1997 年 3 巻 1 号 p. 10-16
A kinetic model including isomerization of fatty acids for soybean oil hydrogenation considering the adsorption of fatty acids on the catalyst surface affecting the hydrogenation rate has been evaluated in this study. The hydrogenation of soybean oil was conducted in a 12 l loop reactor equipped with a venturi nozzle. A reduced nickel catalyst was adopted. The hydrogenation experiment was carried out an experimental design with respect to reaction temperature, flow rate of catalyst-oil mixture, hydrogen pressure and reaction time. Adsorption of fatty acids including trans-acids on the surface of the reduced nickel catalyst significantly affected the reaction rate of the hydrogenation. The adsorption equilibrium coefficients of linolenic and linoleic acids were much greater than those of oleic and elaidic acids, which indicated that the former acids were hydrogenated faster than the latter acids. The time course of fatty acid concentration calculated from the hydrogenation rate constant derived from the kinetic model proposed in this study was in good agreement with those obtained from experiments. The kinetic model explained the hydrogenation totally with consideration of trans-acid formation.
