Friday, November 21, 2008: 10:45 AM-1:15 PM
Room 102-B (Pennsylvania Convention Center) 

10:45 - 11:00
Introduction to the IFPSC
J. Moore

11:00 - 11:20
The Problem and Benchmark Data
J. Olson

11:20 - 11:40
Entry 1
A. Klamt

11:40 - 12:00
Entry 2
R. Elliott

12:00 - 12:20
Entry 3
C.-M. Hsieh and S.-T. Lin

12:20 - 12:40
Entry 4
J. Moore for H. Sun

12:40 - 12:50
Announcement of Champions

12:50 - 01:15
Discussion and Feedback

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).

Prediction of 1-Octanol-Water Partition and Infinite-Dilution Activity Coefficients

Objective:

The objective of this Challenge of the IFPSC is to test the ability of computer modeling (any method) to predict 1-Octanol-Water Partition (ko/w) and Infinite-Dilution Activity Coefficients (gam-inf). Prediction of 1-Octanol-Water Partition Coefficients (which, admittedly, has been widely studied by non-molecular simulation computational methods) is viewed as a stepping stone to a more difficult problem, such as a case where a third component is present at a high enough level to influence the mutual solubilities of the other two.

This is a proposal for the 5th Industrial Fluid Properties Simulation Challenge problem. Please send you feedback and sugestions to ifpsc@fluidproperties.org by February 15, 2008.

Prediction of 1-Octanol-Water Partition and Infinite-Dilution Activity Coefficients

Objective:

The objective of this Challenge of the IFPSC is to test the ability of computer modeling (any method) to predict 1-Octanol-Water Partition (ko/w) and Infinite-Dilution Activity Coefficients (gam-inf).

Background:

The culmination of the 4th Industrial Fluid Properties Simulation Challenge occurred at a session on November 8 at the AIChE annual meeting in Salt Lake City, Utah. Announced in San Francisco in November of 2006, the IFPSC challenged entrants to calculate a wide range of thermodynamic and transport properties for new molecular models of ethylene oxide at 375 K. Five teams accepted the challenge and were judged based on the comparison of the properties of their new models to a set of benchmark data. Participants were honored at the AIChE session with plaques and cash prizes and gave presentations describing their work.

These days it seems that molecular simulation papers are appearing in almost every scientific journal, and the documentation of these simulation methods in not always of consistently high quality. Therefore, the IFPSC wants to create a checklist of sorts for authors to use when writing papers and for reviewers to use when evaluating papers to help improve the overall quality of the scientific literature in this field. At the IFPSC workshop at 3M during the fall of 2006, Wilfred van Gunsteren and Ray Mountain developed a first draft of such criteria given below.

We invite you to review these criteria and make comments to improve them. What needs to be added? What is essential? What is only "nice-to-have?" etc.

The scoring spreadsheet for the 4th Industrial Fluid Properties Simulation Challenge (IFPSC) is now available: link

More information about the 4th Challenge is available here: link

Please note that there are some typos in the paper by Wielopolski and Smith describing the "round-robin" model used as part of the 4th simulation challenge.

On page 471, the oxygen charge should be -0.3216.

On page 472, the Lennard-Jones size paramter σ(O-O) is incorrectly labeled as a mixed interaction σ(O-C). It is actually the oxygen size parameter.

Introduction and Background

Researchers working in an industrial setting are commonly asked to predict a wide range of physical properties. A method that is able to predict a broad range of properties (especially properties that were not used in the original model parameterization) may be more valuable in this situation than a method that may provide more accurate results but only for one property or property type.

The primary objective of the Fourth Industrial Fluid Properties Simulation Challenge is to test the transferability of methods and force fields to a wide variety of properties for a given small molecule. There will be two categories of competition: 1) "molecular simulation" methods and 2) "other methods." A champion will be announced for each of the two categories.