Phase Behavior and Thermodynamic Modelling for Biofuel Relevant Oxygenated Mixtures: 3-Pentanol + Propionic acid and 3-Pentanol + 2-Propanol at 101.3 kPa

In this study, the VLE of the binary systems containing 3-pentanol + propionic acid and 2-propanol + 3-pentanol were measured at 101.3 kPa using an Othmer-type ebulliometer. The measured temperatures of the binary mixture ranged from 388.59 K to 414.25 K and 355.19 K to 388.49 K for the 3-pentanol + propionic acid and 2-propanol + 3-pentanol systems, respectively. The results showed that the relative volatilities (α12) were greater than 1, and no azeotrope was found in the binary systems studied. The Non-Random Two-Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models, in combination with the Hayden O’Connell (HOC) model, accurately correlated the experimental VLE data for 3-pentanol + propionic acid. The experimental VLE of the 2-propanol + 3-pentanol system was well correlated by the NRTL and UNIQUAC models. The average absolute percentage deviations (AAPDs) of temperatures and equilibrium compositions were less than 1% for all systems and models used. The consistency of the experimental VLE data was satisfactorily ascertained using the Herington test method. The Universal Functional Activity Coefficient (UNIFAC) and UNIFAC-HOC models were also applied in this study and compared with the experimental VLE data.