Assessment of Physicochemical and Fatty Acids Composition of Crude Seed Oil Extract of Azadirachta indica Adr. Juss. for its potential in Biodiesel Production

Abstract

This study investigates the physico-chemical and fatty acids composition of crude seed oil extracts of Azadirachta indica . The main objective was to evaluate some biodiesel characteristics of the crude seed oil extract of Azadirachta indica. The procedures of the Association of Official and Analytical Chemist (AOAC) were used for assessment of some physical, biochemical, and fatty acids constituents of the test seed oil extract. The physical properties assayed for indicate that the oil is liquid at room temperature, non-drying, with specific gravity, with flash and melting points of 0.910±0.08 g/cm3, 80±2.10°C and 76±1.60°C respectively. The chemical properties included 66.77±2.55 g/100g (iodine value), 1.465±0.07 (refractive index@ 30°C), 212.96±1.16 mgKOH/g (saponification value), 0.39±0.16 meq/Kg (peroxide value), 4.24±0.12 mgKOH/g (acid value), 2.20±0.12 mm²/s (viscosity value), 56.91±2.19 (cetane number), 39.21±1.11 MJ/kg (calorific value) and 2.13±0.05% w/w (free fatty acids). Fatty acids composition of the crude seed oil of A. indica obtained were linoleic, hexadecanoic, octadecanoic and alpha linolenic acids, with retention time and % composition of 18.2 min and 10.8±0.50%, 22.2 min and 30.01±1.79%, 18.2 min and 59.10±2.22%, and 20.2 min and 0.09±0.02% respectively. The crude seed oil extract clearly presents a potential as a biodiesel substrate for incorporation as a proximate blend in auto-engines. This therefore would necessitate intensive afforestation efforts of the plant species for sustainable utilization.

Keywords: Azadirachta indica, Biodiesel, physico-chemical, fatty acids, crude seed oil, extracts