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The third industrial fluid properties simulation challenge was held from March to September 2006. As in the previous two events contestants were challenged to predict specific, industrially relevant, properties of fluid systems. Their efforts were judged based on the agreement of the predicted values with previously unpublished experimental data (provided by researchers at ExxonMobil and DuPont). The focus of this contest was on the transferability of modeling methods-the ability to predict properties for materials that are chemically different, or at different state points, to those used in model parameterization and validation. Nine groups attempted to compute bubble point pressures for mixtures of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) and ethanol at 343 K, given data for mixtures at 283 K, and given the pure component vapor pressures. They used a range of different techniques including statistical mechanical and molecular simulations-based approaches. Four of the groups were recognized for providing predictions that were significantly more accurate than would be obtained by extrapolation using the NRTL model (the standard engineering approach). Three groups undertook the more challenging "molecular transferability" problem, attempting to predict shear viscosities at two different state points for a range of diols and triols for which little experimental data was available.

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a b s t r a c tThe primary goal of the fourth industrial fluid properties simulation challenge was to test the transferability of molecular simulation methods and intermolecular potentials (force fields) when applied to a wide variety of physical properties for a given industrially relevant small molecule. Force field parameters are often developed for, tested with, and applied to a relatively limited range property types. Methods that are able to predict a broad range of properties may be more useful for practical application in an industrial setting. To address this primary goal, entrants were challenged to develop new intermolecular potential models for ethylene oxide (EO) and to us they predict a variety of physical properties. The predictions were judged by comparison to a set of benchmark values established based on peer-reviewed scientific literature and highly regarded property databases, and the results were generally excellent. A secondary objective was to assess the variability of those property predictions when performed by different researchers using the same force field (a "round-robin" experiment). To address this goal, entrants were challenged to calculate the same set of properties for a specific EO potential model from the literature, and good consistency was found between the predictions of most of the entrants.

Theoretical chemistryTheoretical chemistry Z 0350The First Industrial Fluid Properties Simulation Challenge -[50 refs.]. -(CASE, F.; CHAKA, A.; FRIEND, D. G.; FRURIP, D.; GOLAB, J.; JOHNSON, R.; MOORE, J.; MOUNTAIN, R. D.; OLSON, J.; SCHILLER, M.; et al.; Fluid Phase Equilib. 217 (2004) 1, 1-10; Colgate Palmolive, Piscataway, NJ, USA; Eng.) -Lindner 29-286