Produção de Biodiesel pela transesterificação alcalina homogênea do óleo de soja refinado com metanol com irradiação de microondas

Abstract

The search for alternative and renewable sources of liquid fuels due to the scarcity of mineral reserves combined with a new environmental awareness has received considerable attention in recent years. In this current scenario alkyl esters of fatty acids derived from vegetable oils or animal fats (biodiesel) has gained greater prominence because it is a biodegradable fuel, non-toxic, environmentally friendly, derived from renewable sources and especially the possibility to replace partially or completely the diesel oil. The chemical reaction that turns esters of long chain into mono alkyl esters is called transesterification. This work had the objective to evaluate the influence of the microwaves in the tax of conversion of biodiesel from the reaction of homogeneous alkaline transesterifiction. For this a domestic equipment of microwaves without any alteration in its structure was used. As raw material, source of glicerídeos, oil of fine soy, methanol as solvent was used and agent alquilate and as catalytic, the hidroxide of potassium (KOH). It was still studied the influence of initial concentration of catalyst, the concentrations of 0.5, 1.0 and 2.0% using the reaction times of 10, 20 and 30 seconds to evaluate the mass conversion and final viscosity of biodiesel. The molar ratio methanol/oil 6:1 and power of 100% of the microwave equipment were kept constant. All reactions were performed without the aid of mechanical agitation. The best results of conversion and viscosity for biodiesel were obtained with an initial concentration of catalyst of 1.0% in 10 seconds of reaction. The final temperature of reaction was the boiling temperature of alcohol. Conversion weight and viscosity obtained for these conditions were of 97.08% and 10.25 cSt (mm2 /s) measured at 25°C, respectively. The concentration of catalyst of 0.5% showed to be insufficient, within the time range studied, and with the concentration of 2.0% there was a great loss of the final product.