氯化铬和氯化镍浓度及其存在形式对ChCl-EG低共熔溶剂电导率的影响

Effects of existence form and concentrations of NiCl2·6H2O and CrCl3·6H2O on conductivity of ChCl-EG deep eutectic solvent

研究了氯化铬(CrCl3·6H2O)和氯化镍(NiCl2·6H2O)浓度和存在形式对氯化胆碱-乙二醇(ChCl-EG)低共熔溶剂的黏度和电导率的影响。电喷雾质谱(ESI-MS)分析结果表明,在溶解有CrCl3·6H2O和NiCl2·6H2O的ChCl-EG(ChCl-EG-NiCl2·6H2O-CrCl3·6H2O)溶液中出现了配阴离子[Cr(H2O)2Cl4]和[Ni(H2O)2Cl4]^2-。由此可以推断,Cr^3+(或Ni^2+)的两个d轨道、4s和4p轨道发生d2sp3杂化,形成6个等同的杂化轨道,接受6个配体(Cl^-和H2O)形成阴离子配合物。该溶液的电导率随温度的升高而增大,随总金属离子浓度的增大而减小。此外,溶液黏度随温度和总金属离子浓度的变化趋势与电导率相反。这主要是由于镍和铬配离子的形成改变了溶液中的离子组成。

The effects of existence form and total concentration of chromium chloride (CrCl3·6H2O) and nickel chloride (NiCl2·6H2O) on the conductivity and viscosity of choline chloride (ChCl)- ethylene glycol (EG) deep eutectic solvent were investigated. The ESI-MS analysis indicated that six-coordinated complexes are presented in the form of [Cr(H2O)2Cl4]^-. and [Ni(H2O)2Cl4]^2-. It is deduced that the complex anions are formed through d2sp3 hybrid orbitals of Cr^3+(or Ni^2+) ion and six d2sp3 hybrid orbitals are all filled with lone pair electrons which are donated by Cl. and O atoms of H2O, respectively. With the increase of temperature or decrease of total metal ions concentration, the electrical conductivity increases. In addition,the viscosity of the solution changes with temperature and total metal ion concentration as opposed to conductivity. This is mainly due to the formation of ions in the solution due to the formation of nickel and chromium complexions.