(747h) Universal Graph Structures for Property Estimation

Over the past century, physical-chemical properties have become an increasingly important element of industrial and engineering chemistry (O'Connell et al. 2009). In particular, the uses of physical-chemical properties have become more sophisticated as new chemical products with precise molecular structures have entered the marketplace. The multitude of competing chemical mechanisms that control these properties has required chemical product designers to become more creative and, as a result, the number of property models available to today’s chemical engineer can be overwhelming.

This paper highlights a technique to consolidate molecular structure-based property methods into a single, common underlying structure domain from which all available structure-based physical property models can be utilized. Each user-defined physical property model is mapped to the universal graph structure and stored in a pre-configured molecular library database. Once mapped, no changes to the underlying code are necessary to identify new structure configurations introduced by the user-defined property model. Furthermore, only minimal changes are required to the property estimation tool to fully implement the model. The method makes extensive use of the IUPAC International Chemical Identifier (InChI) to map chemical species into molecular graphs and back again.

A case study on species important to the natural gas industry will be utilized to illustrate the molecular library databases use with physical property models.

O'Connell, J. P., R. Gani, P. M. Mathias, G. Maurer, J. D. Olson and P. A. Crafts (2009). "Thermodynamic Property Modeling for Chemical Process and Product Engineering: Some Perspectives." Industrial & Engineering Chemistry Research 48(10): 4619.