Method for producing thiol

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

Technical Field

[0001] The present invention relates to a method for producing thiols. This application claims priority based on Japanese Patent Application No. 2023-034877 filed in Japan on March 7, 2023, and incorporates the content herein by reference.

Background Art

[0002] Thiols are used in various applications such 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, as methods for producing thiols, for example, (1) a synthesis method using a substitution reaction (SN2 reaction) in which reactants interact in one step (Non-Patent Document 1), (2) a synthesis method of thiols using hydrogen sulfide with alcohol as a raw material (Non-Patent Document 2), (3) a synthesis method of thiols using hydrogen sulfide with alkene as a raw material (Non-Patent Document 3), (4) a synthesis method of thiols using alkene as a raw material with ultraviolet light or a platinum electrode (Non-Patent Document 4), (5) a synthesis method of thiols using sulfur and a carbonyl compound (Non-Patent Document 5), and the like.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the synthesis method of (1) above, the atom efficiency is low, and a large amount of waste is by-produced. In the synthesis method of (2) above, the reaction conditions such as a high reaction temperature are severe, and production is difficult. In the synthesis method of (3) above, the use of hydrogen sulfide is essential, and since hydrogen sulfide is highly toxic, handling is complicated in terms of equipment management and the like. Further, in the synthesis method of (4) above, an ultraviolet irradiation device and an expensive platinum electrode are required, leading to an increase in production cost. In the synthesis method of (5) above, it is necessary to use CO gas and an expensive organic base, and like the synthesis methods of (3) and (4) above, it causes complexity in handling raw materials and an increase in production cost.

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

Means for Solving the Problems

[0007] As a result of intensive studies to achieve the above object, the present inventor has found that various thiols can be easily obtained by reacting sulfur and hydrogen with a carbon atom at the 2-position of an alkene having a double bond at the terminal or a part thereof in the presence of a catalyst having a metal element. In particular, by using hydrogen (gas), which has a higher supply potential 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 an expensive organic base, and without using an ultraviolet irradiation device, a platinum electrode, or the like.

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

[0009] [2] When reacting the alkene (1) or its derivative with sulfur, the production method of the thiol according to [1] above, wherein the pressure of the supplied hydrogen is 0.1 MPa or more and 10 MPa or less.

[0010] [3] When reacting the alkene (1) or its derivative with sulfur in the presence of hydrogen, the production method of the thiol according to [1] or [2] above, wherein the heating temperature is 100 °C or more and 200 °C or less.

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

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

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

[0014] [7] The production method of the thiol according to any one of [1] to [6] above, wherein the alkene (1) or its derivative and sulfur are reacted in the presence of hydrogen, the metal element and zeolite.

[0015] [8] The production method of the thiol according to [7] above, wherein the zeolite has basicity.

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

[0017]

[10] The production method of the thiol according to any one of [7] to [9] above, wherein the addition amount of the zeolite 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).

[0018]

[11] The alkene (1) is R 1 R 2 C=CH2 ··· (A) (wherein R 1 is an alkyl group, R 2 is a hydrogen atom or an alkyl group, and R 1 and R 2 have a total carbon atom number of 2 to 20.) The method for producing a thiol according to any one of [1] to

[10] above.

[0019]

[12] In the general formula (A), the total carbon atom number of R 1 and R 2 is 2 to 16. The method for producing a thiol according to

[11] above. [Advantages of the Invention]

[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, is easy to handle raw materials, and can further reduce production costs. [Brief Description of the Drawings]

[0021]

Figure 1

Figure 2

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Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Mode for Carrying Out the Invention

[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). FIG. 1 shows the reaction in the method for producing a thiol according to this embodiment. Note that the reaction conditions such as the catalyst species, reaction temperature, and heating time shown in FIG. 1 are examples and can be appropriately changed according to the raw material species and the like.

[0023] (Alkene (1)) (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=CH2 ··· (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 of R 1 and R 2 is 2 to 20.) From the viewpoint of industrial raw materials that utilize the properties of sulfur, among the alkenes (1), alkenes in which the total number of carbon atoms of R 1 and R 2 is 2 to 18 are preferable, and R 1 and R 2Alkenes with a total carbon atom number of 2 to 16 are more preferred. Examples of the acyclic olefin (1A) used in this embodiment include compounds (1a), (1b), (1h), etc. described later (see Fig. 9).

[0024] In addition, the acyclic olefin (1A) may have other functional groups such as an aryl group, an alkoxy group, a hydroxy group, a cycloalkyl group, a silylalkyl group, etc. When the acyclic olefin (1A) has an aryl group, for example, compounds (1f), (1i), (1l) to (1r), etc. described later can be mentioned (see Fig. 9). When the acyclic olefin (1A) further has an alkoxy group, for example, compound (1s) described later can be mentioned. When the acyclic olefin (1A) further has a hydroxy group, for example, compounds (1j), (1k), etc. described later can be mentioned. When the acyclic olefin (1A) further has a cycloalkyl group, for example, compounds (1d), (1e), etc. can be mentioned. When the acyclic olefin (1A) further has a silylalkyl group, for example, compound (1c) described later can be mentioned.

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

[0026] In the production method of this embodiment, other alkenes other than alkene (1) can be used in combination with alkene (1) as long as the effects of the present invention are not impaired. That is, the raw material used in the production method of this embodiment may contain alkene (1) and other alkenes other than alkene (1).

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

[0028] In the above process, from the perspective of solubility, the usage ratio of alkene (1) to sulfur is preferably 1.0 to 5.0 mol of S element per 1 mol of olefin (a) (1.0 to 5.0 molar equivalents in terms of S equivalent, 0.125 to 0.625 molar equivalents in terms of S8), more preferably 1.0 to 4.0 mol (1.0 to 4.0 molar equivalents in terms of S equivalent, 0.125 to 0.5 molar equivalents in terms of S8), and even more preferably 1.0 to 3.5 mol (1.0 to 3.5 molar equivalents in terms of S equivalent, 0.125 to 0.438 molar equivalents in terms of S8).

[0029] (Hydrogen) The hydrogen used in this embodiment is typically hydrogen gas. Hydrogen gas has a large flow rate and is more easily available compared to hydrogen sulfide. Also, although hydrogen gas is flammable, it is non-toxic and odorless, so it is easier to handle compared to hydrogen sulfide. Hydrogen gas is not particularly limited, but for example, it can be 99.99% or more, 99.999% or more, or 99.9999% or more.

[0030] The method for obtaining hydrogen gas is not particularly limited. Hydrogen gas currently on the market may be obtained, or a reforming method of reacting hydrocarbons such as methane with steam to obtain hydrogen, or an electrolysis method of electrolyzing water to obtain hydrogen may be used to produce hydrogen gas.

[0031] When reacting alkene (1) with sulfur in the presence of hydrogen, the pressure of the supplied hydrogen 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 setting the pressure of the supplied hydrogen to 0.1 MPa or more and 10.0 MPa or less, the yield of the resulting thiol (2) can be improved.

[0032] When reacting alkene (1) with sulfur in the presence of hydrogen, the heating temperature is preferably 100°C or higher and 200°C or lower, more preferably 100°C or higher and 160°C or lower, still 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, and the yield of the resulting thiol (2) can be improved.

[0033] In the above process, alkene (1) and sulfur are reacted in the presence of hydrogen to obtain thiol (2), but it is not limited thereto, and alkene (1) and sulfur may be reacted in the presence of hydrogen and a metal element. By using a metal element as a catalyst and causing alkene (1) and sulfur to undergo a catalytic reaction in the presence of hydrogen, the yield of the resulting 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 above metal element is preferably a metal element constituting, for example, a metal oxide, a metal sulfide or a metal carbonate. When the above metal element is a metal element constituting a metal oxide, for example, alkene (1) and sulfur are reacted in the presence of hydrogen and the above metal oxide. When the above metal element is a metal element constituting a metal sulfide, alkene (1) and sulfur are reacted in the presence of hydrogen and the above metal sulfide. The valence of the metal element constituting the metal oxide or the metal sulfide is not particularly limited and can take various values such as +1 and +2.

[0036] When the above 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 oxides: CrO3, MoO3, WO3 Group 7 metal oxides: Mn2O3, Tc2O7, ReO3 Group 8 metal oxides: Fe2O3, RuO2, OsO4 Group 9 metal oxides: CoO, Rh2O3, IrO2 Group 10 metal oxides: NiO, PdO, PtO2 Group 11 metal oxides: CuO, Ag2O, Au2O3

[0037] When the above 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 sulfides: Cr2S3, MoS2, WS2 Group 7 metal sulfides: MnS, ReS2 Group 8 metal sulfides: FeS, RuS2, OsS2 Group 9 metal sulfides: CoS, Rh2S3, IrS2 Group 10 metal sulfides: Ni3S2, PdS, PtS Group 11 metal sulfides: CuS, Ag2S, Au2S

[0038] When the above 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 using cobalt oxide as the metal oxide, alkene (1) and sulfur are reacted in the presence of hydrogen and cobalt oxide. The cobalt oxide used is not particularly limited, and examples include CoO, Co2O3, Co3O4, etc. When using cobalt sulfide as the metal sulfide, alkene (1) and sulfur are reacted in the presence of hydrogen and cobalt sulfide. The cobalt sulfide used is not particularly limited, and examples include CoS, Co9S8, CoS2, Co3S4, etc. Among these, from the viewpoint of improving the yield of dialkyl polysulfide (A), cobalt oxide, particularly Co3O4, is preferred.

[0039] When the above metal element is a metal element constituting the metal oxide, the metal oxide may have a plurality of metal elements selected from Group 6 to Group 11. In this case, examples of the metal oxide used include NiCo2O4, etc. Also, when the above metal element is a metal element constituting the metal oxide, the metal oxide may have a metal element selected from Group 6 to Group 11 and other elements. Examples of the other elements include silicon (Si). In this case, examples of the metal oxide used include CoO such as Co2SiO4, α-Co2SiO4 x -SiO y and NiO such as Ni2SiO4 x -SiO y can be mentioned.

[0040] When the above metal element is a metal element constituting the metal carbonate, examples of the metal carbonate used include CoCO3, etc.

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

[0042] (Zeolite) In the production method of the present embodiment, the alkene (1) and sulfur are reacted in the presence of hydrogen and a metal element to obtain the thiol (2). However, the present invention is not limited thereto, and the alkene (1) and sulfur may be reacted in the presence of hydrogen, the metal element, and zeolite. By using the metal element and zeolite as catalysts and causing the alkene (1) and sulfur to undergo a catalytic reaction by these two catalysts in the presence of hydrogen, the yield of the resulting thiol (2) can be further improved. Zeolite is a crystalline aluminosilicate, has a framework structure in which silica and alumina are regularly connected, and contains cations as ion exchange sites in the pore structure. The pore structure defined by the framework structure of zeolite is not particularly limited, and examples include LTA (type A), FER (ferrierite), MWW (MCM-22), MFI (ZSM-5), MOR (mordenite), LTL (type L), FAU (type Y, type X), BEA (beta type), and the like. Among these, from the viewpoints of easy availability and economy, it is preferable that the zeolite has an X-type or A-type pore structure.

[0043] The above zeolite preferably has basicity. Examples of the zeolite having basicity include zeolites containing cations of alkali metals or alkaline earth metals. Examples of the alkali metal include sodium (Na) and potassium (K), and examples of the alkaline earth metal include magnesium (Mg) and calcium (Ca).

[0044] From the perspective of improving the yield of thiol (2), the zeolite is preferably of the X-type framework structure and is Na-X type containing sodium ions, or of the A-type framework structure and is Na-A type containing sodium ions. Among these, Na-A type is more preferable.

[0045] The addition amount of the above zeolite 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, still 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 with respect to 100 parts by mass of alkene (1). When the addition amount of the above zeolite is 2.0 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of 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. At this time, in this production method, thiol (2) and one or more other compounds other than thiol (2) may be obtained. Examples of other compounds include dialkyl monosulfide. The content rate (yield) of each of thiol (2) and dialkyl monosulfide having different numbers of carbon atoms can be determined by the peak area of the chart obtained by gas chromatograph (hereinafter also referred to as "GC") measurement.

[0047] Thiol (2) can be efficiently obtained by the production method of this embodiment. Further, the obtained thiol (2) can be suitably used, for example, as a gas odorant, a fragrance or a ligand.

Examples

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

[0049] (Example 1) A stirrer, compound (1a) (H2C=C-C 12 H 25)6 mmol, 0.4125 molar equivalents of sulfur (S8) (3.3 molar equivalents as S element), 6 mol% of Co3O4 (manufactured by Sigma-Aldrich, nanopowder: 50 nm or less (TEM)), 100 mg of zeolite (manufactured by Sigma-Aldrich, molecular sieve 4A, Na-A type) were charged, and then hydrogen was pressurized to 7.0 MPa. While stirring at 800 rpm with a magnetic stirrer, the autoclave was heated to 130 °C and reacted at the same temperature for 16 hours. Then, after cooling to room temperature and opening the pressure valve, 20 mg of tridecane (1.7 parts by mass with respect to 100 parts by mass of compound (1a)) was added to the reaction solution as an internal standard substance, and further, air was blown in to distill off the remaining hydrogen sulfide. After removing unreacted sulfur and the catalyst by a centrifuge, thiol (2a) was obtained. The reaction in the method for producing thiol (2a) of Example 1 is shown in Figure 2.

[0050] (Example 2) Thiol (2) was obtained in the same manner as in Example 1 except that the type of metal catalyst was changed from Co3O4 to CoS (manufactured by Strem Chemicals).

[0051] (Example 3) Thiol (2a) was obtained in the same manner as in Example 1 except that the type of metal catalyst was changed from Co3O4 to CoS2 (manufactured by Alfa Aesar).

[0052] (Example 4) Thiol (2a) was obtained in the same manner as in Example 1 except that the type of metal catalyst was changed from Co3O4 to nickel-cobalt composite oxide (NiO x -CoO y ). The nickel-cobalt composite oxide was prepared by the following method. Nickel acetate tetrahydrate (manufactured by Kishida Chemical Co., 2.48 g, 10 mmol) and cobalt nitrate nonahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 5.82 g, 20 mmol) were dissolved in 150 mL of distilled water. While stirring a solution prepared by dissolving ammonium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 2.88 g, 30 mmol) in 50 mL of distilled water at room temperature, it was added dropwise over 5 minutes and left at room temperature for 3 hours as it was. After completion of the reaction, the obtained precipitate was separated by filtration, washed with 2×50 mL of distilled water, and dried in air at 70 °C for 15 hours to obtain a black solid. Then, it was pulverized in a mortar and a black powder with a particle size of 125 μm or less was collected through a sieve. Then, it was transferred to a firing dish and fired. The firing conditions were as follows: heating to 300 °C at 5 °C / min for 1 hour and holding at the same temperature for 6 hours. After firing, it was cooled to room temperature and a black powder was collected (2.16 g). When the cobalt and nickel contents were evaluated using a microwave plasma atomic emission spectrometer (MP-AES), the cobalt content was 38% by mass and the nickel content was 11% by mass.

[0053] (Example 5) Thiol (2a) was obtained in the same manner as in Example 1 except that the type of metal catalyst was changed from Co3O4 to NiO (manufactured by Sigma-Aldrich).

[0054] (Example 6) Thiol (2a) was obtained in the same manner as in Example 1 except that the type of metal catalyst was changed from Co3O4 to cobalt-silicon composite oxide (CoO x -SiO y ). The cobalt-silicon composite oxide was prepared by the following method. Cobalt(II) nitrate hexahydrate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., 2.91 g, 10 mmol) was dissolved in 90 mL of distilled water, and while stirring a solution prepared by dissolving sodium silicate (manufactured by Sigma-Aldrich, 1.22 g, 10 mmol) in 10 mL of distilled water at room temperature, it was added dropwise over 3 minutes and left to stand at room temperature for 3 hours as it was. After completion of the reaction, the obtained precipitate was separated by filtration and washed twice with 50 mL of distilled water, and dried in air at 70 °C for 14 hours to obtain a purple solid. Thereafter, it was pulverized in a mortar and a pink powder (1.6 g) made finer than 125 μm by a sieve was recovered. When the cobalt content was evaluated by MP-AES, the cobalt content was 30% by mass.

[0055] (Example 7) Thiol (2a) was obtained in the same manner as in Example 1 except that the type of metal catalyst was changed from Co3O4 to CoCO3 (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.).

[0056] (Example 8) Thiol (2a) was obtained in the same manner as in Example 1 except that the type of metal catalyst was changed from Co3O4 to nickel-silicon composite oxide (NiO x -SiO y ). NiO x -SiO y was prepared by the following method. Nickel(II) acetate tetrahydrate (manufactured by Kishida Chemical Co., Ltd., 4.98 g, 20 mmol) was dissolved in 90 mL of distilled water, and while stirring a solution prepared by dissolving sodium silicate (manufactured by Sigma-Aldrich, 2.44 g, 20 mmol) in 10 mL of distilled water at room temperature, it was added dropwise over 3 minutes and left to stand at room temperature for 3 hours as it was. After completion of the reaction, the obtained precipitate was separated by filtration and washed with 2 × 50 mL of distilled water, and dried in air at 70 °C for 14 hours to obtain a purple solid. Thereafter, it was pulverized in a mortar and a green powder (3.97 g) made finer than 125 μm by a sieve was recovered. When the nickel content was evaluated by MP-AES, the nickel content was 29% by mass.

[0057] (Example 9) Thiol (2a) was obtained in the same manner as in Example 1, except that the type of metal catalyst was changed from Co3O4 to α-Co2SiO4. α-Co2SiO4 was prepared by the following method. CoO x -SiO y (1.1 g) was transferred to a quartz or alumina board, loaded into a vacuum firing furnace equipped with a hydrogen generator, subjected to hydrogen substitution three times, and heated to 1000 °C in 3 hours and 18 minutes (heating program: 5 °C / min) under a hydrogen atmosphere. Then, it was held at the same temperature for 3 hours under a hydrogen atmosphere. After firing, it was cooled to room temperature, and a purple powder was recovered (1 g). When the cobalt content was evaluated by MP-AES, the cobalt content was 25% by mass.

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

[0059] [Measurement of Thiol Yield] The yields of thiol (2a) and dialkyl monosulfides (3a) to (5a) were determined from the peak areas by obtaining the chromatograms of thiol (2) and dialkyl monosulfides (3a) to (5a) 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 of Examples 1 to 9 are shown in Table 1.

[0060] [GC Measurement Conditions] (Heating Program) 1. Hold at 40 °C for 5 min 2. Heat to 240 °C at 10 °C / min 3. Hold for 15 min after reaching 240 °C (Various GC Settings) · Gases used: Nitrogen (carrier gas), hydrogen (for detector), air (for detector) · Injection port settings: Heater 200 °C, pressure 93 kPa, total flow (N2) 24.5 mL / min, split ratio 5.3:1. · Column settings: Pressure 93 kPa, flow rate (N2) 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 (N2) 10.0 mL / min (GC retention times of the reference substances used for the identification of each compound) · Internal standard (tridecane): 13.5 min · Tetradecene: 14.9 min · Thiol: 18.8 min · Dialkyl monosulfides (3a: 38.7 min, 4a: 36.0 min, 5a: 34.8 min)

[0061]

Table 1

[0062] From the results in Table 1, in any of Examples 1 to 9, by reacting compound (1a) as alkene (1) and powdered sulfur in the presence of hydrogen, any one of Co3O 4、 CoS, CoS2, NiCo2O4, NiO, Co2SiO4, CoCO3, Ni2SiO4 and Co2SiO4, and zeolite, it was found that thiol (2a) could be obtained at a yield of 3 to 63%. In particular, in Examples 5 to 7, by reacting compound (1a) and sulfur in the presence of hydrogen, any one of NiO, Co2SiO4 and CoCO3, and zeolite, it was found that the total yield of thiol (2a) exceeded 50%. Also, in any of Examples 1 to 9, it was found that the ratio of the yield of thiol (2a) to the total yield of thiol (2a) and dialkyl monosulfide (3a) to (5a) exceeded 20%.

[0063] (Example 10) Thiol (2a) was obtained in the same manner as in Example 6 except that powdered sulfur (S8) was changed from 3.3 molar equivalents to 1.7 molar equivalents as the S element.

[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 at the time of 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 at the time of 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, i.e., 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, i.e., 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]

Table 2

[0071] From the results in Table 2, it was found that in Example 10, even when the powdered sulfur (S8) was changed from 3.3 molar equivalents to 1.7 molar equivalents as the S element, thiol (2a) could be obtained with a yield of 27%. In Example 11, it was found that even when zeolite was not used, thiol (2a) could be obtained with a yield of 64% similar to that in Example 1. Also, in Examples 12 to 13, even when zeolite was not 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 with a yield of 54% or 18%. Furthermore, in Examples 14 to 15, even when zeolite was not used and the reaction temperature was changed from 130 °C to 120 °C or 140 °C, thiol (2a) could be obtained with a yield of 55% or 62%.

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

[0073] (Example 16) A stirrer, 6 mmol of compound (1a) (H2C=C-C 12 H 25 ), 0.4125 molar equivalent of powdered sulfur (S8) (3.3 molar equivalents as the S element), and 6.6 mol% of CoO x -SiO y were charged into an autoclave, and then 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). Then, after cooling to room temperature and opening the pressure valve, 20 mg of tridecane (1.7 parts by mass with respect to 100 parts by mass of compound (1a)) was added to the reaction solution as an internal standard substance, and further, air was blown in to distill off the remaining hydrogen sulfide. After removing the unreacted sulfur and Co3O4 with a centrifuge, thiol (2a) was obtained. The time-course changes of the yield of thiol (2a) and the total yield of dialkyl monosulfides (3a) to (5a) in Example 16 are shown in Figure 3.

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

[0075] (Catalyst property evaluation) CoS and CoS2 before use in Examples 2 and 3, and CoO before use in Example 6 x -SiO y , CoO after use in Example 6 x -SiO y , and XRD measurements were performed on α-Co2SiO4 before use in Example 9 using an X-ray diffractometer (manufactured by Rigaku, model name "MiniFlex600"). The XRD measurements were carried out under the following conditions. The results are shown in Figure 4.

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

[0077] As shown in Figure 4, in Example 6, when CoO x -SiO y was used as a catalyst in the synthesis reaction of the thiol (2a), its crystal structure changed to be close to that of Co x S y used in Examples 2 and 3, and was confirmed to be different from the crystal structure of α-Co2SiO4 used in Example 9.

[0078] Next, CoO before use in Example 6 x -SiO y , and CoO after use in Example 6 x -SiO yElemental analysis was performed using an energy-dispersive X-ray spectrometer (EDS) (manufactured by JEOL, model name "JEM-ARM200F"). The EDS measurements were carried out under the following conditions. The results are shown in Figures 5 and 6.

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

[0080] As shown in Figure 5, for CoO x -SiO y before use, it was confirmed that cobalt (Co), silica (Si), and oxygen (O) were each distributed almost uniformly throughout the catalyst. Also, as shown in Figure 6, for CoO x -SiO y after use, 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] Also, for CoO x -SiO y after use in Example 6, multiple samples were prepared, the organic matter was oxidized using sulfuric acid and aqua regia, and cobalt (Co) was extracted in an aqueous solution. When the cobalt content in the obtained aqueous solution was measured, the cobalt content was less than 0.09 ppm in all samples. From this result, it was confirmed that cobalt (Co) contained in CoO x -SiO y hardly eluted in the synthesis reaction, and it was confirmed that the catalytic activity inherent to the catalyst could be maintained by this production method.

[0082] (Examples 18 - 35) Compound (1a) (H2C=C-C 12 H 25 ) was replaced with the compounds (1b) - (1s) shown in Figure 7, and thiols (2b) - (2s) shown in Figure 8 were synthesized in the same manner as in Example 6. The yields of the obtained thiols (2b) - (2s) are shown in Figure 8. As shown in Fig. 8, in any of Examples 18 to 35, any of compounds (1b) to (1s) and powdered sulfur are reacted in the presence of hydrogen, CoO x -SiO y and zeolite, and it was found that thiols (2b) to (2s) can be obtained in yields of 36 to 94%.

Industrial Applicability

[0083] According to the above method for producing thiols, hydrogen sulfide gas, which is difficult to handle, and expensive organic bases are not required, and there is no need to install an ultraviolet irradiation device, a platinum electrode, etc. Since thiols can be obtained using hydrogen gas and a catalyst that are relatively easily available and easy to handle, thiols can be easily produced in various regions, which is extremely useful.

Claims

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

2. The method for producing a thiol according to claim 1, wherein the pressure of hydrogen supplied when reacting the alkene (1) with sulfur 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) 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) 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) 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.

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