Effect of cationic structure of ionic liquids on dissolution and regeneration of white hide powder

3-methyl-1-ethoxycarbonylimidazolium chloride ([EtMIM]Cl), was synthesized for white hide powder dissolution. White hide powder was successfully dissolved in [EtMIM]Cl, and regenerated from methanol. The dissolution data and thermodynamic parameter of white hide powder in [EtMIM]Cl and [BMIM]Cl were studied. Hydrogen bond basicity (β) and general polarizability (π*) of ILs were determined. The white hide powders were characterized by FT-IR, XRD, and TGA. The results showed that the maximum solubility of white hide powder in [EtMIM]Cl was higher than that in [BMIM]Cl at same dissolution temperature. At same temperature and same solid content, the dissolution time of white hide powder in [EtMIM]Cl was shorter than that in [BMIM]Cl. Density functional theory (DFT) simulation showed that two kinds of hydrogen bonds (C-H/O and C-H/Cl) and eight strong hydrogen bonds are found in [EtMIM]Cl/GPH, while seven hydrogen bonds are found in [BMIM]Cl/GPH. The carboxylic acid ester cationic group in [EtMIM]⁺ has more electronegative ester groups and stronger electronic cloud density oxygen atoms than alkyl group in [BMIM]⁺, [EtMIM]Cl is easier to destroy the intermolecular or intramolecular hydrogen bonds in white hide powder, so as to accelerate the dissolution of white hide powder in [EtMIM]Cl. The molecular simulation results indicated that both Cl⁻ anions and [EtMIM]⁺ cation played important roles in the white hide powder dissolution.