Temperature effect on the molecular interactions between ammonium ionic liquids and N,N-dimethylformamide

Area of Science:

• Physical Chemistry
• Solution Chemistry
• Thermodynamics

Background:

• N,N-dimethylformamide (DMF) is a highly polar solvent with diverse molecular interactions.
• Ammonium ionic liquids (ILs) exhibit significant intermolecular forces.
• Understanding mixtures of polar solvents and ILs is crucial for various chemical applications.

Purpose of the Study:

• To investigate the thermophysical properties of DMF-ammonium IL mixtures.
• To analyze molecular interactions and structural effects in these binary systems.
• To provide data for predicting solvent behavior and designing new materials.

Main Methods:

• Measurement of densities (ρ) and ultrasonic sound velocities (u) across the entire composition range.
• Calculation of excess molar volume (V(E)) and isentropic compressibility deviations (ΔK(s)).
• Fitting experimental data to Redlich-Kister polynomials for accurate modeling.

Main Results:

• Thermophysical properties were measured for mixtures of DMF with tetramethylammonium hydroxide (TMAH), tetraethylammonium hydroxide (TEAH), and tetrapropylammonium hydroxide (TPAH).
• Excess molar volumes and compressibility deviations indicated specific intermolecular interactions.
• Analysis elucidated the roles of ion-dipole, ion-pair, and hydrogen bonding.

Conclusions:

• The study provides a comprehensive understanding of molecular interactions in DMF-ammonium IL mixtures.
• Derived properties offer insights into the structural organization of these solvent systems.
• Results contribute to the fundamental knowledge of polar solvent-IL interactions.