Predicting Physical Properties
Predicting Physical Properties
(OP)
At work I use the program DIPPR to precict physical properties. It is excellent, but is expensive. I have been looking on the internet for a free preferably downloadable program but have not found what I want - has anyone discovered something they would recommend?
The more you learn, the less you are certain of.





RE: Predicting Physical Properties
Good luck
RE: Predicting Physical Properties
density, specific heat, latent heat, MW, viscosity, heat of combustion, flammability limits, flash point, and surface tension. In english units preferably and with Antone constants and formula.
In other words as near to DIPPR as I can get without putting out $1000 for a single licence.
The more you learn, the less you are certain of.
RE: Predicting Physical Properties
DIPPR is very expensive, and just about anybody else that has something related is selling it at a high price.
The best thing I could find is the book
"The Properties of Gases and Liquids" Fifth Edition
by Poling, Prausnitz, and O'Connell. (About $80 from Amazon)
It has nearly all estimation methods laid out in very good detail with very handy tables.
RE: Predicting Physical Properties
For pure components, Properties of Gases and Liquids is excellent as already pointed out. I also have a book by Yaws called Physical Properties that is a great reference for some common compounds.
Regards,
Bob
RE: Predicting Physical Properties
The site is called xlfunctions.com as I recall. The price is fair. It costs $190 as I recall. I want it, but I wanted to hear from someone as to how easy it is to use and how good it is before I spend any money. Sounds like I am being cheap, but I have bought too many things that don't really work.
I work with gas compression, so I need the physical properties like specific heats and densities and compressibilities. Thanks, Lew9B
RE: Predicting Physical Properties
http://www.cheresources.com/physinternetzz.shtml
Amongst other links, the site contains a spreadsheet and an Excel Add-in that can be used to estimate the properties you're looking for. The database behind both the spreadsheet and add-in seems to be derived from the above mentioned book "Properties of Gases and liquids". It is only for pure components, though.
RE: Predicting Physical Properties
G&P Engineering produces PhysProps (about $50)
http://GPEngneeringSoftware.com
Cranium is an excellent package which allows one to draw the structure for estimating properties. There is a demonstration download which will do everything the purchased edition will except save compounds in the application. www.molknow.com
There is something to be said also for collecting a set of methods for properties which are the best available. The normal boiling point is a critical parameter for estimation of many other properties. Joback, Ambrose, and others give fair estimates of the boiling point. There is a newer, more accurate method from Morrero-Gani if anyone is interested.
A third package for estimating properties is "Predict" from Dragon Technology. It is an excellent tool.
Bill Choate
RE: Predicting Physical Properties
It works perfectly in earlier versions of excel, but Excel XP doesn't like it. You'll find that you'll be able to "install" it, but once you exit Excel and restart, the sheet is automatically hidden. I haven't found a way to work around this - I usually install the Add-In, use it for what I need, and then uninstall it before exiting Excel.
Hope this helps!
Jason
RE: Predicting Physical Properties
RE: Predicting Physical Properties
What are the macros for in the Physical Properties spreadsheet and do I need to use them in column's AI through AS?
This sheet is good, but does not have all of the properties I would like to have.
Thanks for the tip on this site for physical properties, it has been helpful.
The more you learn, the less you are certain of.
RE: Predicting Physical Properties
For example, to find the critical pressure, I used the following formula:
=IF(VLOOKUP($B$4,prop_table,6)=0,"Unknown",VLOOKUP($B$4,prop_table,6)*1.01325)
And to calculate the liquid viscosity, I entered the following formula:
=IF(VLOOKUP($B$4,prop_table,17)=0,"Unknown",10^(VLOOKUP($B$4,prop_table,17)*(1/(T+273.15)-1/VLOOKUP($B$4,prop_table,18))))
Note that the chemical name was entered in cell B4 (using a drop down list), and that the database was on the worksheet named prop_table. Hopefully this helps.
RE: Predicting Physical Properties
=VLOOKUP($B$4,prop_table,2)
The VLOOKUP function first looks into the first column of the table named "prop_table". When the component name entered in cell B4 (e.g. "WATER" or "1-BUTENE") is found in the table, the function returns the value in column 2 of that table. Column 2 contains the corresponding molecular weights.
Since column 3 contains the freeze points, following formula can be used to find this property:
=VLOOKUP($B$4,prop_table,3)
However, the function can be made more complicated, e.g. to convert the units from Kelvin to °C, or to return "Unknown" in case the database doesn't contain the specific property for the specified component. It would then look as follows:
=IF(VLOOKUP($B$4,prop_table,3)=0,"Unknown",VLOOKUP($B$4,prop_table,3)-273.15)
Good luck!
RE: Predicting Physical Properties
This often happens. The VLOOKUP can be set to be exact or approximate. Neither one will find, for example, "ethyl benzene" when searching for
"toluene".
RE: Predicting Physical Properties
By the way, toluene is methyl benzene, not ethyl benzene...
RE: Predicting Physical Properties
Keep in mind though that much of this data is generated by correlated / group contribution methods that may not be sufficiently accurate (depending on use).
One should also check out EPA's website, in particular WATER9, which has a list of 100,000 chemicals, their CAS # and chemical structures in SMILE form. With this info one could calculate (estimate is probably a better word) many chemical properties based on the book
referenced above.
Guido - Thanks. Toluene is methy benzene as you indicated.
RE: Predicting Physical Properties
These radicals may act as chemical
RE: Predicting Physical Properties