ARS | Publication request: APPLICATION OF HIGH PRESSURE LIQUID CHROMATOGRAPHY TO THE STUDY OF EDIBLE OIL HYDROGENATION

Submitted to: Association for the Advancement of Industrial Crops Conference
Publication Type: Abstract Only
Publication Acceptance Date: October 17, 1999
Publication Date: N/A

Technical Abstract: Soybean oil was hydrogenated in a stirred batch reactor at 120 C at pressures ranging from 50 to 500 psi. The iodine value (IV) was reduced from 130 to 80 and during the course of the reaction, samples of triglycerides were taken and analyzed by high pressure liquid chromatography (HPLC). Non hydrogenated soybean oil contains three triglycerides accounting for over 50% of the total triglycerides including trilinolein (LLL), dilinoleyl-olein (LLO), and dilinoleyl- palmitin (LLP). The HPLC data showed that the reaction rates of these triglycerides are markedly affected by pressure. At 500 psi, the reaction is truly non- selective, since fully saturated triglycerides are formed at IV of 70-80, whereas at 50 psi, trisaturated triglycerides are not formed at similar IVs. Analysis of the reaction products clearly show that, under the conditions employed, hydrogenation proceeds through definite pathways rather than random saturation of individual fatty acids within the triglyceride molecules. Reactivity was shown to be LLL > LLO > LLP. Linolenate containing triglycerides were shown to react slower than linoleate triglycerides. The HPLC data allows modeling of the reaction kinetics either by considering the reaction rate of the individual fatty acids within the triglycerides or by triglycerides individually. Other applications of the HPLC method include iodine value determinations, quality control within processing streams, and catalyst screening. High pressure hydrogenation shows promise for preparation of low trans margarine, spreads, and shortening oils.