Separation of 1,8-Cineole and terpenes by Liquid-liquid extraction with green alkanediols

The difficulty of high purification of 1,8-cineole was mainly attributed to terpenes in plant essential oils. Therefore, the separation of 1,8-cineole and terpenes is significant for the preparation of high-purity 1,8-cineole. In this work, liquid–liquid extraction for high-purity 1,8-cineole was investigated with a series of low toxicity alkanediol extractants and some influence factors to the extraction were explored. 1,3-propanediol among alkanediols exhibited satisfactory purification effect on 1,8-cineole in model oil with high selectivity (7.02). Then, the back-extraction of 1,8-cineole and the extractant recovery were investigated with satisfactory results. Furthermore, the mechanism between the extractant and the target molecule in the extraction was studied by the molecular level through quantum computational chemistry. Finally, the whole liquid–liquid process was verified using real oil, Cinnamomum longepaniculatum oil , as raw material for considering its application and the high-purity of 1,8-cineole (98.3%) was achieved.