High-purity 1,1-dichloro-3,3,3-trifluoropropene (HCFO-1223za), its production method and uses, and a method for preventing the acidification of HCFO-1223za

Abstract

To prevent the acidification of 1,1-dichloro-3,3,3-trifluoropropene (HCFO-1223za) and find a novel use of HCFO-1223za, and provide an acidification-free, high-purity HCFO-1223za and a method for producing the same.SOLUTION: The present invention provides a high-purity HCFO-1223za having a purity of 99.5% or more, with the concentration of acid halide impurities of 5 ppm or less, represented by the following formula (1): CX3CX2C(=O) X1 (where each X independently represents chlorine, fluorine or hydrogen, and X1 represents chlorine or fluorine), a method for producing the same, applications thereof and a method for preventing acidification of HCFO-1223za.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to high-purity 1,1-dichloro-3,3,3-trifluoropropene (hereinafter sometimes referred to as HCFO-1223za) and a method for producing the same, a method for preventing acidification of HCFO-1223za, and a novel use of the high-purity HCFO-1223za. [Background technology]

[0002] 1,1-Dichloro-3,3,3-trifluoropropene (HCFO-1223za) can be produced by contacting 1,1,1,3,3,3-hexachloropropane (boiling point 201°C) in the gas phase with hydrogen fluoride in the presence of a catalyst (Patent Document 1). HCFO-1223za has, for example, a melting point of -87°C and a boiling point of 55°C, so it can be expected to be used as a solvent. It has a high Kauri-butanol value (KB value), an index showing the solubility of oils and fats, of 46, and has excellent oil solubility, so it can be expected to be used as a cleaning agent. It also has a high specific gravity of 1.44g / mL, so it can be expected to be used for particle removal. In addition, it has no flash point and is non-flammable, so it is not subject to the Fire Service Act. It is a fluorine-based solvent, so it is highly volatile and can be easily dried. Since the specific heat is low at 0.95 kJ / kg K and the latent heat is low at 163 kJ / kg, distillation recovery can be performed with low energy. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 10-503518 Summary of the Invention [Problem to be solved by the invention]

[0004] In the stage of investigating new uses of HCFO-1223za, the present inventors discovered a phenomenon in which HCFO-1223za obtained by the above-mentioned manufacturing method becomes acidic when stored in the air. When a solvent that has become acidic is used to clean metals, it corrodes the metal and cannot be used. Therefore, the present inventors have found the need to prevent the acidification of HCFO-1223za in order to develop new uses of HCFO-1223za, particularly its use as a solvent. Therefore, the object of the present invention is to prevent the acidification of HCFO-1223za and to find new uses for HCFO-1223za. Another object of the present invention is to provide high-purity HCFO-1223za that does not become acidic and a manufacturing method thereof. [Means for solving the problem]

[0005] The present invention provides the following: [1] The following formula (1): CX3CX2C(=O)X 1 (1) (wherein each X is independently chlorine, fluorine or hydrogen; X 1 is chlorine or fluorine.) High-purity 1,1-dichloro-3,3,3-trifluoropropene having a purity of 99.5% or more and an acid halide impurity concentration of 5 ppm or less. [2] The high-purity 1,1-dichloro-3,3,3-trifluoropropene according to [1], wherein the acid halide impurity represented by formula (1) includes at least one selected from the group consisting of CHClFCF2C(=O)Cl and CF3CHClC(=O)Cl. [3] A method for producing high-purity 1,1-dichloro-3,3,3-trifluoropropene according to [1] or [2], characterized in that 1,1,1,3,3,3-hexachloropropane is reacted with hydrogen fluoride to obtain a reaction liquid containing 1,1-dichloro-3,3,3-trifluoropropene, the reaction liquid is distilled to obtain a purified product having a 1,1-dichloro-3,3,3-trifluoropropene concentration of 99.5% or more, and the purified product is contacted with a basic substance. [4] The method for producing high purity 1,1-dichloro-3,3,3-trifluoropropene according to [3], wherein the basic substance is selected from the group consisting of an aqueous solution of a metal hydroxide, an aqueous solution of a metal carbonate, and an aqueous solution of a metal bicarbonate. [5] The method for producing high purity 1,1-dichloro-3,3,3-trifluoropropene according to [4], characterized in that the purified product is contacted with a basic substance to obtain a mixed liquid, the mixed liquid is separated into an aqueous layer and an organic layer, and then the organic phase is separated. [6] The method for producing high-purity 1,1-dichloro-3,3,3-trifluoropropene according to [5], wherein the separated organic layer is washed with water having a resistivity of 0.1 MΩ·cm or more. [7] Use of the high-purity 1,1-dichloro-3,3,3-trifluoropropene according to [1] or [2] as a solvent. [8] Use of the high-purity 1,1-dichloro-3,3,3-trifluoropropene according to [1] or [2] as a cleaning agent for metal surfaces. [9] A method for cleaning a metal surface, comprising contacting the metal surface with the high-purity 1,1-dichloro-3,3,3-trifluoropropene according to [1] or [2].

[10] A method for preventing acidification of 1,1-dichloro-3,3,3-trifluoropropene (HCFO-1223za), comprising contacting HCFO-1223za with a basic substance. Effect of the Invention

[0006] According to the present invention, there is provided a high-purity HCFO-1223za and a method for producing the same. The high-purity HCFO-1223za of the present invention does not become acidic even when stored in the air, and is useful for various applications, particularly as a cleaning agent for metal surfaces. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] [Effect] The present inventors have conducted extensive research and found that the acidification of HCFO-1223za is caused by the hydrolysis of acid halides present as impurities by moisture in the air to produce hydrogen halide and carboxylic acid. Examples of such acid halides include those represented by the following formula (1): CX3CX2C(=O)X 1 (1) (wherein each X is independently chlorine, fluorine or hydrogen; X 1 is chlorine or fluorine.) The compound represented by the formula:

[0008] The inventors unexpectedly found that the acid halide impurities could be easily removed by washing HCFO-1223za with an alkaline aqueous solution, and that after the removal of the acid halide impurities, HCFO-1223za did not become acidic even after heating under reflux in air for 30 days.

[0009] [High purity HCFO-1223za] The high purity HCFO-1223za of the present invention is represented by the following formula (1): CX3CX2C(=O)X 1 (1) (wherein each X is independently chlorine, fluorine or hydrogen; X 1 is chlorine or fluorine) and the purity of HCFO-1223za is 99.5% or more, preferably 99.9% or more, and more preferably 99.99% or more. In this specification, unless otherwise specified, "%" and "ppm" are percentages by weight when the total weight is 100%. Examples of acid halide impurities of formula (1) include CHClFCF2C(=O)Cl and CF3CHClC(=O)Cl.

[0010] [Manufacturing method of high purity HCFO-1223za] The high purity HCFO-1223za of the present invention is (a) 1,1,1,3,3,3-hexachloropropane (hereinafter sometimes referred to as "HCP") is reacted with hydrogen fluoride (HF) to obtain a reaction solution containing 1,1-dichloro-3,3,3-trifluoropropene (HCFO-1223za), (b) distilling the reaction solution to obtain a purified product having a HCFO-1223za concentration of 99.5% or more, preferably 99.9% or more, and more preferably 99.99% or more; (c) contacting the purified product with a basic substance; The method is obtained by a method comprising the steps of:

[0011] Process (a): Step (a) can be a gas phase reaction or a liquid phase reaction. When the gas phase reaction is carried out at normal pressure, the boiling point of HCP is about 201°C, so liquid HCP is introduced into an evaporator heated to a temperature above this temperature, and the HCP is vaporized and reacted. When introducing liquid HCP into the evaporator, a spray nozzle can be used to atomize the liquid HCP and introduce it into the evaporator, which can increase the efficiency of vaporization.

[0012] In the gas phase reaction, gaseous HCP and HF can be continuously introduced into the reactor. The amount of HCP and HF introduced in the gas phase reaction is preferably 1:1 to 1:20, more preferably 1:1 to 1:10, and most preferably 1:1 to 1:5, in terms of molar ratio. When the gas phase reaction is carried out on a small scale, for example, HCP is flowed at a flow rate of 5 g / min to 50 g / min, and HF is flowed at a flow rate of 1 g / min to 15 g / min.

[0013] In the gas phase reaction, the temperature of the reactor is 100 to 400°C, preferably 200 to 400°C, more preferably 200 to 350°C, and most preferably 250 to 350°C.

[0014] Examples of catalysts for gas phase reactions include metal fluorides, such as alkali metal fluorides, alkaline earth metal fluorides, and transition metal fluorides, and these may be used in combination of two or more. Examples of alkali metal fluorides include lithium fluoride, sodium fluoride, and potassium fluoride. Examples of alkaline earth metal fluorides include magnesium fluoride, calcium fluoride, and barium fluoride. Examples of transition metal fluorides include chromium fluoride, molybdenum fluoride, antimony fluoride, niobium fluoride, manganese fluoride, iron fluoride, cobalt fluoride, copper fluoride, nickel fluoride, zinc fluoride, and silver fluoride. Examples of chromium fluoride include chromium (III) fluoride, chromium (VI) fluoride, and mixtures thereof. As the molybdenum fluoride, any of molybdenum fluoride (IV), molybdenum fluoride (V), molybdenum fluoride (VI) and mixtures thereof can be used. As the antimony fluoride, any of antimony fluoride (III), antimony fluoride (V) and mixtures thereof can be used. As the niobium fluoride, any of niobium fluoride (II), niobium fluoride (III), niobium fluoride (IV), niobium fluoride (V) and mixtures thereof can be used. As the manganese fluoride, any of manganese fluoride (II), manganese fluoride (III), manganese fluoride (IV) and mixtures thereof can be used. As the iron fluoride, any of iron fluoride (II), iron fluoride (III) and mixtures thereof can be used. As the cobalt fluoride, any of cobalt fluoride (II), cobalt fluoride (III) and mixtures thereof can be used. As copper fluoride, any of copper fluoride (I), copper fluoride (II), and mixtures thereof can be used. As for nickel fluoride and zinc fluoride, divalent metal fluorides exist stably. As for silver fluoride, any of silver fluoride (I), silver fluoride (II), silver fluoride (III), and mixtures thereof can be used.

[0015] In the present invention, the metal fluoride can be used by being supported on a carrier. Examples of the carrier include porous substances such as activated carbon, alumina, zeolite, and foam metal, and these may be used in combination of two or more. By supporting the metal fluoride on a carrier, the moldability of the metal fluoride support is improved, and the support can be formed into pellets (cylindrical) (e.g., particle size 0.5 to 30 mm), honeycomb, granular (spindle) (e.g., particle size 0.5 to 30 mm), spherical (e.g., particle size 0.5 to 30 mm), and other lumps other than powder, in addition to being used as a powder. By supporting the metal fluoride on a carrier, the handling is improved compared to using the metal fluoride as a powder. For example, there are advantages such as the problem of the reaction efficiency being reduced due to the solidification of the metal fluorides themselves forming a flow path for the raw material gas, and the sintering of the unreacted metal fluoride and the metal chloride by-product after the reaction is less likely to occur.

[0016] A preferred catalyst for the gas phase reaction is a chromium fluoride catalyst supported on activated carbon, such as CrF3 / C. For example, CrF3 / C can be prepared by filling a reactor with CrCl3 / C, flowing HF into the reactor, and performing halogen exchange with HF.

[0017] The reactor may be, for example, a cylindrical tube equipped with a heater for adjusting the reaction temperature, filled with metal fluorides of various shapes, and configured to allow a raw material gas to flow from one end of the tube to the other end. When the cylindrical tube loaded with metal fluorides is extended vertically, the raw material gas is preferably flowed uniformly from top to bottom little by little, since the raw material gas can be flowed little by little by utilizing gravity. When the cylindrical tube is extended vertically and the raw material gas is flowed from bottom to top, it is desirable in terms of reaction efficiency to place a pellet-like metal fluoride with a large particle size at the bottom of the cylindrical tube and a powder-like metal fluoride with a small particle size at the top of the cylindrical tube. Examples of materials for the reactor include corrosion-resistant metals such as stainless steel, Inconel, Monel, Hastelloy, and nickel. Among these, nickel is preferable in terms of corrosion resistance.

[0018] When performing a liquid phase reaction, the reaction vessel is filled with liquid HCP and liquid or gaseous HF is introduced. The reaction temperature and catalyst conditions for the liquid phase reaction can be the same as those for the gas phase reaction.

[0019] Step (b) can be carried out by a known distillation method, but in order to achieve a purity of 99.5% or more for HCFO-1223za, it is preferable to carry out a distillation of 5 or more stages, and in consideration of purity and energy efficiency, it is more preferable to carry out a distillation of 10 to 50 stages. If the concentration of HCFO-1223za is less than 99.5%, even if the product is treated by contacting it with a basic substance in the next step, the concentration of HCFO-1223za in the final product will be less than 99.5%, and therefore it cannot be used as a high-purity product, which is not desirable.

[0020] In step (c), the purified product obtained in step (b) is contacted with a basic substance. Since HCFO-1223za is liquid at room temperature and normal pressure (25°C, 1 atm) and insoluble in water, this step can be carried out, for example, by mixing the purified product with an aqueous solution of a basic substance, separating the organic layer containing HCFO-1223za and the aqueous layer containing the basic substance, and separating the organic layer. More preferably, the separated organic layer is washed with pure water (i.e., water having a resistivity of 0.1 MΩ·cm or more). By washing with pure water, the basic substance remaining in the organic layer can be significantly removed.

[0021] Examples of basic substances include aqueous solutions of metal hydroxides, aqueous solutions of metal carbonates, aqueous solutions of metal bicarbonates, and combinations thereof. Examples of metal hydroxides include hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, and hydroxides of alkaline earth metals such as barium hydroxide, magnesium hydroxide, and calcium hydroxide. Examples of metal carbonates include carbonates of alkali metals such as lithium carbonate, sodium carbonate, and potassium carbonate, and carbonates of alkaline earth metals such as barium carbonate, magnesium carbonate, and calcium carbonate. Examples of metal bicarbonates include bicarbonates of alkali metals such as lithium bicarbonate, sodium bicarbonate, and potassium bicarbonate, and bicarbonates of alkaline earth metals such as barium bicarbonate, magnesium bicarbonate, and calcium bicarbonate.

[0022] Since the concentration of impurities in the purified product to be washed is low, the concentration of the aqueous solution of the basic substance is preferably 0.1 to 20%, more preferably 0.3 to 10%, even more preferably 0.5 to 7%, and most preferably 1 to 5%.

[0023] [Uses of the high-purity HCFO-1223za of the present invention] The high purity HCFO-1223za of the present invention has two chlorine atoms, and therefore has excellent solubility in organic matter, especially oil. Taking advantage of this property, it is useful for the following applications:

[0024] (1) Use as a solvent and cleaning agent The high purity HCFO-1223za of the present invention can be mixed in any ratio with organic solvents such as ketones such as acetone and acetophenone, nitriles such as acetonitrile and propionitrile, ethers such as diisopropyl ether, t-butyl methyl ether, tetrahydrofuran, diglyme, and 1,4-dioxane, sulfoxides such as dimethyl sulfoxide and sulfolane, amides such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone, hydrocarbons such as hexane, heptane, cyclohexane, benzene, and toluene, and alcohols such as methanol, ethanol, and isopropanol. Therefore, it can be used in a wide range of applications as a mixed solvent. In addition, the high purity HCFO-1223za of the present invention is particularly excellent in solubility of oil, and can be suitably used as a cleaning agent. The boiling point of the high purity HCFO-1223za of the present invention is 55°C. Therefore, it can be easily volatilized and removed. The high purity HCFO-1223za of the present invention does not become acidic even when heated under reflux in the air for 30 days. Therefore, it is particularly suitable for cleaning metal surfaces where corrosion by acid is a problem. Since metal surfaces are affected not only by acids but also by alkalis, it is more preferable to use high-purity HCFO-1223za, which has been washed with pure water to remove residual basic substances, for cleaning metal surfaces.

[0025] (2) Use as a foaming agent The high purity HCFO-1223za of the present invention can be used to prepare foamable compositions of thermosetting resins such as polyurethane and thermoplastic resins such as polystyrene, polyethylene, and polypropylene, taking advantage of its ability to dissolve organic matter.

[0026] [How to prevent acidification of HCFO-1223za] The high purity HCFO-1223za of the present invention does not become acidic even when heated under reflux in the atmosphere for 30 days. As described above, by contacting HCFO-1223za with a basic substance, acid halides that cause acidification are removed. EXAMPLES

[0027] The present invention will be described in detail with reference to the following examples, but the scope of the present invention should not be construed as being limited to these examples. In the following examples, unless otherwise specified, % indicates a ratio with the whole being 100% by weight. Furthermore, "pure water" means water having a resistivity of 0.1 MΩ cm or more obtained by a purification procedure such as distillation.

[0028] (Reference example: Preparation of HCFO-1223za sample) 1,1,1,3,3,3-Hexachloropropane vaporized in an evaporator heated to 300°C was continuously introduced into a cylindrical reactor at 14 g / min, and anhydrous hydrogen fluoride was continuously introduced into the cylindrical reactor at 4 g / min. The reactor was pre-filled with a chromium fluoride catalyst supported on activated carbon. The outlet gas from the reactor heated to 200°C was introduced into a collection tank filled with 30 kg of ice water for 24 hours. The liquid in the collection tank was separated into layers, yielding 12.6 kg of organic matter. This organic matter was purified by distillation to obtain HCFO-1223za with the following composition.

[0029] [Table 1]

[0030] The acid halide impurities were identified using gas chromatography-mass spectrometry (GC-MS) with the EI (electron ionization) and PI (photoionization) methods. From the fragments obtained from GC-MS, the acid halide impurities were identified as CHClFCF2C(=O)Cl and CF3CHClC(=O)Cl. The fact that the acid halide impurities have an acid chloride structure was also confirmed by the low electron ionization (LEI) method.

[0031] Example 1 10mL of the HCFO-1223za sample prepared above and 5mL of 1% NaOH aqueous solution were placed in a glass vial, capped, and shaken 50 times. After leaving it to stand for 10 minutes to separate, only the organic layer was separated. This organic layer was sealed in a glass vial and left to stand under heating at 55℃, and the pH was checked after 2 and 7 days. As a result, it remained neutral even after 7 days.

[0032] Example 2 10mL of the HCFO-1223za sample prepared above and 5mL of 1% KOH aqueous solution were placed in a glass vial, capped, and shaken 50 times. After leaving it to stand for 10 minutes to separate, only the organic layer was separated. This organic layer was sealed in a glass vial and left to stand under heating at 55℃, and the pH was checked after 2 and 7 days. As a result, it remained neutral even after 7 days.

[0033] Example 3 10mL of the HCFO-1223za sample prepared above and 5mL of 4% NaHCO3 aqueous solution were placed in a glass vial, capped, and shaken 50 times. After leaving it to stand for 10 minutes to separate, only the organic layer was separated. This organic layer was sealed in a glass vial and left to stand under heating at 55℃, and the pH was checked after 2 and 7 days. As a result, it remained neutral even after 7 days.

[0034] Example 4 10mL of the HCFO-1223za sample prepared above and 5mL of 4% Na2CO3 aqueous solution were placed in a glass vial, capped, and shaken 50 times. After leaving it to stand for 10 minutes to separate, only the organic layer was separated. This organic layer was sealed in a glass vial and left to stand under heating at 55℃, and the pH was checked after 2 and 7 days. As a result, it remained neutral even after 7 days.

[0035] Comparative Example 1 10 mL of the HCFO-1223za sample prepared above was sealed in a glass vial and heated to 55°C, and the pH was checked after 2 and 7 days. As a result, the pH remained unchanged at 4 after both 2 and 7 days.

[0036] Comparative Example 2 10mL of the HCFO-1223za sample prepared above and 5mL of pure water were placed in a glass vial, the vial was capped and shaken 50 times. After leaving it to stand for 10 minutes to separate, only the organic layer was separated. This organic layer was sealed in a glass vial and left to stand at 55℃ under heating, and the pH was checked after 2 and 7 days. As a result, the pH changed to 6 after 2 days and to 5 after 7 days.

[0037] The results of Comparative Examples 1-2 and Examples 1-4 are shown in Table 2. [Table 2]

[0038] From the results of Comparative Examples 1 and 2, when the HCFO-1223za sample was not washed with an aqueous basic substance solution, the acid halide concentration in the sample at 0 days was 7 ppm (Comparative Example 1) and 6 ppm (Comparative Example 2), indicating that acidification occurs over time. In Examples 1 to 4 in which the HCFO-1223za sample was washed with an aqueous basic substance solution, no acid halide was detected at 0 days, and no acid halide was detected thereafter. In order to prevent acidification of HCFO-1223za, it is considered necessary that the acid halide concentration at 0 days is 5 ppm or less.

[0039] (Example 5: Durability test) 100mL of 4% Na2CO3 aqueous solution was added to 300mL of the HCFO-1223za sample prepared above, and the mixture was shaken 50 times using a separatory funnel and left to stand for 10 minutes. The organic layer (lower layer) was separated, and 100mL of pure water was added to this organic layer (about 300mL), and the mixture was shaken 50 times using a separatory funnel and left to stand for 10 minutes. The organic layer obtained by the separation was then used for the test. 75g of the HCFO-1223za sample washed with 4% Na2CO3 aqueous solution and pure water as described above was weighed into a 100mL eggplant flask. A Dimroth condenser (circulating refrigerant temperature: -10℃) was attached to the flask, and the top was left open without nitrogen sealing or the like. The flask was immersed in an oil bath set to 65℃, and the heating reflux test was started. When analyzing, each flask was raised from the oil bath and cooled sufficiently, and GC analysis and pH check were performed. After that, about 2 g of the organic layer was sampled and washed with 10 mL of pure water. 5 mL of this pure water layer was taken and titrated with 0.001 M NaOH aqueous solution to determine the acid content. As a result, even after 30 days of continuous heating, the pH remained at 7 and the acid content remained at 0.0 ppm. The results are shown in Table 3.

[0040] [Table 3]

[0041] Table 3 shows that even after 30 days, no acid content (ppm concentration of HCl) was detected by titration, and the concentration of HCFO-1223za was maintained at a high purity of 99.99 or more.

[0042] [Cleaning power evaluation test] The solubility (cleaning ability) of each evaluation target in the high purity HCFO-1223za of the present invention is shown in the table below. [Table 4] *1: Reference material: Development of cleaning technology, CMC Publishing *2: CELEFIN(registered trademark) 1233Z, AMOLEA(registered trademark) AS-300, Asahiclean(registered trademark) AK-225, Zeorora(registered trademark) HTA, and Asahiclean(registered trademark) AE-3000 are all product names of cleaning agents.

[0043] As can be seen from the above table, the high purity HCFO-1223za of the present invention is completely miscible with any processing oil at a weight ratio of 1:1, and therefore has excellent oil solubility.

[0044] [Metal surface cleaning test] The high purity HCFO-1223za of the present invention is suitable for cleaning metal surfaces because it does not become acidic. To evaluate this, the following test was carried out. Experimental method: An iron test piece (dimensions: 10 mm x 10 mm x 1 mm) was placed in a glass vial, 10 g of HCFO-1223za was added, and the vial was stored at 55°C for 4 days. The following HCFO-1223za was used: Acidic HCFO-1223za: Reference HCFO-1223za sample with pH=4 before alkaline cleaning. GC purity 99.993%. Contains 6ppm acid halide. High purity HCFO-1223za: Alkaline washed and purified water washed, pH=7. GC purity 99.995%. Contains no acid halide impurities. The test results are shown in the table below. [Table 5]

[0045] As can be seen from the above table, the test piece that came into contact with the acidic HCFO-1223za developed reddish-brown rust on its surface after 4 days (see the stain on the lower right part of the test piece after the test). On the other hand, the test piece that came into contact with the high-purity HCFO-1223za of the present invention did not change on its surface even after 4 days, maintained its metallic luster, and did not develop rust. Thus, the high-purity HCFO-1223za of the present invention is not only excellent in cleaning organic matter such as oil on metal surfaces, but is also excellent in that it is less likely to develop rust on the metal surface after cleaning. The high-purity HCFO-1223za of the present invention can provide a cleaning agent that is particularly suitable for cleaning metal surfaces.

Claims

1. The method comprises reacting 1,1,1,3,3,3-hexachloropropane with hydrogen fluoride to obtain a reaction liquid containing 1,1-dichloro-3,3,3-trifluoropropene, distilling the reaction liquid to obtain a purified product having a 1,1-dichloro-3,3,3-trifluoropropene concentration of 99.5% or more, and contacting the purified product with a basic substance. The following formula (1): CX 3 CX 2 C(=O)X 1 (1) (wherein each X is independently chlorine, fluorine or hydrogen, and X 1 is chlorine or fluorine.) The present invention relates to a method for producing high-purity 1,1-dichloro-3,3,3-trifluoropropene having a purity of 99.5% or more and in which the concentration of an acid halide impurity represented by the following formula is 5 ppm or less.

2. The method for producing high purity 1,1-dichloro-3,3,3-trifluoropropene according to claim 1, wherein the acid halide impurity represented by formula (1) includes at least one selected from the group consisting of CHClFCF 2 C(═O)Cl and CF 3 CHClC(═O)Cl.

3. 3. The method for producing high purity 1,1-dichloro-3,3,3-trifluoropropene according to claim 1, wherein the basic substance is selected from the group consisting of an aqueous solution of a metal hydroxide, an aqueous solution of a metal carbonate, and an aqueous solution of a metal bicarbonate.

4. The method for producing high purity 1,1-dichloro-3,3,3-trifluoropropene according to claim 3, characterized in that the purified product is contacted with a basic substance to obtain a mixed liquid, the mixed liquid is separated into an aqueous layer and an organic layer, and the organic phase is separated.

5. The method for producing high-purity 1,1-dichloro-3,3,3-trifluoropropene according to claim 4, wherein the separated organic layer is washed with water having a resistance value of 0.1 MΩ·cm or more.

6. 1,1,1,3,3,3-hexachloropropane is reacted with hydrogen fluoride to obtain a reaction liquid containing 1,1-dichloro-3,3,3-trifluoropropene; The reaction solution is distilled to obtain a purified product having a 1,1-dichloro-3,3,3-trifluoropropene concentration of 99.5% or more; The purified product is contacted with a basic substance to produce a compound represented by the following formula (1): CX 3 CX 2 C(=O)X 1 (1) (wherein each X is independently chlorine, fluorine or hydrogen, and X 1 is chlorine or fluorine.) and producing high-purity 1,1-dichloro-3,3,3-trifluoropropene having a purity of 99.5% or more and an acid halide impurity concentration of 5 ppm or less, The high purity 1,1-dichloro-3,3,3-trifluoropropene is used as a solvent.

7. 1,1,1,3,3,3-hexachloropropane is reacted with hydrogen fluoride to obtain a reaction liquid containing 1,1-dichloro-3,3,3-trifluoropropene; The reaction solution is distilled to obtain a purified product having a 1,1-dichloro-3,3,3-trifluoropropene concentration of 99.5% or more; The purified product is contacted with a basic substance to produce a compound represented by the following formula (1): CX 3 CX 2 C(=O)X 1 (1) (wherein each X is independently chlorine, fluorine or hydrogen, and X 1 is chlorine or fluorine.) and producing high-purity 1,1-dichloro-3,3,3-trifluoropropene having a purity of 99.5% or more and an acid halide impurity concentration of 5 ppm or less, The high purity 1,1-dichloro-3,3,3-trifluoropropene is used as a cleaning agent for metal surfaces.

8. 1,1,1,3,3,3-hexachloropropane is reacted with hydrogen fluoride to obtain a reaction liquid containing 1,1-dichloro-3,3,3-trifluoropropene; The reaction solution is distilled to obtain a purified product having a 1,1-dichloro-3,3,3-trifluoropropene concentration of 99.5% or more; The purified product is contacted with a basic substance to produce a compound represented by the following formula (1): CX 3 CX 2 C(=O)X 1 (1) (wherein each X is independently chlorine, fluorine or hydrogen, and X 1 is chlorine or fluorine.) and producing high-purity 1,1-dichloro-3,3,3-trifluoropropene having a purity of 99.5% or more and an acid halide impurity concentration of 5 ppm or less, A method for cleaning a metal surface comprising contacting the metal surface with the high purity 1,1-dichloro-3,3,3-trifluoropropene.

9. The method according to claim 6, wherein the acid halide impurity represented by formula (1) comprises at least one selected from the group consisting of CHClFCF 2 C(═O)Cl and CF 3 CHClC(═O)Cl.

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