Exploring quinolinone–chalcones: Synthesis, antioxidant potential and industrial applications in biofuels

Biofuels undergo oxidative degradation, which reduces their storage stability and efficiency, hindering their large-scale adoption and integration into the global energy matrix. To address this issue, we synthesized and characterized four novel quinolinone–chalcone derivatives (substituted with Br, Cl, OCH3 and OCH2CH3) as potential antioxidant additives. Structural analysis, density functional theory calculations and machine learning-based hydroxyl radical scavenging rate evaluation were performed to assess the influence of the substituents on stability and antioxidant capacity. Single-crystal X-ray diffraction revealed C–H···O and C–H···π interactions contributing to supramolecular stability, while electronic property analysis indicated enhanced kinetic stability and regions near the sulfonamide group prone to nucleophilic attack. Machine learning predictions showed that the bromine derivative exhibited a hydroxyl radical scavenging rate of 7.97 × 109 m−1 s−1, comparable with the commercial antioxidant butylated hydroxytoluene (4.34 × 109 m−1 s−1). These findings highlight the potential of quinolinone–chalcone derivatives as efficient antioxidant additives, improving the oxidative stability and sustainability of biofuels.