Optimization of Neem oil esterification using response surface methodology

Abstract

High production cost of biodiesel as well as food-versus-fuelcrisis within the economy have led to the adoption of non-edible feedstock over edible feedstock, the high FFA associated with the former remains a challenge. Esterifying high free fatty acid (FFA) oil with acid is necessary to avoid soap formation during biodiesel production. Thus, this study evaluated the efficacy of response surface methodology (RSM) in modelling the esterification process for neem seed oil (NSO) with a high FFA catalyzed by sulphuric acid H2SO4. A central composite design (CCD) with two level-three factors (23) was applied to examine the influence of Reaction time (60-120 minutes), Catalyst concentration (1.0-3.0 w/w,%), methanol to oil ratio (0.20-0.60w/w,%) and constanttemperature at 60oC on reduction of the high FFA (4.77%) of neem. The Optimum conditions for the esterification process is 0.67 % FFA at 0.4 Methanol to Oil ratio; 90 min. Reaction Time; and 2 (w/w) % H2SO4Catalyst Concentration. Statistics for the RSM model showed that the correlation coefficient (R2) value (0.9457) is relatively high, close to 1, which is desirable and is in reasonable agreement with the adjusted R2 value (0.8969).