Thermodynamic analysis of excess molar enthalpy dynamics in mixtures containing ethanol, methanol, and alkoxyethanols as biofuels for enhanced combustion performance

• New data of H E for mixtures containing Ethanol, Methanol, 2-(2-Methoxyethoxy)ethanol, 2-(2-Ethoxyethoxy)ethanol, and 2-Methoxyethanol are reported. • The modified Redlich-Kister equation, NRTL and UNIQUAC models were used to correlate the experimental H E data of the studied mixtures. • Mixtures of alkoxyethanols and ethanol exhibited endothermic behavior, whereas mixtures of alkoxyethanols and methanol exhibited exothermic behavior. • The intermolecular effects involved in these binary systems have been discussed. The pressing need to find alternative fuels for environmental reasons has spurred the development of biofuels derived from biomass. These renewable energy sources reduce reliance on petroleum and lower greenhouse gas emissions. Ethanol and methanol are key biofuels that act as oxygenated additives, improving combustion efficiency and reducing air pollution. Ethanol, with its high oxygen content, boosts engine performance and cuts emissions, while methanol offers a cost-effective and versatile option. Research on alkoxyethanols-gasoline blends has shown substantial decreases in toxic pollutants, highlighting the importance of thermodynamic insights for advancing cleaner energy solutions. This study presents experimental data on excess molar enthalpies of fluid mixtures, encompassing ethanol and methanol combined with various alkoxyethanols, measured at two temperatures: 298.15 K and 313.15 K. Excess molar enthalpies were determined using a quasi-isothermal flow calorimeter at p = 0.1 MPa. Furthermore, the measured data were analyzed using a Redlich-Kister equation for fitting and correlated using Non-Random Two-Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models. The molecular interactions and thermodynamic behavior of the various studied binary mixtures at different temperatures are thoroughly examined and discussed.