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a b s t r a c tThis work investigated the potential of shea butter oil (SBO) as feedstock for synthesis of biodiesel. Due to high free fatty acid (FFA) of SBO used, response surface methodology (RSM) was employed to model and optimize the pretreatment step while its conversion to biodiesel was modeled and optimized using RSM and artificial neural network (ANN). The acid value of the SBO was reduced to 1.19 mg KOH/g with oil/ methanol molar ratio of 3.3, H 2 SO 4 of 0.15 v/v, time of 60 min and temperature of 45 C. Optimum values predicted for the transesterification reaction by RSM were temperature of 90 C, KOH of 0.6 w/v, oil/ methanol molar ratio of 3.5, and time of 30 min with actual shea butter oil biodiesel (SBOB) yield of 99.65% (w/w). ANN combined with generic algorithm gave the optimal condition as temperature of 82 C, KOH of 0.40 w/v, oil/methanol molar ratio of 2.62 and time of 30 min with actual SBOB yield of 99.94% (w/w). Coefficient of determination (R 2 ) and absolute average deviation (AAD) of the models were 0.9923, 0.83% (RSM) and 0.9991, 0.15% (ANN), which demonstrated that ANN model was more efficient than RSM model. Properties of SBOB produced were within biodiesel standard specifications.

The present work was aimed at assessing the possible use of ripe plantain fruit peel as a green-base catalyst in synthesizing Azadirachta indica oil methyl esters (AIOME). The free fatty acid content of the oil (5.81 wt %) was initially reduced to 0.90 wt % using methanol: oil at 2.19 v/v, Fe 2 (SO 4 ) 3 at 6 wt %, time of 15 min and temperature of 65 • C. The pretreated oil was converted to AIOME in a transesterification process with calcined ripe plantain peel ash (CRPPA) at 700 • C as catalyst. The process was modeled by artificial neural network and optimized using genetic algorithm. The effectiveness of the developed CRPPA is ascribable to its high K content and microstructural transformation. The reliability of the model obtained was confirmed with a high coefficient of determination (R 2 ) of 0.996 and a low mean relative percentage deviation (MRPD) of 8.10%. The best operating variables combination for the process was methanol:oil of 0.73 v/v, CRPPA of 0.65 wt % and time of 57 min while the temperature was kept constant at 65 • C with a corresponding AIOME yield of 99.2 wt %. The results of this work demonstrated the potentials of ripe plantain peels and neem oil as cheap feedstocks for biodiesel production.

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