PRODUCTION AND CHARATERIZATION OF BIODIESEL FROM NEEM OIL

ABSTRACT This study investigates the production and characterization of biodiesel derived from neem oil (Azadirachta indica) a non-edible, abundantly available, and underutilized plant oil with high free fatty acid (FFA) content. Neem oil was extracted and subjected to physicochemical analysis, which revealed properties such as a pH of 6.4, density of 0.96 g/cm³, viscosity of 243.7 mm²/s, and flash point of 229.5 °C. Due to its high FFA content (1.42 mg KOH/g), a two-step transesterification process was employed: acid-catalyzed esterification using sulfuric acid to reduce FFA, followed by base-catalyzed transesterification using sodium hydroxide and methanol. The resulting biodiesel was purified and analyzed for key fuel properties. The biodiesel exhibited a specific gravity of 0.91, viscosity of 3.52 mm²/s, acid value of 0.40 mg KOH/g, FFA content of 0.25%, and cetane number of 52.4, all within the acceptable limits of ASTM D6751 and EN 14214 standards. Its flash point (176 °C) indicates excellent storage safety, while the pour point (-2.5 °C) and cloud point (5.2 °C) confirm its suitability for warm to moderate climates. Characterization using Fourier Transform Infrared Spectroscopy (FTIR) confirmed successful transesterification, with prominent ester peaks (C=O stretch at 1740 cm⁻¹) and signatures of long-chain fatty acid methyl esters. This research confirms that neem oil is a viable feedstock for producing high-quality biodiesel, offering good combustion characteristics, oxidative stability, and low emission potential. The study contributes to renewable energy development by providing a cost-effective, non-food-based fuel alternative that addresses both energy security and environmental sustainability. Further studies on improving cold flow properties, large-scale processing, and optimizing engine performance are recommended to promote the industrial adoption of neem biodiesel.