Vapor and Sublimation Pressures of Three Normal Alkanes: C₂₀, C₂₄, and C₂₈

Abstract

Vapor and sublimation pressures of three n-alkanes C20, C24, and C28 have been determined using a modified gas saturation method. The obtained pressure values range from 10−5 Pa to 5.5 Pa. From the temperature dependence of the vapor pressures, the molar enthalpies of vaporization and sublimation at the mean temperature of the experimental range were derived from the Clausius−Clapeyron equation. From these results, the standard enthalpies of vaporization and sublimation at T = 298.15 K were calculated.

The Use of Antioxidants to Improve Vapor Pressure Measurements on Compounds with Oxidative Instability: Methyl Oleate with tert-Butylhydroquinone

“…The goal of this work was to develop procedures for vapor pressure ( p sat ) measurements with the gas saturation method on compounds with oxidative instability. The gas saturation method, which is also known as the transpiration method, is a commonly used measurement technique for the determination of p sat < 1 kPa. − The basis of this method is the saturation of an inert carrier gas with vapor from a condensed phase. From measurements of the amount of vapor solute and the amount of carrier gas, one can calculate p sat .…”

Thermophysical properties of polyol ester lubricants

“…The vapor pressures (psat) of POE5 and n-octacosane (C28H58, a control compound) were measured by the gas saturation method [7][8][9][10][11][12][13][14][15] at temperatures of 353.05 K and 362.93 K. The basis of the gas saturation method is the saturation of an inert carrier gas with vapor from a condensed phase.…”

Experimental vapour pressures of eight n-alkanes (C17, C18, C20, C22, C24, C26, C28 and C31) measured at ambient temperatures

“…There are, however, well established experimental methods that provide good results at low pressures; for example the transpiration (Verevkin et al, 2000) and the Knudsen effusion techniques M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 4 (Dekruif and Vanginkel, 1077;Hallquist et al, 1997). Vapour pressure measurements have been conducted at ambient temperatures for few organic compounds using different techniques based upon the rate of evaporation of a compound under well controlled conditions (Razzouk et al, 2009;Cappa et al, 2007;Koponen et al, 2007). The majority of studies however, estimate p from experiments performed at high temperatures (Sawaya et al, 2006;O'Meara et al, and refs within), with subsequent extrapolation to ambient temperatures.…”

“…The majority of literature values of vapour pressure of the n-alkanes were estimated from extrapolation of vapour pressures measured at higher temperatures (Chirico et al, 1989;Morgan and Kobayashi, 1994;Sawaya et al, 2006;Razzouk et al 2009). Very few studies have measured vapour pressures of n-alkanes at 298 K (Chickos and Hanshaw, 2004a;Chickos and Hanshaw, 2004b) and more recently extended measurements (and estimations) for n-alkanes up to n-C 92 (Chickos et al, 2009).…”