Microwave-Enhanced Alkali Catalyzed Transesterification of Kenaf Seed Oil

A two-step process assisted by microwave irradiation was used to produce kenaf oil methyl ester. The first stage made use of sulfuric acid catalyst to convert free fatty acids into methyl ester, while the second made use of potassium hydroxide catalyst under microwave irradiation to transesterify the triglycerides. The four major experimental variables considered in the latter step were catalyst concentration, alcohol-oil molar ratio, reaction temperature and reaction time. The results were analyzed statistically for the effect of those variable parameters on the reaction conversion. Optimum conversion of about 94% was obtained at the optimum values of variables 0.55% KOH catalyst, 4.5:1 methanol-oil molar ratio, 57.5oC and 6.5 minutes reaction time. The analyses on the biodiesel produced by this method proved to be acceptable in comparison to ASTM biodiesel standard.