Measurements and Molecular Interactions for N,N-Dimethylformamide with Ionic Liquid Mixed Solvents

• Published in: The journal of physical chemistry. B 2010-05, Vol.114 (18), p.6126-6133
• Main Authors: Attri, Pankaj, Reddy, P. Madhusudan, Venkatesu, P, Kumar, Anil, Hofman, T
• Format: Article
• Language: English
• Subjects: B: Statistical Mechanics, Thermodynamics, Medium Effects
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp101209j

To understand the molecular interactions between N,N-dimethylformamide (DMF) with two families of ionic liquids (ILs), we have measured thermophysical properties such as densities (ρ) and ultrasonic sound velocities (u) over the whole composition range at 25 °C under atmospheric pressure. The excess molar volume (V E) and the deviation in isentropic compressibilities (ΔK s) were predicted using these properties as a function of the concentration of IL. These results are fitted to the Redlich−Kister polynomials. The materials investigated in the present study included two families of ILs such as ammonium salts and imidazolium salts. Diethylammonium acetate ([Et2NH][CH3COO], DEAA), triethylammonium actetate ([Et3NH][CH3COO], TEAA), triethylammonium dihydogen phosphate ([Et3NH][H2PO4], TEAP), and triethylammonium sulfate ([Et3NH][HSO4], TEAS) are ammonium salts and 1-benzyl-3-methylimidazolium chloride ([Bmim][Cl]) belongs to the imidazolium family. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion−dipole, ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors.