Patent ID: 8415516

Claim:
A process for producing 1,2,3,4-tetrachlorohexafluorobutane, comprising feeding fluorine gas to 1,2,3,4-tetrachlorobutane using plural reactors in the presence of a solvent containing hydrogen fluoride and in the absence of a catalyst to allow the 1,2,3,4-tetrachlorobutane and the fluorine gas to react with each other, wherein the plural reactors are comprised of a first reactor on an upstream side and a second reactor on a downstream side and are arranged in series, and a part or all of unreacted fluorine discharged from the first reactor is introduced into the second reactor, the concentration of fluorine gas in a dilute mixed gas introduced into the first reactor is not less than 30% by volume, and the concentration of fluorine gas contained in discharged gas from the second reactor is not more than 10% by volume.