Biodiesel synthesis using cold-extracted fluted pumpkin seed (Telfairia occidentalis) oil via transesterification process

Abstract

Biodiesel is produced through the transesterification of vegetable oils or animal fats with methanol in the presence of a catalyst resulting in fatty acid methyl esters and glycerol as a by-product. The cold extraction method is preferred for oil extraction as it preserves the nutritional and physiochemical properties for oil better than conventional heat-based extraction methods. In this research work, cold-extracted fluted pumpkin seed oil was converted to biodiesel on 6:1 methanol-oil molar ratio at 65 ℃ for 60 minutes and NaOH as a catalyst. The result of the proximate analysis of the fluted pumpkin seed oil is as follows: Moisture content 28.1 %, Ash content 2.97 %, Protein content 14.2 %, Fat content 12.58 %, Fibre content 18.4 %. The following results obtained for the biodiesel production from the fluted pumpkin seed oil included: pH 7, kinematic viscosity: 14.2 mm²/s at 30 ℃, acid value: 0.54 mg KOH/g, flash point: 136 °C, fire point: 142 °C, pour point: 6 °C, saponification value: 6 mg KOH/g, iodine value: 58 g I₂/kg, peroxide value: 2.4 meq O₂/kg oil. The FTIR results revealed the absorption band at 3543.74 cm⁻¹ is assigned to the dimeric OH stretch and that at 3326.30 cm⁻¹ is attributed to the normal "polymeric" OH stretch, indicating the presence of hydroxyl groups involved in extensive hydrogen bonding networks and much more. The results aligned significantly with past literatures and reveal the efficiency of fluted pumpkin seed oil as a potential feedstock for biodiesel production.