Multi-objective optimization and extraction mechanism understanding of ionic liquid assisted in extracting essential oil from Forsythiae fructus

Presently, the essential oils are obtained by hydro-distillation, which demand long extracting time and great energy. Consequently, efficiently obtaining essential oils needs to be considered. In this work, microwave-assisted ionic liquids treatment followed by hydro-distillation (MILT-HD) is used to extract essential oils. The purpose is to use the multivariate analysis model to investigate the effects of process parameters on extraction efficiency and explore the mechanism for enhancing extraction yields. Through multi-objective optimization, optimum parameters are ionic liquid ratio of 70.00%, irradiation time of 6.00 min and irradiation power of 30.00%. Under these conditions, MILT-HD can significantly increase the extraction efficiency. And it can reduce energy demands. Furthermore, the mechanism for efficient extraction is innovatively explored by electrostatic potential analysis and temperature profile. The ionic liquid has a strong interaction with cellulose, and can better absorb microwave energy and quickly convert it into heat. Under the synergistic interactions of ionic liquids-cell wall and ionic liquids-microwave, the MILT-HD can strongly destroy the cell wall structure. It makes the essential oil efficiently diffuse. Based on this work, it provided a way to obtain Forsythiae fructus essential oils efficiently. And It is helpful to improve the comprehensive understanding of the extraction process of MITL-HD.