Polymer-based solid acid catalyst for the green production of diosgenin

In this study, a novel polymer-based solid acid catalyst was prepared by free radical polymerization of N, N′-methylenebisacrylamide (MBA) and allyl sodium sulfonate (SAS), followed by acidifying of diluted hydrochloric acid. The prepared solid acid was fully characterized by FTIR, solid-state 13 C-NMR, TGA, XPS, element analysis, and SEM. In addition, the prepared solid acid poly(MBA-SAA) was used as a catalyst to extract diosgenin from Dioscorea zingiberensis C.H.Wright (DZW) under solvethermal condition using ethanol as a solvent. And the optimal conditions of temperature (104.02°C), alcoholysis time (5.87 h) and solid acid dosage (0.39 g), were obtained by response surface analysis based on the results of single factor experiments. The yield of diosgenin (14.53%) obtained in the alcoholysis is higher than that of the traditional sulfuric acid hydrolysis method. The alcoholysis products were analyzed by high performance liquid chromatography-mass spectrometry (LC–MS) and UV–vis, respectively. The results showed that the solid acid with higher catalytic activity and good reusability can replace sulfuric acid to extract diosgenin, which has a great potential for the clean production of diosgenin in industry.