一元有机酸在液液两相间的分配平衡

Distribution Equilibrium of Some Monocarboxylic Acids between Water and Organic Solvent

考察了甲酸、乙酸、丙酸、丁酸及氯乙酸、二氯乙酸和三氯乙酸在水与各种有机溶剂间的分配平衡．结果表明，有机酸在惰性溶剂中以二聚体存在，在非惰性溶剂中以氢键与溶剂缔合;惰性溶剂中溶剂的偶极项π和溶质的分子体积V3、非惰性溶剂中溶剂的碱性标度参数βH和溶质的酸性标度参数αH分别是影响分配性能的主要因素;在热力学上，分配过程均为墒增过程，除TBP体系放热外，其余过程均为吸热;另外，无机盐对分配过程也有影响，除使甲酸的分配略有减弱外，其余酸的分配性能均有所增强．

The distribution equilibrium of some monocarboxylic acids (methanoic, ethanoic,propanoic, butanoic, chloroethanoic, dichlorocthanoic and trichioroethanoic acid) between water and organic solvent was studied. The results show that the add behave as a monomerized solute in non-inert solvent and dimerized in inert solvent. The solvent polarity-poladrizability effect π and the solute molecular volume Vs in inert solvent, the solvent HBA basicity βH and the solute HBD addity aH in non-inert solvent are the main factors influencing the distribution equilibrium, respectively. The effect of temperature on the equilibrium was investigated and the enthalpy of the process was obtained, the process proceeds with a favolable entropy. The salt effect was also discussed.