Process for reducing chlorofluorocarbon impurities in manufacture of trans-1, 3, 3, 3-tetrafluoropropene (HFO-1234ze (E))

Abstract

Two methods of reducing CFC impurities, and in particular CFC-114, in the process of producing HFO-1234ze (E) from the reaction of CFC-113 with HF. A first process involves separating and distilling an intermediate stream or a recycle stream to purge CFC-113 from the process. The second process involves operating the separation at a higher pressure, avoiding the formation of an azeotrope between CFC-113 and HFC-245fa. In some embodiments, a CFC-113 / HFC-245fa azeotrope is discussed, along with other optional processes for removing or mitigating CFC-113, including a further separation of removing CFC-114 from the HFO-1234ze (E) product and / or removing CFC-113 from the HFC-245fa feed, to produce a HFO-1234ze (E) product that is substantially free of CFC-114 and other CFC impurities.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is an international application of U.S. patent application No. 18 / 218,691 filed on July 6, 2023, and claims priority to U.S. Provisional Application No. 63 / 389,174 filed on July 14, 2022 and U.S. Provisional Application No. 63 / 415,457 filed on October 12, 2022, all of which are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to a method of reducing the amount of chlorofluorocarbon impurities in a process for producing trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E)). Background Art

[0004] Chlorofluorocarbons (CFCs) have been found to be widely used in many applications, including as refrigerants, aerosol propellants, blowing agents, heat transfer media, gaseous dielectrics and fire extinguishing. In recent years, people have paid extensive attention to the fact that some chlorofluorocarbons may be harmful to the ozone layer of the earth. Therefore, the whole world is making efforts to use halogenated hydrocarbons containing less chlorine substituents or no chlorine substituents. Therefore, producing hydrofluorocarbons or compounds that only contain carbon, hydrogen and fluorine has always been a subject of concern, to provide environmentally desirable products used as solvents, blowing agents, refrigerants, cleaning agents, aerosol propellants, heat transfer media, dielectrics, fire extinguishing compositions, power cycle working fluids, and for the production of hydrofluoroolefins (HFOs) that do not damage the ozone layer and also have low global warming potential values. Summary of the invention

[0005] The present disclosure is based on the following discovery: in the process of producing HFO-1234ze (E) by reacting CFC-113 with HF, CFC impurities are formed, and in particular CFC-114. It has been found that the amount of such CFC impurities can be reduced by separating and distilling the intermediate stream or the recycle stream to remove CFC-113 from the process. It has also been found that the amount of CFC impurities can be reduced by operating the separation at a higher pressure to avoid forming an azeotrope between CFC-113 and HFC-245fa. Other optional processes for removing or mitigating CFC-113 include further separations of removing CFC-114 from the HFO-1234ze (E) product and / or removing CFC-113 from the HFC-245fa feed to produce a HFO-1234ze (E) product substantially free of CFC-114 and other CFC impurities.

[0006] In one form thereof, the present disclosure provides a process for producing HFO-1234ze(E), the process comprising: reacting a feed stream comprising HFC-245fa and CFC-113 in a reactor in the presence of a catalyst to form a first product stream comprising HFO-1234ze(E), unreacted HFC-245fa, and CFC-113; separating the first product stream into a second product stream comprising HFO-1234ze(E) and a third product stream comprising unreacted HFC-245fa and CFC-113; distilling the third product stream to produce an overhead recycle stream and a bottoms stream, the recycle stream comprising unreacted HFC-245fa and a first amount of CFC-113, and the bottoms stream comprising a second amount of CFC-113 greater than the first amount; and conveying the recycle stream back to the feed stream.

[0007] In another form thereof, the present disclosure provides a method for removing CFC-113 from an HFC-245fa feed stream in the production of HFO-1234ze(E), the method comprising: feeding HFC-245fa to a separation device, the HFC-245fa also comprising a first amount of CFC-113; recovering a purified HFC-245fa stream from the separation device, the purified HFC-245fa stream having a second amount of CFC-113 less than the first amount.

[0008] In another form thereof, the present disclosure provides a method for removing CFC-114 from an HFO-1234ze(E) product stream in an HFO-1234ze(E) process, the method comprising feeding HFO-1234ze(E) to a separation unit, the HFO-1234ze(E) further comprising a first amount of CFC-114; recovering a purified HFO-1234ze(E) stream from the separation unit, the purified HFO-1234ze(E) stream having a second amount of CFC-114 less than the first amount.

[0009] In another form thereof, the present disclosure provides an azeotrope or azeotrope-like composition consisting of CFC-113 and HFC-245fa. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other features of the present disclosure and the manner of achieving them will become more apparent and the present disclosure itself will be better understood by referring to the following description of the embodiments of the present disclosure in conjunction with the accompanying drawings.

[0011] Figure 1 A flow chart of a process for removing CFC-113 and CFC-114 in a HFO-1234ze(E) process is provided.

[0012] Figure 2 is a graph of temperature versus weight percent HFC-245fa as measured in an ebulliometer study of HFC-245fa and CFC-113 according to Example 1.

[0013] Figure 3 is a graph of temperature versus HFC-245fa composition (mass % relative to CFC-113) at a pressure of 5 psia.

[0014] Figure 4 is a graph of temperature versus HFC-245fa composition (mass % relative to CFC-113) at a pressure of 10 psia.

[0015] Figure 5 is a graph of temperature versus HFC-245fa composition (mass % relative to CFC-113) at a pressure of 14.7 psia.

[0016] Figure 6 It is a graph of pressure versus azeotropic composition (mass %) of HFC-245fa and CFC-113.

[0017] The exemplifications set forth herein illustrate embodiments of the present disclosure, and such exemplifications should not be construed as limiting the scope of the present disclosure in any way. DETAILED DESCRIPTION

[0018] I. Definitions

[0019] Table 1

[0020] Compound names and corresponding IUPAC names as used herein

[0021] name IUPAC name CFC-113 1,1,2-Trichloro-1,2,2-trifluoroethane CFC-113a 1,1,1-Trichloro-2,2,2-trifluoroethane CFC-114 1,2-Dichloro-1,1,2,2-tetrafluoroethane CFC-114a 1,1-Dichloro-1,2,2,2-tetrafluoroethane HFC-245fa 1,1,1,3,3-Pentafluoropropane HFO-1234ze(E) trans-1,3,3,3-tetrafluoropropene HFO-1234ze(Z) cis-1,3,3,3-tetrafluoropropene

[0022] As used herein, the terms "CFC-113" and "CFC-114" refer to both CFC-113 and CFC-113a and CFC-114 and CFC-114a, respectively.

[0023] Unless otherwise indicated, the term "HFO-1234ze" refers to both HFO-1234ze(E) and HFO-1234ze(Z) together.

[0024] II. Method for Reducing CFC-114 in HFO-1234ze(E)

[0025] The present disclosure is based on the discovery that during the HFO-1234ze(E) production process, CFC-113 and CFC-113a present in the HFC-245fa feed react with HF produced by the dehydrofluorination reaction of HFC-245fa to form CFC-114 and CFC-114a. These CFCs are impurities and are ozone depleting substances, and it is therefore desirable to control the content of CFCs in the HFO-1234ze(E) product. In some jurisdictions, regulations limit the content of these impurities in certain emission uses.

[0026] Therefore, there is a need for methods to remove CFC-113 from HFC-245fa feed and CFC-114 from HFO-1234ze(E) final product. The present disclosure is directed to solving the problem of removing CFC-113 and CFC-114 at several locations or unit operations during the HFO-1234ze(E) manufacturing process.

[0027] HFO1234ze(E) can be industrially produced by a dehydrofluorination reaction as shown in the following equation 1.

[0028] Equation 1

[0029]

[0030] The production of HFO-1234ze(E) involves the catalytic conversion of HFC-245fa, producing a mixture by dehydrofluorination of HFC-245fa, the mixture comprising a combination of cis and trans isomers of HFO-1234ze and hydrogen fluoride. Preferably, the dehydrofluorination of HFC-245fa can be carried out in the gas phase, such as in a fixed bed reactor. The dehydrofluorination reaction can be carried out in any suitable reaction vessel or reactor, but it should preferably be composed of a material (such as nickel and its alloys, including Hastelloy, Inconel, Incoloy and Monel) or a container lined with a fluoropolymer that is resistant to the corrosive effects of hydrogen fluoride.

[0031] The conversion of HFC-245fa to HFO-1234ze(E) and HFO-1234ze(Z) is limited by equilibrium. Therefore, the reactor product stream is usually subjected to several separation steps to recover HFO-1234ze(E) as a product and to recycle unconverted HFC-245fa to the reactor.

[0032] If the feed HFC-245fa stream contains impurities, such as CFC-113, the impurities will accumulate in the recycle stream, which can hinder the conversion rate and yield of the dehydrofluorination reaction. For example, if the recycle stream contains CFC-113, a portion of the CFC-113 entering the reactor can react with HF produced by the HFC-245fa dehydrofluorination reaction to convert CFC-113 to CFC-114 by the reaction shown in Equation 2 below.

[0033] Equation 2

[0034]

[0035] The formation of CFC-114 in the reactor is a significant disadvantage since it is an undesirable impurity and difficult to separate from HFO-1234ze(E), especially at low CFC-114 concentrations.

[0036] Another alternative for reducing the accumulation of CFC-113 and CFC-114 would involve distilling the HFC-245fa feed stream to remove CFC- 113. However, it has been found that separation of CFC-113 from HFC-245fa is difficult, particularly at low concentrations of CFC-113, as discussed below, where CFC-113 / HFO-245fa azeotropes may exist, and as also discussed further below, such azeotropes are prevalent, particularly at low pressures.

[0037] III. Process for producing HFO-1234ze(E)

[0038] A general process for producing HFO-1234ze(E) is described below. The present disclosure encompasses two methods that can be incorporated into the HFO-1234ze(E) process to reduce the level of CFC impurities in the HFO-1234ze(E) product.

[0039] In the first method, CFC-113 can be purged from an intermediate stream of the process where separation is easier, thus allowing the use of smaller, less expensive equipment with lower energy consumption and lower yield losses, as discussed in more detail in Section IV. This intermediate stream is separated and distilled to provide a recycle stream comprising unconverted HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), and reduced amounts of CFC-113, and a waste stream comprising impurities that can be removed from the system, which recycle stream can be fed back to the reactor.

[0040] In the second method, the reaction mixture is exposed to increased pressure during the separation stage, which avoids the formation of a uniform minimum boiling azeotrope at about 3.5 weight percent CFC-113 and about 96.5 weight percent HFC-245fa and at a temperature of about 14.44° C. ± 0.3° C. and a pressure of about 14.29 psia ± 0.3 psia, as discussed in more detail in Section V. Such azeotropes are difficult to separate, as discussed in more detail in Section VI and Example 1. Avoiding the formation of an azeotrope or azeotrope-like mixture of CFC-113 and HFC-245fa can reduce yield losses by reducing excess purge of HFC-245fa.

[0041] To further reduce the level of CFC impurities, either system may optionally be coupled with several auxiliary separation units to reduce the amount of CFC-113 in the HFC-245fa feed (before intermediate distillation) and remove any residual CFC-114 from the HFO-1234ze(E) product.

[0042] An example of a generic HFO-1234ze(E) process is Figure 1 As shown therein, crude HFC-245fa enters the process via feed stream 10. Stream 10 is optionally passed through a separation unit 12 which initially reduces the CFC-113 content of the HFC-245fa feed via one of several unit operations as described below.

[0043] The composition in feed stream 10 may include HFC-245fa raw material and CFC-113 present as an impurity. Feed stream 10 may include CFC-113 in an amount greater than 0 ppm, such as 1 ppm or more, or as low as 5000 ppm or less, 4500 ppm or less, 4000 ppm or less, 3500 ppm or less, 3000 ppm or less, 2500 ppm or less, 2000 ppm or less, 1500 ppm or less, 1000 ppm or less, 900 ppm or less, 800 ppm or less, 700 ppm or less, 600 ppm or less, 500 ppm or less, 400 ppm or less, 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 20 ppm or less, 10 ppm or less, or in an amount of CFC-113 in any range encompassing any two of these values ​​as endpoints.

[0044] Separator 12 can be any separator suitable for reducing the content of CFC-113 in HFC-245fa. In one embodiment, the separator may include a zeolite that utilizes the structural or size differences between molecules. Suitable zeolites include sodium aluminosilicate, X-type zeolite, AW-500, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, activated carbon or carbon molecular sieve. In one embodiment, the separator may include a zeolite that utilizes the difference in dipole moment between molecules. In one embodiment, the separator may include an extractant to utilize the different solubility between molecules. Suitable extractants include but are not limited to pentane, hexane, ethyl acetate, dichloromethane, chloroform, tetrahydrofuran, methanol or water. In one embodiment, the separator may include an azeotropic distillation device. In one embodiment, the separator may include a knockout tank to remove oil from the desired component and an apparatus for passing the mixture through mineral oil with a gas phase at a sufficiently low speed to achieve the dissolution of undesirable CFC impurities in the mineral oil.

[0045] Stream 13 comprises CFC-113 which may be removed from the system for disposal.

[0046] Stream 14, also referred to herein as the first product stream, conveys the purified HFC-245fa to reactor 16 wherein the HFC-245fa is catalytically dehydrohalogenated to produce a product comprising HFO-1234ze(E) as described above.

[0047] The composition in stream 14 may comprise CFC-113 in an amount greater than 0 ppm, such as 1 ppm or more, or as low as 5000 ppm or less, 4500 ppm or less, 4000 ppm or less, 3500 ppm or less, 3000 ppm or less, 2500 ppm or less, 2000 ppm or less, 1500 ppm or less, 1000 ppm or less, 900 ppm or less, 800 ppm or less, 700 ppm or less, 600 ppm or less, 500 ppm or less, 400 ppm or less, 300 ppm or less, 200 ppm or less, 100 ppm or less, 50 ppm or less, 20 ppm or less, or 10 ppm or less, an amount greater than 0 ppm or 0 ppm, or in any range encompassing any two of these values ​​as endpoints.

[0048] Reactor 16 can be operated at a temperature as low as 300°F, 325°F, 350°F, 375°F, 400°F, 425°F, 450°F, 475°F, 500°F, 525°F, 550°F, or as high as 575°F, 600°F, 625°F, 650°F, 675°F, 700°F, 725°F, 750°F, 775°F, 800°F, or in any range encompassing any two of these values ​​as endpoints. Reactor 16 may also be operated at a pressure as low as 0 psia, 5 psia, 10 psia, 15 psia, 20 psia, 25 psia, 30 psia, 35 psia, 40 psia, 45 psia, 50 psia, or as high as 55 psia, 60 psia, 65 psia, 70 psia, 75 psia, 80 psia, 85 psia, 90 psia, 95 psia, 100 psia, or in any range encompassing any two of these values ​​as endpoints. The residence time in reactor 16 may be as low as 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 seconds, or as high as 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 seconds, or in any range encompassing any two of these values ​​as endpoints.

[0049] The dehydrofluorination catalyst may include chromium oxide, chromium oxyfluoride and chromium halide. The chromium oxide may include amorphous chromium oxide (Cr2O3), crystalline chromium oxide and combinations of the foregoing. The chromium oxyfluoride may include fresh amorphous chromium oxide (Cr2O3) pretreated with HF, fresh crystalline chromium oxide (Cr2O3) pretreated with HF, amorphous chromium oxyfluoride (CrO x F y , wherein x may be greater than 0 but less than 1.5, and y may be greater than 0 but less than 3), crystalline chromium oxyfluoride (CrO x F y , wherein x may be greater than 0 but less than 1.5, and y may be greater than 0 but less than 3) and combinations thereof. In one embodiment, the catalyst is amorphous chromium oxyfluoride (CrO x F y , wherein x may be greater than 0 but less than 1.5, and y may be greater than 0 but less than 3). The chromium halide may include chromium trifluoride (CrF3), chromium trichloride (CrCl3), chromium triiodide (CrI3) and chromium tribromide (CrBr3), and combinations thereof. In one embodiment, the catalyst is chromium trifluoride (CrF3).

[0050] Other suitable catalysts include promoted or doped chromium-based catalysts, also referred to as modified chromium-based catalysts, which are based on chromium and include a certain amount of at least one promoter or modifier selected from K, Na, Cu, Ni, Zn, Co, Mn, Mg or a mixture thereof. Based on the gross weight of the catalyst, the amount of the promoter or modifier can be between 0.1 wt % and 20 wt %, and more particularly, based on the gross weight of the catalyst, can be as low as 0.1 wt %, 0.5 wt %, 1.0 wt %, 1.5 wt % or as high as 2.0 wt %, 3.0 wt %, 4.0 wt %, 5.0 wt %, 6.0 wt % or in an amount in any range covering any two values ​​of these values ​​as endpoints. A suitable promoted chromium catalyst is a zinc / chromium oxide catalyst, which is based on chromium oxide and includes a certain amount of zinc as a promoter, for example, the JM 62-3M catalyst available from Johnson Matthey. Prior to use, the catalyst may be fluorinated using anhydrous HF under conditions effective to convert a portion of the metal oxide to the corresponding metal fluoride.

[0051] The chromium-based catalyst may also be a low chromium (VI) catalyst, wherein the total content of chromium (VI) oxide is about 5,000 ppm or less, about 2,000 ppm or less, about 1,000 ppm or less, about 500 ppm or less, about 250 ppm or less, or about 100 ppm or less, based on the total chromium oxide in the chromium oxide catalyst.

[0052] In addition to chromium-based catalysts, other suitable catalysts include aluminum oxide, iron oxide, magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, aluminum fluoride or metal fluoride, such as iron fluoride, magnesium fluoride, zinc fluoride, nickel fluoride, cobalt fluoride, fluorinated aluminum oxide, fluorinated iron oxide, fluorinated magnesium oxide, fluorinated nickel oxide, fluorinated cobalt oxide, titanium fluoride, molybdenum fluoride, aluminum oxyfluoride and combinations of the foregoing. Prior to use, the catalyst containing the metal oxide is fluorinated using anhydrous HF under conditions effective to convert a portion of the metal oxide into the corresponding metal fluoride. Halides of pentavalent antimony, niobium, arsenic and tantalum are commercially available, and their mixed halides are generated in situ when reacted with HF. Antimony pentachloride is preferred because of its low cost and availability. By the chemical formula SbCl n F 5-n The mixed halides of pentavalent antimony represented by are more preferred, wherein n is 0 to 5. The fluorination catalyst preferably has a purity of at least about 97%. Although the amount of fluorination catalyst used can vary widely, it is suitable to use about 5% to about 50%, or preferably about 10% to about 25% catalyst by weight relative to the organic.

[0053] After the dehydrofluorination reaction, crude product stream 18 is sent to separation unit 20 for HF removal.

[0054] The composition in stream 18 comprises a crude product of the reactor, which may include CFC-113, HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), CFC-114, light impurities, heavy impurities, and HF. HF may be present in stream 18 in an amount as low as 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, or as high as 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, or in any range encompassing any two of these values ​​as endpoints, based on the total weight of the stream composition.

[0055] Separation device 20 can be any separation device suitable for reducing the content of HF in the composition of feed stream 18. In one embodiment, HF can be recovered using a water or caustic scrubber or contact with a metal salt, such as potassium fluoride or sodium fluoride. In another embodiment, HF can be recovered by passing the composition through a sulfuric acid extractor, desorbing the extracted HF from sulfuric acid, and then distilling the desorbed hydrogen fluoride. When the mixture is in a liquid or gaseous state, separation can be performed by adding sulfuric acid to the mixture. In an alternative embodiment, HF can be recovered from the mixture in the gas phase by a continuous process of introducing a sulfuric acid stream into feed stream 18. This can be performed in a standard scrubber by flowing the sulfuric acid stream countercurrent to feed stream 18. In another embodiment, HF can be removed by adsorption onto a carbon molecular sieve, HF polymer gel, membrane or zeolite.

[0056] After removal of HF, stream 22 is condensed in condenser 24 to produce stream 26 .

[0057] The composition in stream 22 may comprise a crude product of the reactor including CFC-113, HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), CFC-114, light components, heavy components, and a reduced amount of HF. HF may be present in stream 22 in an amount of less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, less than 0.5 wt%, or less than 0.1 wt%.

[0058] Condenser 24 can be operated at a pressure as low as 0 psia, 10 psia, 20 psia, 30 psia, 40 psia, 50 psia, 60 psia, 70 psia or as high as 80 psia, 90 psia, 100 psia, 110 psia, 120 psia, 130 psia, 140 psia, 150 psia, or in any range encompassing any two of these values ​​as endpoints. Condenser 24 can be operated at a temperature as low as -20°C, -10°C, 0°C, 10°C, or as high as 20°C, 40°C, 50°C, 60°C, or in any range encompassing any two of these values ​​as endpoints.

[0059] Stream 26 is fed to separation unit 28 which separates the reaction mixture into stream 30 and a waste stream 52 comprising light impurities.

[0060] The term "light impurities" as used herein refers to impurities or azeotropes having a boiling point below -19°C, ie, a boiling point lower than that of HFO-1234ze(E). Examples of light impurities include, but are not limited to, 3,3,3-trifluoropropyne (TFPy), TFPy / water azeotrope, TFPy / HF azeotrope, HFO-1234ze(E) / water azeotrope, HFO-1234ze(E) / HF azeotrope, HFO-1234yf (2,3,3,3-tetrafluoropropene), HFC-245cb (1,1,1,2,2-pentafluoropropane), HFC-152a (1,1-difluoroethane), HFC-134a (1,1,1,2-tetrafluoroethane), HFC-125 (pentafluoroethane), HFO-1225ye(Z) (1,2,3,3,3,-pentafluoropropene), HFO-1234zc (1,1,3,3,3-pentafluoropropene), and HFO-1234zf (2,3,3,3-tetrafluoropropene).

[0061] The composition in stream 26 may include CFC-113, HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), CFC-114, light impurities, heavy impurities, and a reduced amount of HF. The amount of light impurities in stream 26 may be as low as 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, or as high as 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, or in any range encompassing any two of these values ​​as endpoints, based on the total weight of the stream composition.

[0062] Separation device 28 can be any device suitable for separating light impurities from the reaction mixture. Examples of suitable devices include, but are not limited to, batch or continuous fractionation columns, rotating belt distillation equipment, or wiped film evaporators. Waste stream 29 contains light impurities that can be removed from the reaction mixture.

[0063] Stream 30 is fed to separation unit 32 which provides a crude product stream 44 comprising HFO-1234ze(E) as well as stream 34 .

[0064] Stream 30 may include CFC-113, HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), CFC-114, reduced light impurities, heavy impurities, and reduced HF. The amount of light impurities in stream 30 may be less than 0.01 wt%, 0.009 wt%, 0.008 wt%, 0.007 wt%, 0.006 wt%, 0.005 wt%, 0.004 wt%, 0.003 wt%, 0.002 wt%, or 0.001 wt%.

[0065] Separation device 32 may be any separation device suitable for separating HFO-1234ze(E) from the mixture. Examples of suitable devices include, but are not limited to, a batch or continuous fractionation column, a rotating belt distillation apparatus, or a wiped film evaporator.

[0066] Stream 44, also referred to herein as the second product stream, is optionally fed to separation unit 46 which reduces the CFC-114 content to provide purified final product HFO-1234ze(E) in stream 48. Stream 47 comprises CFC-114 which may be removed from the system for disposal.

[0067] Stream 44 may comprise CFC-114 and HFO-1234ze(E). The amount of CFC-114 may be as low as 1000 ppm or less, 900 ppm or less, 800 ppm or less, 700 ppm or less, 600 ppm or less, 500 ppm or less, 400 ppm or less, 300 ppm or less, 200 ppm or less, 100 ppm or less, or 50 ppm or less.

[0068] Stream 48 is a purified product stream that may contain HFO-1234ze(E) and CFC-114 in amounts less than 0.001 wt%, less than 0.0005 wt%, or less than 0.00001 wt%.

[0069] Separator 46 may be any separator suitable for reducing the amount of CFC-114 in HFO-1234ze (E). In one embodiment, the separator may include a zeolite that utilizes structural or size differences between molecules. Suitable zeolites include sodium aluminosilicate, X-type zeolite, AW-500, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, activated carbon or activated carbon molecular sieve. In one embodiment, the separator may include a zeolite that utilizes dipole moment differences between molecules. In one embodiment, the separator may include an extractant to utilize different solubility between molecules. Suitable extractants include but are not limited to pentane, hexane, ethyl acetate, dichloromethane, chloroform, tetrahydrofuran, methanol or water. In one embodiment, the separator may include an azeotropic distillation device. In one embodiment, the separator may include a knockout tank to remove oil from the desired component and a device that passes the mixture through mineral oil in a gas phase at a sufficiently low speed to achieve the dissolution of undesirable CFC impurities in the mineral oil.

[0070] Stream 34, also referred to herein as the third product stream, is fed to distillation apparatus 36 which provides a bottoms stream comprising heavy impurities in stream 42 for removal, and an overhead recycle stream 50 which is fed back into the feed stream.

[0071] As used herein, the term "heavy impurities" refers to impurities or azeotropes having a boiling point above -19°C, i.e., a boiling point higher than that of HFO-1234ze(E). Examples of heavy impurities include, but are not limited to, HCFO-1233ze(E) (trans-1-chloro-3,3,3-trifluoropropene), HCFO-1233zd(Z) (cis-1-chloro-3,3,3-trifluoropropene), HCFC-244fa (3-chloro-1,1,1,3-tetrafluoropropane), and CFC-113.

[0072] Stream 34 may comprise CFC-113, HFC-245fa, and HFO-1234ze(Z), and less than 0.001 wt. % HFO-1234ze(E).

[0073] Distillation apparatus 36 can be used to separate and remove heavy impurities from the system. The use of apparatus 36 can be carried out in a continuous or intermittent process. Apparatus 36 can be operated at a pressure as low as 0 psia, 10 psia, 20 psia, 30 psia, 40 psia, 50 psia, 60 psia, 70 psia or as high as 80 psia, 90 psia, 100 psia, 110 psia, 120 psia, 130 psia, 140 psia, 150 psia or in any range covering any two of these values ​​as endpoints. Apparatus 36 can be operated at a temperature as low as 10°C, 20°C, 30°C, 40°C, 50°C or as high as 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or in any range covering any two of these values ​​as endpoints.

[0074] Waste stream 42 contains heavy impurities, such as CFC-113, which can be removed from the system as waste, wherein the amount of CFC-113 in stream 42 can be from 1 wt % or more, 2.5 wt % or more, 4 wt % or more, to 6 wt % or less, 7.5 wt % or less, or 10 wt % or less or in any range encompassing any two of these values ​​as endpoints.

[0075] The recycle stream 50 may comprise CFC-113, HFC-245fa, an azeotrope of CFC-113 and HFC245fa, HFO-1234ze(Z), and HFO-1234ze(E).

[0076] The heating system for the reactor and distillation may include any suitable heating medium capable of reaching and / or maintaining the temperature required for the process. For example, suitable heating medium may include molten salt, hot oil, steam, and electric heaters (resistance heating or induction heating), etc.

[0077] IV. Removal of CFC-113 from Recycle Streams

[0078] As shown in Example 2A below, it has been found that it is not necessary to focus solely on removing CFC-114 from the HFO-1234ze(E) product or removing CFC-113 from the HFC-245fa feed. Instead, CFC-113 can be purged from an intermediate stream of the process where separation is easier, allowing the use of smaller, cheaper equipment with lower energy consumption and lower yield losses. This intermediate stream is separated and distilled to provide a recycle stream comprising unconverted HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E) and a reduced amount of CFC-113, and a waste stream comprising impurities that can be removed from the system, which recycle stream can be fed back to the reactor.

[0079] As discussed further in Section VI below, CFC-113 and HFC-245fa have been found to form a uniform minimum boiling azeotrope at about 3.5 weight percent CFC-113 and about 96.5 weight percent HFC-245fa and at a temperature of about 14.44°C ± 0.3°C and a pressure of about 14.29 psia ± 0.3 psia.

[0080] This process follows that described in Section III and in Figure 1 The same process outlined in , but the CFC-113 content is allowed to accumulate in the recycle stream before being purged from the system. Due to the discovered azeotropic behavior of CFC-113 and HFC-245fa mixtures, it may be beneficial to remove CFC-113 from the recycle stream where CFC-113 has accumulated to 1 wt % or more, 1.5 wt % or more, 2 wt % or more, 2.5 wt % or more, 3 wt % or more, 3.5 wt % or more, 4 wt % or more, or 5 wt % or more. This approach strikes a balance between reducing CFC impurities to acceptable levels while minimizing unnecessary separations and reducing yield losses. Allowing the CFC-113 concentration to accumulate before removal avoids attempting to separate components at the pinch point of the CFC-113 and HFC-245fa mixture.

[0081] V. Separation at higher pressure

[0082] It has also been discovered that, as shown in Examples 2B and 5 below, the vapor-liquid equilibrium with respect to the formation of an azeotrope or azeotrope-like mixture of CFC-113 and HFC-245fa is pressure dependent, and that azeotropic behavior between CFC-113 and HFC-245fa can be substantially or completely avoided when a mixture comprising CFC-113 and HFC-245fa is exposed to pressures greater than about 17 psia, for example, by operating the separation stage of the process of the present invention at such elevated pressures to avoid the formation of an azeotrope.

[0083] Operating the CFC-113 and HFC-245fa separation steps at these higher pressures advantageously avoids the need to concentrate the CFC-113 in a recycle stream prior to removal as discussed in Section IV above. In addition, operating at higher pressures makes the final separation of CFC-113 and HFC-245fa easier because it avoids the formation of a CFC-113 / HFC-245fa azeotrope, allowing these components to be effectively separated based on the differences in their boiling points.

[0084] This process follows that described in Section III and in Figure 1The same process outlined in , but with a higher pressure in the distillation equipment, an increased amount of CFC-113 in the waste stream, and a reduced amount of CFC-113 in the recycle stream. All other parameters including reactor setup and temperature conditions were the same as described in Section III above.

[0085] Distillation apparatus 36 can operate at a pressure of 17 psia or more, 18 psia or more, 19 psia or more, 20 psia or more, 25 psia or more, 30 psia or more, 35 psia or more, 40 psia or more, 45 psia or more, 50 psia or more, 55 psia or more, 60 psia or more, 65 psia or more, 70 psia or more, 75 psia or more, 80 psia or more, 85 psia or more, 90 psia or more, 95 psia or more, 100 psia or more, 105 psia or more, 110 psia or more, 115 psia or more, 120 psia or more, 125 psia or more, 130 psia or more, 135 psia or more, 140 psia or more, 145 psia or more, or 150 psia or more, or in any range encompassing any two of these values ​​as endpoints.

[0086] Waste stream 42 comprises heavy impurities, such as CFC-113, which can be removed from the system as waste, wherein the amount of CFC-113 in stream 42 can be 1 wt % or more, 2 wt % or more, 3 wt % or more, 4 wt % or more, 5 wt % or more, 6 wt % or more, 7 wt % or more, 8 wt % or more, 9 wt % or more, 10 wt % or more, 15 wt % or more, 20 wt % or more, 25 wt % or more, 30 wt % or more, 35 wt % or more, 40 wt % or more, 45 wt % or more, 50 wt % or more, 55 wt % or more, 60 wt % or more, 65 wt % or more, 70 wt % or more, 75 wt % or more, 80 wt % or more, 85 wt % or more, 90 wt % or more, 95 wt % or more, 100 wt %, or in any range encompassing any two of these values ​​as endpoints.

[0087] The recycle stream 50 may include CFC-113, HFC-245fa, an azeotrope of CFC-113 and HFC245fa, HFO-1234ze(Z), and HFO-1234ze(E). The amount of CFC-113 in the recycle stream may be 10 wt% or less, 9 wt% or less, 8 wt% or less, 7 wt% or less, 6 wt% or less, 5 wt% or less, 4 wt% or less, 3 wt% or less, 2 wt% or less, 1 wt% or less, 0.5 wt% or less, 0.1 wt% or less, or in any range encompassing any two of these values ​​as endpoints.

[0088] VI. Azeotropic Compositions Comprising HFC-245fa and CFC-113

[0089] The inventors have experimentally found that HFC-245fa and CFC-113 form azeotropes or azeotrope-like compositions at pressures lower than 25 psia. The discovery of this azeotropic mixture is related to the process of converting HFC-245fa into HFO-1234ze (E). CFC-113 is an undesirable impurity that can be found in the HFC-245fa feedstock and can be converted into CFC-114 during the dehydrofluorination reaction to produce HFO-1234ze (E). Therefore, a method for separating a mixture of HFC-245fa and CFC-113 is needed to prevent the accumulation of CFCs in the whole HFO-1234ze (E) process.

[0090] An "azeotrope" composition is a unique combination of two or more components. Azeotrope compositions can be characterized in various ways. For example, at a given pressure, an azeotrope composition boils at a constant characteristic temperature that is either higher than the higher boiling component (maximum boiling azeotrope) or lower than the lower boiling component (minimum boiling azeotrope). At this characteristic temperature, the same composition will exist in both the gas phase and the liquid phase. Azeotrope compositions do not fractionate when boiling or evaporating. Therefore, the components of an azeotrope composition cannot be separated during a phase change.

[0091] Azeotrope compositions are also characterized in that, at the characteristic azeotrope temperature, the bubble point pressure of the liquid phase is the same as the dew point pressure of the vapor phase.

[0092] The behavior of azeotropic compositions is in contrast to the behavior of zeotropic compositions, in which the liquid composition changes to a considerable extent during boiling or evaporation.

[0093] For purposes of this disclosure, an azeotrope composition is characterized in that it boils at a constant characteristic temperature that is below the boiling points of two or more components (the minimum boiling azeotrope) and thus has the same composition in both the vapor and liquid phases.

[0094] However, it will be appreciated by those of ordinary skill in the art that the composition and boiling point of an azeotrope composition will vary to some extent at different pressures. Thus, depending on the temperature and / or pressure, an azeotrope composition may have a varying composition. Thus, it will be appreciated by those of ordinary skill in the art that a range of compositions rather than fixed compositions may be used to define an azeotrope composition. Additionally, an azeotrope may be defined based on the exact weight percentage of each component of a composition characterized by a fixed boiling point at a specified pressure.

[0095] An "azeotrope-like" composition is a composition of two or more components that behaves essentially like an azeotrope composition. Thus, for purposes of this disclosure, an azeotrope-like composition is a combination of two or more different components that, when in liquid form at a given pressure, will boil at a substantially constant temperature and which will provide a vapor composition that is substantially the same as the liquid composition undergoing boiling.

[0096] For purposes of this disclosure, an azeotrope or azeotrope-like composition comprising HFC-245fa and CFC-113 is a composition or compositions that boils within a temperature range of about 14.44°C ± 0.3°C and a pressure of about 14.29 psia ± 0.3 psia.

[0097] Azeotropes or azeotrope-like compositions can be identified using a variety of different methods. For the purposes of this disclosure, azeotropes or azeotrope-like compositions are identified experimentally using an ebulliometer (Walas, Phase Equilibria in Chemical Engineering, Butterworth-Heinemann, 1985, 533-544). Ebulliometers are designed to measure the boiling point of a liquid extremely accurately by measuring the temperature of vapor-liquid equilibrium.

[0098] The boiling points of each component alone are measured at a constant pressure. The skilled person will know that for a binary azeotrope or azeotrope-like composition, the boiling point of one of the components of the composition is initially measured. The second component of the composition is then added in varying amounts, and the boiling point of each of the resulting compositions is measured at said constant pressure using an ebulliometer.

[0099] The measured boiling points are plotted against the composition of the composition tested, e.g., for a binary azeotrope, the amount of the second component added to the composition (expressed in weight % or mole %). The presence of an azeotrope composition can be identified by observing a maximum or minimum boiling temperature that is higher or lower than the boiling point of any individual component.

[0100] The skilled artisan will appreciate that azeotropes or azeotrope-like compositions are identified by comparing the change in boiling point of the composition relative to the boiling point of the first component when a second component is added to the first component. Thus, in order to measure the change in boiling point, it is not necessary to calibrate the system to the reported boiling point of a specific component.

[0101] As previously stated, at the highest or lowest boiling point, the composition of the vapor phase will be the same as the composition of the liquid phase. Thus, an azeotrope-like composition is one that provides a substantially constant lowest or highest boiling point component, i.e., a boiling point of about 14.44°C ± 0.3°C at a pressure of about 14.29 psia ± 0.3 psia, at which substantially constant boiling point, the composition of the vapor phase will be substantially the same as the composition of the liquid phase.

[0102] An azeotrope or azeotrope-like composition having a boiling point of about 14.44°C ± 0.3°C at a pressure of about 14.29 psia ± 0.3 psia comprises, consists essentially of, or consists of about 1 wt % to about 15 wt % CFC-113, about 1 wt % to about 10 wt % CFC-113, about 1 wt % to about 5 wt % CFC-113, or about 3.5 wt % CFC-113 and about 85 wt % to about 99 wt % HFC-245fa, about 90 wt % to about 99 wt % HFC-245fa, about 95 wt % to about 99 wt % HFC-245fa, or about 96.5 wt % HFC-245fa.

[0103] In other words, an azeotrope or azeotrope-like composition having a boiling point of about 14.44°C ± 0.3°C at a pressure of about 14.29 psia ± 0.3 psia comprises, consists essentially of, or consists of about 1 wt % to about 15 wt % CFC-113 and about 85 wt % to about 99 wt % HFC-245fa, or about 1 wt % to about 10 wt % CFC-113 and about 90 wt % to about 99 wt % HFC-245fa, or about 1 wt % to about 5 wt % CFC-113 and about 95 wt % to about 99 wt % HFC-245fa, or about 3.5 wt % CFC-113 and about 96.5 wt % HFC-245fa.

[0104] In other words, an azeotrope or azeotrope-like composition having a boiling point of about 14.44°C ± 0.3°C at a pressure of about 14.29 psia ± 0.3 psia comprises, consists essentially of, or consists of as little as about 1 wt %, CFC-113, or up to about 5 wt %, about 10 wt %, or about 15 wt % CFC-113, or within any range defined between any two of the foregoing values, and an azeotrope or azeotrope-like composition comprises, consists essentially of, or consists of as little as about 85 wt %, about 90 wt %, about 95 wt % HFC-245fa, or up to about 99 wt % HFC-245fa, or within any range defined between any two of the foregoing values.

[0105] The azeotrope or azeotrope-like composition of the present disclosure has a boiling point of about 14.44°C ± 0.3°C at a pressure of about 14.29 psia ± 0.3 psia.

[0106] It has also been found that azeotropes or azeotrope-like compositions are pressure dependent. Constant minimum or maximum boiling point behavior is observed at pressures below about 17 psia, and no azeotrope or azeotrope-like behavior is observed at pressures above about 17 psia.

[0107] For example, an azeotrope or azeotrope-like composition can exist at a pressure of less than about 17 psia, such as 16 psia or less, 15 psia or less, 14 psia or less, 13 psia or less, 12 psia or less, 11 psia or less, 10 psia or less, 9 psia or less, 8 psia or less, 7 psia or less, 6 psia or less, 5 psia or less, 4 psia or less, 3 psia or less, 2 psia or less, 1 psia or less, or in any range encompassing any two of the foregoing values ​​as endpoints.

[0108] An azeotrope or azeotrope-like composition may not exist at a pressure greater than about 17 psia, such as 18 psia or more, 19 psia or more, 20 psia or more, 21 psia or more, 22 psia or more, 23 psia or more, 24 psia or more, 25 psia or more, 26 psia or more, 27 psia or more, 28 psia or more, 29 psia or more, 30 psia or more, 31 psia or more, 32 psia or more, 33 psia or more, 34 psia or more, 35 psia or more, 36 psia or more, or in any range encompassing any two of the foregoing values ​​as endpoints.

[0109] As used herein, the phrase "within any range that includes any two of the preceding values ​​as endpoints" literally means that any range can be selected from any two values ​​listed before such phrase, regardless of whether these values ​​are in the lower part of the list or in the upper part of the list. For example, a pair of values ​​can be selected from two lower values, two higher values, or a lower value and an upper value.

[0110] Example

[0111] Example 1 - Ebulliometer Study

[0112] Azeotropes and azeotrope-like compositions of HFC-245fa and CFC-113 are measured using an ebulliometer. The ebulliometer comprises a vacuum-jacketed glass container that is sealed at the bottom and open to the atmosphere at the top. The top or condenser jacket of the ebulliometer is filled with a mixture of dry ice and ethanol at a pressure of 14.40 psia to obtain a temperature of about -72°C, which is significantly lower than the standard boiling points of 15.3°C for 1,1,1,3,3-pentafluoropropane (HFC-245fa) and 47.5°C for 1,1,2-trichloro-trifluoroethane (CFC-113). In this way, it is ensured that all vapors in the system are condensed and flow back into the ebulliometer so that the liquid and vapor phases are in equilibrium. A quartz-platinum thermometer with an accuracy of ±0.002°C is inserted into the glass container and used to determine the temperature of the condensed vapor corresponding to the equilibrium boiling point of the mixture. Zeolites are used to help keep the mixture boiling steadily in the ebulliometer.

[0113] Use the following procedure:

[0114] 1. Immerse a quartz thermometer in a long Dewar containing an ice / water slurry and verify that the thermometer reads 0°C. The Dewar is deep enough so that at least 3 / 4 of the length of the thermometer shaft is submerged in the ice / water. Record the thermometer resistance in ohms.

[0115] 2. Fill the condenser jacket to 1 / 4 full with ethanol. Cool the condenser jacket by slowly introducing dry ice to avoid boiling over and / or splashing of the ethanol.

[0116] 3. Add a known amount of CFC-113 or HFC-245fa to the ebulliometer and bring to vigorous reflux conditions. Record the temperature and atmospheric pressure using a barometer with a temperature indicator.

[0117] The measurement is carried out in two steps. In the first step, about 24.50 g of CFC-113 (99.88 area % purity as determined by gas chromatography (GC)) is first introduced into the ebulliometer by weighing the container before and after addition using a balance with an accuracy of ±0.01 g. The liquid is boiled and the equilibrium temperature of CFC-113 at the recorded gas pressure is recorded. Then, HFC-245fa (99.99 area % purity as determined by gas chromatography (GC)) is introduced into the ebulliometer in small increments and the equilibrium temperature of the condensed liquid mixture is recorded.

[0118] In the second step, about 16.09 g of HFC-245fa (99 area % purity as determined by gas chromatography (GC)) was introduced into the ebulliometer by weighing the container before and after addition using a balance with an accuracy of ±0.01 g. The liquid was boiled and the equilibrium temperature of HFC-245fa at the recorded pressure was recorded. Then, CFC-113 (99.88 area % purity as determined by gas chromatography (GC)) was introduced into the ebulliometer in small increments and the equilibrium temperature of the condensed liquid mixture was recorded.

[0119] The data from the first and second steps described above were combined to complete the composition range data for each of HFC-245fa and CFC-113 given in Table 2 below, which shows the minimum temperature indicating that an azeotrope has been formed, and which data is also shown in graphical form at Figure 2 The data show that a weak minimum azeotrope forms at about 3.5 wt% CFC-113 at a pressure of 14.29 Psia. The azeotropic temperature is 14.44°C, which is lower than the boiling point of HFC-245fa.

[0120] Table 2

[0121] Ebulliometric Study of HFC-245fa / CFC-113 at P = 14.29 Psia

[0122] T(℃) Weight % of HFC-245fa CFC-113 weight% 14.47 100.00 0.00 14.46 99.26 0.74 14.45 98.26 1.74 14.44 96.45 3.55 14.45 94.59 5.41 14.52 91.13 8.87 14.60 87.70 12.30 14.69 84.52 15.48 14.90 78.22 21.78 15.10 72.76 27.24 15.26 68.17 31.83 15.41 64.09 35.91 15.51 60.43 39.57 15.55 57.07 42.93 15.71 53.48 46.52 15.61 49.49 50.51 15.64 46.27 53.73 15.81 43.20 56.80 15.86 38.77 61.23 16.01 34.30 65.70 16.08 29.80 70.20 16.29 26.40 73.60 16.44 21.92 78.08 16.43 17.15 82.85 16.49 13.63 86.37 16.76 9.61 90.39 17.92 5.07 94.93 45.37 1.63 98.37 46.82 0.00 100.00

[0123] Example 2A - Removal of CFC-113 from HFO-1234ze(E) by purging CFC-113 from a recycle stream 114 Method

[0124] Example 2A provides Figure 1 Material balance for each stream in the depicted process.

[0125] Table 3

[0126] Figure 1 Material balance .

[0127]

[0128] like Figure 1 As shown, CFC-113 impurities are removed from the recycle stream of the HFC-245fa to HFO-1234ze (E) process via distillation at a pressure below 17 psia. The recycle stream 50 mainly contains unconverted HFC-245fa, HFO-1234ze (Z), 1234ze (E) and CFC-113. Due to the difficulties involved in separating CFC-113 from HFC-245fa, it is beneficial to remove 113 from the recycle stream, in which the component has accumulated to 1% by weight or more. Because CFC-113 is a high boiling impurity, it can be removed in the heavy impurity removal stream 42.

[0129] Example 2B - Process for Removing CFC-114 from HFO-1234ze(E) by Operating at Higher Pressure

[0130] Example 2B provides Figure 1 Material balance for each stream in the depicted process. Example 2B differs from Example 2A in that the removal of CFC-113 via distillation (block 36 ) is performed at a pressure above 17 psia, which does not require accumulation of 113 in recycle stream 50 .

[0131] Table 4

[0132] Figure 1 Material balance .

[0133]

[0134] like Figure 1 As shown, CFC-113 impurities are removed from the recycle stream of the HFC-245fa to HFO-1234ze (E) process via distillation at a pressure higher than 17 psia. The recycle stream 50 mainly comprises unconverted HFC-245fa, HFO-1234ze (Z), 1234ze (E) and CFC-113. Because the azeotrope between 113 and 245fa does not exist at this pressure, it is not necessary to increase 113 to 1 weight % or higher. This reduces the amount of 113 fed to the reactor and the amount of 114 produced by the reactor (frame 16). Because CFC-113 is a high boiling impurity, it can be removed in the heavy impurity removal stream 42.

[0135] Example 3 - Separation of CFC-113 / HFC-245fa mixture

[0136] Example 3A - Adsorbent

[0137] Re-reference Figure 1, CFC-113 is removed from a stream comprising CFC-113 and HFC-245fa by passing the stream through an adsorption unit comprising a molecular sieve. Thus, the amount of CFC-113 is reduced to an acceptable level for the HFC-245fa feed stream.

[0138] Example 3B - Liquid Extraction

[0139] Re-reference Figure 1 , CFC-113 is removed from a stream containing CFC-113 and HFC-245fa by liquid extraction using a mixture of hexane and ethyl acetate. Thus, the amount of CFC-113 is reduced to an acceptable level for the HFC-245fa feed stream.

[0140] Example 3C - Mineral Oil Extraction

[0141] Re-reference Figure 1 , remove CFC-113 from the feed stream comprising CFC-113 and HFC-245fa by mineral oil extraction.The feed stream of HFC-245fa comprising 0.50 % by weight of CFC-113 is evaporated and fed to the bottom of the packed tower at a feed rate of about 2.2 pounds / hour, lasting about 4 hours.In the same time range, the feed stream of mineral oil is continuously fed to the top of the same packed tower at a feed rate of about 3.5 pounds / hour.The gaseous feed stream leaving the tower top comprises the HFC-245fa of the CFC-113 less than 0.10 % by weight.The concentration of CFC-113 in the mineral oil is increased to about 0.25 % by weight from being unable to be detected.

[0142] Example 4 - Separation of a CFC-114 / HFO-1234ze(E) mixture

[0143] Example 4A - Adsorbent

[0144] Re-reference Figure 1 , CFC-114 is removed from a stream comprising CFC-114 and HFO-1234ze(E) by passing the stream through an adsorption unit comprising a molecular sieve. Thus, the amount of CFC-114 is reduced to an acceptable level for the HFO-1234ze(E) product stream.

[0145] Example 4B - Liquid Extraction

[0146] Re-reference Figure 1 , CFC-114 is removed from a stream containing CFC-114 and HFO-1234ze(E) by liquid extraction using a mixture of hexane and ethyl acetate. Thus, the amount of CFC-114 is reduced to an acceptable level for the HFO-1234ze(E) product stream.

[0147] Example 4C - Mineral Oil Extraction

[0148] Re-reference Figure 1 , remove CFC-114 from the feed stream comprising CFC-114 and HFO-1234ze (E) by mineral oil extraction. The feed stream of HFO-1234ze (E) containing 0.20% by weight of CFC-114 impurities is evaporated and fed to the bottom of the packed tower at a feed rate of about 2.1 pounds per hour for about 4 hours. In the same time range, the feed stream of mineral oil is continuously fed to the top of the same packed tower at a feed rate of about 3.3 pounds per hour. The gaseous feed stream leaving the tower top contains HFO-1234ze (E) less than 0.050% by weight of CFC-114. The concentration of CFC-114 in the mineral oil increases to about 0.095% by weight from being unable to be detected.

[0149] Example 5 - Ebulliometer Study of HFC-245fa and CFC-113 Mixtures at Different Pressures

[0150] HFC-245fa and CFC-113 were tested in an isobaric ebulliometer. A pressure controller was used to set the pressure and an RTD was used to measure the temperature. Charges and additions were made volumetrically by pumps. The following data sets are the results of these experiments. The conclusion is that the azeotrope composition changes with pressure and is expected to break above 20.4 psia.

[0151] Table 5. HFC-245fa and CFC-113 compositions and measurement temperatures

[0152]

[0153] These data are plotted in Figures 3 to 5 middle. Figure 3 The minimum azeotrope boiling point at 92.20 wt % HFC-245fa at a pressure of 5 Psia is shown. Figure 4 The minimum azeotrope boiling point at 95.01 wt % HFC-245fa at a pressure of 10 Psia is shown. Figure 5 The minimum azeotrope boiling point is shown at 97.01 wt % HFC-245fa at a pressure of 14.7 Psia.

[0154] along with Figures 3 to 5 With increasing pressure, the azeotropic behavior becomes weaker, indicating that the azeotropic behavior between HFC-245fa and CFC-113 is pressure dependent. Figure 6 The azeotrope composition of HFC-245fa (mass %) is plotted against pressure and shows that the locus of the azeotrope shifts with pressure.

[0155] aspect

[0156] Aspect 1 is a method for producing HFO-1234ze(E), the method comprising: reacting a feed stream comprising HFC-245fa and CFC-113 in a reactor in the presence of a catalyst to form a first product stream comprising HFO-1234ze(E), unreacted HFC-245fa and CFC-113; separating the first product stream into a second product stream comprising HFO-1234ze(E) and a third product stream comprising unreacted HFC-245fa and CFC-113; distilling the third product stream to produce an overhead recycle stream and a bottoms stream, the recycle stream comprising unreacted HFC-245fa and a first amount of CFC-113, and the bottoms stream comprising a second amount of CFC-113 greater than the first amount; and conveying the recycle stream back to the feed stream.

[0157] Aspect 2 is a method according to aspect 1, wherein the distillation is carried out at a pressure greater than 17 psia.

[0158] Aspect 3 is a method according to aspect 1 or 2, wherein the recycle stream comprises less than 3 wt% CFC-113.

[0159] Aspect 4 is a method according to any one of aspects 1 to 3, wherein the distilling step comprises distilling the third product stream when the amount of CFC-113 is 1 wt% or greater based on the total weight of the third product stream.

[0160] Aspect 5 is a method according to any one of aspects 1 to 4, wherein the amount of CFC-113 in the recycle stream is 5 wt% or less based on the total weight of the recycle stream.

[0161] Aspect 6 is a method according to any one of aspects 1 to 5, wherein the first product stream further comprises hydrogen fluoride (HF) and is conveyed to a separation device to remove HF before entering the distillation device to remove CFC-113.

[0162] Aspect 7 is a method according to aspect 6, wherein the separation device comprises at least one of a water or caustic scrubber, a metal salt, a sulfuric acid extractor, a vapor phase sulfuric acid extractor, a distillation column, and a combination of the foregoing.

[0163] Aspect 8 is a method according to any one of aspects 1 to 7, wherein the first product stream further comprises light impurities, the light impurities comprising 3,3,3-trifluoropropyne (TFPy), TFPy / water azeotrope, TFPy / HF azeotrope, HFO-1234ze(E) / water azeotrope, HFO-1234ze(E) / HF azeotrope, HFO-1234yf (2,3,3,3-tetrafluoropropylene), HFC-245cb (1,1,1,2,2-pentafluoropropane), HFC-152a (1,1- At least one of HFC-227 (1,2,3,3,3-pentafluoropropylene), HFC-1234zc (1,1,3,3,3-pentafluoropropylene), or HFO-1234zf (2,3,3,3-tetrafluoropropylene) and a combination of the foregoing, and the first product stream is conveyed to a separation device to remove the light impurities before entering the distillation equipment to remove CFC-113.

[0164] Aspect 9 is the method according to aspect 8, wherein the separation device comprises at least one of a batch or continuous fractionation column, a rotating belt distillation apparatus, a wiped film evaporator, and a combination of the foregoing.

[0165] Aspect 10 is a method according to aspect 8, wherein the content of light impurities is reduced to 1 wt% or less based on the total weight of the intermediate stream.

[0166] Aspect 11 is the method according to any one of aspects 1 to 10, wherein the reactor is operated under at least one of the following conditions:

[0167] (i) a temperature of about 205°C to 370°C;

[0168] (ii) a pressure of about -15 psia to 100 psia; and

[0169] (iii) a residence time of about 1 second to 100 seconds.

[0170] Aspect 12 is a method according to aspect 1, wherein the distillation apparatus is operated under at least one of the following conditions:

[0171] (i) a temperature of about 10°C to 105°C and

[0172] (ii) a pressure of about -15 psia to 150 psia

[0173] Aspect 13 is a method for removing CFC-113 from an HFC-245fa feed stream in the production of HFO-1234ze(E), the method comprising: feeding HFC-245fa to a separation device, wherein the HFC-245fa also contains a first amount of CFC-113; recovering a purified HFC-245fa stream from the separation device, wherein the purified HFC-245fa stream has a second amount of CFC-113 less than the first amount.

[0174] Aspect 14 is a method according to aspect 13, wherein the separation device comprises at least one of zeolite, a liquid extractant, an azeotropic distillation apparatus, mineral oil, and a combination of the foregoing.

[0175] Aspect 15 is a method according to aspect 13, wherein the purified HFC-245fa stream comprises less than 0.05 wt% CFC-113 based on the total weight of the purified HFC-245fa stream.

[0176] Aspect 16 is a method for removing CFC-114 from an HFO-1234ze(E) product stream in an HFO-1234ze(E) process, the method comprising: feeding HFO-1234ze(E) to a separation device, the HFO-1234ze(E) also comprising a first amount of CFC-114; recovering a purified HFO-1234ze(E) stream from the separation device, the purified HFO-1234ze(E) stream having a second amount of CFC-114 less than the first amount.

[0177] Aspect 17 is a method according to aspect 16, wherein the separation device comprises at least one of zeolite, a liquid extractant, an azeotropic distillation apparatus, mineral oil, and a combination of the foregoing.

[0178] Aspect 18 is a method according to aspect 16, wherein the purified HFO-1234ze(E) stream contains less than 0.01 wt% CFC-114.

[0179] Aspect 19 is a composition comprising an azeotrope or azeotrope-like composition consisting essentially of effective amounts of CFC-113 and HFC-245fa.

[0180] Aspect 20 is a composition according to aspect 19, wherein the azeotrope or azeotrope-like composition consists essentially of about 3.5 weight percent CFC-113 and about 96.5 weight percent HFC-245fa.

[0181] It should be understood that the above description is merely an illustration of the present disclosure. Without departing from the present disclosure, those skilled in the art may design various alternatives and modifications. Therefore, the present disclosure is intended to cover all such alternatives, modifications and variations that fall within the scope of the appended claims.

Claims

1. A method for producing HFO-1234ze(E), the method comprising: reacting a feed stream comprising HFC-245fa and CFC-113 in a reactor in the presence of a catalyst to form a first product stream comprising HFO-1234ze(E), unreacted HFC-245fa, and CFC-113; separating the first product stream into a second product stream comprising HFO-1234ze(E) and a third product stream comprising unreacted HFC-245fa and CFC-113; distilling the third product stream to produce an overhead recycle stream and a bottoms stream, the recycle stream comprising unreacted HFC-245fa and a first amount of CFC-113, and the bottoms stream comprising a second amount of CFC-113 greater than the first amount; as well as The recycle stream is conveyed back to the feed stream.

2. The process of claim 1, wherein the distillation is carried out at a pressure greater than 17 psia.

3. The process of claim 1 wherein the recycle stream comprises less than 3 wt% CFC-113.

4. The method of claim 1, wherein the distilling step comprises distilling the third product stream when the amount of CFC-113 is 1 wt% or greater based on the total weight of the third product stream.

5. The process of claim 1 wherein the amount of CFC-113 in the recycle stream is 5 wt% or less based on the total weight of the recycle stream.

6. The process of claim 1 wherein the first product stream additionally comprises hydrogen fluoride (HF) and is sent to a separation unit to remove HF prior to entering a distillation unit to remove CFC-113.

7. The method of claim 6, wherein the separation device comprises at least one of a water or caustic scrubber, a metal salt, a sulfuric acid extractor, a vapor phase sulfuric acid extractor, a distillation column, and combinations of the foregoing.

8. The process of claim 1, wherein the first product stream further comprises light impurities, the light impurities comprising 3,3,3-trifluoropropyne (TFPy), TFPy / water azeotrope, TFPy / HF azeotrope, HFO-1234ze(E) / water azeotrope, HFO-1234ze(E) / HF azeotrope, HFO-1234yf (2,3,3,3-tetrafluoropropylene), HFC-245cb (1,1,1,2,2-pentafluoropropane), HFC-152a (1,1-difluoroethane), At least one of HFC-127a (1,1,1,2-tetrafluoroethane), HFC-134a (1,1,1,2-tetrafluoroethane), HFC-125 (pentafluoroethane), HFO-1225ye(Z) (1,2,3,3,3,-pentafluoropropylene), HFO-1234zc (1,1,3,3,3-pentafluoropropylene), or HFO-1234zf (2,3,3,3-tetrafluoropropylene) and a combination of the foregoing substances, and the first product stream is conveyed to a separation device to remove the light impurities before entering the distillation equipment to remove CFC-113.

9. The process of claim 8, wherein the separation device comprises at least one of a batch or continuous fractionation column, a rotating belt distillation apparatus, a wiped film evaporator, and combinations of the foregoing.

10. The method according to claim 8, wherein the content of light impurities is reduced to 1 wt% or less based on the total weight of the intermediate stream.

11. The process of claim 1, wherein the reactor is operated under at least one of the following conditions: (i) a temperature of about 205°C to 370°C; (ii) a pressure of about -15 psia to 100 psia; and (iii) a residence time of about 1 second to 100 seconds.

12. A process for removing CFC-113 from a HFC-245fa feed stream in the production of HFO-1234ze(E), the process comprising: feeding HFC-245fa to a separation unit, the HFC-245fa also comprising a first amount of CFC-113; A purified HFC-245fa stream is recovered from the separation unit, the purified HFC-245fa stream having a second amount of CFC-113 less than the first amount.

13. The process of claim 12, wherein the purified HFC-245fa stream comprises less than 0.05 wt% CFC-113 based on the total weight of the purified HFC-245fa stream.

14. A composition comprising an azeotrope or azeotrope-like composition consisting essentially of effective amounts of CFC-113 and HFC-245fa.

15. The composition of claim 14 wherein the azeotrope or azeotrope-like composition consists essentially of about 3.5 weight percent CFC-113 and about 96.5 weight percent HFC-245fa.

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