Monitoring of hydrogenation with various catalyst ratios

Soybean oil was hydrogenated using two different nickel‐based commercial catalysts (Nysosel 222 and SP‐10) at various ratios in 4‐L reactors under constant conditions (165°C, 2 bar hydrogen pressure, and 500 rpm stirring rate). Trans isomer formation, reaction rates, selectivity ( S ) ratios, and melting behaviors of the samples were monitored during the reactions. When Nysosel 222 was used at 0.02, 0.03, and 0.04%, iodine values (IV) were reduced from 130.1 to 70.6, 50.9, and 44.7 and total trans isomers increased from 0 to 34.2, 43.3, and 40.5%, respectively, after 100 min of hydrogenation. However, SP‐10 reduced IV from 130.1 to 77.2, 75.7, and 71.3 after 100 min when used at 0.1, 0.15, and 0.2%, respectively, whereas total trans isomers were 58.6, 70.4, and 70.7%. Reaction rates increased with catalyst ratio and time but were higher for Nysosel 222 than for SP‐10 although 5–10 times less Nyosel 22 was used than SP‐10. Linoleate selectivity ( S 32 ) was almost constant for Nysosel 222, whereas it was higher but fell with time for SP‐10. Increasing the catalyst ratio decreased the time needed to reach the highest oleate selectivity ( S 21 ) ratios, and the IV values where the highest S 21 were attained were different for the catalysts. Increases in m.p. of SP‐10 samples were slower after IV values of 80 were attained, where S 21 ratios reached to higher values. Solid fat contents (SFC) of these samples fell markedly above 21.1°C, and steeped SFC curves were obtained.