Thiol production method

Abstract

In the thiol production method according to the present embodiment, thiol (2) is obtained by reacting an alkene (1) or a derivative thereof with sulfur in the presence of hydrogen and a metal element.

Description

Thiol production method

[0001] The present invention relates to a method for producing thiols. This application claims priority based on Japanese Patent Application No. 2023-034877, filed on March 7, 2023, the contents of which are incorporated herein by reference.

[0002] Thiols are used in a variety of applications, including as gas odorants, fragrances, and ligands. Examples of gas odorants include thiophenol, examples of fragrances include 3-mercaptohexanol, and examples of ligands include tert-butylthiol.

[0003] Conventionally, methods for producing thiols include, for example, (1) a substitution reaction (SN) in which reactants interact in one step. ２ (2) a synthesis method of thiols using hydrogen sulfide from an alcohol as a raw material (Non-Patent Document 2); (3) a synthesis method of thiols using hydrogen sulfide from an alkene as a raw material (Non-Patent Document 3); (4) a synthesis method of thiols using ultraviolet light or a platinum electrode from an alkene as a raw material (Non-Patent Document 4); and (5) a synthesis method of thiols using sulfur and a carbonyl compound (Non-Patent Document 5).

[0004] J. Org. Chem. 1968, 33, p1275-1276Catalysis Lett. 2000, 64, 197-200Ind. Eng. Chem. 1948, 40, No. 12, p2308-2313. J. Org. Chem. 1942, 07, 6, p472-476 Journal of the Chemical Society of Japan, 1987, 7, p1502-1504

[0005] However, the synthesis method (1) has low atomic efficiency and produces a large amount of waste as a by-product. The synthesis method (2) requires strict reaction conditions, such as high reaction temperatures, making production difficult. The synthesis method (3) requires the use of hydrogen sulfide, which is highly toxic and therefore requires complicated handling in terms of facility management, etc. Furthermore, the synthesis method (4) requires an ultraviolet irradiation device and expensive platinum electrodes, resulting in increased production costs. The synthesis method (5) requires the use of CO gas and an expensive organic base, which, like the synthesis methods (3) and (4), results in complicated handling of raw materials and increased production costs.

[0006] An object of the present invention is to provide a method for producing a thiol that can be easily produced with high atom efficiency, that allows easy handling of raw materials, and that can further reduce production costs.

[0007] To achieve the above object, the present inventors conducted extensive research and found that various thiols can be easily obtained by reacting sulfur and hydrogen with the carbon atom at the 2-position of an alkene having a terminal or partial double bond in the presence of a catalyst containing a metal element. In particular, by using hydrogen (gas), which is becoming increasingly available as a next-generation fuel, as a raw material, various thiols can be produced without using hydrogen sulfide gas, which is difficult to handle, or expensive organic bases, and without using an ultraviolet irradiation device, platinum electrodes, etc.

[0008] That is, the present invention provides the following means: [1] A method for producing a thiol, which comprises reacting an alkene (1) or a derivative thereof with sulfur in the presence of hydrogen and a metal element to obtain a thiol (2).

[0009] [2] The method for producing a thiol according to the above [1], wherein the pressure of hydrogen supplied when reacting the alkene (1) or a derivative thereof with sulfur is 0.1 MPa or more and 10 MPa or less.

[0010] [3] The method for producing a thiol according to the above [1] or [2], wherein the heating temperature when reacting the alkene (1) or a derivative thereof with sulfur in the presence of hydrogen is 100°C or higher and 200°C or lower.

[0011] [4] The method for producing a thiol according to any one of [1] to [3] above, wherein the metal element is one or more metal elements selected from groups 6 to 11.

[0012] [5] The method for producing a thiol according to the above [4], wherein the metal element is a metal element constituting a metal oxide or a metal sulfide.

[0013] [6] The method for producing a thiol according to any one of [1] to [5] above, wherein the amount of the metal element added to the alkene (1) or a derivative thereof is 0.1 mol % or more and 10 mol % or less.

[0014] [7] The method for producing a thiol according to any one of the above [1] to [6], wherein the alkene (1) or a derivative thereof is reacted with sulfur in the presence of hydrogen, the metal element, and a zeolite.

[0015] [8] The method for producing a thiol according to the above [7], wherein the zeolite is basic.

[0016] [9] The method for producing a thiol according to the above [7] or [8], wherein the zeolite has an X-type or A-type pore structure.

[0017]

[10] The method for producing a thiol according to any one of [7] to [9] above, wherein the amount of the zeolite added is 2.0 parts by mass or more and 25 parts by mass or less per 100 parts by mass of the alkene (1).

[0018]

[11] The alkene (1) is R １ R ２ C=CH ２ ...(A) (in the formula, R １ is an alkyl group, and R ２ is a hydrogen atom or an alkyl group, and R １ and R ２ The method for producing a thiol according to any one of the above [1] to

[10] , wherein the total number of carbon atoms is 2 to 20.

[0019]

[12] R in the above general formula (A) １ and R ２ The method for producing a thiol according to

[11] above, wherein the total number of carbon atoms is 2 to 16.

[0020] According to the present invention, it is possible to provide a method for producing a thiol that can be easily produced with high atom efficiency, that allows easy handling of raw materials, and that can further reduce production costs.

[0021] Fig. 1 is a schematic diagram showing the reaction in the method for producing thiol according to an embodiment of the present invention. Fig. 2 is a schematic diagram showing the reaction in the method for producing thiol (2a) in Example 1. Fig. 3 is a diagram showing the time course of the yield of thiol (2a) and the total yield of dialkyl monosulfides (3a) to (5a) in Example 16. Fig. 4 is a diagram showing the time course of CoS and CoS before use in Examples 2 and 3. ２ , cobalt-silicon composite oxide (CoO ｘ -SiO ｙ ), CoO after use in Example 6 ｘ -SiO ｙ , and α-Co before use in Example 9 ２ SiO ４ 5 shows the spectrum obtained by XRD measurement of CoO before use in Example 6. ｘ -SiO ｙ 6 is a diagram showing an element mapping image obtained by EDS measurement of CoO after use in Example 6. ｘ -SiO ｙ Figure 7 shows the structural formulas of compounds (1b) to (1s) used in Examples 18 to 35. Figure 8 shows the structural formulas of thiols (2b) to (2s) synthesized in Examples 18 to 35.

[0022] The method for producing a thiol according to an embodiment of the present invention involves reacting an alkene (1) or a derivative thereof with sulfur in the presence of hydrogen and a metal element to obtain a thiol (2). Figure 1 shows the reaction in the method for producing a thiol according to this embodiment. The reaction conditions shown in Figure 1, such as the catalyst type, reaction temperature, and heating time, are merely examples and may be changed as appropriate depending on the raw material type, etc.

[0023] (Alkene (1)) The (1) used in the above step is not particularly limited as long as it has a double bond at the terminal or a part thereof, and is, for example, an acyclic olefin (1A), a cyclic olefin (1B), or a derivative thereof. The acyclic olefin (1A) used in this embodiment is, for example, R １ R ２ C=CH ２ ...(A) (in the formula, R １ is an alkyl group, and R ２ is a hydrogen atom or an alkyl group, and R １ and R ２ The total number of carbon atoms in the alkene (1) is 2 to 20. From the viewpoint of industrial raw materials that utilize the properties of sulfur, among alkenes (1), R １ and R ２ Alkenes having a total of 2 to 18 carbon atoms are preferred, and R １ and R ２ More preferred is an alkene having a total of 2 to 16 carbon atoms. Examples of the acyclic olefin (1A) used in this embodiment include compounds (1a), (1b), and (1h) described below (see FIG. 9).

[0024] The acyclic olefin (1A) may also have other functional groups such as an aryl group, an alkoxy group, a hydroxy group, a cycloalkyl group, or a silylalkyl group. When the acyclic olefin (1A) has an aryl group, examples thereof include compounds (1f), (1i), and (1l) to (1r) described below (see FIG. 9). When the acyclic olefin (1A) further has an alkoxy group, examples thereof include compound (1s) described below. When the acyclic olefin (1A) further has a hydroxy group, examples thereof include compounds (1j) and (1k) described below. When the acyclic olefin (1A) further has a cycloalkyl group, examples thereof include compounds (1d) and (1e) described below. When the acyclic olefin (1A) further has a silylalkyl group, examples thereof include compound (1c) described below.

[0025] The cyclic olefin (1B) used in this embodiment is, for example, C ｎ H ２ｎ－２...(B) (wherein n≧3) Examples of the cyclic olefin (1B) include the compound (1g) described below.

[0026] In the production method of this embodiment, an alkene other than the alkene (1) can be used in combination with the alkene (1) within a range that does not impair the effects of the present invention. In other words, the raw material used in the production method of this embodiment may contain the alkene (1) and an alkene other than the alkene (1).

[0027] (Sulfur) The sulfur used in the present embodiment is not particularly limited, and may be in a solid state such as small lumps, flakes, or powder, or in a molten state (liquid). Among these, molten sulfur is preferred from the viewpoint of ease of charging in large-scale production.

[0028] In the above step, the ratio of alkene (1) to sulfur to be used is, from the viewpoint of solubility, 1.0 to 5.0 mol of S element per 1 mol of olefin (a) (1.0 to 5.0 molar equivalents of S equivalent, S ８ The amount is preferably 0.125 to 0.625 molar equivalents as S equivalents, and 1.0 to 4.0 mol (1.0 to 4.0 molar equivalents as S equivalents, ８ more preferably 0.125 to 0.5 molar equivalents as S equivalents), and more preferably 1.0 to 3.5 mol (1.0 to 3.5 molar equivalents as S equivalents, ８ More preferably, the molar equivalent is 0.125 to 0.438.

[0029] (Hydrogen) The hydrogen used in this embodiment is typically hydrogen gas. Hydrogen gas is widely distributed and is more readily available than hydrogen sulfide. Although hydrogen gas is flammable, it is non-toxic and odorless, making it easier to handle than hydrogen sulfide. The hydrogen gas is not particularly limited, but can be, for example, 99.99% or more, 99.999% or more, or 99.9999% or more.

[0030] The method for obtaining hydrogen gas is not particularly limited, and hydrogen gas available on the market may be obtained, or hydrogen gas may be produced using a reforming method in which hydrogen is obtained by reacting a hydrocarbon such as methane with water vapor, or an electrolysis method in which hydrogen is obtained by electrolyzing water.

[0031] When alkene (1) and sulfur are reacted in the presence of hydrogen, the pressure of the hydrogen supplied is preferably 0.1 MPa or more and 10.0 MPa or less, more preferably 1.0 MPa or more and 9.0 MPa or less, and even more preferably 2.0 MPa or more and 8.0 MPa or less. By adjusting the pressure of the hydrogen supplied to 0.1 MPa or more and 10.0 MPa or less, the yield of the obtained thiol (2) can be improved.

[0032] The heating temperature during the reaction of alkene (1) with sulfur in the presence of hydrogen is preferably 100° C. or higher and 200° C. or lower, more preferably 100° C. or higher and 160° C. or lower, more preferably 100° C. or higher and 140° C. or lower, and particularly preferably 120° C. or higher and 140° C. or lower. By setting the heating temperature during the reaction to 100° C. or higher and 200° C. or lower, the reaction time can be shortened to improve productivity, while also improving the yield of the resulting thiol (2).

[0033] In the above process, alkene (1) and sulfur are reacted in the presence of hydrogen to obtain thiol (2), but the reaction may also be carried out in the presence of hydrogen and a metal element. By using a metal element as a catalyst and catalytically reacting alkene (1) and sulfur in the presence of hydrogen, the yield of thiol (2) can be improved.

[0034] (Metal Element) The metal element used in this embodiment is preferably one or more metal elements selected from Groups 6 to 11. Examples of such metal elements include the following: Group 6: chromium (Cr), molybdenum (Mo), tungsten (W) Group 7: manganese (Mn), technetium (Tc), rhenium (Re) Group 8: iron (Fe), ruthenium (Ru), osmium (Os) Group 9: cobalt (Co), rhodium (Rh), iridium (Ir) Group 10: nickel (Ni), palladium (Pd), platinum (Pt) Group 11: copper (Cu), silver (Ag), gold (Au)

[0035] The metal element is preferably a metal element constituting, for example, a metal oxide, a metal sulfide, or a metal carbonate. When the metal element is a metal element constituting, for example, a metal oxide, the alkene (1) is reacted with sulfur in the presence of hydrogen and the metal oxide. When the metal element is a metal element constituting a metal sulfide, the alkene (1) is reacted with sulfur in the presence of hydrogen and the metal sulfide. The valence of the metal element constituting the metal oxide or metal sulfide is not particularly limited and can take various values ​​such as +1 or +2.

[0036] When the metal element is a metal element constituting a metal oxide, examples of the metal oxide include, but are not limited to, the following: Group 6 metal oxide: CrO ３ , MoO ３ , W.O. ３ Group 7 metal oxide: Mn ２ O ３ , Tc ２ O ７ , ReO ３ Group 8 metal oxide: Fe ２ O ３ , RuO ２ , OsO ４ Group 9 metal oxides: CoO, Rh ２ O ３ , IrO ２ Group 10 metal oxides: NiO, PdO, PtO ２ Group 11 metal oxides: CuO, Ag ２ O, Au ２ O ３

[0037] When the metal element is a metal element constituting a metal sulfide, examples of the metal sulfide include, but are not limited to, the following: Group 6 metal sulfide: Cr ２ S ３ , MoS ２ , W.S. ２ Group 7 metal sulfides: MnS, ReS ２ Group 8 metal sulfides: FeS, RuS ２ , OsS ２ Group 9 metal sulfides: CoS, Rh ２ S３ , IrS ２ Group 10 metal sulfide: Ni ３ S ２ , PdS, PtS Group 11 metal sulfides: CuS, Ag ２ S., Au. ２ S

[0038] When the metal element is, for example, cobalt (Co), cobalt oxide can be used as the metal oxide, and cobalt sulfide can be used as the metal sulfide. When cobalt oxide is used as the metal oxide, alkene (1) is reacted with sulfur in the presence of hydrogen and cobalt oxide. The cobalt oxide used is not particularly limited, and may be CoO, Co ２ O ３ , Co ３ O ４ When cobalt sulfide is used as the metal sulfide, the alkene (1) is reacted with sulfur in the presence of hydrogen and cobalt sulfide. The cobalt sulfide used is not particularly limited, and examples thereof include CoS, Co ９ S ８ , CoS ２ , Co ３ S ４ Among these, from the viewpoint of improving the yield of dialkyl polysulfide (A), cobalt oxide, particularly Co ３ O ４ is preferred.

[0039] When the metal element is a metal element constituting a metal oxide, the metal oxide may contain a plurality of metal elements selected from Groups 6 to 11. In this case, the metal oxide used may be, for example, NiCo. ２ O ４ In addition, when the metal element is a metal element constituting a metal oxide, the metal oxide may contain a metal element selected from Groups 6 to 11 and other elements. Examples of other elements include silicon (Si). In this case, examples of the metal oxide used include Co ２ SiO ４ , α-Co ２ SiO ４ CoO such as ｘ -SiOｙ Ya, Ni ２ SiO ４ NiO such as ｘ -SiO ｙ Examples include:

[0040] When the metal element is a metal element constituting a metal carbonate, the metal carbonate to be used is, for example, CoCO ３ Examples include:

[0041] The amount of the metal element added to the alkene (1) is preferably 0.1 mol % to 10 mol %, more preferably 1.0 mol % to 10 mol %, and even more preferably 2.0 mol % to 7.0 mol %. When the amount of the metal element added to the alkene (1) is 0.1 mol % to 10 mol %, the reaction of the alkene (1) with sulfur in the presence of hydrogen is promoted, and the yield of the obtained thiol (2) can be improved.

[0042] (Zeolite) In the production method of this embodiment, alkene (1) and sulfur are reacted in the presence of hydrogen and a metal element to obtain thiol (2). However, this is not limiting. alkene (1) and sulfur may also be reacted in the presence of hydrogen, the metal element, and a zeolite. By catalytically reacting alkene (1) and sulfur with a metal element and a zeolite in the presence of hydrogen, the yield of the obtained thiol (2) can be further improved. Zeolite is a crystalline aluminosilicate that has a skeletal structure in which silica and alumina are regularly linked, and contains cations as ion exchange sites within the pore structure. The pore structure defined by the zeolite skeletal structure is not particularly limited, and examples thereof include LTA (A-type), FER (ferrierite), MWW (MCM-22), MFI (ZSM-5), MOR (mordenite), LTL (L-type), FAU (Y-type, X-type), and BEA (beta-type). Among these, from the viewpoints of availability and economy, it is preferable that the zeolite has an X-type or A-type pore structure.

[0043] The zeolite is preferably basic. Examples of basic zeolites include zeolites containing cations of alkali metals or alkaline earth metals. Examples of alkali metals include sodium (Na) and potassium (K), and examples of alkaline earth metals include magnesium (Mg) and calcium (Ca).

[0044] From the viewpoint of improving the yield of thiol (2), the zeolite is preferably an Na-X type having an X-type skeletal structure and containing sodium ions, or an Na-A type having an A-type skeletal structure and containing sodium ions, and among these, the Na-A type is more preferred.

[0045] The amount of the zeolite added is preferably 2.0 parts by mass or more and 25 parts by mass or less, more preferably 2.0 parts by mass or more and 15 parts by mass or less, even more preferably 3.0 parts by mass or more and 10 parts by mass or less, and particularly preferably 5.0 parts by mass or more and 9.0 parts by mass or less, relative to 100 parts by mass of the alkene (1). When the amount of the zeolite added is 2.0 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the alkene (1), the yield at the first reuse can be maintained at a high value.

[0046] Thiol (2) is obtained by the production method of this embodiment. In this case, this production method may also obtain thiol (2) and one or more other compounds other than thiol (2). Examples of other compounds include dialkyl monosulfides. The contents (yields) of thiol (2) and dialkyl monosulfides having different numbers of carbon atoms can be determined from the peak areas in a chart obtained by gas chromatography (hereinafter also referred to as "GC") measurement.

[0047] The production method of this embodiment allows for efficient production of thiol (2), which can be suitably used as, for example, a gas odorant, a fragrance, or a ligand.

[0048] Examples of the present invention will be described below, but the present invention is not limited to the examples shown below.

[0049] (Example 1) A stirrer and compound (1a) (H ２ C=C-C １２ H ２５ ) 6 mmol, sulfur (S ８ ) 0.4125 molar equivalents (3.3 molar equivalents as S element), Co ３ O ４ After charging 6 mol% of Sigma-Aldrich nanopowder (50 nm or less (TEM)) and 100 mg of zeolite (Sigma-Aldrich molecular sieve 4A, Na-A type), hydrogen was added under pressure to 7.0 MPa. While stirring at 800 rpm with a magnetic stirrer, the autoclave was heated to 130°C and the reaction was carried out at the same temperature for 16 hours. After cooling to room temperature and opening the pressure valve, 20 mg of tridecane (1.7 parts by mass per 100 parts by mass of compound (1a)) was added as an internal standard to the reaction solution. Air was then blown in to distill off any remaining hydrogen sulfide. After removing unreacted sulfur and the catalyst using a centrifuge, thiol (2a) was obtained. The reaction in the production method of thiol (2a) in Example 1 is shown in Figure 2.

[0050] (Example 2) The type of metal catalyst was Co ３ O ４ Thiol (2) was obtained in the same manner as in Example 1, except that the thiol (2) was changed to CoS (manufactured by Strem Chemicals).

[0051] (Example 3) The type of metal catalyst was Co ３ O ４ From CoS ２ Thiol (2a) was obtained in the same manner as in Example 1, except that the thiol used was changed to thiol (manufactured by Alfa Aesar).

[0052] (Example 4) The type of metal catalyst was Co ３ O ４ Nickel-cobalt composite oxide (NiO ｘ -CoO ｙThiol (2a) was obtained in the same manner as in Example 1, except that the thiol (2b) was changed to thiol (2c). Nickel-cobalt composite oxide was prepared by the following method. Nickel acetate tetrahydrate (Kishida Chemical Co., Ltd., 2.48 g, 10 mmol) and cobalt nitrate nonahydrate (Fujifilm Wako Pure Chemical Industries, Ltd., 5.82 g, 20 mmol) were dissolved in 150 mL of distilled water, and a solution of ammonium carbonate (Fujifilm Wako Pure Chemical Industries, Ltd., 2.88 g, 30 mmol) dissolved in 50 mL of distilled water was added dropwise over 5 minutes at room temperature while stirring. The mixture was then left at room temperature for 3 hours. After the reaction was completed, the resulting precipitate was filtered, washed with 2 x 50 mL of distilled water, and dried at 70°C in air for 15 hours to obtain a black solid. The resulting mixture was then crushed in a mortar and mortar, and the black powder was recovered by sieving to a size of 125 μm or less. The resulting mixture was then transferred to a baking dish and baked. The firing conditions were as follows: the temperature was raised to 300°C in 1 hour (heating program: 5°C / min) and then maintained at that temperature for 6 hours. After firing, the material was cooled to room temperature, and the black powder (2.16 g) was recovered. The cobalt and nickel contents were evaluated using a microwave plasma atomic emission spectrometer (MP-AES), and the cobalt content was 38% by mass and the nickel content was 11% by mass.

[0053] (Example 5) The type of metal catalyst was Co ３ O ４ Thiol (2a) was obtained in the same manner as in Example 1, except that the catalyst used was changed to NiO (manufactured by Sigma-Aldrich).

[0054] (Example 6) The type of metal catalyst was Co ３ O ４ Cobalt-silicon composite oxide (CoO ｘ -SiO ｙ) was changed to thiol (2a). The cobalt-silicon composite oxide was prepared in the same manner as in Example 1. Cobalt nitrate hexahydrate (Fujifilm Wako Pure Chemical Industries, Ltd., 2.91 g, 10 mmol) was dissolved in 90 mL of distilled water, and a solution of sodium silicate (Sigma-Aldrich, 1.22 g, 10 mmol) dissolved in 10 mL of distilled water was added dropwise over 3 minutes while stirring at room temperature, and the mixture was allowed to stand at room temperature for 3 hours. After completion of the reaction, the resulting precipitate was filtered, washed twice with 50 mL of distilled water, and dried at 70°C in air for 14 hours to obtain a purple solid. The resulting mixture was then crushed in a mortar and mortar, and a pink powder (1.6 g) was recovered after being sieved to a size of 125 μm or less. The cobalt content was evaluated by MP-AES, and found to be 30% by mass.

[0055] (Example 7) The type of metal catalyst was Co ３ O ４ From CoCO ３ Thiol (2a) was obtained in the same manner as in Example 1, except that the thiol (2b) was changed to thiol (2c) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0056] (Example 8) The type of metal catalyst was Co ３ O ４ Nickel-silicon composite oxide (NiO ｘ -SiO ｙ Thiol (2a) was obtained in the same manner as in Example 1, except that NiO ｘ -SiO ｙ was prepared by the following method. Nickel acetate tetrahydrate (Kishida Chemical Co., Ltd., 4.98 g, 20 mmol) was dissolved in 90 mL of distilled water, and a solution of sodium silicate (Sigma-Aldrich Co., Ltd., 2.44 g, 20 mmol) dissolved in 10 mL of distilled water was added dropwise over 3 minutes while stirring at room temperature, and the mixture was left at room temperature for 3 hours. After the reaction was completed, the resulting precipitate was filtered, washed with 2 x 50 mL of distilled water, and dried at 70 °C in air for 14 hours to obtain a purple solid. The solid was then crushed in a mortar and mortar, and a green powder (3.97 g) was recovered by sieving to a size of 125 μm or less. The nickel content was evaluated by MP-AES, and the nickel content was found to be 29% by mass.

[0057] (Example 9) The type of metal catalyst was Co ３ O ４ From α-Co ２ SiO ４ Thiol (2a) was obtained in the same manner as in Example 1, except that α-Co ２ SiO ４ was prepared by the following method. ｘ -SiO ｙ The mixture (1.1 g) was transferred to a quartz or alumina board and placed in a vacuum furnace equipped with a hydrogen generator. The atmosphere was purged with hydrogen three times and then heated to 1000°C in a hydrogen atmosphere over 3 hours and 18 minutes (heating program: 5°C / min). The temperature was then maintained for 3 hours under a hydrogen atmosphere. After sintering, the mixture was cooled to room temperature, and a purple powder (1 g) was recovered. The cobalt content was evaluated by MP-AES and found to be 25% by mass.

[0058] The thiols (2) obtained in Examples 1 to 9 were measured and evaluated by the following methods.

[0059] [Measurement of Thiol Yield] The yields of thiol (2a) and dialkyl monosulfides (3a) to (5a) were determined from the peak areas of the thiol (2) and dialkyl monosulfides (3a) to (5a) obtained under the following measurement conditions using a gas chromatograph (Agilent Technologies, 6850 Series II) and a column (Agilent Technologies, HP-1, 30 m, diameter 0.32 mm, film thickness 0.25 μm). The conversion rate was determined from the yield of compound (1a). The measurement and evaluation results for Examples 1 to 9 are shown in Table 1.

[0060] [GC measurement conditions] (Temperature program) 1. 40°C, hold for 5 min 2. Heat to 240°C at 10°C / min 3. Hold for 15 min after reaching 240°C (GC settings) Gases used: nitrogen (carrier gas), hydrogen (for detector), air (for detector) Injection port settings: heater 200°C, pressure 93 kPa, total flow (N ２ ) 24.5 mL / min, split ratio 5.3:1. Column settings: pressure 93 kPa, flow rate (N ２) 3.6 mL / min, average linear velocity 52 cm / sec Detector settings: heater 250°C, hydrogen flow rate 30.0 mL / min, air flow rate 250.0 mL / min, makeup flow rate (N ２ ) 10.0 mL / min (GC retention times of standards used to identify each compound) Internal standard (tridecane): 13.5 min Tetradecene: 14.9 min Thiol: 18.8 min Dialkylmonosulfanes (3a: 38.7 min, 4a: 36.0 min, 5a: 34.8 min)

[0061]

[0062] From the results in Table 1, in all of Examples 1 to 9, the compound (1a) as the alkene (1) and powdered sulfur were reacted with hydrogen, Co ３ O ４、 CoS, CoS ２ ,NiCo ２ O ４ , NiO, Co ２ SiO ４ , CoCO ３ , Ni ２ SiO ４ and Co ２ SiO ４ In particular, in Examples 5 to 7, the compound (1a) was reacted with sulfur in the presence of hydrogen, NiO, Co, and zeolite to obtain the thiol (2a) in a yield of 3 to 63%. ２ SiO ４ and CoCO ３ and zeolite, the total yield of thiol (2a) exceeded 50%. In addition, in all of Examples 1 to 9, the ratio of the yield of thiol (2a) to the total yield of thiol (2a) and dialkyl monosulfides (3a) to (5a) exceeded 20%.

[0063] (Example 10) Powdered sulfur (S ８ Thiol (2a) was obtained in the same manner as in Example 6, except that the amount of sulfur element was changed from 3.3 molar equivalents to 1.7 molar equivalents.

[0064] Example 11 Thiol (2a) was obtained in the same manner as in Example 6, except that zeolite was not used.

[0065] Example 12 Thiol (2a) was obtained in the same manner as in Example 6, except that zeolite was not used and the hydrogen pressure during charging was changed from 7.0 MPa to 5.0 MPa.

[0066] Example 13 Thiol (2a) was obtained in the same manner as in Example 6, except that zeolite was not used and the hydrogen pressure during charging was changed from 7.0 MPa to 3.0 MPa.

[0067] Example 14 Thiol (2a) was obtained in the same manner as in Example 6, except that zeolite was not used and the heating temperature of the autoclave, ie, the reaction temperature, was changed from 130°C to 120°C.

[0068] Example 15 Thiol (2a) was obtained in the same manner as in Example 6, except that zeolite was not used and the heating temperature of the autoclave, ie, the reaction temperature, was changed from 130°C to 140°C.

[0069] Comparative Example 1 Thiol (2a) was obtained in the same manner as in Example 6, except that no catalyst was used. The measurement and evaluation results of Examples 10 to 15 and Comparative Example 1 are shown in Table 2.

[0070]

[0071] From the results in Table 2, in Example 10, powdered sulfur (S ８It was found that even when the amount of sulfur element (2a) was changed from 3.3 molar equivalents to 1.7 molar equivalents, thiol (2a) could be obtained in a yield of 27%. In Example 11, it was found that even when no zeolite was used, thiol (2a) could be obtained in a yield of 64%, similar to Example 1. Furthermore, in Examples 12 and 13, it was found that even when no zeolite was used and the hydrogen pressure during charging was changed from 7.0 MPa to 5.0 MPa or 3.0 MPa, thiol (2a) could be obtained in a yield of 54% or 18%. Furthermore, in Examples 14 and 15, it was found that even when no zeolite was used and the reaction temperature was changed from 130°C to 120°C or 140°C, thiol (2a) could be obtained in a yield of 55% or 62%.

[0072] On the other hand, in Comparative Example 1, when no catalyst was used, the conversion rate was 92%, which was not particularly low, but the yield of thiol (2a) was low at 2%, and the ratio of the yield of thiol (2a) to the total yield of thiol (2a) and dialkyl monosulfides (3a) to (5a) was low at 18.1%.

[0073] (Example 16) A stirrer and compound (1a) (H ２ C=C-C １２ H ２５ ) 6 mmol, powdered sulfur (S ８ ) 0.4125 molar equivalents (3.3 molar equivalents as S element), CoO ｘ -SiO ｙ After charging 6.6 mol%, hydrogen was charged under pressure up to 7.0 MPa. While stirring at 800 rpm with a magnetic stirrer, the autoclave was heated to 130°C and the reaction was carried out at the same temperature for a predetermined time (t). After that, it was cooled to room temperature and the pressure valve was opened. Then, 20 mg of tridecane (1.7 parts by mass relative to 100 parts by mass of compound (1a)) was added as an internal standard to the reaction solution, and air was blown in to distill off the remaining hydrogen sulfide. Unreacted sulfur and Co ３ O ４ After removing the residue by centrifugation, thiol (2a) was obtained. The time course of the yield of thiol (2a) and the total yield of dialkyl monosulfides (3a) to (5a) in Example 16 is shown in FIG.

[0074] As shown in Figure 3, it was found that the compound (1a) reacted almost completely after about 3 hours, and the conversion rate reached its highest value after about 6 hours. It was found that the reduction reaction of thiol (2a) began after about 6 hours, and the yield of thiol (2a) reached its highest value after about 9 hours. It was found that the yields of dialkyl monosulfides (3a) to (5a) remained almost unchanged after about 3 hours.

[0075] (Evaluation of catalyst characteristics) CoS and CoS before use in Examples 2 and 3 ２ , CoO before use in Example 6 ｘ -SiO ｙ , CoO after use in Example 6 ｘ -SiO ｙ , and α-Co before use in Example 9 ２ SiO ４ The sample was subjected to XRD measurement using an X-ray diffractometer (manufactured by Rigaku Corporation, device name "MiniFlex600") under the following conditions. The results are shown in FIG. 4.

[0076] [XRD measurement conditions] Cu Kα radiation source used (λ = 0.15418 nm) Measurement speed: 1.5° / min

[0077] As shown in FIG. 4, in Example 6, CoO ｘ -SiO ｙ When used as a catalyst in the synthesis reaction of thiol (2a), its crystal structure is similar to that of Co used in Examples 2 and 3. ｘ S ｙ The crystal structure of the α-Co alloy used in Example 9 was changed to one close to that of the α-Co alloy used in Example 9. ２ SiO ４ It was confirmed that the crystal structure is different from that of

[0078] Next, CoO before use in Example 6 ｘ -SiO ｙ , and CoO after use in Example 6 ｘ -SiO ｙ The sample was subjected to elemental analysis using an energy dispersive X-ray analyzer (EDS) (manufactured by JEOL, device name "JEM-ARM200F"). The EDS measurement was carried out under the following conditions. The results are shown in FIGS. 5 and 6.

[0079] [EDS measurement conditions] Room temperature, high vacuum conditions Data acquisition time: 20 mmsec Resolution: 128 x 128

[0080] As shown in FIG. 5, the CoO ｘ -SiO ｙ It was confirmed that cobalt (Co), silica (Si), and oxygen (O) were distributed almost uniformly throughout the catalyst. ｘ -SiO ｙ It was confirmed that sulfur (S) was distributed almost uniformly throughout the catalyst, while the distributions of cobalt (Co), silica (Si) and oxygen (O) were maintained.

[0081] In addition, CoO after use in Example 6 ｘ -SiO ｙ A number of samples were prepared for each of the above, and the organic matter was oxidized using sulfuric acid and aqua regia, followed by extraction of cobalt (Co) in an aqueous solution. The cobalt content in the resulting aqueous solution was measured, and the cobalt content was found to be less than 0.09 ppm in all samples. ｘ -SiO ｙ The cobalt (Co) contained in the catalyst was hardly eluted during the synthesis reaction, and it was confirmed that the production method of this invention can maintain the catalytic activity that the catalyst originally possesses.

[0082] (Examples 18 to 35) Compound (1a) (H ２ C=C-C １２ H ２５ Thiols (2b) to (2s) shown in FIG. 8 were synthesized in the same manner as in Example 6, except that the compound (1b) to (1s) shown in FIG. 7 was used instead. The yields of the obtained thiols (2b) to (2s) are shown in FIG. 8. As shown in FIG. 8, in all of Examples 18 to 35, any of compounds (1b) to (1s) and powdered sulfur were reacted with hydrogen, CoO ｘ -SiO ｙ It was found that the thiols (2b) to (2s) could be obtained in yields of 36 to 94% by reacting them in the presence of methyl methyl ester and zeolite.

[0083] The above-mentioned method for producing thiol does not require hydrogen sulfide gas, which is difficult to handle, or an expensive organic base, and does not require the installation of an ultraviolet irradiation device, platinum electrodes, or the like. Thiol can be obtained using hydrogen gas, which is relatively easy to obtain and handle, and a catalyst, making it extremely useful as it allows thiol to be easily produced in various regions.

Claims

1. A method for producing a thiol, comprising reacting an alkene (1) or a derivative thereof with sulfur in the presence of hydrogen and a metal element to obtain a thiol (2), The method for producing a thiol, wherein the alkene (1) is represented by R 1 R 2 C═CH 2 ...(A) (wherein R 1 is an alkyl group, R 2 is a hydrogen atom or an alkyl group, and the total number of carbon atoms in R 1 and R 2 is 2 to 20).

2. The method for producing a thiol according to claim 1, wherein when the alkene (1) or a derivative thereof is reacted with sulfur, the pressure of hydrogen supplied is 0.1 MPa or more and 10 MPa or less.

3. The method for producing a thiol according to claim 1 or 2, wherein the heating temperature when reacting the alkene (1) or a derivative thereof with sulfur in the presence of hydrogen is 100° C. or higher and 200° C. or lower.

4. The method for producing a thiol according to claim 1, wherein the metal element is one or more metal elements selected from groups 6 to 11.

5. The method for producing a thiol according to claim 4 , wherein the metal element is a metal element that constitutes a metal oxide or a metal sulfide.

6. The method for producing a thiol according to claim 1, wherein the amount of the metal element added to the alkene (1) or a derivative thereof is 0.1 mol % or more and 10 mol % or less.

7. The method for producing a thiol according to claim 1, wherein the alkene (1) or a derivative thereof is reacted with sulfur in the presence of hydrogen, the metal element, and a zeolite.

8. The method for producing a thiol according to claim 7 , wherein the zeolite is basic.

9. The method for producing a thiol according to claim 8 , wherein the zeolite has an X-type or A-type pore structure.

10. The method for producing a thiol according to claim 7, wherein the amount of the zeolite added is 2.0 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the alkene (1).

11. R in the above general formula (A) １ and R ２ The method for producing a thiol according to claim 1, wherein the total number of carbon atoms is 2 to 16.