PRODUÇÃO DE BIODIESEL A PARTIR DO ÓLEO VEGETAL DE BABAÇU (Orbignya martiniana) EMPREGANDO CATALISADORES HETEROGÊNEOS COMERCIAIS

Abstract

Nowadays, the biodiesel production is made, mainly, for the basic catalytic route homogeneous using as catalysts KOH and NaOH. However, this route presents some disadvantages, such as: esters saponification and difficult removal of the catalyst. Otherwise, the heterogeneous route catalytic avoids the inconveniences of the homogeneous catalysis, reducing the amount of aqueous effluents generated in the process and the utilization again of the catalysts. The present work had as objective to select commercials heterogeneous catalysts and to evaluate the catalytic activity of them in the transesterificação reaction of the babassu oil with methanol. In this work, were used carbonatos (Li2CO3, CaCO3), oxides (CaO, MgO, La2O3, Al2O3, SiO2, ZnO) and bases (Ba(OH)2 mono and octahidratado) and clays (bentonita and sea calcium). The catalytics tests were monitored using the Thin Layer Chromatography. The biodiesel obtained was analyzed physical-chemically and characterized by Gas Chromatography and Infra red. The selected catalyst the Ba(OH)2 mono and octahidratado was characterized by the techniques of the Infra red, Optical Microscopy, DRX, solubility and melting point. The results showed that the catalysts CaO, MgO, La2O3, Li2CO3, Al2O3, SiO2, ZnO, CaCO3, pure clay of sea calcium, sodic and pure bentonita presented low catalytic activity for biodiesel production. On the other hand, the catalysts CaO, MgO, sodic bentonita clay and the Ba(OH)2 mono and octahidratado were active to the biodiesel obtaining presenting conversion above 90 %. It was verified that the Ba(OH)2 presented good results in relation to the other catalysers due its complexity of interaction with alcohol molecules in the reaction, what favored a good catalytic activity and selectivity for the production of biodiesel. The reaction transesterification with the Ba(OH)2 monohidratado was evaluated statistically by a factorial planning 24 with central points, varying the time of reaction of 1 - 3 hours, the catalyst concentration 0,2 - 1,0 %, ratio molar alcohol: oil between 6 and 12:1, temperature among 80 160 ºC using as answers the yield of the biodiesel in mass and the esters content. The best conditions for the yield in mass were: temperature of 80 ºC, 3 hours reaction time, ratio molar alcohol: oil 12:1 and concentration of the catalyst Ba(OH)2 monohidratado activated 0,2 %. The factorial planning showed that the variation of the factors didn't have significant influence in the conversion of the esters.