1978/09/01 by J. C. McGowan · 1 voice · 2 citations
Chemical Engineering · Chemistry · Engineering · #Chemical Thermodynamics and Molecular Structure #Phase Equilibria and Thermodynamics #Thermodynamic properties of mixtures
paper · doi:10.1002/jctb.5700280902
openalex publication_date 1978/09/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
Abstract An equation which relates the volume term (V=M/ (ρL‐ρg)) of unassociated liquids to pressure P and temperature T has been obtained by the combination of (a) 03V(∂ I /∂ V ) P→0 =T x ‐T for the effect of temperature on V at low (atmospheric) pressure and (b) ‐ V(∂ P /∂ V ) T = P x V x / 6 /V 6 p→0 +9(P‐p) for the effect of pressure on volume at constant temperature. In the equations, p is the vapour pressure; pL the density of the liquid and pg the vapour density. Often pg can be neglected compared with pL and p is small compared with the large pressures required to affect the densities of liquids appreciably. There are three constants: Tx , Px , which equals 4.455 × 10 9 N m 2 , and Vx which can be calculated by the addition of atomic values for all the atoms in the molecule and subtraction of a value (6.56 × 10 6 m 3 mol 1 ) for each bond. When V approximates to M /ρ L , the molar volume, the equation can be integrated to give the work and heat of isothermal compression. The viscosity of a liquid is related to the work of compression and solubilities in a liquid to the work required to bring the solute to the compressibility of the liquid. Many relationships can be derived and can be used to estimate properties of unassociated liquids.