Kinetics, Thermodynamics, and Solvent Polarity Effects of Ultrasound-Negative Pressure Cavitation Fractional Precipitation of (+)-Dihydromyricetin

In this study, the effect of precipitation solvent polarity during ultrasound-negative pressure cavitation methanol–water fractional precipitation was investigated to effectively purify (+)-dihydromyricetin from biomass. The optimal solvent conditions were selected by changing the solvent polarity and the precipitation temperature. Additionally, kinetic and thermodynamic analyses of the precipitation process were conducted. The highest yield (96.87%) and purity (92.35%) of (+)-dihydromyricetin were obtained at a polarity index of 9.51. Furthermore, the diffusion coefficient and rate constant reached maximum values of \(8.89\times {10}^{-10} {\text{cm}}^{2}/\text{s}\) and 0.85, respectively. Impurities in the sample were selectively removed via the polarity of the precipitation solvent. The thermodynamic parameters revealed that the precipitation was exothermic, irreversible, and non-spontaneous.