Measurement and modelling of solid-liquid equilibria, density and viscosity of fatty acid methyl or ethyl esters

Abstract

The solid-liquid equilibria (SLE), densities and viscosities of few selective methyl or ethyl esters, required for the reformulation of biodiesel fuel, have been studied at different temperatures and at atmospheric pressure 0.1 MPa. The SLE, density (ρ) and kinematic viscosity (ν) of ethyl decanoate (1) + methyl laurate (2) or methyl myristate (2) binary systems were measured at different temperatures from 298.15 K to 318.15 K and were further used to derive other thermodynamic properties like excess molar volume (VmE) and deviations in dynamic viscosity (Δη). The experimental SLE data showed single eutectic point and correlated well with common nonrandom two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) equations. The kinematic viscosity (ν) data were best correlated with McAllister equation and deviations in dynamic viscosity (Δη) were described by Singh approach whereas excess molar volume (VmE) data were predicted well with Prigogine–Flory–Patterson (PFP) theory for the composition x1 ≤ 0.5634. The derived thermodynamic properties were also correlated with Redlich-Kister polynomial.