Manufacturing method of 1,2-dichlorohexafluorocyclopentene

A method for preparing 1,2 dichlorohexafluorocyclopentene, comprising:

• in step one:
• pyrolysing dicyclopentadiene, as raw material, to obtain cyclopentadiene, with nitrogen or other inert gas as a diluent in a molar ratio of the diluent to dicyclopentadiene of 1:0.5 to 3, wherein the pyrolysing is at a reaction pressure of 0.1 MPa to 1.5 MPa, a reaction temperature of 300° C. to 450° C. and a contact time of 5 s to 30 s;
• in step two:
• subjecting cyclopentadiene, as raw material, to a chlorination reaction in a liquid phase with chlorine to obtain 1,2,3,4-tetrachlorocyclopentane, in a molar ratio of chlorine to cyclopentadiene of 1 to 3:1, wherein the chlorination reaction is at a reaction temperature of 0° C. to 40° C., and a reaction time of 1 h to 10 h;
• in step three:
• subjecting 1,2,3,4-tetrachlorocyclopentane, as raw material, to a chlorofluorination reaction with hydrogen fluoride and chlorine in a gas phase in the presence of a chromium-based catalyst to obtain 1,2-dichlorohexafluorocyclopentene, in a molar ratio of 1,2,3,4-tetrachlorocyclopentane, hydrogen fluoride and chlorine of 1:5 to 20:5, wherein the chlorofluorination reaction is at a reaction pressure of 0.1 MPa to 1.5 MPa, a reaction temperature of 370° C. to 450° C. and a contact time of 2 s to 30 s.