JP5609043B2 - Fine particle size anion exchange resin, method for producing the same, and method for producing dichlorobutene using the same - Google Patents

Description

  The present invention relates to the production of dichlorobutene by reacting 1,3-butadiene with chlorine at a low temperature of 20 to 70 ° C. in a solvent to produce 3,4-dichloro-1-butene and 1,4-dichloro-2-butene. The present invention relates to a fine particle size anion exchange resin as a catalyst that can be suitably used in the method, a method for producing the same, and a method for producing dichlorobutene using the same.

  In commercial scale plants, 3,4-dichloro-1-butene and 1,4-dichloro-2-butene are produced by contacting a large excess of butadiene and chlorine by a gas phase reaction at 220-300 ° C. . In this method, the yield is as low as about 90%, and a large amount of waste is generated. 3,4-dichloro-1-butene is a raw material for producing a chloroprene monomer by dehydrochlorination reaction. The production ratio of 3,4-dichloro-1-butene in dichlorobutene produced by this gas phase reaction is 35. 1,4-dichloro-2-butene produced mainly (about 65%) needs to be converted to 3,4-dichloro-1-butene by isomerization.

  In order to solve the above problems, a method for chlorinating 1,3-butadiene at a low temperature in the liquid phase has been studied. For example, in Patent Document 1, carbon tetrachloride is mainly used as a reaction solvent, and the liquid phase chlorination reaction of 1,3-butadiene is examined in detail, and reaction conditions, catalyst types, catalyst concentrations, and other reaction conditions are examined. The basic matters are elucidated.

  Further, Patent Document 2 uses a solvent having a boiling point of −15 to 40 ° C. at normal pressure, reacts while removing heat generated by the reaction by volatilization of the solvent and unreacted 1,3-butadiene, and the bottom of the reactor. A method for taking out the reaction solution more is disclosed. In this method, chlorofluorocarbons that do not substantially react with chlorine gas, or n-butane or pentane is used as a solvent, and 3,4-dichloro-1-butene and 1,4-dichloro are present in the presence of a pyridine catalyst. -2-butene can be produced in high yield. In this method, the production ratio of 3,4-dichloro-1-butene in the produced dichlorobutene is as high as 48 to 55%, and in producing chloroprene monomer, 1,4-dichloro-2-butene is obtained by isomerization. This is advantageous because the effort to convert to 3,4-dichloro-1-butene is reduced.

British Patent No. 1435826 US Pat. No. 5,077,443

  However, in Patent Document 1, carbon tetrachloride, which is currently difficult to use, is used as a solvent. Further, chlorofluorocarbons used in the method described in Patent Document 2 are ozone layers such as 1,2-dichlorotetrafluoroethane (boiling point 4 ° C.) and 1,1-dichloro-1-fluoroethane (boiling point 32 ° C.). It is a specific chlorofluorocarbon with a large destruction coefficient and is difficult to use at present. On the other hand, hydrocarbons such as n-butane and pentane are also used, but these are susceptible to chlorination and have a large solvent loss. Furthermore, the concentration of total dichlorobutene in the reaction mixture obtained from the bottom of the reactor in this manner is the same as in Example 1 and Examples 5-15 using 1,2-dichlorotetrafluoroethane as solvent. Since the butene weight ratio is 6 to 10 (molar ratio 4.4 to 7.3), the heat energy consumption in the solvent separation process is large. In addition, when the catalyst used in the methods described in Patent Document 1 and Patent Document 2 is used, the metal material is severely corroded, so that it is difficult to use a general-purpose material metal.

  An object of the present invention is to provide a method for obtaining a reaction liquid having a high dichlorobutene concentration with a high yield of dichlorobutene and requiring less energy for solvent separation in a subsequent step, using an apparatus composed of a general-purpose material metal. Is to provide. Another object of the present invention is to provide a method for producing 3,4-dichloro-1-butene, which is a raw material of chloroprene monomer, with higher selectivity. Furthermore, the objective of this invention is providing the anion exchange resin used for those methods.

  As a result of intensive studies to solve the above problems, the present inventors have used a specific fine particle size anion exchange resin as a catalyst, and a liquid phase chlorination method of 1,3-butadiene under a predetermined condition. In this case, dichlorobutene can be obtained in a high concentration with a high yield that requires less energy for solvent separation in the subsequent process, and with higher selectivity, using an apparatus composed of general-purpose material metals. The inventors have found that 3,4-dichloro-1-butene, which is a raw material for the chloroprene monomer, can be obtained, and have completed the present invention. That is, the present invention relates to dichloro which reacts 1,3-butadiene with chlorine at a reaction temperature of 20 to 70 ° C. in a solvent to produce 3,4-dichloro-1-butene and 1,4-dichloro-2-butene. A fine particle size anion exchange resin as a catalyst used in a method for producing butene, wherein the average particle size is 0.5 to 10 μm, a production method thereof, and This is a method for producing dichlorobutene using the same.

  Hereinafter, the present invention will be described in detail.

  The fine particle size anion exchange resin of the present invention reacts 1,3-butadiene with chlorine at a reaction temperature of 20 to 70 ° C. in a solvent to produce 3,4-dichloro-1-butene and 1,4-dichloro-2. -A catalyst used in a process for producing dichlorobutene for producing butene, having an average particle size of 0.5 to 10 µm.

  In the process for producing dichlorobutene by liquid phase chlorination of 1,3-butadiene using a catalyst, the polarization of chlorine is promoted by the catalyst, and the chlorine addition reaction to 1,3-butadiene proceeds by an ionic mechanism, and the radical mechanism. It is believed that advantageous effects such as a high yield and a high production ratio of 3,4-dichloro-1-butene can be obtained as compared with a gas phase high temperature method in which the reaction proceeds at a high temperature. The use of an anion exchange resin as a catalyst is advantageous because the reaction proceeds by an ionic mechanism, and the metal material corrosion of the device, which is a problem in the prior art, can be effectively suppressed. However, the catalytic reaction occurs on the surface of the anion exchange resin. Therefore, in order to obtain a sufficient catalytic effect, it is necessary to exist in the reaction system with a certain surface area or more. Since commercially available anion exchange resins are beads having a particle size of 0.3 to 1.25 mm, the surface area per unit catalyst amount is small, a large amount of catalyst is required, and the apparatus becomes very large. Absent. If a commercially available resin is used after being pulverized, a small amount of catalyst is required. However, the catalyst is easily destroyed, and irregular fine particles are generated, cake resistance increases, and filtration separation from the reaction solution becomes difficult. These problems can be solved by making the anion exchange resin into small-diameter beads. The smaller the particle size, the larger the surface area per unit catalyst amount, which is advantageous. However, when the particle size is too small, separation from the reaction solution becomes difficult. Therefore, in order for the resin of the present invention to obtain advantageous effects, the average particle size needs to be 0.5 to 10 μm, preferably 1 to 5 μm, and more preferably 1 to 3 μm. When the average particle size is less than 0.5 μm, the cake resistance is large and difficult to separate from the reaction solution by filtration, and when it exceeds 10 μm, the particles are easily broken, and irregular fine particles are generated. The cake resistance increases and it becomes difficult to separate the reaction liquid from the filter.

  The fine particle size anion exchange resin of the present invention is obtained by so-called seed polymerization in which polymer particles having an average particle size of 0.3 to 2 μm produced by emulsion polymerization are used as seeds and a monomer containing a crosslinking agent is absorbed and polymerized. Appearance and polymer that are fine particle size beads having an average particle size of 0.5 to 10 μm made from a copolymer, have a small particle size variation, and have an IPN (interpenetrating polymer network) structure in which polymer molecular chains are intertwined Has structural features. With these features, the following advantageous effects can be obtained in terms of performance as a catalyst. 1) A large specific surface area and a small amount of catalyst may be used. 2) When an ion exchange resin is used as an organic reaction catalyst, particles are swollen due to absorption or chemical modification of the reaction solution, causing a problem of stress destruction. However, the resin of the present invention has high physical strength and low swelling stress. Even if it collides with a reaction device such as a blade or a pump impeller, it is extremely difficult to break. 3) When the resin of the present invention is used in a suspended state, when the catalyst is filtered and separated by a filter and the product is taken out, the cake resistance is small, the filter is easy to filter, and the filter is not easily clogged. Excellent maintainability.

  By reacting 1,3-butadiene with chlorine at a reaction temperature of 20 to 70 ° C. in the fine particle size anion exchange resin of the present invention, 3,4-dichloro-1-butene and 1,4-dichloro-2- By using it in the manufacturing method of dichlorobutene for producing butene, 1) With a device composed of general-purpose material metal, dichlorobutene can be obtained in high yield and less energy is required for solvent separation in the subsequent process. A reaction liquid having a high dichlorobutene concentration can be obtained, and 3,4-dichloro-1-butene, which is a raw material of the chloroprene monomer, can be obtained with higher selectivity. 2) The catalyst is a small particle size bead. Therefore, it is difficult to break and is well separated from the reaction solution. The production of 3,4-dichloro-1-butene and 1,4-dichloro-2-butene may be carried out continuously or batchwise, but it is advantageous in terms of production efficiency, production cost, etc. Preferably.

  The fine particle size anion exchange resin of the present invention is obtained by the following method.

  The seeds prepared in step a) are spherical fine particles (beads) having an average particle size of 0.3 to 2 μm obtained by emulsion polymerization of a monomer containing a crosslinking agent using a water-soluble initiator such as persulfate. ). This emulsion polymerization may be a normal emulsion polymerization using a surfactant in addition to a soap-free polymerization that does not use a surfactant, but a soap-free polymerization gives a seed that has a larger particle size and less particle size variation. Therefore, it is preferable. The monomer used is a vinyl compound capable of radical polymerization, and examples thereof include styrene, vinyl naphthalene, vinyl toluene, ethyl styrene, α-methyl styrene, chlorostyrene, chloromethyl styrene, acrylic acid ester, methacrylic acid ester, and the like. Preferred monomers are styrene, acrylic ester and methacrylic ester. The crosslinking agent is a compound having two or more double bonds capable of radical polymerization per molecule, and examples thereof include divinylbenzene, divinyltoluene, trivinylbenzene, divinylnaphthalene, diethylene glycol divinyl ether, and ethylene glycol dimethacrylate. A preferred cross-linking agent is divinylbenzene. The amount of crosslinking agent used is expressed as the degree of crosslinking (calculated by weight of crosslinking agent / (weight of monomer + crosslinking agent)). It is preferable to adjust with 1 to 5%.

  Chain transfer agents can also be used in seed preparation. Examples of the chain transfer agent include, for example, methyl 2-mercaptoacetate, ethyl 2-mercaptoacetate, propyl 2-mercaptoacetate, butyl 2-mercaptoacetate, n-octyl 2-mercaptoacetate, 2-ethylhexyl 2-mercaptoacetate, 2- Mercaptoacetate such as mercaptopropionate n-dodecyl, methyl 3-mercaptopropionate, ethyl 3-mercaptopropionate, propyl 3-mercaptopropionate, butyl 3-mercaptopropionate, n-octyl 3-mercaptopropionate 3-mercaptopropionate 2-ethylhexyl, 3-mercaptopropionate 3-mercaptopropionate such as n-dodecyl, methyl 2-mercaptopropionate, ethyl 2-mercaptopropionate, 2-mercaptopropion Mercaptopropionate such as propyl, butyl 2-mercaptopropionate, n-octyl 2-mercaptopropionate, 2-ethylhexyl 2-mercaptopropionate, n-dodecyl 2-mercaptopropionate, n-hexyl mercaptan, n- Examples thereof include alkyl mercaptans such as octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan and n-stearyl mercaptan, dialkylxanthogen disulfides such as dimethylxanthogen disulfide, diethylxanthogen disulfide, diisopropylxanthogen disulfide and diisobutylxanthogen disulfide. By using a chain transfer agent, a low molecular weight seed can be prepared, and in the next step b), when the aromatic vinyl compound monomer or the like is absorbed by the seed, a seed that easily swells can be prepared. The amount used is preferably adjusted within a range of 5 wt% or less as a concentration in the monomer in order to prevent a decrease in catalytic performance and adhesion to the reactor wall while using a low molecular weight seed.

  Next, in step b), the pH is adjusted to 6 to 9 with an appropriate buffer (for example, phosphate buffer or borate buffer), and the final slurry concentration is adjusted to 5 to 15% by weight. Then, the aromatic vinyl compound monomer, the crosslinking agent and the polymerization initiator are absorbed into the seed (seed slurry) obtained in the previous step a) to prepare a swollen seed. In the absorption to the seed, the aromatic vinyl compound monomer containing the crosslinking agent and the polymerization initiator is absorbed by the seed, and the aromatic vinyl compound monomer, the crosslinking agent and the polymerization initiator may be separately absorbed by the seed. In order to make the seed absorb, the addition of the aromatic vinyl compound monomer or the like to the seed may be a method of gradually feeding according to the speed at which the seed absorbs the aromatic vinyl compound monomer or the like. A method of adding a liquid (dispersed liquid) dispersed as fine droplets by means of ultrasonic waves or the like in water or a buffer may be used. In the latter method, an appropriate surfactant such as sodium lauryl sulfate can be used when preparing a dispersion of the aromatic vinyl compound monomer or the like.

  The aromatic vinyl compound monomer is selected from, for example, styrene, vinyl naphthalene, vinyl toluene, ethyl styrene, α-methyl styrene, chlorostyrene, chloromethyl styrene, etc., but styrene is preferred. The same crosslinking agent as that used in the above step a) can be used, and divinylbenzene is preferred, and the degree of crosslinking (calculated by the weight of the crosslinking agent / (weight of aromatic vinyl compound monomer + weight of crosslinking agent)) is the catalyst. In order to prevent degradation of performance and contamination of the apparatus, it is preferably adjusted to 2 to 7%, more preferably 3 to 5%.

  Polymerization initiators are alkyl peroxyesters such as t-butyl perbenzoate and t-butylperoxy-2-ethylhexanoate having a 10-hour half-life temperature of 40 to 100 ° C., and diacyl peroxides such as benzoyl peroxide. These organic peroxides are used alone or in combination. The amount of the polymerization initiator used is 0.05 to 2% by weight in the monomer.

  The use amount of the aromatic vinyl compound monomer and the crosslinking agent with respect to the weight of the seed in this step b) is not particularly limited, but the anion exchange resin obtained through the following steps c) to d) is a core-shell type particle. In order to prevent the structure from becoming fragile due to physical impact, the total weight of the aromatic vinyl compound monomer and the crosslinking agent is preferably 0.5 to 3 times the seed weight, more preferably 0.8 to 2 Adjust to double.

  In the next step c), the aromatic vinyl compound monomer absorbed in the swelling seed and the cross-linking agent are polymerized to prepare copolymer beads. The temperature and time depend on the polymerization initiator used, but in the range of 50 to 110 ° C., the reaction temperature should be gradually raised at a low temperature at first. If the obtained copolymer beads do not reach the desired average particle size, the steps b) and c) can be repeated until the beads have the desired average particle size.

  Step d) is a step of introducing ion exchange groups by chloromethylation and amination. Chloromethylation is a method in which a Lewis acid such as iron chloride or zinc chloride is used as a catalyst to react with chloromethyl ether at 40 to 60 ° C. for 3 to 5 hours. There is a method of generating chloromethyl ether in any one of them, and any method may be used. Excess chloromethyl ether is removed after elapse of a predetermined reaction time, followed by washing with methanol and then with water to obtain a chloromethylated resin. A secondary amine or a tertiary amine is added to the obtained wet chloromethylated resin, and a chlorine atom of the chloromethyl group is substituted to introduce an anion exchange group. In addition, when chloromethylstyrene is used as the aromatic vinyl compound monomer in the step b), the chloromethylated resin is a chloromethylated resin in a wet state because it is chloromethylated in the step c). In step d), an anion exchange group may be introduced by adding a secondary amine or a tertiary amine and replacing the chlorine atom of the chloromethyl group without chloromethylation. Here, the secondary amine or the tertiary amine includes, for example, a secondary or tertiary amine having a linear alkyl group having 2 to 5 carbon atoms, a hydroxyalkyl group or an alkenyl group, dimethylamine, trimethylamine and the like. . The larger the alkyl substituent of the amine, the more difficult it is to react, and a higher reaction temperature and longer reaction time are required, but the reaction may be carried out at 50 to 90 ° C. for 5 to 15 hours. As the catalyst for the production method of dichlorobutene, the larger the alkyl substituent of the ion exchange group nitrogen atom, the better the reaction result. Accordingly, preferred secondary amines or tertiary amines are secondary amines or tertiary amines having a linear alkyl group of 2 to 5 carbon atoms, a hydroxyalkyl group or an alkenyl group, such as diethylamine, N, N-dimethyl. Ethanolamine, triethylamine, diallylamine, triallylamine, di-n-propylamine, tri-n-propylamine, di-n-butylamine, tri-n-butylamine, di-n-pentylamine, tri-n-pentylamine and the like can be exemplified as preferred amines. Are more preferably triethylamine, tri-n-propylamine, and tri-n-butylamine, and most preferably tri-n-propylamine. After introducing the exchange group, the wet resin is obtained by washing with dilute hydrochloric acid and then with water. When used as a catalyst for the production method of dichlorobutene, moisture causes corrosion of the metal material of the reactor, so that it is 10% or less, preferably 5% or less, more preferably 2% or less by pretreatment. The removal method is not particularly limited. For example, heat evaporation or treatment with a solvent that is completely miscible with water such as acetone is used to replace the moisture inside the resin, and then the solvent is volatilized and removed under a gas stream or under reduced pressure. And so on.

  Next, a method for producing dichlorobutene using the fine particle size anion exchange resin of the present invention as a catalyst will be described.

  The solvent for carrying out the method for producing dichlorobutene of the present invention is selected from saturated hydrocarbons having 4 to 7 carbon atoms, that is, butane, pentane, hexane, heptane, etc., and even a mixture of various components such as industrial hexane. It doesn't matter.

  The reaction temperature in the method for producing dichlorobutene of the present invention is 20 to 70 ° C. When the temperature is lower than 20 ° C., it is difficult to remove the heat of reaction. Preferably it is 30-60 degreeC.

  The use amount of the fine particle size anion exchange resin in the method for producing dichlorobutene of the present invention is to suppress the non-catalytic reaction to prevent the increase of side reaction products, and to express the effects of the present invention. It is necessary that a sufficient amount of a fine particle size anion exchange resin catalyst be present in the reaction solution. Since the reaction is considered to occur on the surface of the catalyst particles, the total surface area of the catalyst particles in the reaction solution may be approximately 100 square meters or more per liter of the reaction solution. For example, if the average particle size is 1 μm, 17 g / l If the particle size is 3 μm, the catalyst concentration may be about 50 g / l or more.

  The production of 3,4-dichloro-1-butene and 1,4-dichloro-2-butene may be carried out continuously or batchwise, but it is advantageous in terms of production efficiency, production cost, etc. Preferably it is done.

  Specific embodiments of the method for producing dichlorobutene will be described by way of example with reference to FIGS. 1 and 2. However, the embodiments are merely examples, and the present invention is not limited thereto, and various conditions described below are also limited thereto. It is not something. 1 and FIG. 2 form a loop reactor in which a reaction section 1 of 1,3-butadiene and chlorine, a heat removal section 2, a circulation pump 3 and an in-line filter 4 are connected by piping, and the reaction solution is 0 in the loop. It circulates at a liquid linear velocity of 4 to 4 m / sec, and a fine particle size anion exchange resin is dispersed in the reaction solution.

  1,3-butadiene and the solvent feed 1,3-butadiene at a ratio of 100 to 400 g per liter of the solvent. These may be placed anywhere in the loop reactor, but the inhomogeneous dissolution of 1,3-butadiene may lead to an increase in undesirable side reactions in the reaction with chlorine. Feeding under high turbulent flow conditions with Reynolds number of 10,000 or more generated by an insert such as an impeller or a static mixer, and uniformly mixing and dissolving until reaching the reaction section 1.

  The circulation pump 3 may be of any type such as a centrifugal pump or a centrifugal pump, but is preferably a system that is difficult to cavitate with gas.

  The reaction unit 1 is a tube made of a general-purpose metal material such as SUS316. Here, fed chlorine is reacted and consumed at a reaction temperature of 20 to 70 ° C., preferably 30 to 60 ° C.

  Insufficient dispersion of the fed chlorine increases not only by-products but also chlorination loss of the solvent. Therefore, use of blowing means capable of highly dispersing such as a venturi nozzle, or static mixers, etc. Chlorine is fed under high turbulent flow conditions with a Reynolds number of 10,000 or more generated by means such as installing the insert in the pipe. Furthermore, the feed of chlorine is controlled by the molar ratio of 1,3-butadiene defined by the following formula 1. This represents the excess ratio of 1,3-butadiene relative to chlorine at the chlorine feed point, and is not particularly limited, but prevents an increase in by-products by preventing a high concentration of chlorine at the chlorine feed point. In order to improve the yield of dichlorobutenes, it is preferably 10 to 150, more preferably 20 to 100.

  It is desirable to feed chlorine in divided portions. At this time, the molar ratio of 1,3-butadiene at each chlorine feed point defined by Equation 1 is a value divided by the number of divisions, and since a high concentration region of local chlorine can be effectively suppressed, The benefits are great. The larger the number of divisions, the more advantageous, but the equipment becomes complicated, so 2 to 10 divisions are sufficient. As shown in the loop reactor of FIG. 1, the chlorine split feed may be split feed in the length direction of the reaction section, or in the reaction section in which a plurality of reaction tubes are arranged in parallel as shown in FIG. Divided feed may be performed for each reaction tube. In the case of FIG. 1 where the feed is divided in the length direction of the reaction section, chlorine is introduced so that the reaction solution that circulates reaches the next chlorine feed point 0.2 to 1 second after the chlorine is fed to the reaction solution that circulates. Arrange the feed section. The distance between each chlorine feed point is determined by the linear velocity of the circulating reaction liquid. When the linear velocity in the reaction part of the circulating reaction liquid is set to 1 m / sec, the chlorine feed points are arranged at intervals of 0.2 to 1 m. In the reaction section in which a plurality of reaction tubes are arranged in parallel as shown in FIG. 2, the length of each reaction tube may be set to a length required for at least 1 second for the circulating reaction liquid to pass through the reaction tube. .

  Although the concentration range of 1,3-butadiene in the reaction solution is not particularly limited, the polymerization loss of butadiene is reduced while maintaining the yield by preventing side reaction of chlorine addition to the product dichlorobutenes. In order to prevent it, it is preferably 5 to 50 g / l, more preferably 10 to 30 g / l.

  The concentration of dichlorobutene (total of 3,4-dichloro-1-butene and 1,4-dichloro-2-butene) in the reaction solution is not particularly limited, but the productivity is improved and the solvent is removed from the reaction solution. The amount is preferably 150 to 400 g / l, more preferably 200 to 300 g / l in order to prevent side reactions and improve the yield of dichlorobutene while reducing the energy required for removal.

  The reaction heat is removed in the heat removal section 2. The type is not particularly limited, but there are a method of volatilizing the solvent and removing the heat as latent heat of vaporization and recondensing and circulating the vapor, or a method using a heat exchanger, but a shell and tube (multi-tube) type heat exchanger Is preferred. As the heat removal condition, the linear velocity of the reaction solution is 1 m / second so that the fine particle size anion exchange resin dispersed in the circulating reaction solution adheres to the heat transfer surface and the decrease in heat transfer efficiency can be suppressed. The above is preferable. The heat removal unit 2 may be installed anywhere in the loop reactor, and a shell and tube (multi-tube) heat exchanger may be used as the reaction unit 1 to serve as the heat removal unit 2.

  A part of the reaction liquid is separated and extracted from the fine particle size anion exchange resin catalyst in the cross-flow type in-line filter 4, and most of the reaction liquid in which the catalyst is dispersed remains in the circulation loop of the reaction liquid. The extracted reaction solution is sent to the solvent separation step in the subsequent step. The in-line filter is preferably used by alternately installing a plurality of units in series or in parallel. The element of the in-line filter needs to have a sufficiently small pore size so that the catalyst particles in the circulating reaction solution can be completely captured. The element can be of any type such as sintered metal or sintered ceramic, as well as sintered wire mesh. The sintered wire mesh is formed by laminating fine wire meshes and bonded to each other at a high temperature, and has an advantage that the lower layer has a coarser structure and is less likely to be clogged, and can be suitably used in the method of the present invention.

  The fine particle anion exchange resin of the present invention can be used as a catalyst in a process for producing dichlorobutene, has a small particle size variation, is in the form of beads, has a high physical strength, and is extremely difficult to destroy. It is possible to provide a process excellent in operation and maintenance of the apparatus. In addition, the process for producing dichlorobutene of the present invention enables the dichlorobutene to be produced in a high concentration with a high yield and less energy required for solvent separation in the post-process, compared to the prior art, by an apparatus composed of general-purpose material metals. A reaction solution containing butene is obtained. Furthermore, it is possible to produce 3,4-dichloro-1-butene, which is a raw material for the chloroprene monomer, with higher selectivity.

It is a figure which shows the example of the loop reactor used by this invention. It is a figure which shows the other example of the loop reactor used by this invention.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to an Example.

  The composition of the reaction solution was analyzed by gas chromatography (capillary column: J & W DB-5; 0.25 mm ID × 30 m).

  The dichlorobutene yield, 3,4-dichloro-1-butene selectivity and solvent chlorination rate were calculated by the following formulas.

Dichlorobutene yield (chlorine base) = dichlorobutene produced (mol) / feed chlorine (mol)
Dichlorobutene yield (butadiene-based) = produced dichlorobutene (mol) / (feed butadiene (mol) -unreacted butadiene (mol))
3,4-dichloro-1-butene selectivity = 3,4-dichloro-1-butene / (3,4-dichloro-1-butene + 1,4-dichloro-2-butene)
Solvent chlorinated byproduct rate = Byproduct chlorinated solvent (mol) / feed chlorine (mol)
The anion exchange resin Cl content in the examples was measured by the Forhardt method as follows. 0.1 g of the dried resin was put in a conical beaker, 20 ml of pure water, 10 ml of reagent nitric acid and 10 ml of AgNO ₃ standard solution (0.05 mol / l) were added, and the mixture was stirred for 2 minutes to precipitate AgCl. Next, iron alum was added as an indicator, and excess AgNO ₃ was back titrated with a standard solution of NH ₄ SCN (0.05 mol / l) to determine the Cl content in the resin.

  The average particle size was measured using water as a dispersion medium using a particle size / particle size distribution measuring device (Microtrac HRA3920, manufactured by Nikkiso Co., Ltd.).

  In addition, the reactor used for the manufacturing method of dichlorobutene in the Example is the following loop reactors.

<Loop reactor>
Magnet type centrifugal pump as a circulation pump (manufactured by SUS316, rotational speed control by inverter), two in-line filter units connected in series (manufactured by SUS316L sintered wire mesh, 500 mesh, 3500 mesh, 200 mesh, 100 mesh, 60 mesh) , 40 mesh SUS316 wire mesh laminated and sintered, processed into a tube shape, filter section inner diameter 10 mm × length 100 mm), and reaction tube also serving as a heat removal section (SUS316, inner diameter 10 mm × length 500 mm) × 3, a chlorine feed port is installed at the inlet of each reaction tube) is connected in series to form a loop reactor having an internal volume of 0.5 liter. The solvent and 1,3-butadiene were fed in front of the suction port of the circulation pump, and chlorine gas was fed in three equal portions to the inlets of the three reaction tubes. In order to control the amount of liquid in the loop reactor at a constant level, the reaction liquid is extracted through an in-line filter by an extraction pump linked to a liquid level sensor installed immediately after the reaction tube.

Example 1
A 500 ml glass reaction vessel was charged with 300 ml of pure water, 41.0 g of styrene and 1.0 g of divinylbenzene-55, and 2.0 g of mercaptoacetic acid-2-ethylhexyl, and stirred at 250 rpm, and the inside was replaced with a nitrogen stream. As a polymerization initiator, 40 g of a 2% by weight aqueous solution of potassium persulfate was added, and the temperature was raised to 70 ° C. and reacted for 15 hours. This emulsion polymerization liquid was filtered through a 20 μm wire mesh to remove the agglomerated polymer and obtain a seed slurry having an average particle size of 1.1 μm containing 10% by weight of solids.

  100 g of the obtained seed slurry is taken in a 500 ml glass reaction vessel, and 100 ml of borate buffer and 0.4 g of 67% sodium dichromate aqueous solution as an emulsion polymerization inhibitor are added to obtain a pH 6 seed slurry. 8.2 g of monomer mixture containing (7.4 g of styrene, 0.74 g of divinylbenzene-55 (crosslinking degree 5.0%), 0.016 g of t-butyl perbenzoate, 0 of t-butyl peroxy-2-ethylhexanoate 0 .024 g) was slowly fed over 30 minutes with stirring to absorb the monomer into the seed to obtain a swollen seed (aromatic vinyl compound monomer + crosslinker weight / seed weight: 0.8 times).

  50 ml of 1% methylhydroxyethylcellulose aqueous solution was added to this swollen seed slurry, and stirring was continued at 2 hours at room temperature. The temperature was raised to 70 ° C. for 15 hours, and further reacted at 95 ° C. for 2 hours. Using the resulting slurry as a seed, 14.8 g of the monomer mixture (13.4 g of styrene, 1.33 g of divinylbenzene-55 (crosslinking degree 5.0%), 0.028 g of t-butyl perbenzoate, t- Swelled seeds were prepared and polymerized using butyl peroxy-2-ethylhexanoate (0.042 g) under the same operating conditions as the first, and the resulting slurry was treated with a 20 μm sieve, filtered under pressure, and washed with water. And dried at 60 ° C. to obtain 19 g of copolymer beads. The average particle size was 1.4 μm.

  To the obtained copolymer beads, 150 ml of chloromethyl ether and 2.2 g of iron trichloride were added and stirred and reacted at 50 ° C. for 5 hours. Excess chloromethyl ether was separated and removed with a filter, washed with methanol, and filtered with water. Thus, a chloromethylated resin was obtained. Next, 100 ml of tri-n-propylamine was added without drying, and the mixture was treated at 70 ° C. for 15 hours. The excess amine was separated by filtration, washed with dilute hydrochloric acid, filtered with water, dehydrated and filtered with acetone, It was dried in a nitrogen stream and the average particle size was 1.6 μm and the Cl content was 1.8 eq. 28 g of a fine particle size anion exchange resin of / kg was obtained.

Example 2
In a 500 ml glass reaction vessel, 100 g of the same emulsion polymerization seed slurry as in Example 1, 100 ml of borate buffer and 0.4 g of 67% sodium dichromate aqueous solution as an emulsion polymerization inhibitor are taken as a pH 6 seed slurry. Monomer mixture containing a polymerization initiator (styrene 24.8 g, divinylbenzene-55 2.5 g (crosslinking degree 5.0%), t-butyl perbenzoate 0.023 g, t-butyl peroxy-2-ethylhexanoate 0.034 g) was added, and the monomer was dispersed with an ultrasonic homogenizer and absorbed into the seed to obtain a swollen seed (aromatic vinyl compound monomer + crosslinker weight / seed weight: 2.5 times).

  Add 50 ml of 1% methylhydroxyethylcellulose aqueous solution to this swollen seed slurry, continue stirring at room temperature for 2 hours, transfer to a pressure reactor, replace with nitrogen gas, raise the temperature to 70 ° C. while stirring at 150 rpm, and react for 15 hours. The reaction was further carried out at 110 ° C. for 2 hours. The resulting slurry was lump-free with a 20 μm sieve, separated by pressure filtration, washed with water, and dried (60 ° C.) to obtain 33 g of copolymer beads having an average particle size of 1.3 μm. 20 g of this was used, chloromethylated in the same manner as in Example 1, introduced an exchange group with tri-n-propylamine, average particle size 1.8 μm, Cl content 1.5 eq. / Kg fine particle size anion exchange resin 30g was obtained.

Example 3
25 g of the fine particle size anion exchange resin obtained in Example 1 was dispersed in hexane and charged into a loop reactor, the concentration in the reaction solution was adjusted to 50 g / l, and the circulation flow rate of the solution was adjusted to 9 liters / minute. The reaction was carried out by feeding 30.0 ml of solvent hexane (industrial grade 1), 6.1 g of 1,3-butadiene per minute, and 7.0 g of chlorine gas per minute. The reaction temperature was controlled at 50 ° C. at the reaction section outlet. The 1,3-butadiene concentration in the reaction solution was 12.4 g / l, and the molar ratio of 1,3-butadiene calculated by Formula 1 was 63. The reaction solution was separated from the catalyst through an in-line filter, extracted at 33 g / min, and the residence time was 12 minutes. The 1,3-butadiene conversion was 90.6%, the dichlorobutene concentration in the reaction solution was 270 g / l, the solvent / dichlorobutene weight ratio was 1.69 (molar ratio 2.46), and the dichlorobutene yield was chlorine-based. And 96.0% based on 1,3-butadiene. In addition, 3,4-dichloro-1-butene selectivity in dichlorobutene was 71.0%, and the byproduct rate of the solvent hexane chlorinated product was 0.2%. Further, the circulation of the reaction solution was continued, and the reaction was carried out intermittently (5 hours / day) for 13 days. Table 1 shows the average particle size (MV) and reaction results during this period.

  The average particle size is 1.6 μm (coefficient of variation Cv 23%) at the start and 1.5 μm (coefficient of variation Cv 37%) after 13 days. The particle size distribution is slightly wider, and the ratio of particles less than 0.5 μm. Increased to 4.8%, but the original average particle size was maintained. The reaction results were also good. The average thinning rate of the SUS316 reaction tube in this continuous test was 0.03 mm / Y.

Example 4
25 g of the fine particle size anion exchange resin obtained in Example 2 was dispersed in hexane and charged into a loop reactor, the concentration in the reaction solution was adjusted to 50 g / l, and the circulation flow rate of the solution was adjusted to 9 liters / minute. The reaction was performed by feeding 30.0 ml of solvent hexane (industrial grade 1), 6.1 g of 1,3-butadiene per minute, and 7.4 g of chlorine gas per minute. The reaction temperature was controlled at 50 ° C. at the reaction section outlet. The 1,3-butadiene concentration in the reaction solution was 10.4 g / l, and the molar ratio of 1,3-butadiene calculated by Equation 1 was 50. The reaction solution was separated from the catalyst through an in-line filter, extracted at 33 g / min, and the residence time was 12 minutes. The 1,3-butadiene conversion was 92.2%, the dichlorobutene concentration in the reaction solution was 280 g / l, the solvent / dichlorobutene weight ratio was 1.62 (molar ratio 2.35), and the dichlorobutene yield was chlorine-based. 91.6% based on 1,3-butadiene and 95.6% based on 1,3-butadiene. The 3,4-dichloro-1-butene selectivity in dichlorobutene was 71.1%, and the byproduct rate of the solvent hexane chlorinated product was 0.2%. Further, the circulation of the reaction solution was continued, and the reaction was carried out intermittently (5 hours / day) for 15 days. Table 2 shows the average particle size (MV) and reaction results during this period.

  The average particle size is 1.8 μm at the start (variation coefficient Cv 25%), and after 15 days, 1.4 μm (variation coefficient Cv 43%), the particle size distribution becomes wider, and the proportion of particles less than 0.5 μm Although it increased to 5.1%, the change in average particle size was small. The reaction results were also good. The average thinning rate of the SUS316 reaction tube in this continuous test was 0.05 mm / Y.

Example 5
Take 380 g of emulsion polymerization seed slurry prepared under the same conditions as in Example 1 in a 1000 ml glass reaction vessel, 400 ml of borate buffer and 1.0 g of 67% aqueous sodium dichromate as an emulsion polymerization inhibitor, and seed slurry of pH 6 And a monomer mixture containing a polymerization initiator (styrene 55.0 g, divinylbenzene-55 8.0 g (crosslinking degree 7.0%), t-butyl perbenzoate 0.080 g, t-butyl peroxy-2- Ethylhexanoate (0.112 g) was added, and the monomer was dispersed with an ultrasonic homogenizer and absorbed into the seed to obtain a swollen seed (weight of aromatic vinyl compound monomer + crosslinking agent / seed weight: 1.5 times).

  This swollen seed slurry was transferred to a pressure reactor, 100 ml of 1% methylhydroxyethylcellulose aqueous solution was added and the atmosphere was replaced with nitrogen gas. After stirring at 150 rpm for 6 hours at room temperature, the temperature was raised to 70 ° C. and reacted for 15 hours. Reacted for 2 hours. The resulting slurry was freed from lumps with a 20 μm sieve, separated by pressure filtration, washed with water, and dried at 60 ° C. for 15 hours to obtain 90 g of copolymer beads. To the obtained copolymer beads, 350 ml of chloromethyl ether and 5.4 g of iron trichloride were added and stirred and reacted at 50 ° C. for 5 hours. Excess chloromethyl ether was separated and removed with a filter, washed with methanol, and then filtered with water. Thus, a chloromethylated resin was obtained. Next, half of the sample was separated without drying, 150 ml of tri-n-propylamine was added, treated at 70 ° C. for 15 hours, excess amine was filtered and separated, washed with dilute hydrochloric acid, filtered with water, filtered with acetone, After dehydration filtration in the treatment, it was dried in a nitrogen stream and the average particle size was 1.5 μm and the Cl content was 1.4 eq. Thus, 52 g of a fine particle size anion exchange resin of / kg was obtained.

Example 6
Using the fine particle size anion exchange resin obtained in Example 5, dichlorobutene was produced in the same manner as in Example 3. The results are shown in Table 3.

  The average particle size is 1.5 μm (coefficient of variation Cv 19%) at the start, and after 15 days, 1.7 μm (coefficient of variation Cv 39%), the particle size distribution becomes wide, and the ratio of particles less than 0.5 μm Although it increased to 4.1%, the change in average particle size was small. The reaction results were also good.

Example 7
50 g of a seed slurry having an average particle diameter of 1.2 μm obtained by the same operation as in Example 1 is taken in a reaction vessel, and 0.4 g of a 67% sodium dichromate aqueous solution is added as an emulsion polymerization inhibitor, and a polymerization initiator is added thereto. 7.0 g of monomer mixture (styrene 6.8 g, divinylbenzene-55 0.16 g (crosslinking degree 1.3%), t-butyl perbenzoate 0.014 g, t-butyl peroxy-2-ethylhexanoate 0 0.020 g) was dispersed in 100 ml of borate buffer with ultrasonic waves, and the seed was absorbed to obtain a swelling seed (aromatic vinyl compound monomer + crosslinker weight / seed weight: 1.4 times). .

  100 ml of 1% methylhydroxyethylcellulose aqueous solution was added to this swollen seed slurry, and stirring was continued at 1 hour at room temperature. The temperature was raised to 70 ° C. for 15 hours, and further reacted at 95 ° C. for 2 hours. Using the obtained slurry as a seed, monomer mixture 10.7 g (styrene 10.1 g, divinylbenzene-55 0.5 g (crosslinking degree 2.6%), t-butyl perbenzoate 0.020 g, t-butyl peroxy- 2-ethylhexanoate (0.031 g) was added to boric acid buffer (100 ml) by ultrasonic dispersion, and the seed was absorbed into the monomer to obtain a swollen seed (aromatic vinyl compound monomer + crosslinker weight / seed (Weight: 0.9 times).

  Furthermore, swelling seed preparation and polymerization were performed twice under the same mixture of monomers (crosslink degree: 2.6%) and the same conditions (vinyl compound monomer + crosslinker weight / seed weight: 0.9 times). The resulting slurry was treated with a 20 μm sieve, pressure filtered, washed with water, and dried at 60 ° C. to obtain copolymer beads. The average particle size was 3.1 μm.

  The obtained copolymer beads were chloromethylated in the same manner as in Example 1, and ion exchange groups were introduced with triethylamine, the average particle size was 3.9 μm, the Cl content was 2.1 eq. / Kg fine particle size anion exchange resin was obtained.

  This resin was dispersed in hexane and charged into a loop reactor. The concentration in the liquid was 50 g / l, and the flow rate was adjusted to 9 liters / minute and circulated. Table 4 shows the change in circulation days and average particle size. After 13 days, the average particle size became 3.7 μm, and the average particle size hardly changed.

Comparative Example 1
Monomer mixture containing a polymerization initiator (styrene 60.0 g, divinylbenzene-55 6.0 g (crosslinking degree 5.0%), t-butyl perbenzoate 0.07 g, t-butyl peroxy-2-ethylhexanoate 0.130 g) was charged into a 1 L autoclave together with 750 g of a 4 wt% aqueous polyvinyl alcohol solution and 1.0 g of sodium dichromate and stirred at 3000 rpm, and reacted at room temperature for 0.5 hours at 70 ° C. for 15 hours and further at 110 ° C. for 2 hours. The slurry was taken out, the lump was removed with a 100 μm sieve, and a suspension polymerization seed was obtained by filtration, washing with water and drying. The average particle size was 12 μm. 50 g of the obtained seed was dispersed in 130 g of pure water, and 3.3 g of 1% sodium lauryl sulfate aqueous solution and 0.4 g of 67% sodium dichromate aqueous solution were added and stirred. To this slurry, a monomer mixture (styrene 45.5 g, divinylbenzene-4.5 4.5 g (crosslinking degree 5%), t-butyl perbenzoate 0.09 g, t-butyl peroxy-2-ethylhexanoate 0.06 g) Was gradually added over 15 minutes to be absorbed into the seed to obtain a swollen seed (aromatic vinyl compound monomer + crosslinker weight / seed weight: 1.0 times).

  Next, gelatin solution (42 g of warm water, 3.3 g of 1% sodium lauryl sulfate aqueous solution, 0.5 g of gelatin) was added, and polymerization was carried out at 70 ° C. for 10 hours and at 110 ° C. for 3 hours. The obtained copolymer was used as a seed, and the same monomer mixture as described above was absorbed to form a swelling seed (aromatic vinyl compound monomer + crosslinker weight / seed weight: 0.5 times). Polymerization was performed under the same conditions to obtain 150 g of gel copolymer beads having an IPN structure. Next, ion exchange groups were introduced in the same manner as in Example 1, and the average particle size was 15 μm, the Cl content was 1.1 eq. / Kg of anion exchange resin was obtained.

  This resin was dispersed in hexane and charged into a loop reactor. The concentration in the liquid was 50 g / l, and the flow rate was adjusted to 9 liters / minute and circulated. Table 5 shows the change in circulation days and average particle size. Particle breakage progressed significantly.

Comparative Example 2
Magnet type centrifugal pump (wet contact part Teflon (registered trademark)) as a circulation pump and reaction tube that also serves as a heat removal part (made of SUS316, inner diameter 10 mm × length 500 mm × 3, chlorine feed port at each reaction tube inlet And a mechanism for extracting a part of the reaction solution out of the system by an open / close valve interlocked with the pressure sensor is connected in series to form a loop reactor. The reaction was carried out under the same flow rate conditions as in the Examples except that pyridine was dissolved in hexane at a concentration of 0.2 g / l as a catalyst and used by continuously feeding.

  The dichlorobutene yield was 93.0% on a chlorine basis, 94.5% on a 1,3-butadiene basis, and the selectivity for 3,4-dichloro-1-butene was 51.2%. The average thinning rate of the manufactured reaction tube was 3.2 mm / Y, and severe corrosion was observed.

Comparative Example 3
The same loop reactor as in the example was used, and the reaction was performed without catalyst. The circulation rate of the liquid was adjusted to 6 liters / minute, the solvent hexane (first grade for industrial use) was fed at 30.0 ml / min, 1,3-butadiene at 4.8 g / min, and chlorine gas at 5.3 g / min. Reacted. The reaction temperature was controlled at 50 ° C. at the reaction section outlet. The reaction solution was extracted at 30 g / min through an in-line filter. The 1,3-butadiene conversion rate was 77.8%, the dichlorobutene concentration in the reaction solution was 170 g / l, and the solvent / dichlorobutene weight ratio was 4.7 (molar ratio 6.8). The yield of dichlorobutene was 77.7% on the basis of chlorine, 83.2% on the basis of 1,3-butadiene, and the by-product rate of the solvent hexane chlorinated product was 2.2%. It was. The 3,4-dichloro-1-butene selectivity in dichlorobutene was 45.1%, which was lower than that when an ion exchange resin was used as a catalyst.

Comparative Example 4
Small anion exchange resin Dowex 1 × 8 with an average particle size of 77 μm as anion exchange resin (matrix resin styrene, gel type, quaternary ammonium type strong base in which ion exchange group nitrogen atom is substituted with methyl group) The functional resin (Cl type) was dehydrated and filtered by acetone treatment and then dried with a nitrogen stream. 50 g of the obtained dried beads were dispersed in hexane and charged in the same loop reactor as in the example. The concentration in the reaction solution was adjusted to 100 g / l, and the circulation rate of the solution was adjusted to 6 liters / minute. The reaction was carried out by feeding 30.0 ml of solvent hexane (industrial grade 1), 5.9 g of 1,3-butadiene per minute, and 6.1 g of chlorine gas per minute. The reaction temperature was controlled at 50 ° C. at the reaction section outlet. The reaction solution was separated from the catalyst through an in-line filter and extracted at 32 g / min. The 1,3-butadiene conversion was 98.2%, the dichlorobutene concentration in the reaction solution was 210 g / l, and the solvent / dichlorobutene weight ratio was 2.18 (molar ratio 3.17). The yield of dichlorobutene is 88.1% on a chlorine basis, 72.0% on a 1,3-butadiene basis, the byproduct rate of the solvent hexane chlorinated product is 0.76%, and 3,4-dichloro- in dichlorobutene The 1-butene selectivity was 52.3%.

1 Reaction unit 2 Heat removal unit 3 Circulation pump 4 In-line filter

Claims (8)

Used in a method for producing dichlorobutene in which 1,3-butadiene is reacted with chlorine in a solvent at a reaction temperature of 20 to 70 ° C. to produce 3,4-dichloro-1-butene and 1,4-dichloro-2-butene to a fine径陰ion exchange resin as a catalyst, the average particle diameter of Ri 0.5~10μm der, secondary amine having a straight-chain alkyl group, a hydroxyalkyl group or an alkenyl group having carbon atoms 2 to 5 Alternatively , a fine particle size anion exchange resin having an anion exchange group introduced by a tertiary amine . Fine particle size anion exchange resin
a) Emulsion polymerization of a monomer containing a crosslinking agent to prepare spherical fine particles as seeds;
b) A swelling seed is prepared by absorbing an aromatic vinyl compound monomer, a crosslinking agent and a polymerization initiator in this seed,
c) Polymerizing the aromatic vinyl compound monomer and the crosslinking agent absorbed in the swelling seed to prepare copolymer beads,
d) The resulting copolymer beads are chloromethylated as necessary, and then an anion exchange group is introduced by a secondary or tertiary amine having a linear alkyl group, a hydroxyalkyl group or an alkenyl group having 2 to 5 carbon atoms. The fine particle size anion exchange resin according to claim 1, which is obtained by: a) Emulsion polymerization of a monomer containing a crosslinking agent to prepare spherical fine particles as seeds;
b) A swelling seed is prepared by absorbing an aromatic vinyl compound monomer, a crosslinking agent and a polymerization initiator in this seed,
c) Polymerizing the aromatic vinyl compound monomer and the crosslinking agent absorbed in the swelling seed to prepare copolymer beads,
d) The resulting copolymer beads are chloromethylated as necessary, and then an anion exchange group is introduced by a secondary or tertiary amine having a linear alkyl group, a hydroxyalkyl group or an alkenyl group having 2 to 5 carbon atoms. The method for producing a fine particle size anion exchange resin according to any one of claims 1 and 2 . In the presence of the fine particle size anion exchange resin according to claim 1 or 2, 1,3-butadiene is reacted with chlorine in a solvent at a reaction temperature of 20 to 70 ° C., and 3,4-dichloro-1- A process for producing dichlorobutene, which comprises producing butene and 1,4-dichloro-2-butene. A loop reactor in which a reaction section, a heat removal section, a circulation pump and an in-line filter are connected by piping to form a loop reactor in which a reaction liquid in which a fine particle size anion exchange resin is dispersed is circulated by a circulation pump. Using,
1) Feed 1,3-butadiene and solvent to the reaction solution to be circulated and mix well,
2) Under high turbulent flow conditions with a Reynolds number of 10,000 or more, chlorine is fed and mixed and dispersed in the reaction solution to react 1,3-butadiene and chlorine, and 3,4-dichloro-1-butene and 1,4- Producing dichloro-2-butene,
3) The produced 3,4-dichloro-1-butene and 1,4-dichloro-2-butene were extracted out of the loop reactor together with a part of the reaction solution in the in-line filter, and the fine particle size anion exchange resin was extracted from the loop reactor. Circulate in the feed region of 1,3-butadiene and solvent together with most of the reaction liquid,
4) Heat removal is performed at any place in the loop by the heat removal unit.
The method for producing dichlorobutene according to claim 4 . The method for producing dichlorobutene according to claim 4 or 5 , wherein the solvent is a saturated hydrocarbon having 4 to 7 carbon atoms. The method for producing dichlorobutene according to claim 5 or 6, wherein the in-line filter is made of sintered wire mesh. The molar ratio of 1,3-butadiene defined by the following formula 1 is 10 to 150, the 1,3-butadiene concentration in the reaction solution is 5 to 50 g / l, and the dichlorobutene concentration in the reaction solution is 150 to 400 g / l. The method for producing dichlorobutene according to any one of claims 4 to 7 , wherein the reaction is performed under the condition of l.

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