Abstract: In this paper, Ni-Ag/SBA-15 catalyst was used to catalyze the hydrogenation of soybean oil in supercritical CO2. The optimum conditions were determined as follows: CO2 pressure, 8.0 MPa; hydrogen partial pressure, 3.40 MPa; hydrogenation temperature, 100 ℃; the amount of catalyst, 0.20%; stirring speed, 300 r/min, and hydrogenation time, 90 min, giving a product with an iodine value of 86.0 g I2/100 g, and a trans fatty acid (TFA) content of 11.7%. Using hydrogenation kinetic equation and MATLAB software program, the reaction rate and selectivity for supercritical CO2 hydrogenation of soybean oil were investigated. Compared with conventional hydrogenation, the hydrogenation rate in supercritical CO2 was higher, and the hydrogenation selectivity for linolenic acid and linoleic acid were better. At the same time, the TFA and stearic acid contents of hydrogenated soybean oil products were 11.7% and 9.4% in supercritical CO2, which were lower than that from conventional hydrogenation.

Key words: Ni-Ag/SBA-15, supercritical CO2, hydrogenated soybean oil, kinetics, reaction rate constant