Patent ID: 9346724
Filing Date: 2016-05-24
CPC Classification: C07C

Claim Text:
1. A method for preparing 2,3,3,3-tetrafluoropropene, comprising: a) heating and vaporizing hydrogen fluoride and 1,1,2,3-tetrachloropropene, and introducing hydrogen fluoride and TCP to a first reactor for reaction in the presence of an A-type catalyst, whereby yielding a first product mixture comprising 2,3-dichloro-3,3-difluoropropene, wherein a mole ratio between hydrogen fluoride and 1,1,2,3-tetrachloropropene is between 5:1 and 60:1, a reaction temperature is between 200 and 500° C., and a space velocity is between 200 and 2000 h b) preheating the first product mixture comprising 2,3-dichloro-3,3-difluoropropene, introducing the first product mixture comprising 2,3-dichloro-3,3-difluoropropene to a second reactor for reaction in the presence of a B-type catalyst, whereby yielding a second product mixture comprising 2,3,3,3-tetrafluoropropene, wherein the reaction temperature of the second reactor is higher than the reaction temperature of the first reactor by between 30 and 180° C., and the temperature of the preheated first product mixture comprising 2,3-dichloro-3,3-difluoropropene is higher than the reaction temperature of the first reactor and lower than the reaction temperature of the second reactor; c) introducing the second product mixture comprising 2,3,3,3-tetrafluoropropene to a first distillation column for a first distillation to separate a first distillate from first bottom components, and refining the first distillate to obtain hydrochloric acid; d) introducing the first bottom components to a second distillation column for a second distillation to separate a second distillate from second bottom components, and circulating the second distillate to the first reactor, in which the second distillate is HF; and e) introducing the second bottom components to a third distillation column for a third distillation to separate a third distillate from third bottom components, collecting the third distillate to obtain 2,3,3,3-tetrafluoropropene, and circulating the third bottom components to the first reactor.