Estudo dos efeitos do tween 20 na produção do biodiesel em ultrassom de baixa potência.

Abstract

The search for environmentally friendly fuels to meet the needs of the transportation sector has driven researchers to investigate and improve the production of biofuels from accessible sources, aiming to offer sustainable and economically viable production. Among the fuel alternatives, biodiesel stands out as an option for diesel engines due to its physical and chemical similarities. The most common route for the synthesis of biodiesel is the transesterification reaction of nonpolar lipid substances with short-chain polar alcohols. However, the difference in polarity between the reactants can hinder mass transfer in the reaction system, resulting in loss of product yield. The inclusion of surfactant substances in the transesterification reaction has been a strategy to reduce this difficulty, promoting better contact between the phases and, consequently, reducing the amount of reagents required, the reaction time and the temperature, while increasing the final yield. Low-cost soybean oil has been considered a promising raw material for biodiesel production, not only in Brazil but also in several regions of the world. In addition to fostering domestic production, biofuel production benefits many people, generating jobs and significant revenue annually. This study aimed to evaluate how reaction conditions affect biodiesel production performance. Furthermore, biodiesel was synthesized from the transesterification reaction of soybean oil, using low-power ultrasound (110 W) and the commercial surfactant Tween 20 as an additive. Methanol was chosen as the short-chain alcohol and potassium hydroxide as the catalyst. Initially, triplicate experiments were performed with different surfactant concentrations, seeking to determine the best m/m fraction for the reaction system. Then, a 2³ experimental design with repetition at the central point was used to optimize the reaction conditions, considering as independent variables the alcohol:soybean oil molar ratio, reaction time and temperature. The model analysis was performed using table of effects, ANOVA and response surface graphs. The results indicated that the best surfactant concentration was 0.5% m/m, and the maximum yield achieved was 93.22% m/m of biodiesel, under the optimal conditions of molar ratio, 4:1, reaction time of 15 minutes in an ultrasonic bath at 30 °C.