Densities of n-alkanes and their mixtures at elevated pressures

Abstract

Accurate density data for n-alkanes over a wide range of temperature and pressure have been used to test existing correlation and prediction methods. It is found that the most successful representation at temperatures up to 0.66 times the critical temperature and pressures up to 150 MPa is given by the Tait equation in the form (ρ−ρ0)/ρ=C log [(B + P)/(B + P0)], where subscript 0 refers to 0.101 MPa, with C equal to 0.2000, and [B+(Cn−6)], where Cn is the number of carbon atoms in the alkane chain, is a smooth function of reduced temperature. A simple extension of this method to mixtures gives an excellent prediction of densities at pressures up to 150 MPa over the same reduced temperature range.