thermophysical property data, estimation methods and laboratory measurementNormal boiling point · Vapor pressure · Liquid viscosity · Thermal conductivity · Surface tension · Critical properties — by group contribution from molecular structure
Every number on this site is an estimate produced by a correlation, not a measurement and not a certified value. Please read this before relying on one.
The service is provided free of charge and "as is". Rareytec Co., Ltd. makes no warranty, express or implied, as to the accuracy, completeness or fitness for any particular purpose of the values it returns, and accepts no liability for any loss or damage arising from their use. You use the results at your own risk and remain responsible for verifying them.
The values are group-contribution estimates calculated from molecular structure alone. No experimental data for your compound is consulted. Typical deviations from experiment are a few percent for well-behaved molecules inside the stated ranges, but individual compounds can deviate substantially — particularly small molecules, strongly associating compounds, and structures unlike those the methods were fitted to.
These estimates must not be used, without independent verification against experimental data, as the basis for anything where an error could cause harm — among others the design or rating of pressure equipment and relief systems, fire, flammability or explosion assessment, toxicological or exposure evaluation, transport classification, or any regulatory submission.
Where a method is outside the range in which it was shown to work, the site withholds the value or flags it. Those limits are aids, not guarantees: they are evaluated using an estimated critical temperature, so a compound can sit on the wrong side of a limit without the site knowing. A value that carries no warning has not thereby been certified.
Nothing you enter is stored. The site keeps no database of queries, sets no cookies, and uses no analytics or tracking of any kind. Results are computed on request and discarded.
One thing does leave the server. When you enter a compound name, it is sent to the public PubChem service (US National Institutes of Health) to look up the corresponding structure; when you enter a structure, it is likewise sent to PubChem to look up a name for display. If your structure is confidential, be aware that this lookup happens — and note that the estimation itself does not need it: the calculation runs entirely locally on the structure you supply.
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The estimation methods are the published work of J. Rarey, Y. Nannoolal and co-workers, with the thermal conductivity method by O. Govender and co-workers and the surface tension method based on unpublished work by E. Olivier; the primary references are listed at the foot of the calculator. The implementation is an independent one by Rareytec Co., Ltd.. If you use results from this site in published work, please cite the original method papers, and state that the values are estimates.
Questions, corrections and reports of a suspicious number are welcome — https://www.rareytec.com.