O-Isobutyl-N-hydroxyethyl Thionocarbamate: Molecular Behavior and Flotation Mechanism to Chalcopyrite

Herein, a chelating collector, O-isobutyl-N-hydroxyethyl thionocarbamate (IBHETC), was synthesized by using a safe ethanolamine instead of volatile gas ethylamine, and its molecular behavior and flotation performance for chalcopyrite were carefully investigated. Nuclear magnetic resonance (NMR) (1D and 2D), molecular dynamics (MD) simulations, and density functional theory (DFT) calculations revealed the existence of two isomers similar to cis–trans isomers in IBHETC, owing to the planar nature of the C(═S)–N structure in the thionocarbamate group. It was further demonstrated that both isomers undergo the deprotonation–isomerization mechanism after reacting with Cu+, resulting in the formation of an identical IBHETC–(N,O,S)–Cu complex through N, O, and S atoms. The surface tension test, Fourier transform infrared (FTIR), ultraviolet (UV), and X-ray photoelectron spectroscopy (XPS) results revealed that IBHETC selectively adsorbs onto the surface of chalcopyrite to realize hydrophobic flotation through the synergistic behavior of hydroxyl and thionocarbamate groups. This research is expected to promote the molecular design and industrial applications of functional surfactants.