水对室温熔盐[Bpy]BF_4结构与性质的影响

采用分子动力学模拟方法研究了298.15 K、0.1 MPa下摩尔分数为0.05~0.95的水对室温熔盐1-丁基吡啶四氟硼酸(Bpy]BF4)结构与性质的影响.获得了体系的径向分布函数、配位数和空间分布函数等微观结构及其密度、自扩散系数、电导率和粘度等物理化学性质.模拟密度与实验结果符合很好;体系中各组分间的径向分布函数和配位数均随水摩尔分数的增加有规律的变化;获得了各组分之间的三维空间分布情况;随水摩尔分数的增加,阴阳离子之间的相互作用被削弱,同时水与阴离子、阳离子及水分子之间的相互作用逐渐增强,水、阴离子和阳离子的自扩散系数增大,体系粘度降低,电导率升高.研究工作揭示了水对Bpy]BF4中各组分的存在形式、相互作用及其对体系物理化学及输运性质的影响,为其在冶金与材料制备方面的应用提供理论依据和参考.

Effect of Water on Structure and Properties of Room Temperature Molten Salts 1-Butylpyridinium Tetrafluoroborate

The structure and properties of room temperature molten salts 1-butylpyridinium tetrafluoroborate （Bpy]BF4）with different molar fraction of water between 0.05 ~0.95 are studied by molecular dynamics simulation at 298.1 5 K and 0.1 MPa.The densities,radial distribution functions,coordination number,spatial distribution functions,self-diffusion coefficients,conductivities and vis cosities of system are then obtained and analyzed.The simulation results show that the simulated densities agree well with the experimental results.The radial distribution functions and coordination number of different components regularly change in the systems. The spatial distribution functions are visualized to depict the microstructures of different components in the system.The interaction between the cation and anion become weaker while the interaction of water with anion, cation and other water molecules increase respectively.With the increa sing of water mole fraction,the self-diffusion coefficients of the water,cation and anion increases,the viscosity decreases and the conductivity increases.The effects of water on the forms of ions,different components of interactions and transport properties are revealed in Bpy]BF4 ,which provides theoretical basis for application of ionic liquids in metallurgy and material preparation.