Process for catalytic conversion of mixtures of HCFO-1233zd(z) and HCFC-244fa into HCFO-1233zd(e)

Abstract

To provide a method for forming HCFO-1233zd(E).SOLUTION: A method for conversion of a composition containing HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E), comprises reacting a mixture including HCFO-1233zd(Z) and HCFC-244fa in a vapor phase in the presence of a catalyst to simultaneously isomerize HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenate HCFC-244fa to form HCFO-1233zd(E). The catalyst may be a chromium-based catalyst, such as chromium trifluoride, chromium oxyfluoride, or chromium oxide.SELECTED DRAWING: Figure 2

Description

[Background technology]

[0001] 1. Field of Disclosure The present disclosure relates to a process for the catalytic conversion of a mixture of (Z)-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(Z), or 1233zd(Z)) and 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa, or 244fa) to (E)-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(E), or 1233zd(E)).

[0002] 2. Description of Related Technology (E)-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(E), or 1233zd(E)) is a new low global warming and non-ozone depleting molecule with applications as a blowing agent, solvent, and refrigerant. The uses and interest in this molecule have led to the development of several manufacturing processes for its production. On a commercial scale, HCFO-1233zd(E) is produced by the fluorination of 1,1,1,3,3-pentachlorodipropane (HCC-240fa) with hydrofluoric acid (HF), where (Z)-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(Z), or 1233zd(Z)), along with about 2% to 10% by weight of 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa, or 244fa), is produced as a by-product in a ratio of HCFO-1233zd(E) to HCFO-1233zd(Z) of about 10 to 20:1. Unfortunately, the formation of HCFO-1233zd(Z) and HCFC-244fa results in reduced yields.

[0003] Due to the fact that the boiling points of HCFO-1233zd(Z) and HCFC-244fa are similar, corresponding mixtures of these compounds exhibit azeotrope-like properties, and the two components cannot be separated by conventional distillation techniques. Additionally, while HCFO-1233zd(Z) has been applied as an alternative higher-boiling solvent, HCFC-244fa is particularly toxic, making it impossible to store mixtures of these compounds for long periods of time. As a result, mixtures of HCFC-244fa and HCFO-1233zd(Z) obtained from commercial production of HCFO-1233zd(E) are typically shipped to thermal oxidation units for disposal, incurring additional production costs.

[0004] Therefore, there is an increasing need to develop applications for the production of mixtures of HCFC-244fa and HCFO-1233zd(Z) that reduce waste, improve overall yield, and lower production costs. Summary of the Invention

[0005] The present disclosure provides a process for converting a composition containing HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E) by reacting the mixture in the vapor phase in the presence of a catalyst to simultaneously isomerize HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenate HCFC-244fa to form HCFO-1233zd(E). The catalyst may be, for example, a chromium-based catalyst such as chromium trifluoride, chromium oxyfluoride, or chromium oxide.

[0006] In one form thereof, the invention is a method for co-converting a composition containing HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E). and reacting the composition in the vapor phase in a reactor in the presence of a chromium trifluoride (CrF3) catalyst to simultaneously isomerize HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenate HCFC-244fa to form HCFO-1233zd(E).

[0007] The reaction step may be carried out at a temperature of 80°C to 250°C, or 100°C to 200°C. The contact time between the composition and the catalyst may be 1 second to 150 seconds, or 25 seconds to 125 seconds. The pressure in the reactor may be 25 psig to 100 psig.

[0008] During the reaction step, the reactor may contain less than 50 ppm water. The reaction step may achieve 88% to 96% conversion of HCFO-1233zd(Z) to HCFO-1233zd(E), may achieve 90% to 99% conversion of HCFC-244fa to HCFO-1233zd(E), and / or may achieve 90% to 97% selectivity for HCFO-1233zd(E).

[0009] In the providing step, total impurities may be present in an amount of less than 10 wt.% based on the total weight of the composition, may be present in an amount of less than 6 wt.% based on the total weight of the composition, or may be present in an amount of less than 1.5 wt.% based on the total weight of the composition. If present in the composition, optional HCFC-243fa and HCFC-243db may be present in an amount of less than 3 wt.% based on the total weight of the composition.

[0010] After the reacting step, the method may additionally include the steps of distilling the composition in a distillation column; removing an overhead stream from the distillation column, which concentrates the overhead stream in HCFO-1233zd(E); and removing a bottoms stream from the distillation column, which concentrates the bottoms stream in HCFO-1233zd(Z) and HCFC-244fa. The method may further include the additional step of recycling the bottoms stream to the reactor after the second removal step. [Brief explanation of the drawings]

[0011] The above-mentioned and other features of the present disclosure, and the manner in which they are achieved, will become more apparent, and the disclosure itself will be better understood, by referring to the following description of embodiments of the present disclosure in light of the accompanying drawings.

[0012] [Figure 1] The following reactions are shown: (i) isomerization of HCFO-1233zd(Z) to form HCFO-1233zd(E), and (ii) dehydrohalogenation of HCFC-244fa to form HCFO-1233zd(E), hydrogen fluoride, and hydrogen chloride; and [Figure 2] FIG. 2 is a schematic diagram of a process for carrying out the reaction of FIG. 1.

[0013] Corresponding reference characters indicate corresponding parts throughout the several views. While the drawings depict embodiments of various features and components in accordance with the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated to better illustrate and explain the present disclosure. The exemplifications set forth herein are illustrative of embodiments of the present disclosure, and such exemplifications should not be construed as limiting the scope of the invention in any manner. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present disclosure provides a method for producing HCFO-1233zd by reacting a mixture containing HCFO-1233zd(Z) and HCFC-244fa in the vapor phase in the presence of a catalyst to simultaneously isomerize HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenate HCFC-244fa to form HCFO-1233zd(E). A method for converting a composition containing 1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E) is provided. The catalyst may be a chromium-based catalyst such as, for example, chromium trifluoride, chromium oxyfluoride, or chromium oxide.

[0015] Referring to FIG. 1 , the isomerization of HCFO-1233zd(Z) (i.e., cis-HCFO-1233zd or c-HCFO-1233zd) to form HCFO-1233zd(E) (i.e., trans-HCFO-1233zd or t-HCFO-1233zd) is shown in reaction (i), and the dehydrohalogenation of HCFC-244fa to form HCFO-1233zd(E), hydrogen fluoride, and hydrogen chloride is shown in reaction (ii). In accordance with the present disclosure, it has been discovered that both of the aforementioned reactions can be carried out simultaneously using the same catalyst. Specifically, the present disclosure introduces a manufacturing process for converting a mixture of HCFO-1233zd(Z) and HCFC-244fa to HCFO-1233zd(E) by heterogeneous vapor-phase catalysis.

[0016] A schematic diagram of a process for carrying out the present reaction is shown in Figure 2. Input stream 10 containing HCFO-1233zd(Z) and HCFC-244fa is provided to reactor 12. The HCFO-1233zd(Z) and HCFC-244fa in input stream 10 may be present in any desired amounts relative to each other and / or relative to the total weight of the entire mixture, although it may be desirable to limit the total amount of HCFC-244fa in input stream 10 to avoid the formation of certain by-products, as described below.

[0017] Input Stream 10 may itself be a fraction obtained from a commercial production process for preparing HCFO-1233zd(E). In this regard, Input Stream 10 may also contain any amount of HCFO-1233zd(E) that does not affect the conversion of HCFO-1233zd(Z) and HCFC-244fa present in Input Stream 10 to HCFO-1233zd(E). Alternatively, Input Stream 10 may be a recycle stream from a distillation column described below that contains unreacted HCFO-1233zd(Z) and HCFC-244fa. Input Stream 10 may also be a combination of the foregoing.

[0018] Input stream 10 may also contain trace amounts of other impurities, such as, for example, HCFC-243fa and HCFC-243db, and it has been found that the presence of less than 3 wt. % of HCFC-243fa and HCFC-243db in a mixture of HCFO-1233zd(Z) and HCFC-244fa, based on the total weight of the composition of stream 10, has little or no significant effect on the product distribution.

[0019] The impurities in input stream 10, specifically the total amount of all compounds other than HCFO-1233zd(Z), HCFC-244fa, and HCFO-1233zd(E) in input stream 10, may be less than 10 wt.%, less than 8 wt.%, less than 6 wt.%, or even less than 1.5 wt.%, based on the total weight of all compounds in the input stream, with higher levels of impurities being undesirable for extended periods of operation because higher concentrations can potentially result in a loss of catalyst activity over time.

[0020] In the reactor 12, HCFO-1233zd(Z) and HCFC-244fa are vaporized and reacted in the gas phase in the presence of a catalyst such as a heterogeneous catalyst, which is a solid catalyst in this reaction.

[0021] Suitable chromium-based catalysts include chromium oxide, chromium oxyfluoride, and chromium halides. Chromium oxide may include amorphous chromium oxide (Cr2O3), crystalline chromium oxide, and combinations thereof. Chromium oxyfluoride may include fresh amorphous chromium oxide (Cr2O3) pretreated with HF, fresh crystalline chromium oxide (Cr2O3) pretreated with HF, amorphous chromium oxyfluoride (Cr x O y F z , where x is 1 or 2, y may be 1 or 2, and z may be 1, 2, or 4), crystalline chromium oxyfluoride (Cr x O y F z , where x can be 1 or 2, y can be 1 or 2, and z can be 1, 2, or 4, and combinations thereof. In one embodiment, the catalyst is amorphous chromium oxyfluoride (Cr x O y F z (wherein x can be 1 or 2, y can be 1 or 2, and z can be 1, 2, or 4). Chromium halides can include chromium trifluoride (CrF), chromium trichloride (CrCl), chromium triiodide (CrI), and chromium tribromide (CrBr), and combinations thereof. In one embodiment, the catalyst is chromium trifluoride (CrF).

[0022] In addition to chromium-based catalysts, other suitable catalysts include other metal halides such as nickel fluoride, titanium fluoride, molybdenum fluoride, cobalt fluoride, aluminum fluoride, and combinations of the foregoing.

[0023] Suitable reaction temperatures in reactor 12 may be, for example, as low as 100°C, 125°C, 150°C, 175°C, or as high as 200°C, 225°C, 250°C, or 275°C, or within any range defined between any pair of the aforementioned values, such as 100°C to 275°C, 125°C to 250°C, 150°C to 225°C, or 175°C to 200°C.

[0024] Advantageously, when chromium trifluoride (CrF) is used as the catalyst, the simultaneous isomerization and dehydrohalogenation reactions of the present invention can be carried out to achieve effective conversions and selectivities at relatively low temperatures, for example, 80°C, 100°C, or 125°C, or as high as 175°C, 200°C, or 250°C, or within any range defined between any pair of the aforementioned values, such as 80°C to 250°C, 100°C to 200°C, or 125°C to 175°C.

[0025] Suitable reaction pressures in reactor 12 may be, for example, as low as 0 psig, 25 psig, 50 psig, or 75 psig, or as high as 100 psig, 125 psig, or 150 psig, or within any range defined between any pair of the aforementioned values, such as 0 psig to 150 psig, 25 psig to 125 psig, or 50 psig to 100 psig, etc. In one embodiment, the reaction pressure in the reactor is about 50 psig.

[0026] The amount of catalyst used can vary, but generally, the contact time between stream 10 and the catalyst in reactor 12 can be, for example, as little as 1 second, 25 seconds, or 50 seconds, or as long as 100 seconds, 125 seconds, or 150 seconds, or within any range defined between any pair of the foregoing values, such as 1 second to 150 seconds, 25 seconds to 125 seconds, or 50 seconds to 100 seconds.

[0027] The presence of water or water vapor in reactor 12 can have a detrimental effect on chromium-based catalysts, leading to rapid catalyst deactivation. Thus, the input stream and / or mixture in reactor 12 may contain, for example, less than 0.0050 wt. % (50 ppm) water, less than 0.0030 wt. % (30 ppm) water, or less than 0.0020 wt. % (20 ppm) water.

[0028] One by-product that may be produced during the simultaneous isomerization and dehydrohalogenation of HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E), respectively, is 1,1,1,3,3-pentafluoropropane (HFC-245fa). The formation of HFC-245fa results in reduced yields due to the potential formation of a binary azeotrope between HCFO-1233zd(E) and HFC-245fa. However, it has been found that when the reaction mixture contains less than 15 wt. % HCFC-244fa, the selectivity to the undesired by-product, HFC-245fa, may be limited to less than 5%. It was served.

[0029] In addition to HFC-245fa, hydrofluoric acid and hydrochloric acid are produced from the dehydrohalogenation reaction of HCFC-244fa. Referring to Figure 2, these acids produced during the reaction can be neutralized without affecting the distribution of products and by-products by passing the product stream through a caustic scrubber 14 using, for example, a 10 wt% aqueous sodium hydroxide solution 16, although other caustic (basic) solutions at other concentrations may also be used. After passing through the caustic scrubber 14, the composition may be passed through a dryer 18 containing a suitable desiccant to remove moisture.

[0030] In addition to HFC-245fa, other by-products may include HCFC-243fa and both isomers of 1,3,3,3-tetrafluoropropene (HFO-1234ze(Z) and HFO-1234ze(E)). With the exception of HFC-245fa, which may form a binary azeotrope with HCFO-1233zd(E), all other by-products can be readily separated from the HCFO-1233zd(E) product by conventional upstream use of distillation column 20, where the by-products are removed in either overhead stream 22 or bottoms stream 24 depending on their boiling point, as shown in FIG.

[0031] The HCFO-1233zd(E) product is concentrated in overhead stream 22, meaning that more HCFO-1233zd(E) product is present in overhead stream 22 than in bottoms stream 24, and any remaining unreacted HCFO-1233zd(Z) and HCFC-244fa are concentrated in bottoms stream 24, meaning that more HCFO-1233zd(Z) and HCFC-244fa is present in bottoms stream 24 than in overhead stream 22. Optionally, unreacted HCFO-1233zd(Z) and HCFC-244fa may be returned to reactor 12 via recycle stream 26.

[0032] Advantageously, in the present process, the conversion of HCFO-1233zd(Z) to HCFO-1233zd(E) during the simultaneous isomerization of HCFO-1233zd(Z) and dehydrohalogenation of HCFC-244fa may be greater than 88%, greater than 90%, greater than 93%, greater than 95%, or up to 96%, and the conversion of HCFC-244fa to HCFO-1233zd(E) during the simultaneous isomerization of HCFO-1233zd(Z) and dehydrohalogenation of HCFC-244fa may be greater than 99%, 90%, greater than 92%, greater than 95%, greater than 97%, and up to 96% or 99%.

[0033] The process may also provide a selectivity to HCFO-1233zd(E) of greater than 90%, greater than 92%, greater than 95%, greater than 96%, or up to 97% based on simultaneous HCFO-1233zd(Z) isomerization and HCFC-244fa dehydrohalogenation. [Example]

[0034] Simultaneous isomerization and dehydrohalogenation using CrF3 catalyst A feed stream consisting of HCFO-1233zd(Z), HCFC-244fa, and HCFO-1233zd(E) was vaporized and reacted in the vapor phase over a CrF catalyst to produce HCFO-1233zd(E). Specifically, the feed consisted of approximately 77 GC area % HCFO-1233zd(Z), 7.97 GC area % HCFC-244fa, and 13.89 GC area % HCFO-1233zd(E) and was vaporized and fed to a 1-inch reactor containing 0.28 L of CrF pellets at a rate of 0.3 lb / hr (136 g / hr) and a reactor pressure of 50 psig. The reaction temperature was varied from 100°C to 220°C. The average productivity observed was 27.725 lb / hr (1.26 kg / hr) of HCFO-1233zd(E) per cubic foot (0.028 cubic meter) of CrF catalyst. Table 1 shows the productivity of HCFO-1233zd(Z) and HCFO-1233zd(E) as a function of temperature using a CrF catalyst. The average conversion of C-244fa and the average selectivity to HCFO-1233zd(E) and by-products are shown.

[0035] [Table 1] [Example]

[0036] Simultaneous isomerization and dehydrohalogenation using amorphous chromium oxyfluoride catalysts A feed stream consisting of HCFO-1233zd(Z), HCFC-244fa, and HCFO-1233zd(E) was vaporized and reacted in the vapor phase over an amorphous chromium oxyfluoride catalyst to produce HCFO-1233zd(E). Specifically, the feed consisted of approximately 91.70 GC area % HCFO-1233zd(Z), 7.99 GC area % HCFC-244fa, and 0.278 GC area % HCFO-1233zd(E) and was vaporized and fed to a 1-inch reactor containing 0.28 L of amorphous chromium oxyfluoride pellets at a rate of 0.3 lb / hr (136 g / hr) and a reactor pressure of 50 psig. The reaction temperature was varied from 125°C to 275°C. The average productivity observed was 24.7 lb / hr (11.21 kg / hr) of HCFO-1233zd(E) per cubic foot (0.028 cubic meter) of amorphous chromium oxyfluoride catalyst. Table 2 shows the average conversions of HCFO-1233zd(Z) and HCFC-244fa, and the average selectivities to HCFO-1233zd(E) and by-products as a function of temperature using the amorphous chromium oxyfluoride catalyst.

[0037] [Table 2] [Example]

[0038] Isomerization of HCFO-1233zd(Z) A feed stream consisting of HCFO-1233zd(Z) was vaporized and reacted in the vapor phase over an amorphous chromium oxyfluoride catalyst to produce HCFO-1233zd(E). Specifically, a feed consisting of greater than 99.50 GC area % HCFO-1233zd(Z) was vaporized and fed to a 1-inch reactor containing 0.28 L of amorphous chromium oxyfluoride pellets at a rate of 0.6 lb / hr (272 g / hr) and a reactor pressure of 50 psi. The reaction temperature was maintained between 220°C and 230°C. The average observed productivity was 55.7 lb / hr (25.3 kg / hr) of HCFO-1233zd(E) per cubic foot (0.028 cubic meter) of amorphous chromium oxyfluoride catalyst. Table 3 shows the average conversion of HCFO-1233zd(Z) as a function of time on stream and the average selectivity to HCFO-1233zd(E) and by-products using amorphous chromium oxyfluoride catalyst.

[0039] [Table 3] [Example]

[0040] Dehydrohalogenation of HCFC-244fa A feed stream consisting of HCFC-244fa was vaporized and reacted in the vapor phase over an amorphous chromium oxyfluoride catalyst to produce HCFO-1233zd(E). Specifically, a feed consisting of >99.50 GC area % HCFC-244fa was vaporized and fed to a 1-inch reactor containing 0.28 L of amorphous chromium oxyfluoride pellets at a rate of 0.3 lb / hr (136 g / hr) and a reactor pressure of 50 psig. The reaction temperature was maintained between 220°C and 230°C. The average observed productivity was 18.2 lb / hr (8.3 kg / hr) of HCFO-1233zd(E) per cubic foot (0.028 cubic meter) of amorphous chromium oxyfluoride catalyst. Table 4 shows the average conversion of HCFC-244fa as a function of time on stream and the average selectivity to HCFO-1233zd(E) and by-products using amorphous chromium oxyfluoride catalyst.

[0041] [Table 4] [Example]

[0042] Simultaneous isomerization and dehydrohalogenation in the presence of HCFC-243fa or HCFC-243db using amorphous chromium oxyfluoride catalysts A feed stream consisting of HCFO-1233zd(Z), HCFC-244fa, HCFO-1233zd(E), and HCFC-243fa or HCFC-243db was vaporized and reacted in the vapor phase over an amorphous chromium oxyfluoride catalyst to produce HCFO-1233zd(E). Specifically, the feed consisted of approximately 91.72 GC area % HCFO-1233zd(Z), 6.55 GC area % HCFC-244fa, 0.07 GC area % HCFO-1233zd(E), and <3 GC area % HCFC-243fa or HCFC-243db. The feed was vaporized and fed to a 1-inch reactor containing 0.28 L of amorphous chromium oxyfluoride pellets at a rate of 0.3 lb / hr (136 g / hr) and a reactor pressure of 50 psig. The reaction temperature was maintained between 220°C and 230°C. The average productivity observed was 54.5 lb / hr (24.7 kg / hr) of HCFO-1233zd(E) per cubic foot (0.028 cubic meter) of amorphous chromium oxyfluoride catalyst. Table 5 shows the average conversions of HCFO-1233zd(Z), HCFC-244fa, HCFC-243fa, and HCFC-243db as a function of time on stream, and the average selectivities to HCFO-1233zd(E) and by-products using the amorphous chromium oxyfluoride catalyst.

[0043] [Table 5]

[0044] While the present disclosure has been described in terms of exemplary designs, the present disclosure may be further modified within the spirit and scope of the present disclosure. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains.

Claims

1. 1. A process for co-converting a composition containing HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E), comprising: providing a composition comprising HCFO-1233zd(Z) and HCFC-244fa; The composition in the gas phase in the reactor is added with chromium trifluoride (CrF ３ ) reacting in the presence of a catalyst to simultaneously isomerize HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenate HCFC-244fa to form HCFO-1233zd(E).

2. 10. The method of claim 1, wherein the reacting step is carried out at a temperature of from 80°C to 250°C.

3. 3. The method of claim 2, wherein the reacting step is carried out at a temperature of from 100°C to 200°C.

4. 10. The method of claim 1, wherein the contact time between the composition and the catalyst is from 1 second to 150 seconds.

5. 5. The method of claim 4, wherein the contact time between the composition and the catalyst is from 25 seconds to 125 seconds.

6. 10. The method of claim 1, wherein the pressure in the reactor is from 25 psig to 100 psig.

7. 10. The method of claim 1, wherein the reactor contains less than 50 ppm water during the reacting step.

8. 10. The process of claim 1, wherein said reacting step achieves a conversion of 88% to 96% of HCFO-1233zd(Z) to HCFO-1233zd(E).

9. 10. The process of claim 1, wherein said reacting step achieves 90% to 99% conversion of HCFC-244fa to HCFO-1233zd(E).

10. 10. The process of claim 1, wherein the reaction step achieves a selectivity to HCFO-1233zd(E) of 90% to 97%.

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