Chalconas e Benzimidazóis : desenvolvimento de aditivos em misturas de biocombustíveis

Abstract

The scarcity of natural resources and the challenges posed by climate change are problems that are related to the crisis permeating the global economic system. Leaders from all around the world are discussing solutions to these environmental problems, such as reducing emissions of conventional pollutants and greenhouse gases (GHG), as well as exploring alternatives to the energy crisis, which is considered a global emergency. The global economic system is highly dependent on natural resources, particularly fossil fuels such as oil, coal, and natural gas. In fact, more than 80% of the energy consumed worldwide comes from these non-renewable sources. The imminent scarcity of these resources is worrying, due to human development and population growth, in addition to the increasing pollution generated by the combustion of fossil fuels. In this context, the synergism of fossil fuels with renewable fuels represents a sustainable option that can reduce pollutant emissions by creating an alternative energy matrix. Biofuels, for example, represent a viable alternative for reducing pollutants and a sustainable energy option. Biodiesel is an example of a renewable and promising biofuel that can be obtained from renewable biomass. It is biodegradable and can be used in diesel engines without major adaptations, in addition to presenting lower levels of pollutant emissions and toxicity compared to fossil fuels. However, the lower energy availability and low oxidative stability of this fuel generate a series of problems that hinder its use. Due to this, technologies are studied every day to mitigate these problems. A good example is additives, which are substances that delay the oxidation and early degradation of the fuel. Additives can be developed from organic molecules that have desired properties such as antioxidants or antimicrobials. In this sense, this thesis presents a study of the structural aspects of organic molecules from the class of chalcones and benzimidazoles. Theoretical studies were also carried out to understand the physicochemical properties of these molecules, combined with simulations and machine learning methods that contributed to the understanding of aspects related to antioxidant activity. From a structural and theoretical perspective, experimental tests have determined that the molecules studied in this thesis act as antioxidant agents, making them suitable additives for diesel-biodiesel blends. We also emphasize that these molecules acting as an additive can contribute to the use of biofuels, thereby supporting the maintenance of natural resources and the environment.