Gel-combusted Ca-based catalysts for methanolysis of palm oil

•Submicron-sized CaO catalysts from gel-combustion synthesis.•Significant improvement of basic sites as compared with conventional ones.•Effective biodiesel production via methanolysis of palm oil.•FAME content >96.5% within 90 min and at mild reaction temperature of 60 °C.

Gel-combustion technique was applied to synthesize CaO catalysts for effective biodiesel production via palm oil methanolysis. The developed catalyst was a group of submicron-sized bonded CaO particles with meso-to-macro interparticle porous structure. Thus, this structure provided much smaller particle size, higher specific surface area and porosity, compared to the CaO from direct calcination of Ca nitrate or carbonate. Among the catalysts studied, the gel-combusted CaO exhibited the highest amounts of basic site, providing the highest catalytic activity in the methanolysis. The FAME content of >96.5% (Thailand national standard) was obtained over gel-combusted CaO within 90 min and at mild reaction temperature of 60 °C.

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