Arrested-Flow Chromatographic Measurement of Gaseous Diffusion Coefficients

McCoy, Benjamin J.; Moffat, A.J.

doi:10.1080/00986448608911765

Cited by 19 publications

(12 citation statements)

References 6 publications

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“…The variance of each response pulse was determined from the width of the peak a t its half-height, which is 2.3548 times the square root of the variance (McCoy and Moffat, 1986). This method, valid for Gaussian curves, avoids difficulties of tailing and baseline drift that affect determination of variance by numerical integration.…”

Section: Resultsmentioning

confidence: 99%

“…As explained by McCoy and Moffat (1986), and by Knox and McLaren (t964), the spatial variance s of a pulse at the column exit is the superposition of the variance, so, due to the flow and reflow periods, and that due to diffusion during the stopped-flow period of duration t,,…”

Section: Theorymentioning

confidence: 96%

“…Maynard and Grushka (1975), in their review of gas chromatographic measurement of diffusion coefficients, discussed arrested-flow chro-matography, and Choudhary (1974) commented on the higher precision of the arrested-flow method. McCoy and Moffat (1986) revived the method recently to measure gas-pair diffusivities in open tubes.…”

Section: Introductionmentioning

confidence: 99%

“…Subtraction of variances for eluted bands, as in the determination of the slope of variances vs. delay time, will cancel convective dispersion and entrance and exit effects. From the slope of this line the effective diffusion coefficient for the column can be calculated (Knox and McLaren, 1964;McCoy and Moffat, 1986). The elimination of entrance and exit effects, and of convective dispersion and mass transfer, is an attractive feature of arrestedflow chromatographic measurement of packed-bed diffusivities.…”

Section: Introductionmentioning

confidence: 99%

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Intraparticle diffusion coefficients in packed columns: Measurement by arrested‐flow gas chromatography

1987

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Arrested-flow chromatography was used to determine intraparticle diffusivities of large-pore particles packed in columns. Particle and column tortuosity factors were determined for helium tracer in nitrogen carrier gas at 40°C and atmospheric pressure. Semiempirical modifications of Maxwell's, Burger's, Jeffrey's, and Rayleigh's relations for the composite diffusivity of spherical particles in a stationary medium are proposed for the effective composite diffusion coefficient for a packed bed of porous particles. The equations, modified to represent accurately the extraparticle void diffusion based on measurements for beds of nonporous particles, are used to evaluate intraparticle diff usivities from experimental data obtained by arrested-flow chromatography.

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Section: Resultsmentioning

confidence: 99%

Section: Theorymentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intraparticle diffusion coefficients in packed columns: Measurement by arrested‐flow gas chromatography

1987

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“…The cold trap filled with N 2 O 5 crystals was immersed in the bath of a cryostat (Lauda RLS 6) thermostatted at 235 to 250 K. Dried carrier gas was admitted through the cold trap. An upper limit of the partial pressure of N 2 O 5 in contact with the solid can be estimated with data from McDaniel et al (1988). This results in an upper limit of the mole fraction of about 0.1 to 0.6 %.…”

Section: Diffusion Of Dinitrogen Pentoxide (N 2 O 5 ) In Helium and Nmentioning

confidence: 97%

Technical note: Determination of binary gas-phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – arrested flow and twin tube method

et al. 2020

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Gas-phase diffusion is the first step for all heterogeneous reactions under atmospheric conditions. Knowledge of binary diffusion coefficients is important for the interpretation of laboratory studies regarding heterogeneous trace gas uptake and reactions. Only for stable, nonreactive and nonpolar gases do well-established models for the estimation of diffusion coefficients from viscosity data exist. Therefore, we have used two complementary methods for the measurement of binary diffusion coefficients in the temperature range of 200 to 300 K: the arrested flow method is best suited for unstable gases, and the twin tube method is best suited for stable but adsorbing trace gases. Both methods were validated by the measurement of the diffusion coefficients of methane and ethane in helium and air as well as nitric oxide in helium. Using the arrested flow method the diffusion coefficients of ozone in air, dinitrogen pentoxide and chlorine nitrate in helium, and nitrogen were measured. The twin tube method was used for the measurement of the diffusion coefficient of nitrogen dioxide and dinitrogen tetroxide in helium and nitrogen.

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Diffusion and adsorption in arrested‐flow chromatography

Smith

McCoy

1989

AIChE Journal

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Arrested-Flow Chromatographic Measurement of Gaseous Diffusion Coefficients

Cited by 19 publications

References 6 publications

Intraparticle diffusion coefficients in packed columns: Measurement by arrested‐flow gas chromatography

Intraparticle diffusion coefficients in packed columns: Measurement by arrested‐flow gas chromatography

Technical note: Determination of binary gas-phase diffusion coefficients of unstable and adsorbing atmospheric trace gases at low temperature – arrested flow and twin tube method

Diffusion and adsorption in arrested‐flow chromatography

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