ARE PRODUCED BY REACTING METHYL NITRIETE AND PERFLUOROGLUTARIC ANHYDRIDE OR PERFLUOROSUCCINIC ANHYDRIDE AND THEN DECARBOXYLANTING THE RESULATNT PRODUCT. THE COMPOUNDS, WHICH CAN BE HYDROLYZED TO PRODUCE THE CORRESPONDING NITROSO-SUBSTITUTED FLUORCARBON ACIDS, ARE USED AS COMONOMERS IN NITRROSO RUBBERS.