The (1, 1.5, 3, 6) Wagner vapor pressure equation has gained acceptance in
a variety of applications, e.g. in various software packages designed to 's
imulate' chemical engineering processes. While this equation can fit vapor
pressure data over the entire temperature range including the vicinity of t
he critical point, indiscriminate use of this equation can lead to substant
ial extrapolation errors and erroneous enthalpies of vaporization. Several
examples of vapor pressure fits compare results obtained from the (1, 1.5,
3, 6) Wagner equation with other equations constrained to fit the lower and
higher pressure limits. (C) 2001 Elsevier Science B.V. All rights reserved
.