Sciencemadness Discussion Board

Partition Coefficients

jimmyboy - 11-3-2012 at 02:00

Does anyone know of a good database for solvent-solvent partition coefficients? I am interested in using some old (frugal) chromatography techniques and this information would be useful ..
Most of the info I see is spread throughout different journals with little organization

unionised - 11-3-2012 at 11:31

lots of pharmaceuticals are characterised by (among other things) their octanol: water partition coefficient.
Often called Pow (with the O and w subscripted)
http://en.wikipedia.org/wiki/Partition_coefficient#Some_Octa...

Nicodem - 11-3-2012 at 12:53

Beilstein is probably the only chemical reference database that thoroughly abstracts also the published partition coefficient (logP) data. It is still the best place to look for any kind of properties of compounds. (Keep in mind that Beilstein was recently renamed to Reaxys.)

The calculated n-octanol/water logP is often quite unusually reliable (relatively so, for a calculated value). So, unless you need an exact value (which is rarely the case in practice), you can just use the calculated value. Several chemistry software packages have this option (ChemDraw, commercial ChemSketch) or you can use one of the on-line tools. Unfortunately, this is only for the n-octanol/water combination, but it can give you some idea of how other solvent combinations might behave on some specific compound.