Transesterification of Camelina sativa Oil Catalyzed by Mg/Al Mixed Oxides with Added Divalent Metals

This paper is focused on the heterogeneously catalyzed transesterification (in a batch reactor) of vegetable oil, including the determination of leached metals. The oil was obtained from the short-season crop Camelina sativa. The reaction was catalyzed by mixed oxides, which were synthesized from Mg/Al hydrotalcites with built-in different types of divalent cations such as Mn, Ca, Co, Ni, and Fe. The various physicochemical properties like the structure by X-ray diffraction, acidity, basicity, and textural properties were measured and the effect of the added cation type on catalyst properties and activity was compared. A noticeable relationship between the cation type and catalytic activity in the transesterification reaction was observed. The highest ester content of 96.6 wt % after 7 h of transesterification was observed for catalysts with nickel and iron. The statistical analysis of results showed that the catalyst activity was mainly influenced by middle-temperature basic sites. The novelty lies in transesterification over five different heterogeneous catalysts-mixed oxides with added divalent metals at the same reaction conditions of C. sativa oil.