Method for producing thiol compound and application of same

Abstract

Disclosed is a method for producing a thiourea compound, the method including reacting an isothiuronium salt (1) in the presence of a compound (2) and at least one selected from the group consisting of a compound (3) and ammonia so as to obtain a compound (4) and a compound (5). R1 represents an n1-valent organic group, n1 represents a number of 1 to 8, R2, R3, and R4 each independently represent a hydrogen atom or a monovalent organic group, X represents a halogen, M1 and M2 each independently represent an alkali metal, an alkaline earth metal, or NH4 +, m represents a number of 1 to 3; n represents a number of 1 to 3; k represents a number of 0 to 3; and q represents an integer of 1 to 2.

Description

Method for producing thiol compounds and their applications

[0001] The present disclosure relates to a method for producing a thiol compound and its application.

[0002] Thiourea and thiol compounds are used as raw materials for thiourethane resins, vulcanization accelerators, and pharmaceuticals. Various studies have been conducted on these thiourea and thiol compounds. For example, Patent Document 1 discloses the following production method for a mercapto ether compound, which allows thiourea to be regenerated and reused when producing a mercapto ether compound from a halogenated ether compound, significantly reduces waste, and improves the purity and yield of the resulting mercapto ether compound. The production method disclosed in Patent Document 1 involves reacting a specific halogenated ether compound with thiourea to obtain an isothiuronium salt, and then decomposing the isothiuronium salt to obtain a mercaptan. The decomposition step involves the regeneration of thiourea by using at least one decomposing agent selected from the group consisting of ammonium hydrogen sulfide, a combination of an ammonium salt and an alkali metal hydrogen chloride, and a combination of hydrogen sulfide and ammonia.

[0003] Patent Document 1: Japanese Unexamined Patent Publication No. 64-38058

[0004] However, when decomposing an isothiuronium salt to obtain thiourea or its derivatives (hereinafter collectively referred to as "thiourea compounds") and mercaptans (hereinafter also referred to as "thiol compounds"), it is sometimes necessary to suppress the generation of gas. This gas is mainly H ２ An object of one aspect of the present disclosure is to provide a method for producing a thiol compound, which can suppress the generation of gas when an isothiuronium salt is decomposed to obtain a thiourea compound and a thiol compound, and applications thereof.

[0005] Means for solving the above problems include the following aspects: <1> A method for producing a thiol compound, comprising a reaction step of reacting an isothiuronium salt (1) represented by the following formula (1) with a sulfur-containing compound (2) represented by the following formula (2) in the presence of a basic compound (3) represented by the following formula (3) and at least one selected from the group consisting of ammonia, to obtain a thiourea compound (4) represented by the following formula (4) and a thiol compound (5) represented by the following formula (5).

[0006]

[0007] In formula (1), formula (4), and formula (5), R １ represents an n1-valent organic group having 1 to 30 carbon atoms, n1 represents an integer of 1 to 8, and R ２ , R ３ , and R ４ each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and X represents a halogen atom. １ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ In formula (3), m represents an integer of 1 to 3, n represents an integer of 1 to 3, and k represents an integer of 0 to 3. ２ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ where p represents an integer of 1 or 2, and q represents an integer of 1 or 2.

[0008] <2> R in the formula (1) and the formula (5) １ is a group containing the following structure (RS1):

[0009]

[0010] In the structure (RS1), each of the eight * marks represents a binding position.

[0011] <3> R in the formula (1) and the formula (5) １a residue obtained by removing at least one mercapto group from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, a residue obtained by removing at least one mercapto group from 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue obtained by removing at least one mercapto group from 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue obtained by removing at least one mercapto group from 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue obtained by removing two mercapto groups from 2,5-bismercaptomethyl-1,4-dithiane, or a residue obtained by removing two mercapto groups from bis(2-mercaptoethyl)sulfide. The method for producing a thiol compound according to <1> or <2>,

[0012] <4> The method for producing a thiol compound according to any one of <1> to <3>, wherein the reaction step comprises carrying out the reaction of the isothiuronium salt (1) under conditions of pH 7 or higher. <5> The method for producing a thiol compound according to any one of <1> to <4>, wherein the reaction step comprises carrying out the reaction of the isothiuronium salt (1) under conditions of 30° C. to 80° C. <6> The method for producing a thiol compound according to any one of <1> to <5>, wherein the reaction step comprises carrying out the reaction of the isothiuronium salt (1) in the presence of the sulfur-containing compound (2), at least one selected from the group consisting of the basic compound (3) and ammonia, and at least one selected from the group consisting of alkali metal sulfites and alkaline earth metal sulfites. <7> The method for producing a thiol compound according to any one of <1> to <6>, comprising, prior to the reaction step, a step of reacting the thiourea compound (4) with a compound (Px) represented by the following formula (Px) to generate the isothiuronium salt (1):

[0013]

[0014] In formula (Px), R Ｘrepresents an n1-valent organic group having 1 to 30 carbon atoms, n1 represents an integer of 1 to 8, and A represents a hydroxy group or a halogen atom. A plurality of A's present in formula (Px) may be the same or different.

[0015] <8> A method for producing a raw material for an optical material containing a thiol compound, the method comprising the step of producing the thiol compound (5) by the method for producing a thiol compound according to any one of <1> to <7>.

[0016] According to one aspect of the present disclosure, there is provided a method for producing a thiol compound, which can suppress gas generation when a thiourea compound and a thiol compound are obtained by reacting an isothiuronium salt, and an application thereof.

[0017] In this disclosure, a numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. In this disclosure, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. In this disclosure, when multiple substances corresponding to each component are present in the composition, the amount of each component in the composition means the total amount of the multiple substances present in the composition, unless otherwise specified. In the numerical ranges described in stages in this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in the numerical ranges described in this disclosure, the upper or lower limit of that numerical range may be replaced with a value shown in the examples.

[0018] [Method for producing thiol compound] The method for producing a thiol compound of the present disclosure includes a reaction step of reacting an isothiuronium salt (1) represented by the following formula (1) with a sulfur-containing compound (2) represented by the following formula (2) in the presence of a basic compound (3) represented by the following formula (3) and at least one selected from the group consisting of ammonia, to obtain a thiourea compound (4) represented by the following formula (4) and a thiol compound (5) represented by the following formula (5). The method for producing a thiol compound of the present disclosure may include other steps as necessary.

[0019]

[0020] In formula (1), formula (4), and formula (5), R １ represents an n1-valent organic group having 1 to 30 carbon atoms, n1 represents an integer of 1 to 8, and R ２ , R ３ , and R ４ each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and X represents a halogen atom. １ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ In formula (3), m represents an integer of 1 to 3, n represents an integer of 1 to 3, and k represents an integer of 0 to 3. ２ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ wherein p represents an integer of 1 or 2, and q represents an integer of 1 or 2.

[0021] In the method for producing a thiol compound of the present disclosure, an isothiuronium salt (1) is reacted in the presence of a sulfur-containing compound (2) and at least one selected from the group consisting of a basic compound (3) and ammonia, thereby obtaining a thiourea compound (4) and a thiol compound (5), and suppressing gas generation. The sulfur-containing compound (2) is believed to contribute to the effect of obtaining the thiourea compound (4) and the thiol compound (5) by the reaction of the isothiuronium salt (1) (see, for example, Examples 1 to 5 and Comparative Examples 2 and 3 described below). Furthermore, the effect of suppressing gas generation is believed to be contributed by at least one selected from the group consisting of a basic compound (3) and ammonia (see, for example, Examples 1 to 5 and Comparative Example 1 described below). This gas is mainly composed of H ２ It is presumed to be S gas.

[0022] The thiourea compound (4) and the thiol compound (5) obtained in the reaction step are both used, for example, as raw materials for optical materials (e.g., lenses). Among these, the thiourea compound (4) is used as a raw material for producing a thiol compound (e.g., thiol compound (5)) as a raw material for optical materials. Furthermore, the isothiuronium salt, which is the starting material in the reaction step, is obtained by reacting the thiourea compound with the compound (Px) described below. From the above, the method for producing a thiol compound according to the present disclosure not only enables the high yield of a thiol compound that is effective as a raw material for optical materials (e.g., lenses), but also contributes to the reuse (recycling) of the thiourea compound.

[0023] Furthermore, in the method for producing a thiol compound of the present disclosure, a thiourea compound, which is one of the reaction products of the isothiuronium salt (1), can be reused, thereby reducing the burden of treating wastewater generated by decomposition. For example, in cases where a thiourea compound is not obtained as a reaction product of the isothiuronium salt (1) and dicyandiamide, for example, is produced as another reaction product, treatment of wastewater containing the resulting dicyanamide (e.g., incineration) is necessary. In the method for producing a thiol compound of the present disclosure, the burden of treating this wastewater can be reduced.

[0024] <Reaction Step> The reaction step in the method for producing a thiol compound of the present disclosure is a step of reacting an isothiuronium salt (1) with a sulfur-containing compound (2) and at least one selected from the group consisting of a basic compound (3) and ammonia in the presence of the isothiuronium salt (1) to obtain a thiourea compound (4) and a thiol compound (5). Each compound in the reaction step will be described below.

[0025] (Isothiuronium Salt (1)) The isothiuronium salt (1) is a starting material in the reaction step and is an isothiuronium salt represented by the following formula (1): In the reaction step, only one type of isothiuronium salt (1) may be used, or two or more types may be used.

[0026]

[0027] In formula (1), R １ represents an n1-valent organic group having 1 to 30 carbon atoms, n1 represents an integer of 1 to 8, and R ２ , R ３ , and R ４ each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and X represents a halogen atom.

[0028] In formula (1), R １ represents an n1-valent organic group having 1 to 30 carbon atoms. １ The number of carbon atoms in the monovalent organic group having 1 to 30 carbon atoms represented by the formula (I) is preferably 1 to 10.

[0029] R １ is preferably a group containing a hydrogen atom, a carbon atom, and a sulfur atom, more preferably a group containing the following structure (RS1), and even more preferably a group containing a mercaptoethylthio group.

[0030]

[0031] In the structure (RS1), each of the eight * marks represents a binding position.

[0032] R １ The molecular weight of the group represented by the formula (I) is preferably 100 to 500, more preferably 150 to 350, and even more preferably 150 to 300.

[0033] R １ is preferably a residue obtained by removing at least one mercapto group from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, a residue obtained by removing at least one mercapto group from 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue obtained by removing at least one mercapto group from 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue obtained by removing at least one mercapto group from 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue obtained by removing at least one mercapto group from 2,5-bismercaptomethyl-1,4-dithiane, or a residue obtained by removing at least one mercapto group from bis(2-mercaptoethyl)sulfide, More preferred are residues in which at least one mercapto group has been removed from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, residues in which at least one mercapto group has been removed from 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, residues in which at least one mercapto group has been removed from 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and residues in which at least one mercapto group has been removed from 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and particularly preferred are residues in which at least one mercapto group has been removed from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane.

[0034] n1 represents an integer of 1 to 8. n1 is preferably an integer of 2 to 8, more preferably an integer of 2 to 4, even more preferably an integer of 3 or 4, and even more preferably 3.

[0035] In formula (1), R ２ , R ３ , and R ４ R each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. ２ , R ３ , or R ４The number of carbon atoms in the monovalent organic group having 1 to 10 carbon atoms represented by R is preferably 1 to 6, and more preferably 1 to 3. ２ , R ３ , or R ４ The monovalent organic group represented by the formula (I) is preferably an aliphatic group which may contain a heteroatom, an alicyclic group which may contain a heteroatom, or an aromatic group which may contain a heteroatom, more preferably an alkyl group, and even more preferably a methyl group or an ethyl group.

[0036] R ２ , R ３ , and R ４ are each independently preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms (more preferably 1 to 6, and even more preferably 1 to 3), more preferably a hydrogen atom, a methyl group, or an ethyl group, and even more preferably a hydrogen atom.

[0037] In formula (1), X represents a halogen atom. The halogen atom represented by X is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and more preferably a chlorine atom.

[0038] (Sulfur-containing compound (2)) The sulfur-containing compound (2) is a compound represented by the following formula (2): In the reaction step, only one type of sulfur-containing compound (2) may be used, or two or more types may be used.

[0039]

[0040] In formula (2), M １ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ wherein m represents an integer of 1 to 3, n represents an integer of 1 to 3, and k represents an integer of 0 to 3.

[0041] In formula (2), M １ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ Represents.

[0042] M １ The alkali metal atom represented by the formula (I) is preferably a Li atom, a Na atom, or a K atom, and more preferably a Na atom.

[0043] M １ The alkaline earth metal atom represented by the formula (I) is preferably a Mg atom or a Ca atom.

[0044] M １ is preferably an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ and more preferably an alkali metal atom, further preferably a Li atom, a Na atom, or a K atom, and further preferably a Na atom.

[0045] In formula (2), m represents an integer of 1 to 3. m is preferably 1 or 2, and more preferably 1.

[0046] In formula (2), n represents an integer of 1 to 3. n is preferably 1 or 2, and more preferably 1.

[0047] In formula (2), the sum of m and n is preferably 2 or 3.

[0048] In formula (2), k represents an integer of 0 to 3. k is preferably an integer of 0 to 2, and more preferably 0 or 1.

[0049] Specific examples of the sulfur-containing compound (2) include NaSH, Na ２ S., K.S.H., K. ２ S, Ca(SH) ２ , CaS, Li ２ S, LiSH, (NH ４ ) ２ S, (NH ４ ) SH, etc.

[0050] The amount of sulfur-containing compound (2) charged is preferably 90 mol % to 200 mol % based on the amount of isothiuronium base in isothiuronium salt (1). In the present disclosure, the isothiuronium base in isothiuronium salt (1) refers to the group in parentheses in formula (1), of which n1 is present in formula (1).

[0051] In the reaction step, it is preferable to use an aqueous solution of the sulfur-containing compound (2). The concentration of the aqueous solution can be appropriately adjusted.

[0052] (At least one selected from the group consisting of basic compound (3) and ammonia) In the reaction step, a basic compound (3) and ammonia (NH ３ At least one selected from the group consisting of: The basic compound (3) is a compound represented by the following formula (3): When the basic compound (3) is used, only one kind or two or more kinds of the basic compound (3) may be used.

[0053]

[0054] In formula (3), M ２ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ wherein p represents an integer of 1 or 2, and q represents an integer of 1 or 2.

[0055] M ２ The alkali metal atom represented by the formula (I) is preferably a Li atom, a Na atom, or a K atom, and more preferably a Na atom.

[0056] M ２ The alkaline earth metal atom represented by the formula (I) is preferably a Mg atom or a Ca atom.

[0057] M ２ is preferably an alkali metal atom or NH ４ ＋ and more preferably a Na atom or NH ４ ＋ is.

[0058] In formula (3), p represents an integer of 1 or 2. Preferably, p is 1.

[0059] In formula (3), q represents an integer of 1 or 2. q is preferably 1.

[0060] Specific examples of the basic compound (3) include NaOH, NH ４ OH (i.e., aqueous ammonia), etc.

[0061] Basic compound (3) and ammonia (NH ３The total amount of the isothiuronium salts (1) is preferably 10 mol % to 200 mol % based on the amount of isothiuronium base in the isothiuronium salt (1).

[0062] When the basic compound (3) is used in the reaction step, it is preferable to use an aqueous solution of the basic compound (3). The concentration of the aqueous solution can be appropriately adjusted.

[0063] (Basic Compound Other Than Sulfur-Containing Compound (2) and Basic Compound (3)) In the reaction step, a basic compound other than the sulfur-containing compound (2) and the basic compound (3) may be used, if necessary. Examples of such compounds include sodium bicarbonate, sodium bicarbonate, potassium bicarbonate, potassium bicarbonate, and calcium carbonate. When a basic compound is used in the reaction step, it is preferable to use an aqueous solution of the compound. The concentration of the aqueous solution can be adjusted as appropriate.

[0064] (Thiourea Compound (4)) The thiourea compound (4) is one of the compounds obtained by the reaction of the isothiuronium salt (1), and is a compound represented by the following formula (4). As described above, the thiourea compound (4) is a compound obtained by the reaction of the sulfur-containing compound (2), the basic compound (3), and ammonia (NH ３ The isothiuronium salt (1) is reacted with at least one selected from the group consisting of (a) and (b) in the presence of (c), to obtain a thiourea compound (4) as one of the reaction products.

[0065]

[0066] In formula (4), R ２ , R ３ , and R ４ each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms. ２ , R ３ , and R ４ are R in formula (1), respectively. ２ , R ３ , and R ４ The same applies to the preferred embodiments.

[0067] In the present disclosure, the term "thiourea compound" refers to a compound represented by formula (4),２ , R ３ , and R ４ are both hydrogen atoms) and derivatives thereof (i.e., compounds in which R ２ , R ３ , and R ４ and at least one of the groups is a monovalent organic group having 1 to 10 carbon atoms.

[0068] In the reaction step, only one type of thiourea compound (4) may be obtained, or two or more types may be obtained.

[0069] (Thiol Compound (5)) Thiol compound (5) is another compound obtained by the reaction of isothiuronium salt (1), and is a compound represented by the following formula (4). Thiol compound (5), which is one of the reaction products of isothiuronium salt (1), is obtained by reacting basic compound (3) and ammonia (NH ３ However, it can also be produced when the isothiuronium salt (1) is reacted in the absence of at least one selected from the group consisting of basic compounds (3) and ammonia (NH ３ By reacting the isothiuronium salt (1) in the presence of at least one selected from the group consisting of:

[0070]

[0071] In formula (5), R １ represents an n1-valent organic group having 1 to 30 carbon atoms, and n1 represents an integer of 1 to 8. １ and n1 are R in formula (1), １ and n1, and preferred embodiments are also the same.

[0072] In the reaction step, only one type of thiol compound (5) may be obtained, or two or more types may be obtained. The thiol compound (5) is preferably polythiol component A1 which is 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane; polythiol component A2 which is at least one selected from the group consisting of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane; 2,5-bismercaptomethyl-1,4-dithiane; or bis(2-mercaptoethyl) sulfide; polythiol component A1 or polythiol component A2 are more preferred, and polythiol component A1 is particularly preferred.

[0073] (Addition Method of Isothiuronium Salt (1), Sulfur-Containing Compound (2), and "At Least One Selected from the Group Consisting of Basic Compound (3) and Ammonia") In the reaction step, the addition method of the isothiuronium salt (1), sulfur-containing compound (2), and "at least one selected from the group consisting of basic compound (3) and ammonia" is not particularly limited and can be selected appropriately. Examples of the addition method include the following Addition Methods 1 to 4. (Addition Method 1) A reactor is charged with an isothiuronium salt reaction mass (hereinafter also referred to as "ITU salt mass"), and then sulfur-containing compound (2) and "at Least One Selected from the Group Consisting of Basic Compound (3) and Ammonia" (hereinafter also simply referred to as "base") are added thereto (corresponding to Addition Method (1) in the Examples). (Addition Method 2) A reactor is charged with the sulfur-containing compound (2) and a base, and then ITU salt mass is added thereto (corresponding to Addition Method (2) in the Examples). (Addition Method 3) A base is charged into a reactor, and then a sulfur-containing compound and an ITU salt mass are added thereto. (Addition Method 4) A sulfur-containing compound, a base, and an ITU salt mass are simultaneously added dropwise to a reactor. In the above Addition Methods 1 to 3, a portion of each component may be charged into the reactor, and the remainder may be added later. Furthermore, in Addition Method 1, the base may be added in portions. In this case, the bases added in portions may be the same or different. An example of adding the base in portions in Addition Method 1 is, for example, first, an ITU salt mass and a portion of the base to be used (e.g., NaOH) are charged into a reactor, and then the sulfur-containing compound (2) and the remainder of the base to be used (e.g., NH ４ OH) is added.

[0074] (Reaction Solvent (Organic Solvent)) The reaction in the reaction step may be carried out in the presence of a reaction solvent or in the absence of a reaction solvent (i.e., under conditions in which no reaction solvent is present). Here, the reaction solvent means an organic solvent (e.g., toluene). The reaction in the reaction step is preferably carried out in the absence of a reaction solvent.

[0075] (At least one selected from the group consisting of alkali metal sulfites and alkaline earth metal sulfites) In the reaction step, as described above, the isothiuronium salt (1) is reacted in the presence of a sulfur-containing compound (2) and at least one selected from the group consisting of a basic compound (3) and ammonia. In the reaction step, the isothiuronium salt (1) may be reacted in the presence of the sulfur-containing compound (2), at least one selected from the group consisting of a basic compound (3) and ammonia, and another basic compound. From the viewpoint of more effectively obtaining the effects of the thiol compound production method of the present disclosure, it is preferable to react the isothiuronium salt (1) in the presence of at least one selected from the group consisting of a sulfur-containing compound (2), a basic compound (3), and ammonia, and at least one selected from the group consisting of an alkali metal sulfite and an alkaline earth metal sulfite (hereinafter, these are also collectively referred to as "specific sulfites").

[0076] The amount of the specific sulfite to be added is preferably 0.1 mol % to 10 mol %, more preferably 1 mol % to 8 mol %, based on the amount of the isothiuronium salt (1) to be added.

[0077] The specific sulfite may be added to the aqueous NaSH solution in advance.

[0078] The timing of adding the specific sulfite is preferably as follows: For example, in the case of the above-mentioned Method 1, it is preferable to charge an isothiuronium salt reaction mass (hereinafter also referred to as "ITU salt mass") into a reactor, then add the sulfur-containing compound (2) and a base dropwise thereto, and then add the specific sulfite (see Example 1 described below). Also, in the case of the above-mentioned Method 2, it is preferable to charge the sulfur-containing compound (2), a base, and the specific sulfite into a reactor, then add the ITU salt mass dropwise thereto (see Example 2 described below).

[0079] (Preferred pH) The reaction step preferably includes carrying out the reaction of the isothiuronium salt (1) under conditions of pH 7 or higher (preferably pH 7 to pH 14). This allows the effects of the method for producing a thiol compound of the present disclosure to be more effectively exhibited.

[0080] In this disclosure, pH refers to the pH at 25° C. unless otherwise specified.

[0081] (Preferred Reaction Temperature) The reaction step preferably includes carrying out the reaction of the isothiuronium salt (1) under conditions of 30° C. to 80° C. (preferably 40° C. to 70° C.), thereby more effectively achieving the effects of the method for producing a thiol compound of the present disclosure.

[0082] (Preferable Reaction Time) In the reaction step, the reaction of the isothiuronium salt (1) is preferably carried out for 0.3 to 10 hours (preferably 1 to 5 hours).

[0083] (Reaction mixture, separation of target product) In the reaction step, the isothiuronium salt (1) may be reacted in the presence of a sulfur-containing compound (2) and at least one selected from the group consisting of a basic compound (3) and ammonia to obtain a reaction mixture containing a thiourea compound (4) and a thiol compound (5). The reaction mixture may contain components other than the thiourea compound (4) and the thiol compound (5) (e.g., unreacted raw materials, reaction by-products, etc.).

[0084] A known method can be appropriately applied to separate the target product (thiol compound (5)) from the reaction mixture. For example, a method can be applied in which the reaction mixture is allowed to stand, separated into an organic layer containing thiol compound (5) and an aqueous layer containing thiourea compound (4), and thiol compound (5) is separated from the resulting organic layer. The thiol compound (5) can be separated from the organic layer by an appropriate combination of conventional methods such as acid washing, water washing, distillation, and filtration.

[0085] When the thiourea compound is separated from the aqueous layer, the separation method is not particularly limited, and a suitable combination of conventional methods can be applied.

[0086] <Step of generating isothiuronium salt (1)> The method for producing a thiol compound of the present disclosure may include, prior to the above-described reaction step, a step of reacting a thiourea compound (4) with a compound (Px) represented by the following formula (Px) to generate an isothiuronium salt (1) (hereinafter also referred to as a "step of generating an isothiuronium salt (1)").

[0087]

[0088] In formula (Px), R Ｘ represents an n1-valent organic group having 1 to 30 carbon atoms, n1 represents an integer of 1 to 8, and A represents a hydroxy group or a halogen atom. A plurality of A's present in formula (Px) may be the same or different.

[0089] R in formula (5) Ｘ and n1 are R in formula (1), １ and n1 have the same meanings as n1 and n2, and preferred embodiments are also the same. Ｘ and R in formula (1) １ and may be the same or different.

[0090] In formula (Px), a plurality of A's each independently represent a hydroxy group or a halogen atom.

[0091] In the step of producing the isothiuronium salt (1), the thiourea compound (4) may be reacted with two or more compounds (Px).

[0092] According to an embodiment including the step of producing an isothiuronium salt (1), the thiourea compound (4) consumed in the step of obtaining the isothiuronium salt (1) can be regenerated by the reaction of the isothiuronium salt (1) in the reaction step. The regenerated thiourea compound (4) can be isolated by a known method and, if necessary, can be reused together with unreacted thiourea compound (4) in the production of a thiol compound.

[0093] [Method for producing raw material for optical material] The method for producing a raw material for optical material according to the present disclosure is a method for producing a raw material for optical material containing a thiol compound, and includes a step of producing a thiol compound (5) by the method for producing a thiol compound according to the present disclosure described above.

[0094] Examples of optical materials in the raw materials for optical materials include lenses (e.g., eyeglass lenses, camera lenses, polarized lenses), light-emitting diodes (LEDs), and the like. The raw materials for optical materials contain the above-described thiol compound (5). By using the raw materials for optical materials containing the thiol compound (5), a thiourethane resin can be produced. The obtained thiourethane resin can be processed, such as by cutting or polishing, as necessary, to produce an optical material.

[0095] The raw material for optical materials may be a raw material consisting only of the above-mentioned thiol compound (5), or may contain other components as necessary. In this case, the method for producing a raw material for optical materials of the present disclosure may include a step of mixing the produced thiol compound (5) with other components.

[0096] Examples of other components include blue ink agents such as polyiso(thio)cyanate compounds, polymerization catalysts, internal mold release agents, resin modifiers, chain extenders, crosslinking agents, radical scavengers, light stabilizers, ultraviolet absorbers, antioxidants, oil-soluble dyes, fillers, adhesion improvers, antibacterial agents, antistatic agents, dyes, fluorescent brighteners, fluorescent pigments, and inorganic pigments.

[0097] Examples of the present disclosure are shown below, but the present disclosure is not limited to the following examples. Unless otherwise specified, "%" and "ppm" mean "% by mass" and "ppm by mass", and pH means pH at 25°C.

[0098] [HPLC Analysis Conditions] In the present example, the HPLC (High Performance Liquid Chromatography) analysis conditions for the thiourea compounds and the thiol compounds were as follows.

[0099] - HPLC analysis conditions for thiourea compounds - Model: Shimadzu HPLC Detector: SPD-10Avp Pump: LC-10ADvp Thermostat: CTO-10Avp Column: Mightysil RP-18 Aqua 250-4.6 (5 μm) Mobile phase: 0.1 mol-KH ２ P.O. ４Aqueous solution adjusted to pH 3 with phosphoric acid. Flow rate: 0.9 mL / min. Thermostat: 40°C. Detector: UV 220 nm.

[0100] - HPLC analysis conditions for thiol compounds - Model: Shimadzu HPLC Detector: SPD-10Avp Pump: LC-10ADvp Thermostat: CTO-10Avp Column: Mightysil RP-18 GP 150-6.0 (5 μm) CICA-Reagent Mobile phase: Acetonitrile: 0.01 M KH ２ P.O. ４ Aqueous solution = 6:4 Flow rate: 1.0 mL / min Thermostat: 40°C Detector: UV 230 nm

[0101] [Production Example 1] <Production of Isothiuronium Salt (1-1)> In Production Example 1, isothiuronium salt (1-1) was produced as isothiuronium salt (1). Details are provided below. A reactor was charged with 184.4 parts by mass of 2-mercaptoethanol and 29.4 parts by mass of degassed water (dissolved oxygen concentration 2 ppm). Next, 158.6 parts by mass of a 30.5% by mass aqueous sodium hydroxide solution was added dropwise over 30 minutes at 12 to 35°C, and then 110.8 parts by mass of epichlorohydrin was added dropwise over 3 hours at 29 to 36°C, followed by stirring for 1 hour. This yielded an aqueous solution containing compound (Px-1) as compound (Px).

[0102] The structure of compound (Px-1) is as follows: The production of compound (Px-1) was confirmed by NMR.

[0103]

[0104] Next, 498.7 parts by mass of 35% hydrochloric acid was charged into the reactor containing the aqueous solution containing the compound (Px-1), and then 275.3 parts by mass of thiourea as the thiourea compound (4) with a purity of 99.30% was charged, followed by stirring for 3 hours under reflux at 110°C to carry out an isothiuronium salt reaction. This yielded an aqueous solution of isothiuronium salt (1-1) as the isothiuronium salt (1).

[0105] The structure of the isothiuronium salt (1-1) is as follows: The production of the isothiuronium salt (1-1) was confirmed by NMR.

[0106]

[0107] Example 1 NaSH + NaOH, toluene used as reaction solvent, addition method (1), no sulfite A reactor was charged with 1,158.6 g of the aqueous solution of isothiuronium salt (1-1) obtained in Production Example 1 and 448.3 g of toluene, to which 144.7 parts by mass of 30.4% by mass aqueous sodium hydroxide and 505.5 parts by mass of 48.8% by mass aqueous sodium hydrogen sulfide were added (addition method (1)). The resulting liquid was reacted by stirring at 54°C to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0108] Here, sodium hydrogen sulfide (NaSH) is an example of the sulfur-containing compound (2) (specifically, in formula (2), M １ is a sodium atom, and m, k, and n are all 1), and sodium hydroxide (NaOH) is an example of the basic compound (3) (specifically, in formula (3), M ２ is a sodium atom, and p and q are both 1).

[0109] (Evaluation of Gas Generation Inhibition) During the reaction of the isothiuronium salt (1-1), whether or not gas was generated was visually observed, and the gas generation inhibition was evaluated according to the following evaluation criteria. The results are shown in Table 1. In the following evaluation criteria, the ranks of gas generation inhibition are A and B. The gas generated here is mainly H ２ It is presumed to be S gas. - Evaluation criteria for gas generation suppression - A... No gas was generated, and gas generation was suppressed. B... A small amount of gas was generated, but it was an amount that did not cause problems in terms of handling and operation, and gas generation was suppressed. C... A large amount of gas was generated that caused problems in terms of handling or operation, and gas generation could not be suppressed.

[0110] The aqueous layer and the organic layer obtained above were each subjected to the following treatment and analysis.

[0111] (Analysis of Aqueous Layer and Confirmation of Formation of Thiourea Compound (4)) High performance liquid chromatography (HPLC) confirmed that the aqueous layer contained thiourea as the thiourea compound (4).

[0112] Table 1 shows whether or not a thiourea compound (4) (thiourea in this example) was produced by the reaction of the isothiuronium salt (1-1). Specifically, when the content of thiourea in the aqueous layer was greater than the content of unreacted thiourea in the aqueous solution of isothiuronium salt (1-1) obtained in Production Example 1 used in Example 1, the production of thiourea compound (4) was judged to be "present," and when there was no increase, the production of thiourea compound (4) was judged to be "absent."

[0113] (Treatment and Analysis of Organic Layer, and Confirmation of Production of Thiol Compound (5)) The organic layer was acid-washed with 227 parts by mass of 35% by mass aqueous hydrochloric acid at 35°C to 43°C for 2 hours, then washed with 227 parts by mass of degassed water (dissolved oxygen concentration 2 ppm) at 35°C to 45°C for 15 minutes, then washed with 227 parts by mass of 0.1% by mass aqueous ammonia for 15 minutes, and then washed twice with 227 parts by mass of degassed water (dissolved oxygen concentration 2 ppm) at 35°C to 45°C for 15 minutes. From the organic layer after the above-mentioned washing, the solvent was distilled off under heating and reduced pressure, and trace amounts of water were removed under heating and reduced pressure. After that, the mixture was filtered under reduced pressure using a 3 μm PTFE-type membrane filter to obtain a polythiol composition containing thiol compound (5-1) as a main component as thiol compound (5). Here, the thiol compound (5-1) is the above-mentioned polythiol component A1 (ie, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane).

[0114] Table 1 shows whether or not a thiol compound (5) (thiol compound (5-1) in this example) was produced by the reaction of the isothiuronium salt (1-1). The production of the thiol compound (5) was confirmed by HPLC.

[0115] Example 2 NaSH + NaOH, toluene used as reaction solvent, addition method (2), sulfite present A reactor was charged with 144.7 parts by mass of 30.4% by mass aqueous sodium hydroxide, 505.5 parts by mass of 48.8% by mass aqueous sodium hydrogen sulfide, 5.8 parts by mass of sodium sulfite, and toluene (448.3 g), and then the aqueous solution (1158.6 g) of isothiuronium salt (1-1) obtained in Production Example 1 was charged thereto over 35 minutes (addition method (2)). The resulting liquid was reacted by stirring at 54°C to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0116] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0117] [Example 3] <<NaSH + NH ４ OH, toluene used as reaction solvent, addition method (2), sulfite present≫ 118.2 parts by mass of 25.2% by mass aqueous ammonia, 385.1 parts by mass of 48.2% by mass aqueous sodium hydrogen sulfide, 4.2 parts by mass of sodium sulfite, and toluene (448.3 g) were placed in a reactor, and then the aqueous solution of isothiuronium salt (1-1) (1158.6 g) obtained in Production Example 1 was added thereto over 12 minutes (addition method (2)). The resulting liquid was stirred at 54°C to 62°C for 3 hours to carry out a reaction, and then allowed to stand to separate into an aqueous layer and an organic layer. Here, aqueous ammonia (NH ４ OH) is an example of the basic compound (3) (specifically, in formula (3), M ２ NH ４ ＋ and p and q are both 1.

[0118] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0119] Example 4 NaSH+NaOH, No Reaction Solvent, Addition Method (2), Presence of Sulfite A reactor was charged with 379.9 parts by mass of 30.0% by mass aqueous sodium hydroxide, 385.2 parts by mass of 48.2% by mass aqueous sodium hydrogen sulfide, and 4.2 parts by mass of sodium sulfite, and then the aqueous solution (1,158.6 g) of the isothiuronium salt (1-1) obtained in Production Example 1 was added thereto over 20 minutes. The resulting liquid was reacted by stirring at 54°C to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0120] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0121] [Example 5] <<NaSH + NH ４ OH, no reaction solvent, addition method (2), sulfite present≫ A reactor was charged with 147.9 parts by mass of 25.2% by mass ammonia water, 385.2 parts by mass of a 48.2% by mass aqueous solution of sodium hydrogen sulfide, and 4.2 parts by mass of sodium sulfite, and then the aqueous solution (1,158.6 g) of the isothiuronium salt (1-1) obtained in Production Example 1 was charged thereto over 15 minutes (addition method (2)). The resulting liquid was reacted by stirring at 54°C to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0122] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0123] [Example 6] <<NaSH + Na ２ CO ３, NaOH, toluene used as a reaction solvent, addition method (1), no sulfite >> A reactor was charged with 1,158.6 g of the aqueous solution of isothiuronium salt (1-1) obtained in Production Example 1 and 448.3 g of toluene, and then 548.9 parts by mass of a 33.7% by mass aqueous solution of sodium hydrogen sulfide, 144.7 parts by mass of a 30.4% by mass aqueous solution of sodium hydroxide, and 94.9 parts by mass of a 24.5% by mass aqueous solution of sodium carbonate (all of which is addition method (1)). The resulting liquid was reacted by stirring at 54 to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0124] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0125] Comparative Example 1 <<NaSH, basic compound (3) not included, toluene used as reaction solvent, addition method (1), sulfite not included>> A reactor was charged with 1,158.6 g of the aqueous solution of isothiuronium salt (1-1) obtained in Production Example 1 and 448.3 g of toluene, and then 580.7 parts by mass of a 48% by mass aqueous solution of sodium hydrogen sulfide was added thereto. At this time, the generation of hydrogen sulfide was observed. The resulting liquid was reacted by stirring at 54 to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0126] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0127] Comparative Example 2 (No sulfur-containing compound (2), toluene used as reaction solvent, addition method (1), no sulfite) A reactor was charged with 1,158.6 g of the aqueous solution of isothiuronium salt (1-1) obtained in Production Example 1 and 448.3 g of toluene, and then 334.5 parts by mass of 25.2% by mass aqueous ammonia was added thereto. The resulting liquid was reacted by stirring at 54°C to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0128] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0129] Comparative Example 3 (No sulfur-containing compound (2), No reaction solvent, Addition method (1), No sulfite) A reactor was charged with the aqueous solution (1158.6 g) of the isothiuronium salt (1-1) obtained in Production Example 1, and then 368.1 parts by mass of 25.2% by mass aqueous ammonia was added thereto. The resulting liquid was reacted by stirring at 54°C to 62°C for 3 hours, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0130] The aqueous layer and the organic layer obtained above were each treated and analyzed in the same manner as in Example 1. Furthermore, the inhibition of gas generation was evaluated, and the production of thiourea compound (4) and thiol compound (5) was confirmed in the same manner as in Example 1. The results are shown in Table 1.

[0131]

[0132] As shown in Table 1, in Examples 1 to 6, in which isothiuronium salt (1) was reacted in the presence of sulfur-containing compound (2) and at least one selected from the group consisting of basic compound (3) and ammonia, thiourea compound (4) and thiol compound (5) were produced, and gas generation was suppressed. In contrast, in Comparative Example 1, in which basic compound (3) and ammonia were not used, thiourea compound (4) and thiol compound (5) were produced, but gas generation could not be suppressed. In Comparative Examples 2 and 3, in which sulfur-containing compound (2) was not used, thiol compound (5) was produced, but thiourea compound (4) was not produced.

[0133] The above is an example of producing thiol compound (5-1) (i.e., polythiol component A1; 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane) as thiol compound (5). Next, an example of producing thiol compound (5-2) as thiol compound (5) is shown. Here, thiol compound (5-2) is the aforementioned polythiol component A2 (i.e., at least one selected from the group consisting of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane).

[0134] [Production Example 2] <Production of Isothiuronium Salt (1-2)> In Production Example 2, isothiuronium salt (1-2) was produced as isothiuronium salt (1). Details are provided below. A reactor was charged with 89.25 parts by mass of 2-mercaptoethanol, 44.61 parts by mass of degassed water (dissolved oxygen concentration 2 ppm), and 0.58 parts by mass of a 31% by mass aqueous sodium hydroxide solution. Next, 107.68 parts by mass of epichlorohydrin was added dropwise to the reactor at 9°C to 11°C over 4.5 hours, followed by stirring for 1 hour. NMR data confirmed the production of 1-chloro-3-(2-hydroxyethylthio)-2-propanol. Next, 262.30 parts by mass of a 17.3% by mass aqueous sodium sulfide solution was added dropwise to the reactor at 7°C to 37°C over 1 hour, followed by stirring for 3 hours. As a result, an aqueous solution containing the compound (Px-2) as the compound (Px) was obtained.

[0135] The structure of compound (Px-2) is as follows: The production of compound (Px-2) was confirmed by NMR.

[0136]

[0137] Next, 484.6 parts by mass of 35% hydrochloric acid was charged into the reactor containing the aqueous solution containing the compound (Px-2), and then 214 parts by mass of thiourea as the thiourea compound (4) with a purity of 99.90% was charged, followed by stirring for 3 hours under reflux at 110°C to carry out an isothiuronium salt reaction. This yielded an aqueous solution of isothiuronium salt (1-2) as the isothiuronium salt (1).

[0138] The isothiuronium salt (1-2) is at least one selected from the group consisting of the following three compounds: The production of the isothiuronium salt (1-2) was confirmed by NMR.

[0139]

[0140] Example 101 NaSH + NaOH, toluene used as reaction solvent, addition method (1), no sulfite A reactor was charged with 1,203.0 g of the aqueous solution of isothiuronium salt (1-2) obtained in Production Example 2 and 373 g of toluene, to which 191.2 parts by mass of 25.4% by mass aqueous sodium hydroxide and 271.7 parts by mass of 48.0% by mass aqueous sodium hydrogen sulfide were added (addition method (1)). The resulting liquid was reacted by stirring at 54°C to 62°C for 1 hour, and then allowed to stand to separate into an aqueous layer and an organic layer.

[0141] As described in Example 1, sodium hydrogen sulfide (NaSH) is an example of the sulfur-containing compound (2), and sodium hydroxide (NaOH) is an example of the basic compound (3).

[0142] (Evaluation of Gas Generation Inhibition) In the same manner as in Example 1, whether gas was generated during the reaction of the isothiuronium salt (1-2) was visually observed, and the gas generation inhibition was evaluated according to the same evaluation criteria as in Example 1. The results are shown in Table 2.

[0143] The aqueous layer and the organic layer obtained above were each subjected to the following treatment and analysis.

[0144] (Analysis of Aqueous Layer and Confirmation of Formation of Thiourea Compound (4)) It was confirmed by HPLC that the aqueous layer contained thiourea as the thiourea compound (4).

[0145] Table 2 shows whether or not a thiourea compound (4) (thiourea in this example) was produced by the reaction of the isothiuronium salt (1-2). Specifically, when the content of thiourea in the aqueous layer was greater than the content of unreacted thiourea in the aqueous solution of isothiuronium salt (1-2) obtained in Production Example 2, the production of thiourea compound (4) was judged to be "present," and when there was no increase, the production of thiourea compound (4) was judged to be "absent."

[0146] (Treatment and Analysis of Organic Layer, and Confirmation of Production of Thiol Compound (5)) The organic layer was subjected to acid washing twice with 125 parts by mass of 35% by mass aqueous hydrochloric acid at 35°C to 43°C for 30 minutes, and then washed five times with 125 parts by mass of degassed water (dissolved oxygen concentration 2 ppm) at 35°C to 45°C for 15 minutes. From the organic layer after the above washing, the solvent was distilled off under heating and reduced pressure, and then trace amounts of water were removed under heating and reduced pressure, followed by filtration under reduced pressure using a 3 μm PTFE-type membrane filter to obtain a polythiol composition containing thiol compound (5-2) as a main component as thiol compound (5). Here, the thiol compound (5-2) is the aforementioned polythiol component A2 (i.e., at least one selected from the group consisting of 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane).

[0147] Table 2 shows whether or not a thiol compound (5) (thiol compound (5-2) in this example) was produced by the reaction of the isothiuronium salt (1-2). The production of the thiol compound (5) was confirmed by HPLC.

[0148]

[0149] As shown in Table 2, in Example 101, in which isothiuronium salt (1) was reacted in the presence of sulfur-containing compound (2) and at least one selected from the group consisting of basic compound (3) and ammonia, thiourea compound (4) and thiol compound (5) were produced, and gas generation was suppressed.

[0150] The disclosure of Japanese Patent Application No. 2023-212546, filed on December 15, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for producing a thiol compound, comprising a reaction step of reacting an isothiuronium salt (1) represented by the following formula (1) in the presence of a sulfur-containing compound (2) represented by the following formula (2), a basic compound (3) represented by the following formula (3), and at least one selected from the group consisting of ammonia, to obtain a thiourea compound (4) represented by the following formula (4) and a thiol compound (5) represented by the following formula (5). [In the formula (1), the formula (4), and the formula (5), R １ represents an n1-valent organic group having 1 to 30 carbon atoms, n1 represents an integer of 1 to 8, R ２ , R ３ , and R ４ each independently represents a hydrogen atom or a monovalent organic group having 1 to 10 carbon atoms, and X represents a halogen atom. １ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ In formula (3), m represents an integer of 1 to 3, n represents an integer of 1 to 3, and k represents an integer of 0 to 3. ２ is an alkali metal atom, an alkaline earth metal atom, or NH ４ ＋ where p is an integer of 1 to 2, and q is an integer of 1 to 2.

2. R in the formula (1) and the formula (5) １ The method for producing a thiol compound according to claim 1, wherein is a group having the following structure (RS1): [In the structure (RS1), the eight *s each represent a binding position.] 3. R ​​in the formula (1) and the formula (5) １ is a residue in which at least one mercapto group has been removed from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, a residue in which at least one mercapto group has been removed from 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue in which at least one mercapto group has been removed from 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue in which at least one mercapto group has been removed from 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, a residue in which at least one mercapto group has been removed from 2,5-bismercaptomethyl-1,4-dithiane, or a residue in which at least one mercapto group has been removed from bis(2-mercaptoethyl)sulfide.

4. The method for producing a thiol compound according to claim 1, wherein the reaction step is carried out at a pH of 7 or higher.

5. The method for producing a thiol compound according to claim 1, wherein the reaction step is carried out under conditions of 30°C to 80°C.

6. The method for producing a thiol compound according to claim 1, wherein the reaction step is carried out in the presence of the sulfur-containing compound (2), at least one selected from the group consisting of the basic compound (3) and ammonia, and at least one selected from the group consisting of an alkali metal sulfite and an alkaline earth metal sulfite.

7. A method for producing a thiol compound according to claim 1, comprising, prior to the reaction step, a step of reacting the thiourea compound (4) with a compound (Px) represented by the following formula (Px) to produce the isothiuronium salt (1). [In formula (Px), R Ｘ represents an n1-valent organic group having 1 to 30 carbon atoms, n1 represents an integer of 1 to 8, and A represents a hydroxy group or a halogen atom. A present in formula (Px) may be the same or different.

8. A method for producing a raw material for optical materials containing a thiol compound, comprising a step of producing the thiol compound (5) by the method for producing a thiol compound according to any one of claims 1 to 7.

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