Method for purifying 1,2-difluoroethylene (HFO-1132)
AssigneeDaikin Industries, Ltd.
InventorsTakashi Usui, Kazuhiro Takahashi, Tomoyuki Iwamoto
Life of this patent
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Abstract
The present disclosure provides a method for purifying HFO-1132 to a high purity while suppressing the isomerization and loss of HFO-1132. Specifically, the present disclosure provides a method for purifying 1,2-difluoroethylene, which is HFO-1132, the method comprising, in this order, step 1 of bringing a composition comprising trans-1,2-difluoroethylene, which is HFO-1132(E), and water into contact with a zeolite having an average pore size of 2 to 4 Å to reduce the water content from the composition; and step 2 of recovering a purified product containing HFO-1132(E) and a reduced content of water, and containing less than 0.1% by volume of HFO-1132(Z).
Claims5
A method for purifying 1,2-difluoroethylene, which is HFO-1132, the method comprising:
- step 1 of producing a composition comprising trans-1,2-difluoroethylene, which is HFO-1132(E), cis-1,2-difluoroethylene, which is HFO-1132(Z), and water during a dehydrofluorination reaction of 1,1,2-trifluoroethane or an isomerization reaction of HFO-1132(E) and/or HFO-1132(Z) in the presence of a metal catalyst, and then,
- step 2 of allowing the composition to pass through a column filled with a zeolite having an average pore size of 2 to 4 Å to reduce the water content from the composition,
- wherein an isomerization percentage of the HFO-1132(E) and HFO-1132(Z) in passing through the column follows the following formulas:
- (1132(E)(inlet %)/(1132(E,Z)(inlet %))−(1132(E)(outlet %)/(1132(E,Z)(outlet %))<|0.01|, and
- (1132(Z)(inlet %)/(1132(E,Z)(inlet %))−(1132(Z)(outlet %)/(1132(E,Z)(outlet %))<|0.01|, and
- wherein step 2 is performed at a temperature of 0 to 100° C.
Dependencies are inferred from the claim text.