EXPERIMENTAL. PROCEDURES 63 sodium fluoride. After filtration, the product is distilled; yield, 300 parts of benzotrifluoride, b.p. 103°. The distillation tailings contain chloro-fluorides which can be reworked in a subsequent operation. 2,2-Difluoropropane (CH3CF2CH3). 19 In a reaction vessel equipped with an ice-cooled reflux condenser is placed 1.25 moles of antimony trifluoride containing 5% of bromine by weight. The vessel is cooled in ice, and 1.5 moles of 2,2-dichloropropane, cooled to 0°, is added. The reaction starts promptly and is regulated by means of an ice bath inter-mittently applied. At the end of the operation the vessel is heated to about 70°. The vapors passing through the condenser are caught in a water gasometer or in a receiver cooled with solid carbon dioxide. This operation, quickly performed, yields about 85% of 2,2-difluoropropane (b.p. -0.5°) and 10 to 15% of 2-fluoro-2-chloropropane (b.p. 35.2°). l,l,2,2,3,3-Hexachlor6-3-fluoropropane (CHCI2CCI2CCI2F).
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