Structure Of Phosphine-Functionailzed Ionic Liquids And Investigation On Their Properties

Chemistry of ionic liquids?ILs?has advanced greatly in the past decades.Researches from academia and industry have covered wide areas,which explore from the fundamental nature of such nontraditional materials to various potential applications.ILs have good structural tenability and can exhibite interesting physicochemical properties by altering the compositions of cations and anions.In this paper,a series of phosphine-functionailzed ionic liquids were designed and synthesized by introducing P=O functional groups.It consists of three parts:?1?Synthesis of a series of organic phosphine functional ionic liquids with different cation structures of quaternary phosphonium salts,imidazole-based?monodentate cationic monofunctional asymmetry,bidentate cationic bifunctional symmetry,bidentate cationic monofunctional asymmetry and bidentate dicationic bifunctional symmetry?,and was characterized by FT-IR,NMR and HRMS.?2?Viscosities and conductivities of three binary mixtures of 4-?diethoxyphosphoryl?butyl triphenylphosphonium hexafluorophosphate?PFIL?with organic solvents were measured at temperature range from 293.15 to 343.15 K in the mole fraction of IL from 0.01 to 0.14.By linear fitting the relationship between temperature and viscosity,it is found that the relationship between viscosity and temperature can be accurately described by the VFT equation.The relationship between conductivity and temperature is consistent with both the Arrhenius equation and the VFT equation,and the relationship of the conductivity with the mole fraction of PFIL is greatly agreed with the Casteel�Amis empirical equation.In addition,the conductivity activation energy is also estimated.?3?The application of various phosphine-functionailzed ionic liquids in the extraction for Nd?III?was studied with EtOAc as diluent.The effects of pH,time,temperature,salting-out agents and concentration on the extraction efficiency of Nd?III?were investigated.Compared with the different cationic structures and whether adding a salting-out agent to Nd?III?in aqueous phase,it was found that the addition of salting-out agent can promote the extraction of rare earth Nd?III?by ILs.Meanwhile,it is indicated by logD-log[IL]slope method,when LiNTf₂ is added,the neutralization mechanism of the extractor is transformed into an ion association mechanism.When the anion is NTf₂^-,the extraction capacity of the Nd?III?solution of 0.005 M LiNTf₂ extracted by organic phosphine functional ionic liquids with different cationic structure is:IL-8>IL-3>IL-2?IL-5>IL-4.Under the same extraction conditions,the relationship between functionalized ionic liquid structure and extraction capacity is as follows:bidentate dicationic bifunctional symmetry ionic liquids>bidentate cationic bifunctional symmetry ionic liquids>monodentate cationic monofunctional asymmetry ionic liquids?bidentate cationic monofunctional asymmetry ionic liquids.