Method for producing 1, 1, 2, 2-tetrafluorocyclobutane, and method for producing vinylidene fluoride

Abstract

A method for producing 1, 1, 2, 2-tetrafluorocyclobutane, said method comprising a reaction step in which a compound represented by formula 1 and ethylene are reacted using a starting material composition comprising the compound represented by formula 1 and ethylene. In the formula 1, X1 is a hydrogen atom, a fluorine atom or a chlorine atom, and X2 is a fluorine atom, a chlorine atom,-CO2H,-CF3 or-CF2Cl.

Description

Technical Field

[0001] This invention relates to a method for manufacturing 1,1,2,2-tetrafluorocyclobutane. Background Technology

[0002] 1,1,2,2-Tetrafluorocyclobutane is useful, for example, as a foaming agent, refrigerant, solvent, etchant, or as a raw material for obtaining vinylidene fluoride.

[0003] For example, Non-Patent Document 1 describes obtaining hexafluorocyclopropane by ultraviolet irradiation of a mixture containing tetrafluoroethylene and ethylene at a temperature of 180°C, and describes obtaining a mixture containing 1,1,2,2-tetrafluorocyclobutane by using a mixture containing hexafluorocyclopropane and ethylene at a temperature of 300°C.

[0004] Existing technical documents

[0005] Non-patent literature

[0006] Non-patent literature 1: JMBirchall et al., Journal of Fluorine Chemistry, 1980, vol.15, pp.487-495

[0007] Non-patent literature 2: Makoto Kuzumi et al., Japanese Chemical Journal, 1979, 12, 1749-1755. Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, the method described in Non-Patent Document 1 involves multiple steps in obtaining 1,1,2,2-tetrafluorocyclobutane from tetrafluoroethylene, and a simpler method for obtaining 1,1,2,2-tetrafluorocyclobutane is required.

[0010] One objective of this disclosure is to provide a method for producing 1,1,2,2-tetrafluorocyclobutane with fewer reaction steps (i.e., fewer reaction steps) than conventional manufacturing methods.

[0011] Another objective of this disclosure is to provide a method for manufacturing vinylidene fluoride using the above-described method for manufacturing 1,1,2,2-tetrafluorocyclobutane.

[0012] Solution for solving the problem

[0013] This disclosure includes the following methods.

[0014] <1>

[0015] A method for producing 1,1,2,2-tetrafluorocyclobutane includes the following reaction step: using a raw material composition comprising a compound represented by Formula 1 and ethylene, reacting the compound represented by Formula 1 with ethylene.

[0016]

[0017] In Equation 1, X 1 X is a hydrogen atom, a fluorine atom, or a chlorine atom. 2 It can be a fluorine atom, a chlorine atom, -CO2H, -CF3, or -CF2Cl.

[0018] <2>

[0019] according to <1> The method for producing 1,1,2,2-tetrafluorocyclobutane, wherein the compound represented by Formula 1 contains difluoromethane chloride.

[0020] <3>

[0021] according to <1> or <2> The method for producing 1,1,2,2-tetrafluorocyclobutane, wherein the reaction process is carried out in the presence of a hot medium gas.

[0022] <4>

[0023] according to <3> The method for producing 1,1,2,2-tetrafluorocyclobutane, wherein the heat medium gas includes water vapor.

[0024] <5>

[0025] according to <3> or <4> The method for producing 1,1,2,2-tetrafluorocyclobutane, wherein the content of the heat transfer gas is 80 mol% or more relative to the total content of the compound shown in Formula 1, ethylene, and the heat transfer gas.

[0026] <6>

[0027] according to <1> ~ <5> The method for producing 1,1,2,2-tetrafluorocyclobutane according to any one of the following, wherein the molar amount of ethylene in the raw material composition is 4.0 or less relative to the molar amount of the compound shown in Formula 1.

[0028] <7>

[0029] according to <1> ~ <6> The method for producing 1,1,2,2-tetrafluorocyclobutane according to any one of the following methods, wherein the temperature inside the reactor used in the reaction step is below 900°C.

[0030] <8>

[0031] according to <1> ~ <7> The method for producing 1,1,2,2-tetrafluorocyclobutane according to any one of the following methods, wherein the contact time between the compound represented by Formula 1 and ethylene is 0.1 seconds or more.

[0032] <9>

[0033] according to <1> ~ <8> The method for producing 1,1,2,2-tetrafluorocyclobutane according to any one of the following, wherein, in the reaction step, the pressure inside the reactor is 0 MPaG or higher.

[0034] <10>

[0035] A method for manufacturing vinylidene fluoride, comprising: using <1> ~ <9> The method for manufacturing 1,1,2,2-tetrafluorocyclobutane according to any one of the following methods comprises the steps for manufacturing 1,1,2,2-tetrafluorocyclobutane; and

[0036] The process of manufacturing vinylidene fluoride using a feedstock composition A containing 1,1,2,2-tetrafluorocyclobutane obtained by a method for manufacturing 1,1,2,2-tetrafluorocyclobutane.

[0037] The effects of the invention

[0038] According to one embodiment of the present disclosure, a method for producing 1,1,2,2-tetrafluorocyclobutane is provided, which can obtain 1,1,2,2-tetrafluorocyclobutane with a shorter reaction process than conventional manufacturing methods.

[0039] According to another embodiment of this disclosure, a method for manufacturing vinylidene fluoride using the above-described method for manufacturing 1,1,2,2-tetrafluorocyclobutane is provided. Attached Figure Description

[0040] Figure 1 This is a schematic structural diagram illustrating an example of a manufacturing apparatus. Detailed Implementation

[0041] In this disclosure, the numerical range represented by “~” refers to the range in which the values ​​recorded before and after “~” are respectively the minimum and maximum values.

[0042] In the numerical ranges described in stages in this invention, the upper or lower limit value recorded in a certain numerical range can be replaced with the upper or lower limit value of other numerical ranges described in stages. Furthermore, in the numerical ranges described in this invention, the upper or lower limit value recorded in a certain numerical range can be replaced with the values ​​shown in the embodiments.

[0043] In this invention, a combination of two or more preferred methods is a more preferred method.

[0044] In this invention, when there are multiple substances equivalent to each component, unless otherwise specified, the amount of each component refers to the total amount of the multiple substances.

[0045] [C354 Manufacturing Method]

[0046] The method for producing 1,1,2,2-tetrafluorocyclobutane (C354) disclosed herein includes the following reaction steps: using a raw material composition comprising a compound represented by Formula 1 and ethylene, reacting the compound represented by Formula 1 with ethylene.

[0047]

[0048] In Equation 1, X 1 X is a hydrogen atom, a fluorine atom, or a chlorine atom. 2 It can be a fluorine atom, a chlorine atom, -CO2H, -CF3, or -CF2Cl.

[0049] According to the manufacturing method of C354 of the present invention, C354 can be obtained with a shorter reaction process than conventional manufacturing methods.

[0050] In the method described in Non-Patent Document 1, hexafluorocyclopropane is obtained by ultraviolet irradiation of a mixture containing tetrafluoroethylene and ethylene, and then C354 is obtained by using a mixture containing hexafluorocyclopropane and ethylene at a temperature of 300°C. The reaction process is multi-stage.

[0051] In contrast, the inventors focused on the compound shown in Formula 1 and discovered that by reacting the compound shown in Formula 1 with ethylene, c354 can be obtained with a shorter reaction step than conventional manufacturing methods.

[0052] It should be noted that Non-Patent Document 2 describes a method for synthesizing vinylidene fluoride using the gas-phase thermal decomposition of dichlorofluoromethane (R22) and ethylene, but does not describe the generation of C354. Furthermore, when synthesizing vinylidene fluoride using these methods, low-boiling-point components containing carbon monoxide are produced as byproducts, which are difficult to separate from vinylidene fluoride. On the other hand, in the manufacturing method of the present invention, the main objective is the synthesis of C354 as a high-boiling-point compound; therefore, even if low-boiling-point components are produced as byproducts, they are easily separated. In addition, it is known that the selectivity is high when synthesizing vinylidene fluoride from recovered C354. Therefore, from a purification point of view, synthesizing C354 as an intermediate and recovering it is a superior method compared to the method of direct synthesis from the raw material, in the synthesis of vinylidene fluoride from R22 and ethylene.

[0053] <Raw Material Composition>

[0054] In the reaction step of the method for manufacturing C354 of the present invention, a raw material composition comprising the compound shown in Formula 1 and ethylene is used to react the compound shown in Formula 1 with ethylene.

[0055] A raw material composition refers to a substance that directly or indirectly generates C354. "Directly" indicates that the raw material composition generates C354 through a single reaction, while "indirectly" indicates that the raw material composition generates C354 through multiple reactions.

[0056] The raw material composition may contain only one compound represented by Formula 1 or more compounds.

[0057] Examples of compounds represented by Formula 1 include the following compounds.

[0058]

[0059] From the viewpoint of reactivity and ease of acquisition, the compound shown in Formula 1 preferably contains R22.

[0060] Furthermore, the proportion of R22 in the compound shown in Formula 1 is preferably 50 mol% or more, more preferably 90 mol% or more. The compound shown in Formula 1 may consist of only R22.

[0061] It should be noted that, as a method for manufacturing C354, another example is a method of reacting at least one of the compounds in group A (described below) with ethylene using a raw material composition.

[0062] Compound group A consists of the following compounds, polytetrafluoroethylene (PTFE), and oligomers of PTFE. Among the following compounds, X... 3 Each ion can be independently a fluorine, chlorine, bromine, or iodine atom. Examples of ions with the same atom include alkali metals, alkaline earth metals, and noble metals. Examples of alkali metal ions include lithium, sodium, and potassium ions. Examples of alkaline earth metal ions include magnesium and calcium ions. Examples of transition metal ions include silver and copper ions. R 1 Each can be an alkyl group (e.g., methyl, ethyl, n-propyl, isopropyl, etc.).

[0063]

[0064] The feedstock composition comprises the compound shown in Formula 1 and ethylene. From the viewpoint of improving yield, the molar ratio of ethylene to the molar ratio of the compound shown in Formula 1 in the feedstock composition is preferably 20 or less, more preferably 10 or less, and even more preferably 4.0 or less. The lower limit of the above ratio is not particularly limited, for example, it is 0.1.

[0065] The raw material composition may contain other components besides the compound shown in Formula 1 and ethylene. These other components may be at least one of the compounds in group A described above.

[0066] The total proportion of the compound shown in Formula 1 and ethylene in the raw material composition is preferably 50 mol% or more, more preferably 90 mol% or more. The raw material composition may consist only of the compound shown in Formula 1 and ethylene.

[0067] <Reaction Conditions>

[0068] From the perspective of polymerization reaction, inhibiting carbonization, and preventing blockage of the reaction tubes, the reaction process is preferably carried out in the presence of a heat transfer gas. The heat transfer gas acts as a diluent in the reaction process.

[0069] In this invention, the heat medium gas refers to a medium that does not substantially decompose when alone at the temperature inside the reactor. Specifically, it is desirable for a medium that does not substantially decompose when alone at a temperature of 100 to 1000°C.

[0070] Examples of gases that can be used as heat transfer media include rare gases such as helium and argon; nitrogen; carbon dioxide; perfluoroalkyl compounds such as tetrafluoromethane; and water vapor.

[0071] The heat transfer medium gas can be a single type or two or more types.

[0072] From the viewpoint of separability from C354, the heat transfer medium gas preferably contains water vapor, more preferably water vapor. Furthermore, when using R22 as a feedstock, hydrogen chloride is produced as a byproduct, but water vapor has the effect of suppressing hydrogen chloride-based side reactions. Therefore, the heat transfer medium gas preferably contains water vapor, more preferably water vapor.

[0073] From the viewpoint of polymerization reaction and inhibition of carbonization, the content of the heat transfer gas relative to the total content of the compound shown in Formula 1, ethylene, and the heat transfer gas is preferably 30 mol% or more, more preferably 50 mol% or more, further preferably 70 mol% or more, and particularly preferably 80 mol% or more. The upper limit of the heat transfer gas content is, for example, 99 mol%.

[0074] As a reactor used in the reaction process, its shape and structure are not particularly limited, as long as it can withstand the temperature and pressure inside the reactor (described later). For example, a cylindrical vertical reactor can be used. As for the material of the reactor, stainless steel, glass, and alloys with iron, nickel, or chromium as the main components can be used. The reactor can be equipped with a heating unit such as an electric heater to heat the interior.

[0075] The compound shown in Formula 1 and ethylene can be directly introduced into the reactor at room temperature. However, to improve reactivity within the reactor, they can also be heated (preheated) before being introduced. When preheating, the compound shown in Formula 1 is preferably heated to a temperature of 50–300°C before being supplied to the reactor. Ethylene is preferably heated to a temperature of 50–300°C before being supplied to the reactor.

[0076] In addition, the components contained in the raw material composition can be pre-mixed and then supplied to the reactor, or they can be supplied to the reactor separately and mixed in the reactor.

[0077] From the viewpoint of reaction efficiency, the temperature inside the reactor during the reaction process is preferably 200–1000°C. In particular, from the viewpoint of reaction efficiency, the temperature inside the reactor is preferably below 900°C, more preferably 450–900°C, and even more preferably 500–900°C.

[0078] The reaction process can be carried out either batch or continuous. From a productivity point of view, the reaction process is preferably carried out continuously, and it is preferable to control the contact time in a continuous process.

[0079] From the viewpoint of reaction efficiency, the contact time between the compound represented by Formula 1 and ethylene is preferably 0.1 seconds or more, more preferably 0.5 seconds or more. The upper limit of the contact time is, for example, 300 seconds.

[0080] Contact time can also be described as residence time within the reactor. The contact time (in seconds) mentioned above is calculated using the following formula.

[0081] Contact time (seconds) = [Volume of feed composition supplied to the reactor at the reaction temperature per second] / [Volume of reactor]

[0082] From the perspective of reaction efficiency, the pressure inside the reactor during the reaction process is preferably above 0 MPaG. There is no particular upper limit to the pressure; it is the pressure that the reactor can withstand, for example, 0.6 MPaG.

[0083] It should be noted that, in this invention, pressure expressed in MPaG is gauge pressure.

[0084] In the method for manufacturing C354 disclosed herein, it can be obtained in the form of a crude product containing C354. In addition to C354, the crude product may also contain the compound shown in Formula 1 and ethylene. C354 can be separated from the crude product, and the separated crude product (containing the compound shown in Formula 1 and ethylene) can be used in a reaction step. That is, the compound shown in Formula 1 and ethylene contained in the crude product can be recycled.

[0085] The C354 obtained by the manufacturing method of the present invention is preferably used as a raw material in the process of manufacturing vinylidene fluoride.

[0086] Specifically, as one embodiment of this disclosure, the method for manufacturing vinylidene fluoride preferably includes: a step of manufacturing C354 using the above-described method for manufacturing C354; and a step of manufacturing vinylidene fluoride using a raw material composition A containing C354 obtained by the above-described method for manufacturing C354.

[0087] According to the method for manufacturing vinylidene fluoride as an embodiment of this disclosure, vinylidene fluoride can be manufactured using a raw material composition A containing C354. After obtaining C354 using the method for manufacturing C354 of the present invention, vinylidene fluoride can then be manufactured from C354.

[0088] Example

[0089] The present disclosure will be specifically described below through embodiments, but the present disclosure is not limited to these embodiments.

[0090] [Example 1]

[0091] use Figure 1 The manufacturing apparatus 100 shown uses a raw material composition consisting of R22 and ethylene, as well as steam (water vapor), to obtain c354 by the method shown below.

[0092] R22 is supplied from R22 tank 1 to mixer 7 via R22 supply line 3.

[0093] In addition, ethylene is supplied from ethylene tank 2 to mixer 7 via ethylene supply line 4.

[0094] R22 and ethylene are mixed using mixer 7. Then, R22 and ethylene are continuously introduced into an Inconel 600 tube in preheater 12, where the furnace temperature is set to 200°C (“preheating temperature” in the table), via feedstock supply line 11, and heated to 200°C.

[0095] Then, water is supplied from water tank 8 to preheater 13 via water supply line 9. The water is heated by preheater 13, which is set to a furnace temperature of 600°C, to produce steam (water vapor).

[0096] The R22 and ethylene, which are preheated to the above temperature, and the steam (water vapor) are adjusted to ethylene / R22 = 1.0 (molar ratio), and the overall supply ratio of water vapor to the gas supply is water vapor / (ethylene + R22 + water vapor) × 100 = 80 mol%, which is supplied to reactor 14 with an internal pressure (gauge pressure) of 0 MPaG and an internal temperature of 600°C.

[0097] Inside reactor 14, the flow rates (supply per unit time) of R22 and ethylene are controlled such that the contact time between R22 and ethylene and water vapor is 0.6 seconds.

[0098] The gas supply is adjusted by the R22 flow control device 5, the ethylene flow control device 6, and the water flow control device 10.

[0099] The outlet gas discharged from reactor 14 contains, in addition to gases generated or produced by the reaction, unreacted raw material composition.

[0100] The outlet gas is recovered via the outlet gas supply / cooling line 15 and stored in a gas tank 16. After cooling to below 100°C and separating the water vapor, a crude product is obtained. The crude product is analyzed using an analytical apparatus 17 (gas chromatography). The analytical results are shown in Table 1 along with the reaction conditions.

[0101] In addition, the molar composition of the crude product was derived from the gas chromatography analysis results. At this time, it was calculated based on the gas chromatography relative sensitivity of each component listed in Table 1, with the total of the components listed in Table 1 being 100 mol%.

[0102] [Example 2~Example 47]

[0103] The contact time, reactor temperature, preheating temperature, composition of raw material composition and hot medium gas, and reactor pressure shown in Tables 1 to 6 were changed, except that the reaction was carried out in the same manner as in Example 1.

[0104] For Examples 1 to 47, the content of each component in the obtained compositions was determined using gas chromatography (product name "6850 Series", manufactured by Agilent Technologies). The measured area ratios are shown in Tables 1 to 6. Furthermore, in Tables 1 to 6, "ethylene / R22" refers to the ratio of the molar amount of ethylene to the molar amount of R22.

[0105] [Table 1]

[0106]

[0107] [Table 2]

[0108]

[0109] [Table 3]

[0110]

[0111] [Table 4]

[0112]

[0113] [Table 5]

[0114]

[0115] [Table 6]

[0116]

[0117] As shown in Examples 1 to 47, it can be seen that using a raw material composition containing R22 and ethylene, c354 can be produced in one reaction step.

[0118] As shown in Examples 28 and 29, if the contact time is greater than 0.1 seconds, the content of C354 in the crude product increases.

[0119] As shown in Examples 24 and 25, if the molar ratio of ethylene to R22 is less than 4.0, the content of C354 in the crude product will increase.

[0120] As shown in Examples 23 and 27, when the reaction temperature is below 900℃, the content of C354 in the crude product increases.

[0121] According to Examples 7, 43-45, if the internal pressure of the reactor is above 0 MPaG, the content of c354 in the crude product will increase.

[0122] As shown in Examples 11, 46, and 47, if the content of the heat transfer medium gas (water vapor) is 80 mol% or more relative to the total content of R22, ethylene, and the heat transfer medium gas, the total content of R22, ethylene, C318, TFE, and C354 in the crude product increases. This is because if the content of the heat transfer medium gas is 80 mol% or more, carbonization is suppressed, and consequently, blockage of the reaction tube is also suppressed.

[0123] Vinylidene fluoride can be produced by heating the C354 obtained in Example 1 to above 700°C.

[0124] It should be noted that the publications of Japanese Patent Application No. 2023-043646, filed on March 17, 2023, and Japanese Patent Application No. 2023-101230, filed on June 20, 2023, are incorporated herein by reference in their entirety. Furthermore, all documents, patent applications, and technical standards described in this specification are incorporated herein by reference to the same extent as those specifically described and individually incorporated herein by reference.

Claims

1. A method for producing 1,1,2,2-tetrafluorocyclobutane, comprising the following reaction steps: using a raw material composition comprising a compound represented by Formula 1 and ethylene, reacting the compound represented by Formula 1 with the ethylene, In Equation 1, X 1 X is a hydrogen atom, a fluorine atom, or a chlorine atom. 2 It can be a fluorine atom, a chlorine atom, -CO2H, -CF3, or -CF2Cl.

2. The method for producing 1,1,2,2-tetrafluorocyclobutane according to claim 1, wherein, The compound represented by Formula 1 is dichlorofluoromethane.

3. The method for producing 1,1,2,2-tetrafluorocyclobutane according to claim 1 or 2, wherein, The reaction process is carried out in the presence of a heat transfer medium gas.

4. The method for manufacturing 1,1,2,2-tetrafluorocyclobutane according to claim 3, wherein, The heat transfer medium gas is water vapor.

5. The method for manufacturing 1,1,2,2-tetrafluorocyclobutane according to claim 3, wherein, The content of the heat transfer gas is 80 mol% or more relative to the total content of the compound shown in Formula 1, ethylene, and the heat transfer gas.

6. The method for producing 1,1,2,2-tetrafluorocyclobutane according to claim 1 or 2, wherein, In the raw material composition, the molar amount of ethylene relative to the molar amount of the compound represented by Formula 1 is 4.0 or less.

7. The method for producing 1,1,2,2-tetrafluorocyclobutane according to claim 1 or 2, wherein, The temperature inside the reactor used in the reaction process is below 900°C.

8. The method for producing 1,1,2,2-tetrafluorocyclobutane according to claim 1 or 2, wherein, The contact time between the compound represented by Formula 1 and ethylene is 0.1 seconds or more.

9. The method for producing 1,1,2,2-tetrafluorocyclobutane according to claim 1 or 2, wherein, In the reaction process, the pressure inside the reactor is above 0 MPaG.

10. A method for manufacturing vinylidene fluoride, comprising: The process of manufacturing 1,1,2,2-tetrafluorocyclobutane using the manufacturing method of 1,1,2,2-tetrafluorocyclobutane according to claim 1 or 2; and The process of manufacturing vinylidene fluoride using a feedstock composition containing 1,1,2,2-tetrafluorocyclobutane obtained by the method for manufacturing 1,1,2,2-tetrafluorocyclobutane.

Images