Screening Physical Solvents for Methyl Mercaptan Absorption Using Quantum Chemical Calculation Coupled with...

Area of Science:

• Computational Chemistry
• Chemical Engineering
• Environmental Science

Background:

• Methyl mercaptan (MeSH) is a toxic gas requiring efficient removal from industrial emissions.
• Physical solvents are explored as an alternative to chemical absorption for MeSH removal.
• Accurate prediction of solvent performance is crucial for developing effective MeSH abatement technologies.

Purpose of the Study:

• To develop and validate a quantum chemical screening method for identifying high-performance physical solvents for MeSH absorption.
• To analyze the absorption solubility and thermodynamic behavior of five candidate solvents for MeSH.
• To elucidate the underlying mechanisms governing MeSH absorption in physical solvents.

Main Methods:

• Utilized the COSMO-RS model to calculate absorption solubility and thermodynamic properties of five solvents (DMSO, SUL, PC, DMF, NMP) for MeSH.
• Employed Quantum Theory of Atoms in Molecules (QTAIM) and Reduced Density Gradient (RDG) to investigate the absorption mechanism.
• Validated computational results by comparing calculated Henry coefficients with experimental data.

Main Results:

• The predicted solubility order for MeSH absorption was NMP > PC > DMSO > SUL > DMF.
• Van der Waals forces and hydrogen bonding were identified as key factors influencing MeSH solubility.
• Experimental Henry coefficients confirmed the predicted solubility trend, though quantitative deviations were observed.

Conclusions:

• The COSMO-RS model combined with QTAIM and RDG provides a feasible approach for the qualitative screening of physical solvents for MeSH removal.
• N-methyl-2-pyrrolidinone (NMP) emerged as a promising solvent candidate for MeSH absorption.
• Further refinement of computational methods is needed for accurate quantitative prediction of Henry coefficients.