Combined Experimental and Theoretical Study on High Pressure Methane Solubility in Natural Deep Eutectic Solvents

Abstract

In this paper, we report high pressure experimental measurements and detailed density functional theory (DFT) as well as molecular dynamic (MD) simulations of methane (CH 4 ) solubility in natural deep eutectic solvents (NADESs) that were prepared by using alanine (Al), betaine (Be), and choline chloride (ChCl) used as hydrogen bond acceptors (HBA) and lactic acid (La), malic acid (Ma), and phenylacetic acid (Paa) used as hydrogen bond donors (HBD). Experiments were performed on Al:La, Be:La, ChCl:La, ChCl:Ma, and ChCl:Paa systems up to 50 bar at 298.15 K. Meanwhile, this work includes the quantum theory of atoms in molecules (QTAIM) calculations that allow quantifying and characterizing the short-range interactions of studied systems, which is reported for the first time for NADESs and CH 4 interactions. Furthermore, MD simulations shed light onto the characteristics of intermolecular forces, particularly for hydrogen bonding, molecular arrangements in the liquid phases, and their role in fluid's properties. The presented results showed that the studied NADESs can be used for selective CO 2 /CH 4 separation in gas processing applications.

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

“…Most stable configurations for HBA and HBD were acquired from the PubChem ® database [71] and were optimized with the theory level that is mentioned in the previous section. This theory level has been selected based on our recent studies [72,73], which was proven for such DES and natural-DES (NADES) systems. The configurations for the HBA-HBD structure are based on the most stable configuration of the studies systems.…”

Effect of Hydrogen Bond Donors and Acceptors on CO2 Absorption by Deep Eutectic Solvents

“…In our previous work, we studied gas absorption performances via novel NADES, which was obtained by considering choline chloride (ChCl), alanine (Al), and betaine (Be) as HBA, and lactic acid (La), malic acid (Ma), and phenylacetic acid (Paa) as HBD. We showed that these NADES perform very well for CO 2 capture, especially at moderate pressures up to 50 bars, and between 298.15 K and 323.15 K isotherms [49][50][51]. CO 2 sorption experiments showed maximum absorption performance between 3.5 and 5 mmol CO 2 /gr of NADES in these experiments at the highest pressures.…”

“…Once the DFT simulations were obtained and the interactions energies were corrected for the BSSE [59], the cases that gave the highest interaction energies were considered for further DFT analysis. In this work B3LYP with the 6-311++G** theory level was selected, based on its accuracy and reasonable computational time [49,50]. The summary of interaction energies for the selected cases are provided in Table 3 in eV units.…”

Computer Simulations of Deep Eutectic Solvents: Challenges, Solutions, and Perspectives

“… No DES Method/Basis Topic of the Publication Reference 1 1-ethyl-3-methylimidazolium chloride: Imidazole Different molar ratios AIMD The BLYP functional with triple-ζ valence polarization basis set and GTH pseudopotentials. CP2K/QUICKSTEP code DFT B3LYP/6-311+G(2d,2p) DES as physical solvents for remarkable separation of H 2 S from CO 2 [ 409 ] 2 1,8-diazabicyclo [5.4.0]undec-7-enium: methylthiourea (4:1) DFT M06e2X/6-311++G(d,p) Dissolution of cellulose in DES [ 339 ] 3 24 choline chloride-based DES with molar ratio from 1:4 to 15:1 DFT B3LYP/6-311G(d,p) B3LYP/def2-SVP def2-SVP/J B3LYP/6-311G(d,p)/def2-TZVP def2-TZVP/J Biomass separation [ 119 ] 4 Alanine:Lactic Acid (1:1) Alanine:Malic Acid (1:1) Betaine:Lactic Acid (1:1) ChCl:Malic Acid (1:1) ChCl:Lactic Acid (1:1) ChCl:Fructose (1:1) DFT B3LYP/6-311++G(d,p) CO 2 absorption by DES [ 79 ] 5 Alanine:Lactic acid (1:1) Betaine:Lactic acid (1:1) ChCl:Lactic acid (1:1) ChCl:Malic acid (1:1) ChCl:Phenylacetic acid (1:2) DFT B3LYP/6-311++G(d,p) High Pressure Methane Solubility in Natural DES [ 410 ] …”