Critical constants and acentric factors for long-chain alkanes suitable for corresponding states applications. A critical review

Abstract

Several methods for the estimation of the critical temperature T c, the critical pressure P c, and the acentric factor ω for long-chain n-alkanes are reviewed and evaluated for the prediction of vapor pressures using Corresponding States (CS) methods, like the Lee-Kesler equation and the cubic equations of state. Most reliable and recent literature methods proposed for the estimation of the acentric factor of heavy alkanes yield similar values and the emphasis is, thus, given to the determination of the best sets of T c and P c. Various extrapolation schemes proposed for this purpose and several general group-contribution methods were investigated in this work. The correlations proposed by K. Magoulas and D. Tassios, Thermophysical properties of n-alkanes from C 1 to C 20 and their prediction for higher ones, Fluid Phase Equilibria, 56 (1990) 119–140; A.S. Teja, R.J. Lee, D.J. Rosenthal, M. Anselme, Correlation of the critical properties of alkanes and alkanols, Fluid Phase Equilibria, 56 (1990) 153–169; W. Hu, J. Lovland and P. Vonka, Generalized vapor pressure equations for n-alkanes, 1-alkenes, and 1-alkanols, Presented at the 11th Int. Congress of Chemical Engineering, Chemical Equipment Design and Automation CHISA '93, 29 August-3 September 1993; and the recent group-contribution method by L. Constantinou and R. Gani, New Group Contribution Method for Estimating Properties of Pure Compounds, AIChE J., 40 (10) (1994) 1697–1710; provide the most promising results.