DFT-based study on the molecular interaction of hydrochloric acid with different extractants

•The binding force of different extractants to HCl was investigated by Density functional theory (DFT).•DFT can describe the interaction of the extractant with HCl and predict the structure of the resulting complex.•The calculation results show that amine TEHA has unique advantages for extracting HCl.•The accuracy of the DFT calculation is verified by experiments.•DFT can serve as an effective tool for studying extraction mechanisms.