ASTM D3827 Test Method for Estimation of Solubility of Gases in Petroleum and Other Organic Liquids
6. Procedure
6.1 Obtain the value of d1 for the liquid by the appropriate one of the following options:
6.1.1 If the liquid is a nonhydrocarbon, obtain d1 from Table 2. If it is not listed there, and the structure is known, calculate d1 by the method of Fedors.

6.1.2 If the liquid is refined petroleum or a synthetic hydrocarbon, determine r by Test Method D1218 or equivalent. If r is 0.885 g/mL or less, calculate d1 as follows:
δ1 = 12.03ρ + 7.36

6.1.3 If the liquid is refined petroleum or a synthetic hydrocarbon with ρ = 0.886 g/mL or more, or a nonhydrocarbon of unknown structure, determine nD by Test Method D1218, and calculate as follows:
δ1 = 8.63nD2 + 0.96

NOTE 1 - Values of δd1 from Table 2 or ρ are accurate to +/-0.2 unit, but those from nD may be in error by as much as +/-1.0 unit.

6.1.4 For mixtures of liquids with solubility parameters δa, Φb... δi in volume fractions Φa, b... Φi, calculate δ1 as follows:
δ1 = Φaδa + Φbδb ... + Φiδi

6.2 Obtain the value of δ2 from Table 1.

6.3 Calculate the Ostwald coefficient for a lubricant as follows:
L = exp[(0.0395(δ1 - δ2)2 - 2.66)(1 - 273/T) - 0.303δ1 - 0.0241(17.60 - δ2)2 + 5.731]

6.4 Calculate the Ostwald coefficient for a distillate fuel or halogenated solvent as in 6.3, then multiply by the fuel factor from Table 1.

6.5 Calculate the Bunsen coefficient as follows:
B = 2697(p - pv)L/T

NOTE 2 - For most lubricants, pv is less than 10 % of p and can be neglected. For fuels, solvents or oils contaminated with solvents and fuels, or at very high temperatures, pv is important.

6.6 For mixtures of gases, calculate the individual Ostwald coefficients as in 6.3, calculate a Bunsen coefficient for each and add them together.

6.7 For hydrocarbon oils, obtain rt as follows:
ρt = ρ(1 - 0.000595(T - 288.2)/ρ1.21)

NOTE 3 - The constants 0.000595 and 1.21 are an empirical approximation of the calculations involved in Guide D1250.

6.8 For nonhydrocarbon liquids, obtain ρt by one of the following methods, listed in decreasing order of preference:
6.8.1 Determine it directly, using Test Method D1298 or equivalent.

6.8.2 Obtain suitable data from the supplier of the liquids.

6.8.3 Obtain r by one of the above, and adjust it as follows, using dd/dT from Table 2:
ρt = ρ - (T - 288.2)dr/dT

6.8.4 Obtain both r and dr/dT from Table 2 and combine as in 6.8.3.

6.9 Obtain M2 from Table 1, and calculate the solubility in mg/kg:
G = 44.6BM2/rt

NOTE 4 - The equation in 6.9 is based on the assumption that the liquid in definitions 3.1.1, 3.1.2, and 3.1.3 has the same volume and density as the oil. That is a good approximation, except for gases more soluble than CH4. Furthermore, the laborious corrections required to render this more rigorous are not justified in light of the precision shown in Section 7.

6.10 Obtain the value of M1 by the appropriate one of the following options:
6.10.1 For synthetic nonhydrocarbons, locate in Table 2 or calculate directly.

6.10.2 For refined petroleum or synthetic hydrocarbons, estimate M1 by Test Method D2502.

6.10.3 For nonhydrocarbons of unknown structure, determine M1 by Test Method D2503. Despite the limitations implied in its scope, that method will serve this purpose.

6.11 Calculate the solubility as mole fraction as follows:
X = 10(-6) GM1/M2

6.12 Calculate the Henry's law constant as follows:
H = (p - pv)/X