First-Principles Prediction of Kamlet–Taft Solvatochromic Parameters of Deep Eutectic Solvent Using the COSMO-RS Model

Abstract

Rapid discovery of a deep eutectic solvent (DES) and its increasing application in various scientific applications demands a well-defined polarity scale for the new generation of eutectic solvents. The tunable nature of a DES facilitates to increase its number by combining various hydrogen bond acceptors and donors in multiple molar ratios. Therefore, the experimental measurement of polarity scale represented by solvatochromic parameters is a cumbersome task. In this context, we have developed a first-principle-based conductor-like screening model-real solvent (COSMO-RS)-derived predictive modeling approach to predict the Kamlet−Taft solvatochromic parameters of 26 hydrophilic and 62 hydrophobic DESs. The COSMO-RS-derived energies, that is, hydrogen bonding energy (E HB ), misfit energy (E MF ), and van der Waals energy (E VDW ), are linearly correlated with the experimental data set of 28 DESs having 4 choline chloride, 17 tetraalkylammonium organic salt, 4 menthol, and 3 betaine subclasses. A lowest root-mean-square deviation (rmsd) of 0.06% for the choline chloride class of DESs and a highest rmsd of 3.14% for the tetrabutylammonium chloride class of DESs are obtained. Therefore, the correlated models are then extended to develop 60 DESs consisting of 15 choline chloride DESs, 4 different hydrophilic DESs, 17 tetraalkylammonium organic salt origin DESs, 7 menthol DESs, and 17 thymol-based DESs.

Insights on the Cellulose Pretreatment at Room Temperature by Choline-Chloride-Based Deep Eutectic Solvents: An Atomistic Study

“…From Table 3, the behavior of the 𝑂𝐶 − 𝐻𝑂 HB becomes stronger in the following order: ChCl/oxalic acid < ChCl/ethylene glycol < ChCl/levulinic acid, because its corresponding distance decreases as 2.01 > 1.95 > 1.81 𝐴 . These behavior agrees with the corresponding Kamlet-Taft β values (0.27, 0.57, and 0.61, respectively), and Kamlet-Taft α values (1.19, 1.47, and 1.55) (Kundu et al 2020).…”

“…S7f). The shortest 𝑂𝐷 − 𝐻𝑂 distance was found for the cellulose-ChCl/levulinic acid system, in agreement with its larger Kamlet-Taft α parameter (1.55 (Kundu et al 2020)). Finally, from the RDFs analysis, the HBs involving the OD and the HG atoms in ChCl/ethylene glycol (Fig.…”

“…It is important to note that, to our knowledge, it was not found a complete set of experimental data for the β and α parameters for the evaluated DESs in this work (Ren et al 2016;Florindo et al 2018). For this reason, the predicted Kamlet-Taft parameters values from ab-initio calculations by Kundu et al (2020), were included. From Häkkinen and Abbott (2019) indicated that the dissolution of cellulose is favored in some ILs due to their crystalline structure, since the addition of cellulose produces an increase in the entropy of the system.…”

“…This ability to form stronger hydrogen bonds of the HBD towards the OD atoms, i.e. the hydrogen bond acidity capacity, measured through the Kamlet-Taft α parameter (Dwamena and Raynie 2020;Kundu et al 2020), could be explained from the interactions between 𝐶𝑙 and the HO atoms (Fig. S7b, S7d, S7f, and S7h).…”

“…In the present work, the choline-chloride (ChCl) was selected as HBA, due to its large biodegradability, high biocompatibility, low toxicity, low cost, and biomass-origin (Halder and Cordeiro 2019;Körner et al 2019;Zhang et al 2020). Consequently, we have selected the ChCl/ethylene glycol (molar ratio 1:2), ChCl/oxalic acid (1:1), ChCl/urea (1:2), and the ChCl/levulinic acid (1:2) DESs due to their broad range of both viscosity (which spans from 41 cP to ~7600 cP) (D'Agostino et al 2011;Florindo et al 2014;Xie et al 2014;Yadav and Pandey 2014;Chemat et al 2016;Harifi-Mood and Buchner 2017;Shekaari et al 2017) and hydrogen bond basicity (from ~0.3 to ~0.6) (Florindo et al 2018;Kundu et al 2020). Furthermore, the observed properties have been related with the capability of DESs to dissolve cellulose (Ren et al 2016).…”