Compressed liquid densities (P, ¦Ñ, T) for the n-nonane, n-undecane, CO2+n-nonane and CO2+n-undecane binary mixtures were determinated using a vibrating tube densimeter at temperatures from 313 to 363 K and pressures up to 25 MPa. The experimental densities obtained were correlated with the Benedict-Webb-Rubin-Starling equation of state (BWRS EoS) [1] and with the five and six-parameter equations modified by Toscani-Swarcz (MTS) [2]. Statistical values to evaluate the different correlations were reported with an absolute average deviation lower than 0.02% for the three correlations. The density values calculated by the MTS equations of state agree within an AAD of 0.01% with data reported by the NIST for nonane and 0.07% with data reported by Manuel Garc¨ªa et al. [3], and Jiangning Wu et al. [4] for undecane. Excess molar volumes for the binary mixtures were obtained with the n-nonane and n-undecane densities calculated by the BWRS equation of state and CO2 densities calculated from the Span-Wagner EoS.

Keywords: n-nonane, n-undecane, density, alkanes, carbon dioxide, BWRS, correlation.

[1] Starling, K. E. Termo Data Refined for LPG, Part 1: Equation of State and Computer Prediction, Hydrocarbon Process.1971, 50, 101-104.

[2] Toscani, S.; Szwarc, H. Two Empirical equation of State for Liquids to Improve p, V, T Data Representation and Physical Meaning. J. Chem. Eng. Data, 2004, 50, 1030-1037.

[3] Excess Volumes of (n-Nonane + n-Undecane between 288.15 and 308.15 K Manuel Garc¨ªa, Carlos Rey, Vicente P. Villar, and Julio R. Rodr¨ªguez, 1988, American Chemical Society.

[4] Composition Dependence of Densities and excess molar volumes of mixing of C8-C15 n-Alkane binary liquid systems at 308.15 and 313.15 K; Jiangning Wu and Abdul-Fattah A. Asfour, 1990, 1991; Elsevier Science Publishers B.V