Ultrasound-assisted deep eutectic solvent/petroleum ether biphase system for the green and efficient production of diosgenin

Abstract

Diosgenin, as an important precursor of steroid hormone drugs, is distributed in the root of Dioscorea Zingiberensis C. H. Wright (DZW) in the form of its sugar ligand-dioscin. The traditional production method of diosgenin is using sulfuric acid to hydrolyze the DZW, during the hydrolysis process, all components of the raw materials are degraded, resulting in a large amount of acid-containing wastewater with high Chemical Oxygen Demand (COD) values, causing serious pollution of the environment. In this paper, we proposed a biphase system composed of B acid type deep eutectic solvent (DES) and petroleum ether which can combine the extraction and hydrolysis of dioscin, and the purification of diosgenin into one step. The yield of diosgenin obtained by this method can reach 99.5% of that of the traditional method, while the COD value in the wastewater are less than 1% of the traditional method. The results showed that the best composition of DES is benzyltrimethylammonium chloride and oxalic acid, and the optimized parameters were material-to-liquid ratio 1:6 (w/v), ultrasonic power 200W, temperature 40 °C, ultrasonic time 15min and DES/petroleum ether ratio 1:6(w/v). After repeated use of the bi-phase system for 6 times, the production efficiency of diosgenin can still reach more than 95%, and the COD value of wastewater were stable. Furthermore, in order to better understand the advantages of this method, this method was compared with several other diosgenin production methods. In summary, the DES/petroleum ether biphase system proposed in this paper is an efficient and cleaner production method of diosgenin.

Keywords

• DES/Petroleum ether biphase system
• Dioscin
• Diosgenin
• COD