Production of biodiesel from corn oil and ethanol by homogeneous alkali catalyzed transesterification

Abstract: This report gives a general overview on biodiesel production, its motivations, characteristics and recent developments, mainly focused in the Brazilian case. The Brazilian National Program for Production and Use of Biodiesel (PNPB) launched 2003 created a demand of biodiesel and stimulated the biodiesel production. Biodiesel is being produced from soybean oil, followed by animal fats and cottonseed oil, with palm and castor bean oil contributing in small portions. The biodiesel expansion has impacts on environmental and social issues such as deforestation from soya expansion and a decrease of employment levels due to the high degree of mechanization of the soya harvest. Experimental work was developed, using corn oil, ethanol and NaOH as a catalyst. Experiments were made varying significant parameters to find the optimum reaction temperature, reaction time, catalyst amount and molar ratio between ethanol and corn oil. Besides that, another experiment aimed to describe the yield behavior as a function of the reaction time. The produced biodiesel has been characterized by measurements of density, refraction index and viscosity. The amount of 0.4 wt % NaOH, based on the weight of raw oil, was enough to catalyze the reaction of transesterification effectively. A higher amount of alcohol in excess provides a higher yield at mild temperature conditions. But the higher amount of alcohol used, the higher the amount of alcohol in excess presented in the biodiesel phase which has to be eliminated. An increase of the temperature from 40˚C to 50˚C  does not increase the yield in a considerable way. Thus due to the energy saving it is not recommended to increase the temperature to 50˚C. Regarding the evaluation of the conversion as function of time, a high conversion is obtained after 90 min. An extension of the reaction time from 90 to 150min had no significant effect.