Thermomorphic metal scavengers: A synthetic and multinuclear NMR study of highly fluorinated ketones and their application in heavy metal removal

The preparation of a ketone with two long chain perfluoroalkyl groups is reported via the coupling reaction of a perfluorinated alkylzinc reagent and a perfluoro-acid chloride. This ketone has been investigated in the heterogeneous removal of heavy metals M2+ (M = Sn, Cd, Pb, Hg) and As5+ from aqueous solutions and removal of these metals from organic solvents using the unique thermomorphic properties of the fluorous ketone. In addition, a comprehensive 13C NMR study of one of the intermediates in the synthesis, 2H,2H,3H,3H-perfluoronanoic acid, has allowed the determination of all 1JC–F and 2JC–F coupling constants. Also reported is the crystal structure of the acid CF3(CF2)5CH2CH2CO2H.

Graphical abstractA ketone with perfluoroalkyl chains has been developed for the extraction of M(II) (M = Sn, Cd, Hg, Pb) and As(V) from aqueous and organic solvents under heterogeneous and homogeneous conditions using the unique thermomorphic properties of these ligands.Figure optionsDownload full-size imageDownload as PowerPoint slide