Separation Of Isomeric Ursolic Acid And Oleanolic Acid In Conventional Solvents And Ionic Liquids

Ursenoic acid(UA)and Oleanolic acid(OA)are a pair of isomers that are widely found in plants,herbs,and foods,all belonging to pentacyclic triterpenoic acids.All of them have important pharmacological properties and are widely used in clinical applications.People have studied UA and OA earlier.With the deepening of pharmacological activities,they have attracted more and more attention because they are isomeric.As the properties are very close,it is very difficult to separate them.Therefore,the separation of the two has become a research hotspot and a difficult point in recent years.In this dissertation,crystal separation technology was applied to the purification and separation of natural isomers.1.Measured UA and OA at different concentrations of isopropanol(25%,35%,45%,55%,65%,75%),Solvent(ethanol + water + sodium hydroxide)in different ethanol concentrations(25%,35%,45%,55%,65%,75%)and different solvents(Mixed solution of 1-ethyl-3-methylimidazolium trifluoromethanesulfonimide salt and ethanol with 5% by mass of ionic liquid,5% 1-octyl-3-methylimidazolium tetrafluoroborate solution Mixed solution with ethanol,5% mixed solution of 1-butyl-3-methylimidazolium tetrafluoroborate and ethanol,5% of 1-butyl-3-methylimidazolium bistrifluoromethanesulfonimide salt and ethanol Mixed solution,mixed solution of 5% 1-octyl-3-methylimidazolium trifluoromethanesulfonimide salt and ethanol,mixed solution of 5% 1-octyl-3-methylimidazolium hexafluorophosphate and ethanol).Solubility Solubility Solubility of ursolic acid and oleanolic acid in 75% isopropyl alcohol,The mass fraction is 75% ethanol and in 5% 1-octyl-3-methylimidazolium hexafluorophosphate mixed solution The difference is relatively large.2.According to the different solubility of ursolic acid and oleanolic acid in isopropanol and ionic liquids,the crystals were separated by crystallization.It was explored that crystallization of ursolic acid and oleanolic acid in organic solvents was best.The process is 75% isopropanol,the crystallization time is 14 h,the crystallization temperature is 30°C,and the mass ratio of ursolic acid to oleanolic acid is 1.At this time,the crystalline mass fraction of oleanolic acid can reach over 80%.The best separation process for crystallization in ionic liquids is: 5%1-octyl-3-methylimidazolium hexafluorophosphate,ursolic acid and oleanolic acid charge ratio of 1.5,the crystallization temperature is 30 °C,Crystallization time is 14 h.At this point,the crystalline mass of oleanolic acid can reach about 85%.