The invention belongs to the technical field of
fluoride preparation, and particularly relates to a method for preparing
hexafluoroethane at low temperature. The method comprises the following steps: S1, liquefying
tetrafluoroethylene: vacuumizing a reaction kettle, introducing
tetrafluoroethylene, and cooling the reaction kettle with
liquid nitrogen until
tetrafluoroethylene is completely liquefied; s2, preparing
hexafluoroethane through reaction of
fluorine-
nitrogen mixed gas and tetrafluoroethylene: introducing the
fluorine-
nitrogen mixed gas into the tetrafluoroethylene liquefied in the step S1 in a bubbling manner, stirring and reacting, and continuously stirring and reacting after the introduction of the
fluorine-
nitrogen mixed gas is finished, so as to obtain the
hexafluoroethane; and S3, gas purification: after the reaction is finished, purging the
gas phase space of the reaction kettle with nitrogen to remove residual gas in the reaction kettle, then heating the reaction kettle until the hexafluoroethane is gasified, and carrying out alkali washing,
drying and rectification to obtain the high-purity hexafluoroethane. In the preparation method disclosed by the invention, the reaction is
safer and easier to control under a low-temperature condition, and the preparation method disclosed by the invention is simple in process, high in
reaction speed, high in yield, few in product
impurity, easy to purify and suitable for industrial production.