5th Challenge Benchmark data

BENCHMARK DATA SUMMARY

 

James D. Olson, Richard E. Morrison, and Loren C. Wilson

The Dow Chemical Company

 

CHALLENGE:

 

For each of the following molecules:

 

1-ethylpropylamine, CAS# 616-24-0

3-methyl-1-pentanol, CAS# 589-35-5

 

Compute the:

 

1) 1-octanol-water partition coefficient (mole fraction units, assume neutral species) at 300 K and 101.325 kPa.

 

2) Infinite-dilution activity coefficient (mole fraction units, Lewis and Randall reference state) for the organic molecule dilute in water at 325 K and 13.5 kPa.

 

 

RECOMMENDED BENCHMARK VALUES:

 

1-ethylpropylamine, CAS# 616-24-0

 

1) 1-octanol-water partition coefficient (mole fraction units, assume neutral species) at 300 K and 101.325 kPa.

 

Kow(x) = xEPA(octanol-rich phase) / xEPA(water-rich phase) = 158

 

2) Infinite-dilution activity coefficient (mole fraction units, Lewis and Randall reference state) for the organic molecule dilute in water at 325 K and 13.5 kPa.

 

gamma∞ = 25.0

 

3-methyl-1-pentanol, CAS# 589-35-5

 

1) 1-octanol-water partition coefficient (mole fraction units, assume neutral species) at 300 K and 101.325 kPa.

 

Kow(x) = xMP(octanol-rich phase) / xMP(water-rich phase) = 312

 

2) Infinite-dilution activity coefficient (mole fraction units, Lewis and Randall reference state) for the organic molecule dilute in water at 325 K and 13.5 kPa.

 

gamma∞ = 245

 

 

DISCUSSION:

 

All four benchmark values were derived directly from experimental data measured for the simulation challenge at The Dow Chemical Company, Research and Development Department, Analytical Sciences.

 

1-Octanol-water partition coefficients were measured by equilibrating water and 1-octanol in a stirred sample-holder thermostated at 300 K. A small amount of the organic component was then added. After re-equilibration, samples were taken of each of the coexisting phases and analyzed by Karl Fischer titration and by capillary GC using a Helium pulsed-discharge detector (PDD). The mole fraction of the organic was then calculated for each phase and the ratio of the mole fractions gave Kow(x). The experimental setup was similar to that described by Christensen, et al. [1]; see also Reference [2] for a general description of liquid-liquid equilibria measurements.

 

Infinite-dilution activity coefficients were measured by dilute-solution ebulliometry; a known mass of water was charged to a twin-arm ebulliometer [3] and then brought to a boiling point of 325 K by using a manostat set to control the pressure at 13.5 kPa. Small increments of the organic component were then injected into the ebulliometer through a septum port and the change (delataT) in temperature recorded after each injection. The infinite-dilution temperature derivative, (dT/dx)P x => 0, was thus determined and the infinite-dilution activity coefficient calculated using the equations described in Reference [4].

 

 

LITERATURE REFERENCES:

 

[1] Christensen, S.P., F.A. Donate, T.C. Frank, R.J. LaTulip, and L.C. Wilson, J. Chem. Eng. Data 50, 869-877 (2005).

 

[2] Matouš, J., K. Řehák, and J. P. Novák, "Liquid-Liquid Equilibrium," Chapter 8 in Measurement of the Thermodynamic Properties of Multiple Phases, R.D Weir and Th.W. de Loos, Eds., Elsevier, Amsterdam, 2005.

 

[3] Olson, J.D., J. Chem. Eng. Data 26, 58-64 (1981).

 

[4] Olson, J.D., Fluid Phase Equilibria 52, 209-218 (1989).