Purification and Kinetics of Chlorogenic Acid from Eucommia ulmoides Oliver Leaves by Macroporous Resins Combined with First-principles Calculation

Background: A simple and effective method to separate chlorogenic acid from Eucommia ulmoides leaves with macroporous resin was studied in this paper. Methods: In order to optimize the separation process of chlorogenic acid from Eucommia ulmoides leaves, dynamic adsorption and desorption experiments were carried out on a glass column filled with XDA-8 resin. Based on the First-principles calculation, the possible adsorption models were simulated. Results: Among the six macroporous resins, XDA-8 showed good adsorption/desorption capacity and a high adsorption/desorption ratio for chlorogenic acid. After being treated with XDA-8 resin once, the content of chlorogenic acid from the extraction increased by 525%, and the recovery of chlorogenic acid reached 85.36%. Conclusion: At 25°C, the adsorption behavior of chlorogenic acid on XDA-8 resin was consistent with the Langmuir isotherm model and pseudo-second-order kinetic model. Furthermore, by calculating the charge changes of the O atom at each position in the chlorogenic acid molecule and the H atom at the adsorption site in polystyrene molecule with resin skeleton, and combining with the electron cloud density distribution diagram of chlorogenic acid and resin skeleton, the adsorption of chlorogenic acid by XDA-8 resin is mainly due to the charge transfer, which causes the electron cloud to overlap.