In this study, second and third virial coefficients and the Joule-Thomson inversion curves for the binary mixtures of diethylamine (DEA) with 1-pentanol up to 1-nonanol were calculated regarding the Peng-Robinson-Stryjek-Vera (PRSV) equation. Experimental densities were used to calculate the adjustable parameters of the PRSV equation. The estimation of the thermodynamic factor for the binary systems from the COSMO-RS model shows that the considered mixtures exhibit a negative deviation from Raoult's Law. Besides, the diffusion coefficients for the binary mixtures in the whole composition range were determined regarding experimental viscosities. The results were analyzed to gain information about the liquid structure in the binary mixtures. It has been shown that intermolecular forces between DEA and 1-alkanol, which changes with the alcohol chain length, have a significant impact on the above-mentioned parameters. The investigation has shown that increasing the alcohol chain length reinforces the strength of intermolecular interactions
