Oligomers of tetrafluoroethylene (C2F4)n where n is 4 to 6 react at 25*-100*C with aqueous solutions of sodium or potassium hydroxides to give novel oxygen-containing derivatives in which the oxygen is located in hydroxyl, carbonyl or carboxyl groups. With 5-15% by weight solutions of the hydroxides the tetramer yields a tertiary alcohol; the pentamer yields the ketone (C2F5)2(CF3)C.CH2COCF3, and hexamer yields a mixture of the ketone (C4F9)(C2F5)(CF3)C.CH2COCF3 and the ketene (C2F5)2(CF3)C.C(CO).CF(CF3)(C2F5). With 30-60% solutions the pentamer yields the acid (C2F5)2(CF3)C.CH2COOH. These oligomer derivatives are intermediates for making surfactants and oleophobic compounds for application to textiles and leather.