Density Functional Theory Study of the Molecular Interaction between Selective Phenolic Compounds and Glycerol-Based Deep Eutectic Solvents

Abstract

In this work, the global scalar properties, including the highest occupied orbital energy (HOMO), lowest unoccupied orbital energy (LUMO), global softness (S), hardness (η), electronegativity (χ), and electrophilicity index (ω) of the different salts of choline chloride [CHCL], tetra butyl ammonium bromide [TBAB], tetra methyl ammonium chloride [TMAC], tetra butyl phosphonium bromide [TBPB], tetra butyl ammonium chloride [TBAC] with glycerol [GLY], and these different combinations of deep eutectic solvents (DESs) with cardanol, were predicted using density functional theory in Gaussian 03 software (DFT theory). Furthermore, the sigma profile and sigma potential of all the studied DESs, technical cashew nut shell liquid (Tech.CNSL), natural cashew nut shell liquid (Natural.CNSL), and their phenolic compounds such as anacardic acid, cardanol, cardol, and 2-methyl cardol were generated using COSMO-RS model in COSMOThermX software in order to understand the molecular behavior of different salt combinations with glycerol for the removal of phenolic compounds from their mixtures in CNSL without affecting the individual compound structural configuration at the molecular level. Finally, the best DES was screened for the removal of selective phenolic compounds of cardanol from CNSL via the DES-based extraction process.