摘要
Electrochemical hydrogenation is a novel, alternative process for selective hydrogenation of vegetable oils, because of its high extent of hydrogenation and low trans-isomer formation. Electrochemical hydrogenation of soybean oil in a diaphragm reactor with a formate ion concentration of 0.4 mol/l at pH 5.0 under moderate temperature conditions using a current density of 10 mA/cm 2 was investigated to identify the critical conditions affecting the selective hydrogenation reaction and the resulting fatty acid profile. The optimum composition was an oil-to-formate solution ratio of 0.3 (w/w), 2-3 g EDDAB in 100 g soybean oil, and 0.8% Pd-C catalyst loading. The electrochemical hydrogenation reaction of soybean oil was described by first-order kinetics, and the kinetic rate constants and reaction selectivity were determined accordingly. Re-use of the Pd-C catalyst up to five times was found to be acceptable. A comprehensive evaluation revealed that the most significant conditions affecting the extent of hydrogenation and the trans fatty acids content of final products were operating temperature, pH of the formate solution, and catalyst loading. © 2010 AOCS.