Partition coefficients and fluorophilicities

In order to extract non-fluorous products from reactions involving fluorous solvents in a rational way, partition coefficients must be known. The design and optimization of fluorous catalysts and reagents require analogous data. In 1999, only a few partition coefficients involving fluorous and organic phases had been 

In rigorous work, partition coefficients are determined over a range of concentrations and extrapolated to infinite dilution. However, the concentrations used in Table 3.6 are close to those encountered in real-life fluorous/organic liquid/liquid biphasic separations, and the values for various classes of molecules are believed to have excellent cross-comparability. The measurement techniques have been critiqued elsewhere. It is preferable to express partition coefficients as ratios that have been normalized to 100, but some researchers express them as fractions or log quantities. 

Entries III-l and HI-2 show that the much more polar ketones cyclohexanone and 2-cyclohexen-1 -one also possess very high toluene phase affinities. The alcohol cyclohexanol (entry IV-1) exhibits a higher partition coefficient than cyclohexanone, and a phenyl-containing silyl ether derivative (entry XII-2) shows a value even 

Section IV of Table 3.6 lists several simple fluorous alcohols. The short-chain or Rf i/Rf2 alcohols in entries IV-2 and IV-3 show very poor fluorous phase affinities. As the perfluoroalkyl segment lengthens in the series Rf6(CH2)30H, Rfg(CH2)30H and Rfio(CH2)30H (entries IV-5, rV-7, IV-8), the fluorophilicities increase from 55.9 44.1 to 19.5 80.5. As expected, when a methylene group is removed from the first two compounds, the fluorophilicities also increase (47.4 52.6 and 26.5 73.5 entries IV-4, IV-6). Similar trends are found with all other functional groups in Table 3.6. 

Entry Substance Solvent system Partitioning % (organic fluorous) Ref. 

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