Interactions of Biodegradable Ionic Liquids with a Model Naphthenic Acid.

ABSTRACT: Density functional theory models are used to examine five biodegradable ionic liquids (ILs) each one consisting of a substitutional group (-OH, -NH_2, -COOH, -COOCH₃, and -OCH₃) incorporated into the cation of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF₄]). The results reveal that hydrogen atoms in -NH_2, -COOH, and -COOCH₃ form intramolecular hydrogen bonds with fluorine atoms in [BF₄]^-, whereas hydrogen atoms in -OH and -OCH₃ do not form hydrogen bonds with [BF₄]^-. Further analysis of electron density at bond critical points and noncovalent interactions suggest that [BMIM][BF₄] with -COOH has stronger intramolecular hydrogen bonds than other ILs. The extraction mechanism for a model naphthenic acid is hydrogen bonding, with F···H being the strongest hydrogen bond and O···H ranking second. More intermolecular hydrogen bonds occur when model naphthenic acid is adsorbed by [BMIM][BF₄] with -COOH and -COOCH₃. The interaction energy between model naphthenic acid and ILs with -COOH and -COOCH₃ is higher than that with -OH, -NH₂, and -OCH₃.

SUBMITTER: Wu C 

PROVIDER: S-EPMC5760565 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature