Transesterification reaction from rice bran oil to biodiesel over heterogeneous base calcium oxide nanoparticles catalyst

Abstract

This study focuses on the development of an alkaline earth metal oxide, calcium oxide (CaO) as heterogeneous base catalyst for biodiesel production. The intention for this study is to explore potential for the transformation of commercial calcium carbonate, CM-CaCO3 into CaO nanoparticles and further used as a heterogeneous base catalyst in single step transesterification reaction from rice bran oil to biodiesel. The prepared CaO was calcined under 10-3 mbar vacuum, at temperatures ranging from 100°C to 700°C. TGA-DTA results revealed that the CM-CaCO3 must be calcined above 600°C in order to form CaO. This is in accordance with FTIR results which specified the complete formation of CaO at 700°C. XRD revealed that the rhombohedral CaCO3 and hexagonal Ca(OH)2 had completely been disappeared, leaving only crystalline cubic CaO at 700°C. Interestingly, the larger BET surface area (11.5 m2g-1) and highest basicity (1.959 mmol/g) were observed for CaO calcined at 700°C (CaO-700). The CaO-700 nanoparticles were designated as a catalyst for the transesterification reaction of rice bran oil to give biodiesel. NMR and GC-FID results further confirmed the successful formation of biodiesel using CaO-700 as catalyst.