Synthesis of technically useful perfluorocarboxylic acids

The influence of technological parameters on the dehydroiodination of perfluoroalkylethene iodides (CF3)2CF(CF2CF2)nCH2CH2I, where n = 1, 2, 3 and 4, has been investigated. The most advantageous conditions for the two-stage oxidation of (CF3)2CF(CF2CF2)nCHCH2, with ozone in the first stage, followed by the oxidation with hydrogen peroxide to the perfluorocarboxylic acids, were determined. The effects of temperature and time on the conversion of perfluoroalkylethenes during the oxidation with ozone were studied. In the second stage, the selectivity of transformation (of each homologue) to the perfluorocarboxylic acid in relation to the theoretical amount resulting from a quantity of perfluoroalkylethene used and the conversion of perfluoroalkylethene in the temperature range of 10–80 °C has been determined.