Low-Viscosity Tetramethylguanidinum-Based Ionic Liquids with Different Phenolate Anions: Synthesis, Characterization, and Physical Properties

Abstract

A new series of low-viscosity tetramethylguanidinum-based ionic liquids (ILs) with various substituted phenolate anions were prepared and characterized using nuclear magnetic resonance and Fourier transform irnfrared spectroscopy, elemental analysis, differential scanning calorimetry analysis, and thermogravimetry. Their densities, viscosities, refractive indices, and electrical conductivities were measured and correlated with thermodynamic and empirical equations in the temperature range of (298.15 to 343.15) K under ambient conditions. The effects of substituent groups in phenolate anions on these physical properties were then discussed on the basis of structure. Furthermore, the thermal expansion coefficient was calculated from the experimental values of density, and the correlation between the viscosity and the molar conductivity was proposed by the Walden rule. These ILs are classified as “poor ionic liquids” and have a poor temperature dependency of the thermal expansion coefficient.

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

“…Ionic liquids provide a vapour less, good thermal stability, designable structures and recyclable green-solvent for many chemical reactions 2,3 . As reaction media, the application of ILs for a wide variety of synthetic processes is an area of intensive research.…”

“…Ionic liquids provide good thermal stability, designable structures, a recyclable green-solvent for many chemical reactions and they are vapourless. 2,3 ILs are also being used in a variety of applications viz. in the food industry, 4 extraction processes, 5 nuclear science, 6 biotechnology, 7 material engineering, 8 and as electrolytes in batteries, 9 fuel cells, 10 solar cells, 11 biosensors, 12 light emitting electrochemical cells, 13 etc.…”

Facile One-Pot Synthesis of Flavanones Using Tetramethylguanidinum-Based Ionic Liquids as Catalysts

“…The preparation process was similar to the procedure described in our previous work [15]. All the yields of these TMGILs were more than 90 %, and the structures of TMGILs were then confirmed by 1 H, 13 C NMR and FT-IR spectroscopy (available as the supplementary data).…”

Experimental investigation of CO2 absorption enthalpy in conventional imidazolium ionic liquids

“…It provides the pioneering idea of using functionalized ILs for gas separation. Subsequently, scholars have designed and synthesized various functionalized ILs from anions and cations, [11][12][13][14] grafting, 15,16 and other aspects. 17,18 Functionalized ILs significantly increase the amount of CO 2 absorption; [19][20][21][22][23] however, the high prices of these ILs increase investment and operating costs, which hinders their industrial applications.…”