Critical Evaluation of Ethene Solubilities in Organic Solvents Containing Sulfur or Phosphorus for pressures less than 0.20 MPa
Seven research groups reported solubilities of ethene in organic sulfur or organic phosphorus compounds usually expressed as the Henry's constants. Particularly the data of Lenoir et al.1 were obtained using a chromatographic method at low gas partial pressures, leading to possible errors when the results were extrapolated to 0.1013 MPa pressure. For only four of the eleven solvents were the results reported for three or more temperatures. Thus, for most of the solvents the effect of temperature on the solubility could not be determined from the results available. The sulfur and phosphorus-containing solvents were mainly the organic esters of either sulfuric or phosphoric acids. The ethene solubilities in the high boiling phosphoric acid esters were of particular interest because five of these solvents belonged to a homologous series. Thus the effect of solvent molecular weight could be qualitatively observed.There is a data sheet describing the solubility of ethene in triphenylphosphine at pressures up to 0.595 MPa which, strictly speaking, should have appeared in a chapter all of its own.
The solubilities in individual solvents will now be considered.
Carbon Disulfide; CS2; [75-15-0]
The solubility of ethene in carbon disulfide was reported by Sahgal et al.2 for 298.15 K and a partial pressure of 0.1013 MPa. No comparable data are available in the literature.
This result is classified as tentative.
Sulfinylbismethane (dimethyl sulfoxide); C2H6SO; [67-68-5]
The solubility of ethene in sulfinylbismethane at 298.15 K and for a gas partial pressure of 101.3 kPa was reported by Brückl and Kim3 and also by Lenoir et al.1. The two solubilities differ by less than one percent.
These values are classified as tentative.
Sulfuric acid, diethyl ester (diethyl sulfate); C4H10O4S; [64-67-5]
Ethene solubilities in sulfuric acid, diethyl ester were reported for temperatures ranging from 273.15 K to 353.15 K and for a gas partial pressure of 101.3 kPa by Truchard et al.4. These data are entirely consistent and are well represented by the following equation:
log x1 = 479.73 (T/K)–1 – 3.5998(1)
Equation (1) is simpler than that of the authors, and it represents the data with an average deviation of 0.7% and a maximum deviation of 1.5% for the whole temperature range.
The results of Truchard et al.4 are classified as tentative.
Amidosulfurous acid, diethylmethyl ester (N,N-dimethylsulfonamide, methyl ester); C5H13NO2S; [21954-69-8]
Ethene solubilities of Makitra et al.5 in the sulfonamide solvent for pressures below atmospheric are available for temperatures ranging from 253.15 K to 333.15 K. Unfortunately these data appear to be quite inconsistent. Henry's law is not even approximately obeyed; for each temperature the solubility results cannot be extrapolated to zero solubility corresponding to a zero partial pressure of gas. At pressures below atmospheric it would be expected that Henry's law would be obeyed. Furthermore, there is a large degree of scattering of the data. Also, the solubilities at any one pressure (at 725 mm of mercury pressure for example) do not follow a regular function of temperature.
Phosphoric acid, trimethyl ester; C3H9O4P; [512-56-1]
Phosphoric acid, triethyl ester; C6H15O4P, [78-40-0]
Phosphoric acid, tripropyl ester; C9H21O4P; [513-08-06]
Phosphoric acid, tributyl ester; C12H27O4P; [126-73-8]
Phosphoric acid, tri (2-methylpropyl) ester; C12H27O4P; [126-71-6]
Solubilities of ethene in five esters of phosphoric acid were reported by Lenoir et al.1 for a temperature of 325.2 K (and for three temperatures for the tripropyl ester) as Henry's law constants. There is some doubt that these Henry's constants, by a chromatographic technique at low partial pressures of gas, are representative of the true value at 0.1013 MPa pressure. However, a check on the value obtained by Lenoir et al. For the tributyl ester is available from the results of Kosyakov et al.6 for that solvent. The latter researcheers reported results for temperatures ranging from 223.15 K to 313.15 K from which they determined Henry's constants. The results of both research groups appear consistent with one another, and were used to develop an equation for the temperature effect of solubility at a pressure of 0.1013 MPa for phosphoric acid, tributyl ester as follows:
log x1 = 568.32 (T/K)–1 – 3.4716(2)
The average, and maximum deviation of the data from Eq. (2) for this solvent is 0.5%, and 1.2%, respectively. Equation (2) was developed for a temperature range from 223.15 K to 325.15 K and extrapolation beyond this temperature range is not recommended.As part of the consistency check, Fig. 1 was constructed to indicate the effect on the solubilities of ethene of the solvent molecular weight for the phosphoric acid esters for the constant temperature of 325.2 K. Figure 1 indicates that there is a consistent increase in ethene solubility at a temperature of 325.2 K as the molecular wweight of the phosphoric acid ester is increased. Thus, Fig. 1 may have some value in extending solubility data to the many different esters of phosphoric acid.
The data of Lenoir et al.1 and of Kosyakov et al.6 are classified as tentative.
Hexamethylphosphoric triamide; C6H18N3OP; [680-31-9]
Two sources for the ethene solubility in hexamethylphosphoric acid triamide for a temperature of 298.2 K are available: BrĆckl and Kim3, and Lenoir et al.1, with values of 0.0159 mole fraction ethene, and 0.0189 mole fraction, respectively. The difference between these tow comparable results of 19% is clearly beyond any normal experimental error. Given the low pressure chromatographic method used by Lenoir et al.1, their value is rejected, and the value of BrĆ and Kim3 is classified as tentative.
Triphenylphosphine; C18H15P; [603-35-0]
Ethene solubilities at the three temperatures, 363.2 K, 378.2 K, and 393.2 K, for the three pressures, 0.491 MPa, 0.546 MPa and 0.595 MPa, respectively, were reported by Herman et al.7. There are insufficient data to check for consistency. A linear extrapolation to a pressure of 0.0054 at 378.2 K and 0.0049 at 393.2 K. The extrapolated results must be considered approximate only.
The original data are classified as tentative.