Lanthanum oxide behavior in La2O3-Al2O3 and La2O3-ZrO2 catalysts with application in FAME production

Abstract

La2O3 monolayer catalysts with 90% coverage on Al2O3 and 71% on ZrO2 were successfully obtained by a sol–gel method and the catalytic performance evaluated as fatty acid methyl esters (FAME) production in a canola oil transesterification reaction show differences upon the nature and extent of basic sites. The La2O3 monolayer does not modify strongly the textural properties of the Al2O3 and larger structural changes are detected on ZrO2. For the La2O3-Al2O3 monolayer catalyst, the inter-diffusion Al3+/La3+ cation modify the nature of the acidity and increases the basicity of the Al-O-La species, whereas for the La2O3-ZrO2 monolayer catalyst, appearance of tetragonal ZrO2 structure with larger basicity is detected. The effect of the nature of the support in the catalytic performance in FAME production of the La2O3-ZrO2 and La2O3-Al2O3 monolayer catalyst informed as FAME % (60% at 5 h and 65 °C) for the La2O3-ZrO2 is attributed to the presence of the new medium strength basic sites and the m-ZrO2 structure, whereas the lower basicity of the La2O3-Al2O3 explain the lower fatty acid methyl esters production (45% at 5 h and 65 °C).