New chloroacetic acid-based deep eutectic solvents for solubilizing metal oxides

• Chloroacetic acidl was paired with four HBAs to form new DESs. • TEAB, TPAB, TBAB, and TBAHS were used as HBA. • The physical characteristic of the prepared DESs were studied as a function of temperature. • The effect of alkyl chain and temperature on the DESs physical properties was studied. • The DESs mixture was applied for metal oxide solubilizes. In this work, new chloroacetic acid-based deep eutectic solvents (DESs) were prepared from the tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, and tetrabutylammonium hydrogen sulfate as a hydrogen bond acceptors (HBAs) in combination with chloroacetic acid as a hydrogen bond donor (HBD). The prepared deep eutectic solvents were characterized by measuring their physical properties such as density, sound velocity, electrical conductivity, viscosity, refractive index, and surface tension with the variation of temperature. The new deep eutectic solvent was applied for solubilizing Fe 3 O 4 , CuO, ZnO, and PbO metal oxides. The obtained solubilizing data was compared with the other deep eutectic solvent based on the different hydrogen bond donors and acceptors which were used for the solubility of metal oxides.