电化学氢化法制备低反式脂肪酸大豆油脂

Produce of Low Trans Fatty Acids Soybean Oil by Electrochemical Hydrogenation in a Diaphragm Reactor

摘要:

设计了质子转移膜式电化学氢化反应器，在低温（30~75 ℃）、常压和低电流密度下实施大豆油氢化反应，反应以稀甲酸钠溶液作为介质，通过电化学方法使甲酸根离子再生并作为电化学氢化反应媒质。考察电化学氢化反应条件反应温度、机械搅拌强度、EDDAB量和溶液组成对氢化油脂脂肪酸组成、碘值、反式脂肪酸含量、异构化指数和氢化反应选择性的影响。结果表明，质子转移膜式电化学氢化法制备氢化大豆油的最适工艺参数为反应温度60 ℃，机械搅拌强度850 r/min，3.0 g EDDAB /100 g油，溶液组成0.3 g/g，在此条件下获得碘值为82.73 g I2/100 g油，TFAs含量为13.3%，酸值为0.15 mg KOH/g油，过氧化值为0.070 g/100 g油的氢化大豆油产品。与传统气体氢化工艺相比，当完成相同程度氢化时，质子转移膜式电化学氢化可使反式脂肪酸含量减少71％。

Abstract:

The proton transfer membrane electrochemical hydrogenation reaction system was designed for soybean oil to hydrogenate under moderate processing temperature, atmospheric pressure and low current density. The formate ion was regenerated at the cathode and acted as a mediator during the hydrogenation process. The effect of various processing parameters such as temperature, agitation speed, the amount of EDDAB and the oil-water ratio on the fatty acid profile, iodine value, trans fatty acid content, the specific trans isomerization index and hydrogenation selectivity were investigated. The optimum technological parameters of hydrogenation were as follows: the reaction temperature 60 ℃, speed of agitation 850 r/min, the content of EDDAB 3 g in 100 g soybean oil and the oil-water ratio 0.3 g/g. Under the optimal technical conditions, the hydrogenated soybean oil was obtained, which contained 13.3% TFAs, IV of 82.73 g I2/100 g oil, AV of 0.15 mg KOH/g oil and PV of 0.070 g/100 g oil. Compared to the traditional hydrogenation process, the application of the diaphragm electrochemical hydrogenation technique resulted in up to 71% reduction in trans fatty acid when the same level of hydrogenation was accomplished.