45 research outputs found

    Thermodynamic Properties of N-Methyl-Substituted Ethane-1,2-diamines: Experimental and Computational Study

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    © 2016 American Chemical Society.Vapor pressures for four N-methyl-substituted ethane-1,2-diamines were measured using the transpiration method. Enthalpies of vaporization were derived from the temperature dependence of the vapor pressures. Consistency of the experimental data was assessed and confirmed with group-additivity (GA) and quantum-chemical (QC) methods. Further confirmation of the results is provided through combined assessment with properties reported in the literature for the parent compound ethane-1,2-diamine and a group of alkyl-substituted alkane-1,2-diamines. The effective application of modern QC methods in critical evaluation of enthalpies of vaporization and enthalpies of formation is demonstrated

    Gas Hydrate Research Database and Web Dissemination Channel

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    To facilitate advances in application of technologies pertaining to gas hydrates, a United States database containing experimentally-derived information about those materials was developed. The Clathrate Hydrate Physical Property Database (NIST Standard Reference Database {number_sign} 156) was developed by the TRC Group at NIST in Boulder, Colorado paralleling a highly-successful database of thermodynamic properties of molecular pure compounds and their mixtures and in association with an international effort on the part of CODATA to aid in international data sharing. Development and population of this database relied on the development of three components of information-processing infrastructure: (1) guided data capture (GDC) software designed to convert data and metadata into a well-organized, electronic format, (2) a relational data storage facility to accommodate all types of numerical and metadata within the scope of the project, and (3) a gas hydrate markup language (GHML) developed to standardize data communications between 'data producers' and 'data users'. Having developed the appropriate data storage and communication technologies, a web-based interface for both the new Clathrate Hydrate Physical Property Database, as well as Scientific Results from the Mallik 2002 Gas Hydrate Production Research Well Program was developed and deployed at http://gashydrates.nist.gov

    Reference materials for phase equilibrium studies. 1. Liquid–liquid equilibria (IUPAC Technical Report)

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    This article is the first of three projected IUPAC Technical Reports resulting from IUPAC Project 2011-037-2-100 (Reference Materials for Phase Equilibrium Studies). The goal of this project is to select reference systems with critically evaluated property values for the validation of instruments and techniques used in phase equilibrium studies of mixtures. This report proposes seven systems for liquid–liquid equilibrium studies, covering the four most common categories of binary mixtures: aqueous systems of moderate solubility, non-aqueous systems, systems with low solubility, and systems with ionic liquids. For each system, the available literature sources, accepted data, smoothing equations, and estimated uncertainties are given

    Reference materials for phase equilibrium studies. 2. Solid-liquid equilibria (IUPAC Technical Report)

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    This article is the second of three projected IUPAC Technical Reports on reference materials for phase equilibrium studies. The goal of this project was to select reference systems with critically evaluated property values for the verification of instruments and techniques used in phase equilibrium studies of mixtures. This report proposes seven systems for solid–liquid equilibrium studies, covering the four most common categories of binary mixtures: aqueous systems with organic solutes, aqueous systems with inorganic solutes, non-aqueous systems, and systems with low solubility. For each system, the available literature sources, accepted data, smoothing equations, and estimated uncertainties are given

    Extension of ThermoML: The IUPAC standard for thermodynamic data communications (IUPAC Recommendations 2011)

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    ThermoML is an XML-based approach for storage and exchange of experimental, predicted, and critically evaluated thermophysical and thermochemical property data. Extensions to the ThermoML schema for the representation of speciation, complex equilibria, and properties of biomaterials are described. The texts of 14 data files illustrating the new extensions are provided as Supplementary Information together with the complete text of the updated ThermoML schema

    Thermodynamic Properties of N-Methyl-Substituted Ethane-1,2-diamines: Experimental and Computational Study

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    © 2016 American Chemical Society.Vapor pressures for four N-methyl-substituted ethane-1,2-diamines were measured using the transpiration method. Enthalpies of vaporization were derived from the temperature dependence of the vapor pressures. Consistency of the experimental data was assessed and confirmed with group-additivity (GA) and quantum-chemical (QC) methods. Further confirmation of the results is provided through combined assessment with properties reported in the literature for the parent compound ethane-1,2-diamine and a group of alkyl-substituted alkane-1,2-diamines. The effective application of modern QC methods in critical evaluation of enthalpies of vaporization and enthalpies of formation is demonstrated
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