Process for catalytic conversion of a mixture of HCFO-1233zd(Z) and HCFC-244fa to HCFO-1233zd(E)

Abstract

This invention provides a method for forming HCFO-1233zd(E) that reduces waste, improves overall yield, and lowers manufacturing costs. [Solution] A method for converting a composition containing HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E) by reacting a mixture containing HCFO-1233zd(Z) and HCFC-244fa in the gas phase in the presence of a catalyst, thereby simultaneously isomerizing HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenating HCFC-244fa to form HCFO-1233zd(E). The catalyst may be a chromium-based catalyst such as chromium trifluoride, chromium oxyfluoride, or chromium oxide.

Description

[Background technology]

[0001] 1. Areas of Disclosure This disclosure relates to a catalytic conversion process 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. Explanation of related technologies (E)-1-chloro-3,3,3-trifluoropropene (HCFO-1233zd(E), or 1233zd(E)) is a novel low-global-warming and non-ozone-depleting molecule with applications as a blowing agent, solvent, and refrigerant. The applications 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 fluorinating 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)) is produced as a byproduct along with approximately 2% to 10% by weight of 1-chloro-1,3,3,3-tetrafluoropropane (HCFC-244fa, or 244fa), with a ratio of HCFO-1233zd(E) to HCFO-1233zd(Z) of approximately 10 to 20:1. Unfortunately, the formation of HCFO-1233zd(Z) and HCFC244fa results in a decrease in yield.

[0003] Due to the similar boiling points of HCFO-1233zd(Z) and HCFC-244fa, corresponding mixtures of these compounds exhibit azeotropic properties, making it impossible to separate the two components by conventional distillation methods. Furthermore, while HCFO-1233zd(Z) is used as an alternative, higher-boiling point solvent, HCFC-244fa is particularly toxic, making long-term storage of mixtures of these compounds impossible. Consequently, mixtures of HCFC-244fa and HCFO-1233zd(Z) obtained from the commercial production of HCFO-1233zd(E) are typically transported to thermal oxidation facilities for disposal, incurring further production costs.

[0004] Therefore, there is a growing need to develop production applications for mixtures of HCFC-244fa and HCFO-1233zd(Z) in order to reduce waste, improve overall yield, and lower manufacturing costs. [Overview of the project]

[0005] This disclosure provides a method for converting a composition containing HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E) by reacting a mixture containing HCFO-1233zd(Z) and HCFC-244fa in the gas phase in the presence of a catalyst, thereby simultaneously isomerizing HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenating HCFC-244fa to form HCFO-1233zd(E). The catalyst may be a chromium-based catalyst such as chromium trifluoride, chromium oxyfluoride, or chromium oxide.

[0006] In one embodiment, the present invention is a method for simultaneously converting a composition containing HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E). The present invention provides a method comprising the steps of supplying a mixture containing HCFO-1233zd(Z) and HCFC-244fa, and simultaneously reacting the composition in the gas phase of a reactor in the presence of a chromium trifluoride (CrF3) catalyst to isomerize HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenating HCFC-244fa to form HCFO-1233zd(E).

[0007] The reaction process 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 process, the reactor may contain less than 50 ppm of water. The reaction process can achieve a conversion rate of 88% to 96% of HCFO-1233zd(Z) to HCFO-1233zd(E), a conversion rate of 90% to 99% of HCFC-244fa to HCFO-1233zd(E), and / or a selectivity for HCFO-1233zd(E) of 90% to 97%.

[0009] In the supply process, all impurities may be present in an amount of less than 10% by weight of the total weight of the composition, less than 6% by weight of the total weight of the composition, or less than 1.5% by weight of the total weight of the composition. Any HCFC-243fa and HCFC-243db present in the composition may be present in an amount of less than 3% by weight of the total weight of the composition.

[0010] After the reaction step, the method may further include the steps of: distilling the composition in a distillation column; removing the top flow from the distillation column and concentrating the top flow to HCFO-1233zd(E); and removing the bottom flow from the distillation column and concentrating the bottom flow to HCFO-1233zd(Z) and HCFC-244fa. The method may further include, after the second removal step, an additional step of recirculating the bottom flow back into the reactor. [Brief explanation of the drawing]

[0011] By considering the attached drawings and referring to the following description of embodiments of the present disclosure, the above and other characteristics of the present disclosure, as well as the ways in which they are achieved, will become clearer, and the present disclosure itself will be better understood.

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

[0013] Corresponding reference letters indicate corresponding parts across several figures. The drawings illustrate various characteristics and components in accordance with this disclosure, but the drawings are not necessarily to scale, and certain characteristics may be exaggerated to better illustrate and explain this disclosure. The examples described herein are illustrative of embodiments of this disclosure and should not be construed as limiting the scope of the invention in any way. [Modes for carrying out the invention]

[0014] This disclosure describes a method for reacting a mixture containing HCFO-1233zd(Z) and HCFC-244fa in the gas phase in the presence of a catalyst, thereby simultaneously isomerizing HCFO-1233zd(Z) to form HCFO-1233zd(E) and dehydrohalogenating HCFC-244fa to form HCFO-1233zd(E). A method is provided for forming HCFO-1233zd(E) by converting a composition containing 1233zd(Z) and HCFC-244fa. The catalyst may be a chromium-based catalyst such as chromium trifluoride, chromium oxyfluoride, or chromium oxide.

[0015] Referring to Figure 1, reaction (i) shows the isomerization of HCFO-1233zd(Z) (i.e., cis-HCFO-1233zd, or c-1233zd) to form HCFO-1233zd(E) (i.e., trans-HCFO-1233zd, or t-1233zd), and reaction (ii) shows the dehydrohalogenation of HCFC-244fa to form HCFO-1233zd(E), hydrogen fluoride, and hydrogen chloride. According to this disclosure, it has been found that both of the aforementioned reactions can be carried out simultaneously using the same catalyst. Specifically, this disclosure describes a manufacturing process for converting a mixture of HCFO-1233zd(Z) and HCFC-244fa to HCFO-1233zd(E) by heterogeneous gas-phase catalysis.

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

[0017] The input stream 10 may itself be a fraction obtained from a commercial production process for preparing HCFO-1233zd(E). In this regard, the 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 the input stream 10 to HCFO-1233zd(E). Alternatively, the input stream 10 may be a recirculated stream from the distillation column described below, containing unreacted HCFO-1233zd(Z) and HCFC-244fa. The input stream 10 may also be a combination of the above.

[0018] The input stream 10 may also contain trace amounts of other impurities, such as HCFC-243fa and HCFC-243db. Based on the total weight of the composition of stream 10, it was found that the presence of less than 3% by weight of HCFC-243fa and HCFC-243db in the mixture of HCFO-1233zd(Z) and HCFC-244fa had little to no significant effect on the distribution of the product.

[0019] The total amount of impurities in the input stream 10, specifically all compounds other than HCFO-1233zd(Z), HCFC-244fa, and HCFO-1233zd(E), may be less than 10% by weight, less than 8% by weight, less than 6% by weight, or even less than 1.5% by weight, based on the total weight of all compounds in the input stream. Higher concentrations of impurities can potentially lead to a loss of catalytic activity over time, and therefore, higher concentrations of impurities are undesirable for longer operating periods.

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

[0021] Suitable chromium-based catalysts include chromium oxide, chromium oxyfluoride, and chromium halide. Chromium oxide may include amorphous chromium oxide (Cr2O3), crystalline chromium oxide, and combinations thereof. As chromium oxyfluoride, 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 may be 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 may be 1 or 2, y may be 1 or 2, and z may be 1, 2, or 4), and combinations thereof. In one embodiment, the catalyst is amorphous chromium oxyfluoride (Cr x O y F z , where x may be 1 or 2, y may be 1 or 2, and z may be 1, 2, or 4). Chromium halides 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).

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

[0024] Advantageously, when using chromium trifluoride (CrF3) as the catalyst, the isomerization and dehydrohalogenation reactions of the present invention can be carried out at a relatively low temperature within any range defined between any pair of the aforementioned values, for example, 80°C, 100°C or 125°C, or up to 175°C, 200°C or 250°C, or 80°C to 250°C, 100°C to 200°C or 125°C to 175°C, etc., to achieve effective conversion and selectivity.

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

[0026] The amount of catalyst used can vary, but generally, the contact time between the stream 10 and the catalyst within the reactor 12 can be, for example, as short 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 aforementioned 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 steam within the reactor 12 can have a harmful effect on the chromium-based catalyst and may lead to rapid catalyst deactivation. Therefore, the input stream and / or mixture within the reactor 12 may contain, for example, less than 0.0050 wt% (50 ppm) of water, less than 0.0030 wt% (30 ppm) of water, or less than 0.0020 wt% (20 ppm) of water.

[0028] One by-product that may be generated during the simultaneous isomerization and dehydrohalogenation of HCFO-1233zd(Z) and HCFC-244fa to form HCFO-1233zd(E) is 1,1,1,3,3-pentafluoropropane (HFC-245fa). The formation of HFC-245fa results in a yield reduction due to the potential formation of a dicomponent azeotrope between HCFO-1233zd(E) and HFC-245fa. However, if the reaction mixture contains less than 15% by weight of HCFC-244fa, the selectivity for the undesirable 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, for example, by passing the product stream through a caustic scrubber 14 using a 10 wt% aqueous sodium hydroxide solution 16, although other caustic (basic) solutions of other concentrations may be used. After passing through the caustic scrubber 14, the composition may be passed through a dryer 18 containing a desiccant suitable for removing 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)). Except for HFC-245fa, which may form a dicomponent azeotrope with HCFO-1233zd(E), all other by-products can be easily separated from the HCFO-1233zd(E) product by a conventional upstream using a distillation column 20, as shown in Figure 2, in which the by-products are removed in either the top flow 22 or the bottom flow 24, depending on their boiling points.

[0031] The HCFO-1233zd(E) product is concentrated in the top flow 22, meaning that more HCFO-1233zd(E) product is present in the top flow 22 than in the bottom flow 24. Any remaining unreacted HCFO-1233zd(Z) and HCFC-244fa are concentrated in the bottom flow 24, meaning that more HCFO-1233zd(Z) and HCFC-244fa are present in the bottom flow 24 than in the top flow 22. Optionally, the unreacted HCFO-1233zd(Z) and HCFC-244fa may be returned to the reactor 12 via the recirculation flow 26.

[0032] Advantageously, in this process, the conversion rate 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%, and up to 96%, and the conversion rate 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] Furthermore, in this process, based on the simultaneous isomerization of HCFO-1233zd(Z) and dehydrohalogenation of HCFC-244fa, the selectivity for HCFO-1233zd(E) may be greater than 90%, greater than 92%, greater than 95%, greater than 96%, or up to 97%. [Examples]

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

[0035] [Table 1] [Examples]

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

[0037] [Table 2] [Examples]

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

[0039] [Table 3] [Examples]

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

[0041] [Table 4] [Examples]

[0042] Simultaneous isomerization and dehydrohalogenation using amorphous chromium oxyfluoride catalyst in the presence of HCFC-243fa or HCFC-243db. 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 gas phase on an amorphous chromium oxyfluoride catalyst to produce HCFO-1233zd(E). Specifically, a feed material consisting of approximately 91.72 GC area% of HCFO-1233zd(Z), 6.55 GC area% of HCFC-244fa, 0.07 GC area% of HCFO-1233zd(E), and <3 GC area% of HCFC-243fa or HCFC-243db was vaporized and supplied to a 1-inch reactor containing 0.28 L of amorphous chromium oxyfluoride pellets at a rate of 0.3 lb / hour (136 g / hour) and a reactor pressure of 50 psig. The reaction temperature was maintained at 220°C to 230°C. The observed average productivity was 54.5 lb / hour (24.7 kg / hour) of HCFO-1233zd(E) per cubic foot (0.028 cubic meters) of amorphous chromium oxyfluoride catalyst. Table 5 shows the average conversion rates of HCFO-1233zd(Z), HCFC-244fa, HCFC-243fa, and HCFC-243db as a function of time with respect to flow, as well as the average selectivity for HCFO-1233zd(E) and by-products, using amorphous chromium oxyfluoride catalyst.

[0043] [Table 5]

[0044] Although this disclosure has been described as relating to an exemplary design, this disclosure may be further modified within the spirit and scope of this disclosure. Furthermore, this application is intended to encompass such deviations from this disclosure that belong to known or customary practices in the art to which the invention relates.

Claims

1. A method for forming HCFO-1233zd(E) by simultaneously converting a composition containing HCFO-1233zd(Z) and HCFC-244fa, A step of supplying a composition containing HCFO-1233zd(Z) and HCFC-244fa, The composition in the gas phase inside the reactor is dissolved in chromium trifluoride (CrF ３ A method comprising the steps of reacting in the presence of a catalyst to isomerize HCFO-1233zd(Z) to form HCFO-1233zd(E), and simultaneously dehydrohalogenating HCFC-244fa to form HCFO-1233zd(E).

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

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

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

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

6. The method according to claim 1, wherein the pressure inside the reactor is 25 psig to 100 psig.

7. The method according to claim 1, wherein the reactor contains less than 50 ppm of water during the reaction step.

8. The method according to claim 1, wherein the reaction step achieves the conversion of 88% to 96% of HCFO-1233zd(Z) to HCFO-1233zd(E).

9. The method according to claim 1, wherein the reaction step achieves the conversion of 90% to 99% of HCFC-244fa to HCFO-1233zd(E).

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

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