| Due to the special physical and chemical properties of ionic liquids, IL has a broad application such as biochemistry, pharmaceutical chemistry, organic synthesis, extraction and separation, electrochemistry, catalysis and so on, and become one of the multi-disciplinary, very active in the forefront of research. The reason why the ionic liquid aroused so much enthusiasm is the special nature of ionic liquids with other organic solvents are not available, it is consistent with the environment-friendly concept in the current word. The design of ILs is different from other solvents, we can compose ions according to the needs of target.Theoretical simulation is an important means of Ionic Liquid multiscale static and dynamic structures. The anisotropic of ionic liquid make critical polarization effect, through short-range, long-range interaction, polarization effects directly affect the thermodynamic properties of ionic liquids, transport properties and spatial distribution. The EEM/MM polarizable force field for IL systems is derived from combined EEM and MM. In this study, the electronegativity and hardness calibrations of the EEM/MM model, particularly for [Cnmim][Gly](n=1-4) with alkyl substituents of different lengths, were employed. There are two points:(1) The EEM/MM model describes the electrostatic interactions of atoms and their changes in different ambient environments;(2) Clearly considering the H-bond interaction and posed the expression of kHB(RHB) in the HBIR that significant for the H-bond interaction. This understanding led us to develop a general EEM/MM fluctuating charge-polarizable force field for IL systems. The EEM/MM polarizable force field was developed by determining the electronegativity and hardness parameter calibrations, particularly for the serial imidazolium cations. Gas-phase [Cnmim]+, [Gly]-, [Cnmim][Gly] ion pairs, and liquid-phase [Cnmim][Gly](n = 1-4) were used to apply the EEM/MM. The effects of polarization on the structural and thermodynamic properties of the [Cnmim][Gly] were further discussed. Used the set of parameters can accurately determine the charge distribution of the molecule, the charge of all atoms and the transfer of charge can calculated. The EEM / MM model takes into account the interaction of hydrogen bonds, Introduces a more specific constant kHB(RHB), it is very important to discuss the interaction of hydrogen bonds in AAILs. We used the EEM/MM model to calculate the properties of gas-phase [Cnmim]+, [Gly]- and [Cnmim][Gly](n=1-4) ion pairs and the molecular dynamics simulations.Great concern to the scientific community for the ionic liquid has expanded from pure ionic liquid to the range of mixed ionic liquids. The resultant mixtures were found to broadly obey the ideal mixing law; where exceptions arose, excess molar volumes were small and positive, indicating an absence of new strong interactions in the mixture. But now the concern point mostly in thermodynamics, and more of aprotic ionic liquids. However, there is few research on the thermodynamics of mixed ionic liquids, in particular the molecular dynamics simulations. In this paper, we combined the [Bmim][BF4]with the [Bmim][PF6] and water, then obtain the density, enthalpy of vaporization and radial distribution function from the molecular dynamic simulations, which are found to be reasonably consistent with experiment results, and the results show that with increasing water content the density decreasing. From the molecular dynamic simulations, we can get two conclusions:(1) the structural features between hydrophilic ionic liquids and water;(2) the structural features between hydrophobic ionic liquids and water. |
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