Characteristics and catalytic behavior of NiAlCe catalysts in the hydrogenation of canola oil: the effect of cerium on cis/trans selectivity

Abstract

A series of co-precipitated cerium-promoted nickel–aluminum catalysts was prepared. The physicochemical properties of the precursors were analyzed by means of various methods including XRF, HT-XRD, TPR, surface area and thermal decomposition as well as porosity measurements. The activity and selectivity of the NiAlCe catalysts in the hydrogenation reaction of canola oil were investigated and the results compared to those for the cerium-free catalyst. Besides improving some physicochemical properties of the precursors, the addition of cerium significantly improved the cis/trans selectivity, yet at the expense of some loss of the activity in case of larger cerium loadings. Upon addition of a relatively low amount of cerium (0.67 wt%) the content of the C18:1 trans fraction decreased by ca. 35 %. Together with the synergistic effect of the hydrogen pressure a significant decrease of the C18:1 trans fraction by ca. 48 % could be achieved. Furthermore, compared to the cerium-free catalyst, the addition of cerium resulted in a slower drop of the C18:1 cis fraction and a slower increase of the C18:0 fraction in time during the hydrogenation process.