Abstract: In order to reduce the production of trans-fatty acids during oil hydrogenation, Pd/carbon nanotubes (Pd/CNTs) were used as a catalyst for the transfer hydrogenation of soybean oil. Response surface methodology was used to optimize the reaction conditions based on the iodine value of soybean oil, and the kinetics of the hydrogenation reaction was analyzed. The results showed that the optimum reaction conditions were as follows: hydrogenation temperature 84 ℃, catalyst dosage 0.2%, ammonium formate donor concentration 0.33 mol/50 mL, and hydrogenation time 90 min. The reaction rate constants for trienoic acid, dienoic acid and monoenoic acid were 4.9 × 10-2, 8.7 × 10-3 and 8.31 × 10-4, respectively. The selectivity for hydriding linoleic acid and linoleic acid was as high as 5.63 and 10.47. The iodine value of hydrogenated soybean oil, containing only 10.2% trans-fatty acids, was 95.3 g/100 g. Catalytic transfer hydrogenation has great prospects for application in the preparation of low-trans-fatty-acid hydrogenated oils and can provide a theoretical basis for the development of the oil hydrogenated oil industry.

Key words: Pd/carbon nanotubes; catalytic transfer hydrogenation; soybean oil; trans-fatty acids; selectivity