Application of Bifunctional Catalyst in Optimization of Transesterification of Delonix Regia Seed Oil via One-pot Production Route

Renewable energy is central to all sustainability developments in the environment, economy, and technology sectors. This study developed a new pathway to achieve biodiesel production from Delonix regia oil using a bifunctional heterogeneous catalyst. Delonix regia oil (DRO) was extracted using n-hexane in the Soxhlet extraction set-up. The acid value and viscosity of extracted DRO necessitated a two-step treatment to produce biodiesel. Eggshell served as the precursor for the synthesized bifunctional catalyst. The precursor was calcined at 700 °C for 3h and further treated with 7M Sulphuric acid for 4h. The synthesized catalyst was characterized using elemental dispersive X-ray, X-ray diffraction, Fourier transform Infrared, and Scanning electron microscopy techniques. Extracted DRO was transesterified in a one-pot process using a synthesized bifunctional catalyst as modeled by the Taguchi orthogonal design having MeOH/oil molar ratio, temperature, reaction time, and catalyst dosage as process inputs. Characterization showed that the synthesized bifunctional catalyst was porous, and the presence of both acid and base groups was confirmed on the catalyst surface. An optimal condition for DR biodiesel production was a MeOH/oil molar ratio of 12:1, temperature of 70 °C, reaction time of 60 mins, and catalyst dosage of 1.5 wt.% with a corresponding biodiesel yield of 89.45 wt.%. The produced biodiesel met standard specifications as outlined in ASTM D6751 and EN 14214 documents. The Synthesized bifunctional catalyst showed tremendous catalytic efficiency in producing biodiesel from DRO. The designed pathway could enable biodiesel production to contribute to renewable energy sustainably.