The relationship between swelling and hydrolysis of Trichosanthin (TCS) in aqueous ionic liquids

•It was first time to study the swelling behaviour of Trichosanthin.•Damage extent to Trichosanthin’s structure depended on the acidity of ionic liquids.•The equilibrium absorbency showed the same tendency with the acidity order.•The relationship between swelling and hydrolysis was competitive inhibition.

The swelling of Trichosanthin (TCS) particles in aqueous ionic liquids (ILs) was observed to discover the mass transfer mechanisms in natural products-solvent system. The hydrolysis behaviour of TCS accompanied with swelling was investigated to explore the balance of the two processes. The results of Colour Electron Microscopy (CEM), scanning electron microscope (SEM), thermo gravimetric analysis (TGA) and Fourier Transform Infrared (FTIR) spectroscopy showed that swelling expended the internal structure with solvent permeation. While 2.5 mol/L [HMIM][HSO4] (10 ml) was employed, the equilibrium absorbency of TCS (60–80 mesh) could reach 1.85 at 80 °C. The IL was reused for 5 times, both the equilibrium absorbency and hydrolysis degree of TCS were approximately consistent. The hydrolysis degree would decrease sharply with the increase of equilibrium absorbency. In conclusion, the relationship between swelling and hydrolysis was competitive inhibition. This finding could be applied in related process of TCS and would lay the foundation of the further study in leaching balance.

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