Michael D. Frenkel

Thermodynamic and thermophysical properties of the reference ionic liquid: 1-Hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide (including mixtures). Part 2. Critical evaluation and recommended property values (IUPAC Technical Report)

This article is a product of IUPAC Project 2002-005-1-100 (Thermodynamics of ionic liquids, ionic liquid mixtures, and the development of standardized systems). Experimental results of thermodynamic, transport, and phase equilibrium studies made on a reference sample of the ionic liquid 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide are summarized, compared, and critically evaluated to provide recommended values with uncertainties for the properties measured. Properties measured included thermal properties (triple-point temperature, glass-transition temperature, enthalpy of fusion, heat capacities of condensed states), volumetric properties, speeds of sound, viscosities, electrolytic conductivities, relative permittivities, as well as properties for mixtures, such as gas solubilities (solubility pressures), solute activity coefficients at infinite dilution, and liquid-liquid equilibrium temperatures. Recommended values with uncertainties are provided for the properties studied experimentally. The effect of the presence of water on the property values is discussed.

Thermodynamic and thermophysical properties of the reference ionic liquid: 1-Hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide (including mixtures). Part 1. Experimental methods and results (IUPAC Technical Report)

This article summarizes the results of IUPAC Project 2002-005-1-100 (Thermodynamics of ionic liquids, ionic liquid mixtures, and the development of standardized systems). The methods used by the various contributors to measure the thermophysical and phase equilibrium properties of the reference sample of the ionic liquid 1-hexyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]amide and its mixtures are summarized along with the uncertainties estimated by the contributors. Some results not previously published are presented. Properties of the pure ionic liquid included thermal properties (triple-point temperature, glass-transition temperature, enthalpy of fusion, heat capacities of condensed states), volumetric properties, speeds of sound, viscosities, electrolytic conductivities, and relative permittivities. Properties for mixtures included gas solubilities, solute activity coefficients at infinite dilution, liquid-liquid equilibrium temperatures, and excess volumes. The companion article (Part 2) provides a critical evaluation of the data and recommended values with estimated combined expanded uncertainties.

TRC SOURCE Database: A Unique Tool for Automatic Production of Data Compilations

Thermochemical and thermophysical properties of chemicals are the basis of most simulations of commercial processes. The TRC SOURCE database is an extensive archive of numerical experimental values of thermophysical properties extracted from the worlds scientific literature. A suite of input/output routines that utilize current database technology has been developed. The database in combination with suitable software enables the automatic retrieval, interpretation, selection, and formatting of a wide range of thermophysical properties. Their output supports the automatic production of user specified compilations and the direct interaction with user-written application programs.

ThermoData Engine (TDE): software implementation of the dynamic data evaluation concept. 3. Binary mixtures.

ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported in this journal. The present paper describes the first application of this concept to the evaluation of thermophysical properties for ternary chemical systems. The method involves construction of Redlich-Kister type equations for individual properties (excess volume, thermal conductivity, viscosity, surface tension, and excess enthalpy) and activity coefficient models for phase equilibrium properties (vapor-liquid and liquid-liquid equilibrium). Constructed ternary models are based on those for the three pure component and three binary subsystems evaluated on demand through the TDE software algorithms. All models are described in detail, and extensions to the class structure of the program are provided. Reliable evaluation of properties for the binary subsystems is essential for successful property evaluations for ternary systems, and algorithms are described to aid appropriate parameter selection and fitting for the implemented activity coefficient models (NRTL, Wilson, Van Laar, Redlich-Kister, and UNIQUAC). Two activity coefficient models based on group contributions (original UNIFAC and NIST-KT-UNIFAC) are also implemented. Novel features of the user interface are shown, and directions for future enhancements are outlined.

ThermoData Engine (TDE): Software Implementation of the Dynamic Data Evaluation Concept. 4. Chemical Reactions

ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported recently in this journal. This paper describes the first application of this concept to the evaluation of thermodynamic properties for chemical reactions. Reaction properties evaluated are the enthalpies, entropies, Gibbs energies, and thermodynamic equilibrium constants. Details of key considerations in the critical evaluation of enthalpies of formation and of standard entropies for organic compounds are discussed in relation to their application in the calculation of reaction properties. Extensions to the class structure of the program are described that allow close linkage between the derived reaction properties and the underlying pure-component properties. Derivation of pure-component enthalpies of formation and of standard entropies through the use of directly measured reaction properties (enthalpies of reaction and equilibrium constants) is described. Directions for future enhancements are outlined.

XML-based IUPAC standard for experimental, predicted, and critically evaluated thermodynamic property data storage and capture (ThermoML) (IUPAC Recommendations 2006)

ThermoML is an Extensible Markup Language (XML)-based new IUPAC standard for storage and exchange of experimental, predicted, and critically evaluated thermophysical and thermochemical property data. The basic principles, scope, and description of all structural elements of ThermoML are discussed. ThermoML covers essentially all thermodynamic and transport property data (more than 120 properties) for pure compounds, multicomponent mixtures, and chemical reactions (including change-of-state and equilibrium reactions). Representations of all quantities related to the expression of uncertainty in ThermoML conform to the Guide to the Expression of Uncertainty in Measurement (GUM). The ThermoMLEquation schema for representation of fitted equations with ThermoML is also described and provided as supporting information together with specific formulations for several equations commonly used in the representation of thermodynamic and thermophysical properties. The role of ThermoML in global data communication processes is discussed. The text of a variety of data files (use cases) illustrating the ThermoML format for pure compounds, mixtures, and chemical reactions, as well as the complete ThermoML schema text, are provided as supporting information.

Global communications and expert systems in thermodynamics: Connecting property measurement and chemical process design

Unprecedented growth in the number of custom-designed software tools for engineering applications has created an interoperability problem between the formats and structures of thermodynamic data files and required input/output structures designed for application software products. Various approaches for standardization of thermophysical and thermochemical property data storage and exchange are analyzed in this paper. Emphasis is made on the development of the XML-based IUPAC standard for thermodynamic data communications: ThermoML. A new process for global data submission and dissemination in the field of thermodynamics based on ThermoML and Guided Data Capture software is described. Establishment of the global submission and dissemination process for thermodynamic data lays the foundation for implementation of the new concept of dynamic data evaluation formulated at NIST/TRC, which requires the development of large electronic databases capable of storing essentially all “raw” experimental data known to date with detailed descriptions of relevant metadata and uncertainties. The combination of these databases with expert software designed primarily to generate recommended data based on available “raw” experimental data and their uncertainties leads to the possibility of producing data compilations automatically “to order”, forming a dynamic data infrastructure. Implementation of the dynamic data evaluation concept for pure compounds in the new NIST/TRC ThermoData Engine software is discussed.

Windows-Based Guided Data Capture Software for Mass-Scale Thermophysical and Thermochemical Property Data Collection

Guided data capture software (GDC) is described for mass-scale abstraction from the literature of experimental thermophysical and thermochemical property data for organic chemical systems involving one, two, and three components, chemical reactions, and chemical equilibria. Property values are captured with a strictly hierarchical system based upon rigorous application of the thermodynamic constraints of the Gibbs phase rule with full traceability to source documents. Key features of the program and its adherence to scientific principles are described with particular emphasis on data-quality issues, both in terms of data accuracy and database integrity.

ThermoData Engine (TDE): Software Implementation of the Dynamic Data Evaluation Concept. 5. Experiment Planning and Product Design§

ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported recently in this journal. In the present paper, we describe development of an algorithmic approach to assist experiment planning through assessment of the existing body of knowledge, including availability of experimental thermophysical property data, variable ranges studied, associated uncertainties, state of prediction methods, and parameters for deployment of prediction methods and how these parameters can be obtained using targeted measurements, etc., and, indeed, how the intended measurement may address the underlying scientific or engineering problem under consideration. A second new feature described here is the application of the software capabilities for aid in the design of chemical products through identification of chemical systems possessing desired values of thermophysical properties within defined ranges of tolerance. The algorithms and their software implementation to achieve this are described. Finally, implementation of a new data validation and weighting system is described for vapor-liquid equilibrium (VLE) data, and directions for future enhancements are outlined.

ThermoData Engine (TDE): Software Implementation of the Dynamic Data Evaluation Concept. 9. Extensible Thermodynamic Constraints for Pure Compounds and New Model Developments

ThermoData Engine (TDE) is the first full-scale software implementation of the dynamic data evaluation concept, as reported in this journal. The present article describes the background and implementation for new additions in latest release of TDE. Advances are in the areas of program architecture and quality improvement for automatic property evaluations, particularly for pure compounds. It is shown that selection of appropriate program architecture supports improvement of the quality of the on-demand property evaluations through application of a readily extensible collection of constraints. The basis and implementation for other enhancements to TDE are described briefly. Other enhancements include the following: (1) implementation of model-validity enforcement for specific equations that can provide unphysical results if unconstrained, (2) newly refined group-contribution parameters for estimation of enthalpies of formation for pure compounds containing carbon, hydrogen, and oxygen, (3) implementation of an enhanced group-contribution method (NIST-Modified UNIFAC) in TDE for improved estimation of phase-equilibrium properties for binary mixtures, (4) tools for mutual validation of ideal-gas properties derived through statistical calculations and those derived independently through combination of experimental thermodynamic results, (5) improvements in program reliability and function that stem directly from the recent redesign of the TRC-SOURCE Data Archival System for experimental property values, and (6) implementation of the Peng-Robinson equation of state for binary mixtures, which allows for critical evaluation of mixtures involving supercritical components. Planned future developments are summarized.