Synthesis and Physico-chemical Studies of Base Catalyzed Methanolysis of Some Virgin Tropical Seed Oils

The physico-chemical characterization of Prunus amygdalus, Dacryodes edulis and Chrysophillum albidium seed oils were investigated, together with their methyl esters. The vegetable oils were extracted by applying the solvent extraction method, using n-hexane. Prunus amygdalus had the highest oil yield (60.1%), followed by Dyacrodes edulis (55.76 %) and least from Chrysophillum albidium (13.67%). The oils and their biodiesel were then analyzed for acid value, free fatty acid, specific gravity, ash content, iodine value, peroxide value, saponification value, kinematic viscosity, flash point, smoke point, titre value, cloud point, moisture content and refractive index. Accordingly, Dyacrodes edulis seed oil had the highest acid value of 6.57 and required two-step transesterifictaion. The produced biodiesels were discussed in the light of ASTM D 9751, ASTMD 6751 and DIN 14214. These showed yields of 94.36%, 93.03% and 86.49%, cetane numbers of 70.40, 55.20 and 64.57 and calorific values of 31,178.39 KJ/kg, 34,421.50 KJ/kg and 32,838.38 KJ/kg for Prunus amygdalus, Dacryodes edulis and Chrysophyllum albidium, respectively. Other fuel-related properties showed highly improved qualities upon transesterification and compared well with ASTM and EU standards. The overall results showed that the seed oils are viable for biodiesel production.