JP5805812B2 - Integrated HFC Transformer-1234ZE Manufacturing Method - Google Patents

Description

Cross-reference of related applications

This application claims the benefit of US Provisional Patent Application No. 60 / 839,874, filed Aug. 24, 2006. This patent application is incorporated herein by reference.

The present invention relates to trans-1,3,3,3-tetrafluoropropene (HFO trans-1
234ze) for an integrated method. More particularly, the present invention is first described as 1,1.
, 1,3,3-pentafluoropropane is catalytically dehydrofluorinated, thus cis-1,3,3
, 3-tetrafluoropropene, trans-1,3,3,3-tetrafluoropropene and a method for the preparation of HFO trans-1234ze by preparing a mixture of hydrogen fluoride. Thereafter, optionally, hydrogen fluoride is recovered, cis-1234ze is catalytically isomerized to trans-1234ze, and trans-1,3,3,3-tetrafluoropropene is recovered. The integration of an isomerization reactor charged with a suitable isomerization catalyst helps to convert cis-1234ze to its trans isomer, which makes it possible to increase the single pass yield of trans-1234ze.

Chlorofluorocarbons (CFCs) such as trichlorofluoromethane and dichlorodifluoromethane have been used as refrigerants, blowing agents and diluents for gas sterilization. In recent years, there has been a widespread concern that certain chlorofluorocarbons can be harmful to the Earth's ozone layer. As a result, global efforts have been made to use halogenated carbons with fewer or no chlorine substituents. Therefore, the production of hydrofluorocarbons or compounds containing only carbon, hydrogen and fluorine can be accomplished with solvents, blowing agents, refrigerants, cleaning agents, aerosol propellants,
It continues to be an increasingly interesting subject to provide environmentally desirable products for use as heat transfer media, dielectrics, fire extinguishing compositions and power cycle working fluids. In this regard, trans-1,3,3,3-tetrafluoropropene (trans-1234ze) is a zero ozone depletion potential (ODP) and low global warming potential (GWP) refrigerant, blowing agent, aerosol propellant, solvent And compounds that have the potential to be used as fluorinated monomers.

It is known in the art to produce HFO-1234ze (ie, hydrofluoroolefin-1234ze). For example, (Patent Document 1) includes HCFC-12.
The fluorination of 1,1,1,3,3-pentachloropropane (HCC-240fa) is taught to form 33zd and small amounts of HFO-1234ze. (Patent Document 2)
Teaches fluorination of HCFC-1233zd to form HFC-1234ze. (Patent Document 3) also discloses HCFC- for forming HFO-1234ze.
1233zd fluorination is taught. (Patent Document 4) describes the formation of cis and trans isomers of HFO-1234ze by dehydrofluorination of HFC-245fa in the presence of an oxygen-containing gas using either a strong base or a chromium-based catalyst. Is taught. (
Patent Document 5) describes the formation of HFC-245fa via fluorination of HCC-240fa through an intermediate reaction product which is an azeotrope of HCFC-1233zd and HFO-1234ze.

It has been concluded that these known processes are not economical in terms of product yield. It has also been noted that large amounts of cis-1234ze are produced with their trans isomers in these known processes. Thus, trans-1234ze can be separated from the product mixture and cis-1234ze can be converted to HFC-2 via fluorination.
There is a need for means that can be recycled to 45fa or more preferably converted to trans-1234ze. Thus, the present invention provides highly pure trans-1234ze in higher yields than prior art processes, and trans-1234ze which can isomerize cis-1234ze to trans-1234ze as opposed to known processes. Provide an integrated method for manufacturing. In particular, 1,1,1,3,3-pentafluoropropane is dehydrofluorinated in the absence of an oxygen-containing gas to obtain cis-1,3,3,3-tetrafluoropropene and trans-1,3, It has now been found that trans-1234ze can be formed by preparing a mixture of 3,3-tetrafluoropropene and hydrogen fluoride. Thereafter, but preferably, hydrogen fluoride is recovered and cis-1234ze is catalytically isomerized to trans-1234ze, followed by recovery of trans-1,3,3,3-tetrafluoropropene. Thereafter, unconverted cis-1234ze and HFC
-245fa may be directly recirculated.

US Pat. No. 5,710,352 US Pat. No. 5,895,825 US Pat. No. 6,472,573 US Pat. No. 6,124,510 European Patent EP0939071

The present invention is a process for the production of trans-1,3,3,3-tetrafluoropropene comprising:
(A) dehydrofluorination of 1,1,1,3,3-pentafluoropropane, thus cis-1
, 3,3,3-tetrafluoropropene, trans-1,3,3,3-tetrafluoropropene and hydrogen fluoride, resulting in results;
(B) optionally recovering hydrogen fluoride from the result of step (a);
(C) at least part of cis-1,3,3,3-tetrafluoropropene is trans-1
Isomerizing to, 3,3,3-tetrafluoropropene;
(D) recovering trans-1,3,3,3-tetrafluoropropene;
A method comprising:

The present invention is a continuous integrated production process for the production of trans-1,3,3,3-tetrafluoropropene comprising:
(A) Dehydrofluorination of 1,1,1,3,3-pentafluoropropane carried out as a gas phase reaction, so that cis-1,3,3,3-tetrafluoropropene and trans-1,3 3
Producing a result comprising 1,3-tetrafluoropropene and hydrogen fluoride;
(B) recovering hydrogen fluoride from the result of step (a);
(C) at least part of cis-1,3,3,3-tetrafluoropropene is trans-1
Isomerizing to, 3,3,3-tetrafluoropropene;
(D) recovering trans-1,3,3,3-tetrafluoropropene;
A method is also provided.

The first step of the process is to dehydrofluorinate HFC-245fa, thus cis-1,3
, 3,3-tetrafluoropropene and trans-1,3,3,3-tetrafluoropropene and catalytic conversion of HFC-245fa by producing a result comprising a combination of hydrogen fluoride. Dehydrofluorination reactions are well known in the art. The dehydrofluorination of HFC-245fa is preferably carried out in a fixed bed reactor in the gas phase, more preferably in the gas phase.
The dehydrofluorination reaction may be carried out in any suitable reaction vessel or reactor, but is preferably lined with nickel and a nickel alloy or fluoropolymer such as Hastelloy, Inconel, Incoloy and Monel. It should be made of a material that can withstand the corrosive action of hydrogen fluoride, such as a container. These include fluorinated metal oxides that are in bulk form or supported, and metal halides that are in bulk form or supported and carbon-supported transition metals, metal oxides and metals. It may be a single tube or multiple tubes filled with a dehydrofluorination catalyst which may be one or more of the halides. Suitable catalysts include, but are not exclusively, fluorinated chromia (fluorinated Cr ₂ O ₃ ), fluorinated alumina (fluorinated Al ₂ O ₃ ), metal fluorides (eg, CrF ₃ , AlF ₃ ) and Fe / C. , Co / C, Ni / C, Pd / C and other carbon-supported transition metals (zero oxidation state). HFC-245fa is introduced into the reactor in pure form, in an impure state, or with any inert gas diluent such as nitrogen or argon. In a preferred embodiment of the invention, HFC-245fa is pre-evaporated or preheated before entering the reactor. Or HFC-245fa
Is evaporated inside the reactor. Useful reaction temperatures may range from about 100 ° C to about 600 ° C. A preferred temperature may be in the range of about 150 ° C to about 450 ° C, and a more preferred temperature may be in the range of about 200 ° C to about 350 ° C. The reaction may be carried out under atmospheric pressure, overpressure or vacuum. The vacuum pressure can be from about 5 Torr to about 760 Torr. HFC-24
The contact time of 5fa with the catalyst may range from about 0.5 seconds to about 120 seconds, but longer or shorter times can be used.

In a preferred embodiment, the process stream is downward or upward through the catalyst bed. It may be advantageous to periodically regenerate the catalyst after prolonged use while in place in the reactor. The regeneration of the catalyst is, for example, about 100 ° C. to about 400 ° C., preferably about 200 ° C.
May be carried out by any means known in the art by passing air or air diluted with nitrogen over the catalyst at a temperature of about 375 ° C for about 0.5 hours to about 3 days. . This includes about 25 ° C. to about 40 ° C. for fluorinated metal oxide and metal fluoride catalysts.
H ₂ at a temperature of about 100 ° C. to about 400 ° C., preferably about 200 ° C. to about 350 ° C. for HF treatment at a temperature of 0 ° C., preferably about 200 ° C. to about 350 ° C. or for a carbon-supported transition metal catalyst
Processing continues.

In an alternative embodiment of the invention, the dehydrofluorination of HFC-245fa is carried out at elevated temperatures with KOH.
Although not limited to NaOH, Ca (OH) ₂ and CaO, it is also possible to carry out by reacting a strong caustic solution containing them with HFC-245fa. In this case, the caustic concentration of the caustic solution is from about 2 wt% to about 100 wt%, more preferably from about 5 wt% to about 90 wt%, most preferably from about 10 wt% to about 80 wt%. is there. The reaction is about 20
° C to about 100 ° C, more preferably about 30 ° C to about 90 ° C, most preferably about 40 ° C to about 80 ° C.
It may be carried out at a temperature of ° C. As above, the reaction may be carried out under atmospheric pressure, overpressure or vacuum. The vacuum pressure can be from about 5 Torr to about 760 Torr. In addition, a solvent may optionally be used to help dissolve the organic compound in the caustic solution. Steps that may be employed in this case may be performed using solvents well known in the art for the purpose.

Optionally, but preferably, the hydrogen fluoride is then recovered from the results of the dehydrofluorination reaction. The recovery of hydrogen fluoride involves passing the composition resulting from the dehydrofluorination reaction through a sulfuric acid extractor to remove the hydrogen fluoride, then removing the extracted hydrogen fluoride from the sulfuric acid, and then removing the removed fluoride. This is done by distilling the hydrogen fluoride. Separation may be performed by adding sulfuric acid to the mixture while the mixture is in liquid or gaseous form. Usual weight ratios of sulfuric acid to hydrogen fluoride range from about 0.1: 1 to about 100: 1. Starting with a liquid mixture of fluorocarbon and hydrogen fluoride, sulfuric acid may then be added to the mixture.

The amount of sulfuric acid required for the separation depends on the amount of HF present in the system. From the solubility of HF in 100% sulfuric acid as a function of the temperature curve, it is possible to determine the practical minimum amount of sulfuric acid. For example, at 30 ° C., about 34 g of HF is dissolved in 100 g of 100% sulfuric acid. However, at 100 ° C., only about 10 g of HF dissolves in 100% sulfuric acid. Preferably, the sulfuric acid used in the present invention has a purity of about 50% to 100%.

In a preferred embodiment, the weight ratio of sulfuric acid to hydrogen fluoride ranges from about 0.1: 1 to about 1000:
1 range. More preferably, the weight ratio is in the range of about 1: 1 to about 100: 1, and most preferably in the range of about 2: 1 to about 50: 1. The reaction is preferably from about 0 ° C. to about 10
It is carried out at a temperature of 0 ° C, more preferably from about 0 ° C to about 40 ° C, most preferably from about 20 ° C to about 40 ° C. Extraction is usually performed at standard atmospheric pressure, although higher or lower pressure conditions may be used by those skilled in the art. When sulfuric acid is added to a mixture of fluorocarbon and HF, two phases are rapidly formed. An upper phase rich in fluorocarbons and a lower phase rich in HF / sulfuric acid are formed. The term “rich” means that the phase contains more than 50% of the indicated component in the phase, preferably more than 80% of the indicated component in the phase. The extraction efficiency of the fluorocarbon can range from about 90% to about 99%.

After separation of the phases, the upper phase rich in fluorocarbons is removed from the lower phase rich in hydrogen fluoride and sulfuric acid. This may be done by decanting, siphoning, distillation or other techniques well known in the art. Optionally, the fluorocarbon extraction may be repeated by adding more sulfuric acid to the removed lower phase. With a 2.25: 1 weight ratio of sulfuric acid to hydrogen fluoride, an extraction efficiency of about 92% can be obtained in one step. Preferably, the hydrogen fluoride and sulfuric acid are then separated. It is possible to utilize the low solubility of HF in sulfuric acid at high temperatures to recover HF from sulfuric acid. For example, at 140 ° C., only 4 g of HF dissolves in 100% sulfuric acid.
It is possible to recover the HF by heating the HF / sulfuric acid solution to 250 ° C. Thereafter, HF and sulfuric acid are recycled. That is, HF may be recycled to the reaction described above to produce HFC-245fa, or sulfuric acid may be recycled for use in further extraction steps.

In another embodiment of the present invention, the recovery of hydrogen fluoride from a mixture of fluorocarbon and hydrogen fluoride may be performed in the gas phase by a continuous process in which a stream of sulfuric acid is introduced into the stream of fluorocarbon and hydrogen fluoride. . This may be done in a standard scrubber column by flowing a stream of sulfuric acid counter-current through the stream of fluorocarbon and hydrogen fluoride. Sulfuric acid extraction is described, for example, in (US Pat. No. 5,895,639). This patent is hereby incorporated by reference.

Alternatively, HF can be recovered or removed by using a water scrubber or caustic scrubber, or by contacting with a metal salt. When using a water extractor, the technique is similar to that of sulfuric acid. When using caustic, HF is just removed from the system as a fluoride salt in aqueous solution. When using a metal salt (eg, potassium fluoride or sodium fluoride), the metal salt can be used in a stock solution or in combination with water. When using metal salts, it is possible to recover HF.

Thereafter, at least a portion of the cis-1,3,3,3-tetrafluoropropene is isomerized to trans-1,3,3,3-tetrafluoropropene. Cis-1,3,3,3-
Of tetrafluoropropene or a mixture of cis-1,3,3,3-tetrafluoropropene and trans-1,3,3,3-tetrafluoropropene and / or 1,1,1,3,3-pentafluoropropane The stream is fed to an isomerization reactor containing a suitable isomerization catalyst (eg, bulk or supported fluorinated metal oxide, bulk or supported metal fluoride, carbon-supported transition metal, etc.) to obtain cis-1234ze. Most of the transformer-1234
Convert to ze. The isomerization reaction may be carried out in any suitable reaction vessel or reactor, such as a vessel lined with nickel and a nickel alloy or fluoropolymer containing Hastelloy, Inconel, Incoloy and Monel, etc. Should preferably be composed of a material that resists corrosion. These may be single tubes or multiple tubes filled with an isomerization catalyst which may be a fluorinated metal oxide, a metal fluoride or a carbon-supported transition metal. Suitable catalysts include, but are not limited to, chromic fluoride, chromium fluoride, alumina fluoride, aluminum fluoride, and cobalt on carbon. Useful reaction temperatures range from about 25 ° C. to about 45
It may be in the range of 0 ° C. A preferred temperature may be in the range of about 50 ° C to about 350 ° C, and a more preferred temperature may be in the range of about 75 ° C to about 250 ° C. The reaction may be carried out under atmospheric pressure, overpressure or vacuum. The vacuum pressure can be from about 5 Torr to about 760 Torr. The contact time of the cis-1,3,3,3-tetrafluoropropene and the catalyst may range from about 0.5 seconds to about 120 seconds, but longer or shorter times may be used. Is possible.

Trans-1,3,3,3-tetrafluoropropene can be obtained by any means known in the art, such as by extraction and preferably by distillation,
It may be recovered from a by-product comprising 1,3,3,3-tetrafluoropropene and a reaction product mixture comprising any by-products and / or starting materials. Transformer-1,3,3
, 3-tetrafluoropropene, unconverted cis-1,3,3,3-tetrafluoropropene, unreacted HFC-245fa and any by-product mixture are passed through a distillation column. For example, the distillation may preferably be carried out in a standard distillation column at atmospheric pressure, overpressure or vacuum. The pressure is preferably less than about 300 psig, more preferably less than about 150 psig, most preferably 10
Less than 0 psig. The pressure in the distillation column essentially determines the distillation operating temperature. Trans-1
, 3,3,3-tetrafluoropropene has a boiling point of about -19 ° C. Cis-1,3,3
, 3-tetrafluoropropene has a boiling point of about 9 ° C. HFC-245fa is about 15 ° C
Has a boiling point of Trans-1,3,3,3-tetrafluoropropene may be recovered as a distillate by operating the distillation column at about -10 ° C to about 90 ° C, preferably about 0 ° C to about 80 ° C. A single distillation column or a multiple distillation column may be used. The distillate portion contains substantially all trans-1,3,3,3-tetrafluoropropene. The bottom stream of distillation is
Cis-1,3,3,3-tetrafluoropropene, HFC-245fa, small amount of unrecovered H
Contains F and any other impurities. In some cases, HF / H present in the bottom distillate
The residual amount of Cl is removed by passing through a water / caustic scrubber followed by a sulfuric acid drying tower. The bottom stream is then further distilled by using another distillation column. A mixture of cis-1234ze and HFC-245fa is recovered as distillate, which is then recycled back to the HFC-245fa dehydrofluorination reactor.

In the following alternative embodiments of the present invention, the HFC-245fa dehydrofluorination reactor and the cis-1234ze isomerization reactor can be combined or independent. The trans-1234ze separation can be after or before the cis-1234ze isomerization reaction.

Alternative 1
(1) HFC-245fa dehydrofluorination and cis-1234ze in one reaction vessel
Combination reaction of isomerization (2) HF recovery that may optionally be employed (3) Separation of trans-1234ze. Optionally, the remaining mixture is recycled back to step 1.

Alternative 2
(1) Catalytic dehydrofluorination of HFC-245fa to a composition containing trans / cis-1234ze (2) HF recovery that may optionally be employed (3) Separation of trans-1234ze. In this case, the outlet stream of (2) is fed to the distillation column. The product trans-1234ze is the rest of the mixture, ie cis-12
34ze, unreacted HFC-245fa and other minor side products as a distillate. The residual amount of HF / HCl present in the distillate is removed, followed by a drying step. (3)
The bottom stream from the distillation of is branched into two streams and fed to steps (4) and (1), respectively. Optionally, further distillation is performed by using another distillation column after step (3). In this distillation column, cis-1234ze and HF
The mixture with C-245fa is recovered as distillate, which is later fed to step (4). The bottom stream from this second distillation column is recycled and returned to step (1).
(4) The mixture of cis-1234ze / HFC-245fa from the catalytic isomerization step (3) of cis-1234ze is cis-1234
Feed most of the ze to an isomerization reactor containing a suitable isomerization catalyst to convert to trans-1234ze. The effluent from the catalytic reactor of step (4) is trans-1234z.
Feed to step (3) for separation of e.

Alternative 3
(1) catalytic dehydrofluorination of 245fa to trans / cis-1234ze (2) optional HF recovery (3) separation of trans-1234ze (4) catalytic isomerization of cis-1234ze. In this case, cis-1234z from step (3)
A mixture containing e and 245fa is fed to an isomerization reactor containing a suitable isomerization catalyst to convert most of the cis-1234ze to trans-1234ze.
(5) Separation of trans-1234ze. In this case, the effluent from step (4) is fed to a distillation column. The product trans-1234ze is the rest of the mixture, ie cis-123.
4ze, unreacted HFC-245fa and other minor by-products are separated as distillate. The bottom stream from the distillation of (5) is recycled back to step (1).

  The following non-limiting examples serve to illustrate the invention.

Example 1
Dehydrofluorination of HFC-245fa over selected catalysts Three different types of catalysts, namely fluorinated metal oxides, metal fluorides and supported metals, were dehydrofluorinated with 245fa in Example 1. Used for. In all cases, 20 cc of catalyst was used. 100% 245fa feed was flowed over the catalyst at a rate of 12 g / hr. Table 1
As shown in Table 1, all the catalysts listed in Table 1 are highly active during 245 dehydrofluorination (
245fa conversion> 80%) and selectivity to cis / trans-1234ze (90%
Exceeded).

Example 2
Isomerization of cis-1234ze over selected catalysts Three different types of catalysts were used for cis-1234ze isomerization in Example 2, namely fluorinated metal oxides, metal fluorides and supported metals. . In all cases, 20 cc of catalyst was used. 12 g of a mixture of 85.3% cis-1234ze / 14.7% 245fa
Over the catalyst at a rate of / hour. For the specified catalyst, a suitable reaction temperature was carefully selected so that almost no dehydrofluorination reaction occurred for HFC-245fa contained in the feed. As shown in Table 2, all catalysts except 0.5 wt% Co / AC listed in Table 2 have high activity (greater than 80% cis-1234ze conversion) and trans during cis-1234ze isomerization. It showed high selectivity for -1234ze (greater than 95%). 0.5
The weight% Co / AC catalyst showed moderate activity (cis-1234ze conversion 45%) and high selectivity for trans-1234ze (about 98%).

Example 3
In the isomerization this example cis -1234ze in the presence of HF over a fluorinated _Cr 2 _{O 3,} reactions 245fa de hydrofluorination reaction has been carried out on the fluorinated _Cr 2 _{O 3} catalyst at 350 ° C. Fluorinated Cr ₂ to perform the cis-1234ze isomerization reaction at 100 or 200 ° C. in the presence of HF (formed during 245fa dehydrofluorination in reactor 1) from the reactor 1 O ₃ catalyst was also introduced into the reactor 2 which was also charged. Table 3 shows the composition of the outlet gas of the two reactors. At 100 ° C., the mole% of trans-1234ze was slightly higher in the outlet gas of reactor 2 than the mole% of outlet gas of reactor 1, while cis-
The mole percent of 1234ze was slightly lower and the mole percent of 245fa was about the same. As a result, the mole% ratio of trans-1234ze to cis-1234ze increases slightly after the isomerization reaction (eg, 3.96 to 4.36 after passing through the stream for 1 hour), and cis throughout the isomerization of reactor 2. A small amount of -1234 was converted to trans-1234ze. At 200 ° C., the mole% of both trans-1234ze and cis-1234ze were slightly lower in the outlet gas of reactor 2 than the mole% of reactor 1 outlet gas, while the mole% of 245fa was slightly higher. It was. This indicates the occurrence of a hydrofluorination reaction between c / t-1234ze and HF. These results show that HF was mixed prior to feeding to the isomerization reactor to avoid trans / cis-1234ze hydrofluorination to 245fa and increased conversion of cis-1234ze to trans-1234ze. Suggest that it should preferably be removed from

Example 4
Combined HFC-245fa dehydrofluorination and cis-1234ze isomerization Two different types of catalysts were used for the combined reaction of Example 4, namely fluorinated metal oxides and metal fluorides. In either case, 20 cc of catalyst was used. Cis-123
A mixture of 4ze 8.2% / HFC-245fa 91.8% was flowed over the catalyst at a rate of 12 g / hr. For the specified catalyst, a suitable reaction temperature is carefully selected and HFC-245
Both fa dehydrofluorination and cis-1234ze isomerization were performed simultaneously. Assuming that cis-1234ze remains unchanged before and after the reaction, HF during the combined reaction
C-245fa conversion and trans-1234ze selectivity were calculated. As shown in Table 4, the nominal trans-1234ze selectivity was about 94%, which was much higher than the selectivity of the HFC-245fa dehydrofluorination reaction. This result shows that cis-1234z was used as a raw material.
FIG. 4 shows the occurrence of cis-1234ze isomerization to trans-1234ze during a combination reaction with an e / HFC-245fa mixture. This example shows that HFC-
It has been demonstrated that 245fa dehydrofluorination and cis-1234ze isomerization can be carried out simultaneously on the same catalyst in the same reactor.

These examples show that the selected catalyst is HFC-24 to cis / trans-1234ze.
It has been demonstrated to be extremely active for the dehydrofluorination of 5fa and the isomerization of cis-1234ze to trans-1234ze.

Although the invention has been particularly shown and described with reference to preferred embodiments, it will be readily appreciated by those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the invention. It is intended that the claims be interpreted to cover the disclosed embodiments, the alternatives described above and all equivalents thereto.
The present invention includes the following aspects.
[1]
A process for the production of trans-1,3,3,3-tetrafluoropropene, comprising:
(A) Dehydrofluorination of 1,1,1,3,3-pentafluoropropane, thus cis-1,3,3,3-tetrafluoropropene and trans-1,3,3,3-tetrafluoro Producing a result comprising propene and hydrogen fluoride;
(B) optionally recovering hydrogen fluoride from the result of step (a);
(C) isomerizing at least a portion of cis-1,3,3,3-tetrafluoropropene to trans-1,3,3,3-tetrafluoropropene;
(D) recovering trans-1,3,3,3-tetrafluoropropene;
Including methods.
[2]
After step (d), cis-1,3,3,3-tetrafluoropropene or a mixture of cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropane is added. The subsequent step to be recovered and a mixture of cis-1,3,3,3-tetrafluoropropene or cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropane. The method of [1], further comprising a subsequent step that is recycled back to step (a) or steps (a) and (c).
[3]
The method according to [1], wherein step (b) is performed.
[4]
The method according to [1], wherein the steps (a) and (c) are performed independently.
[5]
The method according to [1], wherein the steps (a) and (c) are combined and performed as a single process step.
[6]
The method according to [1], wherein the step (d) is performed after the step (c).
[7]
The method according to [1], wherein the step (d) is performed after the step (a) but before the step (c).
[8]
The method according to [1], wherein the step (d) is performed after the step (a) but before the step (c), and then the step (d) is repeated after the step (c).
[9]
The method according to [1], wherein trans-1,3,3,3-tetrafluoropropene is recovered by distillation.
[10]
The result of step (c) is distilled and trans-1,3,3,3-tetrafluoropropene is converted to hydrogen fluoride and cis-1,3,3,3-tetrafluoropropene and 1,1,1,3, The method according to [1], wherein the step (d) is performed by recovering as a distillate containing one or more kinds of 3-pentafluoropropane and a residue.
[11]
The method of [10], further comprising a subsequent step of removing hydrogen fluoride from the residue.
[12]
[10] The method according to [10], further comprising a subsequent step of removing hydrogen fluoride from the residue by passing the residue through a scrubber containing water and caustic, and a subsequent drying step.
[13]
A subsequent step of recovering at least one of cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropane from the residue, the recovered cis-1, The method according to [10], further comprising a subsequent step of recycling at least one of 3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropane back to step (a). the method of.
[14]
The method according to [1], wherein the dehydrofluorination is performed as a gas phase reaction.
[15]
The method according to [1], wherein the dehydrofluorination is performed as a gas phase reaction.
[16]
The dehydrofluorination is performed according to [1], wherein the dehydrofluorination is performed with a catalyst containing one or more of a fluorinated metal oxide, a metal fluoride, and a carbon-supported transition metal, which are in a bulk form or are supported. the method of.
[17]
In order to remove hydrogen fluoride, the hydrogen fluoride is recovered by passing the composition through a sulfuric acid extractor, and then the extracted hydrogen fluoride is removed from the sulfuric acid, and then the removed hydrogen fluoride is removed. The method according to [1], wherein distillation is performed.
[18]
The method according to [1], wherein the isomerization is performed in an isomerization reactor in the presence of an isomerization catalyst.
[19]
Said isomerization in an isomerization reactor in the presence of an isomerization catalyst comprising one or more of a fluorinated metal oxide and a metal fluoride and a carbon-supported transition metal in bulk form or supported The method according to [1].
[20]
A continuous integrated production process for the production of trans-1,3,3,3-tetrafluoropropene,
(A) Dehydrofluorination of 1,1,1,3,3-pentafluoropropane carried out as a gas phase reaction, so that cis-1,3,3,3-tetrafluoropropene and trans-1,3 Producing a result comprising 3,3-tetrafluoropropene and hydrogen fluoride;
(B) recovering hydrogen fluoride from the result of step (a);
(C) isomerizing at least a portion of cis-1,3,3,3-tetrafluoropropene to trans-1,3,3,3-tetrafluoropropene;
(D) recovering trans-1,3,3,3-tetrafluoropropene;
Including methods.
[21]
The method according to [20], wherein the steps (a) and (c) are performed independently.
[22]
The method according to [20], wherein the steps (a) and (c) are combined and performed as a single process step before the step (b).
[23]
The method according to [20], wherein step (d) is performed after step (c).
[24]
The method according to [20], wherein the step (d) is performed after the step (a) but before the step (c).
[25]
The method according to [20], wherein the step (d) is performed after the step (a) but before the step (c), and then the step (d) is repeated after the step (c).

Claims (4)

A process for the production of trans-1,3,3,3-tetrafluoropropene, comprising:
(A) 1,1,1,3,3-pentafluoropropane is dehydrofluorinated in the presence of a fluorinated chromia catalyst in the form of a lump , and thus cis-1,3,3,3-tetrafluoro Producing a result comprising propene, trans-1,3,3,3-tetrafluoropropene and hydrogen fluoride;
(B) optionally recovering hydrogen fluoride from the result of step (a);
(C) isomerizing at least a portion of cis-1,3,3,3-tetrafluoropropene to trans-1,3,3,3-tetrafluoropropene;
(D) recovering trans-1,3,3,3-tetrafluoropropene;
Including methods.   Cis-1,3,3,3-tetrafluoropropene or a mixture of cis-1,3,3,3-tetrafluoropropene and 1,1,1,3,3-pentafluoropropane in step (a) or step The method of claim 1, further comprising the step of recycling back to (a) and (c). The method according to claim 1 or 2, wherein steps (a) and (c) are combined and performed as a single process step. 4. The method of claim 3, wherein the single process step is performed in one reaction vessel.