Optimization Study on Trans-esterification of Cottonseed Oil with Butyl Alcohol for Biodiesel Production Using Response Surface Methodology

Cottonseed oil was extracted by solvent extraction method using N-hexane as an extracting solvent. Biodiesel was synthesized by transesterification of the oil with butanol using sodium hydroxide (NaOH) as catalyst. Influence of tranesterification process parameters including Catalyst concentration (wt%), Butanol/oil molar ratio, temperature, reaction time, and agitation speed on the yield of biodiesel were investigated and optimized using Central Composite Rotatory Design (CCRD) of Response Surface Methodology (RSM) and analysis of variance (ANOVA). Significance of different process parameters and their combined effects on the transesterification efficiency were established through a full factorial central composite design.The findings of the study agreed with results from studies on transesterification of the oil with other alcohols and for other vegetable oil. It was also in good agreement with various international standards for biodiesel fuel. Validation process perfomed based on the optimal conditions of Catalyst conc.(%wt oil) 0.5, Butanol/oil molar ratio, 19, Temperature (oC), 40 and agitation speed (rpm), 300 achieved a yield of 75% which is in very close range with the predicted yield of 74.59% . Findings of this study showed that butyl alcohol is an alternative alcohol for the synthesis of biodiesel from cottonseed oil.