Method for producing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane and method for producing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane

Abstract

The present invention improves productivity of 1,2,3,4-tetrachlorohexafluorobutane by converting a by-product and the like generated by a chlorination reaction of 1,3-butadiene into a valuable substance 1,2,3,4-tetrachlorohexafluorobutane in a method for producing 1,2,3,4-tetrachlorohexafluorobutane using 1,3-butadiene as a starting raw material.　The method for producing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane involves: (a) a step for bringing a composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene into contact with chlorine (Cl2) to obtain a composition containing 1,1,2,3,4-pentachlorobutane; and (b) a step for bringing a composition containing 1,1,2,3,4-pentachlorobutane obtained in the step (a) into contact with fluorine (F2) to obtain a composition containing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane. The method for producing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane involves, in addition to the steps (a) and (b), (c) a step for bringing the composition containing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane obtained in the step (b) into contact with chlorine monofluoride (ClF) to obtain a composition containing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane.

Description

Method for producing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane and method for producing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane

[0001] The present invention relates to a method for producing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane (hereinafter simply referred to as 1,1,2,3,4-pentachloropentafluorobutane) and a method for producing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane (hereinafter simply referred to as 1,2,3,4-tetrachlorohexafluorobutane).

[0002] 1,2,3,4-Tetrachlorohexafluorobutane is an important compound as a raw material for synthesizing hexafluoro-1,3-butadiene, which is used as an etching gas in semiconductor microfabrication. Conventionally, the methods described in the following patent documents have been known as methods for producing 1,2,3,4-tetrachlorohexafluorobutane.

[0003] (1) Patent Document 1 describes CClX １ X ２ -CX ３ =CX ４ -CClX ５ X ６ , CX １ X ２ =X ３ -CClX ４ -CClX ５ X ６ , CX １ X ２ =X ３ -CX ４ =CX ５ X ６ (X １ ~X ６ are each independently a hydrogen atom or a fluorine atom) with chlorine in a liquid phase, to form a compound represented by the formula: １ X ２ -CClX ３ -CClX ４ -CClX ５ X ６ (X １ ~X ６are each independently a hydrogen atom or a fluorine atom), and then this CClX １ X ２ -CClX ３ -CClX ４ -CClX ５ X ６ (X １ ~X ６ are each independently a hydrogen atom or a fluorine atom) with fluorine in a liquid phase to produce 1,2,3,4-tetrachlorohexafluorobutane.

[0004] (2) Claim 1 of Patent Document 2 describes a method for producing 1,2,3,4-tetrachlorohexafluorobutane, characterized in that the amount of hydrogen fluoride in a solvent used in the reaction of 1,2,3,4-tetrachlorobutane with fluorine is adjusted to within a range of 10 to 60 mass %.

[0005] JP 2006-342059 A Japanese Patent No. 5274449 A

[0006] 1,2,3,4-tetrachlorobutane, the raw material for 1,2,3,4-tetrachlorohexafluorobutane, is a compound of 1,3-butadiene and chlorine (Cl ２ However, the by-products in this reaction have not been studied in detail, and therefore there has been no discussion about their effective use. ２ The same applies to by-products generated by the reaction with 1,3-butadiene. Therefore, an object of the present invention is to increase the productivity of 1,2,3,4-tetrachlorohexafluorobutane in a method for producing 1,2,3,4-tetrachlorohexafluorobutane using 1,3-butadiene as a starting material by converting by-products, etc. generated by the chlorination reaction of 1,3-butadiene into a valuable substance, 1,2,3,4-tetrachlorohexafluorobutane.

[0007] The present invention provides the following: [1] A method for producing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane, comprising: (a) reacting a composition containing at least one member selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene with chlorine (Cl ２ (b) contacting the 1,1,2,3,4-pentachlorobutane-containing composition obtained in step (a) with fluorine (F ２ [2] The composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene in the step (a) is a mixture of 1,3-butadiene and chlorine (Cl ２ [3] The method according to [1], comprising a product of a reaction of 1,3-butadiene with chlorine (Cl ２ The method according to [2], wherein the product of the reaction between 1,3-butadiene and chlorine (Cl) further contains 1,1,2,3,4-pentachlorobutane, and the concentration of 1,1,2,3,4-pentachlorobutane in the reaction solution is increased by producing 1,1,2,3,4-pentachlorobutane in the step (a). ２ The method according to [2] or [3], wherein the product of the reaction with 1,1,2,4-tetrachloro-3-butene further contains 1,1,2,4-tetrachloro-3-butene. [5] The method according to any one of [1] to [3], wherein UV irradiation is performed in the step (a). [6] A method for producing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane, comprising: (a) reacting a composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene with chlorine (Cl ２(b) contacting the 1,1,2,3,4-pentachlorobutane-containing composition obtained in step (a) with fluorine (F ２ (c) contacting the composition containing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane obtained in step (b) with chlorine monofluoride (ClF) to obtain a composition containing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane. [7] A method comprising the steps of: (a) contacting the composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene with 1,3-butadiene and chlorine (ClF) to obtain a composition containing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane. ２ [8] The method according to [6], comprising a product of a reaction of 1,3-butadiene with chlorine (Cl ２ The method according to [7], wherein the product of the reaction between 1,3-butadiene and chlorine (Cl) further contains 1,1,2,3,4-pentachlorobutane, and the concentration of 1,1,2,3,4-pentachlorobutane in the reaction solution is increased by producing 1,1,2,3,4-pentachlorobutane in the step (a). ２ The method according to any one of [7] to [8], wherein the product of the reaction with 1,1,2,4-tetrachloro-3-butene further contains 1,1,2,4-tetrachloro-3-butene.

[10] The method according to any one of [6] to [8], wherein UV irradiation is performed in the step (a).

[0008] According to the present invention, in a method for producing 1,2,3,4-tetrachlorohexafluorobutane using 1,3-butadiene as a starting material, by-products generated in the chlorination step, such as 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, 1,1,2,4-tetrachloro-3-butene, and 1,1,2,3,4-pentachlorobutane, are converted into a valuable substance, 1,2,3,4-tetrachlorohexafluorobutane, which can then be converted into hexafluoro-1,3-butadiene that can be sold as a product (the benefit of improved productivity), and the amount of industrial waste, particularly waste liquid that has been treated as a chlorine-containing organic waste liquid, can be reduced (the benefit of reduced environmental impact), which are advantageous in two respects.

[0009] (Action) The present inventors have discovered that 1,3-butadiene and chlorine (Cl) ２ ) to obtain 1,2,3,4-tetrachlorobutane, and 1,2,3,4-tetrachlorobutane and fluorine (F ２ In a method for producing 1,2,3,4-tetrachlorohexafluorobutane by reacting 1,2,3,4-tetrachloro-1,3-butadiene with 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, 1,1,2,4-tetrachloro-3-butene, and 1,1,2,3,4-pentachlorobutane are by-produced in the initial chlorination step, and further, 1,1,2,3,4-pentachloropentafluorobutane and 1,1,2,3,4,4-hexachloro-1,2,3,4-tetrafluorobutane (hereinafter simply referred to as 1,1,2,3,4,4-hexachlorotetrafluorobutane) are produced in the subsequent fluorination step, which are found to be factors contributing to the decrease in yield.

[0010]

[0011] 1,1,2,3,4-pentachloropentafluorobutane, a by-product of the fluorination process, is produced by fluorine (F) binding to the hydrogen atoms of 1,1,2,3,4-pentachlorobutane, a by-product of the chlorination process. ２ ) is substituted to form 1,2,3,4-tetrachlorobutane and fluorine (F ２It is also produced as a by-product from the reaction of 1,1,2,3,4-pentachlorobutane with fluorine (F ２ In the reaction of (1), in addition to the aforementioned 1,1,2,3,4-pentachloropentafluorobutane, 1,1,2,3,4,4-hexachlorotetrafluorobutane is also produced.

[0012] The by-product of the chlorination process, 1,1,2,3,4-pentachlorobutane, is produced by converting 1,3,4-trichloro-1-butene into chlorine (Cl ２ ) molecule is added to the starting material, 1,3-butadiene, to form 1,3,4-trichloro-1-butene. ２ After one molecule of chlorine (Cl) is added, hydrogen chloride (HCl) is released to form 1-chloro-1,3-butadiene. ２ Furthermore, 1,1,4-trichloro-2-butene, 1,1,2,4-tetrachloro-3-butene, etc. are also produced in the chlorination process, and it is believed that these various by-products are produced by the action of ionic and radical reactions.

[0013] Etching gas products used in semiconductor microfabrication require high purity. For this reason, the process for producing 1,2,3,4-tetrachlorohexafluorobutane, a raw material for synthesizing hexafluoro-1,3-butadiene, typically uses starting materials with as high purity as possible, and distillation is performed at each reaction step to remove by-products other than the target product. In this case, the by-products separated by distillation are treated as industrial waste.

[0014] The by-products 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene produced in the first chlorination step are chlorine gas (Cl ２ 1,1,2,3,4-Pentachlorobutane can be converted to 1,1,2,3,4-pentachlorobutane by reacting it with fluorine gas (F ２), it can be converted to 1,1,2,3,4-pentachloropentafluorobutane. Furthermore, 1,1,2,3,4-pentachloropentafluorobutane can be converted to the target product, 1,2,3,4-tetrachlorohexafluorobutane, by reacting it with chlorine monofluoride gas (ClF). 1,1,2,4-tetrachloro-3-butene, a by-product of the chlorination process other than the above, can be converted to chlorine gas (Cl ２ ) can be converted to 1,1,2,3,4,4-hexachlorobutane by reacting it with fluorine gas (F ２ ) can be converted to 1,1,2,3,4,4-hexachlorotetrafluorobutane by reacting it with chlorine monofluoride gas (ClF). Furthermore, 1,1,2,3,4,4-hexachlorotetrafluorobutane can be converted to the target product, 1,2,3,4-tetrachlorohexafluorobutane, via 1,1,2,3,4-pentachloropentafluorobutane, by reacting it with chlorine monofluoride gas (ClF). ２ In the reaction with 1,1,2,3,4-pentachloropentafluorobutane, some 1,1,2,3,4-pentachloropentafluorobutane is produced as a by-product, but as mentioned above, 1,1,2,3,4-pentachloropentafluorobutane can be converted to the target product, 1,2,3,4-tetrachlorohexafluorobutane, by reacting it with chlorine monofluoride gas (ClF). Furthermore, 1,1,2,3,4,4-hexachlorotetrafluorobutane can be produced by reacting 1,2,3,4-tetrachlorobutane with fluorine gas (F ２ In other words, the present invention makes it possible to produce 1,2,3,4-tetrachlorohexafluorobutane, a valuable material, using the by-products of the chlorination process and the fluorination process, which have conventionally been separated and then disposed of for a fee, thereby simultaneously realizing a reduction in the environmental load and an improvement in productivity.

[0015] Furthermore, the present inventors have reported that 1,3-butadiene and chlorine (Cl ２ ) to obtain 1,2,3,4-tetrachlorobutane, and 1,2,3,4-tetrachlorobutane and fluorine (F ２) to produce 1,2,3,4-tetrachlorohexafluorobutane, ２ and F ２ As a result of intensive investigations, the inventors have found that a liquid containing a series of by-products can be used in the fluorination step without purifying 1,2,3,4-tetrachlorobutane by distillation in the chlorination step. In other words, even if distillation equipment is omitted in the chlorination step, high-purity 1,2,3,4-tetrachlorohexafluorobutane can be obtained in the subsequent fluorination step using ordinary distillation equipment without adding excessive purification equipment. In the present invention, it has become possible to convert by-products that have been discarded up until now into the valuable material 1,2,3,4-tetrachlorohexafluorobutane. This is due to the advancement in understanding the structures of 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, 1,1,2,3,4-pentachlorobutane, and 1,1,2,4-tetrachloro-3-butene, which are by-products in the process of chlorinating 1,3-butadiene, and the development of Cl ２ , F ２ One reason for this is that by appropriately reacting ClF with fluorine, it is possible to derive valuable substances from each of these. Each step will be explained below.

[0016] (Step (a) A composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene and chlorine (Cl ２ In step (a), a composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene is contacted with chlorine (Cl ２) to obtain a composition containing 1,1,2,3,4-pentachlorobutane. Preferred reaction conditions in step (a) are, for example, as follows: Reaction temperature: preferably −20 to 40° C., more preferably −20 to 20° C. Reaction pressure: preferably 0 to 1.0 MPaG, more preferably 0 to 0.1 MPaG. Hereinafter, gauge pressure will be abbreviated as “MPaG.”

[0017] Reaction Solvent: Specific examples of preferred solvents include carbon tetrachloride, chloroform, dichloromethane, 1,2,3,4-tetrachlorobutane (dl), and 1,2,3,4-tetrachlorohexafluorobutane. When carbon tetrachloride, chloroform, or dichloromethane is used as the solvent, distillation is essential to separate the product from the solvent. 1,2,3,4-Tetrachlorobutane exists in dl and meso forms, with the dl form having a melting point of -10°C or less and a boiling point of 213°C, while the meso form has a melting point of 73°C and a boiling point of 218°C. Due to these differences in physical properties, the dl and meso forms can be separated. Furthermore, due to these physical properties, the dl form can be used as a solvent, but the meso form cannot. Using 1,2,3,4-tetrachlorobutane (dl) as the solvent has the advantage of eliminating the need to separate the product from the solvent. When 1,2,3,4-tetrachlorohexafluorobutane is used as a solvent, there is an advantage that it is not necessary to separate the product from the solvent in the subsequent fluorination reaction step. In addition, the reaction can be carried out without a solvent, and in this case, chlorine gas (Cl) can be efficiently separated compared to when a solvent is used. ２ ), but as the product concentration increases, the latter half of the reaction ２ In addition, the reactivity of 1,3-butadiene with chlorine (Cl) gas is reduced in order to react without a solvent. ２ It is necessary to separate the reaction solvent from the product 1,2,3,4-tetrachlorobutane by distillation in advance. ２ If 1,2,3,4-tetrachlorobutane (dl) or 1,2,3,4-tetrachlorohexafluorobutane is used as a reaction solvent in the previous step of reacting (a) with (b), the reaction crude liquid can be used as it is in step (a).

[0018] Raw material: The composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene used as a raw material is a mixture of 1,3-butadiene and chlorine (Cl ２ It is preferable to utilize by-products contained in the product of the reaction with 1,3-butadiene and chlorine (Cl). A composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene may further contain 1,1,2,4-tetrachloro-3-butene. ２) further contains 1,1,2,3,4-pentachlorobutane, and the production of 1,1,2,3,4-pentachlorobutane in step (a) increases the concentration of 1,1,2,3,4-pentachlorobutane in the reaction solution, thereby enabling effective utilization of the by-product. It is known that the 1,2,3,4-tetrachlorobutane produced by the reaction of butadiene with chlorine has a dl:meso ratio of about 1:3. When dl-1,2,3,4-tetrachlorobutane is used as a solvent, repeated use is desirable due to the production ratio issue. For this reason, it is desirable to separate the meso-1,2,3,4-tetrachlorobutane by crystallization, as described in the Examples below. When the dl-1,2,3,4-tetrachlorobutane obtained by this crystallization is repeatedly reused as a reaction solvent for butadiene and chlorine, 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, 1,1,2,3,4-pentachlorobutane, and 1,1,2,4-tetrachloro-3-butene accumulate. As described in the Examples below, the liquid in which these by-products have accumulated can be used as the raw material liquid for step (a), thereby efficiently obtaining the target product. When 1,1,2,4-tetrachloro-3-butene reacts with chlorine in step (a), it produces 1,1,2,3,4,4-hexachlorobutane. In the next step (b), 1,1,2,3,4,4-hexachlorobutane reacts with fluorine to produce 1,1,2,3,4,4-hexachlorotetrafluorobutane, and a portion of this reacts to produce 1,1,2,3,4-pentachloropentafluorobutane. The 1,1,2,3,4,4-hexachlorotetrafluorobutane and 1,1,2,3,4-pentachloropentafluorobutane produced here are further reacted with chlorine monofluoride in the next step (c), whereby 1,1,2,3,4,4-hexachlorotetrafluorobutane reacts preferentially to produce 1,1,2,3,4-pentachloropentafluorobutane, and then 1,1,2,3,4-pentachloropentafluorobutane reacts to produce the target 1,2,3,4-tetrachlorohexafluorobutane.On the other hand, if unreacted 1,1,2,4-tetrachloro-3-butene remains in step (a), 1,1,2,4-tetrachlorohexafluorobutane is produced in the subsequent step (b). 1,1,2,4-tetrachlorohexafluorobutane is a positional isomer of the target product 1,2,3,4-tetrachlorohexafluorobutane, and because their physical properties are similar, separation is difficult. For this reason, it is important to carry out the reaction in step (a) so as not to leave any unreacted 1,1,2,4-tetrachloro-3-butene. Furthermore, if 1,3,4-trichloro-1-butene or 1,1,4-trichloro-2-butene remains unreacted in step (a), trichloroheptafluorobutane is produced in step (b), but this can be easily separated by conventional distillation purification, taking advantage of the boiling point difference between 1,1,2,4-tetrachlorohexafluorobutane and the target product 1,2,3,4-tetrachlorohexafluorobutane. However, it is preferable to carry out the reaction in step (a) so as not to leave unreacted 1-chloro-1,3-butadiene and 1,3,4-trichloro-1-butene, as this improves the yield of the final target product.

[0019] Desirable reactor configuration: (i) Examples of materials for reactors such as reactor vessels and piping include stainless steel, alloys such as Inconel, Hastelloy, and Monel, glass, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), glass lining, PFA lining, and PTFE lining, but when the reaction is carried out at atmospheric pressure, a reactor vessel made of glass, PTFE, or PFA can be used.Preferably, a reactor made of glass, polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), glass lining, PFA lining, or PTFE lining is used, as there is no risk of metal chloride elution during repeated use.

[0020] (ii) Chlorine (Cl ２ The reaction of a composition containing at least one member selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene with chlorine gas (Cl ２It is preferable to carry out the reaction by contacting a liquid of a composition containing at least one member selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene with chlorine gas (Cl ) by bubbling or the like. ２ The amount of chlorine gas (Cl) introduced must be at least stoichiometric relative to the double bonds in the composition containing at least one member selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene. ２ The amount of chlorine gas (Cl) introduced is preferably 1.0 to 10.0 times the stoichiometric amount, more preferably 1.0 to 3.0 times the amount. ２ The use of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene can reduce the amount of unreacted chlorine gas (Cl ２ ) waste amount increases, which is not economical. ２ However, the introduction of the chlorine-removing agent increases the load of the process of degassing the dissolved chlorine from the reaction solution after the reaction is completed, and the equipment becomes larger. This is disadvantageous.

[0021] (iii) 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, and 1,1,2,4-tetrachloro-3-butene contain chlorine (Cl ２ ), so it is difficult to react with chlorine gas (Cl) by bubbling. ２ ) does not react immediately when it comes into contact with chlorine gas (Cl ２ ) at a flow rate exceeding the consumption rate of chlorine gas (Cl ２ ) is continuously introduced, the chlorine (Cl) dissolved in the reaction solution ２ ) is saturated and the unreacted chlorine (Cl ２ ) escapes into the gas phase and is wasted. Therefore, while checking the consumption of 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, and 1,1,2,4-tetrachloro-3-butene, chlorine gas (Cl ２ ) flow rate should be adjusted.

[0022] (iv) 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene and 1,1,2,4-tetrachloro-3-butene contain chlorine (Cl ２ ), therefore, in order to efficiently complete the reaction, it is effective to generate chlorine radicals by irradiating with light of a wavelength shorter than 480 nm (visible light to ultraviolet light (UV)). The light irradiation device may be installed inside or outside the reactor. When the light irradiation device is installed outside the reactor, the reactor may be provided with a window that transmits light and the reaction solution inside may be irradiated with light, or a pump circulation piping attached to the reactor may be provided with a window that transmits light and the reaction solution flowing inside the piping may be irradiated with light.

[0023] (Step (b) Mixing the composition containing 1,1,2,3,4-pentachlorobutane obtained in the step (a) with fluorine (F ２ In step (b), the composition containing 1,1,2,3,4-pentachlorobutane obtained in step (a) is contacted with fluorine (F ２ ) to obtain a composition containing 1,1,2,3,4-pentachloropentafluorobutane. Preferred reaction conditions in step (b) are, for example, as follows:

[0024] Reaction temperature: When the reaction temperature is low, fluorine gas (F ２ If the reaction temperature is too high, the utilization efficiency of the fluorination reaction product will decrease, and a decomposition reaction accompanied by cleavage of the C-C bond may occur, resulting in a decrease in the reaction yield. For these reasons, the reaction temperature is preferably set at 0 to 80°C, more preferably 0 to 40°C. Furthermore, since the reactivity decreases as the fluorination reaction progresses, the reaction temperature may be increased towards the latter half of the reaction.

[0025] Reaction pressure: Fluorine gas (F ２ Since the reaction is highly reactive, a high pressure is not preferable for the reaction to continue stably and continuously for a long period of time. Therefore, the pressure in the reactor is preferably set to a gauge pressure of -0.02 to 0.20 MPaG, more preferably -0.01 to 0.05 MPaG.

[0026] Fluorine gas (F ２ ) concentration: fluorine gas (F ２ ) is fluorine gas (F ２ Fluorine gas (F) may be introduced alone, or as a diluted mixed gas diluted with an inert gas such as nitrogen. ２ If the concentration of fluorine gas (F) is high, a decomposition reaction accompanied by cleavage of the C-C bond may occur, which will result in a decrease in the reaction yield. ２ It is advisable to adjust the concentration of fluorine gas (F ２ If the concentration of fluorine gas (F) is low, the production efficiency will decrease, which is industrially disadvantageous. ２ The concentration of the hydroxybenzoate is preferably adjusted to 20 to 80% by volume, more preferably 40 to 70% by volume.

[0027] Reaction solvent: Any known solvent that does not react with the raw materials can be used as the solvent, but specific examples of preferred solvents include tetrachloromethane, hexachloroethane, trichlorotrifluoroethane, tetrachlorodifluoroethane, and 1,2,3,4-tetrachlorohexafluorobutane (boiling point: 134°C). It is desirable to use the target product, 1,2,3,4-tetrachlorohexafluorobutane (boiling point: 134°C). This is because, since the target product is used as the solvent, the step of separating the solvent after the reaction can be omitted.

[0028] Raw material: The composition containing 1,1,2,3,4-pentachlorobutane obtained in the step (a) used as a raw material may also contain 1,1,2,3,4,4-hexachlorobutane. 1,1,2,3,4,4-Hexachlorobutane is produced from 1,1,2,4-tetrachloro-3-butene through the step (a) when the raw material used in the step (a) contains 1,1,2,4-tetrachloro-3-butene.

[0029] Desirable configuration of the reactor: Materials for the reactor, such as the reactor vessel and piping, include stainless steel, alloys such as Monel, Inconel, and Hastelloy, and nickel. ２A reactor made of PFA or PTFE can also be used, provided that the concentration of fluorine gas (F) is adjusted to 20% by volume or less and the reaction is carried out at atmospheric pressure. ２ The method of introducing fluorine gas (F) is to connect multiple reactors in series to introduce a composition containing 1,1,2,3,4-pentachlorobutane and fluorine gas (F ２ ) and the unreacted fluorine gas (F ２ ) into a reactor at a later stage, or by providing a stirring device in the reactor, ２ The utilization efficiency of fluorine (F ２ The crude 1,1,2,3,4-pentachloropentafluorobutane obtained by the reaction with 1,1,2,3,4-pentachloropentafluorobutane can be purified to a high degree by a general purification procedure such as distillation.

[0030] (Step (c) is a step of contacting the composition containing 1,1,2,3,4-pentachloropentafluorobutane obtained in step (b) with chlorine monofluoride (ClF) to obtain a composition containing 1,2,3,4-tetrachlorohexafluorobutane.) In step (c), the composition containing 1,1,2,3,4-pentachloropentafluorobutane obtained in step (b) is contacted with chlorine monofluoride (ClF) to obtain a composition containing 1,2,3,4-tetrachlorohexafluorobutane. Preferred reaction conditions in step (c) are, for example, as follows.

[0031] Reaction temperature: If the reaction temperature is low, the reactivity of chlorine monofluoride (ClF) decreases, and chlorine monofluoride (ClF) cannot be efficiently utilized in the reaction. On the other hand, if the reaction temperature is high, more energy is required, which is not economical. For these reasons, the reaction temperature is preferably 50°C to 180°C, more preferably 80°C to 150°C.

[0032] Reaction pressure: ClF gas is highly reactive, and high pressure is not preferable for stable, continuous reaction over a long period of time. Therefore, the pressure inside the reactor should be set to a gauge pressure of preferably -0.02 to 0.20 MPaG, more preferably 0 to 0.10 MPaG.

[0033] ClF gas concentration: The ClF gas used in the reaction may be ClF gas alone, or it may be introduced as a diluted mixed gas diluted with an inert gas such as nitrogen. When the ClF gas concentration is high and the flow rate is also high, localized overreaction occurs, producing trichloroheptafluorobutane and reducing the reaction selectivity. Furthermore, to ensure stable, continuous reaction over a long period of time, it is advisable to adjust the balance between the ClF gas concentration and flow rate to control reactivity. Furthermore, a low ClF gas concentration reduces production efficiency, which is industrially disadvantageous. Therefore, while the balance with the flow rate must be taken into consideration, the ClF gas concentration is preferably adjusted to 20 to 100% by volume, more preferably 60 to 100% by volume. ClF gas is introduced into the reactor at a flow rate of preferably 1 to 3,000 liters / hour (L / h), more preferably 1 to 1,500 L / h. For example, when a 2 L reactor is used on a laboratory scale, ClF gas is introduced at a flow rate of preferably 2 to 60 liters per hour (L / h), more preferably 6 to 40 L / h. When the reaction is carried out on an industrial scale, a large flow rate of 500 L / h or more is required, although this depends on the size of the reactor. Furthermore, as the reaction progresses, the concentration of 1,2,3,4-tetrachlorohexafluorobutane in the reaction solution increases, creating conditions that favor the production of excess reactants. Therefore, the flow rate and concentration of the ClF gas introduced may be adjusted as appropriate as the reaction progresses.

[0034] Reaction solvent: When the reaction is carried out in a liquid phase, it is desirable to use the target compound, 1,2,3,4-tetrachlorohexafluorobutane (boiling point: 134°C), as the solvent. The first reason is that since the target compound is used as the solvent, the step of separating the solvent after the reaction can be omitted. The second reason is that the fluorine (F ２ ) is also possible to use the target compound, 1,2,3,4-tetrachlorohexafluorobutane, as a reaction solvent. It is also possible to carry out the reaction without a solvent.

[0035] Raw material: The composition containing 1,1,2,3,4-pentachloropentafluorobutane obtained in the step (b) may also contain 1,1,2,3,4,4-hexachlorotetrafluorobutane. When 1,1,2,4-tetrachloro-3-butene is contained in the raw material used in the step (a), 1,1,2,3,4,4-hexachlorotetrafluorobutane is produced via the step (a) from 1,1,2,4-tetrachloro-3-butene to form 1,1,2,3,4,4-hexachlorobutane, and then via the step (b). 1,1,2,3,4,4-hexachlorotetrafluorobutane is also partially produced from 1,1,2,3,4-pentachlorobutane via a side reaction in the step (b).

[0036] Desirable Reactor Configuration: (i) Materials for the reactor, such as the reactor vessel and piping, include stainless steel, alloys such as Monel, Inconel, and Hastelloy, glass, nickel, polytetrafluoroethylene (PTFE), and perfluoroalkoxyalkane (PFA). When the reaction is carried out at atmospheric pressure, a glass reactor or a reactor made of PTFE or PFA can be used. (ii) Common methods for introducing ClF include a single-pipe system and an aeration plate system (sintered metal filter, PTFE filter). By reducing the bubble diameter, the contact efficiency between the gas and the liquid can be increased, thereby improving the utilization efficiency of ClF. Furthermore, the utilization efficiency of ClF can be improved by combining common methods, such as connecting multiple reactors in series to contact ClF gas with a composition containing 1,1,2,3,4-pentachloropentafluorobutane, and introducing some or all of the unreacted ClF gas discharged from the first reactor into the second reactor, or by installing a stirrer in the reactor. (iii) The reaction may be carried out batchwise or continuously. The batchwise method allows for easy reaction, while the continuous method allows for efficient reaction. (iv) The reaction liquid (crude 1,2,3,4-tetrachlorohexafluorobutane) obtained by reacting a composition containing 1,1,2,3,4-pentachloropentafluorobutane with chlorine monofluoride (ClF) can be highly purified by common purification procedures such as distillation. (v) By installing a condenser that re-liquefies the vapor of the reaction liquid downstream of the reactor, loss of the reaction liquid can be reduced and production efficiency can be increased. Furthermore, by taking advantage of the difference in boiling points between the raw material composition containing 1,1,2,3,4-pentachloropentafluorobutane and 1,2,3,4-tetrachlorohexafluorobutane, production efficiency can be increased by installing a device that liquefies and recovers 1,2,3,4-tetrachlorohexafluorobutane vapor downstream of the reactor.

[0037] Additives: Adding hydrogen fluoride (HF) improves the reactivity of chlorine monofluoride (ClF) and allows for efficient reaction. While the presence of HF in the reaction solution is essential, because the reaction solution is heated to a temperature above the boiling point of HF, it constantly evaporates and moves to the gas phase. Therefore, connecting a cooling condenser to the gas outlet of the reactor to condense the HF vapor and return it to the reaction solution can efficiently achieve the desired effect. Furthermore, since the effect decreases as HF evaporates and the HF concentration in the reaction solution decreases, it is preferable to introduce HF appropriately during the reaction. HF can be introduced continuously simultaneously with ClF. In this case, the amount of HF introduced relative to ClF is preferably adjusted to 0.001 to 0.200 times by mole, more preferably 0.001 to 0.160 times by mole, even more preferably 0.003 to 0.080 times by mole, and most preferably 0.003 to 0.040 times by mole. Other: The progress of the reaction can be monitored using common analytical equipment such as gas chromatography.

[0038] (Use of Inert Gas) Examples of the inert gas used in the present invention include nitrogen, helium, neon, argon, etc. The concentration of the inert gas is as described in the respective items above.

[0039] The present invention will be specifically described with reference to the following examples, but the scope of the present invention is not limited to the following examples. The following examples were carried out according to the reaction scheme of [Chemical Formula 1].

[0040] Example 1 (i) Chlorination reaction of 1,3-butadiene (C ４ H ６ + 2Cl ２ →C ４ H ６ Cl ４ A 4 L glass reactor equipped with a gas inlet and a gas outlet connected to a -20°C condenser was charged with chloroform (CHCl) as a reaction solvent. ３ 3000 g of 1,3-butadiene gas and chlorine gas (Cl ) were introduced into the reactor, and the reactor temperature was adjusted to 10° C. Then, in a light-shielded environment, 1,3-butadiene gas and chlorine gas (Cl ) were introduced into the reactor through the gas inlet while stirring with a magnetic stirrer. ２) were blown into the liquid phase at flow rates of 11.8 liters / hour (L / hr) and 24.0 L / hr, respectively, and the introduction of the gases was stopped after 9.5 hours. After stirring was continued for 1.0 hour, nitrogen gas was blown in through the gas inlet to remove chlorine gas (Cl ２ After the chloroform was removed, the reactor was opened and the reaction solution was taken out. Analysis of the reaction solution revealed that 1,2,3,4-tetrachlorobutane (C) was produced in an 87% yield (853 g). ４ H ６ Cl ４ ) was obtained as a by-product. ４ H ５ Cl ３ ), 1,1,4-trichloro-2-butene (C ４ H ５ Cl ３ ), 1,1,2,3,4-pentachlorobutane (C ４ H ５ Cl ５ ), 1,1,2,4-tetrachloro-3-butene (C ４ H ４ Cl ４ ) in total was 2.6% by weight (solvent CHCl ３ The total weight of the solution after the reaction (3967 g), including the weight of the reactant, was taken as 100% by weight. 3000 g of this reaction solution was used and subjected to distillation (packing: Helipak No. 2 / HETP: 39 mm, column height: 100 cm, number of theoretical plates: 25.6) to recover the solvent, and then 72 g of a low-boiling point fraction containing 53% by weight of 1,3,4-trichloro-1-butene, 23% by weight of 1,1,4-trichloro-2-butene, and 16% by weight of 1,2,3,4-tetrachlorobutane was obtained.

[0041] (ii) Chlorination reaction of 1,3,4-trichloro-1-butene and 1,1,4-trichloro-2-butene (C ４ H ５ Cl ３ +Cl ２ →C ４ H ５ Cl ５60 g of the low-boiling fraction obtained in Example 1(i) containing 53% by weight of 1,3,4-trichloro-1-butene, 23% by weight of 1,1,4-trichloro-2-butene, and 16% by weight of 1,2,3,4-tetrachlorobutane was placed in a 100 ml glass reactor equipped with a gas inlet and a gas outlet, and cooled to 0°C. Next, the fraction was heated in a natural light environment with 50% by volume chlorine gas (Cl) diluted with nitrogen. ２ ) was blown into the liquid phase at a flow rate of 2.0 liters / hour (L / hr), and the reaction was stopped after 10 hours of operation. Nitrogen gas was blown into the gas inlet to remove chlorine gas (Cl ２ After the chloroform (C) was removed, the reactor was opened and 78 g of the reaction solution was taken out. Analysis of this reaction solution revealed that the chloroform (C) was 1,1,2,3,4-pentachlorobutane (C ４ H ５ Cl ５ The 1,1,2,3,4-tetrachlorobutane concentration was 77% by weight, and the 1,2,3,4-tetrachlorobutane concentration was 12% by weight. The yield of 1,1,2,3,4-pentachlorobutane was 92% based on 1,3,4-trichloro-1-butene and 1,1,4-trichloro-2-butene. Note that 1,2,3,4-tetrachlorobutane did not react.

[0042] (iii) Fluorination reaction of 1,1,2,3,4-pentachlorobutane (C ４ H ５ Cl ５ +5F ２ →C ４ Cl ５ F ５ + 5HF) into a 200 ml PFA reactor equipped with a gas inlet and a gas outlet, 1,1,2,3,4-pentachlorobutane (C ４ H ５ Cl ５ 62 g of a reaction solution containing 77% by weight of fluorine gas (F) and 12% by weight of 1,2,3,4-tetrachlorobutane was added, and 145 g of a solvent, 1,2,3,4-tetrachlorohexafluorobutane, was added, and the mixture was cooled to 0°C. Next, 20% by volume of fluorine gas (F) diluted with nitrogen gas was added. ２ / N ２) was blown into the liquid phase at a flow rate of 14.8 liters / hour (L / hr), and the reaction was stopped after 26 hours of introduction. The temperature of the reactor was raised to 40°C, and nitrogen gas was blown in through the gas inlet to remove fluorine gas (F ２ After the solvent was removed, the reactor was opened and 208 g of the reaction liquid was taken out. Analysis of this reaction liquid revealed that the concentration of 1,1,2,3,4-pentachloropentafluorobutane was 29% by weight, and the concentration of 1,2,3,4-tetrachlorohexafluorobutane contained in the reaction liquid, including the amount added as a solvent, was 68% by weight. The yield of 1,1,2,3,4-pentachloropentafluorobutane, based on 1,1,2,3,4-pentachlorobutane, was 91%.

[0043] (iv) Cl-F exchange reaction of 1,1,2,3,4-pentachloropentafluorobutane (C ４ Cl ５ F ５ +ClF → C ４ Cl ４ F ６ +Cl ２ ) 200 g of the reaction solution containing 1,1,2,3,4-pentachloropentafluorobutane obtained in Example 1 (iii) at a concentration of 29 wt% was placed in a 200 ml PFA reactor equipped with a gas inlet and a gas outlet, a -20 ° C cooling condenser was connected to the gas outlet side of the reactor, and the reactor was heated to 130 ° C. Next, 50 vol% chlorine monofluoride gas (ClF) diluted with nitrogen was blown in at a flow rate of 2.4 liters / hour (L / hr), and the reaction was stopped after 5.5 hours of introduction. Nitrogen gas was blown in through the gas inlet to expel the chlorine monofluoride gas (ClF) dissolved in the reaction solution, and then the reactor was opened and 194 g of the reaction solution was removed. Analysis of this reaction solution revealed that the concentration of 1,2,3,4-tetrachlorohexafluorobutane was 96 wt%. The yield of 1,2,3,4-tetrachlorohexafluorobutane was 90% based on 1,1,2,3,4-pentachloropentafluorobutane. By using the present invention, by-products from each process that had been discarded as industrial waste were converted into the target product, and the yield of 1,2,3,4-tetrachlorohexafluorobutane increased by approximately 16% compared to when the present invention was not applied.

[0044] Example 2 (i) Chlorination reaction of 1,3,4-trichloro-1-butene and 1,1,4-trichloro-2-butene (C ４ H ５ Cl ３ +Cl ２ →C ４ H ５ Cl ５ 60 g of a low-boiling point fraction containing 53% by weight of 1,3,4-trichloro-1-butene, 23% by weight of 1,1,4-trichloro-2-butene, and 16% by weight of 1,2,3,4-tetrachlorobutane, obtained by the same procedure as in Example 1(i), was placed in a 100 ml glass reactor equipped with a gas inlet and a gas outlet, and cooled to 0°C. Next, in a light-shielded environment, the fraction was diluted with 50% by volume of chlorine gas (Cl ２ ) was blown into the liquid phase at a flow rate of 2.0 liters / hour (L / hr), and the reaction was stopped after 10 hours of operation. Nitrogen gas was blown into the gas inlet to remove chlorine (Cl ) dissolved in the reaction solution. ２ ) was removed, the reactor was opened, and 71 g of the reaction liquid was taken out. Analysis of this reaction liquid showed that the concentration of 1,1,2,3,4-pentachlorobutane was 55% by weight and the concentration of 1,2,3,4-tetrachlorobutane was 13% by weight. In addition, the concentration of unreacted 1,3,4-trichloro-1-butene was 14% by weight and the concentration of 1,1,4-trichloro-2-butene was 11% by weight. In addition, the yield of 1,1,2,3,4-pentachlorobutane was 60% based on 1,3,4-trichloro-1-butene and 1,1,4-trichloro-2-butene. Note that 1,2,3,4-tetrachlorobutane had not reacted.

[0045] (ii) Fluorination reaction of 1,1,2,3,4-pentachlorobutane (C ４ H ５ Cl ５ +5F ２ →C ４ Cl ５ F ５+ 5HF) 64 g of the reaction liquid containing 1,1,2,3,4-pentachlorobutane at a concentration of 55 wt % and 1,2,3,4-tetrachlorobutane at a concentration of 13 wt %, obtained by the procedure of Example 2(i), was placed in a 200 ml PFA reactor equipped with a gas inlet and a gas outlet, and 150 g of 1,2,3,4-tetrachlorohexafluorobutane solvent was added, followed by cooling to 0°C. Next, 20% by volume fluorine gas (F ２ / N ２ ) was blown into the liquid phase at a flow rate of 14.8 liters / hour (L / hr), and the reaction was stopped after 31 hours of introduction. The temperature of the reactor was raised to 40°C, and nitrogen gas was blown in through the gas inlet to remove fluorine gas (F ２ After the solvent was removed, the reactor was opened and 214 g of the reaction liquid was removed. Analysis of this reaction liquid revealed that the 1,1,2,3,4-pentachloropentafluorobutane concentration was 20 wt %, and the concentration of 1,2,3,4-tetrachlorohexafluorobutane contained in the reaction liquid, including the amount added as a solvent, was 71 wt %. Furthermore, the yield of 1,1,2,3,4-pentachloropentafluorobutane was 90% based on 1,1,2,3,4-pentachlorobutane. According to the present invention, by-products from each process that had been discarded as industrial waste were converted into the target product, and the yield of 1,2,3,4-tetrachlorohexafluorobutane increased by approximately 11% compared to when the present invention was not applied.

[0046] Example 3 is an example demonstrating the conversion of 1,1,2,4-tetrachloro-3-butene to the target product, 1,2,3,4-tetrachlorohexafluorobutane, via 1,1,2,3,4,4-hexachlorobutane, 1,1,2,3,4,4-hexachlorotetrafluorobutane, and 1,1,2,3,4-pentachloropentafluorobutane. The production rate of 1,1,2,4-tetrachloro-3-butene is low in a one-pass reaction. Therefore, a series of reactions was performed by repeatedly using a solvent to accumulate the solvent in a concentration sufficient to demonstrate the process of conversion to the target product, 1,2,3,4-tetrachlorohexafluorobutane, via 1,1,2,3,4,4-hexachlorobutane, 1,1,2,3,4,4-hexachlorotetrafluorobutane, and 1,1,2,3,4-pentachloropentafluorobutane.

[0047] (i) Chlorination reaction of 1,3-butadiene (C ４ H ６ + 2Cl ２ →C ４ H ６ Cl ４ 1,600 g of dl-1,2,3,4-tetrachlorobutane as a reaction solvent was placed in a 3 L glass reactor equipped with a gas inlet and a gas outlet connected to a -20°C condenser, and the reactor temperature was adjusted to 10°C. Next, in a light-shielded environment, 1,3-butadiene gas, chlorine gas (Cl), and the like were introduced into the gas inlet while stirring with a magnetic stirrer. ２ ) were blown into the liquid phase at flow rates of 11.8 liters / hour (L / hr) and 24.0 L / hr, respectively, and the introduction of the gas was stopped after 9.5 hours. After stirring was continued for 1.0 hour, nitrogen gas was blown in through the gas inlet to remove chlorine (Cl ) dissolved in the reaction liquid. ２ After the 1,2,3,4-tetrachlorobutane added as a solvent was removed, the reactor was opened and the reaction solution was taken out. Analysis of the reaction solution revealed that the 1,2,3,4-tetrachlorobutane (C) was extracted in an 82% yield (799 g). ４ H ６ Cl ４) was obtained. This reaction solution was cooled to -5°C to precipitate meso-1,2,3,4-tetrachlorobutane, and the solid and liquid were separated by centrifugation. The obtained solid was meso-1,2,3,4-tetrachlorobutane with a purity of 97.9% by weight. On the other hand, the separated liquid contained, in addition to the main component 1,2,3,4-tetrachlorobutane, 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, 1,1,2,3,4-pentachlorobutane, and 1,1,2,4-tetrachloro-3-butene as by-products. This separated liquid was recovered and used as the reaction solvent in a similar reaction, three times in total. The composition of the separated liquid after the third reaction was analyzed to find that the concentration of dl-1,2,3,4-tetrachlorobutane was 77.2% by weight, the concentration of meso-1,2,3,4-tetrachlorobutane was 5.3% by weight, the concentration of 1,3,4-trichloro-1-butene was 7.7% by weight, the concentration of 1,1,4-trichloro-2-butene was 3.2% by weight, the concentration of 1,1,2,3,4-pentachlorobutane was 4.0% by weight, and the concentration of 1,1,2,4-tetrachloro-3-butene was 2.6% by weight. This separated liquid was recovered as a solvent and used in the subsequent chlorination reaction of 1,3-butadiene.

[0048] (ii) Chlorination reaction of 1,3-butadiene (C ４ H ６ + 2Cl ２ →C ４ H ６ Cl ４ 1,600 g of the recovered solvent obtained in Example 3(i) was introduced as a reaction solvent into a 3 L glass reactor equipped with a gas inlet and a gas outlet connected to a -20°C condenser, and the reactor temperature was adjusted to 10°C. Next, in a light-shielded environment, 1,3-butadiene gas, chlorine gas (Cl ), and the like were introduced into the reactor through the gas inlet while stirring with a magnetic stirrer. ２ ) were blown into the liquid phase at flow rates of 11.8 liters / hour (L / hr) and 24.0 L / hr, respectively, and the introduction of the gas was stopped after 9.5 hours. After stirring was continued for 1.0 hour, nitrogen gas was blown in through the gas inlet to remove chlorine (Cl ) dissolved in the reaction liquid. ２After the solvent was removed, the reactor was opened and the reaction solution was removed. Analysis of the reaction solution showed that 1,2,3,4-tetrachlorobutane was obtained in an 80% yield (780 g yield) after subtracting the 1,2,3,4-tetrachlorobutane added as a solvent. The reaction solution was cooled to -5°C to precipitate meso-1,2,3,4-tetrachlorobutane, and the solid and liquid were separated by centrifugation. The obtained solid was meso-1,2,3,4-tetrachlorobutane with a purity of 98.2% by weight. On the other hand, the composition of the separated liquid was analyzed, and as a result, the concentration of dl-1,2,3,4-tetrachlorobutane was 71.7% by weight, the concentration of meso-1,2,3,4-tetrachlorobutane was 5.3% by weight, the concentration of 1,3,4-trichloro-1-butene was 9.7% by weight, the concentration of 1,1,4-trichloro-2-butene was 4.1% by weight, the concentration of 1,1,2,3,4-pentachlorobutane was 5.3% by weight, and the concentration of 1,1,2,4-tetrachloro-3-butene was 3.1% by weight.

[0049] (iii) Chlorination reaction of 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, and 1,1,2,4-tetrachloro-3-butene (C ４ H ５ Cl ３ +Cl ２ →C ４ H ５ Cl ５ / C ４ H ４ Cl ４ +Cl ２ →C ４ H ４ Cl ６ 1900 g of the separated liquid obtained in Example 3(ii) containing 71.7% by weight of dl-1,2,3,4-tetrachlorobutane, 5.3% by weight of meso-1,2,3,4-tetrachlorobutane, 9.7% by weight of 1,3,4-trichloro-1-butene, 4.1% by weight of 1,1,4-trichloro-2-butene, 5.3% by weight of 1,1,2,3,4-pentachlorobutane, and 3.1% by weight of 1,1,2,4-tetrachloro-3-butene was introduced into a 3 L glass reactor equipped with a gas inlet and a gas outlet, and the separated liquid was heated to 20°C. Next, the separated liquid was irradiated with UV light having a wavelength of 385 nm using an LED-type UV irradiation device, and 50% by volume of chlorine gas (Cl) diluted with nitrogen was added.２ ) was blown into the liquid phase at a flow rate of 25.0 liters / hour (L / hr), and after 6.5 hours of introduction, chlorine gas (Cl ２ The introduction of chlorine (Cl) was stopped. Stirring was continued for another 2 hours, and then the UV irradiation was stopped. Nitrogen gas was then blown in through the gas inlet to remove chlorine (Cl) dissolved in the reaction solution. ２ ), the reactor was opened, and 1988 g of reaction liquid was withdrawn. Analysis of this reaction liquid showed that the concentration of dl-1,2,3,4-tetrachlorobutane was 67.2% by weight, the concentration of meso-1,2,3,4-tetrachlorobutane was 5.1% by weight, the concentration of 1,3,4-trichloro-1-butene was 0.2% by weight, the concentration of 1,1,4-trichloro-2-butene was 0.1% by weight, the concentration of 1,1,2,3,4-pentachlorobutane was 22.6% by weight, the concentration of 1,1,2,4-tetrachloro-3-butene was 0% by weight, and the concentration of 1,1,2,3,4,4-hexachlorobutane was 4.0% by weight. The yield of 1,1,2,3,4-pentachlorobutane based on 1,3,4-trichloro-1-butene and 1,1,4-trichloro-2-butene was 92%. The yield of 1,1,2,3,4,4-hexachlorobutane was 99% based on 1,1,2,4-tetrachloro-3-butene.

[0050] (iv) Fluorination reaction of 1,1,2,3,4-pentachlorobutane and 1,1,2,3,4,4-hexachlorobutane (C ４ H ５ Cl ５ +5F ２ →C ４ Cl ５ F ５ +5HF, C ４ H ４ Cl ６ +4F ２ →C ４ Cl ６ F ４+4HF) 8L with a gas inlet and outlet, and a jacket with cooling water flow A vertical SUS reactor was charged with 1,800 g of the reaction solution obtained by the procedure of Example 3(iii), which contained 67.2% by weight of dl-1,2,3,4-tetrachlorobutane, 5.1% by weight of meso-1,2,3,4-tetrachlorobutane, 0.2% by weight of 1,3,4-trichloro-1-butene, 0.1% by weight of 1,1,4-trichloro-2-butene, 22.6% by weight of 1,1,2,3,4-pentachlorobutane, 0% by weight of 1,1,2,4-tetrachloro-3-butene, and 4.0% by weight of 1,1,2,3,4,4-hexachlorobutane, and 4,200 g of 1,2,3,4-tetrachlorohexafluorobutane as a solvent. A -20°C cooling condenser was connected to the gas outlet side of the reactor, and the reactor was cooled to 10°C. Next, 20% by volume fluorine gas (F ２ / N ２ ) was blown into the liquid phase at a flow rate of 444 liters / hour (L / hr) and introduced for 12 hours. ２ / N ２ The reaction was continued for 4 hours with the concentration of fluorine (F) adjusted to 33% by volume and the flow rate adjusted to 538 L / hr. After the reaction was stopped, the temperature of the reactor was raised to 40°C, and nitrogen gas was blown in through the gas inlet to remove fluorine gas (F) dissolved in the reaction solution. ２), the reactor was opened and 6,822 g of reaction liquid was removed. Analysis of this reaction liquid revealed that the 1,1,2,3,4-pentachloropentafluorobutane concentration was 10.4% by weight, the 1,1,2,3,4,4-hexachlorotetrafluorobutane concentration was 1.4% by weight, and the concentration of 1,2,3,4-tetrachlorohexafluorobutane contained in the reaction liquid, including the amount added as a solvent, was 85.7% by weight. The yield of 1,1,2,3,4-pentachloropentafluorobutane, based on 1,1,2,3,4-pentachlorobutane, was 125%. The yield of 1,1,2,3,4-pentachloropentafluorobutane exceeded 100% because 1,1,2,3,4-pentachloropentafluorobutane is produced not only from 1,1,2,3,4-pentachlorobutane but also from 1,2,3,4-tetrachlorobutane and 1,1,2,3,4,4-hexachlorobutane as a side reaction. The yield of 1,1,2,3,4,4-hexachlorotetrafluorobutane was 104% based on 1,1,2,3,4,4-hexachlorobutane. The yield of 1,1,2,3,4,4-hexachlorotetrafluorobutane exceeded 100% because 1,1,2,3,4,4-hexachlorotetrafluorobutane includes 1,1,2,3,4,4-hexachlorotetrafluorobutane produced from 1,1,2,3,4,4-hexachlorobutane as well as 1,2,3,4-tetrachlorobutane and 1,1,2,3,4-pentachlorobutane as a side reaction.

[0051] (v) Cl-F exchange reaction of 1,1,2,3,4-pentachloropentafluorobutane and 1,1,2,3,4,4-hexachlorotetrafluorobutane (C ４ Cl ５ F ５ +ClF → C ４ Cl ４ F ６ +Cl ２ , C ４ Cl ６ F ４ +2ClF → C ４ Cl ４ F ６ + 2Cl ２) 2000 g of a reaction solution containing 1,1,2,3,4-pentachloropentafluorobutane and 1,1,2,3,4,4-hexachlorotetrafluorobutane obtained in Example 3(iv) at concentrations of 10.4 wt% and 1.4 wt%, respectively, and 85.7 wt% including the amount of 1,2,3,4-tetrachlorohexafluorobutane added as a solvent, was charged into a 2-L vertical SUS reactor equipped with a gas inlet and a gas outlet, and the reaction solution was heated to 110°C. A -30°C cooling condenser was connected to the gas outlet side of the reactor, and the reactor was heated to 110°C. Next, chlorine monofluoride gas (ClF) was introduced at a flow rate of 11.5 liters / hour (L / hr) for 10 minutes. Heating of the reactor was stopped, and nitrogen gas was blown in through the gas inlet to expel the chlorine monofluoride gas (ClF) dissolved in the reaction solution, and the reaction solution was then sampled. Analysis of this reaction solution revealed that the 1,1,2,3,4-pentachloropentafluorobutane concentration was 10.8 wt % and the 1,1,2,3,4,4-hexachlorotetrafluorobutane concentration was 0.4 wt %. The reactor was again heated to 110°C, and chlorine monofluoride gas (ClF) was blown in at a flow rate of 11.5 L / hr for 140 minutes, after which the reaction was stopped. Heating of the reactor was stopped, and nitrogen gas was blown in through the gas inlet to expel chlorine monofluoride gas (ClF) dissolved in the reaction solution, after which the reactor was opened and 1,960 g of the reaction solution was taken out. Analysis of this reaction solution revealed that the 1,1,2,3,4-pentachloropentafluorobutane concentration was 1.4 wt %, the 1,1,2,3,4,4-hexachlorotetrafluorobutane concentration was 0 wt %, and the concentration of 1,2,3,4-tetrachlorohexafluorobutane in the reaction solution, including the amount added as a solvent, was 96.5 wt %. The yield of 1,2,3,4-tetrachlorohexafluorobutane was 90% based on 1,1,2,3,4-pentachloropentafluorobutane. The ClF utilization rate (= ClF reaction consumption / ClF introduced × 100) was 57%. By using the present invention, by-products from each process that had been discarded as industrial waste were converted into the target product, and the yield of 1,2,3,4-tetrachlorohexafluorobutane increased by approximately 23% compared to when the present invention was not applied.

[0052] Example 4 Cl-F exchange reaction of 1,1,2,3,4-pentachloropentafluorobutane and 1,1,2,3,4,4-hexachlorotetrafluorobutane (C ４ Cl ５ F ５ +ClF → C ４ Cl ４ F ６ +Cl ２ , C ４ Cl ６ F ４ +2ClF → C ４ Cl ４ F ６ + 2Cl ２) The reaction conditions for the Cl-F exchange reaction described in Example 3 were the same as those in Example 3, except for the ClF gas introduction time and the addition of hydrogen fluoride (HF). Hydrogen fluoride was added by mixing it with chlorine monofluoride gas (ClF) and continuously introducing it. A mixed gas consisting of 97% by volume chlorine monofluoride gas (ClF) and 3% by volume hydrogen fluoride gas was blown in at a flow rate of 11.9 liters / hour (L / hr) for 10 minutes. Heating of the reactor was stopped, and nitrogen gas was blown in through the gas inlet to expel chlorine monofluoride gas (ClF) dissolved in the reaction solution, after which the reaction solution was sampled. Analysis of this reaction solution revealed that the 1,1,2,3,4-pentachloropentafluorobutane concentration was 11.2% by weight and the 1,1,2,3,4,4-hexachlorotetrafluorobutane concentration was 0.1% by weight. The reactor was again heated to 110 ° C., and a mixed gas consisting of 97% by volume chlorine monofluoride gas (ClF) and 3% by volume hydrogen fluoride (HF) gas was blown in at a flow rate of 11.9 L / hr, and after 120 minutes of introduction, the reaction was stopped. Heating of the reactor was stopped, and nitrogen gas was blown in through the gas inlet to expel the chlorine monofluoride gas (ClF) dissolved in the reaction solution, and then the reactor was opened and 1965 g of reaction solution was taken out. Analysis of this reaction solution showed that the 1,1,2,3,4-pentachloropentafluorobutane concentration was 1.0 wt%, the 1,1,2,3,4,4-hexachlorotetrafluorobutane concentration was 0 wt%, and the concentration of 1,2,3,4-tetrachlorohexafluorobutane contained in the reaction solution was 96.7 wt%, including the amount added as a solvent. The yield of 1,2,3,4-tetrachlorohexafluorobutane was 94% based on 1,1,2,3,4-pentachloropentafluorobutane. The ClF utilization rate (= ClF reaction consumption / ClF introduction amount × 100) was 68%. By using the present invention, by-products from each process that had been discarded as industrial waste were converted into the target product, and the yield of 1,2,3,4-tetrachlorohexafluorobutane increased by approximately 24% compared to when the present invention was not applied.

[0053] Example 5 Chlorination of 1,3-butadiene (C ４ H ６ + 2Cl ２ →C ４ H ６ Cl４ 3,000 g of chloroform was introduced as a reaction solvent into a 4 L glass reactor equipped with a gas inlet and a gas outlet connected to a -20°C condenser, and the reactor temperature was adjusted to 0°C. Next, in a light-shielded environment, 1,3-butadiene gas, chlorine gas (Cl), and the like were introduced into the reactor through the gas inlet while stirring with a magnetic stirrer. ２ ) were blown into the liquid phase at flow rates of 11.8 liters / hour (L / hr) and 11.8 L / hr, respectively, and the reaction was stopped after 9.5 hours, and a portion of the reaction liquid was sampled. Analysis of the sampled reaction liquid revealed that 1-chloro-1,3-butadiene (C ４ H ５ It was then confirmed that chlorine gas (Cl) was produced as a by-product. ２ ) was blown into the liquid phase at a flow rate of 11.8 L / hr, and the reaction was stopped after 9.5 hours. Nitrogen gas was blown into the gas inlet to remove chlorine (Cl ２ After the benzene was removed, the reactor was opened and the reaction solution was taken out. Analysis of the reaction solution showed that 1,2,3,4-tetrachlorobutane was obtained in a yield of 83% (yield of 824 g). In addition, by-products such as 1,3,4-trichloro-1-butene, 1,1,4-trichloro-2-butene, 1,1,2,3,4-pentachlorobutane, and 1,1,2,4-tetrachloro-3-butene were present in an amount of 1.8 wt%, 0.7 wt%, 0.9 wt%, and 0.2 wt%, respectively (solvent: CHCl 3 ). ３ The weight of the entire solution after the reaction, including the weight of the chloro-1,3-butadiene, was taken as 100% by weight. ) was contained. Furthermore, 1-chloro-1,3-butadiene was consumed in the reaction and was not contained in the solution after completion of the reaction. Example 5 revealed that in the chlorination reaction of 1,3-butadiene, 1-chloro-1,3-butadiene is produced during the reaction, and when further chlorinated, it is chlorinated to 1,3,4-trichloro-1-butene and 1,1,2,3,4-pentachlorobutane.

[0054] In a method for producing 1,2,3,4-tetrachlorohexafluorobutane using 1,3-butadiene as a starting material, by converting by-products and the like produced by the chlorination reaction of 1,3-butadiene into a valuable substance, 1,2,3,4-tetrachlorohexafluorobutane, it is possible to increase the productivity of 1,2,3,4-tetrachlorohexafluorobutane.

Claims

1. A method for producing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane, comprising: (a) contacting a composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene with chlorine (Cl ２ ), to obtain a composition containing 1,1,2,3,4-pentachlorobutane; and (b) contacting the composition containing 1,1,2,3,4-pentachlorobutane obtained in the step (a) with fluorine (F ２ ), to obtain a composition containing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane.

2. The method according to claim 1, wherein the composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene in the step (a) contains the product in the reaction of 1,3-butadiene and chlorine (Cl ２ ).

3. In the reaction of 1,3-butadiene with chlorine (Cl ２ ), the product further contains 1,1,2,3,4-pentachlorobutane, and the concentration of 1,1,2,3,4-pentachlorobutane in the reaction solution is increased by the production of 1,1,2,3,4-pentachlorobutane in the step (a). The method according to claim 2.

4. The method according to claim 2 or 3, wherein the product in the reaction of 1,3-butadiene and chlorine (Cl ２ ), further comprises 1,1,2,4-tetrachloro-3-butene.

5. The method according to any one of claims 1 to 3, wherein UV irradiation is performed in the step (a).

6. A method for producing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane, comprising: (a) contacting a composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene with chlorine (Cl ２ ), to obtain a composition containing 1,1,2,3,4-pentachlorobutane; (b) contacting the composition containing 1,1,2,3,4-pentachlorobutane obtained in the step (a) with fluorine (F ２ ), to obtain a composition containing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane; and (c) contacting the composition containing 1,1,2,3,4-pentachloro-1,2,3,4,4-pentafluorobutane obtained in the step (b) with chlorine monofluoride (ClF), to obtain a composition containing 1,2,3,4-tetrachloro-1,1,2,3,4,4-hexafluorobutane.

7. A composition containing at least one selected from the group consisting of 1-chloro-1,3-butadiene, 1,3,4-trichloro-1-butene, and 1,1,4-trichloro-2-butene in the step (a) is a product in the reaction of 1,3-butadiene and chlorine (Cl ２ ), and the method according to claim 6.

8. In the reaction of 1,3-butadiene with chlorine (Cl ２ ), the product further contains 1,1,2,3,4-pentachlorobutane, and the concentration of 1,1,2,3,4-pentachlorobutane in the reaction solution is increased by the production of 1,1,2,3,4-pentachlorobutane by the step (a). The method according to claim 7.

9. In the reaction of 1,3-butadiene with chlorine (Cl ２ ), the method according to claim 7 or 8, wherein the product further comprises 1,1,2,4-tetrachloro-3-butene.

10. The method according to any one of claims 6 to 8, wherein UV irradiation is performed in the step (a).

Images