The present study is focused on synthesis and physicochemical properties of a new class of Deep Eutectic Solvents (DESs) based on Benzyltripropylammonium chloride as hydrogen bond acceptor (HBA) and different hydrogen bond donors (HBD) like phenol, ethylene glycol, glycerol and lactic acid. Several physicochemical properties such as, density, speed of sound, conductivity and refractive index of these four DESs have been measured in the temperature range of 293.15–343.15 K and used to calculate various derived thermodynamic properties. Further, rheological measurements have been carried out to understand the viscosity and flow behavior of these DESs and also the influence of different hydrogen bonding environment on the nature of DESs. The temperature dependent density and viscosity values have been fitted using second order polynomial and well-known Vogel-Tammann-Fulcher (VTF) equations, respectively The experimental results implies that both the type of HBD and temperature has significant influence on the physicochemical characteristics of the synthesized DES. © 2017 Elsevier B.V.

Ramesh L. Gardas

Department Of Chemistry

Anusha Basaiahgari

Somenath Panda

Density (specific gravity)

Ethylene

Ethylene glycol

Eutectics

Lactic acid

Organic solvents

Refractive index

Rheology

Solvents

Temperature

Viscosity

Deep eutectic solvents

Isentropic compressibility

PHYSICOCHEMICAL CHARACTERISTICS

Physicochemical property

Rheological measurements

Second-order polynomial

Temperature-dependent density

WALDEN PLOT

Hydrogen bonds

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Fluid Phase Equilibria

Despite the recent advancements in the field of deep eutectic solvents (DESs), their high viscosity often prevents practical applications. A versatile strategy to overcome this problem is either to add a co-solvent or to confine the DES inside a nanoscaled self-organized system. This work assesses the microstructures of a hydrated and nanoconfined DES comprising benzyltripropylammonium chloride [BTPA]Cl and ethylene glycol (EG). They act as a hydrogen-bond acceptor and a donor, respectively. The hydrogen bonding between [BTPA]Cl and EG in the DES (i.e., BTEG) and the molecular states of water in the hydrated BTEG were studied by Raman spectroscopy. The results show different hydrogen-bonding associations between water-water and water-BTEG or EG molecules. In addition, we investigated the confinement effects of BTEG in a Polysorbate 80 (Tween-80)/cyclohexane reverse micellar (RM) system. The results are compared with those of an ionic liquid-encapsulated RM system. The formation, bonding characteristics, and thermal stability of the RM droplets were studied by solubilization, dynamic light scattering, rheology, and Raman spectroscopy experiments. Furthermore, it is shown that hydrogen bonding between the DES and the surfactant leads to a stable RM system. Interestingly, the viscosity of the RM system is significantly lower than that of the neat DES suggesting that DESs have a much wider practical applicability in the form of RMs. Copyright © 2019 American Chemical Society.

Fulltext

Journal of Physical Chemistry B

Molecular-Level Insights into the Microstructure of a Hydrated and Nanoconfined Deep Eutectic Solvent

In the maneuver to achieve desulfurization, we have explored various nitro-substituted positional isomeric imidazolium-based aprotic ionic liquids (ILs). Ortho-, meta-, and para-substituted nitro benzyl group-aided imidazolium-based ILs were synthesized and used to understand the extractive desulfurization (EDS) efficiency of fuels. ILs chosen for the experiment were optimized using the B3LYP method and 6-311(++)g(d,p) of Gaussian 09, and their interactions with thiophene derivatives were analyzed using the integrated electric field polar continuum model solvation. Free energy of solvation provided qualitative information about the ability of ILs to achieve desulfurization. Parameters affecting the efficiency of synthesized ILs were perused, such as the effect of IL volume, concentration, duration of rotation, and other such parameters. Lewis acidity, availability of the Lewis acidic site and π-πinteraction influenced the EDS efficiency of ILs. Copyright © 2019 American Chemical Society.

Energy and Fuels

Effect of Nitro Groups on Desulfurization Efficiency of Benzyl-Substituted Imidiazolium-Based Ionic Liquids: Experimental and Computational Approach

Deep eutectic solvents (DESs) are regarded as a promising and emerging alternative for volatile organic compounds (VOCs) due to their cost-effectiveness and environmentally sustainable nature. Formulation of new DESs and thorough investigation of their physicochemical properties have been on the rise ever since potential applications of DES have been realized. The present study reports a new series of DES based on benzyltrimethylammonium chloride and benzyltributylammonium chloride as hydrogen bond acceptor (HBAs) with three ethylene glycols and glycerols as hydrogen bond donors (HBDs). The current work includes the synthesis, characterization, and investigation of the thermophysical properties of a series of DES systems. The studied properties include density, ρ, speed of sound, u, viscosity, η, refractive index, nD, and electrical conductivity, σ, for all DESs in the temperature range from 283.15 to 343.15 K. The observed trends in properties like density, speed of sound, viscosity, and refractive indices were correlated with appropriate equations, and some industrially useful parameters have also been derived. An insight about the internal association in these DESs has been analyzed through the rheological and Fourier-transform infrared (FT-IR) spectroscopy. The newly synthesized DESs have also been investigated for their efficiency in aqueous biphasic system (ABS) formation. This systematic study revealed the influence of both HBD/HBA and temperature on the physicochemical characteristics of the DESs. Copyright © 2018 American Chemical Society.

Journal of Chemical and Engineering Data

Effect of Ethylene, Diethylene, and Triethylene Glycols and Glycerol on the Physicochemical Properties and Phase Behavior of Benzyltrimethyl and Benzyltributylammonium Chloride Based Deep Eutectic Solvents at 283.15-343.15 K

Interpreting the physiochemical properties and structure-property correlations of ionic liquids (ILs) is a key to the enlargement of their optimized structures for specific applications. In this work, a series of ILs based on 1-alkyl-1,2,4-triazolium cation with trifluoromethanesulfonate anion were synthesized and the effect of cation and temperature on physiochemical properties such as density, viscosity, speed of sound, conductivity, and rheology was studied. Temperature dependence densities were correlated with the densities estimated by the Gardas and Coutinho model, whereas viscosity and molar conductivity have been found to satisfy the Vogel-Tammann-Fulcher (VTF) equation over the studied temperature range 293.15-343.15 K. Further, to explore the wide range of applications, ionicity has been tested by correlating the fluidity with molar conductivity and it was found that synthesized ILs can be referred to as "good ILs". Furthermore, the fluidity behavior describing the interactions between the cation and anion of ILs was investigated through their rheological properties, and the Newtonian behavior of ILs has been examined by varying the effect of shear rate on viscosity. Finally, the impact of structure variants in terms of the N-1 functionalized 1,2,4-triazole ring has been analyzed over the studied properties. © 2016 American Chemical Society.

Influence of Cation Size on the Ionicity, Fluidity, and Physiochemical Properties of 1,2,4-Triazolium Based Ionic Liquids

N,N-dimethylethanolammonium (DMEA) based ionic liquids with carboxylate anions are very important in organic synthesis, gas absorption, biological and pharmaceutical applications. The fundamental physiochemical properties will give a platform to better understanding of their nature for scientific community. Here in this work, five DMEA based protic ionic liquids (PILs) with carboxylates were synthesized and their physicochemical properties such as density (ρ) and speed of sound (u) were measured as a function of temperature from (293.15-343.15) K at 0.1 MPa pressure. Several derived thermophysical properties such as molecular volume (Vm), standard entropy (S°), isothermal expansion coefficient (α) and isentropic compressibility (βs) have been calculated using experimental data. The effects of carboxylate anion chain length and temperature on physicochemical properties have been discussed. The crystal potential energy (UPOT) of ionic liquid compared with MX type of inorganic salt and discussed for ion interaction in PILs. © 2016 Elsevier B.V.

Effect of anion chain length on physicochemical properties of N,N-dimethylethanolammonium based protic ionic liquids

In this work, a new series of low viscous protic ionic liquids based on N-methylpyrrolidone cation and carboxylate anions with different chain length has been synthesized and characterized. Density, speed of sound and viscosity have been measured for these ionic liquids in the temperature range from 293.15 to 343.15. K. The density data have been fitted to linear equation as well as correlated with group contribution method developed by Gardas and Coutinho. From the density correlation, molecular volume data for cation and anion constituents of studied ionic liquids have been proposed. By using experimental density and speed of sound data, the isentropic compressibility, coefficient of thermal expansion, standard entropy, intermolecular free length and lattice energy have been calculated for studied ionic liquids. Viscosity data were correlated with the Vogel-Tammann-Fulcher equation. To understand the nature of the ionic liquids and structure-property relationship, the effect of anion alkyl chain length has been studied and correlated. Ionic liquids studied in this work are comparatively cheaper in price and can be promising in bio-macromolecule solubilization and other commercial fields. © 2014 Elsevier B.V.

Measurement and correlation for the thermophysical properties of novel pyrrolidonium ionic liquids: Effect of temperature and alkyl chain length on anion

We report a systematic study to understand the structural dependence of protic ionic liquids, having ammonium or hydroxylammonium as cation and carboxylate as anion, on surface, optical, and transport properties. Experimental measurements of surface tension, refractive index, and electrical conductivity were investigated in the temperature range from (293.15 to 333.15) K at atmospheric pressure to understand the effect of the hydroxyl group on the cationic part and alky chain length and inclusion of highly electronegative fluorine atoms on the anionic part of studied protic ionic liquids. Further, surface entropy, surface energy, critical temperature, parachor, molar refraction, electronic polarizability, thermo-optic coefficient, and free volume were estimated from experimental values. Experimental electrical conductivity data were correlated using the Vogel-Tammann-Fulcher equation. The ionicity was assessed on the basis of the fractional Walden rule, and it was found that the studied protic ionic liquids fall below the ideal line. Upon hydroxyl group functionalization on the cationic chain length, the surface tension and refractive index of ionic liquids increase significantly, whereas the electrical conductivity decreases over the nonfunctionalized ionic liquid counterpart. Moreover, experimental and calculated results were explained to understand the effect of temperature and moiety of ionic liquid on studied thermophysical properties. © 2015 American Chemical Society.

Structural Dependence of Protic Ionic Liquids on Surface, Optical, and Transport Properties

In this work, five protic ionic liquids having propylammonium, 3-hydroxy propylammonium as cations and formate, acetate, trifluoroacetate as anions have been synthesized. Thermophysical properties such as density (ρ), viscosity (η) and sound velocity (u) have been measured at various temperatures ranging from (293.15 to 343.15) K at atmospheric pressure. The experimental density and viscosity were fitted with second order polynomial and Vogel-Tamman-Fulcher (VTF) equations, respectively. Also experimental densities were correlated with the estimated density proposed by Gardas and Coutinho model. The coefficient of thermal expansion (α) and isentropic compressibility (βs) values have been calculated from the experimental density and sound velocity data using empirical correlations. Lattice potential energy (UPOT) has been calculated to understand the strength of ionic interaction between the ions. Thermal decomposition temperature (Td) and glass transition temperature (Tg) along with crystallization and melting point were investigated using TGA and DSC analysis, respectively. The effect of alkyl chain length and electronegative fluorine atoms on anionic fragment as well as hydroxyl substituent on cationic side chain in the protic ionic liquids has been discussed for studied properties. The effect of ΔpKa over the studied properties has also been analyzed. © 2014 Elsevier Ltd. All rights reserved.

Journal of Chemical Thermodynamics

Thermophysical properties of ammonium and hydroxylammonium protic ionic liquids

Acoustic, volumetric, transport, optical and rheological properties of Benzyltripropylammonium based Deep Eutectic Solvents

Journal	Data powered by TypesetFluid Phase Equilibria
Publisher	Data powered by TypesetElsevier B.V.
ISSN	03783812
Open Access	No