Revealing the Structure-Interaction-Dissolubility Relationships through Computational Investigation Coupled with Solubility Measurement: Toward Solvent Design for Organosulfide Capture

Understanding the complex relationships among molecular structures, weak solute-solvent interactions, and dissolving affinity is fundamentally important to successfully identify potential solvents from a large chemical space for diverse absorption capture and separation. In this study, a series of compounds including alkanolamines, amines with cyclic substituents, etheramines, polyamines, sulfonamides, and several commercial physical absorption solvents were selected and methyl mercaptan (MeSH) was used as a model organosulfide for both the quantum chemistry calculation and solubility measurement. The weak intermolecular interactions within different solvent-solute systems were examined by using reduced density gradient and quantum theory of atoms in molecules analyses. The relationship between the structural characteristics of the solvents and their interactions with MeSH was revealed, and the intermolecular interaction is correlated to the dissolubility of MeSH-insolvent. Rules for designing molecules were proposed and used to guide the generation of a potential solvent with enhanced dissolving affinity to MeSH, 1-(2-(diethylamino)ethoxy)butan-2-amine. It is indicated that the designed compound has stronger intermolecular interaction with MeSH as compared to the screened solvent candidate. The present study enables efficient molecular exploration and design of solvent candidates for absorption capture of diverse environmental unfriendly compounds as well as wide separation applications based on selective dissolving.