Production method for hexafluoro-1,3-butadiene

A method for producing hexafluoro-1,3-butadiene, the method comprising:

• a reaction step of reacting a halogenated butane represented by chemical formula, CF2X1-CFX2-CFX3-CF2X4 (X1, X2, X3, and X4 are each independently a halogen atom other than a fluorine atom) in an organic solvent in the presence of zinc to eliminate the halogen atoms, X1, X2, X3, and X4, other than the fluorine atoms to generate hexafluoro-1,3-butadiene, giving a reaction product containing the hexafluoro-1,3-butadiene;
• and
• an aftertreatment step of separating the hexafluoro-1,3-butadiene from the reaction product produced in the reaction step, then adding water to a reaction product residue after the separating, wherein a mass ratio of the reaction product residue to the water ([amount of reaction product residue]/[amount of water]) is 0.5 or more and 2.0 or less, performing solid-liquid separation when a solution obtained by addition of water to the reaction product residue contains solid substances, and removing the organic solvent, giving an aqueous solution of zinc halide.