Jackfruit (Artocarpus heterophyllus) Seeds as Effective Heterogeneous Catalyst For Biodiesel Synthesis from Soybean Oil

Abstract

Here, we demonstrate the utilization of calcined jackfruit seeds as highly efficient heterogeneous base catalysts (JSC-400 and JSC-600) for biodiesel synthesis from soybean oil. Catalysts were characterized by PXRD, FTIR, \({\text{N}}_{2}\)-adsorption, SEM–EDX, FETEM, XPS, Hammett and CO₂-TPD techniques. PXRD and FETEM analysis confirmed the presence of mixed metals in their oxide and carbonate forms, and their polycrystalline structures, respectively. FESEM and \({\text{N}}_{2}\)-adsorption revealed the spongy, flake-like morphology and mesoporous structure of the catalysts. The concentration of potassium (K) in JSC-400, which is responsible for its basicity, was evaluated using EDX (12.40 atomic%) and XPS (13.87 atomic%). JSC-400 showed a more promising biodiesel yield (97.7%) in 30 min, which might be due to the higher basicities of JSC-400 with 11.51, 0.42 mmol/g and 1.997 mmol/g than JSC-600 (11.51, 0.42 mmol/g and 1.997 mmol/g) as measured by pH, Hammett and TPD-CO₂ techniques, respectively. Three times consecutive recycle study of JSC-400, showed no significant loss in yield (95.2%), compared to fresh catalyst (97.7%). Thermodynamic and kinetic studies confirmed the non-spontaneous and pseudo-first order reaction, respectively. Product was confirmed by FTIR, ¹H and ¹³C NMR and GC–MS techniques, and fuel properties were found to be comparable with the literatures and international standards.