Molecular Interactions of Systems Containing Ionic Liquids: Thermodynamic, Spectroscopic and Computational Study

• Grant number: 24/17380-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2025
• End date: February 28, 2026
• Field of knowledge: Engineering - Chemical Engineering - Chemical Process Industries
• Principal Investigator: Ricardo Belchior Tôrres
• Grantee: Isabela Ornelas Aravena
• Host Institution: Centro Universitário FEI (UNIFEI). Campus de São Bernardo do Campo. São Bernardo do Campo , SP, Brazil

Abstract

Ionic liquids (ILs) are part of a set of salts with low melting point with applications as solvents, as catalysts, as thermal fluids, in separation processes, in batteries, among other. Thermodynamic analyses concerning pure substances and mixtures are of great importance in projects of chemical processes. The fit of an Equation of State to the experimental data of thermodynamic properties enables posterior application in the prediction of other properties in several conditions. Moreover, the determination of excess thermodynamic functions, especially supported by studies involving Quantum Chemistry and spectroscopic analyses, significantly contribute to quantify and understand the behavior of interactions between the substances. Due to the scale of applications verified for the ILs, thermodynamic studies are essential for projects and simulations of processes involving them. The present project aims to perform these studies, experimentally and computationally, for mixtures containing the ILs n-butylammonium methanoate, n-butylammonium acetate and n-butylammonium propanoate, and water, with the objective of analyzing quantitatively and qualitatively interactions between the substances involved. Results of such analyses are typically inserted in process simulators, being the basis for its operation. In this project, ILs will be synthesized and characterized, and experimental measurements of density, viscosity, and speed of sound will be performed. These results will be used to calculate some thermodynamic properties, including excess molar volume, viscosity deviation, excess Gibbs activation energy, and compressibility deviation. Furthermore, a spectroscopic study (Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopies) of the proposed mixtures (ILs + water) will be performed in order to try to identify possible inter and intra molecular interactions between the chemical species present in the mixtures. Finally, a computational study of Quantum Chemistry based on Density Functional Theory (DFT) will be performed, so that the results (experimental and computational) will be quantified and analyzed in terms of interactions between the compounds involved in the mixtures.