Catalyst for preparing methyl mercaptan from dimethyl sulfide, preparation method of catalyst and preparation method of methyl mercaptan
By loading catalysts containing tungsten oxide, alkali metal oxides, and other metal oxides onto an alumina support, the problem of low conversion rate of dimethyl sulfide was solved, achieving efficient preparation of methanethiol and meeting industrial needs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-15
- Publication Date
- 2026-04-03
AI Technical Summary
In existing technologies, the conversion of dimethyl sulfide to methanethiol is inefficient and fails to meet industrial demands.
A catalyst consisting of tungsten oxide, alkali metal oxides, and other metal oxides was loaded onto an alumina support using an impregnation-calcination method. By adding a complexing agent to form a soluble chelate, the uniformity and stability of the active impregnation solution were ensured, thus preparing a highly efficient catalyst.
The conversion rate of dimethyl sulfide reached 98% or higher, and the yield of methanethiol reached 95% or higher, showing good prospects for industrial application.
Smart Images
Figure SMS_1
Abstract
Description
Technical Field
[0001] This application relates to the field of catalysis technology, and in particular to catalysts for the production of methanethiol from dimethyl sulfide, methods for their preparation, and methods for the preparation of methanethiol. Background Technology
[0002] Methanethiol (CH3SH), as an important organosulfur compound and fine chemical raw material, has wide applications in industry. Firstly, it is a major precursor in the synthesis of methionine (an essential amino acid), which is widely used as an animal feed additive, resulting in huge global demand in the livestock industry. Secondly, it is a key intermediate in the production of pesticides (such as insecticides and herbicides). Furthermore, it plays an indispensable role in the manufacture of synthetic rubber, pharmaceuticals, dyes, fuel additives, and many other fine chemicals.
[0003] Currently, the mainstream method for large-scale industrial production of methanethiol is a gas-phase catalytic reaction using dimethyl sulfide ((CH3)2S) and hydrogen sulfide (H2S) as raw materials, under the action of a specific catalyst. Although relevant methods have been reported, in actual industrial production, the above-mentioned gas-phase catalytic reaction generally suffers from the problem of low conversion efficiency of dimethyl sulfide. Summary of the Invention
[0004] Based on this, the first aspect of this application provides a method for preparing a catalyst for the production of methanethiol from dimethyl sulfide, the technical solution of which is as follows:
[0005] A method for preparing a catalyst for the production of methanethiol from methyl sulfide includes the following steps:
[0006] A mixed tungsten source, alkali metal source, other metal source, complexing agent and solvent are used to obtain an active impregnation solution, wherein the metal in the other metal source is selected from one or more of magnesium, calcium, phosphorus, cesium, copper, zinc and manganese;
[0007] A carrier comprising alumina is provided, the carrier is immersed in the active impregnation solution, and the carrier is then removed to obtain an impregnated carrier;
[0008] The impregnated support is calcined, the complexing agent is removed, and an active component comprising tungsten oxide, alkali metal oxide, and other metal oxides is loaded onto the support to obtain the catalyst.
[0009] The second aspect of this application provides a catalyst for the production of methanethiol from methyl sulfide, which is prepared by the preparation method described above.
[0010] The third aspect of this application provides a method for preparing methanethiol, the technical solution of which is as follows:
[0011] A method for preparing methanethiol includes the following steps:
[0012] Under catalytic conditions, dimethyl sulfide reacts with hydrogen sulfide to produce methanethiol, wherein the catalyst is as described above, or is prepared by the preparation method described above.
[0013] Compared with traditional solutions, this application has the following advantages:
[0014] This application employs an impregnation-calcination method to load active components, including tungsten oxide, alkali metal oxides, and other metal oxides, onto a support. A complexing agent is added to the impregnation solution, which, through coordination, forms soluble chelates with the tungsten source, alkali metal source, and other metal sources, maintaining a homogeneous and stable solution state at the molecular level. After impregnation-calcination on the alumina support, the active components are uniformly distributed. The prepared catalyst plays a positive role in the conversion of dimethyl sulfide to methanethiol, achieving a conversion rate of 98% or higher for dimethyl sulfide and a yield of 95% or higher for methanethiol, demonstrating promising industrial applications. Detailed Implementation
[0015] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.
[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
[0017] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:
[0018] In this application, terms such as "several", "several kinds", "several times", and "several yuan" are used unless otherwise specified, referring to a quantity greater than or equal to 2. For example, "one or several kinds" means one kind or more than or equal to two kinds.
[0019] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.
[0020] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.
[0021] In this application, numerical intervals (i.e. numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the above-mentioned numerical intervals are considered continuous, and include the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical range, as well as every value between the two numerical endpoints.
[0022] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.
[0023] The first aspect of this application provides a method for preparing a catalyst for the production of methanethiol from methyl sulfide. In some embodiments, the method for preparing the catalyst for the production of methanethiol from methyl sulfide includes the following steps:
[0024] S10, a mixed tungsten source, an alkali metal source, other metal sources, a complexing agent, and a solvent are used to obtain an active impregnation solution, wherein the metals in the other metal sources are selected from one or more of magnesium, calcium, phosphorus, cesium, copper, zinc, and manganese.
[0025] Optionally, the complexing agent is selected from one or more of citric acid, hexamethylenediamine, oxalic acid, and ethylenediaminetetraacetic acid (EDTA). Through coordination, the complexing agent can form soluble chelates with tungsten sources, alkali metal sources, and other metal sources, maintaining a homogeneous and stable solution state of the active impregnation solution at the molecular level.
[0026] Optionally, the tungsten source is selected from one or more of tungsten oxide, tungstic acid, ammonium metatungstate, and ammonium paratungstate. The complexing agent can coordinate with the tungsten-oxygen unit to form a stable, soluble chelate, effectively inhibiting the spontaneous condensation and aggregation of tungstate ions, thereby maintaining a homogeneous and stable solution state at the molecular level. Optionally, the amount of tungsten source added is adjusted so that the mass percentage of tungsten oxide in the catalyst is 10% to 20%.
[0027] Optionally, the alkali metal source is selected from one or more of potassium and sodium sources. Optionally, the potassium source is selected from one or more of potassium hydroxide, potassium carbonate, potassium nitrate, and potassium sulfate. Optionally, the sodium source is selected from one or more of sodium hydroxide, sodium carbonate, sodium nitrate, and sodium sulfate. Optionally, the amount of alkali metal source added is adjusted so that the mass percentage of the alkali metal oxide in the catalyst is 0.5% to 10%.
[0028] Optionally, the other metal source is selected from one or more of magnesium salts, calcium salts, phosphate salts, cesium salts, copper salts, zinc salts, and manganese salts. Optionally, the magnesium salt is selected from magnesium nitrate. Optionally, the calcium salt is selected from calcium acetate. Optionally, the phosphate salt is selected from ammonium dihydrogen phosphate. Optionally, the zinc salt is selected from zinc nitrate. Optionally, the amount of the other metal source is adjusted so that the mass percentage of the other metal oxide in the catalyst is 0.1% to 5%.
[0029] Optionally, the solvent includes one or more of water and ammonia.
[0030] S20. Provide a carrier, the carrier comprising aluminum oxide, immerse the carrier in the active impregnation solution, and remove it to obtain an impregnated carrier.
[0031] Optionally, the method for preparing the carrier includes the following steps:
[0032] S21. Calcining the aluminum source yields alumina powder.
[0033] Optionally, the aluminum source is selected from one or more of boehmite, aluminum hydroxide, and aluminum nitrate.
[0034] Optionally, the alumina powder comprises at least one of α-Al₂O₃, β-Al₂O₃, and γ-Al₂O₃. Optionally, the alumina powder comprises γ-Al₂O₃, and the mass ratio of γ-Al₂O₃ in the alumina powder is ≥70%. For example, the mass ratio of γ-Al₂O₃ in the alumina powder is 70%, 75%, 80%, 85%, 90%, or 95%.
[0035] S22. The alumina powder is shaped into granules to obtain the carrier.
[0036] Optionally, the alumina powder can be shaped into granules by extrusion molding or roll forming. The granules can be spherical, cylindrical, or clover-shaped.
[0037] Optionally, the particle size of the carrier is in the range of 2 mm to 6 mm. Optionally, the particle size of the carrier is in the range of 3 mm to 5 mm.
[0038] Optionally, the carrier is immersed in the active impregnation solution using an equal-volume impregnation method or an over-volume impregnation method. Optionally, immersing the carrier in the active impregnation solution using an equal-volume impregnation method includes the following step: immersing the carrier in the active impregnation solution with a volume equal to the water absorption volume of the carrier. Optionally, immersing the carrier in the active impregnation solution using an over-volume impregnation method includes the following step: immersing the carrier in the active impregnation solution with a volume of 1.5 to 3 times the water absorption volume of the carrier.
[0039] S30. The impregnated support is calcined, the complexing agent is removed, and an active component including tungsten oxide, alkali metal oxide and other metal oxides is loaded onto the support to obtain the catalyst.
[0040] Optionally, the calcination temperature of the impregnated carrier is 400℃~600℃. The calcination time of the impregnated carrier is 2h~5h. The atmosphere for calcining the impregnated carrier is selected from air, nitrogen, or an inert gas. A drying step is also included before calcining the impregnated carrier. Optionally, the drying temperature is 20℃~150℃. Optionally, the drying time is 1h~10h.
[0041] The above-described embodiments utilize an impregnation-calcination method to load active components, including tungsten oxide, alkali metal oxides, and other metal oxides, onto a support. A complexing agent is added to the impregnation solution, which, through coordination, forms soluble chelates with the tungsten source, alkali metal source, and other metal sources, maintaining a homogeneous and stable solution state at the molecular level. After impregnation-calcination on the alumina support, the active components are uniformly distributed. The prepared catalyst plays a positive role in the conversion of dimethyl sulfide to methanethiol, achieving a conversion rate of 98% or higher for dimethyl sulfide and a yield of 95% or higher for methanethiol, demonstrating promising industrial applications.
[0042] The second aspect of this application provides a catalyst for the production of methanethiol from methyl sulfide. In one embodiment, the catalyst for the production of methanethiol from methyl sulfide is prepared by the preparation method described above.
[0043] A third aspect of this application provides a method for preparing methanethiol. In one embodiment, the method for preparing methanethiol includes the following steps:
[0044] Under catalytic conditions, dimethyl sulfide reacts with hydrogen sulfide to produce methanethiol, wherein the catalyst is as described above, or is prepared by the preparation method described above.
[0045] Optionally, the molar ratio of the dimethyl sulfide to the hydrogen sulfide is (0.8~1.2):(0.8~1.2).
[0046] Optionally, the reaction temperature is 320℃~360℃. Optionally, the WHSV is 1000 h⁻¹. -1 ~3000h -1 .
[0047] In the method for preparing methanethiol according to this embodiment, catalytic conversion of dimethyl sulfide to methanethiol is performed. The conversion rate of dimethyl sulfide can reach 98% or higher, and the yield of methanethiol can reach 95% or higher, showing good prospects for industrial application.
[0048] The following description is further illustrated with specific embodiments and comparative examples. Unless otherwise specified, the raw materials involved in the following specific embodiments and comparative examples are all commercially available. Unless otherwise specified, the instruments used are all commercially available. Unless otherwise specified, the processes involved are conventionally selected by those skilled in the art.
[0049] Example 1
[0050] This embodiment provides a catalyst and its preparation method, the steps of which are as follows:
[0051] Carrier preparation: Boehmite was calcined at 600℃ for 3 hours to obtain alumina powder with γ-Al2O3 content >80wt%. 50g of the alumina powder was then subjected to rolling granulation to obtain spherical carriers with a particle size of 3mm~4mm.
[0052] Preparation of active impregnation solution: Weigh ammonium metatungstate (12g as WO3), potassium hydroxide (1.5g as K2O), magnesium nitrate (0.5g as MgO) and citric acid 15g, dissolve them together in deionized water, and make up to a total volume equal to the water absorption volume of the above spherical carrier (about 45mL). Stir until completely dissolved to obtain a clear impregnation solution.
[0053] Loading and activation: The active impregnation solution was uniformly added dropwise to a spherical support using an equal-volume impregnation method and allowed to stand at room temperature for 12 hours. It was then dried at 120°C for 4 hours and calcined in air at 500°C for 3 hours to obtain catalyst CAT-1. Calculations showed that the mass percentages of WO3, K2O, and MgO in the catalyst were approximately 16.0%, 2.0%, and 0.67%, respectively.
[0054] Example 2
[0055] This embodiment provides a catalyst and its preparation method, the steps of which are as follows:
[0056] Carrier preparation: Aluminum hydroxide was calcined at 550℃ for 4 hours to obtain alumina powder. 55g of the alumina powder was extruded into cylindrical carriers and calcined at 500℃ for 2 hours to set the shape. The particle size of the carrier was 3mm.
[0057] Preparation of active impregnation solution: Weigh ammonium paratungstate (15g as WO3), sodium carbonate (3g as Na2O), ammonium dihydrogen phosphate (1g as P2O5) and oxalic acid 10g, dissolve them together in deionized water, and prepare a clear impregnation solution with a volume approximately 1.8 times the water absorption volume of the above cylindrical carrier.
[0058] Loading and activation: The support was completely immersed in the active impregnation solution for 2 hours using the overvolume impregnation method. After removal, it was dried at 100℃ for 6 hours, and then calcined at 450℃ for 4 hours under a nitrogen atmosphere to obtain catalyst CAT-2. Calculations showed that the mass percentages of WO3, Na2O, and P2O5 in the catalyst were approximately 18.5%, 3.7%, and 1.2%, respectively.
[0059] Example 3
[0060] This embodiment provides a catalyst and its preparation method, the steps of which are as follows:
[0061] Carrier preparation: Boehmite was calcined at 600℃ for 3 hours to obtain alumina powder with γ-Al2O3 content >80wt%. 50g of the alumina powder was then subjected to rolling granulation to obtain spherical carriers with a particle size of 3mm~4mm.
[0062] Preparation of active impregnation solution: Weigh 10g of tungstic acid (as WO3), 0.6g of potassium nitrate (as K2O), 0.3g of zinc nitrate (as ZnO), and 5g of ethylenediaminetetraacetic acid (EDTA), dissolve them together in an appropriate amount of ammonia water, adjust the pH to alkaline using ammonia water, and bring the volume up to a final volume equal to the water absorption volume of the above spherical carrier to obtain a clear impregnation solution.
[0063] Loading and activation: The catalyst CAT-3 was loaded using an equal-volume impregnation method. The active impregnation solution was uniformly added dropwise to a spherical support and allowed to stand at room temperature for 10 hours. After drying at 150℃ for 2 hours, it was calcined in air at 550℃ for 2.5 hours to obtain the catalyst. Calculations showed that the mass percentages of WO3, K2O, and ZnO in the catalyst were approximately 14.3%, 0.86%, and 0.43%, respectively.
[0064] Example 4
[0065] This embodiment provides a catalyst and its preparation method, the steps of which are as follows:
[0066] Carrier preparation: Commercially available γ-Al2O3 clover-shaped carrier (particle size about 4 mm) was used directly.
[0067] Preparation of active impregnation solution: Weigh ammonium metatungstate (15g as WO3), potassium sulfate (4g as K2O), calcium acetate (2g as CaO) and citric acid 20g, dissolve them together in deionized water, and prepare a clear impregnation solution with a volume approximately 2.5 times the water absorption volume of the above clover-type carrier.
[0068] Loading and activation: The support was completely immersed in the active impregnation solution for 3 hours using the overvolume impregnation method. After removal, it was dried at 80℃ for 10 hours, and then calcined in air at 480℃ for 5 hours to obtain catalyst CAT-4. Calculations showed that the mass percentages of WO3, K2O, and CaO in the catalyst were approximately 19.4%, 4.8%, and 2.4%, respectively.
[0069] Comparative Example 1
[0070] This comparative example provides a catalyst and its preparation method, which are basically the same as those in Example 1, except that no complexing agent is added. The steps are as follows:
[0071] Carrier preparation: Boehmite was calcined at 600℃ for 3 hours to obtain alumina powder with γ-Al2O3 content >80wt%. 50g of the alumina powder was then subjected to rolling granulation to obtain spherical carriers with a particle size of 3mm~4mm.
[0072] Preparation of active impregnation solution: Weigh ammonium metatungstate (12g as WO3), potassium hydroxide (1.5g as K2O) and magnesium nitrate (0.5g as MgO), dissolve them together in deionized water, and make up to a total volume equal to the water absorption volume of the above spherical carrier (about 45mL). The impregnation solution is turbid.
[0073] Loading and activation: The active impregnation solution was uniformly added dropwise to the spherical support using the equal-volume impregnation method and allowed to stand at room temperature for 12 hours. It was then dried at 120°C for 4 hours and calcined in air at 500°C for 3 hours to obtain catalyst Ref-1.
[0074] Comparative Example 2
[0075] This comparative example provides a catalyst and its preparation method, which are basically the same as those in Example 1, except that the alkali metal source (potassium hydroxide) is replaced with an equimolar amount of ammonium nitrate (i.e., the active components are only WO3 and MgO), and no complexing agent is added. The steps are as follows:
[0076] Carrier preparation: Boehmite was calcined at 600℃ for 3 hours to obtain alumina powder with γ-Al2O3 content >80wt%. 50g of the alumina powder was then subjected to rolling granulation to obtain spherical carriers with a particle size of 3mm~4mm.
[0077] Preparation of active impregnation solution: Weigh ammonium metatungstate (12g as WO3), ammonium nitrate and magnesium nitrate (0.5g as MgO), dissolve them together in deionized water, and make up to a total volume equal to the water absorption volume of the above spherical carrier (about 45mL). The impregnation solution is turbid.
[0078] Loading and activation: The active impregnation solution was uniformly added dropwise to the spherical support using the equal-volume impregnation method and allowed to stand at room temperature for 12 hours. It was then dried at 120°C for 4 hours and calcined in air at 500°C for 3 hours to obtain catalyst Ref-2.
[0079] The catalysts of the above examples and comparative examples were evaluated using a fixed-bed reactor. The method involved filling the catalyst bed of the fixed-bed reactor with the catalyst, introducing dimethyl sulfide and hydrogen sulfide from the top of the reactor, controlling the molar ratio of dimethyl sulfide to hydrogen sulfide at 1:1, the reaction temperature at 340°C, and the WHSV at 2000 h⁻¹. -1 The conversion rate of dimethyl sulfide and the yield of methanethiol were calculated, and the results are shown in Table 1.
[0080] Table 1
[0081]
[0082] As can be seen, the addition of complexing agents to the active impregnation solutions in each embodiment allows the complexing agents to form soluble chelates with tungsten sources, alkali metal sources, and other metal sources through coordination, maintaining a homogeneous and stable solution state at the molecular level. After impregnation and calcination on the alumina support, the active components are evenly distributed, and the prepared catalyst plays a positive role in the conversion of dimethyl sulfide to methanethiol, achieving a conversion rate of 98% or higher for dimethyl sulfide and a yield of 95% or higher for methanethiol. The active impregnation solution in Comparative Example 1 did not contain the complexing agent citric acid; the active components were WO3, K2O, and MgO. The active impregnation solution in Comparative Document 2 did not contain potassium hydroxide or the complexing agent citric acid; the active components were WO3 and MgO. The catalytic effect was poor, with lower conversion rates for dimethyl sulfide and methanethiol.
[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.
[0084] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.
Claims
1. A method for preparing a catalyst for the production of methanethiol from methyl sulfide, characterized in that, Includes the following steps: A mixed tungsten source, alkali metal source, other metal source, complexing agent and solvent are used to obtain an active impregnation solution, wherein the metal in the other metal source is selected from one or more of magnesium, calcium, phosphorus, cesium, copper, zinc and manganese; A carrier comprising alumina is provided, the carrier is immersed in the active impregnation solution, and the carrier is then removed to obtain an impregnated carrier; The impregnated support is calcined, the complexing agent is removed, and an active component comprising tungsten oxide, alkali metal oxide, and other metal oxides is loaded onto the support to obtain the catalyst.
2. The method for preparing the catalyst for the production of methanethiol from methyl sulfide according to claim 1, characterized in that, The complexing agent is selected from one or more of citric acid, hexamethylenediamine, oxalic acid, and ethylenediaminetetraacetic acid.
3. The method for preparing the catalyst for the production of methanethiol from methyl sulfide according to claim 1, characterized in that, Includes at least one of the following features: (1) The tungsten source is selected from one or more of tungsten oxide, tungstic acid, ammonium metatungstate and ammonium paratungstate; (2) The alkali metal source is selected from one or more of potassium source and sodium source; optionally, the potassium source is selected from one or more of potassium hydroxide, potassium carbonate, potassium nitrate and potassium sulfate; optionally, the sodium source is selected from one or more of sodium hydroxide, sodium carbonate, sodium nitrate and sodium sulfate. (3) The other metal source is selected from one or more of magnesium salts, calcium salts, phosphate salts, cesium salts, copper salts, zinc salts and manganese salts; optionally, the magnesium salt is selected from magnesium nitrate; optionally, the calcium salt is selected from calcium acetate; optionally, the phosphate salt is selected from ammonium dihydrogen phosphate; optionally, the zinc salt is selected from zinc nitrate. (4) The solvent includes one or more of water and ammonia.
4. The method for preparing the catalyst for the production of methanethiol from methyl sulfide according to claim 1, characterized in that, Includes at least one of the following features: (1) Adjust the amount of tungsten source added so that the mass percentage of tungsten oxide in the catalyst is 10%~20%; (2) Adjust the amount of alkali metal source added so that the mass percentage of the alkali metal oxide in the catalyst is 0.5% to 10%; (3) Adjust the amount of other metal sources added, wherein the mass percentage of the other metal oxides in the catalyst is 0.1% to 5%.
5. The method for preparing the catalyst for the production of methanethiol from methyl sulfide according to any one of claims 1 to 4, characterized in that, The method for preparing the carrier includes the following steps: The aluminum source is calcined to obtain alumina powder. The alumina powder is shaped into granules to obtain the carrier.
6. The method for preparing the catalyst for the production of methanethiol from methyl sulfide according to claim 5, characterized in that, Includes at least one of the following features: (1) The aluminum source is selected from one or more of boehmite, aluminum hydroxide and aluminum nitrate; (2) The alumina raw powder includes at least one of α-Al2O3, β-Al2O3 and γ-Al2O3; optionally, the alumina raw powder includes γ-Al2O3, and the mass ratio of γ-Al2O3 in the alumina raw powder is ≥70%; (3) The method for forming the alumina powder into granules is extrusion molding or roll forming; (4) The particle size of the carrier is in the range of 2 mm to 6 mm; optionally, the particle size of the carrier is in the range of 3 mm to 5 mm. (5) The carrier is immersed in the active impregnation solution by means of equal volume impregnation or over-volume impregnation; Optionally, the carrier is immersed in the active impregnation solution by means of equal volume impregnation, which includes the following steps: immersing the carrier in the active impregnation solution with the same water absorption volume as the carrier; Optionally, the carrier is immersed in the active impregnation solution by means of over-volume impregnation, which includes the following steps: immersing the carrier in the active impregnation solution with a volume of 1.5 to 3 times the water absorption volume of the carrier.
7. The method for preparing a catalyst for the production of methanethiol from methyl sulfide according to any one of claims 1 to 4 and 6, characterized in that, Includes at least one of the following features: (1) The temperature for calcining the impregnated carrier is 400℃~600℃; (2) The calcination time for the impregnated carrier is 2h~5h; (3) The atmosphere for calcining the impregnated carrier is selected from air, nitrogen or an inert gas; (4) Before calcining the impregnated carrier, a drying step is also included; optionally, the drying temperature is 20℃~150℃; optionally, the drying time is 1h~10h.
8. A catalyst for the production of methanethiol from dimethyl sulfide, characterized in that, It is prepared by any one of the preparation methods according to claims 1 to 7.
9. A method for preparing methanethiol, characterized in that, Includes the following steps: Under catalytic conditions, methyl sulfide reacts with hydrogen sulfide to produce methanethiol, wherein the catalyst is as described in claim 8, or is prepared by any one of claims 1 to 7.
10. The method for preparing methanethiol according to claim 9, characterized in that, Includes at least one of the following features: (1) The molar ratio of the dimethyl sulfide to the hydrogen sulfide is (0.8~1.2):(0.8~1.2); (2) The reaction temperature is 320℃~360℃.