IntroductionPolicosanols are a kind of primary aliphatic long-chain alcohol with chain lengths varying from 24 to 34 carbons, and octacosanol is one of the major components of policosanols with 28 carbons [1,2]. The most common sources of policosanols are sugar cane, bees wax, wheat germ, rice bran, sorghum kernel and sunflower seed [3][4][5]. Policosanols are also found in the leaves, fruits, nuts, and seeds of many foods [6].In recent years, policosanols have attracted much attention due to their potential beneficial effects for human health. Policosanols provided various physiological effects in the prevention or treatment of cardiovascular diseases and dermatological diseases [7,8]. Policosanols acted as a cholesterol-lowering agent by inhibiting endogenous cholesterol biosynthesis and enhancing low density lipoprotein (LDL) catabolism [7]. Daily intake of 5-20 mg policosanols decreased the LDL level by 19-31 % and total cholesterol (TC) concentration by 13-23 %, increased high density lipoprotein (HDL) cholesterol level in the range of 8-29 % [9, 10]. Daily supplement of 40 mg policosanol was also found to be effective in lowering the serum triglyceride concentration [9]. Moreover, previous studies reported that policosanols decreased endothelial damage, platelet aggregation and the development of foam cells [7,11]. Octacosanol was considered to be the major active policosanols responsible for efficacy since it was present in the largest quantity [6,12]. Octacosanol improved oxygen usage by strengthening the heart, keeping low LDL and high HDL levels, thereby maintaining healthy heart function [9,13].Currently, policosanols including octacosanol are mainly produced by saponification of a by-product from the dewaxing process. And policosanols are commercially Abstract Octacosanol, as the major active policosanol, has attracted much attention due to the potential beneficial effects for human health. However, free octacosanol has a high melting point, poor oil solubility and low bioavailability, which greatly restricts its practical application. In this study, we report a highly efficient method for an ionic liquids (IL)-catalyzed synthesis of octacosanol ester by direct esterification with linoleic acid. The synthesized product was purified, subsequently characterized by FT-IR, MS and NMR and finally confirmed to be octacosanol linoleate. The reaction parameters were investigated and the conversion reached 91.3 ± 4.8 % under the optimum conditions: IL 1-butylsulfonate-3-methylimidazolium hydrogen sulfate ([BSO 3 HMim][HSO 4 ]) as catalyst, IL dose 1.5 % (related to the mass of both reactants), 1:1 molar ratio of octacosanol to linoleic acid, 80 °C, and 1 h. The melting point and oil solubility of octacosanol were greatly improved by esterification with linoleic acid, facilitating the incorporation into a variety of oil-based systems.