Method for purifying fluoroolefin having =CF2 or =CHF structure, and high-purity fluoroolefin and method for producing same

Abstract

According to the present invention, impurities are removed from a fluoroolefin having a =CF2 or =CHF structure, the fluoroolefin containing, as the impurities, haloalkenes and / or haloalkanes and / or haloalkynes obtained by a dehydrohalogenation reaction.　Provided are: a method, for purifying the fluoroolefin having a =CF2 or =CHF structure, which includes a step for bringing into contact, with a solid adsorbent, the fluoroolefin having a =CF2 or =CHF structure and containing at least one type of impurity from among haloalkanes and / or haloalkenes and / or haloalkynes obtained by a dehydrohalogenation reaction, and adsorption-removing the impurities; a high-purity fluoroolefin; and a manufacturing method therefor.

Description

[Technical field]

[0001] The present invention relates to =CF 2 The present invention relates to a method for purifying a fluoroolefin having the structure =CHF, as well as a high-purity fluoroolefin and a method for producing the same. [Background technology]

[0002] Hydrofluoroolefins (HFOs) are known as desirable alternatives to HCFCs due to their low ODP (Ozone Depletion Potential) and GWP (Global Warming Potential) values. For example, 1,1,3,3,3-pentafluoropropene is known as a compound useful as a refrigerant, heat transfer fluid, fire extinguishing agent, propellant, foaming agent, blowing agent, gas derivative, polymerization medium or monomer.

[0003] It is known that 1,1,3,3,3-pentafluoropropene can be obtained by a dehydrohalogenation reaction. For example, Patent Document 1 discloses a method for producing 1,1,3,3,3-pentafluoropropene by thermal decomposition of 1,1,1,3,3,3-hexafluoropropane under catalyst-free conditions. In

[0002] of Patent Document 1, it is explained that when the raw material gas is thermally decomposed at high temperatures, a complex mixture that is difficult to separate is produced. However, in

[0007] of Patent Document 1, it is explained that 1,1,3,3,3-pentafluoropropene (CF 3 CH=CF 2 It also describes that the product is stable and is not converted to a product with fewer hydrogen and / or fluorine atoms. For this reason, Cited Document 1 does not describe the impurities that were problematic during the study by the present inventors.

[0004] The content of the by-produced haloalkanes and haloalkenes having chlorine or fluorine atoms bonded thereto must be easily and efficiently reduced in order to utilize them as coolants, heat transfer fluids, fire extinguishing agents, propellants, foaming agents, expanding agents, gas derivatives, polymerization media, or monomers.

[0005] Since haloalkanes and haloalkenes have boiling points close to that of 1,1,3,3,3-pentafluoropropene (approximately -21°C), separation by distillation is difficult, and reducing the content requires a distillation apparatus with a large number of stages, which increases the equipment costs and creates problems in terms of mass production.

[0006] Regarding tetrafluoropropene, which is particularly difficult to separate, the inventors' investigations have shown that a distillation column with a minimum theoretical plate number of 113 is required to obtain 1,1,3,3,3-pentafluoropropene of 99.99% or higher.

[0007] As a purification method by adsorption, Patent Document 2 discloses a method in which a fluid containing a fluoroolefin and an alkane having one carbon atom is contacted with synthetic zeolite 4A to remove the alkane having one carbon atom. Patent Document 3 discloses a method in which a (hydro)haloalkene impurity is contacted with a solid adsorbent (zeolite) having an opening of 7 to 10 Å in maximum dimension at a temperature of −20° C. to 100° C. to remove the (hydro)haloalkene impurity. Patent Document 4 discloses a process in which 2,3,3,3-tetrafluoropropene containing a (hydro)halocarbon compound is contacted with an aluminum-containing adsorbent, activated carbon, or a mixture thereof. Patent Document 5 discloses a method in which 1,1,1,3,3-pentafluoropropane containing halopropenes is contacted with a solid adsorbent (particularly activated carbon) to remove the halopropenes. Patent Document 6 discloses a purification method in which 2,3,3,3-tetrafluoropropene containing hydroalkene impurities and hydroalkane impurities is contacted with a molecular sieve having an effective pore size of 5 to 10 Å to remove at least a portion of the impurities. Patent Document 7 discloses a method for purifying a fluoroolefin by adsorbing and removing impurities having one or two carbon atoms from a fluid mixture containing a fluoroolefin having three or more carbon atoms.

[0008] Patent Document 8 describes molecular sieves (synthetic zeolite), silica gel, and activated alumina as dehydrating agents for dehydrating the distillate extracted from the distillation column. Patent Document 9 describes the use of 1,1,3,3,3-pentafluoropropene (1225zc) as a dehydrating agent because the boiling points are close to each other, i.e., =CH 2 It has been described that it is difficult to separate 1225zc from 3,3,3-trifluoropropene (1243zf), which has the structure shown below, and that the use of activated carbon adsorbent to separate 1225zc from 1243zf has been described. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Special Publication No. 2008-518938 [Patent Document 2] WO2013 / 151070 publication [Patent Document 3] Patent No. 4121745 [Patent Document 4] Patent No. 6074454 [Patent Document 5] JP 2002-226411 A [Patent Document 6] JP 2012-1495 A [Patent Document 7] JP 2013-241390 A [Patent Document 8] WO2013 / 099856 publication [Patent Document 9] Special Publication No. 2013-508265 Summary of the Invention [Problem to be solved by the invention]

[0010] However, Patent Document 2 is a method for removing hydroalkanes having one carbon atom, Patent Document 7 is a method for purifying fluoroolefins by removing impurities having one or two carbon atoms, Patent Documents 3 and 5 are methods for removing (hydro)haloalkene impurities, but are purification methods from saturated hydrofluorocarbons, and Patent Documents 4 and 6 are methods for removing =CH 2 This is a method for removing hydrohaloalkanes and hydrohaloalkene impurities contained in 2,3,3,3-tetrafluoropropene (1234yf), which has the structure shown below. No method was known for adsorbing and removing impurities including haloalkenes and haloalkanes with three carbon atoms, which have similar boiling points.

[0011] For example, in the synthesis reaction under high temperature conditions shown above, =CF 2 When producing fluoroolefins having 3 or more carbon atoms, such as 1,1,3,3,3-pentafluoropropene having the structure of the formula (1), haloalkanes having 1 carbon atom, and various haloalkanes and haloalkenes having 2 carbon atoms are by-produced with haloalkanes and haloalkenes having 3 carbon atoms, which have a closer boiling point. The present inventors have found that, in order to obtain the desired fluoroolefins having 3 or more carbon atoms in as high a yield as possible, it is necessary to efficiently remove haloalkanes and haloalkene impurities having 3 carbon atoms, which have a closer boiling point, in addition to haloalkanes having 1 carbon atom, haloalkanes and haloalkenes having 2 carbon atoms. However, the current situation is that no method is known for adsorbing and removing only undesirable haloalkanes and haloalkene impurities having 3 carbon atoms from a mixture containing fluoroolefins having 3 or more carbon atoms.

[0012] The present invention provides a method for the adsorption and removal of impurities including haloalkanes, haloalkenes, and haloalkynes having similar boiling points, thereby obtaining a product of =CF 2 Another object of the present invention is to provide a method for efficiently purifying a fluoroolefin having a =CHF structure to obtain a fluoroolefin with a higher purity. [Means for solving the problem]

[0013] The present invention provides the following: [1] =CF containing at least one of haloalkane, haloalkene and haloalkyne impurities obtained by dehydrohalogenation reaction 2 or a step of contacting a fluoroolefin having the structure of =CHF with a solid adsorbent to adsorb and remove the impurities. 2 Or a method for purifying a fluoroolefin having the structure =CHF. [2] The method according to [1], wherein the effective pore size of the solid adsorbent is 3 to 50 Å. [3] The method according to [1] or [2], wherein the solid adsorbent is at least one selected from the group consisting of activated carbon, molecular sieves type A or type X, and activated alumina. [4] The method according to any one of [1] to [3], wherein the total content of the impurities in the fluoroolefin containing the impurities is more than 0 ppm and 10 mass % or less. [5] The method according to any one of [1] to [4], wherein the fluoroolefin containing the impurities is contacted with a solid adsorbent for a contact time of up to 60 minutes. [6] =CF containing at least one of haloalkane, haloalkene and haloalkyne impurities obtained by dehydrohalogenation reaction 2 or a high-purity =CF, which comprises a step of contacting a fluoroolefin having the structure =CHF with a solid adsorbent to adsorb and remove the impurities. 2 Or a method for producing a fluoroolefin having the structure =CHF. [7] The method according to [6], wherein the effective pore size of the solid adsorbent is 3-50 Å. [8] The method according to [6] or [7], wherein the solid adsorbent is at least one selected from the group consisting of activated carbon, molecular sieves type A or type X, and activated alumina. [9] The method according to any one of [6] to [8], wherein the total content of the impurities in the impurity-containing fluoroolefin is more than 0 ppm and not more than 10 mass %.

[10] The method according to any one of [6] to [9], wherein the fluoroolefin containing the impurities is contacted with a solid adsorbent for a contact time of up to 60 minutes.

[11] 1,1,3,3,3-Pentafluoropropene with a purity of 99.9% or higher.

[12] 1,1,3,3,3-Pentafluoropropene containing 0 to 100 ppm of tetrafluoropropene as an impurity. Effect of the Invention

[0014] The present invention =CF 2 According to a method for purifying a fluoroolefin having the structure =CF or =CHF, haloalkane and / or haloalkene and / or haloalkyne impurities, particularly haloalkane and / or haloalkene and / or haloalkyne impurities having a chlorine atom or a fluorine atom bonded thereto, are removed, and =CF 2 Alternatively, the purity of the fluoroolefin having the =CHF structure can be increased. Furthermore, according to the production method of the present invention, a high-purity fluoroolefin can be obtained by purifying the fluoroolefin as described above. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of an example of an apparatus for carrying out the purification method of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of another example of an apparatus for carrying out the purification method of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] <effect> The present invention relates to a =CF alkane, haloalkene and / or haloalkyne impurity obtained by a dehydrohalogenation reaction, which contains at least one kind of haloalkane, haloalkene and / or haloalkyne impurity having a chlorine atom or a fluorine atom bonded thereto. 2 or a fluoroolefin having the structure of =CHF is brought into contact with a solid adsorbent to adsorb and remove the impurities. 2 The present invention provides a method for purifying and producing a fluoroolefin having the structure =CF or =CHF. 2 Or, it is a fluoroolefin having the structure =CHF. =CF 2 Or, the fluoroolefin with the structure =CHF is =CH 2 As a result of the studies by the present inventors, it has become possible to produce a high purity =CF 2 It was surprising that it became possible to produce fluoroolefins having the structure =CHF. More specifically, impurities that were difficult to separate using a distillation column with 40 theoretical plates, particularly C3 compounds with a small boiling point difference, can be preferentially removed to obtain high-purity 1,1,3,3,3-pentafluoropropene (particularly, having a purity of 99.9% or more). According to the present invention, 1,3,3,3-tetrafluoropropene, which is particularly difficult to separate by distillation and is the main impurity, is not detected by venting the adsorption column.

[0017] Hereinafter, an embodiment of the present invention will be described. <Fluoroolefin purification method> The first embodiment of the present invention is a process for producing a fluorine- or chlorine-containing alkane-based alkene ... 2or =CHF, the haloalkane, haloalkene and haloalkyne impurities being removed from the fluoroolefin, which is characterized by contacting the fluid with a solid adsorbent.

[0018] (Fluoroolefin) The fluoroolefin to be purified is preferably a fluoroolefin having 3 or 4 carbon atoms. Specific examples include hexafluoropropene, pentafluoropropene, tetrafluoropropene, trifluoropropene, octafluorobutene, hexafluorobutene, and tetrafluorobutadiene. That is, a mixture containing one or more fluoroolefins selected from the group consisting of the above compounds is purified in the present invention. Here, examples of the pentafluoropropene include 1,1,2,3,3-pentafluoropropene and 1,1,3,3,3-pentafluoropropene. Examples of the tetrafluoropropene include 1,1,3,3-tetrafluoropropene and 1,2,3,3-tetrafluoropropene, and examples of the trifluoropropene include 1,3,3-trifluoropropene, 1,1,3-trifluoropropene, and 1,2,3-trifluoropropene. Examples of the octafluorobutene include octafluoro-1-butene. Examples of hexafluorobutene include 1,1,3,3,4,4,4-hexafluoro-1-butene, 1,2,3,3,4,4,4-hexafluoro-1-butene, etc. Examples of tetrafluorobutadienes include 1,1,4,4-tetrafluoro-1,3-butadiene, etc.

[0019] The fluoroolefin in the present invention may be a reaction product obtained by a synthesis reaction involving thermal decomposition under high temperature conditions, particularly at 400 to 1000° C. Examples of such synthesis reactions include a reaction in which 1,1,1,3,3,3-hexafluoropropane is thermally decomposed at a temperature of 400 to 1000° C., and more specifically, the following can be mentioned. (1) A reaction in which 1,1,1,3,3,3-hexafluoropropane is thermally decomposed at temperatures of 600 to 1000°C in a hollow reaction tube made of metal such as nickel, Hastelloy, Monel, or Inconel. (2) A reaction in which 1,1,1,3,3,3-hexafluoropropane is thermally decomposed at a temperature of 600 to 1000°C in a metal reaction tube filled with a metal filler such as nickel or Hastelloy. (3) CrF using 1,1,1,3,3,3-hexafluoropropane as a catalyst 3 / C or AlF 3 / C or RuF 3 / C or PtF 2 A reaction in which the material is thermally decomposed at temperatures of 400 to 800°C in a metal reaction tube made of nickel, Hastelloy, etc., filled with a metal catalyst such as / C.

[0020] It is desirable to remove impurities from the reaction product by distillation before subjecting the reaction product to the purification method of the present invention.

[0021] (Haloalkane impurities) The haloalkane impurity contained in the fluoroolefin and removed in the present invention is preferably a haloalkane having 1, 2 or 3 carbon atoms, more preferably a haloalkane having 2 or 3 carbon atoms. Specific examples include hydrofluoroethane and hydrofluoropropane, and more specific examples include tetrafluoroethane, pentafluoropropane, and hexafluoropropane.

[0022] (Haloalkene impurities) Examples of haloalkene impurities contained in the fluoroolefin and removed in the present invention include, for example, pentafluoropropenes such as (Z) 1,2,3,3,3-pentafluoropropene and (E) 1,2,3,3,3-pentafluoropropene, tetrafluoropropenes such as 1,3,3,3-tetrafluoropropene, trifluoropropenes such as 3,3,3-trifluoropropene, octafluorobutenes such as octafluoro-2-butene, and hexafluorobutenes such as 1,1,1,4,4,4-hexafluoro-2-butene, 2,3,3,4,4,4-hexafluoro-1-butene, and 2-(trifluoromethyl)-3,3,3-trifluoro-1-propene.

[0023] (Haloalkyne impurities) Haloalkyne impurities contained in the fluoroolefin and removed in the present invention include, for example, trifluoropropyne such as 1,3,3-trifluoropropyne and 3,3,3-trifluoropropyne, and hexafluorobutyne such as 1,1,1,4,4,4-hexafluoro-2-butyne.

[0024] (Solid adsorbent) Examples of the solid adsorbent in the present invention include activated carbon, zeolite A or X type, activated alumina, silica gel, and the like. Among them, zeolite is preferred from the viewpoint of removing impurities. The cationic species of zeolite are preferably potassium ion, sodium ion, and calcium ion. Examples of zeolite include zeolite MS-3A (effective pore size: 3 Å, KA type), zeolite MS-4A (effective pore size: 4 Å, NaA type), zeolite MS-5A (effective pore size: 5 Å, CaA type), and zeolite MS-13X (effective pore size: 10 Å, NaA type). The effective pore size of the solid adsorbent is preferably 3 to 50 Å, more preferably 3 to 20 Å, and even more preferably 5 to 10 Å.

[0025] Before being used for purification, the solid adsorbent is preferably heat-treated with a dry gas (particularly nitrogen gas) at 100° C. to 350° C., or in a container under reduced pressure at 100° C. to 350° C. This activates the solid adsorbent and improves the efficiency of removing impurities.

[0026] (Contact between fluoroolefin and solid adsorbent) The pressure conditions of the fluoroolefin when contacting with the solid adsorbent are not particularly limited. Usually, atmospheric pressure to 0.5 MPa (gauge pressure) is adopted. The temperature conditions are preferably 0°C to 200°C, more preferably 0°C to 100°C. The longer the contact time between the solid adsorbent and the mixed gas, the higher the adsorption efficiency of the solid adsorbent is, and the easier it is to obtain a high-purity fluoroolefin. The shorter the contact time, the higher the processing capacity is, and the more efficiently the fluoroolefin can be purified.

[0027] From the viewpoint of the efficiency of removing haloalkane, haloalkene, and haloalkyne impurities, the total content of haloalkane, haloalkene, and haloalkyne impurities contained in the fluoroolefin before purification is preferably 10 mass% or less, more preferably 5 mass% or less, and most preferably 1 mass% or less.

[0028] (purification equipment) Examples of materials for the refining device include corrosion-resistant metals such as stainless steel, Inconel, Monel, Hastelloy, and nickel.

[0029] An example of a purification device that can be applied to the present invention is shown in FIG. 1. In FIG. 1, the thermal decomposition reactor 2 is a cylindrical tube made of nickel, and a heater 3 is arranged around the outer periphery of the reactor 2 so that the entire reactor 2 can be uniformly heated. In FIG. 1, the reactor 2 is arranged as a cylindrical tube standing vertically, and the raw material gas from the raw material tank 1 passes through the inside of the reactor 2 from the top to the bottom through a pipe. A gas scrubbing tower 4 is arranged downstream of the reactor 2 to remove by-products such as hydrogen halides and high boiling point compounds generated by the thermal decomposition reaction. A distillation tower 5 is arranged downstream of the gas scrubbing tower 4, and low boiling point compounds and high boiling point compounds are removed by distillation. The purified product containing impurities that has passed through the distillation tower 5 is stored in a collection vessel 6. An adsorption purification tower 7 is arranged downstream of the collection vessel 6. The collection vessel 6 is designed to reduce the difference in processing speed between the distillation tower 5 and the adsorption purification tower 7. The adsorption purification tower 7 is constructed by standing a cylindrical tube made of nickel vertically and filling the inside with a solid adsorbent. The refined product containing impurities from collection vessel 6 passes through piping from the bottom to the top of adsorption refinement tower 7. Impurities that are difficult to separate by distillation are removed by the solid adsorbent in adsorption refinement tower 7, and the adsorbed refined product is recovered in refined product storage tank 8.

[0030] Another example of a purification apparatus applicable to the present invention is shown in Figure 2. In Figure 2, the crude product that has passed through the gas washing tower 4 has moisture removed in a drying tower 9, and then passes first through an adsorption purification tower 7, and is then distilled in a distillation tower 5 to recover an adsorbed purified product in a purified product storage tank 8. That is, in the purification apparatus of Figure 2, impurities that cannot be separated in the distillation tower 5 are first separated in the adsorption purification tower 7. Since solid adsorbents tend to adsorb moisture and reduce the adsorption efficiency, it is desirable to place a drying tower 9 upstream of the adsorption purification tower 7.

[0031] (Production method and product of the present invention) According to the present invention, there is also provided a method for producing a ═CF olefin-based olefin containing at least one of haloalkane, haloalkene and haloalkyne impurities, particularly at least one of haloalkane, haloalkene and haloalkyne impurities having a chlorine atom or a fluorine atom bonded thereto, which is obtained by a dehydrohalogenation reaction. 2 or a high-purity =CF, which comprises a step of contacting a fluoroolefin having the structure =CHF with a solid adsorbent to adsorb and remove the impurities. 2 Alternatively, a method for producing a fluoroolefin having the structure =CHF is provided.

[0032] The step of contacting the fluoroolefin with the solid adsorbent in the above-mentioned production method of the present invention is as described above in the purification method of the present invention, and the above-mentioned production method of the present invention provides a high-purity fluoroolefin, particularly one having an impurity concentration of 100 ppm or less, particularly 0 to 10 ppm after purification. In the dehydrohalogenation reaction, many impurities (particularly, the total content of impurities is more than 0 ppm and 10 mass % or less) are formed in addition to the target product. The production method of the present invention can provide a high-purity fluoroolefin such as 1,1,3,3,3-pentafluoropropene containing tetrafluoropropene as an impurity in an amount of 0 to 100 ppm. The purity of the fluoroolefin obtained by the production method of the present invention is 99% or more, particularly 99.5% or more, particularly 99.9% or more, particularly 99.99% or more, and as far as the applicant knows, a fluoroolefin of such a high purity has not been obtained by a conventional method. EXAMPLES

[0033] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto. In the following, the composition of the mixture was determined from GC area % by gas chromatography (GC-MS or GC-FID). Comparative Example 1 <Fluoropropene manufacturing method> 1,1,1,3,3,3-Hexafluoropropane was used as the raw material, and a 3B x 1500 mm nickel tube was heated to 800°C with a resistance heater, and the raw material was introduced at a flow rate of 9.0 SLM. The gas obtained from the reactor outlet was treated with pure water and an alkaline aqueous solution to obtain 1,1,3,3,3-pentafluoropropene and a mixture of impurities shown in Table 1.

[0034] This mixture was subjected to rectification treatment in a rectification column having 40 theoretical plates, and as a result, a refined product containing 98.25% 1,1,3,3,3-pentafluoropropene impurity with the composition shown in Table 1, i.e., 0.04% 1,1,1-trifluoroethane, 0.26% 1,1,1,2-tetrafluoroethane, 0.11% 3,3,3-trifluoropropene, 0.41% (Z) 1,2,3,3,3-pentafluoropropene, 0.05% (E) 1,2,3,3,3-pentafluoropropene, 0.52% (E) 1,3,3,3-tetrafluoropropene, and 0.37% 1,1,1,3,3,3-hexafluoropropane, was obtained.

[0035] Example 1 An adsorption purification tower was prepared by sealing 27.6 g of zeolite MS-3A (Zeolum A-3 4-8 mesh, manufactured by Tosoh Corporation) as a solid adsorbent in a φ12A×500 mm tube made of SUS304 and drying it for 12 hours at an internal temperature of 100° C. with heated nitrogen. The refined product containing 1,1,3,3,3-pentafluoropropene impurities with a purity of 98.25% obtained in Comparative Example 1 was introduced into this adsorption purification tower, and the gas composition before introduction was compared with the gas composition obtained in the latter stage of the adsorption purification tower. The 1,1,3,3,3-pentafluoropropene obtained from the rear of the adsorption purification column contained 0.02% 1,1,1-trifluoroethane, 0.08% 1,1,1,2-tetrafluoroethane, 0.02% 3,3,3-trifluoropropene, 0.15% (Z) 1,2,3,3,3-pentafluoropropene, 0.02% (E) 1,2,3,3,3-pentafluoropropene, and 0.19% 1,1,1,3,3,3-hexafluoropropane, with a purity of 99.52%.

[0036] Example 2 Zeolite MS-4A (Zeolum A-4 4-8 mesh, manufactured by Tosoh Corporation) was filled in a SUS304 tube of φ12A×500mm as a solid adsorbent, and dried for 12 hours at an internal temperature of 100°C with heated nitrogen to prepare an adsorption purification tower. The purified product containing 1,1,3,3,3-pentafluoropropene impurities with a purity of 98.25% and containing impurities obtained in Comparative Example 1 was introduced into this adsorption purification tower, and the gas composition before introduction and the gas composition obtained in the latter stage of the adsorption purification tower were compared. The 1,1,3,3,3-pentafluoropropene obtained from the latter stage of the adsorption purification tower contained 0.26% (Z)1,2,3,3,3-pentafluoropropene, and its purity was 99.74%.

[0037] Example 3 An adsorption purification tower was prepared by sealing 24.8 g of zeolite MS-5A (Zeolum A-5 4-8 mesh, manufactured by Tosoh Corporation) as a solid adsorbent in a φ12A×500 mm tube made of SUS304 and drying it for 12 hours at an internal temperature of 100° C. with heated nitrogen. The refined product containing 1,1,3,3,3-pentafluoropropene impurities with a purity of 98.25% obtained in Comparative Example 1 was introduced into this adsorption purification tower, and the gas composition before introduction was compared with the gas composition obtained in the latter stage of the adsorption purification tower. The 1,1,3,3,3-pentafluoropropene obtained from the rear of the adsorption purification column contained 0.04% 1,1,1-trifluoroethane, 0.06% 1,1,1,2-tetrafluoroethane, 0.06% 3,3,3-trifluoropropene, 0.23% (Z)1,2,3,3,3-pentafluoropropene, and 0.13% 1,1,1,3,3,3-hexafluoropropane, with a purity of 99.48%.

[0038] Example 4 Zeolite MS-13X (Zeolum F-9 4-8 mesh, manufactured by Tosoh Corporation) was filled in a SUS304 tube of φ12A×500mm as a solid adsorbent, and dried for 12 hours at an internal temperature of 100°C with heated nitrogen to prepare an adsorption purification tower. The purified product containing 1,1,3,3,3-pentafluoropropene impurity with a purity of 98.25% and containing impurities obtained in Comparative Example 1 was introduced into this adsorption purification tower, and the gas composition before introduction and the gas composition obtained in the latter stage of the adsorption purification tower were compared. The 1,1,3,3,3-pentafluoropropene obtained from the latter stage of the adsorption purification tower contained 0.02% 1,1,1-trifluoroethane and had a purity of 99.98%.

[0039] Example 5 A tube made of SUS304, φ12A×500mm, was filled with 23.7g of activated alumina (Axens, activated alumina grade D 2-5mm) as a solid adsorbent, and dried with heated nitrogen at an internal temperature of 100°C for 12 hours to prepare an adsorption purification tower. The purified product containing 1,1,3,3,3-pentafluoropropene impurities with a purity of 98.25% obtained in Comparative Example 1 was introduced into this adsorption purification tower, and the gas composition before introduction and the gas composition obtained in the latter stage of the adsorption purification tower were compared. The 1,1,3,3,3-pentafluoropropene obtained in the latter stage of the adsorption purification tower did not contain any impurities, and its purity was 100%.

[0040] [Table 1]

[0041] As can be seen from Table 1, according to the present invention, haloalkanes and / or haloolefins can be significantly removed, and the purity of the product to be purified can be increased to 99% or more. In particular, when alumina or zeolite with an effective pore size of 10 Å was used, the effect of removing impurities was remarkable (Examples 4 and 5). According to the present invention, impurities that are difficult to separate using a distillation tower with 40 theoretical plates, particularly C3 compounds with a small boiling point difference, can be preferentially removed to obtain high-purity 1,1,3,3,3-pentafluoropropene. According to the present invention, 1,3,3,3-tetrafluoropropene, which is particularly difficult to separate by distillation and is the main impurity, is not detected by venting the adsorption tower.

Claims

1. CF3, which contains at least one of haloalkane, haloalkene and haloalkyne impurities obtained by dehydrohalogenation reaction ２ or a step of contacting a fluoroolefin having the structure of =CHF with a solid adsorbent to adsorb and remove the impurities. ２ A method for purifying a fluoroolefin having the structure =CHF, comprising the steps of: the impure fluoroolefin is 1,1,3,3,3-pentafluoropropene; The solid adsorbent is activated alumina; method.

2. The method according to claim 1, wherein the total content of the impurities in the impurity-containing fluoroolefin is greater than 0 ppm and not more than 10 mass%.

3. 3. The method of claim 1 or 2, wherein the impurity-containing fluoroolefin is contacted with the solid adsorbent for a contact time of up to 60 minutes.

4. CF3, which contains at least one of haloalkane, haloalkene and haloalkyne impurities obtained by dehydrohalogenation reaction ２ or a method for producing a fluoroolefin having a =CHF structure with a purity of 99% or more, comprising the step of contacting the fluoroolefin having a =CHF structure with a solid adsorbent to adsorb and remove the impurities. ２ or a method for producing a fluoroolefin having the structure =CHF, the impure fluoroolefin is 1,1,3,3,3-pentafluoropropene; The solid adsorbent is activated alumina; method.

5. The method according to claim 4, wherein the total content of the impurities in the impurity-containing fluoroolefin is greater than 0 ppm and not more than 10 mass%.

6. 6. The method of claim 4 or 5, wherein the impurity-containing fluoroolefin is contacted with the solid adsorbent for a contact time of up to 60 minutes.

Images