METHOD FOR REDUCING 1,1,1,2,2-PENTAFLUOROPROPANE (HFC-245CB) IN A PROCESS FOR PRODUCING TRANS-1,3,3,3-TETRAFLUOROPROPENE (HFO-1234ZE(E))
A method for reducing 1,1,1,2,2-pentafluoropropane (HFC-245cb) in a trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) manufacturing process including catalyst conditioning, temperature reduction, and contact time reduction. The method includes dehydrofluorinating 1,1,1,3,3-pentafluoropropane (HFC-245fa) with a catalyst mixture to produce a product mixture with HFO-1234ze(E) and HFC-245cb, and either incorporating a conditioned catalyst, using a lower temperature for the dehydrofluorination, or reducing the contact time for the dehydrofluorination to reduce the formation of HFC-245cb.
1 . A method for reducing 1,1,1,2,2-pentafluoropropane (HFC-245cb) in a trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) manufacturing process comprising:
dehydrofluorinating 1,1,1,3,3-pentafluoropropane (HFC-245fa) with a catalyst mixture to produce a product mixture comprising trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)), 1,1,1,2,2-pentafluoropropane (HFC-245cb), and hydrogen fluoride (HF),
wherein the catalyst mixture comprises from 10 wt. % to 90 wt. % of a conditioned catalyst having a runtime of from 20 to 500 days in the HFO-1234ze(E) manufacturing process, based on the total weight of the catalyst mixture.
2 . The method of claim 1 , wherein the catalyst mixture comprises 10 wt. % to 90 wt. % of a conditioned catalyst having a runtime of from 50 to 500 days in the HFO-1234ze(E) manufacturing process, based on the total weight of the catalyst mixture.
3 . The method of claim 1 , wherein the catalyst mixture comprises 50 wt. % of a conditioned catalyst with a runtime from 300 to 500 days in the HFO-1234ze(E) manufacturing process.
4 . The method of claim 1 , wherein the catalyst mixture comprise a dehydrofluorination catalyst selected from the group consisting of fluorinated metal oxides, metal halides, and carbon supported transition metals.
5 . The method of claim 1 , further comprising recovering trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) from the product mixture by distillation.
6 . The method of claim 1 , wherein the amount of 1,1,1,2,2-pentafluoropropane (HFC-245cb) in the product mixture is from 0.1 ppm to 100 ppm.
7 . A method for reducing of 1,1,1,2,2-pentafluoropropane (HFC-245cb) in a trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) manufacturing process comprising:
dehydrofluorinating 1,1,1,3,3-pentafluoropropane (HFC-245fa) with a catalyst mixture to produce a product mixture comprising trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)), 1,1,1,2,2-pentafluoropropane (HFC-245cb), and hydrogen fluoride (HF),
wherein the dehydrofluorination step is conducted at a temperature of from 10° C. to 310° C.
8 . The method of claim 7 , wherein the dehydrofluorination step is conducted at a temperature of from 288° C. to 310° C.
9 . The method of claim 7 , wherein the temperature of the dehydrofluorination step is maintained with an electric heating element, a hot oil, or a molten salt.
10 . The method of claim 7 , further comprising feeding a reactant mixture comprising 1,1,1,3,3-pentafluoropropane (HFC-245fa) into the dehydrofluorination reaction, wherein the reactant mixture is at a temperature of from 288° C. to 310° C.
11 . The method of claim 10 , wherein the temperature of the reactant mixture is maintained with an electric heating element, a hot oil, or a molten salt.
12 . The method of claim 7 , further comprising recovering trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) from the product mixture by distillation.
13 . The method of claim 7 , wherein the amount of 1,1,1,2,2-pentafluoropropane (HFC-245cb) in the product mixture is from 0.1 ppm to 100 ppm.
14 . A method for reducing 1,1,1,2,2-pentafluoropropane (HFC-245cb) in a trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) manufacturing process comprising:
dehydrofluorinating 1,1,1,3,3-pentafluoropropane (HFC-245fa) with a catalyst mixture to produce a product mixture comprising trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)), cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z)), 1,1,1,2,2-pentafluoropropane (HFC-245cb), and hydrogen fluoride (HF),
wherein the contact time in the dehydrofluorination step is from 1 second to 40 seconds.
15 . The method of claim 14 , wherein the contact time is from 1 second to 20 seconds.
16 . The method of claim 14 , wherein the dehydrofluorination step is conducted at a temperature of from 288° C. to 310° C.
17 . The method of claim 14 , wherein the amount of 1,1,1,2,2-pentafluoropropane (HFC-245cb) in the product mixture is from 0.1 ppm to 100 ppm.
18 . A composition comprising trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)) as produced by the process according to claim 1 .
19 . The composition of claim 18 , wherein the amount of 1,1,1,2,2-pentafluoropropane (HFC-245cb) in the composition is from 0.1 ppm to 100 ppm.
20 . A composition comprising:
trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E));
cis-1,3,3,3-tetrafluoropropene (HFO-1234ze(Z));
0.1 ppm to 100 ppm of 1,1,1,2,2-pentafluoropropane (HFC-245cb); and
and hydrogen fluoride (HF).