Process for preparation of aromatic thiol

Abstract

The present invention relates to a method for producing aromatic thiols. The method comprises: S1) a step of producing a compound of Formula 2 from a compound of Formula 1; S2) a step of producing a first solution by dissolving the compound of Formula 2 and a catalyst in a halogenated solvent; S3) a step of producing a second solution by adding a reducing agent to the halogenated solvent; S4) a step of producing a product by mixing and reacting the first solution and the second solution at a temperature of 60°C or lower; and S5) a step of separating aromatic thiols from the product. (Chemical Formula 1) [Ar-SO3-1]M (Chemical Formula 2) Ar-SO2-X (In the above chemical formulas 1 and 2, Ar is a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, M is a Group I or Group II metal ion, and X is a halogen element.)

Description

Technology Field

[0001] The present invention relates to a method for producing aromatic thiols. Background Technology

[0002] Thiols are organic sulfur compounds of the 'R-SH' form (where R is an alkyl or other organic substituent) and are called thiols, sulfidrills, or mercaptans. The '-SH' functional group itself is also referred to as a thiol group, sulfidrill group, or sulfanyl group. The presence of various large amounts of thiols produces a strong odor, such as that of garlic or rotten eggs. Due to this characteristic, they are sometimes used as odorants to aid in the detection of odorless gases.

[0003] Aromatic thiols are frequently used as basic starting materials for synthesizing various useful compounds, such as optical materials, pesticides, and pharmaceuticals. Well-known methods for producing aromatic thiols include the Newman-Kwart rearrangement reaction using aromatic alcohols as starting materials and the reduction of sulfonyl chlorides.

[0004] The method for producing aromatic thiols via the Newman-Kwart rearrangement reaction is not widely utilized due to significant disadvantages in terms of productivity, as it requires harsh high-temperature conditions and the use of expensive metal catalysts.

[0005] Meanwhile, the method for producing aromatic thiols through the reduction of sulfonyl chloride is being widely utilized in industrial applications due to its relatively excellent productivity.

[0006] However, as disclosed in Japanese Patent Publication No. 2000-256306, in the case of a conventional method for producing aromatic thiols through the reduction of sulfonyl chloride, a very rapid exothermic reaction is generally generated by the reducing agent during the reduction of sulfonyl chloride, and the sulfonyl chloride is reduced under high temperatures. Consequently, proper temperature control is not maintained during the reduction of sulfonyl chloride, and a large amount of impurities may be generated. Therefore, there is a problem in that it is difficult to reliably produce high-purity products with high yield using the conventional method. Prior art literature

[0007] : Japanese Published Patent Application No. 2000-256306 The problem to be solved

[0008] The objective of the present invention is to provide a method for producing aromatic thiols capable of producing high-purity aromatic thiols with a high conversion rate. means of solving the problem

[0009] A method for producing an aromatic thiol according to one embodiment of the present invention comprises: S1) a step of producing a compound of the following formula 2 from a compound of the following formula 1;

[0010] S2) a step of preparing a first solution by dissolving the compound of Formula 2 and the catalyst in a halogenated solvent; S3) a step of preparing a second solution by adding a reducing agent to the halogenated solvent; S4) a step of preparing a product by mixing and reacting the first solution and the second solution at a temperature of 60°C or lower; and S5) a step of separating an aromatic thiol from the product; comprising.

[0011] (Chemical Formula 1)

[0012] [Ar-SO3 -1 ]M

[0013] (Chemical Formula 2)

[0014] Ar-SO2-X

[0015] In the above chemical formulas 1 and 2, Ar is a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, M is a Group I or Group II metal ion, and X is a halogen element.

[0016] In a method for producing an aromatic thiol according to one embodiment of the present invention, the step S1) may include: S1-1) a step of preparing a reaction solution by mixing the compound of Formula 1, a chlorinating agent, and an amine-based compound in the halogenated solvent; S1-2) a step of obtaining a product by reacting the reaction solution; and S1-3) a step of separating the compound of Formula 2 from the product.

[0017] In a method for producing an aromatic thiol according to one embodiment of the present invention, in step S4), the temperature may be 40 ℃ or lower.

[0018] In a method for producing an aromatic thiol according to one embodiment of the present invention, in step S4), the temperature may be 25 ℃ or lower.

[0019] In a method for producing an aromatic thiol according to one embodiment of the present invention, in step S2), the first solution may comprise 10 to 50 parts by weight of the compound of Formula 2 and 80 to 150 parts by weight of a catalyst per 100 parts by weight of the halogenated solvent.

[0020] In a method for producing an aromatic thiol according to one embodiment of the present invention, in step S3), the reducing agent is a zinc particle and an alkylchlorosilane compound, and the weight ratio of the zinc particle to the alkylchlorosilane compound may be 1:0.5 to 3.

[0021] In a method for producing an aromatic thiol according to one embodiment of the present invention, in step S4), the weight ratio of the first solution to the second solution to be mixed may be 1 to 0.1 to 2.

[0022] In a method for producing an aromatic thiol according to one embodiment of the present invention, in step S4), the mixing may be performed by slowly adding the second solution dropwise to the first solution and stirring.

[0023] In a method for producing an aromatic thiol according to one embodiment of the present invention, the step S5) may comprise: S5-1) a step of filtering the product to remove solid impurities; S5-2) a first purification step of removing liquid impurities by adding a first extraction solvent that is immiscible with the halogenating solvent to the product from which solid impurities have been removed; S5-3) a second purification step of removing liquid impurities by adding a second extraction solvent that is immiscible with the halogenating solvent to the product obtained from the first purification step; and S5-4) a third purification step of removing liquid impurities by adding a third extraction solvent that is immiscible with the halogenating solvent to the product obtained from the second purification step.

[0024] In a method for producing an aromatic thiol according to one embodiment of the present invention, after step S5-4), a fourth purification step may be further included in S5-5) in which an alkane-based solvent is added to the product obtained from the third purification step to remove liquid impurities.

[0025] In a method for producing an aromatic thiol according to one embodiment of the present invention, the first extraction solvent may be a co-solvent of an ether-based solvent and water.

[0026] In a method for producing an aromatic thiol according to one embodiment of the present invention, the second extraction solvent may be a basic aqueous solution.

[0027] In a method for producing an aromatic thiol according to one embodiment of the present invention, the third extraction solvent may be a combination solvent of an ether-based solvent and an acidic aqueous solution. Effects of the invention

[0028] The method for producing aromatic thiols according to the present invention can provide high-purity and high-quality aromatic thiols with low impurity content. Brief explanation of the drawing

[0029] Figure 1 is a graph showing the gas chromatography (GC) results of an aromatic thiol produced through a method for producing an aromatic thiol according to one embodiment of the present invention. Specific details for implementing the invention

[0030] The present invention will be described in detail below with reference to the attached drawings. The drawings presented below are provided as examples to ensure that the concept of the present invention is sufficiently conveyed to those skilled in the art. Accordingly, the present invention is not limited to the drawings presented below and may be embodied in other forms, and the drawings presented below may be exaggerated to clarify the concept of the present invention. Unless otherwise defined, technical and scientific terms used herein shall have the meaning commonly understood by those skilled in the art to which this invention pertains, and descriptions of known functions and configurations that could unnecessarily obscure the essence of the present invention in the following description and attached drawings are omitted.

[0031] Additionally, the singular form used in the specification and the appended claims may be intended to include the plural form unless specifically indicated otherwise in the context.

[0032] In this specification and the appended claims, terms such as "first," "second," etc. are used not in a limiting sense, but for the purpose of distinguishing one component from another.

[0033] In this specification and the appended claims, terms such as "include" or "have" mean that the features or components described in the specification exist, and unless specifically limited, this does not preclude the possibility that one or more other features or components may be added.

[0034] In this specification, "substituent," "radical," "group," "moiety," and "fragment" may be used interchangeably.

[0035] In this specification, "CA-CB" means "having a carbon number of A or more and B or less".

[0036] In this specification, "cycloalkyl" refers to a monovalent saturated or unsaturated carbocyclic radical composed of one or more rings, which is not aromatic. The cycloalkyl comprises a monocyclic or polycyclic group having 3 to 18 carbon atoms and may be further substituted by other substituents. Here, polycyclic means a group directly connected to or condensed with another ring group, or a ring system in the form of a spiro. Here, the other ring group may be a cycloalkyl, but may also be other types of ring groups, such as heterocycloalkyl, aryl, heterocyclic, etc. The number of carbon atoms of the cycloalkyl may be 3 to 18, specifically 3 to 15. Specific examples of cycloalkyl include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0037] In this specification, “heterocycloalkyl” means a substituted or unsubstituted non-aromatic 3 to 15-membered ring radical composed of a carbon atom and 1 to 5 heteroatoms selected from nitrogen, phosphorus, oxygen, and sulfur, and the heterocycloalkyl radical may be a unicyclic, dicyclic, or tricyclic ring system that may be fused, bridged, or include a spiro-ring system, and the nitrogen, phosphorus, carbon, oxygen, or sulfur atoms in the heterocycloalkyl radical may be oxidized to various oxidation states as needed. Additionally, the nitrogen atom may be quaternized as needed. Examples of heterocycloalkyl radicals may include non-aromatic heterocyclic monovalent radicals such as aziridine, pyrrolidine, azetidine, piperidine, tetrahydropyridine, piperazine, morpholine, thiomopoline, 3-azabicyclo[3.1.0]hexane, octahydropyrrolo[3,4-c]pyrrole, 2,7-diazaspiro[4.4]nonane, and 2-azspiro[4.4]nonane.

[0038] In this specification, "aryl" is an organic radical derived from an aromatic hydrocarbon by the removal of one hydrogen, comprising a monocyclic or polycyclic group having 6 to 18 carbon atoms, and may be further substituted by other substituents. Here, polycyclic means a group in which the aryl is directly connected to or condensed with another ring group, or a spiro-cyclic form. Here, the other ring group may be an aryl, but may also be a different type of ring group, such as a cycloalkyl, heterocycloalkyl, heterocyclic, etc. The number of carbon atoms of the aryl may be 3 to 18, specifically 3 to 15. Specific examples of aryls include phenyl, biphenyl, triphenyl, naphthyl, anthryl, chrysenyl, phenanthrenyl, perylenyl, fluoranthenyl, triphenylenyl, phenalenyl, pyrenyl, tetracenyl, pentacenyl, fluorenyl, indenyl, acenaphthylenyl, fluorenyl, and spirofluorenyl, but are not limited to these.

[0039] In this specification, "heteroaryl" refers to an aryl group comprising at least one heteroatom selected from N, O, S, and Se as an aromatic ring backbone atom, wherein the remaining aromatic ring backbone atom is carbon, and is a 5 to 6-membered monocyclic heteroaryl, and a polycyclic heteroaryl condensed with one or more benzene rings, and may be partially saturated. Furthermore, the heteroaryl in the present invention also includes a form in which one or more heteroaryls are connected by a single bond. Specific examples include monocyclic heteroaryls such as furyl, thiophenyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, isoxazolyl, oxazolyl, triazinyl, pyridyl, pyrazinyl, pyrimidinyl, and pyridazinyl; Polycyclic heteroaryls such as benzofuranyl, benzothiophenyl, isobenzofuranyl, benzimidazolyl, benzothiazoyl, benzisothiazolyl, benzoxazolyl, isoindolyl, indolyl, indazoyl, quinolyl, isoquinolyl, dibenzofuranyl, dibenzothiophenyl, carbazoleyl, benzocarbazoleyl, etc., are included but not limited thereto.

[0040] Conventional methods for producing aromatic thiols through the reduction of sulfonyl chlorides have the disadvantage of generating a large amount of impurities due to the reduction of sulfonyl chlorides at high temperatures, as well as causing a very rapid exothermic reaction caused by the reducing agent. Consequently, there is a problem of low productivity due to the relatively low selectivity and conversion rate of aromatic thiols; therefore, a new method for producing aromatic thiols is required that can reliably produce high-purity aromatic thiols with high selectivity and conversion rate.

[0041] In response to these technical requirements, the applicant completed the present invention by conducting further in-depth research on mass production and commercially viable manufacturing methods for thiols, and by discovering that high-purity aromatic thiols can be produced with significantly high conversion rates and selectivity when sulfonyl chloride chlorinated by a specific method is reduced at a relatively low temperature.

[0042] In the following description of the present invention, unless specifically limited otherwise, the aromatic thiol produced from the present invention comprises a compound represented by the following chemical formula 3.

[0043] (Chemical Formula 3)

[0044] Ar-SH

[0045] In the above chemical formulas 1 and 2, Ar is a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl.

[0046] In one embodiment, the cycloalkyl and heterocycloalkyl of Formula 3 may be (C3-C18)cycloalkyl and (C3-18)heterocycloalkyl, and specifically may be (C5-C12)cycloalkyl and (C5-12)heterocycloalkyl.

[0047] In one embodiment, the Ar of the formula 3 may be an aryl or a heteroaryl. Specifically, the aryl or heteroaryl may be a (C6-C20)aryl or a (C5-C20)heteroaryl, more specifically a (C6-C12)aryl or a (C5-C12)heteroaryl.

[0048] In addition, in the present invention, the selectivity, conversion rate, and yield of aromatic thiols are calculated from the following formulas 1 to 3.

[0049] [Formula 1]

[0050] Selectivity (Purity, %) = ((Amount of Aromatic Thiols Generated) / (Total Amount of Product)) × 100

[0051] [Formula 2]

[0052] Conversion Rate (%) = [((Amount of Initial Material Input) - (Amount of Initial Material After Reaction)) / (Amount of Initial Material Input)] × 100

[0053] [Formula 3]

[0054] Yield (%) = (Aromatic thiol conversion rate) × (Aromatic thiol selectivity) × 0.01

[0055] The above selectivity (purity), conversion rate, and yield can be calculated through the amount (moles) measured by gas chromatography.

[0056] The method for producing an aromatic thiol according to the present invention comprises: S1) a step of producing a compound of Formula 2 from a compound of Formula 1; S2) a step of producing a first solution by dissolving the compound of Formula 2 and a catalyst in a halogenated solvent; S3) a step of producing a second solution by adding a reducing agent to the halogenated solvent; S4) a step of producing a product by mixing and reacting the first solution and the second solution at a temperature of 60°C or lower; and S5) a step of separating an aromatic thiol from the product.

[0057] (Chemical Formula 1)

[0058] [Ar-SO3 -1 ]M

[0059] (Chemical Formula 2)

[0060] Ar-SO2-X

[0061] In the above chemical formulas 1 and 2, Ar is a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, M is a Group I or Group II metal ion, and X is a halogen element.

[0062] In one embodiment, the cycloalkyl and heterocycloalkyl of the formulas 1 to 2 may be (C3-C18)cycloalkyl and (C3-18)heterocycloalkyl, and specifically may be (C5-C12)cycloalkyl and (C5-12)heterocycloalkyl.

[0063] In one embodiment, the Ar of Formulas 1 to 2 may be an aryl or heteroaryl. Specifically, the aryl or heteroaryl may be a (C6-C20)aryl or a (C5-C20)heteroaryl, more specifically a (C6-C12)aryl or a (C5-C12)heteroaryl. As an example, the aryl or heteroaryl may be phenyl, 1-naphthyl, 2-naphthyl, furan, benzofuran, thiophene, pyrrole, imidazole, pyrazole, pyridine, pyrimidine, pyrazine, indole, benzimidazole, quinoline, isoquinoline, oxazole, isooxazole, thiazole, benzoxazole, or benzothiazole. The aryl or heteroaryl may be further substituted by other substituents, said substituents may be alkyl groups, halogens, alkoxy groups, alkylthio groups, dialkyl amino groups, or nitro groups. Specifically, said substituents may be (C1-C20) alkyl groups, (C1-C20) alkoxy groups, (C1-C20) alkylthio groups, or (C1-C20) dialkyl amino groups. As a non-limiting example, the alkyl group may be methyl, ethyl, isopropyl, or t-butyl, and the alkoxy group may be methoxy, ethoxy, isopropoxy, or t-butoxy. The alkylthio group may be methylthio, ethylthio, isopropylthio, or t-butylthio, and the dialkyl amino group may be dimethylamino or diethylamino.

[0064] In one embodiment, M of Formula 1 may be a Group I metal ion, and more specifically, M may be a sodium ion (Na + It can be.

[0065] In one embodiment, X of the above chemical formula 1 may be chlorine (Cl).

[0066] The method for producing aromatic thiols according to the present invention involves reducing the compound of Formula 2, which is produced from the compound of Formula 1, to produce an aromatic thiol. Since the reduction reaction can be performed at a low temperature, high-purity, high-quality aromatic thiols with lower impurity content can be produced with high reliability.

[0067] S1) Step is a step of preparing a compound of Formula 2 from a compound of Formula 1. As a non-limiting example, the compound of Formula 1 may be sodium-2-naphthalenesulfonate and the compound of Formula 2 may be 2-naphthalenesulfonyl chloride, but is not limited thereto.

[0068] In one embodiment, step S1) comprises S1-1) a step of preparing a reaction solution by mixing the compound of Formula 1, a chlorinating agent, and an amine-based compound in the halogenated solvent; S1-2) a step of reacting the reaction solution to obtain a product; and S1-3) a step of separating the compound of Formula 2 from the product.

[0069] Specifically, step S1-1) is a step of preparing a reaction solution for chlorinating the compound of Formula 1, and is not particularly limited as long as the method allows each substance to be appropriately mixed. As a non-limiting example, step S1-1) may a) add the compound of Formula 1 to a solvent and stir, b) dropwise add a chlorinating agent to a mixture of the compound of Formula 1 and the solvent, and c) add an amine compound. Such step S1-1) can be performed at room temperature (25±5℃), and the compound of Formula 1, the chlorinating agent, and the amine compound can be added to the halogenated solvent in amounts that minimize the formation of unreacted substances, without being particularly limited.

[0070] For example, with respect to 100 parts by weight of the halogenated solvent, the compound 1 of Formula 1 may be 70 parts by weight or less, 60 parts by weight or less, 50 parts by weight or less, 30 parts by weight or less, 20 parts by weight or less, or 15 parts by weight or less, and may be at least 1 part by weight. More specifically, it may be 1 to 70 parts by weight, 5 to 60 parts by weight, 10 to 50 parts by weight, or 15 to 30 parts by weight.

[0071] In addition, with respect to 100 parts by weight of the halogenated solvent, the chlorinating agent may be 30 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, or 10 parts by weight or less, and may be 1 part by weight or more, without limitation. More specifically, it may be 1 to 30 parts by weight, 3 to 25 parts by weight, 5 to 20 parts by weight, or 10 to 15 parts by weight.

[0072] In addition, with respect to 100 parts by weight of the halogenated solvent, the amine-based compound may be 15 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, or 1.5 parts by weight or less, and may be 0.5 parts by weight or more, without limitation. More specifically, it may be 0.5 to 15 parts by weight, 0.6 to 10 parts by weight, 0.7 to 5 parts by weight, 0.8 to 3 parts by weight, or 0.9 to 1.5 parts by weight.

[0073] In step S1-1), the halogenated solvent may be used without particular limitation as long as it is non-reactive with respect to the compound of Formula 1, the chlorinating agent, and the amine-based compound. Specifically, as an alkylhalogenated solvent, it may be 1,2-dichloroethane in terms of solubility and boiling point.

[0074] The above chlorinating agent and amine-based compound are not particularly limited as long as they can increase the conversion rate from the compound of Formula 1 to the compound of Formula 2, that is, the chlorination conversion rate. Specifically, the chlorinating agent and amine-based compound may form a Vilsmeier reagent. As a non-limiting example, the chlorinating agent may be thionyl chloride (SOCl2) or phosphorus oxychloride (POCl3). Additionally, specifically, the amine-based compound may be an alkylamine-based compound and an N,N-dialkyl-substituted amide compound; as a non-limiting example, it may be N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), or N-methyl-2-pyrrolidone (NMP).

[0075] The reactant prepared in step S1-1) above is reacted through step S1-2) and converted into a product.

[0076] Specifically, step S1-2) is a step of reacting the reactants to form a product, wherein the reaction solution is heated to a temperature at which the reaction solution can react. At this time, the compound of Formula 1 is converted into the compound of Formula 2 through a chlorination reaction. The temperature at which the reaction solution is heated is not particularly limited as long as it is a condition at which the reaction solution can react to form a product. As a non-limiting example, the temperature at which the reaction solution is heated in step S1-2) may be 50°C or higher, 60°C or higher, 70°C or higher, or 80°C or higher, and may be 120°C or lower. More specifically, it may be 50 to 120°C, 60 to 100°C, or 70 to 90°C.

[0077] In the above S1-2) step, the reaction time can be appropriately adjusted according to the amount of reaction solution added, and stirring can be performed until the reaction is finished.

[0078] Step S1-3) above is a step of separating the compound of Formula 2 from the product prepared from Step S1-2).

[0079] Specifically, step S1-3) can be performed by introducing a solvent that is immiscible with the compound of Formula 2 to remove unreacted materials. In step S1-3), the unreacted materials may be the unreacted compound of Formula 1, a chlorinating agent, and an amine-based compound. The solvent that is immiscible with the compound of Formula 2 may be water, as a non-limiting example. Step S1-3) may be repeated two or more times to obtain a high-purity compound of Formula 2 from which the unreacted materials have been removed.

[0080] In step S1-3), the compound of Formula 2 may not undergo a separate powdering step. That is, the product prepared in step S1-3) may be a solution in which the compound of Formula 2 is dissolved in a halogenated solvent. Such a product may be introduced into step S2) as is in the solution state. The concentration of the product may be appropriately controlled through concentration or the additional addition of a halogenated solvent. The controlled final concentration may be 1 to 50 wt%, 2 to 40 wt%, 5 to 30 wt%, or 10 to 25 wt%, but is not limited thereto. As the product is prepared in the solution state in this manner, there is no need to perform a separate process of dissolving the particulate compound of Formula 2 in a solvent. Consequently, not only is the subsequent step S2) easier to perform, but the loss and damage of the compound of Formula 2 can be minimized by not undergoing a powdering process, thereby enabling the production of high-quality aromatic thiols with higher selectivity.

[0081] The product prepared from step S1) as described above, namely the compound of Formula 2, is converted into an aromatic thiol through steps S2) to S6).

[0082] Specifically, steps S2) and S3) are steps for preparing the first solution and the second solution to be used in the reaction, respectively. Steps S2) and S3) may be performed sequentially or simultaneously, or step S3) may precede step S2).

[0083] Step S2) is a step of preparing a first solution by dissolving the compound of Formula 2 and the catalyst in a halogenated solvent. Step S2) can be performed by stirring at room temperature (25±5℃), and the stirring time can be appropriately adjusted according to the amount of the compound of Formula 2, the catalyst, and the halogenated solvent added.

[0084] In one embodiment, as the compound of Formula 2 is provided in a solution state dissolved in a halogenated solvent through step S1-3), step S2) can be performed by introducing the catalyst into the halogenated solvent in which the compound of Formula 2 is dissolved. The amount of each substance introduced in step S2) is not particularly limited as long as it is within a range that minimizes unreacted substances (e.g., the compound of Formula 2) in the subsequent step S5).

[0085] In one embodiment, the first solution of step S2) comprises 10 to 50 parts by weight of the compound of Formula 2 and 80 to 150 parts by weight of a catalyst per 100 parts by weight of the halogenated solvent; specifically, the compound of Formula 2 may be included in the halogenated solvent to satisfy the concentration of step S1-3). The catalyst may comprise 90 to 140 parts by weight or 100 to 135 parts by weight per 100 parts by weight of the halogenated solvent.

[0086] The halogenated solvent in step S2) is the same as the halogenated solvent in step S1) described above, and a detailed description thereof is omitted.

[0087] The above catalyst may be an amide derivative represented by the following chemical formula 3.

[0088] (Chemical Formula 3)

[0089]

[0090] In the above chemical formula 3, R1 is hydrogen, a substituted or unsubstituted alkyl group or aryl group, an alkoxy group, an amino group, an alkyl amino group or a dialkyl amino group, and R2 and R3 may each independently be hydrogen, a substituted or unsubstituted alkyl group, an aryl group or an alkoxy group.

[0091] In a non-limiting specific example, the catalyst may be a chain-type or cyclic amide compound formed from an amine and a carboxylic acid, such as dimethylformamide, N-methylformanilide, dimethylacetamide, or N-methylpiperidone. In addition, it may include chain-type or cyclic urea derivatives or carbamate derivatives, such as tetramethylurea, 1,3-dimethylimidazolidin-2-one, or 3-methyloxazolidin-2-one. More specifically, the catalyst may be dimethylacetamide.

[0092] Step S3) is a step of preparing a second solution that is mixed with S2) in a subsequent step.

[0093] Specifically, step S3) involves adding a reducing agent to a halogenated solvent to prepare a second solution. Step S3) may be performed at a temperature lower than the reaction temperature between the reducing agents to prevent a reaction between the reducing agents. Specifically, step S3) may be performed at a temperature lower than room temperature. More specifically, the temperature at which step S3) is performed may be 20 ℃ or lower, 18 ℃ or lower, 15 ℃ or lower, or 13 ℃ or lower, and may be 4 ℃ or higher, without limitation. More specifically, it may be 4 to 25 ℃, 5 to 20 ℃, 6 to 18 ℃, 7 to 15 ℃, or 8 to 13 ℃.

[0094] Step S3) can also be performed by stirring, and the stirring time can be appropriately adjusted according to the amount of the reducing agent and halogenated solvent added. The amount of each substance added in Step S3) is not particularly limited as long as it is within a range that minimizes unreacted substances (e.g., compounds of Formula 2) in the subsequent Step S5).

[0095] In one embodiment, the second solution of step S3) may contain 80 to 150 parts by weight, 90 to 135 parts by weight, or 100 to 125 parts by weight of a reducing agent per 100 parts by weight of the halogenated solvent.

[0096] The halogenated solvent in step S3) is the same as the halogenated solvent in step S1) described above.

[0097] The reducing agent may be zinc particles and an alkylchlorosilane compound. Specifically, the total amount of zinc particles and the alkylchlorosilane compound introduced in step S3) is not particularly limited as long as it falls within the weight range of the reducing agent introduced into the halogenated solvent described above. However, the weight ratio of the zinc particles to the alkylchlorosilane compound may be 1:0.5 to 3, specifically 1:1 to 2.5, and more specifically 1:1.5 to 2.3. Within this range, the compound of Formula 2 can be converted into an aromatic thiol with an even better conversion rate.

[0098] The zinc particles are not particularly limited as long as they can function as a reducing agent and be easily dispersed in the halogen solvent. Specifically, the zinc particles have an average particle size (D 50 ) may be 100 μm or less, 50 μm or less, 20 μm or less, or 10 μm or less. Non-limitingly, it may be 1 nm or more. More specifically, the zinc particles may be 1 nm to 100 μm, 5 nm to 50 μm, 10 nm to 20 μm, or 15 nm to 10 μm.

[0099] The above average particle size (D50 ) is the average diameter value (D) in particle size distribution measurement according to laser light diffraction method 50 ), that is, the value measured as the particle diameter or median diameter when the cumulative volume reaches 50%.

[0100] The above alkylchlorosilane compound may be chlorotrimethylsilane, bromotrimethylsilane, dichlorodimethylsilane, dichlorodiethylsilane, dichloromethylphenylsilane, dichlorodiphenylsilane, or methyltrichlorosilane.

[0101] Step S4) is a step of preparing a product by mixing and reacting the first solution and the second solution prepared in steps S2) and S3) at a relatively low temperature. In other words, Step S4) is a step of reducing the compound of Formula 2 at a low temperature to form a desired aromatic thiol.

[0102] In step S4), the product comprises the aromatic thiol intended by the present invention, and may include all unreacted materials, catalysts, reducing agents, and intermediate products that are included in the mixture but have not yet reacted. As a non-limiting example, if the compound of Formula 2 is a sulfonyl chloride (Ar-SO2-Cl) compound, the unreacted material may include a sulfonyl chloride (Ar-SO2-Cl) compound, and the intermediate products may include a disulfide (Ar-SS-Ar) compound and a sulfide (Ar-S-Ar) compound. Additionally, if the reducing agent is an alkylchlorosilane compound, the product may further include silane impurities. As a non-limiting example, if the alkylchlorosilane compound is dimethyldichlorosilane, the silane impurities may be dimethylsilanediol, dimethylpolysiloxane, or a mixture thereof.

[0103] The present invention allows for a low-temperature reduction reaction to be performed in step S4), thereby minimizing the amount of the aforementioned intermediate product and enabling the production of aromatic thiols with a high conversion rate.

[0104] Specifically, in step S4), the temperature at which the first solution and the second solution are mixed and reacted may be 50 ℃ or lower, 40 ℃ or lower, 30 ℃ or lower, 25 ℃ or 10 ℃ or lower, and may be 0 ℃ or higher without limitation. More specifically, it may be 0 to 60 ℃, 0 to 50 ℃, 0 to 40 ℃, 5 to 30 ℃ or 5 to 25 ℃. Since step S4) involves the reaction of the first solution and the second solution at a relatively low temperature, high-purity aromatic thiols can be obtained in high yield with almost no intermediate products.

[0105] In one embodiment, step S4) can, of course, be performed by appropriately cooling simultaneously with mixing and reaction so as to prevent the temperature from rising above the temperature range due to the reaction heat generated by the reaction of the first solution and the second solution.

[0106] In step S4) above, the reaction time can be appropriately adjusted according to the amount of the mixture.

[0107] The mixing in step S4) above is not particularly limited as long as it is a method that allows the first solution and the second solution to be properly mixed. As a non-limiting example, the mixing in step S4) can be performed by slowly adding the second solution to the first solvent and stirring under a first temperature condition. Since the second solution is slowly added dropwise to the first solution, such step S4) prevents a rapid reaction, thereby preventing the temperature of the mixture of the first and second solutions from rising rapidly due to the heat of reaction. Consequently, during the mixing and exothermic reaction of the first and second solutions in step S4), the temperature is maintained at a constant level overall, allowing the components of the first and second solutions to react uniformly. Accordingly, aromatic thiols can be produced with a higher yield.

[0108] In one embodiment, in step S4), the weight ratio of the first solution to the second solution being mixed may be 1:0.1 to 2, specifically 1:0.5 to 1.5, more specifically 1:0.6 to 1, but is not limited thereto. However, within the above range, impurities included in the product can be minimized.

[0109] Step S5) above is a step of separating aromatic thiols from the product, and can be performed by removing impurities other than aromatic thiols from the product.

[0110] In one embodiment, the step S5) may include: S5-1) a step of filtering the product to remove solid impurities; S5-2) a first purification step of removing liquid impurities by adding a first extraction solvent that is immiscible with the halogenated solvent to the product from which the solid impurities have been removed; S5-3) a second purification step of removing liquid impurities by adding a second extraction solvent that is immiscible with the halogenated solvent to the product obtained from the first purification step; and S5-4) a third purification step of removing liquid impurities by adding a third extraction solvent that is immiscible with the halogenated solvent to the product obtained from the second purification step. Such a step S5) can prevent the generation of an excessive amount of hydrogen gas due to a reaction between the residual catalyst and water, which is one of the problems of the conventional extraction method through layer separation after adding water, i.e., the water extraction method. In addition, compared to conventional water extraction methods, the phase separation is clear, allowing aromatic thiols to be obtained with a higher yield.

[0111] Specifically, step S5-1) is a step of removing solid impurities, namely zinc particles. Filtration can be performed by conventional methods known in the art. As a non-limiting example, filtration can be performed by removing solid impurities through filter paper to obtain a filtrate (a product from which solid impurities have been removed).

[0112] Step S5-2) is a first purification step, in which a halogenated solvent and a first extraction solvent that is immiscible are added to the product from which solid impurities have been removed, i.e., the filtrate, to remove liquid impurities. As an example, the liquid impurities in Step S5-2) may be the catalyst, unreacted alkylchlorosilane compounds, amide derivatives, and hydrochloric acid.

[0113] Specifically, in step S5-2), a first extraction solvent is added to the filtrate to separate the layers, and the aqueous layer among the separated layers is removed to remove impurities. Since the liquid impurities in step S5-2) are removed using the first extraction solvent, the separation of layers is facilitated, thereby increasing the impurity removal rate.

[0114] In step S5-2), the amount of the first extraction solvent added to the filtrate is not particularly limited. As a non-limiting example, 10 to 100 parts by weight, specifically 20 to 90 parts by weight, and more specifically 30 to 70 parts by weight of the first extraction solvent may be added per 100 parts by weight of the filtrate.

[0115] In one embodiment, the first extraction solvent is not particularly limited as long as it is immiscible with a halogenated solvent, but may be a co-solvent of an ether-based solvent and water which is advantageous for phase separation. The weight ratio of the ether-based solvent to water in the co-solvent is not particularly limited, but may be 1:0.5 to 3, 1:0.8 to 2.5, 1:1 to 2.3, or 1:1.5 to 2. Liquid impurities can be efficiently removed within the above ranges.

[0116] The above ether-based solvent may be selected without limitation as long as it is a solvent that is miscible with water, and examples include dimethyl ether (DME), dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyl tetrahydrofuran, tetrahydrofuran, methyl t-butyl ether (MTBE), or mixtures thereof, but are not limited thereto.

[0117] In one embodiment, step S5-2) can be repeated until the hydrogen ion concentration index (pH) of the filtrate becomes neutral (pH7).

[0118] In one embodiment, step S5-2) may further include a water extraction step performed at least once to neutralize the hydrogen ion concentration index of the filtrate. Specifically, the hydrogen ion concentration index of the filtrate may be neutralized by performing a water extraction step after repeatedly performing an impurity removal process using a first extraction solvent. The water extraction step may be a process of removing impurities by adding water instead of the first extraction solvent of step S5-2) and removing the water layer.

[0119] Step S5-3) is a second purification step, which is a step of further purifying the product obtained from the first purification step, i.e., Step S5-2). Specifically, Step S5-3) can remove by-products, intermediate products, and the halogenated solvent by adding a second extraction solvent that is immiscible with a halogenated solvent to the product obtained from the first purification step. More specifically, Step S5-3) is a step of converting the 'aromatic thiol' contained in the product obtained from Step S5-2) into an 'aromatic thiol salt' through the second extraction solvent, and then separating the layers to remove impurities (by-products, intermediate products, and halogenated solvent) contained in the organic layer and obtaining the 'aromatic thiol salt' contained in the aqueous layer.

[0120] In step S5-3), the second extraction solvent is not particularly limited as long as it is a basic aqueous solution capable of converting aromatic thiols into aromatic thiol salts. As a non-limiting example, the second extraction solvent may be an aqueous sodium hydroxide solution of 1.0 to 4.0 M.

[0121] As such, step S5-3) obtains aromatic thiols from the aqueous layer in a 'salt' state, allowing for the removal of organic impurities with high selectivity, thereby further increasing the impurity removal rate.

[0122] In step S5-3), the amount of the second extraction solvent added to the product obtained from the first purification step is not particularly limited as long as it is an amount capable of producing an aromatic thiol salt, and can be appropriately adjusted according to the concentration of the second extraction solvent added, i.e., the basic aqueous solution. As a non-limiting example, if the second extraction solvent is a sodium hydroxide aqueous solution with a concentration of 5% per 100 parts by weight of the product, 1 to 80 parts by weight, specifically 10 to 70 parts by weight, and more specifically 10 to 50 parts by weight may be added.

[0123] In one embodiment, step S5-3) can be repeated to obtain a sufficient amount of aromatic thiol salt from the aqueous layer.

[0124] In addition, in one embodiment, step S5-3) may further include a step of removing impurities not removed through the ether-based solvent. Specifically, after removing impurities through the second extraction solvent, the remaining impurities not removed may be further removed by adding an ether-based solvent. The step of removing remaining impurities through the ether-based solvent may be a process of removing impurities by adding an ether-based solvent instead of the second extraction solvent of step S5-3) and removing the organic layer.

[0125] Step S5-4) is a third purification step, in which a third extraction solvent that is immiscible with the halogenated solvent is added to the product obtained from the second purification step to remove liquid impurities. Specifically, Step S5-4) is a step of converting the 'aromatic thiol salt' contained in the product obtained from Step S5-3) into 'aromatic thiol' through the third extraction solvent, separating the layers to remove residual impurities contained in the aqueous layer, and obtaining the 'aromatic thiol' contained in the organic layer. The residual impurities may be liquid impurities that were not completely removed in the first purification step.

[0126] In one embodiment, the third extraction solvent is not particularly limited as long as it is capable of converting the aromatic thiol salt into an aromatic thiol. As a specific example, it may be a co-solvent of an ether-based solvent and an acidic aqueous solution that is advantageous for phase separation. The weight ratio of the ether-based solvent to the acidic aqueous solution in the co-solvent is not particularly limited, but may be 1:0.01 to 2, 1:0.05 to 1.5, 1:0.1 to 1, or 1:0.2 to 0.8. Liquid impurities can be efficiently removed within the above range.

[0127] In step S5-4) above, the ether-based solvent may be selected without limitation as long as it is a solvent that is miscible with water, and may be the ether-based solvent exemplified in step S5-2).

[0128] In step S5-4) above, the acidic aqueous solution is an aqueous solution containing a strong acid or a weak acid, and may satisfy a pH of 2 to 6.5. The acidic substance included in the acidic aqueous solution may include hydrochloric acid (HCl), perchloric acid (HClO4), nitric acid (HNO3), sulfuric acid (H2SO4), carbonic acid (H2CO3), or acetic acid (CH3COOH). In one embodiment, the acidic aqueous solution may be an aqueous solution containing hydrochloric acid.

[0129] In step S5-4), the amount of the third extraction solvent added to the product obtained from the second purification step is not particularly limited as long as it is an amount capable of producing aromatic thiols from aromatic thiol salts, and can be appropriately adjusted according to the concentration of the added third extraction solvent, i.e., the co-solvent (ether-based solvent + acidic aqueous solution). As a non-limiting example, if the third extraction solvent is a 10% aqueous hydrochloric acid solution per 100 parts by weight of the product, 10 to 300 parts by weight, specifically 50 to 250 parts by weight, and more specifically 100 to 200 parts by weight may be added.

[0130] In one embodiment, step S5-4) may further include a water extraction step performed at least once to remove an acidic substance introduced into the third extraction solvent. Specifically, step S5-4) may remove an acidic substance by performing an impurity removal process through the third extraction solvent and then performing a water extraction step to remove the acidic substance contained in the third extraction solvent, which is a co-solvent of an ether-based solvent and an acidic aqueous solution. The water extraction step may be a process of removing impurities by adding water instead of the third extraction solvent of step S5-4) and removing the water layer.

[0131] In one embodiment, the method for producing an aromatic thiol may further include a fourth purification step in which an alkane-based solvent is introduced in step S5-5) after step S5-4) to remove liquid impurities. Specifically, the liquid impurities in step S5-5) may be the residual intermediate product.

[0132] Specifically, step S5-5) can be performed by adding and mixing an alkane-based solvent to the product obtained from the third purification step, cooling, and removing the liquid portion. As cooling is performed under an alkane-based solvent in step S6-5), the aromatic thiols in the product are granulated. Subsequently, the liquid portion containing impurities is filtered to obtain high-purity aromatic thiols in granular form.

[0133] In step S5-5), the amount of alkane solvent added to the product is not particularly limited. As a non-limiting example, the alkane solvent may be added to the product in a weight ratio of 1 to 20 times, 2 to 10 times, or 3 to 7 times.

[0134] In one embodiment, the alkane solvent is a (C5-C10)alkane solvent, and as a non-limiting example, it may be heptane.

[0135] Hereinafter, embodiments of the present invention will be described in detail. However, these are presented as examples and are not intended to limit the present invention, and the present invention is defined only by the scope of the claims set forth below.

[0136] <Example 1>

[0137] 1) Step 1: Chlorination reaction

[0138] 50.0 g of solvent 1,2-dichloroethane (DCE) and 10.0 g of sodium-2-naphthalenesulfonate were added to a 3-neck flask equipped with a stirrer and a temperature control device and stirred at room temperature.

[0139] Subsequently, thionyl chloride was added dropwise as a chlorination agent over 30 minutes, and 0.6 g of DMF, an amine compound, was added. Afterward, the temperature was raised to 80 ℃ and stirred for 4 hours.

[0140] Subsequently, 30 g of water was added, and the extraction process was performed twice to remove impurities. The product was recovered by adjusting the concentration to 25% using a DCE solution. The purity of the target product, 2-naphthalenesulfonyl chloride, was confirmed through GC and 1H-NMR analysis, and the yield was determined by solid content analysis. (GC purity > 99.9%, Yield > 98%)

[0141] 2) Step 2: Reduction Reaction

[0142] ①: 38.6 g of the product prepared from 1) above and 44.5 g of dimethylacetamide (DMAc) as a catalyst were added to the first reactor and stirred at room temperature for 30 minutes to prepare the first solution. In addition, 29.0 g of dichloroethane (DCE), 9.7 g of Zn powder, and 19.2 g of dimethyldichlorosilane were added to the second reactor and stirred at 10 ℃ for 30 minutes to prepare the second solution.

[0143] ② : After ①, the first solution was slowly added dropwise and stirred over 4 hours at 10 ℃ to the second reactor containing the second solution, and the reaction was carried out at 10 ℃ for 2 hours. The reaction conversion rate was confirmed by GC analysis. Specifically, it was confirmed by the content of 2-naphthalenesulfonyl chloride, 2-naphthalenesulfide, 2-naphthalenedisulfide, 2-naphthalenethiol, and high-boiling point by-products. The conversion rate was 99.5% or higher.

[0144] ③ : After ②, Zn powder, a solid impurity, was removed by filtration. Then, 43.4 g of methyl t-butyl ether (MTBE) and 43.4 g of water were added to the product from which the solid impurities had been removed, and the extraction process was repeated twice. Subsequently, a water extraction process was performed once. It was confirmed that all acid (HCl) was removed and the pH was neutral.

[0145] Subsequently, 33.4 g of a 5% sodium hydroxide aqueous solution was added to the neutralized product and extracted, and 43.4 g of the MTBE solution was added and extracted to obtain a product containing an aromatic thiol salt.

[0146] Subsequently, the product containing the aromatic thiol salt was introduced into a reactor containing 15.5 g of 10% aqueous hydrochloric acid solution and 43.4 g of MTBE to convert the aromatic thiol salt into an aromatic thiol form. Then, 50 g of water was added to perform the water extraction process twice, and it was confirmed that all the acid (HCl) was removed and the pH was neutral.

[0147] Next, after partially evaporating the MTBE solvent, a heptane solution was added to the product in an amount five times that of the product and cooled to granulate the aromatic thiols, after which the MTBE solvent was completely evaporated and removed. The granulated solid aromatic thiols were obtained, and their purity and conversion rate were measured by GC analysis and are listed in Table 1 below. (GC purity > 99.9%, yield 5.1 g)

[0148] <Example 2>

[0149] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that the temperature of the reactor in ② was set to 25 ℃.

[0150] <Example 3>

[0151] An aromatic thiol was prepared in the same manner as in Example 1, except that the temperature of the reactor in ② above was set to 40 ℃.

[0152] <Example 4>

[0153] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that 37.1 g of dimethylacetamide (DMAc) was added to the first reactor in ① and the temperature of the reactor was set to 40 ℃ in ②.

[0154] <Example 5>

[0155] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that 37.1 g of dimethylacetamide (DMAc) was added to the first reactor and 67.6 g of dichloroethane (DCE) was added to the second reactor in ①, and the temperature of the reactor was set to 60 ℃ in ②.

[0156] <Example 6>

[0157] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that 26.0 g of dimethylacetamide (DMAc) was added to the first reactor and 67.6 g of dichloroethane (DCE) was added to the second reactor in ①, and the temperature of the reactor was set to 60 ℃ in ②.

[0158] <Example 7>

[0159] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that 13.9 g of Zn powder and 27.5 g of dimethyldichlorosilane were added to the second reactor in ①, and the temperature of the reactor was set to 40 ℃ in ②.

[0160] <Comparative Example 1>

[0161] In the above Example 1,

[0162] In the above Example 1, aromatic thiols were prepared in the same manner as in Example 1, except that in ①, 11.1 g of dimethylacetamide (DMAc) was introduced into the first reactor and 165 g of dichloroethane (DCE) was introduced into the second reactor, in ②, the temperature of the reactor was set to 75 ℃, and in ③, aromatic thiols were extracted through a process of adding sodium hydroxide after filtration without neutralizing the pH.

[0163] <Comparative Example 2>

[0164] In the above Example 1,

[0165] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that 11.1 g of dimethylacetamide (DMAc) was introduced into the first reactor and 165 g of dichloroethane (DCE) into the second reactor in ①, and the temperature of the reactor was set to 75 ℃ in ②.

[0166] <Comparative Example 3>

[0167] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that 11.1 g of dimethylacetamide (DMAc) was added to the first reactor and 48.3 g of dichloroethane (DCE) was added to the second reactor in ①, and the temperature of the reactor was set to 75 ℃ in ②.

[0168] <Comparative Example 4>

[0169] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that 18.5 g of dimethylacetamide (DMAc) was added to the first reactor and 48.3 g of dichloroethane (DCE) was added to the second reactor in ①, and the temperature of the reactor was set to 75 ℃ in ②.

[0170] <Comparative Example 5>

[0171] In the above Example 1, an aromatic thiol was prepared in the same manner as in Example 1, except that in ①, 11.1 g of dimethylacetamide (DMAc) was added to the first reactor, 13.9 g of Zn powder and 27.5 g of dimethyldichlorosilane were added to the second reactor, and in ②, the temperature of the reactor was set to 75 ℃.

[0172] Table 1 below shows the conversion rate (%) through GC analysis according to the examples and comparative examples, and Figure 1 shows the graph of the GC analysis results of the product prepared in Example 1. When the conversion rate of 2-naphthalenethiol was less than 70%, it was considered 'process non-conformity' and the purity was not measured.

[0173]

[0174] Referring to Table 1 and Figure 1 above, it was confirmed that the embodiments of the present invention can produce high-purity aromatic thiols in a high yield compared to the comparative examples. In particular, in the case of Examples 1 to 4 and Example 7, where the reaction temperature during reduction was 40°C or lower, the conversion rate of 2-naphthalenethiol was 93% or higher, and in the case of Examples 1 and 2, where the reaction temperature was 25°C or lower, the generation of by-product impurities was suppressed and the conversion rate was high at 99.5% or higher. On the other hand, in the case of the comparative examples, the conversion rate of 2-naphthalenethiol was generally lower than that of the examples, and in particular, in the case of the comparative examples, it was confirmed that the conversion rate of the intermediate product, 2-naphthalene disulfide, was higher than that of 2-naphthalenethiol.

Claims

Claim 1 S1) A step of preparing a compound of the following formula 2 from a compound of the following formula 1; (Formula 1)[Ar-SO3 -1 A method for preparing an aromatic thiol comprising: ]M(Chemical Formula 2)Ar-SO2-XS2) a step of preparing a first solution by dissolving the compound of Chemical Formula 2 and a catalyst in a halogenated solvent; S3) a step of preparing a second solution by adding a reducing agent to the halogenated solvent; S4) a step of preparing a product by mixing and reacting the first solution and the second solution at a temperature of 50°C or lower; and S5) a step of separating an aromatic thiol from the product; wherein, in step S3), the reducing agent is a zinc particle and an alkylchlorosilane compound. (In Chemical Formulas 1 and 2, Ar is a cycloalkyl, heterocycloalkyl, aryl, or heteroaryl, M is a Group I or Group II metal ion, and X is a halogen element.) Claim 2 A method for producing an aromatic thiol according to claim 1, wherein step S1) comprises: S1-1) a step of preparing a reaction solution by mixing the compound of Formula 1, a chlorinating agent, and an amine-based compound in the halogenated solvent; S1-2) a step of reacting the reaction solution to obtain a product; and S1-3) a step of separating the compound of Formula 2 from the product. Claim 3 A method for producing an aromatic thiol according to claim 1, wherein in step S4), the temperature is 40 ℃ or lower. Claim 4 A method for producing an aromatic thiol according to claim 1, wherein in step S4), the temperature is 25 ℃ or lower. Claim 5 A method for producing an aromatic thiol according to claim 1, wherein in step S2), the first solution comprises 10 to 50 parts by weight of the compound of Formula 2 and 80 to 150 parts by weight of a catalyst per 100 parts by weight of the halogenated solvent. Claim 6 A method for producing an aromatic thiol according to claim 1, wherein in step S3), the reducing agent is zinc particles and an alkylchlorosilane compound, and the weight ratio of the zinc particles to the alkylchlorosilane compound is 1:0.5 to 3. Claim 7 A method for producing an aromatic thiol according to claim 1, wherein in step S4), the weight ratio of the first solution to the second solution to be mixed is 1:0.1 to 2. Claim 8 A method for producing an aromatic thiol according to claim 1, wherein in step S4), the mixing is performed by slowly adding the second solution to the first solution dropwise and stirring. Claim 9 A method for producing an aromatic thiol according to claim 1, wherein step S5) comprises: S5-1) a step of filtering the product to remove solid impurities; S5-2) a first purification step of removing liquid impurities by adding a first extraction solvent that is immiscible with the halogenating solvent to the product from which solid impurities have been removed; S5-3) a second purification step of removing liquid impurities by adding a second extraction solvent that is immiscible with the halogenating solvent to the product obtained from the first purification step; and S5-4) a third purification step of removing liquid impurities by adding a third extraction solvent that is immiscible with the halogenating solvent to the product obtained from the second purification step. Claim 10 A method for producing an aromatic thiol according to claim 9, further comprising, after step S5-4), a fourth purification step S5-5) in which an alkane solvent is added to the product obtained from the third purification step to remove liquid impurities. Claim 11 A method for producing an aromatic thiol according to claim 9, wherein the first extraction solvent is a cosolvent of an ether-based solvent and water. Claim 12 A method for preparing an aromatic thiol according to claim 9, wherein the second extraction solvent is a basic aqueous solution. Claim 13 A method for producing an aromatic thiol according to claim 9, wherein the third extraction solvent is a cosolvent of an ether-based solvent and an acidic aqueous solution.

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