Measurement Of Physicochemical Properties Of Serine Ionic Liquid And Semi-empirical Estimates

Two serine ionic liquids [Cnmim][Ser](n=3,4)(1-alkyl-3-methylimidazoliumserine) were prepared by the neutralization method and characterized by1H NMRspectroscopy and differential scanning calorimetry (DSC). Since the AAILs can formhydrogen bonds with water strongly, the small amounts of water are difficult toremove from the AAILs by common methods. In order to eliminate the effect of thetrace water, the standard addition method (SAM) was applied to these measurements.The values of their density, surface tension, refractive index, conductivity andviscosity were measured at the temperature range of (298.15to338.15±0.01) K withan interval of5K, and the density, surface tension, refractive index, conductivity andviscosity of pure ionic liquids[Cnmim][Ser](n=3,4) at298.15K were fitted using thestandard addition method (SAM).In terms of Glasser’s theory, the standard molar entropy and lattice energy of theILs at298.15K were calculated. Using Kabo’s method, the molar enthalpy ofvaporization of the ILs at298.15K, lgHm0(298K), were estimated. Using the valuesof refractive index of the ILs, the molar polarization and polarizability werecalculated. According to the interstice model, the thermal expansion coefficient of ILs,, were calculated and in comparison with experimental values, their magnitudeorders are in good agreement.The conductivity and viscosity of pure ionic liquids obtained by linear fittingand change law of it followed by temperature were gotten by the equation ofArrhenius and VTF. Electric conductance activation energy and molar conductivitywere gotten and diffusion coefficient was calculated by the equation ofNernst-Einstein. Viscous flow activation Gibbs free energy, ΔG≠, of serine ionic liquidwas calculated based on the equation of Eyring liquid viscosity theory.Compared with viscous flow activations calculated by the viscous flow activation Gibbs free energy and Arrhenius equation, respectively, both are in good agreement.Finally, on the basis of conductivity and viscosity, using the Walden rules, a lot of coefficient W of ionic liquids was calculated. The results showed that different ionicliquids have different coefficient W, which just is feature physical parameter.