Perfluorinated oxygen- and sulfur-containing compounds as extractants for gold(III)

A series of highly fluorinated compounds of the type {CF3(CF2)5CH2CH2}3P=O, [{CF3(CF2)5CH2CH2}2P(E)CH2CH2P(E){CH2CH2(CF2)5CF3}] and {CF3(CF2)5CH2CH2}2C=E (E = O or S) have been examined for their ability to extract gold(III) from aqueous solutions. The phosphine oxides have been studied under liquid–liquid extraction conditions from water into perfluorohexane and found to give poor distribution ratios. The bidentate phosphine oxide, ketone and thioketone were studied under solid–liquid extraction conditions and were substantially better with extraction of up to 80% of Au(III). In addition, the crystal structure of {CF3(CF2)5CH2CH2}3P=O has been determined.