Fluted pumpkin waste potential as a green solid bioalkaline catalyst for neem seed oil biodiesel synthesis

Developing green routes for biodiesel synthesis is essential for sustaining environmental benignity. Thus, this present study investigated the development of a solid catalyst using fluted pumpkin ( Telfairia occidentalis) pod husk as a bio-based raw material via high-temperature furnace heating, ranging from 300 to 1000 degrees C. The catalyst properties were examined by conducting surface functional group, surface crystallinity, surface area, and pore distribution analyses. The efficacy of the synthesized catalyst was investigated using 28 randomized experiments carried out on transesterification of esterified neem oil, which established 12:1, 3.5 wt%, and 60 min as optimal conditions for methanol/neem oil ratio, catalyst dosage, and reaction time, respectively, with a maximum neem seed oil methyl esters (NSOME) yield of 96.71 wt% through response surface methodology. The statistical assessment of the developed model gave a correlation coefficient (R) of 0.9907 and a coefficient determination of 0.9816 (R2). The physicochemical properties of the NSOME agree with the American standard limits, making it suitable for transportation and energy purposes. The catalyst could be deployed for three reaction cycles with high turnover frequencies. Hence, fluted pumpkin waste and neem oil are suitable as a green route for biodiesel synthesis.