Method for reducing chlorofluorocarbon impurities in the production of trans-1,3,3,3-tetrafluoropropene (HFO-1234ze(E))

Abstract

Two methods for reducing CFC impurities, and specifically CFC-114, from the reaction of CFC-113 and HF in the HFO-1234ze(E) production process. The first method involves subjecting an intermediate or recycle stream to separation and distillation to purge CFC-113 from the process. The second method involves operating the separation at a higher pressure to avoid the formation of an azeotrope between CFC-113 and HFC-245fa. Also discussed are additional optional processes for the removal or reduction of CFC-113, including the removal of CFC-114 from the HFO-1234ze(E) product and / or the removal of CFC-113 from the HFC-245fa feed to produce an HFO-1234ze(E) product that contains little or no CFC-114 and other CFC impurities.

Description

Technical Field

[0001] (Cross - reference to related applications) This application is an international application of U.S. Patent Application Publication No. 18 / 218,691, filed on July 6, 2023, and claims priority to U.S. Provisional Patent Application No. 63 / 389,174, filed on July 14, 2022, and U.S. Provisional Patent Application No. 63 / 415,457, filed on October 12, 2022, all of which are hereby incorporated by reference in their entirety.

[0002] (Field of the Invention) The present disclosure is directed to a method for reducing the amount of chlorofluorocarbon impurities in a process for generating trans - 1,3,3,3 - tetrafluoropropene (HFO - 1234ze(E)).

Background Art

[0003] Chlorofluorocarbons (CFCs) have found wide use in a number of applications, including refrigerants, aerosol propellants, foaming agents, heat transfer media, gaseous dielectrics, and flame suppressants. In recent years, there has been widespread concern that certain chlorofluorocarbons can be harmful to the Earth's ozone layer. Therefore, efforts have been made worldwide to use halocarbons with few or no chlorine substituents. Thus, the production of hydrofluorocarbons, as well as compounds containing only carbon, hydrogen, and fluorine, is of increasing interest as starting materials for providing environmentally desirable products for use as solvents, foaming agents, refrigerants, cleaners, aerosol propellants, heat transfer media, dielectrics, fire - extinguishing compositions, power cycle working fluids, and hydrofluoroolefins (HFOs) that do not harm the ozone layer and have a low global warming potential.

Summary of the Invention

[0004] The present disclosure is based on the discovery that in the HFO-1234ze(E) production process, CFC impurities, and specifically CFC-114, are formed from the reaction of CFC-113 with HF. It has been found that by subjecting an intermediate or recycle stream to separation and distillation to purge CFC-113 from the process, the amount of such CFC impurities can be reduced. It has also been found that the amount of CFC impurities can be reduced by operating the separation at a higher pressure to avoid an azeotrope formed between CFC-113 and HFC-245fa. Other optional processes for the removal or reduction of CFC-113 include further separation to remove CFC-114 from the HFO-1234ze(E) product and / or CFC-113 from the HFC-245fa feed to produce an HFO-1234ze(E) product that contains little CFC-114 and other CFC impurities.

[0005] In one form, the present disclosure is a process for producing HFO-1234ze(E), 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 containing HFO-1234ze(E) and a third product stream containing unreacted HFC-245fa and CFC-113; distilling the third product stream to produce a top recycle stream and a bottoms stream, wherein the recycle stream contains unreacted HFC-245fa and a first amount of CFC-113 and the bottoms stream contains a second amount of CFC-113 that is greater than the first amount; and transferring the recycle stream back to the feed stream.

[0006] In a further aspect, the present disclosure provides a process for removing CFC-113 from an HFC-245fa feed stream in the production of HFO-1234ze(E), the process comprising: supplying HFC-245fa, which further comprises a first amount of CFC-113, to a separation device; and recovering from the separation device a purified HFC-245fa stream having a second amount of CFC-113 that is less than the first amount.

[0007] In a further aspect, the present disclosure provides a process for removing CFC-114 from an HFO-1234ze(E) production stream in an HFO-1234ze(E) process, the process comprising: supplying HFO-1234ze(E), which further comprises a first amount of CFC-114, to a separation device; and recovering from the separation device a purified HFO-1234ze(E) stream having a second amount of CFC-114 that is less than the first amount.

[0008] In a further aspect, the present disclosure provides an azeotropic or azeotrope-like composition comprising CFC-113 and HFC-245fa. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Reference will now be made to the following description of embodiments of the disclosure, taken in conjunction with the accompanying drawings, in which: the above and other features of the disclosure and the manner of attaining them will become more apparent, and the disclosure itself will be better understood.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0010] The examples described herein are illustrative of embodiments of the present disclosure and should not be construed as limiting the scope of the present disclosure in any way.

DETAILED DESCRIPTION OF THE INVENTION

[0011] I. Definitions

[0012]

Table 1

[0013] 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.

[0014] Unless otherwise specified, the term "HFO-1234ze" refers to both HFO-1234ze(E) and HFO-1234ze(Z) together.

[0015] II. Method for Reducing CFC-114 in HFO-1234ze(E) The present disclosure is based on the discovery that in the HFO-1234ze(E) production process, CFC-114 and CFC-114a are formed from the reaction of CFC-113 and CFC-113a present in the HFC-245fa feed with HF generated by the dehydrofluorination reaction of HFC-245fa. Since these CFCs are impurities and ozone-depleting substances, it is desirable to control the content of CFCs in the HFO-1234ze(E) product. In some jurisdictions, regulations limit the levels of these impurities for certain emission applications.

[0016] Accordingly, there is a need for a method for removing CFC-113 from the HFC-245fa feed and for removing CFC-114 from the HFO-1234ze(E) final product. The present disclosure is intended to address the removal of CFC-113 and CFC-114 at several locations or unit operations during the HFO-1234ze(E) manufacturing process.

[0017] HFO1234ze(E) can be industrially produced by a dehydrofluorination reaction shown in Equation 1 below.

[0018]

Chemical formula

[0019] The production of HFO-1234ze(E) involves the catalytic conversion of HFC-245fa by dehydrofluorinating HFC-245fa to produce a mixture containing a combination of cis and trans isomers of HFO-1234ze and hydrogen fluoride. Preferably, the dehydrofluorination of HFC-245fa may be carried out in the gas phase, for example, in a fixed bed reactor. The dehydrofluorination reaction may be carried out in any suitable reaction vessel or reactor, but preferably should be constructed from a material resistant to the corrosive action of hydrogen fluoride, such as nickel and its alloys including Hastelloy, Inconel, Incoloy, and Monel, or a container lined with a fluoropolymer.

[0020] The conversion of HFC-245fa to HFO-1234ze(E) and HFO-1234ze(Z) is limited by equilibrium. Thus, the reactor product stream often passes through several separation steps in order to recover HFO-1234ze(E) as the product and recycle the unconverted HFC-245fa back to the reactor.

[0021] If the feed HFC-245fa stream contains impurities such as CFC-113, the impurities can accumulate in the recycle stream and may interfere with the conversion and yield of the dehydrofluorination reaction. For example, if the recycle stream contains CFC-113, some of the CFC-113 entering the reactor can react with HF generated by the HFC-245fa dehydrofluorination reaction and convert CFC-113 to CFC-114 by the reaction shown in Equation 2 below.

[0022]

Chemical formula

[0023] The formation of CFC-114 in the reactor is a significant drawback as it is an undesirable impurity and is particularly difficult to separate from HFO-1234ze(E) at low CFC-114 concentrations.

[0024] Another alternative for reducing the accumulation of CFC-113 and CFC-114 would involve distilling the feed HFC-245fa stream to remove CFC-113. However, the separation of CFC-113 from HFC-245fa is difficult, especially at low concentrations of CFC-113, where a CFC-113 / HFO-245fa azeotrope may exist, and as will be further discussed below, such azeotropes have been found to be common, especially at low pressures.

[0025] III. Process for Producing HFO-1234ze(E) A general process for generating 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.

[0026] In the first method, discussed in more detail in Section IV, CFC-113 can be purged from the intermediate stream in a process where separation is easier so that smaller, less expensive equipment can be used with lower energy consumption and lower yield loss. By subjecting this intermediate stream to separation and distillation, a recycle stream containing unreacted HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), and a reduced amount of CFC-113 that can be fed back to the reactor, as well as a waste stream containing impurities that can be removed from the system, are obtained.

[0027] In the second method, discussed in more detail in Section V, the reaction mixture is exposed to an increased pressure during a separation stage that avoids the formation of a homogeneous minimum-boiling azeotrope at about 3.5 wt% CFC-113 and about 96.5 wt% HFC-245fa, as well as at a temperature of about 14.44 °C ± 0.3 °C and a pressure of about 14.29 psia ± 0.3 psia. This azeotrope is difficult to separate and is discussed in more detail in Sections VI and Example 1. Avoiding the formation of an azeotrope or an azeotrope-like mixture of CFC-113 and HFC-245fa can reduce the yield loss by reducing the excessive purge of HFC-245fa.

[0028] Optionally, to further reduce the level of CFC impurities, either system can be combined with several auxiliary separation devices 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.

[0029] An example of a general HFO-1234ze(E) process is shown in Figure 1 and summarized below. As shown therein, crude HFC-245fa enters the process via feed stream 10. Stream 10 optionally passes through a separation device 12, which initially reduces the level of CFC-113 in the HFC-245fa feed via one of several unit operations described below.

[0030] The composition in feed stream 10 can include HFC-245fa raw material and CFC-113 present as an impurity. Feed stream 10 can contain CFC-113 in an amount greater than 0 ppm, for example, in an amount of 1 ppm or more, or in an amount within any range that includes as endpoints any two of the values 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 less.

[0031] The separation device 12 may be any separation device suitable for reducing the level of CFC-113 in HFC-245fa. In one embodiment, the separation device may include a zeolite that utilizes differences in intermolecular structure or size. Suitable zeolites include sodium aluminosilicate, zeolite type X, AW-500, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, activated carbon, or carbon molecular sieve. In one embodiment, the separation device may include a zeolite that utilizes differences in intermolecular dipole moment. In one embodiment, the separation device may include an extractant to utilize differences in 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 separation device may include an azeotropic distillation apparatus. In one embodiment, the separation device may include a device that passes the mixture in the gas phase through mineral oil at a rate low enough to achieve dissolution of the undesired CFC impurities in the mineral oil, and a knockout pot that removes the oil from the desired components.

[0032] Stream 13 contains CFC-113, which can be removed from the system for disposal.

[0033] Stream 14, also referred to herein as the first product stream, transfers purified HFC-245fa to reactor 16, where the HFC-245fa is catalytically dehydrohalogenated to produce a product containing HFO-1234ze(E) as described above.

[0034] The composition in stream 14 can contain CFC-113 in an amount greater than 0 ppm, such as 1 ppm or more, or 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 an amount of 0 ppm, or an amount within any range bounded by any two of these values.

[0035] Reactor 16 can be operated at a low temperature such as 300°F, 325°F, 350°F, 375°F, 400°F, 425°F, 450°F, 475°F, 500°F, 525°F, 550°F, or a high temperature such as 575°F, 600°F, 625°F, 650°F, 675°F, 700°F, 725°F, 750°F, 775°F, 800°F, or at a temperature within any range bounded by any two of these values. Reactor 16 can also be operated at a low pressure such as 0 psia, 5 psia, 10 psia, 15 psia, 20 psia, 25 psia, 30 psia, 35 psia, 40 psia, 45 psia, 50 psia, or a high pressure such as 55 psia, 60 psia, 65 psia, 70 psia, 75 psia, 80 psia, 85 psia, 90 psia, 95 psia, 100 psia, or at a pressure within any range bounded by any two of these values. The residence time in reactor 16 can be as short as 0 seconds, 5 seconds, 10 seconds, 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, or as long as 55 seconds, 60 seconds, 65 seconds, 70 seconds, 75 seconds, 80 seconds, 85 seconds, 90 seconds, 95 seconds, 100 seconds, or within any range bounded by any two of these values.

[0036] Examples of the dehydrofluorination catalyst may include chromium oxide, chromium oxyfluoride, and chromium halide. Chromium oxide may include amorphous chromium oxide (Cr2O3), crystalline chromium oxide, and combinations thereof. Chromium oxyfluoride may include freshly prepared amorphous chromium oxide (Cr2O3) pretreated with HF, freshly prepared crystalline chromium oxide (Cr2O3) pretreated with HF, amorphous chromium oxyfluoride (CrO x F y (wherein x may be greater than 0 but may also be less than 1.5, and y may be greater than 0 but may also be less than 3)), crystalline chromium oxyfluoride (CrO x F y (wherein x may be greater than 0 but may also be less than 1.5, and y may be greater than 0 but may also be 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 may also be less than 1.5, and y may be greater than 0 but may also be less than 3)). Examples of chromium halide may include chromium trifluoride (CrF3), chromium trichloride (CrCl3), chromium triiodide (CrI3), chromium tribromide (CrBr3), and combinations thereof. In one embodiment, the catalyst is chromium trifluoride (CrF3).

[0037] Other suitable catalysts include chromium-based promoted catalysts or chromium-based doped catalysts, also referred to as chromium-based modified catalysts, which are based on chromium and contain a certain amount of at least one cocatalyst or modifier selected from K, Na, Cu, Ni, Zn, Co, Mn, Mg, or mixtures thereof. The amount of the cocatalyst or modifier may be from 0.1 wt% to 20 wt% based on the total weight of the catalyst, more specifically, based on the total weight of the catalyst, an amount as little as 0.1 wt%, 0.5 wt%, 1.0 wt%, 1.5 wt% or an amount as much as 2.0 wt%, 3.0 wt%, 4.0 wt%, 5.0 wt%, 6.0 wt% or an amount within any range inclusive of any two of these values as endpoints. One suitable chromium-promoted catalyst is a zinc / chromia catalyst based on chromia and containing a certain amount of zinc as a cocatalyst, 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 some of the metal oxides to the corresponding metal fluorides.

[0038] The above chromium-based catalyst may also be a low chromium(VI) catalyst with a total chromium(VI) oxide content of about 5000 ppm or less, about 2000 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.

[0039] In addition to chromium-based catalysts, other suitable catalysts include alumina, iron oxide, magnesium oxide, zinc oxide, nickel oxide, cobalt oxide, aluminum fluoride or metal fluorides such as iron fluoride, magnesium fluoride, zinc fluoride, nickel fluoride, cobalt fluoride, fluorinated alumina, fluorinated iron oxide, fluorinated magnesium oxide, fluorinated nickel oxide, fluorinated cobalt oxide, titanium fluoride, molybdenum fluoride, aluminum oxyfluoride, and combinations thereof. Prior to use, the metal oxide(s) containing catalyst is fluorinated using anhydrous HF under conditions effective to convert some of the metal oxides to the corresponding metal fluorides. Halides of pentavalent antimony, niobium, arsenic and tantalum are commercially available and their mixed halides are prepared in situ during reaction with HF. Antimony pentachloride is preferred due to its low cost and availability. Wherein n is from 0 to 5, the formula SbCl n F 5-n of the pentavalent antimony mixed halide is more preferred. The fluorinated catalyst preferably has a purity of at least about 97%. The amount of fluorinated catalyst used can vary widely, but it is appropriate to use about 5 to about 50 wt%, or preferably about 10 to about 25 wt% of the catalyst based on the organic matter.

[0040] Following the dehydrofluorination reaction, the crude product stream 18 is transferred to a separation device 20 for HF removal.

[0041] The composition in stream 18 includes the crude product of the reactor which may contain 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 little 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 much as 16 wt%, 17 wt%, 18 wt%, 19 wt%, 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt% based on the total weight of the composition of the stream, or in any range encompassing any two of these values as endpoints.

[0042] The separation device 20 may be any separation device suitable for reducing the level of HF in the composition of stream 18. In one embodiment, HF can be recovered using water or a caustic scrubber, or by contacting it 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 the sulfuric acid, and then distilling the desorbed hydrogen fluoride. The separation may be carried out by adding sulfuric acid to the mixture while the mixture is in either the liquid or gaseous state. In an alternative embodiment, the recovery of HF from the mixture may be carried out by a continuous process of introducing a stream of sulfuric acid into stream 18 in the gas phase. This may be done by flowing the sulfuric acid stream countercurrently to stream 18 in a standard scrubber column. In another embodiment, HF may be removed by adsorption onto carbon molecular sieves, HF-polymer gels, membranes, or zeolites.

[0043] After removal of HF, stream 22 is condensed in condenser 24 to produce stream 26.

[0044] The composition in stream 22 may include the crude product of the reactor containing 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 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%.

[0045] The condenser 24 can be operated at a pressure as low as about 0 psia, 10 psia, 20 psia, 30 psia, 40 psia, 50 psia, 60 psia, 70 psia, or as high as about 80 psia, 90 psia, 100 psia, 110 psia, 120 psia, 130 psia, 140 psia, 150 psia, or at a pressure within any range that encompasses any two of these values as endpoints. The condenser 24 can be operated at a temperature as low as about -20 °C, -10 °C, 0 °C, 10 °C, or as high as about 20 °C, 40 °C, 50 °C, 60 °C, or at a temperature within any range that encompasses any two of these values as endpoints.

[0046] The stream 26 is supplied to a separation device 28, which separates the reaction mixture into a stream 30 and a waste stream 52 containing light impurities.

[0047] As used herein, the term "light impurities" refers to impurities or azeotropes having a boiling point below -19 °C, i.e., below the boiling point of HFO-1234ze(E). Examples of light impurities include, but are not limited to, 3,3,3-trifluoropropyne (TFPy), the TFPy / water azeotrope, the TFPy / HF azeotrope, the HFO-1234ze(E) / water azeotrope, the 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).

[0048] The composition in stream 26 may contain 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 little as 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt% based on the total weight of the composition of the stream, or as much as 0.06 wt%, 0.07 wt%, 0.08 wt%, 0.09 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, or may be within any range encompassing any two of these values as endpoints.

[0049] Separation device 28 may 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 fractional distillation columns, spinning band distillation equipment, or wiped film evaporators. Waste stream 29 contains light impurities, which can be removed from the reaction mixture.

[0050] Stream 30 is fed to separation device 32 to obtain a crude product stream 44 containing HFO-1234ze(E) and stream 34.

[0051] Stream 30 may contain CFC-113, HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), CFC-114, a reduced amount of light impurities, heavy impurities, and a reduced amount of 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%.

[0052] 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, batch or continuous fractional distillation columns, spinning band distillation equipment, or wiped film evaporators.

[0053] In this specification, the stream 44, also referred to as the second product stream, is optionally supplied to a separation device 46, which reduces the level of CFC-114 and results in a purified final product HFO-1234ze(E) in stream 48. Stream 47 contains CFC-114, which can be removed from the system for disposal.

[0054] Stream 44 can contain CFC-114 and HFO-1234ze(E). The amount of CFC-114 can 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.

[0055] Stream 48 is a purified product stream that can contain HFO-1234ze(E) and CFC-114 in an amount less than 0.001 wt%, less than 0.0005 wt%, or less than 0.00001 wt%.

[0056] The separation device 46 may be any separation device suitable for reducing the amount of CFC-114 in HFO-1234ze(E). In one embodiment, the separation device may include a zeolite that utilizes the difference in structure or size between molecules. Suitable zeolites include sodium aluminosilicate, zeolite type X, AW-500, 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, activated carbon, or activated carbon molecular sieve. In one embodiment, the separation device may include a zeolite that utilizes the difference in dipole moment between molecules. In one embodiment, the separation device may include an extractant to utilize the different solubilities between molecules. Suitable extractants include, but are not limited to, pentane, hexane, ethyl acetate, dichloromethane, chloroform, tetrahydrofuran, methanol, or water. In one embodiment, the separation device may include an azeotropic distillation apparatus. In one embodiment, the separation device may include a device that passes the mixture in the gas phase through mineral oil at a rate low enough to achieve dissolution of the undesired CFC impurities in the mineral oil, and a knockout pot that excludes the oil from the desired components.

[0057] As used herein, stream 34, also referred to as the third product stream, is fed to distillation apparatus 36, which results in a bottoms stream containing heavy impurities in stream 42 for removal and an overhead recycle stream 50 that is fed back to the feed stream.

[0058] As used herein, the term "heavy impurities" refers to impurities or azeotropes having a boiling point higher than -19°C, i.e., higher than the boiling point of HFO-1234ze(E). Examples of heavy impurities include, but are not limited to, HCFO-1233ze(E) (trans-1-chloro-3,3,3-trifluoro-propene), HCFO_1233zd(Z) (cis-1-chloro-3,3,3-trifluoro-propene), HCFC-244fa (3-chloro-1,1,1,3-tetrafluoropropane), and CFC-113.

[0059] Stream 34 may contain CFC-113, HFC-245fa, and HFO-1234ze(Z), and less than 0.001 wt% of HFO-1234ze(E).

[0060] Distillation unit 36 can be used to separate and purge heavy impurities from the system. The use of unit 36 can be carried out in a continuous or batch process. Unit 36 can be operated at a low pressure such as 0 psia, 10 psia, 20 psia, 30 psia, 40 psia, 50 psia, 60 psia, 70 psia, or a high pressure such as 80 psia, 90 psia, 100 psia, 110 psia, 120 psia, 130 psia, 140 psia, 150 psia, or at a pressure within any range that includes any two of these values as endpoints. Unit 36 can be operated at a low temperature such as 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, or a high temperature such as 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, or at a temperature within any range that includes any two of these values as endpoints.

[0061] Waste stream 42 contains heavy impurities such as CFC-113 that can be removed from the system as waste, where the amount of CFC-113 in stream 42 can be 1 wt% or more, 2.5 wt% or more, 4 wt% or more, 6 wt% or less, 7.5 wt% or less, or 10 wt% or less, or within any range that includes any two of these values as endpoints.

[0062] Recycle stream 50 may contain CFC-113, HFC-245fa, an azeotrope of CFC-113 and HFC245fa, HFO-1234ze(Z), and HFO-1234ze(E).

[0063] The heating system for the reactor and distillation can include any suitable heating medium capable of achieving and / or maintaining the temperature required for the process. Suitable heating media can include, for example, among others, molten salt, thermal oil, steam, and electric heaters (resistive or inductive).

[0064] IV. Purge of CFC-113 from the Recycle Stream As shown in Example 2A below, it has been found that it is not necessary to focus only 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 the intermediate stream in a process where separation is easier so that smaller, less expensive equipment can be used with lower energy consumption and lower yield loss. By subjecting this intermediate stream to separation and distillation, a recycle stream containing unreacted HFC-245fa, HFO-1234ze(Z), HFO-1234ze(E), and a reduced amount of CFC-113 that can be fed back to the reactor, as well as a waste stream containing impurities that can be removed from the system, are obtained.

[0065] As further discussed in Section VI below, CFC-113 and HFC-245fa have been found to form a homogeneous minimum-boiling azeotropic mixture at about 3.5 wt% CFC-113 and about 96.5 wt% 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.

[0066] This process follows the same flow as outlined in Section III and Figure 1, but the level of CFC-113 accumulates in the recycle stream before being purged from the system. Due to the discovered azeotropic behavior of the CFC-113 and HFC-245fa mixture, it can be beneficial to remove CFC-113 from the recycle stream when it 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 method balances reducing CFC impurities to an acceptable level while minimizing unnecessary separation and reducing yield loss. Allowing the concentration of CFC-113 to accumulate before it is removed avoids attempts to separate components at the pinch point in the CFC-113 and HFC-245fa mixture.

[0067] V. Performing Separation at Higher Pressures Also, as shown in Examples 2B and 5 below, the vapor-liquid equilibrium regarding the formation of an azeotrope or an azeotrope-like mixture of CFC-113 and HFC-245fa is pressure-dependent, and the azeotropic behavior between CFC-113 and HFC-245fa can be substantially or completely avoided when a mixture containing CFC-113 and HFC-245fa is exposed to pressures higher than about 17 psia, for example, by operating the separation stage of the present process at such elevated pressures to avoid the formation of an azeotrope.

[0068] Operating the separation step of CFC-113 from HFC-245fa at these higher pressures advantageously avoids any need to remove CFC-113 after concentrating it in the recycle stream according to the method discussed in Section IV above. Further, operating at higher pressures avoids the formation of the CFC-113 / HFC-245fa azeotrope, and as a result, these components can be effectively separated according to the difference in their boiling points, making the final separation of CFC-113 from HFC-245fa easier.

[0069] This process follows the same flow as outlined in Section III and FIG. 1, but the pressure within the distillation apparatus is higher, the amount of CFC-113 in the waste stream is increased, and the amount of CFC-113 in the recycle stream is decreased. All other parameters, including the reactor setup and temperature conditions, are the same as those described above in Section III.

[0070] The distillation apparatus 36 can be operated 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 within any range including any two of these values as endpoints.

[0071] The waste stream 42 contains heavy impurities such as CFC-113 that can be removed from the system as waste, where 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 within any range including any two of these values as endpoints.

[0072] The recycle stream 50 can contain 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 can 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 within any range including any two of these values as endpoints.

[0073] VI. Azeotropic Composition Containing HFC-245fa and CFC-113 The inventors have experimentally found that HFC-245fa and CFC-113 form an azeotropic or azeotrope-like composition at pressures below 25 psia. The discovery of this azeotropic mixture is relevant to the process for converting HFC-245fa to HFO-1234ze(E). CFC-113 is an undesirable impurity that may be found in HFC-245fa feedstocks and may convert to CFC-114 during the dehydrofluorination reaction to produce HFO-1234ze(E). Therefore, a method for separating the mixture of HFC-245fa and CFC-113 is necessary to prevent the accumulation of CFCs throughout the HFO-1234ze(E) process.

[0074] An "azeotropic" composition is a specific combination of two or more components. Azeotropic compositions can be characterized in various ways. For example, at a given pressure, an azeotropic composition boils at a constant characteristic temperature that is higher than the component with the higher boiling point (maximum-boiling azeotrope) or lower than the component with the lower boiling point (minimum-boiling azeotrope). At this characteristic temperature, the same composition exists in both the gas phase and the liquid phase. Azeotropic compositions do not fractionate upon boiling or evaporation. Therefore, the components of an azeotropic composition cannot be separated by a phase change.

[0075] An azeotropic composition is also characterized in that at the characteristic azeotropic temperature, the bubble point pressure of the liquid phase is the same as the dew point pressure of the gas phase.

[0076] The behavior of an azeotropic composition is in contrast to that of a non-azeotropic composition in which the liquid composition changes significantly during boiling or evaporation.

[0077] For the purposes of the present disclosure, an azeotropic composition is characterized as a composition that boils at a constant characteristic temperature lower than the boiling points of two or more components (minimum-boiling azeotrope), thereby having the same composition in both the gas phase and the liquid phase.

[0078] However, those skilled in the art would understand that at different pressures, both the composition and the boiling point of the azeotropic composition change to some extent. Therefore, depending on the temperature and / or pressure, the azeotropic composition can have a variable composition. Thus, those skilled in the art would understand that the azeotropic composition can be defined using a composition range rather than a fixed composition. Further, an azeotrope can also be defined from the perspective of the exact weight percentage of each component of the composition characterized by a fixed boiling point at a specific pressure.

[0079] An "azeotrope-like" composition is a composition of two or more components that behaves substantially as an azeotropic composition. Thus, for the purposes of the present disclosure, an azeotrope-like composition is a combination of two or more different components that boils at a substantially constant temperature when in liquid form under a given pressure and provides a gas composition that is substantially the same as the liquid composition during boiling.

[0080] For the purposes of the present disclosure, an azeotropic or azeotrope-like composition comprising HFC-245fa and CFC-113 is a composition or range of compositions that boils in a temperature range of about 14.44°C ± 0.3°C at a pressure of about 14.29 psia ± 0.3 psia.

[0081] Azeotropic or azeotrope-like compositions can be identified using a number of different methods. For the purposes of the present disclosure, azeotropic or azeotrope-like compositions are identified experimentally using an ebulliometer (Walas, Phase Equilibria in Chemical Engineering, Butterworth-Heinemann, 1985, 533 - 544). An ebulliometer is designed to provide a very accurate measurement of the boiling point of a liquid by measuring the vapor-liquid equilibrium temperature.

[0082] The individual boiling points of the components are measured at a constant pressure. As understood by those skilled in the art, for a binary azeotropic or azeotrope-like composition, the boiling point of one of the components of the composition is measured first. Then, the second component of the composition is added in various amounts, and the boiling point of each of the resulting compositions is measured using an ebulliometer at the said constant pressure.

[0083] The measured boiling points are plotted against the composition of the tested composition, for example, in the case of a binary azeotrope, against the amount of the second component added to the composition (expressed in either weight % or mole %). The presence of an azeotropic composition can be identified by observing a maximum or minimum boiling temperature that is higher or lower than the boiling point of either of the individual components.

[0084] As understood by those skilled in the art, the identification of an azeotropic or azeotrope-like composition is done by comparing the change in the boiling point of the composition when the second component is added to the first component with the boiling point of the first component. Thus, there is no need to calibrate the system to the reported boiling point of a particular component in order to measure the change in boiling point.

[0085] As described above, at the maximum or minimum boiling point, the composition of the gas phase is the same as that of the liquid phase. Thus, an azeotrope-like composition is a composition of components that provides a substantially constant minimum or maximum boiling point that is 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 gas phase will be substantially the same as that of the liquid phase.

[0086] An azeotropic 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% of CFC-113, about 1 wt% to about 10 wt% of CFC-113, about 1 wt% to about 5 wt% of CFC-113, or about 3.5 wt% of CFC-113, and about 85 wt% to about 99 wt% of HFC-245fa, about 90 wt% to about 99 wt% of HFC-245fa, about 95 wt% to about 99 wt% of HFC-245fa, or about 96.5 wt% of HFC-245fa.

[0087] In other words, an azeotropic 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% of CFC-113 and about 85 wt% to about 99 wt% of HFC-245fa, or about 1 wt% to about 10 wt% of CFC-113 and about 90 wt% to about 99 wt% of HFC-245fa, or about 1 wt% to about 5 wt% of CFC-113 and about 95 wt% to about 99 wt% of HFC-245fa, or about 3.5 wt% of CFC-113 and about 96.5 wt% of HFC-245fa.

[0088] Stated another way, an azeotropic or azeotrope-like composition at a pressure of about 14.29 psia ± 0.3 psia and a boiling point of about 14.44 °C ± 0.3 °C includes, consists essentially of, or consists of at least about 1 wt% less of CFC-113, or up to about 5 wt%, about 10 wt%, or about 15 wt% more of CFC-113, or any range defined between any two of these values, and the azeotropic or azeotrope-like composition includes, consists essentially of, or consists of at least about 85 wt%, about 90 wt%, about 95 wt% less of HFC-245fa, or up to about 99 wt% more of HFC-245fa, or any range defined between any two of these values.

[0089] The azeotropic 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.

[0090] The azeotropic or azeotrope-like composition has also been found to be pressure-dependent. Certain minimum or maximum boiling point behaviors are observed at pressures below about 17 psia, and above about 17 psia, no azeotropic or azeotrope-like behavior is observed.

[0091] For example, the azeotropic or azeotrope-like composition may be present at pressures within any range encompassed by a pressure below 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 any range between any two of these values as endpoints.

[0092] The azeotropic or azeotrope-like composition may not be present at pressures above 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 any range between any two of these values as endpoints.

[0093] As used herein, the phrase "within any range encompassed by any two of these values as endpoints" literally means that, regardless of whether the values are at the lower or higher part of the enumeration, any range can be selected from any two of the values listed before the phrase to which the range applies. For example, a pair of values can be selected from two lower values, two higher values, or a lower value and a higher value.

Examples

[0094] Example 1 - Investigation with an ebulliometer An ebulliometer was used to measure the azeotropy and azeotrope-like compositions of HFC-245fa and CFC-113. The ebulliometer included a glass vessel with a vacuum jacket sealed at the bottom and open to air at the top. The upper part or the condenser jacket of the ebulliometer was filled with a mixture of dry ice and ethanol to achieve a temperature of about -72 °C, which is significantly lower than the normal boiling points of 1,1,1,3,3-pentafluoropropane (HFC-245fa) at 15.3 °C and 1,1,2-trichloro-trifluoroethane (CFC-113) at 47.5 °C at a pressure of 14.40 psia. In this way, all the vapors in the system were condensed and refluxed to the ebulliometer, ensuring that the liquid and vapor phases were in equilibrium. A quartz-platinum thermometer with an accuracy of ±0.002 °C was inserted into the glass vessel and used to determine the temperature of the condensed vapor corresponding to the equilibrium boiling point of the mixture. Boiling stones were used to assist in maintaining smooth boiling of the mixture in the ebulliometer.

[0095] The following procedure was used. 1. The quartz thermometer was immersed in a long Dewar containing an ice / water slurry, and it was confirmed that the thermometer read 0 °C. The Dewar was deep enough so that at least 3 / 4 of the length of the thermometer shaft was immersed in the ice / water. The resistance of the thermometer was recorded in ohms. 2. The condenser jacket was filled 1 / 4 full with ethanol. The condenser jacket was cooled by slowly introducing dry ice, avoiding the ethanol from boiling over and / or splashing. 3. A known amount of CFC-113 or HFC-245fa was added to the ebulliometer and brought to a vigorous reflux state. A barometer with a temperature indicator was used to record the temperature and the atmospheric pressure.

[0096] The measurement was carried out in two steps. In the first step, first, about 24.50 g of CFC-113 with a purity of 99.88 area% determined by gas chromatography (GC) was introduced into an ebulliometer by weighing the container before and after addition using a scale with an accuracy of ±0.01 g. The liquid was boiled, and the equilibrium temperature of CFC-113 was recorded at the recorded atmospheric pressure. Then, HFC-245fa with a purity of 99.99 area% determined by gas chromatography (GC) was introduced into the ebulliometer while increasing it slightly, and the equilibrium temperature of the condensed liquid mixture was recorded.

[0097] In the second step, about 16.09 g of HFC-245fa with a purity of 99 area% determined by gas chromatography (GC) was introduced into an ebulliometer by weighing the container before and after addition using a scale with an accuracy of ±0.01 g. The liquid was boiled, and the equilibrium temperature of HFC-245fa was recorded at the recorded atmospheric pressure. Then, CFC-113 with a purity of 99.88 area% determined by gas chromatography (GC) was introduced into the ebulliometer while increasing it slightly, and the equilibrium temperature of the condensed liquid mixture was recorded.

[0098] Combining the data from the above first and second steps, the data for each composition range of HFC-245fa and CFC-113 from 0 to 100 weight percent presented in Table 2 below was completed. This indicates a minimum in temperature indicating the formation of an azeotrope, and this data is also presented in graphical form in Figure 2. The data suggests the formation of a weak minimum-boiling azeotrope at about 3.5 weight% of CFC-113 at a pressure of 14.29 Psia. The azeotropic temperature is 14.44 °C, which is below the boiling point of HFC-245fa.

[0099]

Table 2

[0100] Process for Removing CFC-114 from HFO-1234ze(E) by Purging CFC-113 from the Recirculation Stream in Example 2A Example 2A provides the material balance for each stream in the process depicted in FIG. 1.

[0101] [Table 3]

[0102] As shown in FIG. 1, CFC-113 impurities are removed from the recirculation stream of the process of HFC-245fa to HFO-1234ze(E) via distillation at a pressure below 17 psia. The recirculation stream 50 mainly contains unreacted HFC-245fa, HFO-1234ze(Z), 1234ze(E), and CFC-113. Due to the difficulty in separating CFC-113 from HFC-245fa, it is beneficial to remove 113 from the recirculation stream where the component accumulates to 1 wt% or more. Since CFC-113 is a high-boiling impurity, it can be removed in the heavy impurity purge stream 42.

[0103] Process for Removing CFC-114 from HFO-1234ze(E) by Operating at a Higher Pressure in Example 2B Example 2B provides the material balance for each stream in the process depicted in FIG. 1. Example 2B differs from 2A in that the removal of CFC-113 via distillation (block 36) is carried out at a pressure above 17 psia and there is no need to accumulate 113 in the recirculation stream 50.

[0104] [Table 4]

[0105] As shown in Figure 1, CFC-113 impurities are removed from the recycle stream of the process of HFC-245fa to HFO-1234ze(E) via distillation at pressures above 17 psia. Recycle stream 50 mainly contains unreacted HFC-245fa, HFO-1234ze(Z), 1234ze(E), and CFC-113. Since there is no azeotrope between 113 and 245fa at this pressure, it is not necessary to have 113 up to 1 wt% or more. This reduces the amount of 113 supplied to the reactor (block 16) and the amount of 114 generated by the reactor. Since CFC-113 is a high-boiling impurity, it can be removed in the heavy impurity purge stream 42.

[0106] Example 3 - Separation of the CFC-113 / HFC-245fa Mixture Example 3A - Adsorbent Referring back to Figure 1, CFC-113 is removed from the stream containing CFC-113 and HFC-245fa by passing it through an adsorption device containing molecular sieves. Thereby, the amount of CFC-113 is reduced to an acceptable level for the HFC-245fa feed stream.

[0107] Example 3B - Liquid Extraction Referring back to Figure 1, CFC-113 is removed from the stream containing CFC-113 and HFC-245fa by liquid extraction using a mixture of hexane and ethyl acetate. Thereby, the amount of CFC-113 is reduced to an acceptable level for the HFC-245fa feed stream.

[0108] Example 3C - Mineral Oil Extraction Referring back to FIG. 1, CFC-113 is removed from the stream containing CFC-113 and HFC-245fa by mineral oil extraction. A stream of HFC-245fa containing 0.50 wt% CFC-113 is vaporized and fed to the bottom of a packed column at a feed rate of about 2.2 lbs per hour for about 4 hours. The stream of mineral oil is continuously fed to the top of the same packed column at a feed rate of about 3.5 lbs per hour during the same time frame. The gas stream exiting from the top of the column contains HFC-245fa having less than 0.10 wt% CFC-113. The concentration of CFC-113 in the mineral oil increases from undetectable to about 0.25 wt%.

[0109] Example 4 - Separation of a Mixture of CFC-114 / HFO-1234ze(E) Example 4A - Adsorbent Referring back to FIG. 1, CFC-114 is removed from the stream containing CFC-114 and HFO-1234ze(E) by passing it through an adsorption device containing molecular sieves. Thereby, the amount of CFC-114 is reduced to an acceptable level for the HFO-1234ze(E) product stream.

[0110] Example 4B - Liquid Extraction Referring back to FIG. 1, CFC-114 is removed from the stream containing CFC-114 and HFO-1234ze(E) by liquid extraction using a mixture of hexane and ethyl acetate. Thereby, the amount of CFC-114 is reduced to an acceptable level for the HFO-1234ze(E) product stream.

[0111] Example 4C - Mineral Oil Extraction Referring back to FIG. 1, CFC-114 is removed from the stream containing CFC-114 and HFO-1234ze(E) by mineral oil extraction. The stream of HFO-1234ze(E) containing 0.20 wt% CFC-114 impurities is vaporized and fed to the bottom of the packed column at a feed rate of about 2.1 lbs per hour for about 4 hours. The stream of mineral oil is continuously fed to the top of the same packed column at a feed rate of about 3.3 lbs per hour during the same time frame. The gas stream exiting the top of the column contains HFO-1234ze(E) with less than 0.050 wt% CFC-114. The concentration of CFC-114 in the mineral oil increases from undetectable to about 0.095 wt%.

[0112] Example 5 - Investigation of HFC-245fa and CFC-113 Mixtures in an Ebulliometer at Different Pressures HFC-245fa and CFC-113 were tested in an isobaric ebulliometer. The pressure was set using a pressure controller and the temperature was measured using an RTD. Filling and addition were done volumetrically through a pump. The following data sets are the results from these experiments. The conclusion was that the azeotropic composition shifts based on pressure and is predicted to break above 20.4 psia.

[0113]

Table 5

[0114] These data are plotted in FIGS. 3 - 5. FIG. 3 shows a minimum-boiling azeotrope at 92.20 wt% HFC-245fa at a pressure of 5 psia. FIG. 4 shows a minimum-boiling azeotrope at 95.01 wt% HFC-245fa at a pressure of 10 psia. FIG. 5 shows a minimum-boiling azeotrope at 97.01 wt% HFC-245fa at a pressure of 14.7 psia.

[0115] As the pressure increases through Figures 3 to 5, the azeotropic behavior becomes weaker, indicating that the azeotropic behavior between HFC-245fa and CFC-113 is pressure-dependent. Figure 6 plots the pressure against the azeotropic composition (mass %) of HFC-245fa, showing that the locus of the azeotrope shifts with pressure.

[0116] Aspect Aspect 1 is a process for producing HFO-1234ze(E), which comprises reacting a feed stream containing HFC-245fa and CFC-113 in a reactor in the presence of a catalyst to form a first product stream containing HFO-1234ze(E), unreacted HFC-245fa, and CFC-113; separating the first product stream into a second product stream containing HFO-1234ze(E) and a third product stream containing unreacted HFC-245fa and CFC-113; distilling the third product stream to produce a top recycle stream and a bottom stream, wherein the recycle stream contains unreacted HFC-245fa and a first amount of CFC-113, and the bottom stream contains a second amount of CFC-113 that is greater than the first amount; and transferring the recycle stream back to the feed stream.

[0117] Aspect 2 is the process of Aspect 1, wherein the distillation is carried out at a pressure above 17 psia.

[0118] Aspect 3 is the process of Aspect 1 or 2, wherein the recycle stream contains less than 3 wt% of CFC-113.

[0119] Aspect 4 is the process of any one of Aspects 1 to 3, wherein the distillation step comprises distilling the third product stream when the amount of CFC-113 is 1 wt% or more based on the total weight of the third product stream.

[0120] Aspect 5 is the process of 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.

[0121] Aspect 6 is a process according to any of Aspects 1 to 5, wherein the first product stream additionally contains hydrogen fluoride (HF), and is transferred to a separation device before entering a distillation apparatus for removing CFC-113, and the HF is removed.

[0122] Aspect 7 is a process according to Aspect 6, wherein the separation device includes at least one of water or a caustic scrubber, a metal salt, a sulfuric acid extractor, a vapor-phase sulfuric acid extractor, a distillation column, and combinations thereof.

[0123] Aspect 8 is a process according to any of Aspects 1 to 7, wherein the first product stream additionally contains at least one light impurity including 3,3,3-trifluoropropyne (TFPy), a TFPy / water azeotrope, a TFPy / HF azeotrope, an HFO-1234ze(E) / water azeotrope, an 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), or HFO-1234zf (2,3,3,3-tetrafluoropropene), and combinations thereof, and is transferred to a separation device before entering a distillation apparatus for removing CFC-113, and the light impurity is removed.

[0124] Aspect 9 is a process according to Aspect 8, wherein the separation device includes at least one of a batch or continuous fractional distillation column, spinning band distillation equipment, a wiped film evaporator, and combinations thereof.

[0125] Aspect 10 is a process according to Aspect 8, wherein the level of the light impurity is reduced to 1 wt% or less based on the total weight of the intermediate stream.

[0126] Aspect 11 is a process of any one of Aspects 1 - 10, wherein the reactor is operated at at least one of the following conditions: (i) a temperature of about 205°C to 370°C, (ii) a pressure of about - 15 to 100 psia, and (iii) a residence time of about 1 second to 100 seconds.

[0127] Aspect 12 is a process of Aspect 1, wherein the distillation apparatus is operated at at least one of the following conditions: (i) a temperature of about 10°C to 105°C, and (ii) a pressure of about - 15 to 150 psia.

[0128] Aspect 13 is a process for removing CFC - 113 from an HFC - 245fa feed stream in the production of HFO - 1234ze(E), the process comprising: supplying HFC - 245fa, which further contains a first amount of CFC - 113, to a separation device; and recovering from the separation device a purified HFC - 245fa stream having a second amount of CFC - 113 that is less than the first amount.

[0129] Aspect 14 is a process of Aspect 13, wherein the separation device comprises at least one of zeolite, a liquid extractant, an azeotropic distillation apparatus, mineral oil, and combinations thereof.

[0130] Aspect 15 is a process of Aspect 13, wherein the purified HFC - 245fa stream contains less than 0.05 wt% CFC - 113 based on the total weight of the purified HFC - 245fa stream.

[0131] Aspect 16 is a process for removing CFC-114 from an HFO-1234ze(E) production stream in an HFO-1234ze(E) process, the process comprising: supplying HFO-1234ze(E), which is HFO-1234ze(E) and further contains a first amount of CFC-114, to a separation device; and recovering from the separation device a purified HFO-1234ze(E) stream having a second amount of CFC-114 that is less than the first amount.

[0132] Aspect 17 is the process of aspect 16, wherein the separation device comprises at least one of zeolite, a liquid extractant, an azeotropic distillation apparatus, a mineral oil, and combinations thereof.

[0133] Aspect 18 is the process of aspect 16, wherein the purified HFO-1234ze(E) stream contains less than 0.01 wt% CFC-114.

[0134] Aspect 19 is a composition comprising an azeotropic or azeotrope-like composition consisting essentially of an effective amount of CFC-113 and HFC-245fa.

[0135] Aspect 20 is the composition of aspect 19, wherein the azeotropic or azeotrope-like composition consists essentially of about 3.5 wt% CFC-113 and about 96.5 wt% HFC-245fa.

[0136] It should be understood that the foregoing description is merely illustrative of the present disclosure. Various alternative forms and modifications can be devised by those skilled in the art without departing from the present disclosure. Accordingly, the present disclosure is intended to embrace all such alternative forms, modifications, and variations that fall within the scope of the appended claims.

Claims

Claim 1 A process for producing HFO-1234ze(E), 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 a top recycle stream and a bottom stream, wherein the recycle stream comprises unreacted HFC-245fa and a first amount of CFC-113, and the bottom stream comprises a second amount of CFC-113 greater than the first amount; transferring the recycle stream back to the feed stream. A process for producing HFO-1234ze(E). Claim 2 The process of claim 1, wherein the distillation is carried out at a pressure above 17 psia. Claim 3 The process of claim 1, wherein the recycle stream comprises less than 3 wt% CFC-113. Claim 4 The process of claim 1, wherein the distillation step comprises distilling the third product stream when the amount of CFC-113 is 1 wt% or more based on the total weight of the third product stream. Claim 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. Claim 6 The process of claim 1, wherein the first product stream additionally comprises hydrogen fluoride (HF) and is transferred to a separation device before entering a distillation apparatus for removing CFC-113, and the HF is removed. Claim 7 The process of claim 6, wherein the separation device comprises at least one of water or a caustic scrubber, a metal salt, a sulfuric acid extractor, a vapor phase sulfuric acid extractor, a distillation column, and combinations thereof. Claim 8 The first product stream additionally contains light impurities including at least one of 3,3,3-trifluoropropene (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), or HFO-1234zf (2,3,3,3-tetrafluoropropene), and combinations thereof, and is transferred to a separation device before entering a distillation apparatus for removing CFC-113, where the light impurities are removed. The process according to claim 1.

9. The process according to claim 8, wherein the separation device includes at least one of a batch or continuous fractional distillation column, spinning band distillation equipment, a wiped film evaporator, and combinations thereof.

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

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

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

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

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

15. The composition according to claim 14, wherein the azeotropic or azeotrope-like composition consists essentially of about 3.5% by weight of CFC-113 and about 96.5% by weight of HFC-245fa.

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