Method for producing thioester compounds, and thioester compounds

Abstract

To provide a method for producing a thioester compound. The raw material component contains (A) a carboxylic acid, (B) a halide of toluenesulfonic acid, (C) a first tertiary amine compound, (D) a second tertiary amine compound, and (E) thiol. The reaction includes a first reaction for reacting (A) and (B) in the presence of (C) to obtain a first intermediate product, a second reaction for reacting the first intermediate product with (D) to obtain a second intermediate product, and a third reaction for reacting the second intermediate product with (E) to obtain a thioester compound. The acid dissociation constant of a conjugate acid (C) is 7.8 or more. (D) contains a cyclic-structure-containing amine having two or more tertiary amino groups per molecule. The amount of (C) is from 1 equivalent to less than 2 equivalents, the amount of (D) is from 1 equivalent to less than 2 equivalents, and the total amount of (C) and (D) is less than 3 equivalents, all relative to the carboxy groups of (A).

Description

Technical Field

[0001] The present invention relates to a method for producing a thioester compound and a thioester compound.

Background Art

[0002] A thioester compound is a compound having a thioester bond (-S-C(=O)-). As a method for producing a thioester compound, the following method is known.

[0003] More specifically, in this method, first, a carboxylic acid (R 1 CO2H), p-toluenesulfonyl chloride (TsCl), and N-methylimidazole (NMIMZ) are sequentially reacted. Thereby, an adduct in which N-methylimidazole is added to the carboxylic acid is obtained. Next, the above adduct and a thiol (R 2 SH) are reacted. Thereby, a thiol is added to the carboxylic acid, and a thioester bond (-S-C(=O)-) is formed. In this reaction, the amount of p-toluenesulfonyl chloride is 1.2 equivalents with respect to the carboxy group of the carboxylic acid. The amount of N-methylimidazole is 3.0 equivalents with respect to the carboxy group of the carboxylic acid. The amount of thiol is 1.0 equivalent with respect to the carboxy group of the carboxylic acid (see, for example, Non-Patent Document 1 (Scheme 1)).

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

[0005] However, the above method uses a relatively large amount (3.0 equivalents) of N-methylimidazole. Therefore, the above method is costly. In addition, the thioester compound obtained by the above method contains a relatively large amount (3.0 equivalents) of N-methylimidazole. Therefore, there is a problem in that the thioester compound turns yellow.

[0006] On the other hand, reducing the amount of N-methylimidazole used in the above method is being considered. However, reducing the amount of N-methylimidazole used reduces the reaction efficiency. In other words, the addition efficiency between the carboxylic acid and the thiol decreases. As a result, the yield of the product in which all mercapto groups of the thiol are thioesterified (total adduct) decreases.

[0007] The present invention relates to a method for producing thioester compounds that can be manufactured at a relatively low cost and with a relatively high yield, and to a thioester compound with relatively low yellowness. [Means for solving the problem]

[0008] The present invention [1] is a method for producing a thioester compound, comprising a reaction step of producing the thioester compound by a reaction of raw material components, wherein the raw material components include (A) a carboxylic acid, (B) a halogen of toluenesulfonic acid, (C) a first tertiary amine compound, (D) a second tertiary amine compound, and (E) a thiol, wherein the reaction in the reaction step comprises a first reaction in which (A) a carboxylic acid and (B) a halogen of toluenesulfonic acid are reacted in the presence of (C) a first tertiary amine compound to obtain a first intermediate product, a second reaction in which the first intermediate product is reacted with (D) a second tertiary amine compound to obtain a second intermediate product, and the second intermediate product The present invention provides a method for producing a thioester compound, comprising a third reaction in which (E) a thiol is reacted to obtain a thioester compound, wherein the acid dissociation constant (pKa1) of the conjugate acid of the (C) first tertiary amine compound is 7.8 or greater, the (D) second tertiary amine compound contains a ring structure-containing amine having two or more tertiary amino groups in one molecule, the amount of the (C) first tertiary amine compound is 1.0 equivalent or more and less than 2.0 equivalents relative to the carboxyl group of the (A) carboxylic acid, the amount of the (D) second tertiary amine compound is 1.0 equivalent or more and less than 2.0 equivalents, and the total amount of the (C) first tertiary amine compound and the (D) second tertiary amine compound is less than 3.0 equivalents.

[0009] The present invention [2] includes a method for producing a thioester compound as described in [1] above, wherein in the reaction step, the raw material components are first supplied sequentially or simultaneously to the first reaction and the second reaction, and after the completion of the first reaction and the second reaction, to the third reaction.

[0010] The present invention [3] includes a method for producing a thioester compound as described in [2] above, wherein in the reaction step, the raw material component is subjected to the first reaction before the start of the second reaction and before the start of the third reaction, subjected to the second reaction after the completion of the first reaction and before the start of the third reaction, and subjected to the third reaction after the completion of the first reaction and after the completion of the second reaction.

[0011] The present invention [4] includes a method for producing a thioester compound according to any one of the above [1] to [3], wherein the acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound (C) is greater than the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound (D).

[0012] The present invention [5] includes a method for producing a thioester compound according to any one of the above [1] to [4], wherein the (C) first tertiary amine compound includes a ring-structure-free amine.

[0013] The present invention [6] includes a method for producing a thioester compound according to any one of the above [1] to [5], wherein the (D) second tertiary amine compound contains at least one selected from the group consisting of N-methylimidazole, 4-dimethylaminopyridine, and diazabicyclononene.

[0014] The present invention [7] includes a method for producing a thioester compound according to any one of the above [1] to [6], wherein the (E) thiol contains an aliphatic thiol.

[0015] The present invention [8] includes a method for producing a thioester compound according to any one of the above [1] to [7], wherein the (E) thiol has a sulfide bond.

[0016] The present invention [9] includes a method for producing a thioester compound according to any one of the above [1] to [8], wherein the (E) thiol contains at least one selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane.

[0017] The present invention

[10] includes a method for producing a thioester compound according to any one of the above [1] to [9], wherein the thioester compound is represented by the following general formula (1).

[0018] [Chemical formula]

[0019] <映画 (In formula (1), A represents an n-valent organic group containing a sulfur atom. n represents an integer of 1 or more. S represents a sulfur atom. X represents a carbonyl group (-C(=O)-). R represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an araliphatic hydrocarbon group. R may have a substituent. R may be the same or different from each other.)

[0020] The present invention

[11] includes a method for producing the thioester compound according to

[10] above, wherein in the above formula (1), the molecular weight of A is 50 or more and 9000 or less.

[0021] The present invention

[12] includes a method for producing the thioester compound according to

[10] or

[11] above, wherein the thioester compound is represented by the following general formula (2) or the following general formula (3).

[0022] [Chemical formula] ​​​​​​​​​​​​​​​​​The present invention

[13] contains a thioester compound having a content of 1 ppm to 1000 ppm of a ring structure-containing amine having two or more tertiary amino groups in one molecule, and a yellow index of 7.0 or less. [Effects of the Invention]

[0026] The present invention provides a method for producing thioester compounds that are relatively low in yellowness and at a relatively low cost. Furthermore, this method allows for the production of thioester compounds in which all mercapto groups of the thiol are thioesterified (total adducts) in relatively high yield.

[0027] Furthermore, the thioester compounds of the present invention can be manufactured at a relatively low cost and have relatively low yellowness. In addition, these thioester compounds contain a relatively high proportion of thioester compounds (total adducts) in which all mercapto groups of the thiol are thioesterified. [Modes for carrying out the invention]

[0028] 1. Method for producing thioester compounds (1) Raw material components Thioester compounds are compounds that have a thioester bond (-SC(=O)-). Thioester compounds are produced when certain starting components are subjected to the reaction described below.

[0029] The raw material components include (A) a carboxylic acid, (B) a halogen of toluenesulfonic acid, (C) a first tertiary amine compound, (D) a second tertiary amine compound, and (E) a thiol. Each component is described in detail below.

[0030] [Carboxylic acid] (A) Examples of carboxylic acids include monocarboxylic acids, polycarboxylic acids, and acid anhydrides, with monocarboxylic acids being preferred. Examples of monocarboxylic acids include aliphatic monocarboxylic acids, aromatic monocarboxylic acids, and aromatic aliphatic monocarboxylic acids. Examples of aliphatic monocarboxylic acids include linear aliphatic monocarboxylic acids and alicyclic monocarboxylic acids, more specifically, acetic acid, propionic acid, butyric acid, caproic acid, octic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 2-ethylhexanoic acid, cyclohexanecarboxylic acid, and cyclopentanecarboxylic acid. Examples of aromatic monocarboxylic acids include benzoic acid and toluic acid. Examples of aromatic aliphatic monocarboxylic acids include phenylacetic acid, 3-phenylpropionic acid, and diphenylacetic acid. These are used alone or in combination of two or more. Preferably, aromatic aliphatic monocarboxylic acids are used, and more preferably, 3-phenylpropionic acid is used.

[0031] [Halogenated toluenesulfonic acid] (B) Halides of toluenesulfonic acid are obtained by halogenating toluenesulfonic acid by known methods. Examples of toluenesulfonic acid include p-toluenesulfonic acid, m-toluenesulfonic acid, and o-toluenesulfonic acid. These can be used individually or in combination of two or more. Preferably, p-toluenesulfonic acid is used as the toluenesulfonic acid. Examples of halogens include fluorine, chlorine, bromine, and iodine. These can be used individually or in combination of two or more. Preferably, chlorine is used as the halogen.

[0032] (B) More specifically, examples of halogenated toluenesulfonic acid include p-toluenesulfonic acid fluoride, p-toluenesulfonic acid chloride, m-toluenesulfonic acid fluoride, and m-toluenesulfonic acid chloride. These can be used individually or in combination of two or more. Preferably, p-toluenesulfonic acid chloride is used as the halogenated toluenesulfonic acid.

[0033] [Tertiary amine compounds] A tertiary amine compound is an organic compound having one or more tertiary amino groups in one molecule. The raw material components, as described above, contain (C) a first tertiary amine compound and (D) a second tertiary amine compound.

[0034] [First tertiary amine compound] (C) The first tertiary amine compound is a tertiary amine compound having a conjugate acid dissociation constant (pKa1) greater than or equal to a predetermined value.

[0035] More specifically, the acid dissociation constant (pKa1) of the conjugate acid of the (C) first tertiary amine compound is 7.8 or higher, preferably 8.0 or higher, more preferably 9.0 or higher, even more preferably 10.0 or higher, and particularly preferably 10.5 or higher. Also, the acid dissociation constant (pKa1) of the conjugate acid of the (C) first tertiary amine compound is, for example, 13.0 or lower, preferably 12.0 or lower, more preferably 11.5 or lower, and even more preferably 11.0 or lower.

[0036] Furthermore, the acid dissociation constant of the conjugate acid of the first tertiary amine compound (C) can be determined by neutralization titration. In addition, when two or more tertiary amine compounds are used in combination, the acid dissociation constant of the conjugate acid of the first tertiary amine compound (C) is the average value of the acid dissociation constants of the conjugate acids of each tertiary amine compound.

[0037] (C) The first tertiary amine compound only needs to have an acid dissociation constant (pKa1) of the conjugate acid that is greater than or equal to a predetermined value, and the molecular structure of (C) the first tertiary amine compound is not particularly limited.

[0038] For example, in (C) the first tertiary amine compound, the number of tertiary amino groups is not particularly limited and may be singular (one) or plural (two or more). Furthermore, (C) the first tertiary amine compound may or may not have a ring structure. Examples of ring structures include aromatic rings, alicyclic rings, and heterocyclic rings.

[0039] (C) More specifically, the first tertiary amine compound includes, for example, triethylamine (TEA, conjugate acid pKa 10.7), N-ethyldiisopropylamine (DIPEA, conjugate acid pKa 11.4), triethylenediamine (TEDA, conjugate acid pKa 8.7), N-methylmorpholine (NMM, conjugate acid pKa 7.8), 4-dimethylaminopyridine (DMAP, conjugate acid pKa 9.9), and diazabicyclononene (DBN, conjugate acid pKa 13.5). These can be used alone or in combination of two or more.

[0040] From the viewpoint of resistance to yellowing, (C) the first tertiary amine compound is preferably a tertiary amine that does not contain an aromatic ring structure in its molecule (an aromatic ring-free amine). That is, (C) the first tertiary amine compound preferably includes an aromatic ring-free amine. (C) the first tertiary amine compound is more preferably an aromatic ring-free amine.

[0041] Among the (C) first tertiary amine compounds described above, examples of amines that do not contain an aromatic ring structure include triethylamine (TEA, conjugate acid pKa 10.7), N-ethyldiisopropylamine (DIPEA, conjugate acid pKa 11.4), triethylenediamine (TEDA, conjugate acid pKa 8.7), and N-methylmorpholine (NMM, conjugate acid pKa 7.8). These can be used alone or in combination of two or more.

[0042] From the viewpoint of resistance to yellowing, (C) the first tertiary amine compound is more preferably a tertiary amine that does not contain a ring structure (aromatic ring, alicyclic ring, or heterocyclic ring) in its molecule (a ring structure-free amine). That is, (C) the first tertiary amine compound is more preferably a ring structure-free amine. (C) The first tertiary amine compound is particularly preferably a ring structure-free amine.

[0043] Among the first tertiary amine compounds (C) described above, examples of amines that do not contain a ring structure include triethylamine (TEA, conjugate acid pKa 10.7) and N-ethyldiisopropylamine (DIPEA, conjugate acid pKa 11.4). These can be used alone or in combination of two or more.

[0044] Furthermore, (C) the first tertiary amine compound preferably includes a tertiary amine having one tertiary amino group in one molecule. That is, (C) the first tertiary amine compound preferably includes a tertiary monoamine. (C) the first tertiary amine compound preferably consists of a tertiary monoamine.

[0045] Among the tertiary amine compounds of (C) above, examples of tertiary monoamines include triethylamine (TEA, conjugate acid pKa 10.7), N-ethyldiisopropylamine (DIPEA, conjugate acid pKa 11.4), and N-methylmorpholine (NMM, conjugate acid pKa 7.8). These can be used alone or in combination of two or more.

[0046] From the viewpoint of low cost, triethylamine (TEA, pKa of the conjugate acid 10.7) is particularly preferred as the first tertiary amine compound.

[0047] [Second tertiary amine compound] (D) The second tertiary amine compound is a tertiary amine compound having a predetermined molecular structure.

[0048] More specifically, (D) the second tertiary amine compound has two or more tertiary amino groups in one molecule and one or more ring structures in one molecule. Hereinafter, such amine compounds may be referred to as "ring structure-containing, polyfunctional, tertiary amines."

[0049] (D) The second tertiary amine compound contains a ring-structure-containing amine having two or more tertiary amino groups in one molecule. (D) The second tertiary amine compound preferably consists of a ring-structure-containing amine having two or more tertiary amino groups in one molecule.

[0050] (D) The second tertiary amine compound only needs to have the above molecular structure, and the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound (D) is not particularly limited.

[0051] For example, (D) the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound may be smaller than (C) the acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound, or it may be larger than (C) the acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound, or it may be the same as (C) the acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound.

[0052] (D) The acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound is, for example, 5.0 or higher, preferably 6.0 or higher, and more preferably 7.0 or higher. Also, (D) the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound is, for example, 13.0 or lower, preferably 11.0 or lower, more preferably 9.0 or lower, even more preferably less than 7.8, and particularly preferably 7.5 or lower.

[0053] Furthermore, the acid dissociation constant of the conjugate acid of the second tertiary amine compound (D) can be determined by neutralization titration. In addition, when two or more tertiary amine compounds are used in combination, the acid dissociation constant of the conjugate acid of the second tertiary amine compound (D) is the average value of the acid dissociation constants of the conjugate acids of each tertiary amine compound.

[0054] (D) More specifically, examples of the second tertiary amine compound include N-methylimidazole (NMIMZ, conjugate acid pKa 7.1), 4-dimethylaminopyridine (DMAP, conjugate acid pKa 9.9), and diazabicyclononene (DBN, conjugate acid pKa 13.5). These can be used alone or in combination of two or more.

[0055] From the viewpoint of reaction efficiency, (D) the second tertiary amine compound is preferably a compound having a resonance structure, more specifically, N-methylimidazole (NMIMZ, conjugate acid pKa 7.1), 4-dimethylaminopyridine (DMAP, conjugate acid pKa 9.9), and diazabicyclononene (DBN, conjugate acid pKa 13.5). In other words, (D) the second tertiary amine compound preferably contains at least one selected from the group consisting of N-methylimidazole, 4-dimethylaminopyridine, and diazabicyclononene. (D) the second tertiary amine compound is more preferably consisting of at least one selected from the group consisting of N-methylimidazole, 4-dimethylaminopyridine, and diazabicyclononene. From the viewpoint of low cost, N-methylimidazole (NMIMZ, conjugate acid pKa 7.1) is particularly preferred as the second tertiary amine compound.

[0056] Furthermore, the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound (D) is not particularly limited, but preferably, the acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound (C) is greater than the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound (D).

[0057] In other words, the combination of the first tertiary amine compound (C) and the second tertiary amine compound (D) is selected such that the acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound (C) is greater than the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound (D). If the acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound (C) is greater than the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound (D), the hydrochloric acid produced as a by-product when the first intermediate product (described later) is formed, and the first tertiary amine compound (C), produce a more stable amine hydrochloride. Therefore, the formation of the first intermediate product (described later) can be promoted. As a result, the thioester compound can be obtained in a higher yield.

[0058] For example, if (C) triethylamine (TEA, pKa of conjugate acid 10.7) is selected as the first tertiary amine compound, then (D) the second tertiary amine compound is preferably N-methylimidazole (NMIMZ, pKa of conjugate acid 7.1) and 4-dimethylaminopyridine (DMAP, pKa of conjugate acid 9.9).

[0059] Furthermore, for example, if (D) N-methylimidazole (NMIMZ, pKa of conjugate acid 7.1) is selected as the second tertiary amine compound, then (C) the first tertiary amine compound can preferably be triethylamine (TEA, pKa of conjugate acid 10.7), N-ethyldiisopropylamine (DIPEA, pKa of conjugate acid 11.4), triethylenediamine (TEDA, pKa of conjugate acid 8.7), and N-methylmorpholine (NMM, pKa of conjugate acid 7.8).

[0060] In such cases, from the viewpoint of reaction efficiency, the difference between the acid dissociation constant (pKa1) of the conjugate acid of (C) the first tertiary amine compound and the acid dissociation constant (pKa2) of the conjugate acid of (D) the second tertiary amine compound is, for example, 0 or more, preferably 1.0 or more, and more preferably 3.0 or more. Furthermore, from the viewpoint of suppressing side reactions, the difference between the acid dissociation constant (pKa1) of the conjugate acid of (C) the first tertiary amine compound and the acid dissociation constant (pKa2) of the conjugate acid of (D) the second tertiary amine compound is, for example, 5.0 or less, preferably 4.0 or less.

[0061] Furthermore, (C) the first tertiary amine compound and (D) the second tertiary amine compound may be the same type of tertiary amine compound, or they may be different types of tertiary amine compounds.

[0062] In other words, if a tertiary amine compound has an acid dissociation constant (pKa) of a conjugate acid greater than or equal to the predetermined value mentioned above, and does not have the predetermined structure (ring structure-containing, polyfunctional, tertiary amine), then the tertiary amine compound can be used as (C) a first tertiary amine compound, and (D) cannot be used as a second tertiary amine compound.

[0063] Furthermore, if a tertiary amine compound does not have a conjugate acid dissociation constant (pKa) greater than or equal to the predetermined value mentioned above, and has the predetermined structure (ring structure-containing, polyfunctional, tertiary amine), then the tertiary amine compound is (C) unusable as a first tertiary amine compound and (D) usable as a second tertiary amine compound.

[0064] When such tertiary amine compounds are used, (C) the first tertiary amine compound and (D) the second tertiary amine compound are different types of tertiary amine compounds.

[0065] On the other hand, if a tertiary amine compound has a conjugate acid dissociation constant (pKa) greater than or equal to the predetermined value, and has the predetermined structure (ring structure-containing, polyfunctional, tertiary amine), then the tertiary amine compound can be used as (C) a first tertiary amine compound and (D) a second tertiary amine compound.

[0066] When such tertiary amine compounds are used, (C) the first tertiary amine compound and (D) the second tertiary amine compound may be the same type of tertiary amine compound.

[0067] From the viewpoint of low cost and reaction efficiency, preferably, (C) the first tertiary amine compound and (D) the second tertiary amine compound are different types of tertiary amine compounds.

[0068] [Thiol] (E) Examples of thiols include aliphatic thiols, aromatic thiols, and aromatic aliphatic thiols. From the viewpoint of resistance to yellowing, aliphatic thiols are preferred. Examples of aliphatic thiols include linear aliphatic thiols and alicyclic thiols. In particular, when the thioester compound is used as a plasticizer (described later) for the resin molded product, linear aliphatic thiols are preferred from the viewpoint of flexibility of the resin molded product.

[0069] Furthermore, examples of (E) thiols include thiols having a sulfide bond (-S-) in the molecule and thiols not having a sulfide bond (-S-) in the molecule. Thiols having a sulfide bond (-S-) in the molecule are, for example, thiols that contain a sulfur atom in addition to the mercapto group. Thiols not having a sulfide bond (-S-) in the molecule are, for example, thiols that do not contain a sulfur atom in addition to the mercapto group.

[0070] In particular, when a thioester compound is used as a refractive index modifier (described later) for a resin molded product, from the viewpoint of improving the refractive index of the resin molded product, thiols having a sulfide bond (-S-) in the molecule are preferred, and aliphatic thiols having a sulfide bond (-S-) in the molecule are particularly preferred.

[0071] Examples of aliphatic thiols having a sulfide bond (-S-) in their molecule include sulfide-containing aliphatic monothiols, sulfide-containing aliphatic dithiols, sulfide-containing aliphatic trithiols, sulfide-containing aliphatic tetrathiols, sulfide-containing aliphatic pentathiols, sulfide-containing aliphatic hexathiols, and sulfide-containing aliphatic octatiols.

[0072] Sulfide-containing aliphatic monothiols are monofunctional thiols that contain a sulfur atom in addition to the mercapto group. An example of a sulfide-containing aliphatic monothiol is 2-(ethylthio)ethanethiol.

[0073] Sulfide-containing aliphatic dithiols are difunctional thiols that contain a sulfur atom in addition to the mercapto group. Examples of sulfide-containing aliphatic dithiols include bis(mercaptomethyl)sulfide, bis(2-mercaptoethyl)sulfide, bis(3-mercaptopropyl)sulfide, and bis(4-mercaptobutyl)sulfide.

[0074] Sulfide-containing aliphatic trithiols are trifunctional thiols that contain a sulfur atom in addition to the mercapto group. Examples of sulfide-containing aliphatic trithiols include 1,2,3-tris(mercaptomethylthio)propane, 1,2,3-tris(2-mercaptoethylthio)propane, 1,2,3-tris(3-mercaptopropylthio)propane, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST), 2,2-bis(mercaptomethylthio)ethanethiol, 3-mercaptomethylthio-1,7-dimercapto-2,6-dithiaheptane, 3-mercaptomethylthio-1,6-dimercapto-2,5-dithiahexane, and 4,6-bis[4-(6-mercaptomethylthio)-1,3-dithiaani Examples include trithio-6-[4-(6-mercaptomethylthio)-1,3-dithianylthio]-1,3-dithiane, tris(mercaptomethylthio)methane, tris(mercaptoethylthio)methane, 2,4,6-tris(mercaptomethylthio)-1,3,5-trithiacyclohexane, tris[(4-mercaptomethyl-2,5-dithiacyclohexyl-1-yl)methylthio]methane, 4-mercaptomethyl-2-(2,3-dimercaptopropylthio)-1,3-dithiacyclopentane, and 4-mercaptomethyl-2-(1,3-dimercapto-2-propylthio)-1,3-dithiacyclopentane.

[0075] Sulfide-containing aliphatic tetrathiols are tetrafunctional thiols that contain a sulfur atom in addition to the mercapto group. Examples of sulfide-containing aliphatic tetrathiols include 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (FSH), 4,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, 4,8-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, tetrakis(mercaptomethylthiomethyl)methane, tetrakis(2-mercaptoethylthiomethyl)methane, tetrakis(3-mercaptopropylthiomethyl)methane, and (2,3-dimercaptopropyl) sulfide, bis(2,3-dimercaptopropyl ester) thiodipropionate, bis(2,3-dimercaptopropyl ester) dithiodiglycolate, bis(2,3-dimercaptopropyl ester) thiodipropionate, bis(2,3-dimercaptopropyl ester) dithiodipropionate, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 1,1,2,2-tetrakis(mercaptomethylthio)ethane, 1,1,5,5-tetrakis(mercaptomethylthio O)-3-thiapentane, 1,1,6,6-tetrakis(mercaptomethylthio)-3,4-dithiahexane, 2,5-bis(4,4-bis(mercaptomethylthio)-2-thiabutyl)-1,4-dithiane, 2,2-bis(mercaptomethylthio)-1,3-propanedithiol, 3,6-bis(mercaptomethylthio)-1,9-dimercapto-2,5,8-trithianonane, 4-[3,5-bis(mercaptomethylthio)-7-mercapto-2,6-dithiaheptylthio]-6-mercaptomethylthio-1,3-dithia Ahn, 1,1-bis[4-(6-mercaptomethylthio)-1,3-dithianylthio]-1,3-bis(mercaptomethylthio)propane, 3-[2-(1,3-dithiethanyl)]methyl-7,9-bis(mercaptomethylthio)-1,11-dimercapto-2,4,6,10-tetrathiaundecane, 4-[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]-5-mercaptomethylthio-1,3-dithiolane, 2-[3,4-bis(mercaptomethylthio)-6-mercapto-2,Examples include 5-dithiahexylthio]mercaptomethylthiomethyl-1,3-dithiethane, 4-{1-[2-(1,3-dithietanyl)]-3-mercapto-2-thiapropylthio}-5-[1,2-bis(mercaptomethylthio)-4-mercapto-3-thiabutylthio]-1,3-dithiolane, 1,1,5,5-tetrakis(mercaptomethylthio)-2,4-dithiapentane, and 1,1,3,3-tetrakis(mercaptomethylthio)-2-thiapropane.

[0076] Sulfide-containing aliphatic pentatiols are pentafunctional thiols that contain a sulfur atom in addition to the mercapto group. Examples of sulfide-containing aliphatic pentatiols include 1-[4-(6-mercaptomethylthio)-1,3-dithianylthio]-3-[2,2-bis(mercaptomethylthio)ethyl]-7,9-bis(mercaptomethylthio)-2,4,6,10-tetrathiaundecane and bis[4,4-bis(mercaptomethylthio)-1,3-dithiabutyl]-(mercaptomethylthio)methane.

[0077] Sulfide-containing aliphatic hexathiols are hexafunctional thiols that contain a sulfur atom in addition to the mercapto group. Examples of sulfide-containing aliphatic hexathiols include 1,1,9,9-tetrakis(mercaptomethylthio)-5-(3,3-bis(mercaptomethylthio)-1-thiapropyl)3,7-dithianonane, tris(2,2-bis(mercaptomethylthio)ethyl)methane, tris(4,4-bis(mercaptomethylthio)-2-thiabutyl)methane, 3,5,9,11-tetrakis(mercaptomethylthio)-1,13-dimercapto-2,6,8,12-tetrathiatridecane, and 3,4,8,9-tetrakis( Lucaptomethylthio)-1,11-dimercapto-2,5,7,10-tetrathiaundecane, 4,6-bis[3,5-bis(mercaptomethylthio)-7-mercapto-2,6-dithiaheptylthio]-1,3-dithiane, 3-[2-(1,3-dithiethanyl)]methyl-7,9,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-2,4,6,10,12,16-hexathiaheptadecane, 4-[3,4,8,9-tetrakis(mercaptomethylthio)-11-mercapto-2,5,7 ,10-tetrathiaundecyl]-5-mercaptomethylthio-1,3-dithiolane, 4,5-bis[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio]-1,3-dithiolane, 4-[3-bis(mercaptomethylthio)methyl-5,6-bis(mercaptomethylthio)-8-mercapto-2,4,7-trithiaoctyl]-5-mercaptomethylthio-1,3-dithiolane, 2-{bis[3,4-bis(mercaptomethylthio)-6-mercapto-2,5-dithiahexylthio ]methyl}-1,3-dithiethane, 2-[3,4,8,9-tetrakis(mercaptomethylthio)-11-mercapto-2,5,7,10-tetrathiaundecylthio]mercaptomethylthiomethyl-1,3-dithiethane, 2-[3-bis(mercaptomethylthio)methyl-5,6-bis(mercaptomethylthio)-8-mercapto-2,4,7-trithiaoctyl]mercaptomethylthiomethyl-1,3-dithiethane, tris[4,4-bis(mercaptomethylthio)-1,3-dithiabutyl]methane, tris[2,Examples include 2-bis(mercaptomethylthio)-2-thiapropyl]methane, tris[4,4-bis(mercaptomethylthio)-3-thiabutyl]methane, and 2,4,6-tris[3,3-bis(mercaptomethylthio)-2-thiapropyl]-1,3,5-trithiacyclohexane.

[0078] Sulfide-containing aliphatic octatiols are octafunctional thiols that contain a sulfur atom in addition to the mercapto group. Examples of sulfide-containing aliphatic octatiols include tetrakis(4,4-bis(mercaptomethylthio)-2-thiabutyl)methane, 3,5,9,11,15,17-hexakis(mercaptomethylthio)-1,19-dimercapto-2,6,8,12,14,18-hexathianonadecane, 9-(2,2-bis(mercaptomethylthio)ethyl)-3,5,13,15-tetrakis(mercaptomethylthio)-1,17-dimercapto-2,6,8,10,12,16-hexathiaheptadecane, tetrakis( Examples include 2,2-bis(mercaptomethylthio)ethyl)methane, 3,4,8,9,13,14-hexakis(mercaptomethylthio)-1,16-dimercapto-2,5,7,10,12,15-hexatiahexadecane, 8-[bis(mercaptomethylthio)methyl]-3,4,12,13-tetrakis(mercaptomethylthio)-1,15-dimercapto-2,5,7,9,11,14-hexatiapentadecane, and tetrakis[3,3-bis(mercaptomethylthio)-2-thiapropyl]methane.

[0079] Furthermore, (E) thiols can also include, for example, high molecular weight polythiols. High molecular weight polythiols are polythiols with relatively high molecular weight. Relatively high molecular weight means a molecular weight of 400 or more. The molecular weight of a high molecular weight polythiol is calculated from its molecular skeleton and the number of atoms. When multiple high molecular weight polythiols are used in combination, the high molecular weight polythiol is calculated as the average value of the molecular weights of each high molecular weight polythiol (the same applies below). Also, if the high molecular weight polythiol is a polymer, its molecular weight can also be measured as the polystyrene-equivalent molecular weight by gel permeation chromatography (GPC) (the same applies below). High molecular weight polythiols can be obtained, for example, by bonding multiple (two or more) low molecular weight polythiols together.

[0080] Low molecular weight polythiols are polythiols with a relatively low molecular weight. Relatively low molecular weight means a molecular weight of less than 400. The molecular weight of a low molecular weight polythiol is calculated from its molecular skeleton and the number of atoms. When multiple low molecular weight polythiols are used in combination, the molecular weight of the polythiol is calculated as the average of the molecular weights of each individual polythiol (the same applies hereafter). Furthermore, if the low molecular weight polythiol is a polymer, its molecular weight can be measured as the polystyrene-equivalent molecular weight using gel permeation chromatography (GPC) (the same applies hereafter). Examples of low molecular weight polythiols include known sulfur-containing dithiols, known sulfur-containing trithiols, sulfur-containing tetrathiols, known sulfur-containing pentatiols, known sulfur-containing hexatiols, and known sulfur-containing octatiols. The method of bonding multiple (two or more) low molecular weight polythiols to each other is not particularly limited and can be appropriately selected according to the purpose and application.

[0081] These can be used alone or in combination of two or more. From the viewpoint of improving refractive index, preferably, sulfide-containing aliphatic trithiols and sulfide-containing aliphatic tetrathiols are mentioned, and more preferably, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST) and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (FSH) are mentioned. In other words, preferably, (E) thiol contains at least one selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST) and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (FSH). More preferably, the (E) thiol consists of at least one selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST) and 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (FSH).

[0082] (2) Reaction process In the production of thioester compounds, the above raw material components are reacted to produce the thioester compound (reaction step).

[0083] The reaction in the reaction step includes a first reaction, a second reaction, and a third reaction. The first, second, and third reactions may be carried out sequentially or simultaneously.

[0084] The following details the configuration in which the first, second, and third reactions are carried out sequentially.

[0085] [First reaction] The first reaction involves reacting (A) a carboxylic acid with (B) a halogen of toluenesulfonic acid in the presence of (C) a first tertiary amine compound to obtain the first intermediate product.

[0086] More specifically, in the first reaction, for example, (A) carboxylic acid is first dissolved in a solvent to prepare a solution of (A) carboxylic acid. The solvent is not particularly limited, and known organic solvents (e.g., acetonitrile, dichloromethane, and toluene) can be used. The proportion of the solvents is not particularly limited and can be set as appropriate depending on the purpose and application.

[0087] Next, in the first reaction, a solution of (A) carboxylic acid and (C) the first tertiary amine compound are mixed. The mixing ratio of the solution of (A) carboxylic acid to (C) the first tertiary amine compound is adjusted based on the equivalent ratio of the first tertiary amine compound to the carboxyl group of (A) carboxylic acid (first tertiary amine compound / carboxyl group).

[0088] More specifically, from the viewpoint of reaction efficiency, the amount of (C) the first tertiary amine compound relative to the carboxyl group of (A) the carboxylic acid is 1.0 equivalent or more, preferably 1.05 equivalents or more, and more preferably 1.1 equivalents or more. Also, from the viewpoint of low cost, the amount of (C) the first tertiary amine compound relative to the carboxyl group of (A) the carboxylic acid is less than 2.0 equivalents, preferably 1.5 equivalents or less, and more preferably 1.3 equivalents or less.

[0089] The above mixing process allows (A) a solution of carboxylic acid and (C) the first tertiary amine compound to coexist in an unreacted state. The mixing conditions are not particularly limited. For example, the mixing temperature may be, for example, -50°C or higher. Alternatively, the mixing temperature may be, for example, 20°C or lower, preferably 10°C or lower, and more preferably 5°C or lower.

[0090] The above mixing yields a mixture containing (A) a solution of carboxylic acid and (C) a first tertiary amine compound.

[0091] Next, in the first reaction, the above mixture is mixed with the halogen of (B) toluenesulfonic acid. The mixing ratio of the above mixture to the halogen of (B) toluenesulfonic acid is adjusted based on the equivalent ratio of the halogen of (B) toluenesulfonic acid to the carboxyl group of (A) carboxylic acid (first tertiary amine compound / carboxyl group).

[0092] More specifically, from the viewpoint of reaction efficiency, the amount of halogenated toluenesulfonic acid (B) relative to the carboxyl groups of carboxylic acid (A) is 1.0 equivalent or more, preferably 1.05 equivalents or more, and more preferably 1.1 equivalents or more. Also, from the viewpoint of low cost, the amount of halogenated toluenesulfonic acid (B) relative to the carboxyl groups of carboxylic acid (A) is less than 2.0 equivalents, preferably 1.5 equivalents or less, and more preferably 1.3 equivalents or less.

[0093] The above mixture is used to react (A) a carboxylic acid and (B) a halogen of toluenesulfonic acid in the presence of (C) a first tertiary amine compound. The reaction conditions are not particularly limited. For example, the reaction temperature may be, for example, -50°C or higher. Alternatively, the reaction temperature may be, for example, 20°C or lower, preferably 10°C or lower, and more preferably 5°C or lower. The reaction time may be, for example, 5 minutes or more, preferably 30 minutes or more. Alternatively, the reaction time may be, for example, 6 hours or less, preferably 3 hours or less.

[0094] In the first reaction, the first intermediate product is obtained. More specifically, in the first reaction, in the presence of (C) the first tertiary amino compound (Base 1) as a base, toluenesulfonic acid (Ts) is added to the carboxyl group (-COOH) of (A) the carboxylic acid, forming the first adduct (-COO-Ts). As a result, in the first reaction, the first adduct (-COO-Ts) is obtained as the first intermediate product.

[0095] [Second reaction] The second reaction involves reacting the first intermediate product with (D) the second tertiary amine compound to obtain the second intermediate product.

[0096] More specifically, in the second reaction, for example, the first intermediate product is mixed with (D) the second tertiary amine compound. The mixing ratio of the first intermediate product and (D) the second tertiary amine compound is adjusted based on the equivalent ratio of (D) the second tertiary amine compound to the carboxyl group of (A) carboxylic acid (the (A) carboxylic acid used in the first reaction) (second tertiary amine compound / carboxyl group).

[0097] More specifically, from the viewpoint of reaction efficiency, the amount of (D) the second tertiary amine compound relative to the carboxyl group of (A) the carboxylic acid is 1.0 equivalent or more, preferably 1.05 equivalent or more, and more preferably 1.1 equivalent or more. Also, from the viewpoint of resistance to yellowing, the amount of (D) the second tertiary amine compound relative to the carboxyl group of (A) the carboxylic acid is less than 2.0 equivalents, preferably 1.5 equivalents or less, and more preferably 1.3 equivalents or less.

[0098] Furthermore, from the viewpoint of reaction efficiency, the total amount of (C) the first tertiary amine compound and (D) the second tertiary amine compound relative to the carboxyl group of (A) the carboxylic acid is 2.0 equivalents or more, preferably 2.1 equivalents or more, and more preferably 2.2 equivalents or more. Furthermore, from the viewpoint of low cost and resistance to yellowing, the total amount of (C) the first tertiary amine compound and (D) the second tertiary amine compound relative to the carboxyl group of (A) the carboxylic acid is less than 3.0 equivalents, preferably 2.8 equivalents or less, more preferably 2.5 equivalents or less, and even more preferably 2.3 equivalents or less.

[0099] Furthermore, from the viewpoint of reaction efficiency and low cost, the ratio of the number of moles of (D) the second tertiary amine compound to the number of moles of (C) the first tertiary amine compound ((D) number of moles of the second tertiary amine compound / (C) the first tertiary amine compound) is, for example, 0.1 or more and 10.0 or less, preferably 0.2 or more and 5.0 or less, more preferably 0.5 or more and 2.0 or less, and even more preferably greater than 1.0 and 1.8 or less.

[0100] The above mixture is used to react the first intermediate product with (D) the second tertiary amine compound. The reaction conditions are not particularly limited. For example, the reaction temperature may be, for example, -50°C or higher. Alternatively, the reaction temperature may be, for example, 20°C or lower, preferably 10°C or lower, and more preferably 5°C or lower. The reaction time may be, for example, 5 minutes or more, preferably 30 minutes or more. Alternatively, the reaction time may be, for example, 6 hours or less, preferably 3 hours or less.

[0101] In the second reaction, a second intermediate product is obtained. More specifically, in the above reaction, the first adduct (-COO-Ts), which is the first intermediate product, is substituted by (D) the second tertiary amine compound (Base2). As a result, (D) the second tertiary amine compound (Base2) is added to the carbonyl group (-CO-) of the carboxylic acid (A), forming the second adduct (-CO-Base2). Consequently, in the second reaction, the second adduct (-CO-Base2) is obtained as the second intermediate product.

[0102] [Third reaction] The third reaction involves reacting the second intermediate product with (E)thiol to obtain a thioester compound.

[0103] More specifically, in the third reaction, for example, the second intermediate product and (E) thiol are mixed. The mixing ratio of the second intermediate product and (E) thiol is not particularly limited, but is adjusted, for example, based on the equivalent ratio (carboxyl group / mercapto group) of the carboxyl group of (A) carboxylic acid (the (A) carboxylic acid used in the first reaction) to the mercapto group of (E) thiol.

[0104] More specifically, from the viewpoint of reaction efficiency, the amount of carboxyl groups of (A) carboxylic acid (the (A) carboxylic acid used in the first reaction) relative to the mercapto groups of (E) thiol is 1.0 equivalent or more, preferably 1.05 equivalents or more, and more preferably 1.1 equivalents or more. Also, from the viewpoint of resistance to yellowing, the amount of carboxyl groups of (A) carboxylic acid (the (A) carboxylic acid used in the first reaction) relative to the mercapto groups of (E) thiol is less than 2.0 equivalents, preferably 1.5 equivalents or less, and more preferably 1.3 equivalents or less.

[0105] The above mixture is used to react the second intermediate product with (E)thiol. The reaction conditions are not particularly limited. For example, the reaction temperature may be -50°C or higher. Alternatively, the reaction temperature may be 20°C or lower, preferably 10°C or lower, and more preferably 5°C or lower. The reaction time may be 5 minutes or more, preferably 30 minutes or more. Alternatively, the reaction time may be 6 hours or less, preferably 3 hours or less.

[0106] In the third reaction, a reaction product containing a thioester compound is obtained. More specifically, in the third reaction, the second adduct (-CO-Base2), which is the second intermediate product, is substituted by (E) thiol. As a result, the thioalkoxy group (-SR) of (E) thiol is added to the carbonyl group (-CO-) of (A) carboxylic acid, forming the third adduct (-CO-SR). Consequently, in the third reaction, a thioester compound having a thioester structure (-CO-S-) is obtained.

[0107] As described above, a thioester compound is obtained by reacting the starting components, which include (A) a carboxylic acid, (B) a halogenated toluenesulfonic acid, (C) a first tertiary amine compound, (D) a second tertiary amine compound, and (E) a thiol, in a reaction step.

[0108] [purification] The thioester compounds are purified by known methods as needed (purification step). The purification methods are not particularly limited and include, for example, washing, dehydration, impurity adsorption, liquid-liquid extraction, distillation, and recrystallization. These may be used individually or in combination of two or more.

[0109] [Reaction sequence] The reaction order in the reaction process is not particularly limited. For example, as described above, the raw material components may be supplied sequentially to the first and second reactions, and then to the third reaction after the completion of the first and second reactions.

[0110] More specifically, the raw material components may be subjected to the first reaction before the start of the second reaction and before the start of the third reaction (first reaction step). Also, the raw material components may be subjected to the second reaction after the completion of the first reaction and before the start of the third reaction (second reaction step). Also, the raw material components may be subjected to the third reaction after the completion of the first reaction and after the completion of the second reaction (third reaction step).

[0111] Furthermore, for example, the raw material components may be used simultaneously in the first and second reactions (a single reaction step), and then used in the third reaction after the completion of the first and second reactions.

[0112] In such cases, for example, first, the above-mentioned (A) carboxylic acid, (C) the first tertiary amine compound, and (D) the second tertiary amine compound are mixed in the above proportions and under the above conditions. This yields a single mixture containing (A) the carboxylic acid, (C) the first tertiary amine compound, and (D) the second tertiary amine compound.

[0113] Next, in this method, the above-mentioned aggregate mixture and (B) a halogenated toluenesulfonic acid are mixed in the above proportions and under the above conditions.

[0114] As a result, in the presence of (C) the first tertiary amine compound, (A) the carboxylic acid and (B) the halogen of toluenesulfonic acid react (first reaction), producing a first intermediate product. Furthermore, as the first reaction progresses, the generated first intermediate product reacts with (D) the second tertiary amine compound (second reaction), producing a second intermediate product. In other words, the starting components are used simultaneously in both the first and second reactions.

[0115] Subsequently, in this method, the second intermediate product and (E) thiol are mixed in the above proportions and under the above conditions. This causes the second intermediate product and (E) thiol to react (third reaction), producing a thioester compound.

[0116] In other words, as described above, a thioester compound can also be produced when the raw material components are used simultaneously in the first and second reactions, and then in the third reaction.

[0117] Furthermore, the reaction sequence in the reaction process is not limited to the above. For example, the first reaction may be carried out first to obtain the first intermediate product, and then (D) the second tertiary amine compound and (E) the thiol may be added simultaneously to the first intermediate product. In such a case, the second reaction proceeds as well as the third reaction proceeds, and a thioester compound is produced.

[0118] In other words, thioester compounds can also be produced when the raw material components are used in the first reaction, and then simultaneously in the second and third reactions.

[0119] Furthermore, for example, (A) a carboxylic acid, (B) a halogenated toluenesulfonic acid, (C) a first tertiary amine compound, (D) a second tertiary amine compound, and (E) a thiol can be mixed together. In such a case, the first reaction described above proceeds, as does the second reaction described above, producing a second intermediate product. Furthermore, as the second reaction proceeds, the third reaction proceeds, producing a thioester compound.

[0120] In other words, thioester compounds are produced even when the raw material components are used simultaneously in the first, second, and third reactions.

[0121] From the viewpoint of reaction efficiency, the raw material components are preferably first supplied sequentially or simultaneously to the first and second reactions, and then supplied to the third reaction after the completion of the first and second reactions. From the viewpoint of reaction efficiency, the raw material components are more preferably supplied sequentially to the first, second, and third reactions. That is, the raw material components are more preferably supplied to the first reaction before the start of the second and third reactions, supplied to the second reaction after the completion of the first reaction and before the start of the third reaction, and supplied to the third reaction after the completion of the first and second reactions. This allows for the acquisition of thioester compounds in a relatively short time and with excellent yield.

[0122] 2. Thioester compounds Thioester compounds are not particularly limited as long as they have a thioester bond (-C(=O)-S-), but for example, they are represented by the following general formula (1). General formula (1);

[0123] [ka] (In formula (1), A represents an n-valent organic group containing a sulfur atom. n represents an integer of 1 or more. S represents a sulfur atom. X represents a carbonyl group (-C(=O)-). R represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an aromatic aliphatic hydrocarbon group. R may have substituents. R may be the same as or different from one another.)

[0124] In formula (1) above, A represents an n-valent organic group containing a sulfur atom. n is the valency of A. n represents an integer of 1 or more. Preferably, n represents an integer between 3 and 8. More preferably, n represents an integer between 3 and 6. Even more preferably, n represents 3 or 4. More specifically, an n-valent A is a residue of the above (E) thiol. In other words, A is a residue obtained by removing the mercapto group from the above (E) thiol. Preferably, A is a residue obtained by removing the mercapto group from a (E) thiol with three or more functions.

[0125] In formula (1) above, the molecular weight of A is, for example, 50 or more, preferably 60 or more, more preferably 100 or more, and even more preferably 130 or more. Also, in formula (1) above, the molecular weight of A is, for example, 9000 or less, preferably 4000 or less, and even more preferably 500 or less. That is, in formula (1) above, the molecular weight of A is, for example, 50 or more and 9000 or less, preferably 60 or more and 4000 or less, more preferably 100 or more and 500 or less, and even more preferably 130 or more and 500 or less.

[0126] The molecular weight of A is calculated based on the molecular skeleton and number of atoms of (E) thiol in the raw material components. Specifically, the molecular weight of A is the molecular weight of the residue obtained by removing the mercapto group from (E) thiol.

[0127] Furthermore, the molecular weight of A can also be calculated, for example, by subtracting the molecular weight of (SXR)n from the molecular weight of the thioester compound represented by formula (1) above. The method for measuring the molecular weight of the thioester compound represented by formula (1) above is not particularly limited. For example, if the compound represented by formula (1) above is a monomer, the molecular weight of the thioester compound represented by formula (1) above is calculated from the molecular skeleton and the number of atoms. If multiple thioester compounds represented by formula (1) above are used in combination, the molecular weight of the compound represented by formula (1) above is calculated as the average value of the molecular weights of each thioester compound (the same applies hereinafter). Furthermore, if the thioester compound represented by formula (1) above is a polymer, the molecular weight of the compound represented by formula (1) above can be measured as the polystyrene-equivalent molecular weight by gel permeation chromatography (GPC) (the same applies hereinafter).

[0128] More preferably, A is a residue obtained by removing the mercapto group from the above-mentioned sulfide-containing aliphatic trithiol, and even more preferably, a residue obtained by removing the mercapto group from 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane (GST) (GST residue).

[0129] Furthermore, A is more preferably a residue obtained by removing the mercapto group from the above-mentioned sulfide-containing aliphatic tetrathiol, and even more preferably a residue (FSH residue) obtained by removing the mercapto group from 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane (FSH).

[0130] In formula (1) above, S represents a sulfur atom. Also, in formula (1) above, X represents a carbonyl group. That is, in formula (1) above, SX represents a thioester bond (-C(=O)-S-).

[0131] In formula (1) above, R is the residue obtained by removing the carboxyl group (-C(=O)OH) from (A) carboxylic acid. R represents an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an aromatic aliphatic hydrocarbon group. Examples of aliphatic hydrocarbon groups include aliphatic hydrocarbon groups having 1 to 20 carbon atoms. More specifically, examples of aliphatic hydrocarbon groups include linear aliphatic hydrocarbon groups having 1 to 20 carbon atoms and cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms. Examples of cyclic aliphatic hydrocarbon groups having 3 to 20 carbon atoms include cyclic saturated aliphatic hydrocarbon groups having 3 to 20 carbon atoms and cyclic unsaturated aliphatic hydrocarbon groups having 3 to 20 carbon atoms. Examples of aromatic hydrocarbon groups include aromatic hydrocarbon groups having 6 to 20 carbon atoms. Examples of aromatic aliphatic hydrocarbon groups include aromatic aliphatic hydrocarbon groups having 7 to 20 carbon atoms. These can be used individually or in combination of two or more types. In the above formula (1), R is preferably a methyl group, a phenyl group, a benzyl group, and a 2-phenylethyl group.

[0132] Aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and aromatic aliphatic hydrocarbon groups may have substituents. Examples of substituents include halogeno groups, cyano groups, amino groups, carboxyl groups, sulfonyl groups, alkoxy groups, aryloxy groups, and arylalkyloxy groups. These may be used alone or in combination of two or more. Preferably, substituents include aryloxy groups and arylalkyloxy groups. That is, R in formula (1) above may have an aryloxy group and / or an arylalkyloxy group. Examples of aryloxy groups include aryloxy groups having 6 to 20 carbon atoms, more specifically, phenoxy groups (-O-C6H5) and naphthyloxy groups (-OC 10Examples include H7). The arylalkyloxy group is a substituent having an oxygen atom (O) directly bonded to the hydrocarbon group (i.e., the aliphatic hydrocarbon group, the aromatic hydrocarbon group, or the aromatic aliphatic hydrocarbon group), an alkylene group bonded to that oxygen atom, and an aromatic ring bonded to the alkylene group (-O-alkylene group-aromatic ring). Examples of arylalkyloxy groups include arylalkyloxy groups having 7 to 20 carbon atoms, and more specifically, benzyloxy groups (-O-CH2-C6H5). These can be used alone or in combination of two or more. Preferably, an aryloxy group is used, and more preferably, a phenoxy group is used. The number of substituents is set appropriately depending on the purpose and application. The substitution position is set appropriately depending on the purpose and application.

[0133] The compound of formula (1) above comprises three or more SXR groups, depending on the value of n. The R groups in each SXR group may be the same or different. Preferably, one selected from the group consisting of aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and aromatic aliphatic hydrocarbon groups is used alone. That is, preferably, in formula (1) above, the R groups in each SXR group are the same.

[0134] Preferably, compounds represented by formula (1) above include compounds in which A in formula (1) is a GST residue. Compounds in which A in formula (1) is a GST residue are represented, for example, by the following general formula (2). General formula (2);

[0135] [ka] (In equation (2), S, X, and R have the same meanings as S, X, and R in equation (1). In equation (2), the portion enclosed by the dashed line represents the organic group A (n=3) in equation (1).)

[0136] More specifically, a compound represented by formula (2) above is 4-benzoylthiomethyl-1,8-bisbenzoylthio-3,6-dithiaoctane (Bz-GST). In Bz-GST, X in formula (2) represents a carbonyl group, and R represents a phenyl group.

[0137] Furthermore, a more specific example of the compound represented by formula (2) above is 4-acetylthiomethyl-1,8-bisacetylthio-3,6-dithiaoctane (Ac-GST). In Ac-GST, X in formula (2) represents a carbonyl group, and R represents a methyl group.

[0138] Furthermore, a more specific example of the compound represented by formula (2) above is 4-phenylacetylthiomethyl-1,8-bisphenylacetylthio-3,6-dithiaoctane (PA-GST). In PA-GST, X in formula (2) represents a carbonyl group, and R represents a benzyl group.

[0139] Furthermore, a more specific example of the compound represented by formula (2) above is 4-(3-phenylpropionyl)thiomethyl-1,8-bis(3-phenylpropionyl)thio-3,6-dithiaoctane (PP-GST). In PP-GST, X in formula (2) represents a carbonyl group, and R represents a 2-phenylethyl group.

[0140] Furthermore, as compounds represented by formula (1) above, preferably, compounds in which A in formula (1) is an FSH residue are mentioned. Compounds in which A in formula (1) is an FSH residue are represented, for example, by the following general formula (3). General formula (3);

[0141] [ka] (In equation (3), S, X, and R have the same meanings as S, X, and R in equation (1). In equation (3), the portion enclosed by the dashed line represents the organic group A (n=4) in equation (1).)

[0142] According to the compound shown in formula (3) above, a cured product can be obtained that possesses particularly excellent refractive index and particularly excellent flexibility.

[0143] More specifically, the compound represented by formula (3) above is 5,7-bis(benzoylmercaptomethyl)-1,11-bis(benzoylmercapto)-3,6,9-trithiaundecane (Bz-FSH). In Bz-FSH, X in formula (3) represents a single bond, and R represents a benzyl group.

[0144] 3. Effects (1) Yield According to the above method for producing thioester compounds, thioester compounds (total adducts) in which all mercapto groups of thiol are thioesterified can be obtained in relatively high yield. In other words, the above thioester compounds contain a relatively high proportion of thioester compounds (total adducts) in which all mercapto groups of thiol are thioesterified.

[0145] More specifically, in the production of thioester compounds, it is desirable that (A) carboxylic acid be added to all of the mercapto groups of (E) thiol to form a thioester bond (-C(=O)-S-).

[0146] However, depending on the manufacturing method, (A) carboxylic acid may not be added to some of the mercapto groups of (E) thiol. In other words, the yield of the product in which all of the mercapto groups of (E) thioesterified (total adduct) may decrease.

[0147] In contrast, the above method for producing thioester compounds uses (C) a first tertiary amine compound and (D) a second tertiary amine compound in predetermined proportions. This promotes the formation of thioester bonds (-C(=O)-S-). As a result, the yield of thioester compounds (total adducts) in which all mercapto groups of the (E) thiol are thioesterified can be improved.

[0148] The yield of the thioester compound (total adduct) in which all mercapto groups of (E) thiol are thioesterified is, for example, the ratio of the thioester compound (total adduct) in which all mercapto groups of (E) thiol are thioesterified relative to the total amount of (E) thiol used as a starting material. The yield of the thioester compound (total adduct) in which all mercapto groups of (E) thiol are thioesterified is calculated, for example, by the following method.

[0149] For example, if (E) thiol has three mercapto groups, the reaction products in the above reaction can be expected to be a compound in which (A) carboxylic acid is attached to all (3) mercapto groups (total adduct), a compound in which (A) carboxylic acid is attached to only two mercapto groups (dipduct), a compound in which (A) carboxylic acid is attached to only one mercapto group (one adduct), and a compound in which (A) carboxylic acid is not attached to any of the mercapto groups (no adduct).

[0150] In such cases, the reaction products in the above-mentioned method for producing the thioester compound can be measured by liquid chromatography according to the examples described later, and the relationship between each peak and each adduct can be identified by known methods. Furthermore, the peak area of ​​the peak corresponding to all adducts, the peak area of ​​the peak corresponding to two adducts, the peak area of ​​the peak corresponding to one adduct, and the peak area of ​​the peak corresponding to no adduct can be measured. Then, the peak area of ​​the peak corresponding to all adducts can be calculated relative to the total amount of these peak areas, and the obtained result can be used as the yield (area %) of the thioester compound (total adduct) in which all mercapto groups of (E) thiol have been thioesterified. Note that the above calculation is performed similarly depending on the number of mercapto groups that (E) thiol has.

[0151] The yield of the thioester compound (total adduct) in which all mercapto groups of (E) thiol are thioesterified is, for example, 90% or more, preferably 95% or more, and more preferably 97% or more. Alternatively, the yield of the thioester compound (total adduct) in which all mercapto groups of (E) thiol are thioesterified is, for example, 100% or less. (2) Yellowness The above method for producing thioester compounds allows for the production of thioester compounds with relatively low yellowness at a relatively low cost. In other words, the above thioester compounds are produced at a relatively low cost and have relatively low yellowness.

[0152] More specifically, it is desirable that the thioester compound has a relatively low degree of yellowness.

[0153] However, depending on the manufacturing method, the proportion of tertiary amine compounds as unavoidable impurities relative to the thioester compounds may be relatively high, resulting in the thioester compounds having a relatively high degree of yellowness.

[0154] In contrast, the above-described method for producing thioester compounds uses (C) a first tertiary amine compound and (D) a second tertiary amine compound in predetermined proportions. Therefore, the proportion of tertiary amine compounds, which are unavoidable impurities, can be kept relatively low. As a result, the thioester compounds have a relatively low degree of yellowness.

[0155] For example, the content of (C) the first amine compound (i.e., a tertiary amine compound in which the acid dissociation constant (pKa1) of the conjugate acid is above a predetermined value) is, for example, 1 ppm or more, preferably 10 ppm or more, relative to the total amount of thioester compounds. Alternatively, for example, the content of (C) the first amine compound (i.e., a tertiary amine compound in which the acid dissociation constant (pKa1) of the conjugate acid is above a predetermined value) is, for example, 1000 ppm or less, preferably 100 ppm or less, relative to the total amount of thioester compounds.

[0156] Furthermore, for example, the content of (D) the second amine compound (i.e., a ring structure-containing amine having two or more tertiary amino groups in one molecule) is, for example, 1 ppm or more, preferably 10 ppm or more, relative to the total amount of the thioester compound. Furthermore, for example, the content of (D) the second amine compound (i.e., a ring structure-containing amine having two or more tertiary amino groups in one molecule) is, for example, 1000 ppm or less, preferably 100 ppm or less, relative to the total amount of the thioester compound.

[0157] The yellowness of the thioester compound is evaluated by the yellow index (YI value). The yellow index (YI value) of the thioester compound is, for example, 7.0 or less, preferably 6.0 or less, more preferably 5.0 or less, and even more preferably 4.0 or less. The yellow index (YI value) of the thioester compound is usually 0.1 or higher. The yellow index (YI value) of the thioester compound is measured using a spectrochromator in accordance with the examples described later.

[0158] The thioester compounds described above are not particularly limited and are widely used in various industrial fields where thioester compounds are required. Examples of applications for thioester compounds include plasticizers and refractive index modifiers for molded resin products. Other applications of thioester compounds include raw materials, intermediates, and modifiers for various products. Examples of such products include adhesive compositions, paints, modifiers, films, polymers, pharmaceuticals, pesticides, and cosmetics. Preferably, applications of thioester compounds include plasticizers and refractive index modifiers for molded resin products. [Examples]

[0159] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" and "%" refer to mass. Furthermore, specific numerical values ​​such as blending ratios (content percentages), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the blending ratios (content percentages), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0160] 1.Measurement method The conditions for liquid chromatography (LC) and yellow index (YI value) measurement used in the examples are shown below.

[0161] <Liquid chromatography (LC) measurement> • Column: YMC-Pack ODS-A (manufactured by YMC, ODS column) • Detector: Ultraviolet-Visible (UV) detector • Detection wavelength: 200nm Mobile phase: Acetonitrile / 0.1% phosphoric acid aqueous solution (95:5 → 100:0) ·Flow rate: 1.0mL / min Oven temperature: 40℃

[0162] <Yellow Index (YI value) measurement> • Equipment: COH-7700 (manufactured by Nippon Denshoku Industries, Spectrochromatic Color Haze Meter) • Cell thickness: 2mm • Solvent dilution: None

[0163] 2.Individual addition <Example 1> (1) First reaction step 3-phenylpropionic acid ((A)carboxylic acid, 54.1 g, 360 mmol) was dissolved in 100 mL of acetonitrile (solvent) to obtain a solution of carboxylic acid. The solution of carboxylic acid was then placed in a four-necked flask equipped with a stirrer, thermometer, nitrogen introduction line, and dropping funnel.

[0164] Next, triethylamine ((C) the first tertiary amine compound, 36.4 g, 360 mmol, 1.0 equivalent (hereinafter, eq) relative to the carboxyl group of the carboxylic acid, pKa of the conjugate acid 10.7) was added to the solution of the carboxylic acid. This yielded the first mixture. The first mixture was then cooled in an ice bath, maintaining the internal temperature of the flask below 5°C.

[0165] Next, p-toluenesulfonic acid chloride ((B) toluenesulfonic acid halogen, 75.5 g, 396 mmol, 1.1 eq relative to the carboxyl group of the carboxylic acid) was dissolved in 300 mL of acetonitrile to obtain a solution of toluenesulfonic acid halogen.

[0166] Next, a solution of toluenesulfonic acid halide was added dropwise to the first mixture, maintaining the internal temperature of the flask below 5°C. The addition time was 20 minutes. The contents of the flask were then stirred at the same temperature for 30 minutes.

[0167] This allowed (A) the carboxylic acid and (B) the halide of toluenesulfonic acid to react in the presence of (C) the first tertiary amine compound (first reaction). As a result, the first intermediate product was obtained.

[0168] (2) Second reaction step Next, N-methylimidazole ((D) second tertiary amine compound, 35.5 g, 432 mmol, 1.2 eq relative to the carboxyl group of the carboxylic acid) was added dropwise to the first intermediate product, ensuring that the internal temperature of the flask was maintained below 5°C. The addition time was 5 minutes. After that, the contents of the flask were stirred at the same temperature for 30 minutes.

[0169] This allowed the first intermediate product to react with (D) the second tertiary amine compound (second reaction). As a result, the second intermediate product was obtained.

[0170] (3) Third reaction step Next, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane ((E)thiol, abbreviated as GST, 26.1 g, 100 mmol, 3 functional groups (300 mmol mercapto group)) was added dropwise to the second intermediate product, while maintaining the internal temperature of the flask below 5°C. The addition time was 5 minutes. The contents of the flask were then stirred at the same temperature for 1 hour. This allowed the second intermediate product to react with the (E)thiol, yielding the reaction product.

[0171] In the above reaction, the ratio of carboxyl groups in (A) carboxylic acid (3-phenylpropionic acid) to mercapto groups in (E) thiol (GST) (carboxyl groups / mercapto groups) was 1.2.

[0172] (E) The reaction product after adding thiol and stirring for 1 hour was LC and 1 The reaction product was analyzed by 1H-NMR. The results confirmed that the reaction product contained PP-GST (a thioester compound, 4-(3-phenylpropionyl)thiomethyl-1,8-bis(3-phenylpropionyl)thio-3,6-dithiaoctane, an adduct formed by the addition of three carboxylic acid molecules to GST (hereinafter referred to as the tripadduct)).

[0173] On the other hand, in LC, no peaks corresponding to the adduct formed by the addition of two carboxylic acid molecules to GST (hereinafter referred to as the 2-adduct), the adduct formed by the addition of one carboxylic acid molecule to GST (hereinafter referred to as the 1-adduct), or the unadducted form of GST (without any carboxylic acid added) were observed.

[0174] In other words, in the reaction product after adding (E) thiol and stirring for 1 hour, the ratio of the 3-adduct to the total amount of the no-adduct, 1-adduct, 2-adduct, and 3-adduct (3-adduct yield) was 100%. Furthermore, in Example 1, the total time required to achieve a 100% yield of the 3-adduct was approximately 2 hours and 30 minutes.

[0175] PP-GST (a triplicate of GST) has a structure in which 3-phenylpropionic acid is attached to all three of the mercapto groups of GST. Furthermore, the diadduct of GST has a structure in which 3-phenylpropionic acid is attached to only two of the three mercapto groups of GST. The hepoadduct of GST has a structure in which 3-phenylpropionic acid is attached to only one of the three mercapto groups of GST. The unadducted form of GST is simply GST.

[0176] (4) Purification process The majority of the acetonitrile was removed from the reaction product by concentration using a rotary evaporator to obtain a residue. The residue was then diluted with 200 mL of toluene to obtain a diluent.

[0177] Next, 200 mL of a 10% sodium chloride aqueous solution was added to the diluent to obtain a mixture. Then, the organic phase was separated from the mixture by liquid-liquid separation. The organic phase was a toluene solution of the reaction product (hereinafter referred to as the reaction product solution).

[0178] Next, the reaction product solution was washed with 200 mL of 1N dilute hydrochloric acid, then with 200 mL of saturated sodium bicarbonate aqueous solution, and finally with 200 mL of pure water.

[0179] The solution of the reaction product after washing was passed through activated alumina (300 mesh, for chromatography, basic). After passing through, 200 mL of toluene was used to flush out any remaining reaction product from the alumina.

[0180] After the reaction product solution was passed through, anhydrous sodium sulfate was added and stirred to remove any remaining water from the solution. Then, the sodium sulfate was filtered off using pleated filter paper.

[0181] By concentration using an evaporator, most of the toluene was removed from the filtered solution (filtrate) of the reaction product to obtain a residue. The residue was dried in a vacuum dryer to remove residual toluene. This purified the reaction product and obtained a purified product.

[0182] The purified product was a pale yellow liquid with a Yellow Index (YI value) of 3.7. The yield was 57.7 g, and the yield was 88% by mass.

[0183] <Examples 3-10 and Comparative Examples 3-5> Except for the formulation shown in Table 1, the reaction was carried out in the same manner as in Example 1, with (A) carboxylic acid, (B) toluenesulfonic acid halogen, (C) a first tertiary amine compound, (D) a second tertiary amine compound, and (E) thiol being reacted to obtain a reaction product. The obtained reaction product was then purified in the same manner as in Example 1 to obtain a purified product.

[0184] Then, using the reaction product after adding (E) thiol and stirring for 1 hour, the no adduct, adduct 1, adduct 2, and adduct 3 were identified based on the retention time by LC. In addition, the ratio of the adduct 3 to the total amount of the no adduct, adduct 1, adduct 2, and adduct 3 (yield of the adduct 3) was calculated in the reaction product after adding (E) thiol and stirring for 1 hour.

[0185] In Example 8, as in Example 1, the reaction product was subjected to LC and 1Analysis was performed by 1H-NMR. As a result, Bz-GST (thioester compound, 4-benzoylthiomethyl-1,8-bisbenzoylthio-3,6-dithiaoctane (hereinafter, the 3-adduct)) was identified instead of PP-GST. Furthermore, in the LC of Example 8, no peaks corresponding to the adduct with two molecules of carboxylic acid added to GST (hereinafter, the 2-adduct), the adduct with one molecule of carboxylic acid added to GST (hereinafter, the 1-adduct), or the unadducted form (without carboxylic acid added to GST) were observed. In other words, the yield of the 3-adduct in Example 8 was 100%.

[0186] 3. Add all at once <Example 2> (1) Batch reaction process 3-phenylpropionic acid ((A)carboxylic acid, 2.7 g, 18 mmol) was dissolved in 5 mL of acetonitrile to obtain a solution of carboxylic acid. The solution of carboxylic acid was then placed in a four-necked flask equipped with a stirrer, thermometer, nitrogen introduction line, and dropping funnel.

[0187] Next, triethylamine ((C) the first tertiary amine compound, 1.8 g, 18 mmol, 1 eq relative to the carboxyl group of the carboxylic acid) and N-methylimidazole ((D) the second tertiary amine compound, 1.8 g, 22 mmol, 1.2 eq relative to the carboxyl group of the carboxylic acid) were added together to the solution of the carboxylic acid. This yielded a single mixture. Next, the entire mixture was cooled in an ice bath to maintain the internal temperature of the flask at 5°C or below.

[0188] Next, p-toluenesulfonic acid chloride ((B) toluenesulfonic acid halogen, 3.8 g, 20 mmol, 1.1 eq relative to the carboxyl group of the carboxylic acid) was dissolved in 15 mL of acetonitrile to obtain a solution of toluenesulfonic acid halogen.

[0189] Next, a solution of toluenesulfonic acid halide was added dropwise to the mixture, maintaining the internal temperature of the flask below 5°C. The addition time was 5 minutes. The contents of the flask were then stirred at the same temperature for 30 minutes.

[0190] Next, 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane ((E)thiol, abbreviated as GST, 1.3 g, 5 mmol, 3 functional groups (15 mmol mercapto group)) was added dropwise to the mixture, ensuring that the internal temperature of the flask was maintained below 5°C. The addition time was 5 minutes. The contents of the flask were then stirred at the same temperature for 1 hour. This yielded the reaction product.

[0191] (E) The reaction product after adding thiol and stirring for 1 hour was LC and 1 Analysis was performed using 1H-NMR. The results confirmed that the reaction product contained PP-GST (a triadduct of GST). Furthermore, the retention times and peak area values ​​of each peak in LC confirmed that the reaction product also contained a diadduct.

[0192] On the other hand, in LC, no peaks corresponding to one adduct of GST, nor a peak corresponding to the unadducted GST, were observed.

[0193] (E) The yields of the diadduct and triadduct in the reaction product after thiol addition and stirring for 1 hour were calculated based on the peak area values ​​obtained by LC analysis.

[0194] As a result, the proportion of the diadduct relative to the total amount of the unadducted compound, 1-adduct, 2-adduct, and 3-adduct (yield of the 2-adduct) was approximately 3%. Furthermore, the proportion of the 3-adduct relative to the total amount of the unadducted compound, 1-adduct, 2-adduct, and 3-adduct (yield of the 3-adduct) was approximately 97%.

[0195] Furthermore, the reaction product was stirred for a further 3 hours (total stirring time of 4 hours). The reaction product was then analyzed using the same method as described above. The results confirmed that the reaction product contained PP-GST (a triadduct of GST). However, in LC, no peaks corresponding to the diadduct of GST, the headduct of GST, or the unadducted GST were observed.

[0196] In other words, in the reaction product after adding (E) thiol and stirring for 4 hours, the proportion of the 3-adduct (yield of the 3-adduct) to the total amount of the no-adduct, 1-adduct, 2-adduct, and 3-adduct was 100%. Furthermore, in Example 2, the total time required to achieve a 100% yield of the 3-adduct was approximately 4 hours and 40 minutes.

[0197] <Comparative Example 1> Except for the formulation shown in Table 1, the reaction product was obtained by reacting (A) a carboxylic acid, (B) a halogenated toluenesulfonic acid, (C) a first tertiary amine compound, and (E) a thiol in the same manner as in Example 2.

[0198] (E) The reaction product after adding thiol and stirring for 1 hour was LC and 1 Analysis was performed by 1H-NMR. The results confirmed that the reaction product contained PP-GST (a thioester compound, a triplicate of 4-(3-phenylpropionyl)thiomethyl-1,8-bis(3-phenylpropionyl)thio-3,6-dithiaoctane and GST).

[0199] On the other hand, in LC, no peaks corresponding to the diadduct of GST, the iadduct of GST, or the unadducted GST were observed.

[0200] In other words, in the reaction product after the addition of (E) thiol and stirring for 1 hour, the yield (total thioesterification rate) of PP-GST (GST triadduct) relative to the total amount of GST was 100%.

[0201] Subsequently, the reaction product was purified using the same method as in the purification step of Example 1. This purified the reaction product and yielded a purified product. The purified product was a clear yellow liquid with a Yellow Index (YI value) of 7.3. The yield was 3.2 g, and the yield was 82% by mass.

[0202] <Comparative Example 2> Except for the formulation shown in Table 1, the reaction was carried out in the same manner as in Comparative Example 1, by reacting (A) a carboxylic acid, (B) a halogenated toluenesulfonic acid, (C) a first tertiary amine compound, and (E) a thiol to obtain a reaction product.

[0203] (E) The reaction product after adding thiol and stirring for 1 hour was LC and 1 Analysis was performed by 1H-NMR. The results confirmed that the reaction product contained PP-GST (a thioester compound, a triplicate of 4-(3-phenylpropionyl)thiomethyl-1,8-bis(3-phenylpropionyl)thio-3,6-dithiaoctane and GST).

[0204] Furthermore, the retention time and peak area values ​​of each peak in LC confirmed that the reaction product contains two adducts.

[0205] On the other hand, in LC, no peaks corresponding to one adduct of GST, nor a peak corresponding to the unadducted GST, were observed.

[0206] (E) The yields of the diadduct and triadduct in the reaction product after thiol addition and stirring for 1 hour were calculated based on the peak area values ​​of LC analysis. As a result, the yield of the diadduct relative to the total amount of GST was approximately 70%, and the yield of PP-GST (triadduct of GST) (total thioesterification rate) was approximately 30%.

[0207] Furthermore, even after adding (E) thiol and stirring for 1 hour, stirring was continued, but the yield (total thioesterification rate) of PP-GST (GST triadduct) did not increase.

[0208] <Rating> (1) Amount of amine compound The total equivalents of the first tertiary amine compound (equivalent to the carboxyl group of the carboxylic acid) and the second tertiary amine compound (equivalent to the carboxyl group of the carboxylic acid) are shown in Table 1. Furthermore, the total equivalents were evaluated according to the following criteria. The results are shown in Table 1.

[0209] ○; Less than 3.0 equivalents ×;3.0 equivalent or more

[0210] (2) Yield (E) In the reaction product after thiol addition and stirring for 1 hour, the ratio of the 3-adduct to the total amount of the 1-adduct, 2-adduct, and 3-adduct (3-adduct yield) is shown in Table 1. The 3-adduct yield was also evaluated according to the following criteria. The results are shown in Table 1.

[0211] ◎; Triad yield of 98% or more ○;3 Adduct yield 50% or more and less than 98% ×; yield of the triadduct is less than 50%

[0212] [Table 1]

[0213] Details of the abbreviations in the table are as follows. TEA; triethylamine, a ring-structure-free amine, conjugate acid pKa 10.7 DIPEA; N-ethyldiisopropylamine, ring-structure-free amine, conjugate acid pKa 11.4 TEDA; triethylenediamine, a ring-structure-containing amine, conjugate acid with a pKa of 8.7 NMM; N-methylmorpholine, a ring-structure-containing amine, conjugate acid pKa 7.8 NMIMZ; N-methylimidazole, ring-structure-containing amine, conjugate acid pKa 7.1 Pyr; pyridine, a ring-structure-containing amine, conjugate acid with a pKa of 5.4 DMAP; 4-dimethylaminopyridine, ring-structure-containing amine, conjugate acid pKa 9.9 DBN; diazabicyclononene, ring-structure-containing amine, conjugate acid pKa 13.5

[0214] <Consideration> The following points were considered from each example and each comparative example.

[0215] (1) Acid dissociation constant In Comparative Example 3, the thioesterification reaction did not proceed sufficiently. This was presumed to be because the pKa1 of the conjugate acid of the first tertiary amine compound was less than 7.8.

[0216] In particular, referring to Examples 1-3 and 6-7, it was inferred that if the pKa1 of the conjugate acid of the first tertiary amine compound is 10.0 or higher, the thioesterification reaction proceeds particularly well, and the triadduct is obtained with excellent efficiency.

[0217] Furthermore, referring to Examples 4-5, it was inferred that even if the pKa1 of the conjugate acid of the first tertiary amine compound is less than 10.0, if the pKa1 of the conjugate acid of the first tertiary amine compound is greater than the pKa2 of the conjugate acid of the second tertiary amine compound, the thioesterification reaction proceeds particularly well, and the triadduct is obtained with excellent efficiency.

[0218] (2)Chemical structure In Comparative Example 5, the thioesterification reaction did not proceed sufficiently. This was presumed to be because the second tertiary amine compound was an aliphatic amine compound. On the other hand, as can be seen from each example, it was presumed that if the second tertiary amine compound is a ring-structure-containing amine having two or more tertiary amino groups in one molecule, the thioesterification reaction proceeds well, and the tripycombate is obtained with excellent efficiency.

[0219] (3) Addition method In Example 1 and Example 2, although the method of adding the amine compound differed, the thioesterification reaction proceeded in both cases, and the triplicate was obtained. In other words, it was confirmed that the first tertiary amine compound and the second tertiary amine compound may be added together or individually.

[0220] On the other hand, the reaction time in Example 1 was significantly shorter than that in Example 2. In other words, it was confirmed that, from the viewpoint of shortening the reaction time and efficiently obtaining the triadduct, it is preferable to add the first tertiary amine compound and the second tertiary amine compound separately.

[0221] (4) Yellowness The YI value of Example 1 is significantly smaller than that of Comparative Example 1. This is presumed to be due to the fact that the total equivalent weight of the amine compounds in Example 1 (2.2 equivalents) is smaller than the total equivalent weight of the amine compounds in Comparative Example 1 (3.0 equivalents). In particular, this is presumed to be due to the fact that the equivalent weight of the ring-structure-containing amine (NMIMZ) in Example 1 (1.2 equivalents) is smaller than the total equivalent weight of the ring-structure-containing amine in Comparative Example 1 (3.0 equivalents).

[0222] The above invention is provided as an illustrative embodiment of the present invention, but this is merely illustrative and should not be interpreted restrictively. Modifications of the present invention that are obvious to those skilled in the art are included in the claims described below. [Industrial applicability]

[0223] The method for producing thioester compounds and the thioester compounds themselves are suitably used in various industrial fields, particularly in the fields of plasticizers and refractive index modifiers for molded resin products.

Claims

1. A method for producing thioester compounds, The process includes a reaction step that generates the thioester compound by the reaction of raw material components. The aforementioned raw material components are (A) Carboxylic acid and (B) Halides of toluenesulfonic acid, (C) The first tertiary amine compound, (D) A second tertiary amine compound, (E) Thiol and Includes, The reaction in the above reaction step is The first reaction involves reacting (A) a carboxylic acid with (B) a halogen of toluenesulfonic acid in the presence of (C) a first tertiary amine compound to obtain a first intermediate product. The first intermediate product is reacted with (D) a second tertiary amine compound to obtain a second intermediate product in a second reaction, A third reaction is carried out in which the second intermediate product is reacted with (E) thiol to obtain a thioester compound. Includes, The acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound (C) is 7.8 or greater. The (D) second tertiary amine compound includes a ring-structure-containing amine having two or more tertiary amino groups in one molecule. With respect to the carboxyl group of the carboxylic acid (A), The amount of the first tertiary amine compound (C) is 1.0 equivalent or more and less than 2.0 equivalents. The amount of the second tertiary amine compound (D) is 1.0 equivalent or more and less than 2.0 equivalents. The total amount of the first tertiary amine compound (C) and the second tertiary amine compound (D) is less than 3.0 equivalents. A method for producing thioester compounds.

2. In the reaction step, the raw material components are First, the first and second reactions are subjected sequentially or simultaneously, After the completion of the first and second reactions, the following is subjected to the third reaction: A method for producing a thioester compound according to claim 1.

3. In the reaction step, the raw material components are Before the start of the second reaction and before the start of the third reaction, the following is used in the first reaction: After the completion of the first reaction and before the commencement of the third reaction, the following is subjected to the second reaction: After the completion of the first reaction and the completion of the second reaction, the following is subjected to the third reaction: A method for producing a thioester compound according to claim 2.

4. The acid dissociation constant (pKa1) of the conjugate acid of the first tertiary amine compound (C) is greater than the acid dissociation constant (pKa2) of the conjugate acid of the second tertiary amine compound (D). A method for producing a thioester compound according to claim 1 or 2.

5. The above (C) first tertiary amine compound includes a ring structure-free amine, A method for producing a thioester compound according to claim 1 or 2.

6. The (D) second tertiary amine compound contains at least one selected from the group consisting of N-methylimidazole, 4-dimethylaminopyridine, and diazabicyclononene. A method for producing a thioester compound according to claim 1 or 2.

7. The (E) thiol contains an aliphatic thiol. A method for producing a thioester compound according to claim 1 or 2.

8. The (E) thiol has a sulfide bond, A method for producing a thioester compound according to claim 1 or 2.

9. The (E) thiol is 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane and 5,7-dimercaptomethyl-1,11-dimercapto-3,6 It contains at least one selected from the group consisting of 9-trithiaundecane, A method for producing a thioester compound according to claim 1 or 2.

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