Supported gold catalysis in the hydrogenation of canola oil

Abstract

AbstractThe catalytic activity of gold supported on silica orγ‐alumina has been studied in the hydrogenation of canola oil. In the hydrogenation of butadiene and pentene using these catalysts, high stability, low yield oftrans‐isomers and high monoene selectivity have been reported in the literature.Catalysts containing 1% and 5% Au w/w on porous silica andγ‐alumina were active in hydrogenating canola oil in the range of 150 to 250 C and 3550 to 5620 kPa. The activity level of these catalysts was about 30 times lower than that shown by the standard AOCS Ni catalyst based on the concentration of metal (g Au/L oil). Up to 91% monoene content was obtained using these catalysts in comparison with a maximum of 73% for the AOCS standard Ni catalysts. Gold catalysts can be recovered easily by filtration and reused several times without a decrease in activity. The hydrogenated oil was nearly colorless. No gold was detectable in the oil. Contrary to claims in the patent literature, the gold catalyst produces higher concentrations oftrans‐isomers than does nickel. However, using gold catalysts the complete reduction of linolenic acid in canola oil can be achieved at a lowertrans‐isomer content in the products than that obtained by using the AOCS standard nickel catalyst.