Synthesis, characterization and the effect of temperature on different physicochemical properties of protic ionic liquids

Abstract

In this work, eleven protic ionic liquids (PILs) containing different cations and anions were prepared and their physicochemical properties were measured. All PILs's structures were confirmed by NMR and elemental analysis (CHNS) were carried out. The physicochemical properties such as density, surface tension, viscosity and thermal degradation behaviour were measured, and the effect of cation/anion was investigated. The density and viscosity were measured within the temperature range of 293.15-373.15 K at atmospheric pressure. The thermal expansion coefficient values were calculated from the density data. Surface tensions were measured in the temperature range of 293.15 to 353.15 K and further the values were used to estimate the surface entropy and enthalpy of the ionic liquids at 303.15 K. The boiling and critical temperature were also estimated according to the Eötvos and Rebelo methods.The refractive indices were measured within the temperature range of 293.15 to 323.15 K.The thermal gravimetric analysis was performed in the temperature range of 373.15-773.15 K.

Optimization of OPEFB lignocellulose transformation process through ionic liquid [TEA][HSO4] based pretreatment

“…Figure 3 A is an H-NMR spectra of IL [TEA][HSO4]. Based on the literature approach, there are similarities in the chemical shift values, δ (ppm) with those reported by 40 , 41 at δ = 1.217–1.236 (N–CH 2 –CH 3 ), 3.005–3.023 (–H), 3.427–3.445 (N–H + ) and 3.867 (N + H 3 ). The similarity in chemical shift values characterizes the success of the IL [TEA][HSO 4 ] synthesis process based on the one-spot method.…”

“…Based on the IR spectra, we observed the appearance of new spectra at wave numbers of 2814.97 cm −1 , 1401.07 cm −1 , 1233.30 cm −1 and 847.92 cm −1 . The results of the literature study show that the values of the wave numbers refer to the NH, CH 3 , CN and SO 2 groups, respectively 41 . In addition, the success of the IL [TEA][HSO 4 ] synthesis process was confirmed by the shift in the absorption peak for wave number 1438 cm −1 to 1474.93 cm −1 which characterized the CH 2 functional group, as well as the shift in wave number 1048.18 cm −1 to 1063.00 cm −1 which characterizes the SO functional group.…”

Ionic liquids and deep eutectic solvents for the recovery of phenolic compounds: effect of ionic liquids structure and process parameters

“…The selection of ion pairs plays a major role in the thermo-physical properties as well as the solubility and miscibility of ILs in various organic and inorganic solvents. 90,91,[99][100][101][102] The physical properties such as density, surface tension, thermal properties, refractive index, viscosity, and acidity are key factors in the design and performance of ILs based industrial processes. 122,123 These physicochemical properties can be tuned to a greater extent either by changing the cation or the anion.…”

“…Literature review reveals that acyclic cations such as phosphonium, ammonium, sulphonium, cholinium, and cyclic cations such as imidazolium, pyridinium, pyrrolidinium, and piperidinium, are employed in the design of ILs (Fig. 2) 87,89,101,[104][105][106] with imidazolium cations being the most extensively studied. 104 On the other hand, more exibility is available for the selection of anions since these could be inorganic, such as halides, cyanate, phosphate, sulfate, nitrate, borate, as well as organic, such as phenolate, benzoate, malonate, and amines (Fig.…”

The relation between crystal structure and the occurrence of quantum-rotor induced polarization

“…g-Picoline hydrochloride (2) was commercially available (Carbosynth Limited), while g-picoline nitrate (3) and g--picoline hydrosulfate (4) were synthesized according to instructions from and (Ullah et al, 2015).…”