Utilizing poly(hexafluoropropylene oxide) ligands in fluorous biphase catalysis (FBC)

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Many industrial processes employ homogeneous catalysts, catalysts that are in the same phase as the reactants and products.  However, a difficulty with homogeneous catalysis involves the separation of the products from the catalyst so that the catalyst can then be reused.  This difficulty in separation results in high costs, both environmental as well as financial. A potential solution to this problem involves fluorous biphase catalysis (FBC).  Such catalytic processes require two phases that do not blend at room temperature but combine at higher temperatures; an organic phase contains the reactant species, while a fluorous phase contains the catalyst.  Heating allows the two phases to blend and the reaction takes place catalytically in this single phase.  On cooling the two phases separate out again, with one containing the catalyst that can then be reused and the other phase containing the reaction products. The success of this process is therefore dependent upon the preferential solubility of the catalyst.  Since triaryl phosphine ligands have proved to be useful in so many catalytic processes, efforts to design such catalysts have thus far employed these ligands with a perfluoroalkyl "ponytail" attached. However, to this point the desired solubility properties have not yet been attained using such ligands.  A further problem with employing perfluoroalkyl ponytails is that they introduce environmental challenges; as these compounds degrade they become bio-accumulative and persistent.  This may be solved using fluorinated polyethers which do not possess the same environmental concerns, and will also have solubility properties more suited to FBC. The primary objectives of this research program are two-fold.  1) to develop new triarylphosphine ligands containing fluorinated polyethers, -CF2CF(CF3)[OCF2CF(CF3)]nF; 2) to synthesize Rh(I) complexes of these ligands and test their catalytic ability in hydroformylation, hydrogenation, Heck reactions, and polymerizations.