A porous silica-based catalyst for the catalytic synthesis of dodecanethiol and its preparation method

Abstract

This application discloses a porous silicon-based catalyst for the catalytic synthesis of dodecanethiol and its preparation method. The steps are as follows: Silica powder is mixed with a molding aid, and then an aqueous solution containing nitric acid and guar gum powder is added. The mixture is kneaded and extruded to obtain a strip-shaped support. The strip-shaped support is cut into particles and then subjected to rotary spheroidizing to obtain silicon-based microspheres. The silicon-based microspheres are dried, calcined, acid-washed, dried, and calcined again to obtain acid-washed silicon-based microspheres. An impregnation solution is prepared by mixing two to three metal salts (Ni, Co, Mo, W) with phosphoric acid, a complexing agent, and water. The impregnation solution is then used to impregnate the silicon-based microspheres. After drying, calcination, and preparation, a porous silicon-based catalyst is obtained. This catalyst has a micro-mesoporous composite pore structure with a pore volume of up to 0.8 cm³. 3 / g or more, average pore size 9.4nm, specific surface area exceeding 300m² 2 / g, compared with traditional catalysts, has advantages such as high catalytic activity, stable performance and long service life.

Description

Technical Field

[0001] This application relates to the field of catalysts, and in particular to a porous silicon-based catalyst for the catalytic synthesis of dodecanethiol and a method for its preparation. Background Technology

[0002] Dodecyl mercaptan is an important organosulfur compound widely used as a polymerization molecular weight regulator in the synthesis of materials such as styrene-butadiene rubber (SBR), nitrile rubber (NBR), and ABS resin. As a major rubber-producing country, my country has a huge output of SBR and NBR, resulting in a significant market demand for dodecyl mercaptan. As early as the 1970s, Chinese scholars researched the domestic production process of dodecyl mercaptan. Currently, the catalysts used in domestic industry are mainly traditional Friedel-Crafts catalysts, primarily boron trifluoride and aluminum trichloride. These strong acid liquid catalysts not only severely corrode equipment but also cause serious environmental pollution. Other catalysts used include ion exchange resins, molecular sieves, and SO42-. 2- ZrO2-type solid superacids, etc. For example, CN116162048A discloses a method for preparing tert-dodecyl mercaptan using a Y-type molecular sieve catalyst modified with organic acid and pyridine solution. CN110876962A discloses a method for preparing tert-dodecyl mercaptan using an acidic liquid catalyst made of anhydrous aluminum chloride, aromatic auxiliaries, and chloroalkane auxiliaries. However, these catalysts generally suffer from problems such as easy loss of active components, poor stability, and short service life, and are not suitable for fixed-bed reactors, severely restricting their industrial application. Overall, there are still many gaps in domestic patent portfolios or technological breakthroughs regarding catalysts for the synthesis of dodecyl mercaptan, urgently requiring new progress. Summary of the Invention

[0003] In order to solve the above-mentioned technical problems, this application provides a porous silicon-based catalyst for the catalytic synthesis of dodecanethiol and a method for its preparation.

[0004] In a first aspect, the present invention provides a method for preparing a porous silicon-based catalyst for the catalytic synthesis of dodecanethiol, which is achieved by the following technical solution.

[0005] A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0006] S1. After mixing silica powder with molding aids, add an aqueous solution containing nitric acid and guar gum powder, knead and extrude to obtain a strip-shaped carrier;

[0007] S2. After cutting the strip-shaped carrier into particles, perform rotary spherical granulation. During the granulation process, aluminum sol mist droplets are sprayed intermittently. Each continuous spraying time is 1 to 5 minutes, and the time interval between two sprays is about 3 to 10 minutes. Repeat the above spray-rotation process 3 to 8 times until the particles become smooth spherical particles, and obtain silicon-based microspheres.

[0008] S3. The silicon-based microspheres are air-dried, dried, and calcined, then acid-washed, dried, and calcined to obtain acid-washed silicon-based microspheres.

[0009] S4. Prepare an impregnation solution by mixing two or three metal salts of Ni, Co, Mo and W with a certain amount of phosphoric acid, complexing agent and deionized water; then impregnate the silicon-based microspheres obtained in step S3 with the impregnation solution, and finally obtain a porous silicon-based catalyst after air drying, drying and calcination.

[0010] Furthermore, in step S1, the silica powder has a particle size of 30–40 μm, a pore volume of 1.0–1.6 mL / g, and a specific surface area of ​​350–500 m². 2 / g, purity > 99%.

[0011] Furthermore, in step S1, the mass ratio of silica powder, nitric acid, and guar gum powder is 100:(1-3):(1-3).

[0012] Furthermore, in step S1, the molding aid is methylcellulose, and the mass ratio of methylcellulose to silica powder is (1-3):100.

[0013] Furthermore, in step S2, the rotational speed of the rotating ball granulator is 30–90 rpm.

[0014] Furthermore, in step S2, the aluminum sol is an ethanol-water solution of aluminum isopropoxide sol with a mass fraction of 5-10%.

[0015] Furthermore, in step S3, the acid washing uses one of phosphoric acid, nitric acid, oxalic acid, or acetic acid; the concentration of the acid solution is 1-2 wt%.

[0016] Furthermore, in step S4, the metal salt is selected from two or three of the following: basic nickel carbonate, basic cobalt carbonate, molybdenum trioxide, and ammonium tungstate.

[0017] Furthermore, in step S4, the mass ratio of the metal salt to phosphoric acid is (1-9):(1-3).

[0018] Furthermore, in step S4, the complexing agent is selected from one or two of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, citric acid, tartaric acid, and gluconic acid; the mass ratio of the complexing agent to the metal salt is (1-5):(1-9).

[0019] Specifically, a method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0020] S1. Mix 500g of silica powder with 5-15g of methylcellulose to form powder A; add 5-15g of nitric acid and 5-15g of guar gum powder to 280-380g of deionized water to form solution B; place powder A in a kneader, dry mix for 10 minutes, then add solution B to powder A and continue kneading for 15-25 minutes to form precursor C;

[0021] S2. Place the precursor C in an extruder with a perforated plate diameter of Φ3 for extrusion. After extrusion, cut the cylindrical precursor C into cylindrical particles D of 2.5-3.5mm. Then place the cylindrical particles D in a spherical granulator. Adjust the angle between the granulator and the ground to 50-70° and start rotation at 30-90 rpm. At the same time, spray aluminum sol atomized droplets into the middle of the granulator. Each continuous spraying time is 1-5 minutes, and the time interval between two sprays is about 3-10 minutes. Continuously wet the particle surface. Repeat the above spray-rotation process 3-8 times until the particles become smooth spherical particles E. Stop spherical granulation.

[0022] S3. After naturally air-drying the obtained spherical particles E for 24 hours, dry them at a temperature of 90–130℃ for 2–6 hours, and then calcine them at a temperature of 450–550℃ for 2–6 hours to obtain silicon-based microspheres F. Then place the silicon-based microspheres F in 300 mL of acid solution G and vacuum dry them at 50–70℃ for more than 24 hours until the solution evaporates. Then dry the silicon-based microspheres at a temperature of 90–130℃ for 2–6 hours. After drying, calcine them at a temperature of 450–550℃ for 2–6 hours to obtain acid-washed silicon-based microspheres H.

[0023] S4. Place 10-90g of metal salt I in 300g of deionized water, then slowly add 10-30g of phosphoric acid while stirring and heating. Then slowly add 10-50g of complexing agent J to the reaction system and continue the reaction until the solid is completely dissolved. Evaporate the resulting mixed solution to 200mL for later use, forming solution K. Then uniformly impregnate 200mL of solution K into 300g of silicon-based microsphere carrier H, and allow it to air dry naturally for 24h. Then dry it at 90-150℃ for 2-6h, and finally calcine it at 400-600℃ for 2-4h to obtain a porous silicon-based catalyst.

[0024] Secondly, the present invention provides a porous silicon-based catalyst for the catalytic synthesis of dodecanethiol, which is achieved by the following technical solution.

[0025] A porous silica-based catalyst for the catalytic synthesis of dodecanethiol prepared by the above preparation method.

[0026] This application has the following beneficial effects.

[0027] This application describes a porous silica-based catalyst for the catalytic synthesis of dodecyl mercaptan, prepared by loading two or three metal active components (Ni, Co, Mo, W) onto specially formulated aluminum-doped silica and undergoing a special treatment. The catalyst possesses a micro-mesoporous composite structure with a pore volume up to 0.8 cm³. 3 / g or more, average pore size 9.4nm, specific surface area exceeding 300m² 2 / g has the characteristics of wide applicability, high catalytic activity and long service life. It is especially suitable for continuous reaction in fixed bed reactors. Moreover, the preparation method is green, mature, low cost and easy to achieve large-scale and industrialization. Attached Figure Description

[0028] Figure 1 The catalyst prepared in Example 3 of this invention catalyzes the reaction of dodecene with hydrogen sulfide, and the conversion rate of dodecene and the selectivity for dodecyl mercaptan within 0-240 h are described.

[0029] Figure 2 The catalyst prepared in Comparative Example 1 of this invention catalyzes the reaction of dodecene with hydrogen sulfide, and the conversion rate of dodecene and the selectivity for dodecyl mercaptan within 0–240 h are shown. Detailed Implementation

[0030] The present patent application will be further described below with reference to the embodiments.

[0031] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials and reagents used in the following preparation examples and examples are commercially available unless otherwise specified.

[0032] Example 1

[0033] A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0034] (1) Mix 500g of silica powder with 5g of methylcellulose to form powder A; add 5g of nitric acid and 5g of guar gum powder to 280g of deionized water to form solution B; place powder A in a kneader, dry mix for 10min, and then add solution B to powder A and continue kneading for 15min to form precursor C.

[0035] (2) Place the precursor C in an extruder with a diameter of Φ3 for extrusion. After extrusion, cut the cylindrical precursor C into cylindrical particles D with a diameter of 2.5-3.5 mm. Then place the cylindrical particles D in a ball granulator. Adjust the angle between the granulator and the ground to 50° and start the rotation at 30 rpm. At the same time, spray 10 w% aluminum sol ethanol aqueous solution mist droplets into the middle of the granulator. Each spraying time is 1 min and the time interval between two sprays is about 3 min. Continuously wet the particle surface. Repeat the above spray-rotation process 3 times until the particles become smooth spherical particles E. Stop the rolling granulation.

[0036] (3) The obtained spherical particles E were naturally air-dried for 24 hours and then dried at 90°C for 2 hours. Then they were calcined at 450°C for 2 hours to obtain silicon-based microspheres F. The silicon-based microspheres F were then placed in 300 mL of 1 wt% phosphoric acid solution and vacuum dried at 50°C for more than 24 hours until the solution was evaporated. The silicon-based microspheres were then dried at 90°C for 2 hours. After drying, they were calcined at 450°C for 2 hours to obtain acid-washed silicon-based microspheres H.

[0037] (4) Place 10g of basic nickel carbonate and 10g of molybdenum trioxide in 300g of deionized water, then slowly add 10g of phosphoric acid while stirring and heating. Then slowly add 10g of ethylenediaminetetraacetic acid to the reaction system to carry out the reaction until the solid is completely dissolved. Evaporate the resulting mixed solution to 200mL for later use to form solution K. Then uniformly impregnate 200mL of solution K into 300g of silicon-based microsphere carrier H, and then air dry for 24h. Then dry at 90℃ for 2h, and finally calcine at 400℃ for 2h to obtain a porous silicon-based catalyst.

[0038] Example 2

[0039] A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0040] (1) After thoroughly mixing 500g of silica powder with 7g of methylcellulose, powder A is formed; 7g of nitric acid and 7g of guar gum powder are added to 300g of deionized water to form solution B; powder A is placed in a kneader and dry-mixed for 10min, and then solution B is added to powder A and kneaded for another 18min to form precursor C.

[0041] (2) Place the precursor C in an extruder with a diameter of Φ3 for extrusion. After extrusion, cut the cylindrical precursor C into cylindrical particles D with a diameter of 2.5-3.5 mm. Then place the cylindrical particles D in a ball granulator. Adjust the angle between the granulator and the ground to 55° and start the rotation at 40 rpm. At the same time, spray 10 w% aluminum sol ethanol aqueous solution into the middle of the granulator in the form of droplets. Each spraying time is 2 min and the time interval between two sprays is about 5 min. Continuously wet the particle surface. Repeat the above spray-rotation process 4 times until the particles become smooth spherical particles E. Stop the rolling granulation.

[0042] (3) After the obtained spherical particles E are naturally air-dried for 24 hours, they are dried at 100℃ for 3 hours. Then they are calcined at 450℃ for 3 hours to obtain silicon-based microspheres F. The silicon-based microspheres F are then placed in 300 mL of 1.5 wt% phosphoric acid solution and vacuum-dried at 55℃ for more than 24 hours until the solution is evaporated. The silicon-based microspheres are then dried at 100℃ for 3 hours. After drying, they are calcined at 500℃ for 3 hours to obtain acid-washed silicon-based microspheres H.

[0043] (4) Place 10g of molybdenum trioxide and 20g of ammonium tungstate in 300g of deionized water, then slowly add 15g of phosphoric acid while stirring and heating. Then slowly add 20g of tartaric acid to the reaction system to carry out the reaction until the solid is completely dissolved. Evaporate the resulting mixed solution to 200mL for later use to form solution K. Then uniformly impregnate 200mL of solution K into 300g of silicon-based microsphere carrier H, and then air dry for 24h. Then dry at 100℃ for 3h, and finally calcine at 400℃ for 3h to obtain a porous silicon-based catalyst.

[0044] Example 3

[0045] A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0046] (1) Mix 500g of silica powder with 10g of methylcellulose to form powder A; add 10g of nitric acid and 10g of guar gum powder to 310g of deionized water to form solution B; place powder A in a kneader, dry mix for 10min, and then add solution B to powder A and continue kneading for 18min to form precursor C.

[0047] (2) Place the precursor C in an extruder with a diameter of Φ3 for extrusion. After extrusion, cut the cylindrical precursor C into cylindrical particles D with a diameter of 2.5-3.5 mm. Then place the cylindrical particles D in a ball granulator. Adjust the angle between the granulator and the ground to 60° and start the rotation at 60 rpm. At the same time, spray 10 w% aluminum sol ethanol aqueous solution into the middle of the granulator in the form of droplets. Each spraying time is 3 min and the time interval between two sprays is about 6 min. Continuously wet the particle surface. Repeat the above spray-rotation process 5 times until the particles become smooth spherical particles E. Stop the rolling granulation.

[0048] (3) The obtained spherical particles E were naturally air-dried for 24 hours and then dried at 110°C for 3 hours. Then they were calcined at 500°C for 3 hours to obtain silicon-based microspheres F. The silicon-based microspheres F were then placed in 300 mL of 1.3 wt% oxalic acid solution and vacuum-dried at 60°C for more than 24 hours until the solution evaporated. The silicon-based microspheres were then dried at 100°C for 3 hours. After drying, they were calcined at 500°C for 3 hours to obtain acid-washed silicon-based microspheres H.

[0049] (4) Place 20g of basic nickel carbonate and 30g of ammonium tungstate in 300g of deionized water, then slowly add 20g of phosphoric acid while stirring and heating. Then slowly add 30g of aminotriacetic acid to the reaction system to carry out the reaction until the solid is completely dissolved. Evaporate the resulting mixed solution to 200mL for later use to form solution K. Then uniformly impregnate 200mL of solution K into 300g of silicon-based microsphere carrier H, and then air dry for 24h. Then dry at 110℃ for 3h, and finally calcine at 500℃ for 3h to obtain a porous silicon-based catalyst.

[0050] Example 4

[0051] A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0052] (1) Mix 500g of silica powder with 10g of methylcellulose to form powder A; add 10g of nitric acid and 10g of guar gum powder to 330g of deionized water to form solution B; place powder A in a kneader, dry mix for 10min, and then add solution B to powder A and continue kneading for 20min to form precursor C.

[0053] (2) Place the precursor C in an extruder with a diameter of Φ3 for extrusion. After extrusion, cut the cylindrical precursor C into cylindrical particles D with a diameter of 2.5-3.5 mm. Then place the cylindrical particles D in a ball granulator. Adjust the angle between the granulator and the ground to 60° and start the rotation at 70 rpm. At the same time, spray 10 w% aluminum sol ethanol aqueous solution mist droplets into the middle of the granulator. Each spraying time is 3 min and the time interval between two sprays is about 7 min. Continuously wet the particle surface. Repeat the above spray-rotation process 6 times until the particles become smooth spherical particles E. Stop the rolling granulation.

[0054] (3) The obtained spherical particles E were naturally air-dried for 24 hours and then dried at 110°C for 4 hours. Then they were calcined at 500°C for 4 hours to obtain silicon-based microspheres F. The silicon-based microspheres F were then placed in 300 mL of 1.6 wt% oxalic acid solution and vacuum dried at 60°C for more than 24 hours until the solution was evaporated. The silicon-based microspheres were then dried at 110°C for 4 hours. After drying, they were calcined at 500°C for 4 hours to obtain acid-washed silicon-based microspheres H.

[0055] (4) Place 20g of basic cobalt carbonate and 40g of molybdenum trioxide in 300g of deionized water, then slowly add 20g of phosphoric acid while stirring and heating. Then slowly add 35g of aminotriacetic acid to the reaction system to carry out the reaction until the solid is completely dissolved. Evaporate the resulting mixed solution to 200mL for later use to form solution K. Then uniformly impregnate 200mL of solution K into 300g of silicon-based microsphere carrier H, and then air dry for 24h. Then dry at 120℃ for 4h, and finally calcine at 500℃ for 3h to obtain a porous silicon-based catalyst.

[0056] Example 5

[0057] A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0058] (1) Mix 500g of silica powder with 12g of methylcellulose to form powder A; add 12g of nitric acid and 12g of guar gum powder to 350g of deionized water to form solution B; place powder A in a kneader, dry mix for 10min, and then add solution B to powder A and continue kneading for 22min to form precursor C.

[0059] (2) Place the precursor C in an extruder with a diameter of Φ3 for extrusion. After extrusion, cut the cylindrical precursor C into cylindrical particles D with a diameter of 2.5-3.5 mm. Then place the cylindrical particles D in a ball granulator. Adjust the angle between the granulator and the ground to 65° and start the rotation at 80 rpm. At the same time, spray 10 w% aluminum sol ethanol aqueous solution into the middle of the granulator in the form of droplets. Each spraying time is 4 min and the time interval between two sprays is about 8 min. Continuously wet the particle surface. Repeat the above spray-rotation process 6 times until the particles become smooth spherical particles E. Stop the rolling granulation.

[0060] (3) The obtained spherical particles E were naturally air-dried for 24 hours and then dried at 120°C for 5 hours. Then they were calcined at 500°C for 5 hours to obtain silicon-based microspheres F. The silicon-based microspheres F were then placed in 300 mL of 2 wt% acetic acid solution and vacuum dried at 65°C for more than 24 hours until the solution evaporated. The silicon-based microspheres were then dried at 120°C for 5 hours. After drying, they were calcined at 500°C for 5 hours to obtain acid-washed silicon-based microspheres H.

[0061] (4) Place 20g of basic cobalt carbonate, 20g of molybdenum trioxide, and 30g of ammonium tungstate in 300g of deionized water, then slowly add 25g of phosphoric acid while stirring and heating. Then slowly add 20g of diethylenetriaminepentaacetic acid and 20g of citric acid to the reaction system and react until all the solids are dissolved. Evaporate the resulting mixed solution to 200mL for later use to form solution K. Then uniformly impregnate 200mL of solution K into 300g of silicon-based microsphere carrier H, and then air dry for 24h. Then dry at 130℃ for 5h, and finally calcine at 550℃ for 3h to obtain a porous silicon-based catalyst.

[0062] Example 6

[0063] A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0064] (1) Mix 500g of silica powder with 15g of methylcellulose to form powder A; add 15g of nitric acid and 15g of guar gum powder to 380g of deionized water to form solution B; place powder A in a kneader, dry mix for 10min, and then add solution B to powder A and continue kneading for 25min to form precursor C.

[0065] (2) Place the precursor C in an extruder with a diameter of Φ3 for extrusion. After extrusion, cut the cylindrical precursor C into cylindrical particles D with a diameter of 2.5-3.5 mm. Then place the cylindrical particles D in a ball granulator. Adjust the angle between the granulator and the ground to 70° and start the rotation at 90 rpm. At the same time, spray 10 w% aluminum sol ethanol aqueous solution mist droplets into the middle of the granulator. Each spraying time is 5 min and the time interval between two sprays is about 10 min. Continuously wet the particle surface. Repeat the above spray-rotation process 8 times until the particles become smooth spherical particles E. Stop the rolling granulation.

[0066] (3) The obtained spherical particles E were naturally air-dried for 24 hours and then dried at 130°C for 6 hours. Then they were calcined at 550°C for 6 hours to obtain silicon-based microspheres F. The silicon-based microspheres F were then placed in 300 mL of 2 wt% acetic acid solution and vacuum dried at 70°C for more than 24 hours until the solution was evaporated. The silicon-based microspheres were then dried at 130°C for 6 hours. After drying, they were calcined at 550°C for 6 hours to obtain acid-washed silicon-based microspheres H.

[0067] (4) Place 10g of basic nickel carbonate, 40g of molybdenum trioxide and 40g of ammonium tungstate in 300g of deionized water, then slowly add 30g of phosphoric acid while stirring and heating. Then slowly add 30g of tartaric acid and 20g of gluconic acid to the reaction system and react until all the solids are dissolved. Evaporate the resulting mixed solution to 200mL for later use to form solution K. Then uniformly impregnate 200mL of solution K into 300g of silicon-based microsphere carrier H, and then air dry for 24h. Then dry at 150℃ for 6h, and finally calcine at 600℃ for 4h to obtain a porous silicon-based catalyst.

[0068] Comparative Example 1

[0069] A method for preparing a catalyst for the catalytic synthesis of dodecanethiol includes the following steps:

[0070] (1) Take 100g of modified alumina and 50g of SB powder, mix them evenly, and slowly add the glue solution prepared by 4.5g of nitric acid and 120g of water. After kneading and pressing for 20 minutes, a paste that can be extruded is made, and then extruded into strips. The extruded carrier is dried at 110℃ for 6 hours and then calcined at 500℃ for 3 hours to finally obtain carrier A.

[0071] (2) Take 30g of molybdenum oxide and 10g of alkali nickel, add 100mL of distilled water and stir evenly. Then slowly add 8g of phosphoric acid and start reflux heating. Control the temperature at 80-100℃. After 60min, the yellow-green impregnation solution D-1 is obtained.

[0072] (3) Using the equal volume impregnation method, 68 mL of impregnation solution D-1 was impregnated on 80 g of carrier A for 2 h, dried at 110 °C for 6 h, and calcined at 500 °C for 2 h to obtain catalyst CAT-1.

[0073] Performance testing

[0074] (1) The pore structure of the catalyst samples prepared in Comparative Example 1 and Examples 1-6 was analyzed, and the results are shown in Table 1. As can be seen from Table 1, the specific surface area of ​​the catalyst samples prepared in Examples 1-6 is all greater than 300 m². 2 ·g -1 The pore volume is approximately 0.9 cm. 3 ·g -1 The average pore size is approximately 10 nm. Compared to the catalyst sample prepared in Comparative Example 1, it has a larger specific surface area, pore volume, and average pore size.

[0075] Table 1 Comparison of pore structure characterization of catalyst samples in comparative examples and embodiments

[0076]

[0077] a The BET surface area detection method was used.

[0078] b Total orifice volume refers to the single-point method.

[0079] (2) The catalyst samples prepared in Example 3 and Comparative Example 1 of this invention were evaluated using a 50 mL micro fixed-bed evaluation device. The catalyst loading was 30 mL, the reaction temperature was 260 °C, the pressure was 1.0 MPa, the molar ratio of hydrogen sulfide to dodecene was 20:1, and the volume hourly space velocity was 0.5 h⁻¹. -1 (Based on dodecene). The reacted sample was subjected to chromatographic analysis. The conversion rate of dodecene and the selectivity of dodecyl mercaptan were calculated, and the results were evaluated as follows: Figure 1 , Figure 2 As shown in the figure. The results indicate that the catalyst prepared in Example 3 maintains a stable dodecene conversion of over 98% and a selectivity of over 99%, with no performance degradation even after a reaction time exceeding 240 hours. The catalyst prepared in Comparative Example 1, on the other hand, achieves a dodecene conversion of approximately 95% and a selectivity of approximately 94%. Therefore, the catalyst of this invention exhibits superior catalytic performance compared to the comparative example and possesses a longer lifespan, making it particularly suitable for fixed-bed reactions.

[0080] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol, characterized in that: Includes the following steps: S1. After mixing silica powder with molding aids, add an aqueous solution containing nitric acid and guar gum powder, knead and extrude to obtain a strip-shaped carrier; S2. After cutting the strip-shaped carrier into particles, perform rotary spherical granulation. During the granulation process, intermittently spray aluminum sol mist droplets. Each continuous spraying time is 1~5 min, and the time interval between two sprays is 3~10 min. Repeat the above spray-rotation process 3~8 times until the particles become smooth spherical particles to obtain silicon-based microspheres. S3. The silicon-based microspheres are air-dried, dried, and calcined, then acid-washed, dried, and calcined to obtain acid-washed silicon-based microspheres. S4. Prepare an impregnation solution by mixing two or three of the following: basic nickel carbonate, basic cobalt carbonate, molybdenum trioxide, and ammonium tungstate with a certain amount of phosphoric acid, complexing agent, and deionized water; then impregnate the silicon-based microspheres obtained in step S3 with the impregnation solution, and finally obtain a porous silicon-based catalyst after air drying, drying, and calcination.

2. The method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol according to claim 1, characterized in that: In step S1, the silica powder has a particle size of 30-40 μm, a pore volume of 1.0-1.6 mL / g, and a specific surface area of ​​350-500 m². 2 / g, purity > 99%.

3. The method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol according to claim 1, characterized in that: In step S1, the mass ratio of silica powder, nitric acid, and guar gum powder is 100:(1-3):(1-3).

4. The method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol according to claim 1, characterized in that: In step S2, the rotation speed of the rotating ball granulator is 30~90 rpm.

5. The method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol according to claim 1, characterized in that: In step S2, the aluminum sol is an ethanol-water solution of aluminum isopropoxide sol with a mass fraction of 5-10%.

6. The method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol according to claim 1, characterized in that: In step S3, the acid washing uses one of phosphoric acid, nitric acid, oxalic acid, or acetic acid; the concentration of the acid solution is 1-2 wt%.

7. The method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol according to claim 1, characterized in that: In step S4, the mass ratio of two or three of the following: basic nickel carbonate, basic cobalt carbonate, molybdenum trioxide, and ammonium tungstate to phosphoric acid is (1-9):(1-3).

8. The method for preparing a porous silica-based catalyst for the catalytic synthesis of dodecanethiol according to claim 1, characterized in that: In step S4, the complexing agent is selected from one or two of ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, citric acid, tartaric acid, and gluconic acid; the mass ratio of the complexing agent to two or three of basic nickel carbonate, basic cobalt carbonate, molybdenum trioxide, and ammonium tungstate is (1-5):(1-9).

9. A porous silica-based catalyst for the catalytic synthesis of dodecanethiol prepared by any of the preparation methods described in claims 1-8.

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