Critical evaluation of the solubility of ethene at a partial pressure not greater than 101.3 kPa in solvents, other than alcohols, containing carbon, oxygen and hydrogen.

It is often helpful to compare experimental values of mole fraction solubility x₁, of a gas at a particular temperature with reference values from the Raoult's law equation

x₁ = p₁/p_o

where p_o is the vapour pressure of liquefied gas at the temperature in question. The variation with temperature of p₁/p_o provides a reference line for comparison of solubility. The critical temperature of ethene is 282.4 K but it is convenient to extrapolate the vapour pressure of ethene to temperatures above the critical temperature to calculate a reference line and hence facilitate qualitative comparison of experimental solubility. Mole fraction solubility in most solvents containing oxygen fall below the reference line and are low compared with solubility in straight chain hydrocarbons.

2-Propanone; C₃H₆O; [67-64-1]

Solubility in 2-propanone has been measured by Horiuti¹, Hannaert et al.², Leites and Ivanovskii³, and by McDaniel⁴. McDaniel's values for a partial pressure of 101.3 kPa fall appreciably below those given by Horiuti and can be disregarded because other measurements by McDaniel have been found to be significantly lower than measurements carried out more recently. Solubility values calculated from equations given by Hannaert for 283.15 K and 293.15 K are, respectively, about 18% and 14% above values given by Horiuti. Horiuti's data for the temperature range of 273.15 to 313.15 K is likely to be the more reliable. A measurement carried out by this author on other systems is often in close agreement with more recent precision measurements. Horiuti's data can be fitted to the equation:
ln x₁ = - 1.3472 + 795.05/(T/K) - 1.0247 ln(T/K)
where x₁ is the mole fraction solubility at p₁ = 101.3 kPa standard deviation in values of x₁ = 2.0 × 10^-5 temperature range 273 K to 313 K This equation may be accepted on a tentative basis.

The following equation is based upon Horiuti's measurements from 273.15 K to 313.15 K, on Flannaert's measurements from 243.15 K to 293.15 K and on the single value at 243.15 K given by Leites and Ivanovskii.
ln x₁ = -8.5070 + 1195.3/(T/K)
standard deviation in values of x₁ = 8.5 × 10^-4 temperature range 243 K to 313 K.
This equation is recommended on a tentative basis for temperatures below 273 K.

Methyl acetate; C₃H₆O₂ [79-20-9]

Horiuti¹ also measured solubility in methyl acetate. Mole fraction solubility at a partial pressure of 101.3 kPa fit the equation:
ln x₁ = 3.2620 + 569.63/(T/K) - 1.6935 ln(T/K)
standard deviation in values of x₁ = 3.4 × 10^-5 temperature range 273 K to 313 K.
Horiuti's data for methyl acetate is classified as tentative.

Cyclopentanone; C₅H₈0; [120-92-3]
Cyclohexanone; C₆H₁₀0; [108-94-1]
2-Methylcyclohexanone; C₇H₁₂0; [583-60-8]
2, 6-Dimethylcyclohexanone; C₈H₁₄0; [2816-57-1]

Gallardo and co-workers have measured solubility in cyclic ketones^5-9 at a partial pressure of ethene of 101.3 kPa in the temperature 273.15 K to 303.15 K. Mole fraction solubility at the same temperature in these solvents are in the order 2,6-dimethylcyclohexanone > 2-methyl-cyclohexanone > cycloheptanone > cyclohexanone > cyclopentanone. Sets of measurements are consistent with each other (see Fig.1).) and all fall below the reference line based on Raoult's law in this temperature range.

Solubility at a partial pressure of gas of 101.3 kPa may be fitted to the following equations derived by the evaluator. These give slightly better fit than equations given by the authors.

2,6-dimethylcyclohexanone
ln x₁ = - 8.5574 + 1294.9/(T/K)
standard deviation in values of x₁ = 3.4 × 10^-5

2-methylcyclohexanone
ln x₁ = 41.885 - 980.94/(T/K) - 7.5339 ln(T/K)
standard deviation in values of x₁ = 5.9 × 10^-5

cycloheptanone
ln x₁ = -22.106 + 1764.3/(T/K) + 2.0544 ln(T/K)
standard deviation in values of x₁ = 2.4 × 10^-5

cyclohexanone
ln x₁ = 35.451 - 773.66/(T/K) - 6.5627 ln(T/K)
standard deviation in values of x₁ = 2.9 × 10^-5 cyclopentanone
In x₁ = 25.679 - 337.58/(T/K) - 5.1162 ln(T/K)
standard deviation in values of x₁ = 1.4 × 10^-5

These equations may be accepted on a tentative basis for the temperature range 273.15 K to 303.15 K.

4-Methyl-1,3-dioxolan-2-one (propylene carbonate); C₄H₆O₃ [108-32-71]

Henry's constants for dissolution of ethene in 4-methyl-1,3-dioxolan-2-one was measured by a chromatographic method at 298.2 K to 343.2 K by Lenoir et al.¹⁰. Mole fraction solubility at 298.2 K and a partial pressure of 101.3 kPa, calculated on the assumption of a linear variation of mole fraction solubility with partial pressure, is 0.00521 compared with 0.00421 from measurements by Briickl and Kim¹¹. Solubility reported by Lenoir et al. for some of the other systems which they have studied are high compared with measurements by other groups. This is probably due to limitations of the chromatographic method. Further measurements on this system are required.

1,2-Epoxyhexane; C₆H₁₂O; [592-90-5]

Mole fraction solubility measured by Gibanel et al.¹² at a partial pressure of 101.3 kPa in 1,2-epoxyhexane fall in between solubility in 2-methylcyclohexanone and 2,6-dimethylcyclohexanone. The data may be fitted to the equation
ln x₁ = -50.928 + 3025.0/(T/K) + 6.4117 ln(T/K)
standard deviation in values of x₁ = 2.9 × 10^-5 temp. range 273 K to 303 K

This equation may be accepted on a tentative basis.

1,4-Dioxane; C₄H₈O₂ [123-91-1]

Solubility in the cyclic diether, 1,4-dioxane is low compared with that in cyclic ketones. Solubility at a partial pressure of ethene of 101.3 kPa reported by Gallardo et al.¹³ for the temperature range 285.15 K to 303.15 K fit the equation
ln x₁ = -1.2404 + 763.88/(T/K) - 1.0499 ln(T/K)
standard deviation in values of x₁ = 1.7 × 10^-5
This equation fits the data better than the one given by the authors and may be accepted on a tentative basis.

1, 1'-[Methylenebis(oxy)]-bisethane; C₅H₁₂O₂

The mole fraction solubility reported by Lizano et al.¹⁴ at a partial pressure of 101.3 kPa in the acetal, 1,1'-[methylenebis(oxy)]-bisethane, is higher than that in the cyclic ketones (see Fig. 1). Values lie above the reference line based upon the Raoult's law equation. The data may be fitted to the equation
ln x₁ = -17.138 + 1927.7/(T/K) + 1.1882 ln(T/K)
standard deviation in values of = 2.6 × 10^-5 temp. range 263 K to 303 K

This equation may be accepted on a tentative basis.