In search of better replacement for highly polar volatile organic solvents, ionic liquids (ILs) with high polarity and high polarizability were synthesized using N-1 substituted 1,2,4-triazolium-based cation with trifluoromethanesulfonate as the counter anion. The temperature dependence polarity of the synthesized ILs has been investigated using solvatochromic dyes and expressed in terms of and Kamlet-Taft parameters (dipolarity/polarizability (π*), hydrogen bond donor acidity (α), and hydrogen bond basicity (β) in the range of (293.15−353.15) K. The introduction of the –SO3H functional group and triazole ring on the cation has revealed high polarity (ETN &gt; 1.2) and high polarizability (π*&gt; 3.2). Furthermore, to understand the extent of intermolecular interaction temperature dependence refractive indices have been measured in the temperature range (293.15−343.15) K and a positive correlation was observed with polarity parameter. 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 which is scrutinized to understand the solvation capability and intermolecular interaction in ILs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Ramesh L. Gardas

Department Of Chemistry

Dharmendra Singh

Gyanendra Sharma

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

ChemistrySelect

The solvation strength of N,N-dialkylethanolammonium based protic ionic liquids (PILs) have been determined by normalised Reichardt's parameter (ENT) and molecular polarizability (αP). The solvation strength depends on the intermolecular interactions which are governed by the functional group and molecular structure of the species. So here in this work, the influence of functional groups such as –OH, –RCOOH and –R, on solvatochromic parameters of studied PILs have been discussed in terms of experimental results and relevant literature. Further the intermolecular interactions of PILs have been analyzed with the help of temperature dependant experimental refractive index data. Additionally, a positive correlation was obtained between the polarity and the refractive index of the studied PILs. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Influence of Alkyl Substituent on Optical Properties of Carboxylate-Based Protic Ionic Liquids

The essential properties of ionic liquids (ILs) for various applications can be tuned by changing the combination of cations or anions in ILs. This work demonstrates how the structure variations effect the physicochemical, rheological and solvatochromic properties of protic and aprotic ionic liquids. For this, a set of four ionic liquids have been synthesized and characterized through spectral techniques. Thermal stability and phase behaviour of ILs have been analyzed by TGA and DSC. The experimental density, speed of sound and viscosity have been measured as a function of temperature from 293.15 to 343.15 K and an attempt has been made to distinguish the crucial role of counter ions on measured properties. Further, the fluidity and polarity behaviour of hydroxyl ammonium based protic or 1-alkyl-1,2,4-triazolium based aprotic cation and fluorinated anions were investigated through their rheological and polarity parameters at 298.15 K and discussion have been made on the basis of columbic and hydrogen bonding interactions. Interestingly, we found that anions have dominant effect on studied physicochemical properties irrespective of protic/aprotic nature of ionic liquid while the contribution of cations were vital for solvatochromic and rheological properties. Additionally, the ion-pair interaction energy, dipole moment and hydrogen bonding interactions of studied ILs have been analysed using density functional theory (DFT) calculations to support the experimental findings. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Effect of Fluorinated Anion on the Physicochemical, Rheological and Solvatochromic Properties of Protic and Aprotic Ionic Liquids: Experimental and Computational Study

In order to analyze the extent of solvation behaviour and stability of ascorbic acid (AA) in water or aqueous ionic liquid (IL) solutions, the knowledge of their thermodynamic properties is prerequisite which gives an appropriate idea about interactions involved in solutions. In addition, experimental and derived thermodynamic data is essential in effective process and product design involving these systems. In this report, we studied the volumetric and acoustic properties of AA in aqueous solution of synthesized IL, [HxTzm][CF3SO3] i.e. (1-Hexyl-4-(4-sulfobutyl)-1H-1,2,4-triazol-4-ium trifluoromethanesulfonate) in temperature range of (293.15–328.15) K and at atmospheric pressure. Further, the experimentally measured thermodynamic properties were used to calculate apparent molar and partial molar properties, which elucidate the solvation behaviour of AA in presence of studied IL. Further, on the basis of the structural interaction model, various type of interactions which is stirring between AA and IL have been discussed in terms of partial molar properties at infinite dilution, transfer parameters and pair and triplet interaction coefficients. © 2017 Elsevier B.V.

Journal of Molecular Liquids

Exploration of the solvation behaviour of ascorbic acid in aqueous solutions of 1,2,4-triazolium based ionic liquid

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.

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ISSN	23656549
Open Access	No