A Review of Vapor-Liquid and Liquid-Liquid Equilibrium Data for Systems Relevant to Biodiesel Production

Biodiesel production involves complex phase interactions governed by vapor–liquid (VLE) and liquid–liquid (LLE) equilibria relations, whose correct prediction is essential for upstream and downstream unit operations modeling. Despite the availability of experimental studies in literature, there is a lack of systematic reviews that consolidate and critically analyze this data. This work presents a comprehensive review of experimental VLE and LLE data for systems relevant to biodiesel production, including alcohols, esters, glycerol, water, fatty acids, and oils. A database comprising approximately 6500 experimental points was systematically compiled from the literature and subsequently analyzed in terms of experimental methodologies, temperature and pressure ranges, system composition, and thermodynamic modeling approaches, including activity coefficient models (e.g., NRTL, UNIQUAC) and predictive methods (e.g., UNIFAC). The dataset includes 3975 VLE and 2494 LLE experimental points, enabling a structured classification of the studies and the identification of trends and gaps in the literature, such as the limited availability of LLE data at low temperatures and the underrepresentation of complex systems. The resulting analysis may support the selection and application of thermodynamic models, as well as contribute to the acquisition of new data - particularly for those more complex and less explored systems - and the continuous development of biodiesel-related processes.