Equation of State for Water-Alcohol Mixtures over a Wide Range of State Variables

Coefficients of the three-parameter polynomial equation of states are determined from experimental data on the (p, rho, T, x) relationship for water-aliphatic alcohol (methanol, ethanol, and n-propanol) mixtures in the liquid and vapor phases and in the supercritical state: expansions of compressibility factor Z = p/RT rho (m) into series in powers of reduced density omega = rho(m)/rho(mcr); reduced temperature tau = T/T (cr) and composition x (as the mole fraction of alcohol), Z = p/RT rho(m) = 1 + Sigma(m)(i=1)Sigma(m)(j=0)Sigma(s)(k=0) a(ijk)omega(i)tau(-j)x(k); Z = p/RT rho(m) [1 + Sigma(m)(i=1)Sigma(m)(j=0)Sigma(s)(k=0) a(ijk)omega(i)tau(-j)x(k). The mean percentage errors of the calculated pressure values relative to the experimental values are 2% (liquid phase), 0.7% (vapor phase), and 0.5% (supercritical fluid).