Methods for Calculating the Critical Constants of Hydrocarbons (Using the n-Alkane Series as an Example)

This paper presents the calculation method allowing one to obtain the matched magnitudes of critical parameters of hydrocarbon gases with an accuracy comparable to the errors of the experimental methods. The ratios obtained allow an assessment of the values of the critical temperature, critical pressure, critical volume, acentric factor, and compressibility in the homologous series of alkanes up to C100. The critical parameters for alkanes 4 < nC < 40 calculated using formulas presented in the article demonstrated good consistency with the experimental data. The proposed values of critical constants for normal alkanes can be used to calculate the physiochemical properties of the compounds, while the calculation methods can be used to determine the critical constants of hydrocarbon components of other homologous series.