三辛胺萃取有机羧酸的机理(Ⅱ)──有机羧酸的pK_a值和亲油性的影响

MECHANISM OF EXTRACTION FOR CARBOXYLIC ACID WITH TRI-N-OCTYLAMINE(Ⅱ)──EFFECTS OF pK_a AND HYDROPHOBICITY

在本文（Ⅰ）报研究的基础上，进一步考察了三辛胺──有机羧酸体系的红外光谱图．选用的有机羧酸为甲酸、丁酸、己酸和氯乙酸等．通过红外光谱分析定量求取了负载羧酸有机相的I值，讨论了有机羧酸的pK_a值和亲油性对不同形态萃合物组成比的影响．

In this work,the organic phase samples loaded with carboxylic acid were studied by FT-IR spectroscopy.Thi-n-octylamine(TOA)was used as a complexing agent.The carboxylic acids used are formic acid,butyric acid,hexanoic acid and chloroacetic acid.The fraction of ion──pair extent and hydrogen──bonded extent in the systems were determined quantitatively.The effects of pK_a and hydrophobicity of carboxylic acids on the fraction were determined.The lower the pK_a of carboxylic acid and the higher its hydrophbicity,the higher the fraction of ion-pair extent would be.