超临界CO_2氢化大豆油工艺优化及动力学分析

以自制Ni-Ag/SBA-15为催化剂,在超临界CO_2条件下对氢化大豆油的工艺进行研究,其最佳工艺条件为CO_2压力8.0 MPa、氢气分压3.40 MPa、氢化温度100℃、催化剂用量0.20%、搅拌速率300 r/min、氢化时间90 min,产品碘值为86.0 g I_2/100 g,反式脂肪酸(trans fatty acids,TFAs)含量为11.7%;利用氢化动力学方程,运用MATLAB软件编辑运算程序,研究超临界CO_2氢化大豆油的反应速率与选择性,与常规状态下氢化进行比较,发现超临界CO_2状态氢化反应速率较快,且对亚麻酸及亚油酸有更好的氢化选择性。同时,在超临界CO_2条件下进行氢化,氢化大豆油产品中的TFAs和硬脂酸含量更低,分别为11.7%和9.4%。

Optimization and Kinetics of Hydrogenation of Soybean Oil in Supercritical CO2

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.