Selective hydrogenation of oo-rapessed oil with Cu/Cr catalyst.II.Geometric and positional isomerizations and effect of triacylglycerol structures on the reaction rate

lsomerization of double bonds in unsaturated fatty acids during 00-rapeseed oil hydrogenation with a Cu/Cr catalyst was studied. No trans isomerization of original monoenes was found. The trans monoenes formed in partially hydrogenated oil resulted from the polyene reductions, in this from trienes particularly. Comparing to the Ni catalyst, the Cu/Cr catalyst caused higher positional isomerization of double bonds mostly in the mono- and trienes. Unsaturated acyls in the extemal positions sn-1 and sn-3 of the triacylglycerol molecules were hydrogenated faster than those in the intemal position sn-2.