Method for producing 1-chloro-2,3,3-trifluoropropene

Abstract

Provided is a method that is for producing 1-chloro-2,3,3-trifluoropropene, that can reduce the amount of propyne generated, and that provides an excellent conversion rate of 3-chloro-1,1,2,2-tetrafluoropropane as a raw material.　The method for producing 1-chloro-2,3,3-trifluoropropene according to the present invention involves dehydrofluorinating 3-chloro-1,1,2,2-tetrafluoropropane in the presence of a phase transfer catalysis, an organic solvent having a dielectric constant of 30 or more, and a base.

Description

[Technical field]

[0001] The present invention relates to a process for producing 1-chloro-2,3,3-trifluoropropene. [Background technology]

[0002] 1-Chloro-2,3,3-trifluoropropene (CHCl=CF-CHF2, HCFO-1233yd, hereafter also referred to as 1233yd) is a compound used as a new cleaning agent, refrigerant, blowing agent, solvent, and aerosol application with a low global warming potential (GWP) as a replacement for 3,3-dichloro-1,1,1,2,2-pentafluoropropane (CF3-CF2-CHCl2, hereafter also referred to as HCFC-225ca) and 1,3-dichloro-1,1,2,2,3-pentafluoropropane (CClF2-CF2-CClFH, hereafter also referred to as HCFC-225cb). Patent Document 1 discloses a method for producing 1233yd by subjecting 3-chloro-1,1,2,2-tetrafluoropropane (CHF2-CF2-CH2Cl, HCFC-244ca, hereinafter also referred to as 244ca) to a dehydrofluorination reaction in the presence of a base. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-164152 A Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, in order to increase the yield of 1233yd, there has been a demand to improve the conversion rate of 244ca, which is the raw material for 1233yd. The present inventors produced 1233yd by the method described in Patent Document 1, and found that although the conversion rate of 244ca was high, there was a problem in that the amount of the by-product, 1-chloro-3,3-difluoropropyne (hereinafter also simply referred to as propyne), could not be sufficiently reduced.

[0005] The present invention aims to provide a method for producing 1233yd, which can reduce the amount of propyne produced and has an excellent conversion rate of the raw material 244ca. [Means for solving the problem]

[0006] As a result of investigations aimed at solving the above-mentioned problems, the inventors discovered that the desired effects can be obtained by carrying out the dehydrofluorination reaction of 244ca in the presence of a phase transfer catalyst, an organic solvent having a dielectric constant of 30 or more, and a base, and thus arrived at the present invention.

[0007] That is, the present inventors have found that the above problems can be solved by the following configuration. [1] A method for producing 1-chloro-2,3,3-trifluoropropene, comprising dehydrofluorinating 3-chloro-1,1,2,2-tetrafluoropropane in the presence of a phase transfer catalyst, an organic solvent having a dielectric constant of 30 or more, and a base. [2] The method for producing 1-chloro-2,3,3-trifluoropropene according to [1], wherein a mass ratio of an amount of the phase transfer catalyst to an amount of the organic solvent is 0.020 to 0.20. [3] The method for producing 1-chloro-2,3,3-trifluoropropene according to [1] or [2], wherein a mass ratio of an amount of the phase transfer catalyst to an amount of the organic solvent is 0.020 to 0.090. [4] The dehydrofluorination reaction is further carried out in the presence of water; The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to [3], wherein a mass ratio of the amount of the organic solvent used to the amount of the water used is 0.01 to 0.50. [5] The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to [4], wherein the organic solvent is at least one selected from the group consisting of dimethyl sulfoxide, acetonitrile and nitromethane. [6] The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to [5], wherein the organic solvent is at least one of dimethyl sulfoxide and acetonitrile. [7] The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to [6], wherein the phase transfer catalyst is a quaternary ammonium salt. [8] The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to [7], wherein the base is at least one of potassium hydroxide and sodium hydroxide. [9] The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to [8], wherein the reaction temperature in the dehydrofluorination reaction is 40 to 90°C.

[10] The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to [9], which is carried out as a liquid phase reaction and uses water as a solvent.

[11] The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to

[10] , wherein the dehydrofluorination reaction is further carried out in the presence of water, and the dehydrofluorination reaction proceeds at an interface between an aqueous phase containing a base and an organic phase containing 3-chloro-1,1,2,2-tetrafluoropropane.

[12] The base is used in the form of a base solution, and the amount of the solvent used in the base solution is 98 to 300 parts by mass relative to the amount of 3-chloro-1,1,2,2-tetrafluoropropane used (100 parts by mass); The amount of the phase transfer catalyst used is 0.1 to 3 parts by mass relative to the amount (100 parts by mass) of 3-chloro-1,1,2,2-tetrafluoropropane used, The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to

[11] , wherein the amount of the organic solvent used is 1 to 30 parts by mass relative to the amount (100 parts by mass) of 3-chloro-1,1,2,2-tetrafluoropropane used.

[13] A method for producing 1-chloro-2,3,3-trifluoropropene, comprising recovering the organic solvent from a reaction solution containing the 1-chloro-2,3,3-trifluoropropene produced by the method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to

[12] and the organic solvent, and dehydrofluorinating 3-chloro-1,1,2,2-tetrafluoropropane in the presence of the recovered organic solvent, a phase transfer catalyst, and a base.

[14] A method for producing 1-chloro-2,3,3-trifluoropropene, comprising obtaining a reaction liquid containing 1-chloro-2,3,3-trifluoropropene by the method for producing 1-chloro-2,3,3-trifluoropropene according to any one of [1] to

[13] , and separating 1-chloro-2,3,3-trifluoropropene from the reaction liquid.

[15] The method for producing 1-chloro-2,3,3-trifluoropropene according to

[14] , wherein the method for separating 1-chloro-2,3,3-trifluoropropene from the reaction solution is at least one method selected from the group consisting of a separation and purification method, a water washing treatment, and a solid adsorption treatment.

[16] The method for producing 1-chloro-2,3,3-trifluoropropene according to

[15] , wherein the solid adsorption treatment is carried out with at least one material selected from the group consisting of activated carbon, zeolite, silica and alumina. Effect of the Invention

[0008] According to the present invention, a method for producing 1233yd can be provided that can reduce the amount of propyne produced and has an excellent conversion rate of the raw material 244ca. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The terms used in the present invention have the following meanings. A numerical range expressed using "~" means that the range includes the numerical values ​​before and after "~" as the lower and upper limits. In this specification, for halogenated hydrocarbons, the abbreviation for the compound is written in parentheses after the compound name, but in this specification, the abbreviation will be used instead of the compound name as necessary. 1233yd has two geometric isomers, Z and E, depending on the position of the substituent on the double bond. In this specification, unless otherwise specified, when a compound name or abbreviation of a compound is used, it indicates at least one selected from Z and E, and when a compound name or abbreviation of a compound is followed by (E) or (Z), it indicates that the compound is the (E) or (Z) form. For example, HCFO-1233yd(Z) indicates the Z form, and HCFO-1233yd(E) indicates the E form. The "amount of A used" refers to the total amount of A added to the reactor for use in the production of 1233yd. "A" is a component used in the reaction, and examples of this include 244ca, a phase transfer catalyst, an organic solvent with a dielectric constant of 30 or more, a base, and a solvent, which will be described later.

[0010] [1233yd manufacturing method] The method for producing 1233yd of the present invention is characterized by dehydrofluorinating 244ca in the presence of a phase transfer catalyst, an organic solvent having a dielectric constant of 30 or more (hereinafter also referred to as a specific organic solvent), and a base. The dehydrofluorination reaction of 244ca in the production method of the present invention is a reaction represented by the following formula 1.

[0011] [ka]

[0012] According to the production method of the present invention, the amount of propyne produced can be reduced and the conversion rate of the raw material 244ca is excellent. Although the details of the reason for this are not clear, it is presumed to be due to the following reasons. In the production of 1233yd using 244ca, propyne (e.g., 1-chloro-3,3-difluoropropyne) is generated when the target product 1233yd is dehydrofluorinated. The inventors speculate that the use of a phase transfer catalyst and a specific organic solvent in combination improves the reaction rate of 244ca, shortens the reaction time, and shortens the period during which the generated 1233yd exists in the reaction system, thereby suppressing the dehydrofluorination reaction of 1233yd. In addition, it is speculated that the combined use of a phase transfer catalyst and a specific organic solvent promoted the dehydrofluorination reaction of 244ca, thereby improving the conversion rate of 244ca. In the following description, the excellent effect of the present invention means that the conversion rate of 244ca is excellent and that the amount of propyne produced can be reduced.

[0013] <244ca> 244ca is a compound known as a raw material or intermediate for the production of fluorine-containing compounds. For example, 244ca can be produced by chlorinating 2,2,3,3-tetrafluoropropanol (TFPO) with thionyl chloride (SOCl2) in the presence of N,N-dimethylformamide (DMF), as shown in the following formula 2. This process can be carried out in the liquid phase or the gas phase.

[0014] [ka]

[0015] In the reaction of formula 2, the reactor may be a general reactor such as a glass flask, a SUS autoclave, a glass-lined reactor, etc. When using a glass flask, it is preferable to install a glass distillation column filled with Raschig rings and simultaneously produce and separate 244ca.

[0016] The amount of DMF to be added per mole of TFPO is preferably 0.001 to 0.2 moles, and the amount of thionyl chloride to be added is preferably about 0.5 to 1.5 moles. DMF acts as a catalyst to promote the reaction. The reaction of formula 2 proceeds quantitatively with equimolar amounts, so there is no need for either of them to be in excess.

[0017] If the rate of addition of thionyl chloride per mole of TFPO is too fast, the rate of hydrogen chloride production will increase, and the product may be discharged together with hydrogen chloride to the outside of the system, resulting in loss. Therefore, it is preferable to drop thionyl chloride at a rate that keeps the temperature fluctuation due to the progress of the reaction within 30°C. If water is present, thionyl chloride reacts with water and is hydrolyzed to decompose into SO2 and HCl. Furthermore, 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane is also hydrolyzed and decomposed into TFPO, SO2, and HCl. To prevent this, it is preferable to replace the atmosphere in the reactor with dry nitrogen gas.

[0018] In the reaction of formula 2, thionyl chloride is added to react with TFPO to produce 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane. When 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane is heated, it undergoes a sulfur dioxide removal reaction to produce 244ca. The heating temperature is preferably 70 to 150°C, and more preferably 90 to 130°C. The heating rate is arbitrary, but in order to avoid insufficient treatment of the generated sulfur dioxide and insufficient recovery of the generated 244ca, it is desirable to adjust the generation rate by raising the temperature at a slow rate of about 1 to 2°C / min.

[0019] In the case where it is difficult to adjust the heating rate in heating 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane, it is preferable to adopt, for example, a method of heating 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane in a solvent (liquid phase reaction). The solvent has a boiling point higher than the reaction temperature of the decomposition reaction of 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane, and is less likely to react with the compound involved in the reaction represented by formula 2, and it is preferable to use an aprotic solvent. Specific examples include dimethyl sulfoxide and DMF. The amount of the solvent used is preferably 0.5 to 3 moles per mole of 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane.

[0020] The desulfurization reaction of 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane is preferably carried out as a liquid phase reaction by preparing a reactor similar to that described above. That is, a solvent is added to the reactor and heated to a temperature at which the desulfurization reaction can be carried out, and then 3-chlorosulfinyloxy-1,1,2,2-tetrafluoropropane is added dropwise to produce 244ca. The reaction temperature for the desulfurization reaction is preferably 70 to 150°C, and particularly preferably 90 to 130°C. The atmosphere in the reactor is preferably replaced with dry nitrogen gas.

[0021] The crude product of 244ca produced through the reaction of formula 2 is usually gaseous. This crude product is treated to remove hydrochloric acid and sulfur dioxide by a method such as washing with water, and impurities are removed by drying with a desiccant such as calcium chloride or a molecular sieve, and a composition containing 244ca can be recovered by a method such as cold trap. The obtained composition containing 244ca can be used in the production method of the present invention as it is or after further purification, for example, as a composition of 244ca with a purity of 99.5 mass% or more.

[0022] The 244ca used in the production method of the present invention may be 244ca with a purity of 100%, or a composition of high-purity 244ca that has been subjected to a purification process, or a composition containing 244ca and components other than 244ca (e.g., impurities, etc.). However, when using the latter composition, if the impurities are active in the reaction of the present invention, it is preferable to remove them in advance. For example, when producing 244ca by the method of scheme 2, if TFPO remains together with the produced 244ca, it may react with 1233yd, which is the product of the present invention, so when using the method of the present invention, it is preferable to remove TFPO as much as possible from the product.

[0023] In the production method of the present invention, 244ca obtained by a production method other than the above may also be used. Other specific examples of methods for producing 244ca include a method of reacting 1,1,2,2,3-pentafluoropropane (hereinafter also referred to as 245ca) with a chlorine-containing compound having 1 or 2 carbon atoms (preferably carbon tetrachloride, chloroform, dichloromethane, trichloroethylene, or tetrachloroethylene) in the presence of a catalyst containing a compound having at least one selected from Cr and Al, and a method of reacting 1,1,2,2,3-pentafluoropropane (245ca) with hydrogen chloride in the presence of a catalyst (preferably a metal catalyst).

[0024] <base> The base is not particularly limited as long as it is a base capable of carrying out a dehydrofluorination reaction. From the viewpoints of availability, reaction time and reaction yield, the base preferably contains at least one base selected from the group consisting of metal hydroxides, metal oxides and metal carbonates. The base may be used alone or in combination of two or more.

[0025] Examples of metal hydroxides include alkaline earth metal hydroxides and alkali metal hydroxides. Specific examples of alkaline earth metal hydroxides include magnesium hydroxide, calcium hydroxide, strontium hydroxide, and barium hydroxide. Specific examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, and potassium hydroxide.

[0026] Specific examples of metals constituting the metal oxide include alkali metal elements, alkaline earth metal elements, transition metal elements, and metal elements in Group 12 and Group 13 of the periodic table. Among these, alkali metal elements, alkaline earth metal elements, and metal elements in Groups 6, 8, 10, 12, and 13 of the periodic table are preferred, with sodium, calcium, chromium, iron, zinc, and aluminum being particularly preferred. The metal oxide may be an oxide containing one kind of metal, or a composite oxide containing two or more kinds of metals. As the metal oxide, sodium oxide, calcium oxide, chromium oxide (chromia), aluminum oxide (alumina) and zinc oxide are preferred from the viewpoints of reaction time and reaction yield, with alumina and chromia being particularly preferred.

[0027] Examples of metal carbonates include alkaline earth metal carbonates and alkali metal carbonates. Specific examples of alkaline earth metal carbonates include carbonates of metals such as beryllium, magnesium, calcium, strontium, barium, and radium. Specific examples of alkali metal carbonates include carbonates of metals such as lithium, sodium, potassium, rubidium, cesium, and francium.

[0028] Among them, the base is preferably a metal hydroxide from the viewpoint of reaction time and reaction yield, and at least one of potassium hydroxide and sodium hydroxide is particularly preferable. The metal hydroxide may be used alone or in combination of two or more kinds.

[0029] In the production method of the present invention, the base is preferably used in the form of a solution in which the base is dissolved in a solvent. The solvent is not particularly limited as long as it can dissolve a predetermined amount of base and does not contribute to the dehydrofluorination reaction. As the solvent, water is preferred from the viewpoints of being able to sufficiently dissolve an alkali metal hydroxide and being free of side reactions derived from the solvent. From the viewpoint of being able to increase the base concentration, the base is preferably a compound that dissolves in an amount of 1 g or more in 1 L of water, more preferably a compound that dissolves in an amount of 100 g or more, and particularly preferably a compound that dissolves in an amount of 200 g or more. In the following description, a solution in which a base is dissolved in a solvent is referred to as a "base solution", and when the solvent is water, it is referred to as an "aqueous base solution".

[0030] <Phase transfer catalyst> Examples of the phase transfer catalyst include quaternary ammonium salts, quaternary phosphonium salts, quaternary arsonium salts, sulfonium salts, crown ethers, etc., and quaternary ammonium salts are preferred in terms of obtaining superior effects of the present invention. The phase transfer catalyst may be used alone or in combination of two or more kinds.

[0031] The quaternary ammonium salt includes the compound represented by the following formula i.

[0032] [ka]

[0033] In formula i, R 11 ~R 14 each independently represents a monovalent hydrocarbon group or a monovalent hydrocarbon group having a functional group bonded thereto that is inert to the reaction; Y 1- represents an anion.

[0034] R 11 ~R 14 Examples of the hydrocarbon group in include an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, and an aryl group, and the alkyl group and the aryl group are preferred. R 11 ~R 14The number of carbon atoms in R is preferably 4 to 100. 11 ~R 14 may be the same or different from each other. R 11 ~R 14 However, when the functional group is a monovalent hydrocarbon group having a functional group that is inert to the reaction bonded thereto, the functional group is appropriately selected depending on the reaction conditions, and examples of the functional group include a halogen atom, an alkoxycarbonyl group, an acyloxy group, a nitrile group, an acyl group, a carboxy group, and an alkoxy group.

[0035] R 11 R 12 R 13 R 14 N + Specific examples of the ammonium salt include tetramethylammonium, tetraethylammonium, tetra-n-propylammonium, tetra-n-butylammonium, methyltri-n-octylammonium, cetyltrimethylammonium, benzyltrimethylammonium, benzyltriethylammonium, cetylbenzyldimethylammonium, cetylpyridinium, n-dodecylpyridinium, phenyltrimethylammonium, phenyltriethylammonium, N-benzylpicolinium, pentamethonium, and hexamethonium.

[0036] Y 1- Specific examples of the ion include a chloride ion, a fluorine ion, a bromide ion, an iodide ion, a sulfate ion, a nitrate ion, a phosphate ion, a perchlorate ion, a hydrogen sulfate ion, a hydroxide ion, an acetate ion, a benzoate ion, a benzenesulfonate ion, and a p-toluenesulfonate ion, and the chloride ion, the bromide ion, the iodide ion, the hydrogen sulfate ion, and the hydroxide ion are preferred.

[0037] From the viewpoint of versatility and reactivity, the compound represented by formula i is 11 R 12 R 13 R 14 N + And the following Y 1- The combination with is preferred. R 11 R 12R 13 R 14 N + : Tetramethylammonium, tetraethylammonium, tetra-n-propylammonium, tetra-n-butylammonium, methyltri-n-octylammonium. Y 1- : Fluorine ion, chloride ion, bromide ion, iodine ion, hydroxide ion.

[0038] As the quaternary ammonium salt, tetra-n-butylammonium chloride (TBAC), tetra-n-butylammonium bromide (TBAB) and methyltri-n-octylammonium chloride (TOMAC) are preferred in terms of providing better effects for the present invention.

[0039] The quaternary phosphonium salt includes a compound represented by the following formula ii.

[0040] [ka]

[0041] In formula ii, R 21 ~R 24 each independently represents a monovalent hydrocarbon group; Y 2- represents an anion.

[0042] R 21 ~R 24 Examples of the hydrocarbon group in include an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, and an aryl group, and the alkyl group and the aryl group are preferred.

[0043] Quaternary phosphonium (R 21 R 22 R 23 R 24 P +Specific examples of the above include tetraethylphosphonium, tetra-n-butylphosphonium, ethyltri-n-octylphosphonium, cetyltriethylphosphonium, cetyltri-n-butylphosphonium, n-butyltriphenylphosphonium, n-amyltriphenylphosphonium, methyltriphenylphosphonium, benzyltriphenylphosphonium, and tetraphenylphosphonium.

[0044] Y in formula ii 2- Specific examples of the ion include chloride ion, fluorine ion, bromine ion, iodine ion, sulfate ion, nitrate ion, phosphate ion, perchlorate ion, hydrogen sulfate ion, hydroxide ion, acetate ion, benzoate ion, benzenesulfonate ion, and p-toluenesulfonate ion, and the like are preferably the fluorine ion, chloride ion, and bromine ion.

[0045] The quaternary arsonium salt includes the compound represented by the following formula iii.

[0046] [ka]

[0047] In formula iii, R 31 ~R 34 each independently represents a monovalent hydrocarbon group; Y 3- represents an anion.

[0048] R 31 ~R 34 Specific examples of the hydrocarbon group in include an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, and an aryl group, and particularly, an alkyl group and an aryl group.

[0049] Y in formula iii 3- is preferably a halogen ion, and particularly preferably a fluorine ion, a chlorine ion, or a bromine ion.

[0050] Specific examples of the quaternary arsonium salt include triphenylmethylarsonium fluoride, tetraphenylarsonium fluoride, triphenylmethylarsonium chloride, tetraphenylarsonium chloride, and tetraphenylarsonium bromide, with triphenylmethylarsonium chloride being preferred.

[0051] The sulfonium salt includes a compound represented by the following formula iv.

[0052] [ka]

[0053] In formula iv, R 41 ~R 43 each independently represents a monovalent hydrocarbon group; Y 4- represents an anion.

[0054] R 41 ~R 43 Examples of the hydrocarbon group in include an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, and an aryl group, and the alkyl group and the aryl group are preferred.

[0055] Y in formula iv 4- As the cation, a halogen ion is preferred, and a fluorine ion, a chlorine ion, and a bromine ion are particularly preferred.

[0056] Specific examples of sulfonium salts include di-n-butylmethylsulfonium iodide, tri-n-butylsulfonium tetrafluoroborate, dihexylmethylsulfonium iodide, dicyclohexylmethylsulfonium iodide, dodecylmethylethylsulfonium chloride, and tris(diethylamino)sulfonium difluorotrimethylsilicate, with dodecylmethylethylsulfonium chloride being preferred.

[0057] Specific examples of crown ethers include 18-crown-6, dibenzo-18-crown-6, and dicyclohexyl-18-crown-6.

[0058] <Specific organic solvent> The specific organic solvent is an organic solvent having a relative dielectric constant of 30 or more. The specific organic solvent has a relative dielectric constant of 30 or more, and from the viewpoint of obtaining superior effects of the present invention, it is preferably 37 or more, particularly preferably 40 or more, and is preferably 120 or less, particularly preferably 60 or less. Examples of specific organic solvents include dimethyl sulfoxide (DMSO) (47.2), acetonitrile (36.6), nitromethane (37.3), nitrobenzene (35.6), and methanol (33.0). Dimethyl sulfoxide, acetonitrile, and nitromethane are preferred, and dimethyl sulfoxide and acetonitrile are particularly preferred, in view of further improving the reaction yield and the reaction rate of 244ca. The specific organic solvent may be used alone or in combination of two or more kinds. The dielectric constant of a specific organic solvent can be confirmed by referring to the Chemical Handbook, Basic Edition, 5th Revised Edition, edited by the Chemical Society of Japan, I-770~777.

[0059] <Manufacturing process> In the production method of the present invention, 244ca reacts with a base in the presence of a base, a phase transfer catalyst, and a specific organic solvent, causing a dehydrofluorination reaction of 244ca to produce 1233yd.

[0060] The production method of the present invention may be carried out as a solid-phase reaction or a liquid-phase reaction, but is preferably carried out as a liquid-phase reaction from the viewpoints of the better reaction rate, 1233yd yield and selectivity. Here, the solid-phase reaction includes a method of contacting a solid base with gaseous 244ca, and the liquid-phase reaction includes a method of contacting a base contained in a base solution (preferably an aqueous base solution) with liquid 244ca.

[0061] The production method of the present invention may be carried out in a batch manner, or in a semi-continuous or continuous flow manner. The reaction time can be appropriately adjusted depending on the mode.

[0062] An example of the manufacturing method of the present invention will be described. First, a base, a phase transfer catalyst, a specific organic solvent and 244ca are introduced into a reactor, and each component is mixed in the reactor. As a result, the dehydrofluorination reaction of 244ca proceeds in the reactor, and a reaction liquid containing 1233yd and the specific organic solvent is obtained. When the dehydrofluorination reaction is carried out as a liquid phase reaction, it is preferable to use water as a solvent in order to more effectively exert the effects of the present invention. The solvent can be introduced into the reactor in the form of the above-mentioned base solution (preferably an aqueous base solution). When water is used in this way, the dehydrofluorination reaction of 244ca proceeds at the interface between the aqueous phase containing the base and the organic phase containing 244ca, so it is preferable to mix the components with a stirring means (e.g., a static mixer) so that the base and 244ca are in good contact with each other.

[0063] Next, 1233yd contained in the reaction solution discharged from the reactor is recovered. Specifically, when an aqueous base solution is used, the reaction solution is allowed to stand after completion of the reaction to separate into an organic phase and an aqueous phase, and then 1233yd contained in the organic phase is recovered by a separation and purification method such as distillation. According to the production method of the present invention, the selectivity of 1-chloro-3,3-difluoropropyne can be reduced to 0.2% or less, which facilitates separation and purification of 1233yd contained in the organic phase. Here, the organic phase contains a specific organic solvent and 1233yd, and may contain by-products such as unreacted 244ca and 1-chloro-3,3-difluoropropyne. When the product contains 244ca, it is preferable to perform a highly accurate distillation since the boiling points of 244ca and 1233yd(Z) are close. In addition, in order to increase the purity of 1233yd(Z) and 1233yd(E), separation of the E and Z isomers of 1233yd may be performed by a separation and purification method such as distillation. The aqueous phase contains water and may contain a specific organic solvent, solvent, 1233yd, etc.

[0064] The specific organic solvent may be partially decomposed, and the decomposition product may be contained in the organic phase or the aqueous phase. The decomposition product contained in the organic phase may be separated from 1233yd by a separation and purification method such as distillation, a water washing treatment in which the decomposition product is washed with water, a solid adsorption treatment in which the decomposition product is brought into contact with a solid adsorbent, or a combination of these. Examples of the solid adsorbent include activated carbon, zeolite, silica, alumina, etc. Two or more types of solid adsorbents may be used in combination.

[0065] In addition, when DMSO is used as the specific organic solvent, a part of the DMSO may decompose and be contained in the organic phase or the aqueous phase as dimethyl sulfide. The dimethyl sulfide contained in the organic phase can be separated from 1233yd by a separation and purification method such as distillation, a water washing treatment in which the dimethyl sulfide is washed with water, a solid adsorption treatment in which the dimethyl sulfide is brought into contact with a solid adsorbent, or a combination of these. Examples of solid adsorbents include activated carbon, zeolite, silica, alumina, etc. Two or more types of solid adsorbents may be used in combination. Activated carbon is preferably used because it has high adsorption properties for dimethyl sulfide. After the separation operation, the content of dimethyl sulfide is preferably 0.1 to 10 mass ppm, more preferably 0.3 to 5 mass ppm, and even more preferably 0.5 to 3 mass ppm, based on the total amount of the composition containing 1233yd. If it is equal to or more than the lower limit, it is advantageous in terms of production costs and can reduce the odor specific to the solvent. If it is equal to or less than the upper limit, it can reduce the irritating odor caused by dimethyl sulfide.

[0066] According to the production method of the present invention, the reaction solution is also excellent in terms of two-layer separation. Although the details of the reason for this are not clear, it is presumed to be due to the action of the specific organic solvent. If the reaction solution has excellent two-phase separation properties, there are advantages such as easy recovery of 1233yd, easy reuse of each component, and shortening of process time.

[0067] By separating and purifying the 1233yd obtained by the production method of the present invention as described above and recovering it, a purified 1233yd containing 1233yd at a high purity can be obtained. If the purified 1233yd contains acids such as HCl, water, or oxygen, the equipment may corrode during use, or the stability of the 1233yd may decrease. Therefore, the content of acids, that is, chloride ions and fluorine ions, is preferably less than 10 ppm by mass, more preferably less than 1 ppm by mass, and most preferably less than 0.1 ppm by mass, based on the total amount of the purified 1233yd. The water concentration in the purified 1233yd is preferably 2000 ppm by mass, more preferably less than 1500 ppm by mass, even more preferably 1000 ppm by mass, and most preferably less than 100 ppm by mass. The oxygen concentration in the purified 1233yd is preferably 1000 ppm by mass or less, and particularly preferably 500 ppm by mass or less. Outside the above range, decomposition of 1233yd may occur, and the degreasing and cleaning performance may be impaired.

[0068] The material of the reactor is not particularly limited as long as it is inert to the components used in the production method of the present invention and to the components contained in the reaction liquid obtained after the reaction, and is corrosion-resistant. Specific examples of materials for the reactor include glass, iron, nickel, and alloys containing iron as a main component, such as stainless steel.

[0069] The reaction temperature in the dehydrofluorination reaction is preferably 40 to 90°C, and from the viewpoint of obtaining better effects of the present invention and further improving the reaction rate, it is more preferably 45°C or higher, even more preferably 55°C or higher, and particularly preferably 60°C or higher; and from the viewpoint of obtaining better effects of the present invention and further improving the selectivity for 1233yd, it is more preferably 80°C or lower, even more preferably 75°C or lower, and particularly preferably 70°C or lower.

[0070] The 1233yd obtained by the production method of the present invention may be either the E-isomer or the Z-isomer, or a mixture of these. Here, the boiling point of 244ca is 53°C, the boiling point of 1233yd(Z) is 54°C, and the boiling point of 1233yd(E) is 47 to 48°C. Specific examples of uses of 1233yd obtained by the production method of the present invention include cleaning agents, refrigerants, foaming agents, solvents, and aerosols.

[0071] The specific organic solvent contained in the organic phase of the above-mentioned reaction solution can be recovered and reused as the specific organic solvent used in the production method of the present invention. According to the production method of the present invention, the reaction solution has excellent two-phase separation, and therefore the specific organic solvent can be recovered with excellent efficiency. Specifically, a method includes recovering the specific organic solvent from a reaction liquid containing 1233yd and the specific organic solvent obtained as described above, and carrying out a dehydrofluorination reaction of 244ca in the presence of the recovered specific organic solvent, a phase transfer catalyst, and a base to produce 1233yd. A specific example of a method for recovering a specific organic solvent from a reaction liquid is a method for separating and purifying an organic phase contained in the reaction liquid (for example, distillation).

[0072] In addition, if unreacted 244ca remains, it is possible to concentrate the 244ca by distillation and reuse it as a raw material in the production method of the present invention.

[0073] <Amount used and content ratio> The amount of base used is preferably 0.8 to 3.0 mol, more preferably 1.0 to 2.5 mol, and particularly preferably 1.2 to 2.0 mol, per mol of 244ca. If the amount is equal to or more than the lower limit, the yield and selectivity of 1233yd are excellent, and if the amount is equal to or less than the upper limit, the volumetric efficiency of the reaction is excellent. When the base is used in the form of the above-mentioned base solution (preferably an aqueous base solution), the concentration of the base in the base solution is preferably 20 to 55 mass%, more preferably 30 to 48 mass%, and particularly preferably 38 to 44 mass%. If the concentration is equal to or higher than the lower limit, the reaction rate can be improved, and if the concentration is equal to or lower than the upper limit, the production of propyne can be reduced, and the selectivity of 1233yd can be improved. When the base is used in the form of the above-mentioned base solution (preferably an aqueous base solution), the amount of the solvent (preferably water) used is preferably 98 to 300 parts by mass, particularly preferably 103 to 200 parts by mass, relative to the amount (100 parts by mass) of 244ca used. When the amount of water used is within the above range, the two-layer separation property of the reaction liquid is more excellent.

[0074] The amount of phase transfer catalyst used is preferably 0.1 to 3 parts by mass, more preferably 0.1 to 2 parts by mass, and even more preferably 0.5 to 1.5 parts by mass, relative to the amount of 244ca used (100 parts by mass). If it is equal to or greater than the lower limit, the conversion rate of 244ca and the yield of 1233yd are improved. If it is equal to or less than the upper limit, the two-layer separation is excellent and it is also advantageous in terms of cost. The amount of the specific organic solvent used is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass, and particularly preferably 10 to 20 parts by mass, relative to the amount of 244ca used (100 parts by mass). If it is equal to or more than the lower limit, the production of propyne can be further reduced, and the reaction rate and the two-phase separation property of the reaction solution are more excellent. If it is equal to or less than the upper limit, the two-phase separation property and the volumetric efficiency of the reaction are excellent, and it is also advantageous in terms of cost.

[0075] The mass ratio of the amount of the phase transfer catalyst to the amount of the specific organic solvent (phase transfer catalyst / specific organic solvent) is preferably 0.020 to 0.20, more preferably 0.020 to 0.090, and even more preferably 0.040 to 0.070. If it is equal to or greater than the lower limit, the reaction can proceed efficiently. If it is equal to or less than the upper limit, the two-layer separation of the reaction solution is more excellent, and the production of propyne can be reduced. When the base is used in the form of the above-mentioned base solution (preferably an aqueous base solution), the mass ratio of the amount of the specific organic solvent used to the amount of the solvent (preferably water) used (amount of the specific organic solvent used / amount of the solvent used) is preferably 0.01 to 0.50, more preferably 0.05 to 0.30, and particularly preferably 0.08 to 0.16. If it is equal to or greater than the lower limit, the production of propyne can be further reduced, and the reaction can proceed efficiently. If it is equal to or less than the upper limit, the two-layer separation property of the reaction solution is more excellent. EXAMPLES

[0076] The present invention will be described in detail below with reference to examples. Examples 1-1 to 1-3 and 2-1 to 2-8 are working examples, and Examples 1-4 and 2-9 are comparative examples. However, the present invention is not limited to these examples.

[0077] [Gas chromatography conditions] In the synthesis of the following compounds, the composition of the reaction products was analyzed by gas chromatography (GC). A DB-1301 column (length 60 m × inner diameter 250 μm × thickness 1 μm, manufactured by Agilent Technologies, Inc.) was used.

[0078] [Conversion rate, selectivity, yield] Based on the above GC measurement results, the conversion, selectivity and yield were calculated. The conversion rate indicates the ratio (unit: %) of the molar amount of the raw material (244ca) consumed in the reaction to the molar amount of the raw material (244ca unless otherwise specified) used in the reaction. The selectivity refers to the ratio (unit: %) of the amount (molar amount) of the product (1233 yd or 1-chloro-3,3-difluoropropyne) produced to the total amount of the products. The yield (%) is the ratio (unit: %) of the molar amount of the product (1,233 yd) recovered from the organic phase obtained in the reaction to the molar amount of 244ca introduced into the reaction system.

[0079] [Reaction rate constant] The reaction rate constant was calculated by the least squares method so as to minimize the difference between the conversion rate experimentally determined from the 244ca concentration at each time and the conversion rate calculated from the following reaction rate equation. Reaction rate equation: -d[244ca] / dt=k[244ca][KOH] In the formula, k is the rate constant, t is time, [244ca] is the concentration of 244ca, and [KOH] is the concentration of KOH.

[0080] [Evaluation of biphasic separation] After the reaction to obtain 1233yd was completed, the reaction solution containing the organic phase and the aqueous phase was allowed to stand for 1 hour, and then the reaction solution was visually observed to evaluate the two-layer separability according to the following criteria. ○: The interface between the organic phase and the aqueous phase is clear. △: A small amount of emulsion or solid floating matter was observed at the interface between the organic phase and the aqueous phase. ×: Most or all of the solution is an emulsion.

[0081] [Production of 244ca] 244ca was prepared by the following method, which involves chlorinating TFPO with thionyl chloride to give 244ca, as shown in Scheme 2 above.

[0082] <Synthesis of 244ca> 1204g (9.12 mol) of TFPO and 12g (0.17 mol) of N,N-dimethylformamide (DMF) were added to a 2-liter four-neck flask equipped with a glass distillation column (measured plate number: 5) filled with an agitator, a Dimroth filter, a condenser, and Raschig rings. 1078g (0.12 mol) of thionyl chloride was added dropwise and stirred at room temperature for 12 hours. The reactor was then heated to 100°C, and reactive distillation was performed with a reflux time / distillation time ratio of 5 / 1 using a reflux timer. The distilled 244ca was neutralized with a 20% by mass potassium hydroxide aqueous solution. The recovered 244ca (100% purity) was 979g (6.50 mol).

[0083] [Example 1-1] In an autoclave equipped with a stirrer, 52.9 g of the 244ca obtained as described above, 0.529 g of tetra-n-butylammonium bromide (TBAB) as a phase transfer catalyst, 7.935 g of dimethyl sulfoxide (DMSO) as a specific organic solvent, and 131.3 g of 30 mass% potassium hydroxide (KOH) aqueous solution were placed, and the autoclave was heated to 70°C. The reaction temperature was maintained at 70°C, and stirring was continued for 4 hours (reaction time), after which a reaction liquid containing an organic phase and an aqueous phase was obtained. Using the obtained reaction liquid, the above-mentioned evaluation of two-layer separation property was carried out. In addition, the organic phase recovered from the reaction mixture was washed with water and then analyzed by gas chromatography to calculate the conversion, selectivity and yield.

[0084] [Examples 1-2 to 1-4, Examples 2-1 to 2-9] The reaction liquids and organic phases in Examples 1-2 to 1-4 and Examples 2-1 to 2-9 were obtained in the same manner as in Example 1-1, except that the amounts of each component used and the reaction conditions were changed as shown in the following Table 1. Using the obtained reaction liquids and organic phases, the same evaluations as in Example 1-1 were carried out. In Table 1, MeCN means acetonitrile, and MeNO2 means nitromethane.

[0085] The evaluation results are shown in Table 1. In Table 1, KOH concentration means the concentration of KOH in the KOH aqueous solution. KOH equivalent means the amount (mol) of KOH used per mole of 244ca. The amounts of water, TBAB, and the specific organic solvent used all mean the amounts (parts by mass) used per 100 parts by mass of 244ca used. A / B means the mass ratio of the amount of TBAB used to the amount of specific organic solvent used, and B / C means the mass ratio of the amount of specific organic solvent used to the amount of water used.

[0086] [Table 1]

[0087] As shown in Table 1, when 1233yd was produced by dehydrofluorination of 244ca in the presence of a phase transfer catalyst, an organic solvent having a dielectric constant of 30 or more, and a base, it was confirmed that the amount of propyne produced could be reduced and the conversion rate of the raw material 244ca was excellent (Examples 1-1 to 1-3 and Examples 2-1 to 2-8).

[0088] Activated carbon (Carborafine, manufactured by Osaka Gas Chemicals Co., Ltd.) was added in an amount of 10% by mass to the composition produced in Example 2-4 (1233yd: 99.9% by mass, dimethyl sulfide: 14 ppm by mass), and the mixture was immersed at 25° C. for 3 days. The activated carbon was then removed by filtration, and the composition was recovered. When the recovered composition was analyzed by gas chromatography, it was found that 1233yd was 99.9% by mass, dimethyl sulfide was 2.6 ppm by mass, and the recovery rate of 1233yd was 90.1%.

[0089] The composition produced in Example 2-2 (1233 yd: 99.9 mass%, dimethyl sulfide: 184 mass ppm) was distilled, and the distillate was recovered. The recovered distillate was analyzed by gas chromatography, and it was found that 1233yd was 99.9% by mass, dimethyl sulfide was 0.6 ppm by mass, and the recovery rate of 1233yd was 85.3%.

[0090] The entire contents of the specification, claims, drawings and abstract of Japanese Patent Application No. 2019-235660, filed on December 26, 2019, are hereby incorporated by reference as the disclosure of the specification of the present invention.

Claims

1. A method for producing 1-chloro-2,3,3-trifluoropropene, comprising dehydrofluorinating 3-chloro-1,1,2,2-tetrafluoropropane in the presence of a phase transfer catalyst, an organic solvent having a dielectric constant of 30 or more, and a base, The organic solvent is at least one selected from the group consisting of dimethyl sulfoxide, acetonitrile, and nitromethane; the phase transfer catalyst is a quaternary ammonium salt; A process for the preparation of 1-chloro-2,3,3-trifluoropropene, which is carried out in a liquid phase reaction and uses water as a solvent.

2. The method for producing 1-chloro-2,3,3-trifluoropropene according to claim 1, wherein a mass ratio of the amount of the phase transfer catalyst to the amount of the organic solvent is 0.020 to 0.

20.

3. The method for producing 1-chloro-2,3,3-trifluoropropene according to claim 1 or 2, wherein a mass ratio of the amount of the phase transfer catalyst to the amount of the organic solvent is 0.020 to 0.

090.

4. The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of claims 1 to 3, wherein a mass ratio of the amount of the organic solvent used to the amount of the water used is 0.01 to 0.

50.

5. The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of claims 1 to 4, wherein the organic solvent is at least one of dimethyl sulfoxide and acetonitrile.

6. The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of claims 1 to 5, wherein the base is at least one of potassium hydroxide and sodium hydroxide.

7. The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of claims 1 to 6, wherein the reaction temperature in the dehydrofluorination reaction is 40 to 90°C.

8. The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of claims 1 to 7, wherein the dehydrofluorination reaction proceeds at an interface between an aqueous phase containing a base and an organic phase containing 3-chloro-1,1,2,2-tetrafluoropropane.

9. The base is used in the form of a base solution, and the amount of the solvent used in the base solution is 98 to 300 parts by mass relative to the amount (100 parts by mass) of 3-chloro-1,1,2,2-tetrafluoropropane used, The amount of the phase transfer catalyst used is 0.1 to 3 parts by mass relative to the amount of 3-chloro-1,1,2,2-tetrafluoropropane used (100 parts by mass), The method for producing 1-chloro-2,3,3-trifluoropropene according to any one of claims 1 to 8, wherein the amount of the organic solvent used is 1 to 30 parts by mass relative to the amount of 3-chloro-1,1,2,2-tetrafluoropropane used (100 parts by mass).

10. A method for producing 1-chloro-2,3,3-trifluoropropene, comprising recovering the organic solvent from a reaction solution containing the 1-chloro-2,3,3-trifluoropropene produced by the method for producing 1-chloro-2,3,3-trifluoropropene according to any one of claims 1 to 9 and the organic solvent, and then subjecting 3-chloro-1,1,2,2-tetrafluoropropane to a dehydrofluorination reaction in the presence of the recovered organic solvent, a phase transfer catalyst, and a base.

11. A method for producing 1-chloro-2,3,3-trifluoropropene, comprising obtaining a reaction liquid containing 1-chloro-2,3,3-trifluoropropene by the method according to any one of claims 1 to 10, and separating 1-chloro-2,3,3-trifluoropropene from the reaction liquid.

12. The method for separating 1-chloro-2,3,3-trifluoropropene from the reaction solution is at least one method selected from the group consisting of a separation and purification method, a water washing treatment, and a solid adsorption treatment. The method for producing 1-chloro-2,3,3-trifluoropropene according to claim 11.

13. The method for producing 1-chloro-2,3,3-trifluoropropene according to claim 12, wherein the solid adsorption treatment is carried out with at least one selected from activated carbon, zeolite, silica, and alumina.

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