Bifunctional mixed rare earth solid catalyst for biodiesel production from acid palm oil

Abstract

Solid mixed rare earth catalysts (MREEs) were synthesized by co-precipitation of raw mixed rare earth hydroxide cake obtained from monazite ore processing at different pH values (6, 7 and 12). The wavelength dispersive X-ray fluorescence spectroscopy (WDXRF) results show that MREEs catalyst co-precipitated at pH 12 contain high contents of active Ce, Nd, La and Y for facilitating both esterification and transesterification reactions. The synthesized MREE by co-precipitated at pH 12 and calcined at 300 °C possess high amounts of Lewis basic and acidic sites, allowing it to act as bifunctional catalyst. The catalyst shows high catalytic activity for the accelerating of the initial reaction rate and converting triglycerides/free fatty acid (FFA) into fatty acid methyl ester (FAME) in both esterification and transesterification reactions. Under the reaction conditions of 3 wt% catalyst, 20:1 methanol/oil molar ratio, 200 °C reaction temperature, 3.9 MPa reaction pressure and 600 r/min stirring rate, FAME conversion reaches 99.57% in 180 min of reaction time.