Use of Natural Antioxidants in Biofuels: a Literature Review

Introduction: This paper presents a literature review on the use of biofuels, emphasizing the use of natural antioxidants, and addressing operational parameters and technological perspectives. The research has an exploratory-descriptive character, based on scientific articles, with emphasis on experimental studies evaluating the application of natural antioxidants in biodiesel. The analysis shows that oxidative stability is a critical factor to ensure fuel quality, being influenced by variables such as heat, light, presence of metals, and improper storage conditions, which affect properties such as acidity and viscosity. Traditionally, synthetic antioxidants are used to delay the oxidation process; however, they present limitations related to toxicity and environmental impacts. In this context, natural antioxidants emerge as promising and sustainable alternatives, capable of significantly improving the oxidative stability of biodiesel and meeting regulatory standards. It is concluded that the use of natural antioxidants is a viable strategy to replace or reduce the use of synthetic compounds, contributing to a cleaner and more sustainable production process, as well as encouraging new research on the use of residual biomass and abundant plant extracts in Brazil. Objective: The objective of this study is to present a literature review on the use of biofuels, with emphasis on the application of natural antioxidants, in order to evaluate whether these compounds constitute a viable strategy for reducing or even replacing synthetic antioxidants. Theoretical Framework: This section presents the main concepts and theories underpinning the research, focusing on the mechanism of radical auto-oxidation of fatty acid methyl esters, the influence of transition metals and environmental factors on fuel degradation, and the action mechanism of phenolic antioxidants in interrupting chain oxidation reactions. Method: The methodology adopted for this study has an exploratory-descriptive character, based on scientific articles, with emphasis on experimental studies evaluating the application of natural antioxidants in biodiesel. Results and Discussion: The results obtained indicate that the use of biofuels has shown continuous growth, while natural antioxidants stand out as promising and sustainable alternatives. These compounds demonstrate potential to significantly improve the oxidative stability of biodiesel, contributing to compliance with current regulatory standards. Research Implications: The practical and theoretical implications of this research are discussed, providing insights into how the results can be applied or influence practices in the field of biofuel technology and materials engineering applied to energy. These implications encompass the biodiesel production industry, the development of sustainable antioxidant additives, and research focused on the utilization of plant biomass and agro-industrial residues. Originality/Value: This study contributes to the literature by systematizing the use of natural antioxidants applied to biodiesel, focusing on sustainable alternatives to synthetic additives. Its originality lies in the comparative analysis of the efficiency of these compounds in the oxidative stability of the fuel. The results have practical relevance in supporting the development of more stable and environmentally sustainable biofuels.