chapensk (version 0.4)

binary_diffusion: Binary gas phase diffusion coefficients of methane, ethane, propane and butane in helium and nitrogen; fluoromethane, difluoromethane and trifluoromethane in nitrogen measured by reverse-flow gas chromatography

Description

Reference data of binary diffusion coefficients for comparison with calculated diffusion coefficients. Diffusion coefficients were determined using a reversed-flow gas chromatography system.

Usage

data("binary_diffusion")

Format

A data frame with 91 observations on the following 6 variables.

doi

DOI of data source

bath_gas

Bath gas helium or nitrogen

gas

Diffusing species C2H6, C3H8, C4H10, CH2F2, CH3F, CH4, CHF3

T

Temperature in K

D

Diffusion coefficient in cm2/s

U_D

Uncertainty of diffusion coefficient in cm2/s

Details

The diffusion coefficient \(D\) as function of pressure in a narrow temperature range close to the reference temperature \(T_0\) is usually expressed as (Langenberg et al. 2020) $$D = D_0 \left(\frac{p_0}{p}\right)\left(\frac{T}{T_0}\right)^b$$ For the experimental data, the temperature coefficient \(b\) is obtained from the fit. For the calculated diffusion coefficients, the temperature coefficient is calculated by $$b = \left(\frac{\partial D}{\partial T}\right)_{T_0} \left(\frac{T_0}{D_0}\right).$$ The diffusion coefficients \(D_\mathrm{calc}\) are calculated using Gas-class. The deviation is calculated by $$\frac{D_\mathrm{exp} - D_\mathrm{calc}}{D_\mathrm{exp}}.$$

Gas	Bath gas	Experimental		Calculated		Deviation
		\(D_0\) / [cm2/s]	\(b\)	\(D_0\) / [cm2/s]	\(b\)	nitrogen
helium	0.605(3)	1.664(8)	0.620	1.68	-3%	argon
helium	0.630(2)	1.665(6)	0.640	1.68	-2%	methane
helium	0.575(3)	1.675(7)	0.597	1.68	-4%	ethane
helium	0.421(5)	1.68(2)	0.446	1.70	-6%	propane
helium	0.341(7)	1.67(2)	0.361	1.70	-7%	butane
helium	0.294(6)	1.65(2)	0.368	1.74	-32%	methane
nitrogen	0.201(2)	1.74(2)	0.186	1.83	7%	ethane
nitrogen	0.136(2)	1.70(2)	0.123	1.87	7%	propane
nitrogen	0.106(2)	1.72(3)	0.094	1.88	7%	butane
nitrogen	0.090(1)	1.72(2)	0.084	1.97	-8%

The values in brackets indicate the uncertainties (0.95 confidence level) of the fit parameters. With the exception of the diffusion of butane in helium, the calculated diffusion coefficients well resemble the measured diffusion coefficients within an error limit of < 10%. For larger non spherical molecules like butane in helium more advanced combining rules need to be applied (Li et al. 2023).

The experimental data for the diffusion coefficients of fluoromethanes can in turn be used to estimate the Lennard-Jones parameters for the Van der Waals interaction. The values for \(\sigma\) obtained are smaller than \(\sigma\) obtained from data of viscosity measurements (Shibasaki-Kitakawa et. al. 1995, Clifford et al. 1979).

Gas	\(D_0\)/ [cm2/s]	\(b\)	Viscosity		Diffusion
		\(\sigma\) / [Ao]	\(\varepsilon/k\) / [K]	\(\sigma\) / [Ao]	\(\varepsilon/k\) / [K]	fluoromethane
0.1576(7)	1.784(8)	--	--	3.5	174	difluoromethane
0.133(2)	1.76(2)	4.9	204	3.9	153	trifluoromethane
0.123(2)	1.73(2)	4.4	182	4.5	63

This is due to the fact that both molecules have a dipole moment. This is why the intermolecular interaction of polar molecules cannot be described in terms of the Lennard-Jones potential.

References

Clifford AA, Gray P, Scott AC. Viscosities of CFCl3, CF3Cl, CHFCl2, CHF2Cl and CHF3 from 373 to 570 K. J. Chem. Soc., Faraday Trans. 1, 1979;75:1752. tools:::Rd_expr_doi("10.1039/F19797501752")

Langenberg S, Carstens T, Hupperich D, Schweighoefer S, Schurath U. 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. Atmospheric Chemistry and Physics 2020;20:366982. tools:::Rd_expr_doi("10.5194/acp-20-3669-2020").

Li Y, Gui Y, You X. On the binary diffusion coefficients of n-alkanes in He/N2. Combustion and Flame 2023;257:112795. tools:::Rd_expr_doi("10.1016/j.combustflame.2023.112795").

Shibasaki-Kitakawa N, Takahashi M, Yokoyama C, Takahashi S. Gas Viscosity of Difluoromethane from 298.15 to 423.15 K and up to 10 MPa J. Chem. Eng. Data 1995; 40:900-902 tools:::Rd_expr_doi("10.1021/je00020a036")

Examples

# binary diffusion data of nitrogen in bath gas helium
nitrogen_in_helium <- subset(binary_diffusion,(gas=="nitrogen" & bath_gas=="helium"))
print(nitrogen_in_helium)