Navegando por Autor "Borges, Igor Dalarmelino"

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    Arylsulfonamide chalcones as alternatives for fuel additives: antioxidant activity and machine learning protocol studies
    (2023) Duarte, Vitor Santos; Borges, Igor Dalarmelino; D´Oliveira, Giulio Demetrius Creazzo; Faria, Eduardo Coelho da Mata; Almeida, Leonardo Rodrigues de; Silva, Valter Henrique Carvalho; Noda Pérez, Caridad; Napolitano, Hamilton Barbosa
    Biodiesel is a promising fuel with the potential to reduce some negative aspects of fossil fuels, such as the emission of pollutants and greenhouse gases (GHGs), the scarcity of natural resources and market instability. To amplify its low durability and stability the use of technologies based on molecular compounds that reduce the oxidation rate of biodiesel and preserve its physical–chemical properties is very common and necessary throughout the world. To reduce oxidative stability problems of diesel–biodiesel blends, arylsulfonamide chalcones were evaluated as potential additives for B20 blends. In this study, comprehensive structural, computational, and experimental analyses were undertaken to understand the antioxidant potential of these compounds as possible additives. The supramolecular arrangements were stabilized by weak molecular interactions (C–H⋯O and C–H⋯π), which are related to antioxidant and antibacterial action, and groups can act as electron-donating substituents. The energy range of 593.1–570.2 kJ mol−1 in the frontier molecular orbitals indicates high structural stability, due particularly to sulfonamide groups which enable electrophilic attack. Furthermore, the Fukui function aligned with kinetics parameters, obtained using machine learning protocols, provided information to clarify and expand the comprehension of chalcone antioxidant features mediated by free-radical capture. The heat of combustion indicated good energy availability (6530.5–7306.5 kcal kg−1), close to those of conventional fuels. In addition, the oxidative stability of the diesel–biodiesel blend (B20) remained at around 27 hours, after 140 days of storage, which is better than for some commercial additives. We hope that this comprehensive study will support the understanding of chalcone-based compounds as alternatives to fuel additives.
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    A comparative structural analysis of arylsulfonamide chalcones with potential as a biofuel additive
    (2023) Vieira, Diego Freire; Borges, Igor Dalarmelino; Aguiar, Antônio Sérgio Nakao de; Duarte, Vitor Santos; D´Oliveira, Giulio Demetrius Creazzo; Vaz, Wesley Fonseca; Costa, Rogério Ferreira da; Noda Pérez, Caridad; Napolitano, Hamilton Barbosa
    Biodiesel has a significant added value compared to petrodiesel regarding a series of improved properties such as biodegradability and reduction of most regulated exhaust emissions. However, some challenges associated with biodiesel include physicochemical improvements in oxidative stability, which can be addressed by antioxidants. In this aspect, chalcone derivatives are simple chemical scaffolds with industrial applications that can be boosted by the insertion of a sulfonamide group. An extensive structure characterization was carried out for arylsulfonamide chalcone N-(2-(3–4-methoxyphenyl-propanoyl)-phenyl)-benzenesulfonamide and its isomer, to describe their supramolecular arrangements and conformational changes. Solid state arrangements were described by XRD and stabilized by C–H⋯O and π⋯π stacking interactions. Theoretical calculations were carried out by DFT using the M06-2X/6-311++G(d,p) level of theory to identify the reactive sites of arylsulfonamide chalcones and their molecular electrostatic potential maps. The fundamental factors were correlated to antioxidant molecules and commercial additives found in the literature. The analysis carried out in this work will be a gateway to confirm the relationship between the structure of arylsulfonamide chalcones and their additive properties as biofuels.
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    Insights into chalcone analogues with potential as antioxidant additives in diesel–biodiesel blends
    (2022) Borges, Igor Dalarmelino; Faria, Eduardo Coelho da Mata; Custodio, Jean Marcos Ferreira; Duarte, Vitor Santos; Fernandes, Fernanda de Sousa; Alonso, Christian Gonçalves; Silva, Valter Henrique Carvalho; Oliveira, Guilherme Roberto de; Napolitano, Hamilton Barbosa
    Biodiesel production is one of the promising strategies to reduce diesel consumption and an important contribution to climate change. However, biodiesel stability remains a challenging problem in biofuel use in the global energy matrix. In this context, organic additives have been investigated to minimize these problems and reduce harmful emissions to comply with fuel requirement standards. In this study, we discuss a comprehensive structural description, a behavior of B15 [85% volume of diesel and 15% volume of biodiesel (B100)] stability in the presence of antioxidants (chalcone analogues), and a theoretical calculation to pave the way for clarifying and expanding the potential of title compounds as an antioxidant additive for diesel–biodiesel blends. Finally, a systematic description of the oxidation stability was undertaken using a specialized machine learning computational pySIRC platform.