Microwave-mediated conversion of Kusum seed oil into biodiesel and optimization using RSM-central composite design

In this research, a two-step microwave-assisted conversion was studied to boost the yield of non-edible Kusum seed oil based biodiesel. Pretreatment involving esterification using silicotungstic acid was carried out to reduce the oil's acid value from 17.7 to less than 2. The oil was then treated with Ba(OH) 2 catalysts to turn it into esters. The response surface technique with central composite design was adopted to investigate and to improve biodiesel yield by fine-tuning four parameters: molar ratio of methanol to oil, amount of catalyst, temperature, and reaction time. The experimental results of KOME yield based on response surface methodology involving central composite design were modelled and effectively fitted by a second-order polynomial. The analysis of variance (ANOVA) of the model showing close agreement among R 2 , Adjusted-R 2 , and Predicted-R 2 suggested high predictability with experimental KOME yield well. The response optimizer yielded a maximum KOME yield of 96.7 % at 10.8:1 methanol to oil molar ratio, 2.08 wt% Ba(OH) 2 catalyst, 62.75 °C temperature, and 4.46 min of reaction time. The interactive graph showed that molar ratio, temperature, catalyst, and time all had a significant influence on biodiesel yield. The FTIR characterization of Kusum oil vs. KOME and 96.31 % biodiesel yield calculated in 1 H NMR were in close agreement with the model value. The physicochemical properties of KOME were comparable to ASTM D 6751–12 standards. • Microwave-assisted biodiesel synthesis from non-edible Kusum seed oil was carried out using Ba(OH) 2 catalyst. • Response surface methodology was used for optimizing the Kusum oil transesterification using Ba(OH) 2. • Highest 96.7 % KOME yield was obtained at 10.8:1 methanol to-oil molar ratio, 2.08 wt% Ba(OH) 2 , 62.75 °C, and 4.46 min. • The properties of KOME were in close agreement with the biodiesel standards.