Method for preparing 2,3,3,3-tetrafluoropropene

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−1;
• 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 180oC, 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.