Study on Physicochemical Properties of Ionic Liquids Based on Alanine [C_nmim][Ala] (n = 2,3,4,5,6)

Abstract

According to Fukumoto's method, a new series of ionic liquids (ILs) based on alanine, [Cnmim][Ala] ( n=2,3,4,5,6), which comprise 1-alkyl-3-methylimidazolium cation ([Cnmim](+)) and alanine anions ([Ala] (-)), were prepared and characterized. In terms of standard addition method, the density and surface tension of amino acid ILs [Cnmim][Ala] (1-alkyl-3-methylimidazolium alpha-aminopropionic acid salt) were measured in the temperature range 293.15-343.15+/-0.05 K. The volume and surface properties of the ILs [Cnmim][Ala] were discussed. A new method of determining parachor of ionic compound was proposed and was applied to estimate the physicochemical properties of amino acid ionic liquids (AAILs): molecular volume, surface tension, molar enthalpy of vaporization, and thermal expansion coefficient. In comparison with Deetlefs's method of using neutral parachor contribution, the method proposed in this work makes smaller error in estimating properties of AAILs.

Prediction of the thermodynamic properties of 1-alkyl-3-methylimidazolium lactate ionic liquids [C n mim][Lact] (n = 2, 3, 4, 5, and 6) by parachor

“…Plots of the experimental values of ln  of the ionic liquid [24], the contribution to molecular volume per methylene (CH 2 ) group was found to be 0.0278 nm 3 , which is in good agreement with a mean contribution of 0.0275 nm 3 per methylene group obtained by Glasser [23] using the ionic liquids [C n mim][BF 4 ] and [C n mim][NTf 2 ]. This suggests that the contribution of per methylene group to the volume may be treated as a constant so that we can use the mean value, 0.0278 nm 3 , to predict the volumetric properties of other ILs which are homologues of [C n mim][Lact] (n = 2, 3, 5, and 6).…”

“…Considering that each methylene group in the alkyl chains of imidazolium-based ionic liquids has almost the same chemical environment, we have put forward a semiempirical method for predicting P of IL homologues [24], using the sum of the experimental value for [C 4 mim][Lact] and contributions from the methylene groups. In this way, the values of the parachor for the homologues of ILs [C n mim][Lact] (n = 2, 3, 4, 5 , and 6) can be predicted from the formula (521.0 + 37.5 n), where n is the number of methylene groups; the contribution per methylene to the parachor of 37.5 was obtained in our previous paper [24].…”

Synthesis and Thermophysical Properties of Hydrogensulfate Based Acidic Ionic Liquids

“…Experimentally measured densities can be used to calculate the molecular volume of the synthesized ILs (at 298.15 K and p = 0.1 MPa) using Eq. 4 [23,24]:…”

Study On The Structures And Interactions Binary System Composed By The Ionic Liquids [Bmim][Ala] and Water /Methanol Using The Vibrational Spectra

“…Extensive experimental studies have been performed on ILs and AAILs [16][17][18]. However, it is far from enough to summarize a general rule that can predict the physicochemical properties of the ILs for a specific application [19]. Because the features that control the physicochemical properties of ILs remain poorly understood.…”

“…A set of theoretical methods have now been used to study ILs. Traditional molecular dynamics simulations, first-principles molecular dynamics simulations and electronic structure methods have been applied to ILs to obtain useful information on ILs [19,20].…”