Ionic Parachor and Its Application II. Ionic Liquid Homologues of 1-Alkyl-3-methylimidazolium Propionate {[C_nmim][Pro] (n = 2–6)}

Abstract

Five propionic acid ionic liquids (PrAILs) [C(n)mim][Pro] (n = 2-6) (1-alkyl-3-methylimidazolium propionate) have been prepared by the neutralization method and characterized by (1)H NMR spectroscopy and differential scanning calorimetry (DSC). Their density, ρ, surface tension, γ, and refractive index, n(D), were measured at (298.15 ± 0.05) K, and the experimental values of parachor for the PrAILs were calculated. Using the parachor values of [C(n)mim](+) obtained by Guan et al., the anionic parachor values of [C(n)mim][Pro] (n = 2-6), [C(2)mim][RBF(3)] (R = N-C(n)H(2n+1) (n = 1-5)), [C(n)mim][Gly] (n = 2-6), and [C(n)mim][PF(3)(CF(2)CF(3))(3)] (n = 1-6) were determined. Then, the parachor, surface tension, and refractive index of the ILs investigated in this work were estimated. The estimated values correlate quite well with the corresponding experimental values.

Physico-chemical Properties of 1-Alkyl-3-methylimidazolium Propionate Ionic Liquids {[Cnmim][Pro](n = 3, 4, 5, 6)} from 288.15 K to 328.15 K

“…From Table , the values of density in this work are closed to that in the literature . The values of density for [C n mim][Pro] ( n = 3,4,5,6) at 298.15 K in our previous work were larger and we presume that the newer values of density are preferred.…”

“…In recent years, there has been a developing trend in the literature toward estimation of the physicochemical properties for compounds by semiempirical methods, in particular, for ILs. − Although the estimated result cannot be regarded as accurate physicochemical data, it is commended because it provides valuable insight into the origins behavior of materials. As a continuation of our previous investigation, , this paper reports the following: (1) Four propionic acid ionic liquids [C n mim][Pro] ( n = 3, 4, 5, 6) (1-alkyl-3-methylimidazolium propionic) were prepared and characterized. (2) The values of density, surface tension, and refractive index for [C n mim][Pro] ( n = 3,4,5,6) were measured in the temperature range of 288.15–328.15 K. Since PrAILs can strongly form hydrogen bonds with water, which is the problematic impurity, the standard addition method (SAM) was applied in these measurements .…”

Determination of the Enthalpy of Vaporization and Prediction of Surface Tension for Ionic Liquid 1-Alkyl-3-methylimidazolium Propionate [Cnmim][Pro](n = 4, 5, 6)

“…In addition, x n = Δ H v n /Δ g l H o m (298) in eq . Using the experimental data in our previous paper, the values of δ μ for [C n mim]­[Pro]­( n = 4, 5, 6) were calculated from eq and are listed in the fourth column of Table . From Table it can be seen that the values of δ μ decrease with the increasing number of methylene (−CH 2 −) groups in the alkyl chains of the ILs, that is, the polarity of the IL reduces with the increase of the number of methylenes.…”

Physicochemical Properties of Proteomic Ionic Liquids Matrices for MALDI-MS

“…This value depends on the molecular volume. It is important to mention that the transport properties of the ionic liquids depend on the cation moieties [31]. Because the high molecular weight of SA-ILMs compared to DHBILMs for the same pyridinium cation, the former showed high density over the latter.…”