300 ml of acetonitrile, 33.9 g (0.3 mol) of vinylbenzylamine (synthesized by the method described in "Kobunshi Gakkai Yokoshu", vol. 26, page 834 (G3 C-07) (1977) from chloromethylstyrene (meta:para=about 6:4); p.b.: 82° C./1.5 mm Hg), 30.3 g (0.3 mol) of triethylamine, and 0.5 g of 2,6-di-t-butylphenol were charged into a 500-ml three-necked flask equipped with a stirrer, and a calcium chloride tube, and the mixture was then cooled with ice water. 109.5 g (0.3 mol) of the 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-n-heptanoic acid chloride synthesized in Synthesis Example 1 was added dropwise, with stirring and ice-cooling. Next, the mixture was stirred for 1 hour at room temperature, and the deposited triethylamine hydrochloride was filtered off. The filtrate was distilled under reduced pressure to remove the acetonitrile, 200 ml of ethyl acetate was added to the remainder to be dissolved, and white insolubles were filtered off. The filtrate was distilled under reduced pressure to be condensed, and 300 ml of n-hexane was added to the remainder, followed by cooling. The deposited white crystals were filtered and dried in vacuo at room temperature, thus producing 90.1 g (yield: 65.2%; m.p.: 53° to 57° C.) of 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-n-heptanoic acid vinylbenzylamide.
