Densities (ρ) and sound velocities (u) of the pure liquids obtained from different biomass conversion: furfural, furfuryl alcohol, toluene, and ethanol were measured at temperature range from 283.15K to 313.15K at 10K interval using a vibrating tube densimeter and sound velocity analyzer (Anton Paar DSA 5000M). Besides that, the densities and sound velocities of the binary systems {furfural or furfuryl alcohol (1)+toluene (2)} and {furfuryl alcohol (1)+ethanol (2)} in the above mentioned conditions and over the entire range of composition were also measured. From these physicochemical data, thermodynamic excess functions, such as excess molar volumes, VmE, isentropic compressibility, κ s , and deviation in isentropic compressibility, Δκ s , were calculated and correlated using the Redlich–Kister polynomial equation. The sign and magnitude of these quantities have been interpreted in term of molecular interactions between components of molecules.