2-乙基已基膦酸单2-乙基已基酯(P_(507))在水—癸醇体系中两相电离常数的测定

Determination of Dissociation Constant of Mono-2-ethylhexyl 2-ethylhexyl Phosphonate in Water-Decanol System by the Two-phases Titration

本文用VPO 法证实P_(507)在癸醇中以单体形式存在的基础上,用电导滴定法测定了水相中萃取剂总浓度S,并用pH 两相滴定法测定了P_(507)在水一癸醇体系中的电离常数K_α、两相分配常数Kd 和两相电离常数K_(αE).测定值:S=5.30×10^(-5)M; pKα=3.88;1gKd=3.18; pK_(αE)=7.06.

It was fortified that mono-2-ethylhexyl 2-ethylhexyl phosphonate,HEH(EHP),is monomeric in decanol by vapour pressure osmometry(VPO)method.Thetotal concentration of HEH(EHP)in the aqueous solution was determined bythe conductometric titration.The dissociation constant of HEH(EHP)in thewater-decanol system,the distribution constant and dissociation constant ofHEH(EHP)between the two phases were determined by two-phases titration.