Vapor Pressure Slide Rule

The Antoine Equation for Vapor-pressure Data.

“…log P (mm.) = 6.8723 -1078.4/(t + 234.1) (35) fits the data to well within the reported accuracy up to TR = 0.83 (about 117°C. ), but gives increasingly larger errors from this temperature to the critical.…”

Behavior of Plasticizers in Vinyl Chloride-Acetate Resins

“…the rate of loss will be doubled. For calculations in practice it may be preferable to use a slightly different form of Equation 2: W2 Wi 4 ~Tt) t\d% (3) where K = eb = 1.10 or 10°•042 Although a rise of approximately 13°C, doubles the vapor pressure of high boiling esters, a rise of only 7°to 8°C. suffices to double the rate of volatile loss of plasticizer from these films.…”

“…Poor compatibility and chemical instability of the plasticizer will, of course, operate to increase the amount of loss. For a comprehensive treatment of the dependence of vapor pressure on temperature the reader is referred to the work of Miles (3).…”

Estimating Vapor Pressures—a Comparison of Equations

“…of the Miles-Unwin equation(4,23,50) is: MM log Patm = A -^(40) where in terms of the input data: = ~z Ylj/R A = B/I»U (4°A) 3nd (4°B) Three variants of this equation, MM1, MM2, and MM3, were based on different choices of 1/AZ, Equations 34, 35, and 37, respectively, with the last chosen to give the best compromise fit at low pressures.antoine equation.The nonreduced form of the Antoine equation(47,48) is:…”