Direct Photometric Measurement of Interfacial Reaction in Solvent Extraction Systems

采用高速搅拌法和直接光度法对溶剂萃取体系中的界面反应进行了研究。在本研究中阐明了以下几点：1。2′-羟基-5′-壬基二苯甲酮肟萃取CU （II）和NI （II）的控速步骤是萃取剂阴离子与界面金属离子形成1:1配合物。讨论了庚烷和氯仿的溶剂效应。采用光电二极管阵列检测器测定了双硫腙和1,10 -菲罗啉（phen）对NI （II）的协同萃取率。在苯乙酯浓度高于双硫腙浓度的条件下，在界面处形成中间络合物。对后三种体系进行了界面光谱的直接测量；(1)测定了β -二酮在阴离子、阳离子和非离子o/w微乳中的解离常数。解离常数的介质效应用表面电荷对β -二酮酸酯吸附的静电效应来解释。(2)制作了用于搅拌分散体系吸收光谱测量的光学电池，研究了四苯基卟啉（TPP）在甲苯/硫酸体系中的界面质子化作用。实验结果表明，双质子化的TPP在界面处形成了聚合体。(3)采用聚四氟乙烯过滤器或聚四氟乙烯片材作为支撑材料，观察液膜的界面光谱。用该方法测定了TPP和罗丹明B衍生物的界面质子化。该方法现已应用于界面动力学和电场对界面反应的影响的测量。

The interfacial reaction in solvent extraction systems was investigated by means of the high-speed stirring method and direct photometric measurement of the interface. The followings were elucidated in the present study ;1. The rate-controlling step of the extraction of CU (II) and NI (II) with 2'-hydroxy-5'-nonylbenzophenone oxime was the formation of 1 : 1 complex between the anion of the extractant and the metal ions which occurred at interface. The solvent effect of heptane and chloroform was also discussed.2. The synergistic extraction rate of NI (II) with dithizone and 1, 10-phenanthroline (phen) was measured by using a photodiode-array detector. Under the conditions of higher concentration for phen than that for dithizone, an intermediate complex was formed at the interface.3. The direct measurements of interfacial spectra were made for the next three systems ;(1) The dissociation constants of beta-diketones were determined in anionic, cationic and nonionic o/w microemulsions. The medium effect for the dissociation constants was explained in terms of the electrostatic effect of the surface charge on the adsorption of beta-diketonates.(2) The optical cell for the measurement of absorption spectra of the dispersed systems by stirring was made and the interfacial protonation of tetraphenylporphine (TPP) at toluene/ sulfuric acid system was investigated. Experimental results showed the formation of diprotonated TPP and its aggregate at the interface.(3) Interfacial spectra of liquid membrane was observed by using Teflon filter or Teflon sheet as the supporting material. The interfacial protonations of TPP and a Rhodamine B derivative were measured by this method. This approach is now applied for the measurements of an interfacial kinetics and an electric field effect on interfacial reaction.