or four monomeric D2EHPAs for 1-octanol as diluent. An expression of equilibrium distribution ratio has been proposed.