Quantum Chemistry Insight into the Interactions Between Deep Eutectic Solvents and SO2.

Mert Atilhan,Tausif Altamash,Santiago Aparicio

doi:10.3390/molecules24162963

Abstract

A systematic research work on the rational design of task specific Deep Eutectic Solvents (DES) has been carried out via density functional theory (DFT) in order to increase knowledge on the key interaction parameters related to efficient SO2 capture by DES at a molecular level. A total of 11 different DES structures, for which high SO2 affinity and solubility is expected, have been selected in this work. SO2 interactions in selected DES were investigated in detail through DFT simulations and this work has generated a valuable set of information about required factors at the molecular level to provide high SO2 solubility in DES, which is crucial for enhancing the current efficiency of the SO2 capture process and replacing the current state of the art with environmentally friendly solvents and eventually implementing these materials in the chemical industry. Results that were obtained from DFT calculations were used to deduce the details of the type and the intensity of the interaction between DES and SO2 molecules at various interaction sites as well as to quantify short-range interactions by using various methods such as quantum theory of atoms in a molecule (QTAIM), electrostatic potentials (ESP) and reduced density gradients (RDG). Systematic research on the molecular interaction characterization between DES structures and SO2 molecule increases our knowledge on the rational design of task-specific DES.

Highlights

Sustaining air quality at desirable levels requires the constant management and control of greenhouse gases [1]
density of states (DOS) analysis can be used to decipher the nature of the charge transfer that occurs between the various active sites of the Deep Eutectic Solvents (DES) and SO2 molecules
A thorough density functional theory (DFT) analysis has been conducted on 9 different selected DES compounds on their affinity towards SO2, as they are being considered as an alternative solvents for industrial purposes

Summary

Introduction

Sustaining air quality at desirable levels requires the constant management and control of greenhouse gases [1]. These gases have a severe impact on the environment and bring about its own ecological problems as industries continue to emit toxic greenhouse gases, which have reached unprecedented levels lately [2]. Direct GHGs have long atmospheric lifetimes and they have a high cumulative radiative-forcing effect. As an indirect GHG, SO2 has a short atmospheric lifetime and a lack of radiative-forcing effect, it has a relatively lower global warming effect over time. Despite being an indirect GHG and having a low concentration, SO2 could be extremely dangerous and hazardous to the environment as well as human health when released to Molecules 2019, 24, 2963; doi:10.3390/molecules24162963 www.mdpi.com/journal/molecules

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