Effects of ionicity and chain structure on the physicochemical properties of protic ionic liquids

Abstract

The physicochemical properties of protic ionic liquids (PILs) determine their industrial applications. In this study, six PILs based on 1‐vinylimidazole were synthesized, and their ionicities were determined by 1H NMR method. The thermodynamic properties, viscosities, densities, and conductivities of these PILs were correlated with the ionicities and the chain lengths of the anions. The ionicity was found to depend on the acidity of the alkyl carboxylic acid. Since HAc has the strongest acidity among these acid precursors, Vim·HAc has the highest ionicity and thus the strongest Coulombic interactions among the six PILs. The other five PILs have similar ionicities but different chain lengths in their anions. So, we can separately identify the effects of Coulombic interactions and van der Waals forces on the physicochemical properties of PILs. From these trends, the viscosity and conductivity of PILs may be tuned by varying the acidity and alkyl chain length of the precursors.

Performance and pressure drop ofCO2absorption into task‐specific and halide‐free ionic liquids in a microchannel

“…Nowadays, Ionic liquids (ILs) are being investigated as potential CO 2 absorbents due to their unique characteristics, 4,5 such as wide liquid temperature range, negligible vapor pressure, and good chemical stability. Meanwhile, ILs were also put forward as the most promising “green solvents” and played a catalytic role in some chemical reactions in view of their low melting point, good recyclability, good thermal stability, and tunable physical and chemical properties 6,7 .…”

Carbon dioxide capture by new DBU‐based DES: The relationship between ionicity and absorptive capacity

“…Some researchers have noticed a fact that the molecular state and ionic state coexist in a DES system. Although obviously, ionicity cannot be ignored, most studies only consider its correlation with physical properties of ILs 39‐41 . The effect of their co‐existence on absorption mechanism and the relationship between ionicity and absorption amount are worth discussing.…”

“…The effect of their co‐existence on absorption mechanism and the relationship between ionicity and absorption amount are worth discussing. With the development of this research area, various methods for the quantitative determination of ionicity have been developed 41‐46 . Recently, the group of Li proposed a quantitative determination of ionicity by active hydrogen chemical shift of Nuclear Magnetic Resonance (NMR), which has attracted a wide attention 41,46 .…”

Catalytic Conversion of CO2 from Simulated Flue Gases with Aminophenol-Based Protic Ionic Liquids to Produce Quinazoline-2,4(1H,3H)-diones under Mild Conditions

“…Although numerous homogeneous and heterogeneous catalysts such as alkali metal salts, organic superbases, ionic liquids (ILs), − bimetallic oxides, and supported nano-materials , have been developed for the transformation of CO 2 and 2-aminobenzonitriles into quinazoline-2,4­(1 H ,3 H )-diones, most of the reported catalysts still require a high temperature, a high CO 2 pressure, and a tedious separation process to obtain satisfactory product yields. In this regard, the ILs exhibit great development potential due to their excellent physical and chemical properties, such as non-volatility, high thermal stability, good solubility, and excellent catalytic activity. , By carefully designing the composition of ILs, they can show superior abilities for CO 2 activation and transformation . Up to now, the application of ILs as a reaction medium in the synthesis of quinazoline-2,4­(1 H ,3 H )-diones from CO 2 and 2-aminobenzonitriles has made great progress when compared with other catalytic materials.…”

“…In this regard, the ILs exhibit great development potential due to their excellent physical and chemical properties, such as non-volatility, high thermal stability, good solubility, and excellent catalytic activity. 24,25 By carefully designing the composition of ILs, they can show superior abilities for CO 2 activation and transformation. 26 Up to now, the application of ILs as a reaction medium in the synthesis of quinazoline-2,4(1H,3H)-diones from CO 2 and 2aminobenzonitriles has made great progress when compared with other catalytic materials.…”