Carbon-Based Solid Acid for Efficient and Clean Production of Diosgenin From Biomass by Alcoholysis

Abstract

A new solid acid catalyst was prepared from the residue of the diosgenin production process by activation, carbonization, and sulfonation, and the carbonization product exhibited bigger surface area than most of the activated carbon from biomass. The carbon-based solid acid was used in the production of diosgenin from saponins in ginger by alcoholysis. The optimum conditions for both the synthesis of carbon-based solid acids and alcoholysis conditions were investigated. The optimum yield of diosgenin can be obtained, which was 17.89%, 45% higher than that of conventional sulfuric acid hydrolysis. The acid can be reused five times and showed better stability and less activity loss compared with other solid acids. The solid acid could be recycled at least five times and still maintain the original extraction rate. Finally, based on the analysis of the data obtained by liquid chromatography–mass spectrometer, we deduced the possible pathway and mechanism of the alcoholysis of diosgenin, which also showed another aspect of the successful extraction of diosgenin from saponins by solid acid through the synergistic effect of hydrolysis and alcoholysis.