Promising extruded catalyst for palm oil transesterification from LiAlH4 hydrolysates

Abstract

Transesterification catalysts prototypes of LiAlP/montmorillonite from LiAlH4 hydrolysates (LiOH-Al(OH)3) have been synthesized and extruded. The extruded catalysts preserve the basic structure of montmorillonite K10 according to X-ray diffraction results, which promote transesterification of triglycerides present in palm oil with methanol to generate FAMEs. Palm oil conversions of up to 89.7% were achieved in a batch reactor at 200 °C, 40 Kg/cm2, and MeOH:Oil molar ratio of 18:1. The results obtained suggest that the good catalytic activity of the extrudates is due to the adequate combination of the Lewis acid sites and the mesoporous structure obtained during the reaction between the montmorillonite, phosphoric acid and LiOH-Al(OH)3. By mean of B3LYP/6-31G* calculations, the behavior of the electrophilicity for the palm oil triglycerides and the corresponding H, Li and Al cations is remarkable, the highest electrophilicity for cation is in this order: H > Al > Li and more important for triglyceride aluminum cation in which palmitoyl moiety is in the methine carbon of glycerol moiety.

Keywords

• Biodiesel
• Triglyceride transesterification
• Montmorillonite
• LiAlH4 hydrolysates
• DFT calculations