Production of Biodiesel from African (schweinfurthii) Oil via Transesterification Using Response Surface Methodology

The increasing global energy demand, depletion of fossil fuel reserves, and environmental concerns have intensified the search for sustainable alternative fuels. This study investigated the production and optimization of biodiesel from African elemi (Canarium schweinfurthii) oil through base-catalysed transesterification using sodium hydroxide (NaOH) and Central Composite Design (CCD) in Design-Expert software. The study involved oil extraction, physicochemical characterization, process optimization, biodiesel production, and product characterization. Mechanical extraction produced oil containing 71.46% volatile matter and several long-chain fatty acids, including oleic, palmitic, linoleic, myristic, decosenoic, octanoic, tetradecanoic, pentanoic, eicosanoic, and heptacosanoic acids. The initial high acid value of the oil was reduced through acid esterification using hydrochloric acid (HCL). A total of 30 experimental runs were conducted to optimize the effects of reaction temperature, catalyst concentration, methanol-to-oil ratio, and reaction time. The optimum conditions of 70°C, 120 min, 1.0 wt.% NaOH, and a 1:1 methanol-to-oil ratio produced the highest biodiesel yield of 95.2%. The gas chromatography and mass spectroscopy (GC–MS) analysis confirmed fatty acid methyl ester (FAME) conversions of 88–97%, while the Fourier Transform Infra-Red Spectrophotometer (FTIR) analysis identified characteristic functional groups associated with biodiesel. The biodiesel exhibited flash point (126–150°C), viscosity (4.8–6.7 cP), density (0.95–1.00 g/cm³), acid value (0.69–2.56 mg KOH/g), calorific value (34–36 MJ/kg), and cetane number (45.92–46.19), indicating satisfactory fuel properties. The findings demonstrate that African elemi oil is a promising feedstock for biodiesel production and that CCD effectively optimizes the transesterification process for high biodiesel yield.