Experimental Determination and Theoretical Modeling of Diethyl Carbonate +1-Butanol Binary Mixture

This work reports the vapor–liquid equilibria (VLE), liquid viscosity, and surface tension of a potential biofuel mixture formed by diethyl carbonate and 1-butanol. VLE measurements are performed at 50.00, 75.00, and 94.00 kPa, revealing a minimum-boiling azeotrope. The measured VLE data passed the point–point Fredenlund test and are well-correlated using the ϕ−γ approach, where the Wilson model displays the most accurate model for the liquid phase. This model is also incorporated into the Peng–Robinson Stryjek-Vera EoS using the MHV mixing rule to predict VLE data and extend their application over a broad pressure range. The liquid dynamic viscosity is measured at 298.15 K, exhibiting a negative deviation from linear behavior, decreasing as the mole fraction of diethyl carbonate increases. This behavior is predicted by the proposed extension of the scaling viscosity theory based on the EoSs used. The surface tension at 298.15 K showed a positive deviation and exhibited a maximum anisotropy point. The latter results are successfully modeled using the Chunxi model coupled to the reported Wilson model, allowing for the calculation of the relative Gibbs adsorption. The findings provide valuable information to advance the validation of this mixture as a potential biofuel or bio-oxygenate additive for fuels.