Physical Chemistry Division (I)

Commission on Thermodynamics (I.2)

SUBCOMMITTE ON THERMODYNAMIC DATA

Project 121/18/98 - Thermochemical, thermodynamic and transport properties of halogenated organic compounds and mixtures

---

INTERNATIONAL CERTIFICATE OF RESEARCH NEEDS

As part of the IUPAC Project 121/18/98 to improve knowledge and understanding of the thermodynamic and transport properties of halogenated alkanes, especially fluorinated alkanes, and their mixtures with alkanes and with other halogenated alkanes, the following list of research needs has been identified following the round-table discussions at the Workshop held in Pisa, Italy, December 15-18, 1999 and in subsequent communications between participants:

MEASUREMENTS

1. Propane/butane + refrigerant
2. Binary and/or ternary HFCs
3. Higher alkane + fluoroalkane mixtures
4. Application of HFC's in medical areas
5. Systems of lubricant oils and refrigerants

CALCULATIONS

1. Molecular Orbital Calculations
2. Molecular Simulations
3. Correlations

COMMUNICATIONS/DATABASE

---

MEASUREMENTS

1. Propane/butane + refrigerant

• Thermodynamic properties and, with lower priority, transport properties (including diffusion) of mixtures of propane + ethane-derived HFCs, n-butane + ethane-derived HFCs and n-pentane + R245ca (for example).
  Measurements on the mixtures with butane are particularly encouraged.
• A systematic investigation of the variation in property values for propane + propane based HFCs to provide important information of the effect of replacement of H by F.

2. Binary and/or ternary HFCs (R-32, R-134a, R-125, R-143a)

• Thermodynamic properties and, with lower priority, transport properties (including diffusion) for binary mixtures of HFCs with large size differences, such as R23 +R143a, R32 + R152a and R32 + fluorinated propanes.
• The ternary system R32+R125+ R123. Measurements will provide an extended test of methods for mixture property prediction.

3. Higher alkane + fluoroalkane mixtures

• Thermodynamic properties and, with lower priority, transport properties (including diffusion) of the mixture C6H14 + C6F14. Such studies are of interest for those working in fluorous biphasic catalysis. Also, the study of mixtures of partially fluorinated alkanes with alkanes, with perfluoroalkanes, and with oxygenated alkanes (ethers and polyethers), and of fluorinated oxygenated alkanes with alkanes, and with perfluoroalkanes.

4. Application of HFC's in medical areas

• Diffusion coefficients and solubilities of O2, N2, CO2, and NO in perfluorooctyl-bromide, and viscosity measurements of this and other related compounds as basic research for studies in liquid ventilation and/or artificial blood substitutes.

5. Systems of lubricant oils and refrigerants

• Transport properties and phase equilibria measurements are required for lubricants which are considered for use with HFCs. A systematic study could begin with precursors of these lubricants (which are ester derivatives of pentaerythritol) such as 3,3-diethyl-pentane, then progress to their hydroxy and ester derivatives.

CALCULATIONS

1. Molecular Orbital Calculations

• Intermolecular potential calculations using ab initio methods (GAUSSIAN 98) should be made for HFC's with two carbon atoms (recommended key systems: HCF2CF3 and CHF2CHF2). The goal should be to characterize all possible methane-, ethane-, and propane-derived hydrofluorochlorocarbons by computing their molecular structure.
• The relative merits of the SPARTAN software, GAUSSIAN 98, other commercial products and the public domain software GAMESS must be assesed.

The information gained from these studies will be of great value in developing models based on the molecular architecture and charge distribution for theory-based calculation of macroscopic properties.

2. Molecular Simulations

• These provide insight into the molecular interactions, for example, in providing evidence for associations in R32 via H-F bonds. Simulators should focus on the methane-derivatives. Studies on systems of dipolar hard spheres and molecules interacting with the Stockmayer potential are particularly encouraged, as these polar model fluids are more relevant for halocarbons than non-polar model fluids.
• Properties of metastable (superheated) liquids should be investigated by simulation studies. These are of fundamental interest and of practical importance to design heat exchangers, but are difficult to measure.

3. Correlations

• Improved correlation methods are required for data representation, particularly over extended ranges of pressure as well as temperature, based on a molecular model. There is also a need for better prediction methods, especially for properties of multicomponent mixtures from binary data.

COMMUNICATIONS/DATABASE

• Investigation of the use of "SELF" (Standard Electronic File") formats for the exchange and storage of data.
• Collection of data and results on an FTP-server to intensify the collaboration among participants and make the project more efficient.
• A webpage of the IUPAC Project.

> Back to Project Description