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United States Department of Agriculture

Agricultural Research Service

Title: Hydrogenation of Soybean Oil: Effects of Pressure and Temperature on Oil Properties

Authors
item Eller, Fred
item Teel, Jeffrey
item List, Gary

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: August 15, 2002
Publication Date: N/A

Technical Abstract: The effects of hydrogen pressure and reaction temperature on the hydrogenation of soybean oil were studied in an effort to minimize the amount of trans fatty acids while maintaining desirable characteristics for producing tub margarine basestocks. Temperatures ranging from 120 C to 170 C and pressures ranging from 15 psi to 200 psi were examined. In addition, several concentrations of nickel catalyst were also tested. For a given temperature, the rate of hydrogenation increased with pressure, however, so did the percent trans. Similarly, at a given pressure, the rate of hydrogenation and percent trans increased with the temperature. Although percent trans and iodine value were inversely proportional, in general, the lowest percent trans samples were from the treatments conducted at the lowest temperatures or highest pressures. At a temperature of 170 C, the selectivity of the hydrogenation reaction towards linoleate decreased with increased increase pressure, however, the selectivity towards linolenate did not change appreciably as the pressure increased. As the hydrogen pressure increased, the selectivity of the hydrogenation reaction increased towards linoleate while it decreased towards linolenate. Increasing the catalyst concentration increased the rate of hydrogenation, and the higher catalyst concentration resulted in an oil with a slightly lower percent trans content. At temperatures of 120 C to 140 C and a pressure of 100 psi, hydrogentated basestocks with about 15% trans can be produced. Such products when blended with liquid soybean oil, yield oils suitable for soft-tub margarines containing about 4% trans fatty acids. The blended oils have dropping points of about 32 C and solid fat contents of 8-9 at 10 C, 3-4 at 21.1 C, and 1-2 at 33.3 C.

Last Modified: 11/28/2014
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