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- 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.
- 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.
- 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.
Page last modified 5 April 2000.
Copyright ©2000 International Union of Pure and Applied Chemistry.
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