Preparation Of Novel Ionic Liquids And Electrodeposition Of Metals

Ionic liquids have excellent properties such as low volatility,high thermochemical stability and high ionic conductivity.In recent years,the synthesis and preparation of new ionic liquid as an aprotic reaction solvent,its application in organic and catalytic synthesis,separation analysis,electrochemical and other fields has been a hot topic of research.In this study,based on the synthesis of 1-butyl-3-methylimidazolium acetate（[C₄C₁Im][OAc]）,two new ionic liquids were synthesized:Matte type ionic liquid double（trifluoromethyl）sulfonimide dimethyl sulfide[S_2,1,1][Tf₂N],double（trifluoromethyl）sulfonimide diethyl methyl sulfide[S_2,2,1][Tf₂N],double（trifluoromethyl）sulfonimide butyldimethyl sulfide[S_4,1,1][Tf₂N];A novel nitrogen-containing ionic liquid bis（trifluoromethylsulfonyl）imide triethylammonium methyl[N_2,2,2,1][Tf₂N].The physical and chemical structure properties of ionic liquids were studied.The electrochemical behavior and electrocrystallization process of copper in ionic liquid were studied by electrodeposition of copper coating by potentiostatic method using ionic liquid as solvent and copper sulfate as copper salt.The effects of liquid concentration and coating substrate on coating morphology,crystal structure and other properties were investigated,and the main conclusions were as follows:（1）The ionic liquid[C₄C₁Im][OAc],[S_2,1,1][Tf₂N],[S_2,2,1][Tf₂N],[S_4,1,1][Tf₂N],[N_2,2,2,1][Tf₂N]was synthesized by the two-step method,and the performance of the ionic liquid was tested.The composition of the synthesized ionic liquid was determined by infrared spectroscopy,thermogravimetric analysis,X-ray photoelectron spectroscopy and hydrogen nuclear magnetic resonance spectroscopy.（2）the Cu²⁺in[C₄C₁Im][OAc],[S_2,1,1][Tf₂N],[S_2,2,1],[Tf₂N],[S_4,1,1][Tf₂N],[N_2,2,2,1][Tf₂N]nucleation process of ionic liquid as the three-dimensional instanta neous nucleation,The kinetic processes in ionic liquids are all irreversible proces ses controlled by diffusion and mass transfer.The diffusion coefficient of Cu SO₄-[S_2,1,1][Tf₂N]ionic liquid is the largest,and the diffusion coefficient of Cu²⁺redu ction to Cu⁺and Cu⁺reduction to Cu⁰are 0.004994 and 0.005452cm²/s,respecti vely.The ion transport capacity is the strongest.（3）The[S_2,1,1][Tf₂N]ionic liquid copper coating of 0.3mol/LCu SO₄has the best electrodeposition performance of the matrix alloy steel,its cathodic current efficiency is74.74%,the coating thickness is 20.08um,and the EDS test of the coating shows that the Cu content is 59%.In addition to the lack of fine and tight surface,the alloy steel matrix plating is superior to the zinc matrix in other aspects.For[S_2,1,1][Tf₂N],[C₄C₁Im][OAc]ionic liquid systems,the higher the copper ion concentration,the tighter the coating,but in the[N_2,2,2,1][Tf₂N]ionic liquid,when the Cu²⁺concentration reaches or exceeds 0.1mol/L,the ionic liquid concentration can no longer affect the compactness of the sedimentary layer.（4）The influence of the length of side chain substituents and temperature on the electrodeposition process of Cu²⁺is studied.The results show that the longer side chain substituents are,the more activation energy is required for Cu²⁺reduction,and the shorter side chain substituents are,the less activation energy is required.The higher the temperature,the Cu²⁺in ionic liquid is more likely to be reduced to elemental,but also more easily oxidized.（5）[S_2,1,1][TF₂N]ionic liquid electrodeposition effect is good,its kinematic viscosity is 13.64mm²/s at room temperature,adding an appropriate amount of DMSO solvent will reduce the kinematic viscosity,significantly improve ion transport capacity,and have a positive effect on electrodeposition effect.The temperature has a linear relationship with the viscosity of[S_2,1,1][Tf₂N]ionic liquid,and appropriately increasing the temperature is beneficial to the electrodeposition of ionic liquids in the system.At the same time,with the increase of deposition time,the higher the content of Cu²⁺.