Direct Photometric Measurement of Interfacial Reaction in Solvent Extraction Systems

点击翻译按钮获取中文摘要

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.