THE CRITICAL CONSTANTS OF NORMAL ALKANES FROM METHANE TO POLYETHYLENE .2. APPLICATION OF THE FLORY THEORY

This paper examines the latest recommendations by Ambrose (on behalf of IUPAC) for the critical constants of normal alkanes, with the primary goal of extrapolating to very large normal alkanes such as linear polyethylene. The Flory theory has been modified slightly and applied to the correlation of the critical constants. The theory treats all three critical constants on an internally-consistent basis, which is a clear theoretical advance relative to previous work. Inclusion of the chain-length variation in the critical properties of normal alkanes makes it possible to establish the limiting values for critical temperature, pressure, and density. These limiting values are more credible than those predicted by ''power'' or ''exponential'' laws, which lack theoretical foundation and may be unsuitable for extrapolation.