66 ALIPHATIC FLUORINE COMPOUNDScompletely and facilitates filtration. The aqueous layer is separated ascompletely as practicable, and the remainder is filtered with suction andair-dried on the filter. The filtrate separates into a layer of acetylenetetrabromide and a layer of water. The solid material is removed fromthe filter, placed in a bottle, covered with chloroform, vigorously shakenfor twenty minutes, and then filtered by suction. Pure mercuric bromideis left on the filter. The filtrate is a chloroform solution containing from75 to 100 cc. of acetylene tetrabromide. By distillation of the chloro-form it is possible to recover the acetylene tetrabromide.1,2-Dibromofiuoroethane and l-Bromo-2,2-difluoroethane.By aprocedure analogous to that just described, 1,2,2-tribromoethane wasconverted to the mono- and di-fluoro derivatives. The reaction temper-ature had to be lower for good results. At 0°, the yield of mixed productswas 50%; at—20°,60-65%. At higher temperatures the yield was only30%.The boiling points are 121° and 57°, respectively.
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