Organic fluorides. X. The formation of fluoro‐oils and resins by the polymerization of hydrofluorocarbons with fluorine

Abstract

Fluorine diluted with nitrogen reacted with hydrofluorocarbons such as benzotrifluoride, in solution in fluorocarbons or in pentachloroethane, to give high-boiling products, presumably from condensation reactions proceeding simultaneously with fluorination. Treatment of these products in the liquid phase first with fluorin-under more drastic conditions, and then with silver difluoride, gave a series of perfluoro-lubricants and resins.Highly fluorinated lubricants and resins are of particular value where non-inflammability and resistance to chemical attack are required, and various methods for the production of such materials have been reported. The two main processes developed for the preparation of pure short-chain fluorocarbons have been utilized also for the production of fluorinated lubricants ; thus Cady, Grosse, Barber, Burger & Sheldon ( At the beginning of the preeent work attempts were made to fluorinate aliphatic and aromatic hydrocarbons in the liquid phase. Large volumes of nitrogen were employed to dilute the fluorine gas, the reaction vessels were cooled to -70" in some cases, and the liquids were stirred at high speeds. Little or no success attended the experiments ; highly coloured unstable tars were the main fluorine-containing products obtained. It was next shown that fluorocarbons such as perfluoromethylcyclohexane and perfluoroheptane were relatively inert to fluorine. Attempts to fluorinate suspensions of hydrocarbons in fluorocarbons were not successful, since condensation occurred, and the hydrocarbon was quickly deposited on the walls of the reaction vessel as a tar, thus arresting further fluorination. Aliphatic hydrocarbons treated in this way usually yielded tars containing 25 o/b-309:, fluorine.