Antimony trifluorodichloride

Preparation of Antimony Trifluorodichloride (SbF3Cl2). This is made in the steel reaction vessel, described on p. 59. A known quantity of antimony fluoride is placed in the vessel the vessel is evacuated, the needle valve is closed, and the whole is weighed. Connection is established to a chlorine cylinder, and the needle valve is opened to permit qhlorine to fill the vessel. Part of it is absorbed rapidly by the salt, with evolution of heat. Soon the reaction slows down as indicated by the rate of pressure fall when the needle valve is dosed. Weighing indicates the amount of chlorine present in the vessel. When the absorption practically ceases, the valve is closed, and the connection with the chlorine tank is removed. The reaction vessel is alternately heated gently, then allowed to cool in order to permit SbFsCl2, which is a viscous liquid, to flow and expose fresh surfaces of crystalline antimony trifluoride. The operation is ended after the absorption of the desired quantity of chlorine. 

Hexachlor6-3-fluoropropane (CHCI2CCI2CCI2F).30 In a 1-1. flask, a mixture of 1160 g. of 1,1,2,2,3,3,3-heptachloropropane and 740 g. of antimony trifluorodichloride is vigorously stirred so that the temperar ture does not exceed 50°. After the mixture has cooled to 30°, it is slowly heated to 130-140° and maintained at this temperature for five hours. It is then cooled, poured into water, washed with hydrochloric acid—to remove antimony salts—then with water, anchdried. The yield is 907 g. of reaction product containing approximately 60 g. of 1,1,2,2-tetrachloro-3,3,3-trifluoropropane (b.p. 130°), 315 g. of 1,1,2,2,3-penta-chloro-3,3-difluoropropane (b.p. 168°), and 435 g. of 1,1,2,2,3,3-hexa-chloro-3-fluoropropane (b.p. 210°). 

The behavior of a number of chlorine derivatives of methane, ethane, and propane toward antimony trifluoride activated by the trifluorodichloride is shown in Table I. The yield given for each product is the maximum obtained when the reaction was adjusted for the preparation... 

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