A Gas Saturation Apparatus for Very Low Vapor or Sublimation Pressure Measurements (10-3 Pa):  Vapor−Liquid Equilibria of n-Alkanes (n-C10, n-C24, n-C28)

Mokbel, Ilham; Razzouk, Antonio; Msakni, and Nizar; José, Jacques

doi:10.1021/je7001122

Cited by 24 publications

(27 citation statements)

References 31 publications

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“…The use of a very small saturator, a key design element that was recently piloted in our group, distinguishes DVME from previously reported gas-saturation methods. ,,,,,,, An important benefit of the small saturator is that the temperature gradients are minimized. This is important because, with larger saturators, temperature gradients can dominate measurement uncertainty for p 2 sat and effectively limit the useable temperature range …”

Section: Resultsmentioning

confidence: 99%

“…The most common measurement strategies for compounds with low p sat are static methods, effusion methods, and gas saturation (sometimes called “transpiration”) methods. ,− Of those, gas saturation methods have an advantage with compounds of lower purity or poorer stability. ,, In general, for gas saturation methods, an inert carrier gas flows through a “saturator,” which is a temperature-controlled vessel that contains the condensed phase of the compound being measured. The carrier gas becomes saturated with the vapor of the condensed phase before flowing into a vapor trap, which strips the vapor from the carrier gas.…”

Section: Introductionmentioning

confidence: 99%

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Rapid Vapor-Collection Method for Vapor Pressure Measurements of Low-Volatility Compounds

et al. 2020

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Dynamic vapor microextraction (DVME) is a new method that enables rapid vapor pressure measurements on large molecules with state-of-the-art measurement uncertainty for vapor pressures near 1 Pa. Four key features of DVME that allow for the rapid collection of vapor samples under thermodynamic conditions are (1) the use of a miniature vaporequilibration vessel (the "saturator") to minimize the temperature gradients and internal volume, (2) the use of a capillary vapor trap to minimize the internal volume, (3) the use of helium carrier gas to minimize nonideal mixture behavior, and (4) the direct measurement of pressure inside the saturator to accurately account for overpressure caused by viscous flow. The performance of DVME was validated with vapor pressure measurements of n-eicosane (C 20 H 42 ) at temperatures from 344 to 374 K. A thorough uncertainty analysis indicated a relative standard uncertainty of 2.03−2.82% for measurements in this temperature range. The measurements were compared to a reference correlation for the vapor pressures of n-alkanes; the deviation of the measurements from the correlation was ≤2.85%. The enthalpy of vaporization of n-eicosane at 359.0 K was calculated to be Δ vap H = 91.27 ± 0.28 kJ/mol compared to Δ vap H(corr) = 91.44 kJ/mol for the reference correlation. Total measurement periods as short as 15 min (3 min of thermal equilibration plus 12 min of carrier gas flow) were shown to be sufficient for high-quality vapor pressure measurements at 364 K.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rapid Vapor-Collection Method for Vapor Pressure Measurements of Low-Volatility Compounds

et al. 2020

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“…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 .…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2016

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The vapor pressure (p sat) of methyl oleate was measured with and without the addition of 0.2 mass % of the antioxidant stabilizer tert-butylhydroquinone (TBHQ). The measurements were made by the gas saturation method with a temperature range of 303.15–343.15 K. In the absence of TBHQ, oxidative decomposition severely compromised the measurements, as evidenced by dramatic decreases in the measured p sat for repeat measurements at 323.15 K. When combined with a room-temperature N2 flush of the apparatus, the addition of 0.2 mass % TBHQ limited the decomposition to insignificant levels and resulted in repeatable measurements of p sat. Simultaneous measurements on the control sample n-eicosane (C20H42) yielded values of p sat that were in excellent agreement with reference correlations.

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“…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.…”

Section: Vapor Pressure Of Poe5mentioning

confidence: 99%

Thermophysical properties of polyol ester lubricants

Bruno¹,

Fortin²,

Huber³

et al. 2019

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This report summarizes the results of work performed for the Naval Air Warfare Center Aircraft Division by the National Institute of Standards and Technology (NIST), Applied Chemicals and Materials Division on the properties of polyol ester lubricants under interagency agreement number N0042115IP00008. The work includes purity analysis and assessment, decomposition studies, experimental measurements on density, isobaric heat capacity, speed of sound, vapor pressure, viscosity, thermal conductivity, and distillation curve measurements. Models were developed for the thermodynamic properties, viscosity, and thermal conductivity that represent these properties to nearly within their experimental uncertainty for three pure polyol ester base fluids (pentaerythritol tetrapentanoate (POE5), pentaerythritol tetraheptanoate (POE7), pentaerythritol tetranonanoate (POE9), and a fully qualified lubricant meeting military specification MIL-PRF-23699.

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A Gas Saturation Apparatus for Very Low Vapor or Sublimation Pressure Measurements (10^-3 Pa): Vapor−Liquid Equilibria of n-Alkanes (n-C₁₀, n-C₂₄, n-C₂₈)

Cited by 24 publications

References 31 publications

Rapid Vapor-Collection Method for Vapor Pressure Measurements of Low-Volatility Compounds

Rapid Vapor-Collection Method for Vapor Pressure Measurements of Low-Volatility Compounds

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

Thermophysical properties of polyol ester lubricants

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