Abstract: In this paper, the effects of reaction temperature, reaction time and the amount of potassium ethanolate as catalyst on the purity and yield of conjugated linoleic acid ethyl ester (CLAEE) prepared from safflower seed oil ethyl ester were investigated. The main physicochemical indicators, fatty acid composition, and structure of CLAEE were determined. CLAEE meeting the market requirements was prepared under the following optimized conditions: reaction temperature 110 ℃, catalyst amount 5% (m/m), reaction time 3 h, vacuum degree ?0.1 MPa, and rotation speed 60 r/min. The content of active conjugated linoleic acid ethyl ester in the product was (75.44 ± 1.18)%, and the content of double trans conjugated linoleic acid ethyl ester was (0.24 ± 0.09)%. The yield of the product was (69.50 ± 3.09)%. The total yield of CLAEE and conjugated linoleic acid was 90%. The structure of the CLAEE product was characterized by infrared spectroscopy (IR), UV absorption spectroscopy, gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR). It was verified to contain four isomers, namely c9,t11-CLAEE, t10,c12-CLAEE, t9,t11-CLAEE and t10,t12-CLAEE, the main ones being active conjugated ethyl linoleate, namely c9,t11-CLAEE and t10,c12-CLAEE.

Key words: conjugated linoleic acid ethyl ester, safflower seed oil ethyl ester, potassium ethoxide, structural characterization