The transition toward sustainable energy systems requires renewable fuel alternatives with optimized combustion performance and reduced emissions. 5-Methylfurfural (MFF), a lignocellulosic biomass-derived furanic compound, has emerged as a promising biofuel precursor and blending. In this study, we investigated the thermophysical properties and molecular interactions of binary mixtures of MFF with short13 to medium-chain 2-alkanols (C₃–C₆), combining experimental measurements of density and viscosity with molecular dynamics (MD) simulations. Our findings reveal strong hydrogen-bond interactions between MFF’s aldehyde group and the hydroxyl groups of short-chain alcohols, leading to compact molecular packing, enhanced volatility, and improved combustion efficiency. Conversely, longer-chain alcohols introduce steric hindrance that disrupts hydrogen-bonding networks, increasing free volume and diffusivity, thereby influencing ignition delay and miscibility with conventional fuels. These results provide molecular19 level insights into customize viscosity, density, and volatility of renewable fuel blends, thereby enabling the design of advanced biofuels with improved engine compatibility and environmental performance.
