JP2005002083A - Method for producing chlorobenzene - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for efficiently utilizing a polychlorinated aromatic compound by-produced in the production of p-dichlorobenzene by the chlorination reaction of benzene and having low utility value, concretely, to provide a technique for producing useful chlorobenzene from the polychlorinated aromatic compound and benzene. <P>SOLUTION: Chlorobenzene is produced by the reaction of a polychlorinated aromatic compound with benzene by using a zeolite having fine pores composed of ≥10-membered oxygen ring. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing chlorobenzene from a reaction between a polychlorinated aromatic compound and benzene. Specifically, the present invention relates to a method for producing chlorobenzene by reacting a polychlorinated aromatic compound having low utility value with benzene to convert it into chlorobenzene in the presence of a zeolite having pores having 10 or more oxygen rings as a catalyst.
[0002]
[Prior art]
Paradichlorobenzene is a highly useful polychlorinated aromatic compound as a raw material for PPS (polyphenylene sulfide) resin and the like. In recent years, with the expansion of PPS resin, an increase in the amount of paradichlorobenzene produced is desired. However, in the production of paradichlorobenzene by chlorination of benzene and / or chlorobenzene, a large amount of orthodichlorobenzene and trichlorobenzene are by-produced, and the treatment of these polychlorinated aromatic compounds with low utility value has become a major problem. It was.
[0003]
In addition, polychlorinated aromatic compounds such as polychlorinated biphenyl (PCB) have a problem of being extremely toxic and cannot be used chemically and forced to be stored.
[0004]
Such a technique for converting a polychlorinated aromatic compound having a low utility value from a reaction with benzene to chlorobenzene (hereinafter referred to as transchlorination) is well known (for example, Patent Documents 1 to 5, Non-Patent Documents). Reference 1 and 2). Here, chlorobenzene itself is a compound having high utility value as an intermediate raw material in the production of paradichlorobenzene as well as a raw material for pharmaceuticals and agricultural chemicals.
[0005]
[Patent Document 1]
JP-A-1-311032 (first page)
[Patent Document 2]
Japanese Patent Laid-Open No. 4-312539 (first page)
[Patent Document 3]
Japanese Patent Laid-Open No. 6-065119 (first page)
[Patent Document 4]
JP-A-10-218806 (first page)
[Patent Document 5]
JP 10-218807 A (first page)
[Non-Patent Document 1]
Chemistry Letters, 1987, page 2051
[Non-Patent Document 2]
The Chemical Society of Japan, 1989, No. 12, 1999 pages [0006]
[Problems to be solved by the invention]
The methods described in Patent Document 1 and Non-Patent Documents 1 and 2 have proposed a catalyst in which palladium chloride is supported on activated carbon in the transchlorination reaction. However, since palladium chloride has a low melting point, it tends to volatilize and has a problem in terms of catalyst stability. Further, since palladium is an expensive noble metal, it has a problem in terms of economy.
[0007]
The method described in Patent Document 2 has proposed a catalyst containing Ru as an element or in the form of a compound in the transchlorination reaction. However, this catalyst system has insufficient catalytic activity and has a problem of using expensive noble metals.
[0008]
The method described in Patent Document 3 is characterized in that a hydrogen halide such as hydrogen chloride is present in the presence of a catalyst in the transchlorination reaction, and the extension of the catalyst life is disclosed. Although this method certainly suggests extending the life of the catalyst, the presence of hydrogen halide leads to corrosion of the materials used in the reaction system (for example, carbon steel and stainless steel). There were problems such as applying.
[0009]
Patent Documents 4 and 5 propose a method for producing paradichlorobenzene including a transchlorination step. In the transchlorination step, a solid acid catalyst such as silica / alumina, crystalline aluminosilicate, activated alumina or activated carbon is used. A supported palladium chloride catalyst and the like are disclosed. However, the solid acid catalyst does not necessarily have sufficient catalytic activity, and the palladium chloride catalyst supported on the activated carbon has catalyst stability and economical problems as described above.
[0010]
This invention is made | formed in view of said subject, The objective is to provide the technique which manufactures a useful chlorobenzene from a polychlorinated aromatic compound and benzene as a raw material.
[0011]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventors have newly used a zeolite having specific pores as a catalyst in a method for producing chlorobenzene from a reaction between a polychlorinated aromatic compound and benzene. A novel method for producing chlorobenzene has been found and the present invention has been completed.
[0012]
That is, the present invention is a process for producing chlorobenzene from a reaction between a polychlorinated aromatic compound and benzene, wherein a zeolite having pores having 10 or more oxygen rings is used as a catalyst. .
[0013]
The polychlorinated aromatic compound of the present invention is a compound containing an aromatic moiety and chlorine. As the polychlorinated aromatic compound, a compound having at least 4 carbon atoms and at least 2 chlorine atoms is preferable. Any compound in this category is not particularly limited, but 2,3-dichlorofuran, 2,4-dichlorofuran, 2,5-dichlorofuran, isomers of trichlorofuran, tetrachlorofuran, 2 , 3-dichloropyrrole, 2,4-dichloropyrrole, 2,5-dichloropyrrole, 2,3-dichlorothiophene, 2,4-dichlorothiophene, 2,5-dichlorothiophene, 2,3-dichloropyridine, 2, 4-dichloropyridine, 2,5-dichloropyridine, 2,6-dichloropyridine, trichloropyridine isomer, tetrachloropyridine isomer, pentachloropyridine, orthodichlorobenzene, metadichlorobenzene, paradichlorobenzene, 1,2, 3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5 Trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, 2,3-dichlorotoluene, 2,4-dichlorotoluene, 2,5-dichloro Toluene, 2,6-dichlorotoluene, 2,3-dichloroanisole, 2,4-dichloroanisole, 2,5-dichloroanisole, 2,6-dichloroanisole, 2-chlorobenzyl chloride, 3-chlorobenzyl chloride, 4 -Chlorobenzyl chloride, 5-chlorobenzyl chloride, 6-chlorobenzyl chloride, 2,2'-dichlorobiphenyl, 2,3'-dichlorobiphenyl, 2,4'-dichlorobiphenyl, 2,5'-dichlorobiphenyl, 2 , 6'-dichlorobiphenyl, 2,6-dichlorobiphenyl 2,5-dichlorobiphenyl, 2,4-dichlorobiphenyl, 2,3-dichlorobiphenyl, trichlorobiphenyl isomer, tetrachlorobiphenyl isomer, pentachlorobiphenyl isomer, hexachlorobiphenyl isomer, heptachrome Biphenyl isomer, octachlorobiphenyl isomer, nonachlorobiphenyl isomer, decachlorobiphenyl, 1,2-dichloronaphthalene, 1,3-dichloronaphthalene, 1,4-dichloronaphthalene, 1,5-dichloronaphthalene 1,6-dichloronaphthalene, 1,7-dichloronaphthalene, 1,8-dichloronaphthalene, trichloronaphthalene isomer, tetrachloronaphthalene isomer, pentachloronaphthalene isomer, hexachloronaphthalene isomer, heptachloro Naphtha Isomer, octachloronaphthalene, dichloroanthracene isomer, tetrachloroanthracene isomer, pentachloroanthracene isomer, hexachloroanthracene isomer, heptachloroanthracene isomer, octachloroanthracene isomer, nona Chloroanthracene, decachloroanthracene, 1,2-dichloroquinoline, 1,3-dichloroquinoline, 1,4-dichloroquinoline, 1,5-dichloroquinoline, 1,6-dichloroquinoline, 1,7-dichloroquinoline, trichloro Quinoline isomer, tetrachloroquinoline isomer, pentachloroquinoline isomer, hexachloroquinoline isomer, heptachloroquinoline, 1,1-dichloroindene, 1,2-dichloroindene, 1,3-dichloroindene, 1, 4 Dichloroindene, 1,5-dichloroindene, 1,6-dichloroindene, 1,7-dichloroindene, 1,2-dichlorofluorene, 1,3-dichlorofluorene, 1,4-dichlorofluorene, 1,5-dichloro Fluorene, 1,6-dichlorofluorene, 1,7-dichlorofluorene, 1,8-dichlorofluorene, 9,9-dichlorofluorene, trichlorofluorene isomer, tetrachlorofluorene isomer, pentachlorofluorene isomer, Hexachlorofluorene isomer, heptachlorofluorene isomer, octachlorofluorene isomer, nonachlorofluorene isomer, decachlorofluorene, 1,2-dichloropyrene, 1,3-dichloropyrene, 1,4-dichloro Pyrene, 1,5-dichloropyrene, 1,6- Dichloropyrene, 1,7-dichloropyrene, 1,8-dichloropyrene, 1,9-dichloropyrene, 1,10-dichloropyrene, trichloropyrene isomer, tetrachloropyrene isomer, pentachloropyrene isomer And chloroaromatic polymers such as hexachloropyrene isomer, heptachloropyrene isomer, octachloropyrene isomer, nonachloropyrene isomer, decachloropyrene, and polychlorobiphenyl (PCB). However, in the present invention, these can be used alone or in combination.
[0014]
Of these, metadichlorobenzene, orthodichlorobenzene, paradichlorobenzene or a mixture thereof is preferably used because of the high yield of chlorobenzene.
[0015]
The zeolite used in the present invention is characterized by having pores having an oxygen 10-membered ring or more. That is, since the zeolite of the present invention has pores having a 10-membered oxygen ring or more, chlorobenzene can be obtained in a high yield.
[0016]
Here, zeolite is a general term for crystalline porous aluminosilicate. The basic unit of the structure has a tetrahedral structure _(SiO ⁴⁾ is ⁴ and _(AlO ⁴⁾ (a TO ₄ together) ⁵ units, 4 single TO ₄ units next four vertices oxygen respectively By sharing with one TO ₄ unit, it is three-dimensionally connected one after another to form a crystal. Note that metallosilicates in which aluminum of crystalline porous aluminosilicate is replaced with other metals are also included in the zeolite.
[0017]
The oxygen 10-membered ring is simply called a 10-membered ring, and the number means the total number of oxygen contained in the skeleton forming the pore site, that is, the pores of the zeolite having the pore diameter of the oxygen 10-membered ring. The number of oxygen contained in the skeleton is 10. In the case of a zeolite having a plurality of pores, the largest pore diameter is indicated (Yoshio Ono and Takeaki Yashima, Science and Engineering of Zeolite, Kodansha Scientific, 2000). Since the pore diameter of the zeolite used in the present invention is composed of an oxygen 10-membered ring or more, the pore diameter is 5 angstroms or more.
[0018]
Although not particularly limited zeolites having 10-membered oxygen ring or more pores, for example, AlPO ₄ -11 as zeolites having fine pores of oxygen ten-membered rings (AEL), EU-1 ( EUO), ferrierite Wright (FER), Hulandite (HEU), ZSM-5 (MFI), NU-87 (NES), Theta-1 (TON), Weinebeite (WEI) and the like, and have oxygen 12-membered ring pores AlPO ₄ -5 as zeolite _{(AFI), AlPO 4 -31 (} ATO), beta (BEA), CIT-1 ( CON), X (FAU), Y (FAU), USY (FAU), faujasite (FAU) , L (LTL), mordenite (MOR), gmelinite (GME), ZSM-12 (MTW), offretite (OFF), etc. Zeolites having pore of 14-membered ring, clover light _{(-CLO), VPI-5 (} VFI), AlPO 4 -8 (AET), CIT-5 (CFI), UTD-1 (DON) or the like is exemplified Is done. Here, the symbol in parentheses attached to the zeolite name exemplified above means a structure code (source: WH Meier, DH Olson, Ch. Baelocher ed., Atlas of Zeolite Structure Types, 4th. Ed., Elsevier, 1996).
[0019]
These zeolites can be used alone or in combination of two or more. Among these, since conversion to chlorobenzene can be efficiently performed, zeolite having oxygen 12-membered ring pores is preferably used, more preferably zeolite having FAU or BEA structural code is used, and still more preferably. Y-type zeolite or USY-type zeolite is used.
[0020]
The zeolite having pores of 10 or more oxygen rings used in the present invention can be used in a powder form. Moreover, it can be used as molded products such as pellets and tablets by compression molding. When used as a molded product, alumina sol, silica sol or the like can be added as a binder to form a molded product.
[0021]
In the present invention, the ratio of the polychlorinated aromatic compound to be reacted with benzene is not particularly limited, but it is preferably carried out at a molar ratio of 0.01: 1 to 100: 1.
[0022]
In the present invention, the reaction format for producing chlorobenzene from the reaction of the polychlorinated aromatic compound and benzene is not particularly limited, and can be performed in any reaction format, for example, fixed bed gas phase flow type, fixed bed It can be carried out in a liquid phase flow system or a suspension bed batch system. Of these, chlorobenzene is preferably obtained in a fixed bed gas-phase flow type because chlorobenzene is obtained in a high yield. The reaction temperature is not particularly limited, but is preferably 200 ° C. to 600 ° C., more preferably 250 ° C. to 550 ° C. because it can be efficiently converted into chlorobenzene. The reaction pressure is not particularly limited, but is usually 0.01 to 50 MPa in absolute pressure, preferably 0.1 to 30 MPa. The gas hourly space velocity of the reaction (GHSV) is, because it can efficiently convert the chlorobenzene, preferably ^{0.2hr -1 ~1,000hr} -1, more preferably a ^{1hr -1 ~800hr} -1. Here, the gas hourly space velocity (GHSV) represents the total volume of the supply amount of the polychlorinated aromatic compound and benzene per unit time (hr) per unit catalyst volume.
[0023]
In the present invention, in order to suppress side reactions, the above reaction is preferably carried out in an atmosphere in which oxygen is not substantially present and / or in an inert gas atmosphere. Specifically, it is exemplified that the reaction is carried out only with the polychlorinated aromatic compound, benzene and zeolite during the reaction. Alternatively, the reaction with the above polychlorinated aromatic compound, benzene and zeolite is exemplified by carrying out the reaction in the presence of an inert gas. Although it does not restrict | limit especially as an inert gas, For example, nitrogen, helium, or argon is mentioned, These inert gases can be used individually, and can also be used in mixture of 2 or more types It is. In addition, the partial pressure of the inert gas used at the time of reaction is 0.001-30 MPa, Preferably, it is 0.01-20 MPa, More preferably, it is 0.1-10 MPa. In the present invention, although not particularly limited, the oxygen contained in the above-mentioned polychlorinated aromatic compound, benzene, and zeolite having pores of 10-membered oxygen or more to be provided during the reaction is reduced to 50 ppm or less. It is preferable. Although not particularly limited, the polychlorinated aromatic compound, benzene, and zeolite before the reaction are stored under the inert gas atmosphere and handled under the inert gas atmosphere even during the reaction. Is preferred.
[0024]
In the present invention, the process for producing chlorobenzene from the reaction between the polychlorinated aromatic compound and benzene is not particularly limited, and can be performed in any form. For example, in the manufacturing method of paradichlorobenzene by chlorination of benzene or / and chlorobenzene, chlorobenzene can be manufactured by passing through the following processes 1-4.
That is, (Step 1) A step of producing dichlorobenzene such as paradichlorobenzene, metadichlorobenzene and orthodichlorobenzene by chlorination of benzene and / or chlorobenzene. (Step 2) A step of isolating paradichlorobenzene from the product obtained in Step 1. (Step 3) A step of producing chlorobenzene by the method for producing chlorobenzene using the residue separated in step 2 as a polychlorinated aromatic compound. (Step 4) A step of isolating chlorobenzene from the product obtained in Step 3 and circulating the residue as a polychlorinated aromatic compound in Step 3 is included. Although it does not specifically limit as a manufacturing method of the dichlorobenzene of the process 1, For example, the method of chlorinating with chlorine from benzene and / or chlorobenzene is mentioned. In this case, it is preferable to use a Lewis acid such as iron chloride or aluminum chloride as a catalyst because the selectivity of paradichlorobenzene can be increased. The dichlorobenzene obtained in step 1 is usually composed of isomers of paradichlorobenzene, metadichlorobenzene and orthodichlorobenzene, and in step 2, paradichlorobenzene is isolated. Although it does not specifically limit as a isolation method of the para dichlorobenzene of the process 2, Methods, such as crystallization, are mentioned. In the method for producing chlorobenzene in Step 3, residues such as metadichlorobenzene, orthodichlorobenzene separated in Step 2 and paradichlorobenzene not crystallized are used as polychlorinated aromatic compounds. The isolation of chlorobenzene in step 4 is not particularly limited, but is performed by a method such as distillation, and the residue is recycled to step 3 and used as a polychlorinated aromatic compound.
[0025]
Here, the produced chlorobenzene may be used as a raw material for pharmaceuticals and agricultural chemicals, or may be recycled to the step 1 and used as a raw material for paradichlorobenzene.
[0026]
【Example】
Although the content of the present invention is not limited by the examples, the present invention will be described in more detail by examples.
[0027]
The product obtained by this reaction was a gas chromatography analyzer (manufactured by Shimadzu Corporation, product name: GC-14A) for both the reaction liquid (liquid phase) and the outlet gas (gas phase). -Analyzed using ethylbenzene. A GC-14A capillary column (manufactured by Varian, product name: CP-WAX) was attached, nitrogen was used as a carrier gas, the column temperature was maintained at an initial temperature of 80 ° C. for 8 minutes, and then 170 ° C. at 9 ° C. per minute. The temperature was raised and analyzed.
[0028]
(Example 1) 30% by weight of alumina sol (containing 10% alumina) as alumina is added to Y-type zeolite (product name: HSZ-341NHA manufactured by Tosoh Corporation) exchanged with NH ₄ ions, and the diameter is 3 mm. It was granulated into a cylindrical pellet having a height of 3 mm. Then, after drying overnight at 100 ° C., air calcination was performed at 500 ° C. for 5 hours to obtain a zeolite catalyst exchanged with H ions. 10 ml of this zeolite catalyst was filled in a reaction tube, nitrogen was circulated at 10 ml per minute under normal pressure, heated in an electric furnace, and heated to 400 ° C. Next, a raw material solution in which benzene and orthodichlorobenzene were mixed at a molar ratio of 3: 1 was supplied at a rate of 0.083 ml per minute by a pump. Three hours after the start of the reaction, a gas-liquid separator was placed at the outlet of the reaction tube to collect the reaction liquid and the outlet gas. The GHSV was 430 hr ⁻¹ . The conversion rate, selectivity and yield of the reaction product were calculated from the following equations based on the results of gas chromatography.
(1) Conversion (%) = (moles of orthodichlorobenzene reacted per unit time / moles of orthodichlorobenzene fed per unit time) × 100
(2) Selectivity (%) = (number of moles of chlorobenzene produced per unit time / 2 / number of moles of orthodichlorobenzene reacted per unit time) × 100
(3) Yield (%) = conversion rate × selectivity / 100
As a result, the conversion was 14.9%, the selectivity for chlorobenzene was 79.9%, and the yield of chlorobenzene was 11.9%.
[0029]
(Example 2) The same as Example 1 except that USY type zeolite (manufactured by Tosoh Corporation, product name: HSZ-350HUA) was used instead of Y type zeolite (manufactured by Tosoh Corporation, product name: HSZ-341NHA). A zeolite catalyst was prepared by the method and the reaction was carried out. As a result, the conversion was 9.4%, the selectivity for chlorobenzene was 79.0%, and the yield of chlorobenzene was 7.4%.
[0030]
(Example 3) The same as Example 1 except that β-type zeolite (product name: HSZ-940NHA) was used instead of Y-type zeolite (product name: HSZ-341NHA). A zeolite catalyst was prepared by the method and the reaction was carried out. As a result, the conversion was 6.5%, the selectivity for chlorobenzene was 24.0%, and the yield of chlorobenzene was 1.6%.
[0031]
(Example 4) A zeolite catalyst was prepared in the same manner as in Example 1 except that the reaction temperature was set to 430 ° C, and the reaction liquid and outlet gas were collected after 1 hour from the start of the reaction. Went. As a result, the conversion was 61.6%, the selectivity for chlorobenzene was 63.8%, and the yield of chlorobenzene was 39.3%.
[0032]
(Example 5) A zeolite catalyst was prepared in the same manner as in Example 1 except that the reaction temperature was set to 450 ° C, and the reaction liquid and outlet gas were collected after 1 hour from the start of the reaction. Went. As a result, the conversion was 72.5%, the selectivity for chlorobenzene was 69.1%, and the yield of chlorobenzene was 50.1%.
[0033]
(Example 6) In the same manner as in Example 1, except that the molar ratio of benzene and orthodichlorobenzene was set to a ratio of 5: 1, and the reaction was started and the reaction liquid and outlet gas were collected after 1 hour. A zeolite catalyst was prepared and reacted. As a result, the conversion was 45.8%, the selectivity for chlorobenzene was 70.3%, and the yield of chlorobenzene was 32.2%.
[0034]
(Example 7) In the same manner as in Example 1, except that the molar ratio of benzene to orthodichlorobenzene was set to a ratio of 1: 1 and the reaction was started and the reaction liquid and the outlet gas were collected after 1 hour. A zeolite catalyst was prepared and reacted. As a result, the conversion was 25.8%, the selectivity for chlorobenzene was 36.8%, and the yield of chlorobenzene was 9.5%.
[0035]
(Comparative Example 1) pelletized γ-Al 2 _O 3 _{(manufactured} by Mizusawa Industrial Chemicals, Ltd., product name: DS-5) except for the use of it as a catalyst, the reaction was performed in the same manner as in Example 1. As a result, the conversion rate was 0.2%, the chlorobenzene selectivity was 50%, and the chlorobenzene yield was 0.1%.
[0036]
(Comparative Example 2) pelletized _gamma-Al 2 _{O 3} (manufactured by Sumitomo Chemical Co., product name: KHA-24) except that was used as such as a catalyst, the reaction was performed in the same manner as in Example 1. As a result, the conversion rate was 0% and the chlorobenzene yield was 0%.
[0037]
(Comparative Example 3) A pellet-shaped A-type zeolite (manufactured by Tosoh, product name: Zeolum A-4) was immersed in an aqueous 1N ammonium chloride solution having a weight ratio of 10 times at 60 ° C. for 5 hours. After filtration, the same operation was repeated twice again, followed by filtration and washing with water to obtain A-type zeolite exchanged with NH ₄ ions. The zeolite was dried at 100 ° C. overnight and then air calcined at 500 ° C. for 5 hours to obtain A-type zeolite exchanged with H ions.
[0038]
The reaction was carried out in the same manner as in Example 1 except that the A-type zeolite thus prepared was used. As a result, the conversion rate was 0.4%, the selectivity of chlorobenzene was 68.8%, and the chlorobenzene yield was 0.3%.
[0039]
【The invention's effect】
The present invention provides an efficient utilization technique of a polychlorinated aromatic compound having low utility value, and specifically provides a technique for producing useful chlorobenzene from a polychlorinated aromatic compound and benzene as raw materials. That is.

Claims (12)

A method for producing chlorobenzene from a reaction of a polychlorinated aromatic compound and benzene, wherein a zeolite having pores having 10 or more oxygen rings is used as a catalyst. The method for producing chlorobenzene according to claim 1, wherein the number of carbon atoms contained in the polychlorinated aromatic compound is at least 4 and at least the number of chlorine atoms is 2 or more. The method for producing chlorobenzene according to claim 1 or 2, wherein the polychlorinated aromatic compound is metadichlorobenzene, orthodichlorobenzene, paradichlorobenzene or a mixture thereof. The method for producing chlorobenzene according to any one of claims 1 to 3, wherein the zeolite having pores of 10 or more oxygen rings is zeolite having pores of 12-membered oxygen rings. The method for producing chlorobenzene according to claim 4, wherein the zeolite having pores having a 12-membered oxygen ring is a zeolite having a structure code of FAU or BEA. The method for producing chlorobenzene according to any one of claims 1 to 5, wherein the reaction format is a fixed bed gas phase circulation format. The method for producing chlorobenzene according to any one of claims 1 to 6, wherein the reaction temperature is 200 ° C to 600 ° C. 8. The method for producing chlorobenzene according to claim ¹ , wherein a gas hourly space velocity (GHSV) is 0.2 hr ^{−1 to} 1,000 hr ⁻¹ . The manufacturing method of the chlorobenzene characterized by passing through the following processes 1-4 at least.
Step 1: A step of producing dichlorobenzene by chlorination of benzene and / or chlorobenzene.
Step 2: Isolating paradichlorobenzene from the product obtained in Step 1.
Step 3; A step of producing chlorobenzene by the method according to any one of claims 1 to 8, wherein the residue separated in Step 2 is used as a polychlorinated aromatic compound.
Step 4: A step of isolating chlorobenzene from the product obtained in Step 3 and circulating the residue as the polychlorinated aromatic compound in Step 3. The method for producing chlorobenzene according to claim 9, wherein the dichlorobenzene obtained in step 1 comprises isomers of paradichlorobenzene, metadichlorobenzene and orthodichlorobenzene. The method for producing chlorobenzene according to claim 9 or 10, wherein the method for isolating paradichlorobenzene in Step 2 is crystallization. 12. The method for producing chlorobenzene according to claim 11, wherein the residue separated in step 2 is metadichlorobenzene, orthodichlorobenzene, and paradichlorobenzene that has not crystallized.