Optimization of Transesterification of Lophira lanceolata (False Shea) Seeds Oil to Alkyl Esters using Response Surface Methodology

Abstract

This research work studied the production and optimization of biodiesel from seeds oil of Lophira lanceolata (False Shea). The esterification reaction was carried out using conc. H₂SO₄ (1% v/v) as acid catalyst with methanol/oil ratio of 4.5:1 at a temperature of 55^oC for 90min to reduce the FFAs contents (< 0.32%).The reaction mixture was transesterified to Lophira lanceolata methyl esters (LLMEs) using NaOH as base catalyst. The biodiesel produced was analyzed for fuel properties using ASTM standard methods. Optimization of LLMEs production from its oil was performed by central composite design and response surface methodology in 30 experimental runs. The optimization result suggested the best combination of process for Lophira l. optimum biodiesel yield of 85.0% variables are as follows: reaction temperature (50^oC); reaction time (120 min); methanol/oil ratio (9:1) and catalyst conc. (0.30 mol/dm-3) respectively. The regression equation obtained by ANOVA showed that the model was adequate to express the actual relationship between the response (biodiesel yield) and significant variables with a satisfactory coefficient of determination R² of 96.05 % and adjusted R2 of 94.64% for Lophira l. and Adjusted R² of 98.04% for biodiesel fuels, which can be compared favourably with the prediction model value of (83%). Fuel properties of the biodiesel produced conform to the ASTM specifications, which suggest that; it would make a good alternative fuel for diesel engines.

Key words: Lophira lanceolata, Optimization, LLME Yield (%), Behnken design, Lower/Upper levels