Effect of phospholipid structure on kinetics and chemistry of soybean oil hydrogenation with nickel catalysts

Abstract

Phospholipids (PL) are one of the compounds which poison nickel catalysts during the hydrogenation process. It was affirmed that even trace amounts of PL (5—10 ppm P) cause a decrease in catalyst activity. Quantities over 50 ppm P almost totally inhibit the reaction. In bleached oils used for hydrogenation, PL exist as native compounds as well as products of their transformation. In the present work, the effect of native phospholipids, lysophospholipids (LPL) and phosphatidic acids (PA) on the kinetics and chemistry of soybean oil hydrogenation was investigated. It was found that PA were more toxic to nickel catalysts than LPL and native PL. Fine-grained catalyst was more active and resistant to the poisoning effect of phospholipids than moderate-grained catalyst. No changes in the oil hydrogenation chemistry were observed in the presence or absence of PL; thus, linoleic and linolenic selectivity and specific isomerization did not undergo any change.