Synthesis and Thermophysical Properties of Imidazolium-Based Bronsted Acidic Ionic Liquids

Abstract

A range of imidazolium-based Bronsted acidic ionic liquids (ILs) have been synthesized by varying the side chain length of the alkyl and alkyl sulfonic group incorporated to the C1 and C3 positions in the imidazolium ring respectively with a fixed HSO4 – anion. The synthesized ILs were characterized using NMR for structure confirmation and CHNS for elemental analysis. The thermal properties such as thermal decomposition temperature were determined using thermogravimetric analysis, and several key physical properties such as viscosity and density were measured within a temperature range of 20 °C to 80 °C using an Anton Paar viscometer and densitometer. The density measurement results and established equations were used to calculate the molecular volumes, standard entropies, crystal lattice energies, and thermal expansion coefficients of the synthesized ILs.

Acidic Ionic Liquids

“…This study provides some useful information for further research and applications of AILs. 303 In 304 The density and viscosity of these ILs are shown in Table 4, whereas molecular volume V m , standard entropy S 0 , thermal expansion coefficient (α p ) and crystal energy UPOT are shown in Table 5.…”

“…316 There are attempts to correlate calculated H 0 values of BAILs with catalysis activities in chemical reactions such as, Pechmann a Standard uncertainty u is u(T) = 0.01 °C and the combined expanded uncertainty is u c (ρ) = 3 × 10 −4 g/cm 3 , u c (η) = 0.4% mPa•s (level of confidence = 0.95). 304 Table 5. Molecular Volume, V m , Crystal Energy (UPOT), Thermal Expansion Coefficient (α p ), and Standard Entropy (S 0 ) of Selected BAILs at 20 condensation, 317 hydration of alkynes, 177 Fischer indole synthesis, 318 coupling of epoxides and CO 2 , 319 alcoholysis of furfural alcohol to alkyl levulinates, 320 esterification, 321−324 fructone synthesis, 325 2-phenylbenzimidazole synthesis, 326 degradation of lignin model compounds, 327 acetal synthesis 328 and dehydration of fructose.…”

Extraction of lignin and quantitative sugar release from biomass using efficient and cost-effective pyridinium protic ionic liquids

“…This owes to the compatibility of size of interstices in the network of biomass and the size of ions of the IL. 29,30 We know that smaller particles can interact with IL molecules through a greater surface area, thus resulting in better delignication of biomass. A comparison of the effect of particle size and the extent of pretreatment (lignin extraction) is exhibited as graphs in Fig.…”

Hydrogen Bonding Interactions of m-Chlorotoluene with 1-Alkanol Analyzed by Thermodynamic, Fourier Transform Infrared Spectroscopy, Density Functional Theory, and Natural Bond Orbital

“…Therefore, in the pure liquid state, alkanol molecules are associated with hydrogen bonding as linear and chain aggregates, as can be seen in Figure S1. Also, 1-alkanols are cheap and used as solvents in a variety of chemical and technological processes. − Furthermore, the knowledge of excess thermodynamic properties of binary liquid mixtures containing halogenated hydrocarbons is very staple due to their practical applications in various fields, including detergents, rubber, plastics, and aerosol propellants . The m- chlorotoluene (MCT) solvent is one of the methyl substituted halo-benzenes that is used as an intermediate in pesticide pharmaceutical and dye industries …”