Preparation of a Thiol-Induced Protected Synthesis of a Diatomic Catalyst and Its Application in the Synthesis of tert-Dodecyl Mercaptan

Abstract

The present invention discloses the preparation of a thiol-induced protected synthesis of a dual-atom catalyst and its application in the synthesis of tert-dodecyl mercaptan, belonging to the technical field of tert-dodecyl mercaptan synthesis methods. The present invention prepares a high-density MoK / Al2O3 dual single-atom catalyst from thiol as a raw material, and this catalyst has remarkable effects in the reaction of triisobutene and hydrogen sulfide to prepare tert-dodecyl mercaptan. In the method of the present invention, the catalyst synthesis has a high yield, excellent catalyst activity, and a long service life. In particular, this method can increase the reaction temperature, has a low requirement for the water content of the raw material triisobutene, and low energy consumption, solving the problems of fast deactivation and high energy consumption of the existing catalytic system. Therefore, it has obvious economic advantages and is particularly suitable for large-scale production.

Description

Technical Field

[0001] The present invention belongs to the technical field of the synthesis method of tert-dodecyl mercaptan, and particularly relates to the preparation of a dual-atom catalyst by thiol-induced protection and its application in the synthesis of tert-dodecyl mercaptan. Background Art

[0002] Tert-dodecyl mercaptan (TDM), as a chain transfer agent, is used for the regulation of molecular weight in the polymerization process and is the most widely used polymer molecular weight regulator.

[0003] Currently, commercial tert-dodecyl mercaptan is synthesized by the reaction of dodecene with hydrogen sulfide. The dodecene is composed of tetrapropylene and its isomer triisobutene (TIB). Due to the presence of 2 branched chains in the molecular structure of triisobutene, when using this raw material to synthesize TDM, commercial catalysts on the market generally have problems such as low conversion rate, poor selectivity and stability. For example, US4891445 uses A-15 resin as a catalyst and triisobutene as a reaction raw material. During the reaction process, the conversion rate of triisobutene continuously decreases, and there are serious by-products. If used for industrial production, the costs of catalyst regeneration or replacement and product separation increase significantly. In addition, when using liquid acid catalysts such as aluminum trichloride and boron trifluoride, not only are the reaction conditions harsh (-30°C), but also a large amount of wastewater is generated, resulting in serious environmental pollution. KR20060113045 uses Y zeolite as a catalyst, and the carbon deposition of the catalyst during the reaction process causes serious deactivation of the catalyst. Although CN115850132A has used fluorosilane-modified zeolite and triisobutene organic amine additives to synthesize tert-dodecyl mercaptan, microporous zeolites are prone to carbon and sulfur deposition and deactivation, and mesoporous or macroporous zeolites are expensive. Therefore, in order to be safer, more environmentally friendly and applicable to industrial applications, it is still necessary to improve the catalytic system and improve the catalytic activity and stability of the catalyst. Summary of the Invention

[0004] Aiming at the problems existing in the above-mentioned prior art, the present invention provides the preparation of a dual-atom catalyst by thiol-induced protection and its application in the synthesis of tert-dodecyl mercaptan. The present invention improves the reaction temperature by preparing a high-density MoK / Al2O3 dual single-atom catalyst, thereby reducing the reaction energy consumption, further improving the conversion rate of triisobutene and the selectivity of tert-dodecyl mercaptan, and achieving long-term stable operation. The improved catalyst can react at a mild reaction temperature and lower pressure, and the water content requirement in triisobutene is more mild. The yield of tert-dodecyl mercaptan is greater than 95%, and the stability is greater than 4000 h, which is suitable for industrial production.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] Technical Solution 1: Provide a preparation method of a high-density MoK / Al2O3 dual single-atom catalyst, including the following steps: Mix Al2O3, thiol, and ethanol, adjust the pH to 9-10, then add Mo salt and K salt, react at high temperature and stir until the solution becomes viscous, calcine, cool and wash until neutral, and dry to obtain a high-density MoK / Al2O3 dual single-atom catalyst.

[0007] Further, the addition amount of the thiol is 1-2% of the mass of Al2O3; the molar ratio of the Mo salt to the K salt is (1-10):1.

[0008] Further, the thiol is a tertiary thiol with C8-C16.

[0009] Further, the high-temperature reaction is continuously stirred at 120°C for 5-10 h; the temperature when stirring until the solution becomes viscous is 80°C; the calcination is carried out at 150-250°C for 2-5 h.

[0010] Technical Solution 2: Provide a high-density MoK / Al2O3 dual single-atom catalyst prepared by using the above preparation method.

[0011] Technical Solution 3: Provide an application of the high-density MoK / Al2O3 dual single-atom catalyst in the synthesis of tert-dodecyl mercaptan.

[0012] Technical Solution 4: Provide a preparation method of tert-dodecyl mercaptan, including the following steps: Use triisobutylene and hydrogen sulfide as raw materials, use the high-density MoK / Al2O3 dual single-atom catalyst, and catalytically react to prepare tert-dodecyl mercaptan; the molar ratio of the triisobutylene to the hydrogen sulfide is 1:(1-10).

[0013] Further, the catalytic reaction is carried out in a stirred tank or a fixed bed, the feeding method is upward feeding, and the space velocity of the triisobutylene is 0.1-4 h -1 ; the water content of the triisobutylene is 50-1000 ppm. The parameters of the catalytic reaction are: temperature 50-150°C, pressure 0.4-5 MPa.

[0014] Compared with the prior art, the present invention has the following advantages and technical effects:

[0015] 1) Compared with the defect that the water content of triisobutylene in the prior art is less than 10 ppm, the preparation method of the present invention can stably carry out the reaction with the water content of triisobutylene being 50-1000 ppm, reducing the cost of deep dehydration of raw materials and frequent regeneration of the catalyst in the reaction system.

[0016] 2) Compared with the prior art where the reaction is carried out at a low temperature of about 10°C, the preparation method of the present invention can be carried out at a higher reaction temperature (50 - 150°C), reducing the freezing energy consumption of the reaction system.

[0017] 3) The catalyst prepared by the method of the present invention greatly improves the problem of poor stability in the process of synthesizing tert-dodecyl mercaptan by reacting triisobutene with hydrogen sulfide. Compared with the commercial Amberlyst-15 resin catalyst, after the modified catalyst of the present invention reacts for 4000 h, triisobutene still maintains a conversion rate of more than 95%, and the selectivity of tert-dodecyl mercaptan is 100%. Detailed Description of the Invention

[0018] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and embodiments of the present invention.

[0019] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0020] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0021] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of this application are merely exemplary.

[0022] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0023] The innovation of the present invention lies in inventing a method for large-scale synthesis of a high-density MoK / Al2O3 dual single-atom catalyst, mainly including a thiol-induced protection strategy, and this catalyst has remarkable effects in the reaction of triisobutene and hydrogen sulfide to prepare tert-dodecyl mercaptan. In the method of the present invention, the catalyst synthesis has a high yield, excellent catalyst activity, and a long lifespan. Particularly, this method can increase the reaction temperature, has a low requirement for the water content of the raw material triisobutene, and low energy consumption, solving the problems of fast deactivation and high energy consumption of the existing catalytic system. Therefore, it has obvious economic advantages and is particularly suitable for large-scale production.

[0024] The present invention provides a method for preparing tert-dodecyl mercaptan, comprising the following steps: using triisobutene and hydrogen sulfide as raw materials, and using the high-density MoK / Al2O3 dual single-atom catalyst synthesized by the present invention to obtain tert-dodecyl mercaptan under low-temperature and low-pressure conditions.

[0025] In some preferred embodiments of the present invention, the preparation method of the high-density MoK / Al2O3 dual single-atom catalyst is as follows: adding a certain amount of Al2O3 into an ethanol solution, and then adding an appropriate amount of thiol. The addition amount of thiol is 1-2% of the mass of Al2O3 (including but not limited to 1%, 1.5%, and 2%, preferably 1%), and stirring at room temperature for 1-3 h (including but not limited to 1 h, 2 h, and 3 h, preferably 3 h). Adjust the pH to 9-10 with ammonia water, preferably 10, and then add an appropriate amount of Mo salt and K salt, where the molar ratio of Mo salt to K salt is (1-10):1 (including but not limited to 1:1, 2:1, 3:1, 4:4, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, preferably 2-5:1). After vigorously stirring for 5 min, transfer it to a high-pressure reaction kettle with a polytetrafluoroethylene inner lining and continuously stir at 120 °C for 5-10 h (including but not limited to 5 h, 6 h, 7 h, 8 h, 9 h, and 10 h, preferably 5 h). After condensation, remove the supernatant, dry at 80 °C, and then calcine in a muffle furnace at 150-250 °C (including but not limited to 150 °C, 200 °C, and 250 °C, preferably 200 °C) for 2-5 h (including but not limited to 2 h, 3 h, 4 h, and 5 h, preferably 5 h). After cooling, wash with deionized water until neutral, and dry at 100 °C to obtain the high-density MoK / Al2O3 dual single-atom catalyst

[0026] In the catalyst synthesis step, the thiol is a C8-C16 tertiary thiol, including but not limited to one or any combination of octanethiol, tert-dodecyl mercaptan, and tert-hexadecyl mercaptan. Preferably, it is octanethiol.

[0027] Thiol contains a mercapto group (HS -), it can enhance the bonding ability between Mo and K ions and the Al2O3 support during the high-pressure crystallization process in the reaction kettle under alkaline conditions, enabling Mo and K ions to be highly dispersed in the form of single atoms on the Al2O3 support. Subsequently, part of the ligands are removed by low-temperature calcination, and then the weakly bonded Mo and K ions in excess are washed away. Therefore, Al2O3 is a Lewis acid with relatively weak acidity. Mo single atoms are introduced into the unsaturated Al 3+ sites on the surface, forming some Brønsted acid sites. The introduction of trace amounts of K single atoms increases the electron transfer in the catalyst, promotes the synergistic effect between Lewis acid and Brønsted acid, thereby inhibiting the cracking of triisobutene and hardly any side reactions occur, and the selectivity of tert-dodecyl mercaptan is improved. Due to the synergistic promotion of Mo and K dual single atoms, the reaction temperature of the reactants also increases significantly, and there is no need to react at low temperatures.

[0028] The catalytic reaction of the present invention can be carried out in a stirred kettle or a fixed bed, preferably a fixed bed. Specifically, a mixture of triisobutene and hydrogen sulfide is introduced into a fixed-bed reactor filled with a catalyst. The feeding method is upward feeding, and the space velocity of triisobutene is 0.1 - 4 h -1 (for example, 0.5 h -1 , 1 h -1 , 1.5 h -1 ), preferably 0.2 - 0.8 h -1 ; the molar ratio of hydrogen sulfide to triisobutene is 1∶1 - 10∶1, for example, including but not limited to 1.5∶1, 2∶1, 2.5∶1, 3∶1, 3.5∶1, 4∶1, 4.5∶1, 5∶1, 5.5∶1, 6∶1, 6.5∶1, 7∶1, 7.5∶1, 8∶1, 8.5∶1, 9∶1 and 9.5∶1, preferably 2∶1 - 5∶1, more preferably 3∶1. The reaction temperature is 50 - 150 °C, for example, including but not limited to 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C and 150 °C, preferably 60 - 100 °C, more preferably 60 °C; the pressure is 0.4 - 5 Mpa (gauge pressure), for example, including but not limited to 0.4 Mpa, 1 Mpa, 2 Mpa, 3 Mpa, 4 Mpa and 5 Mpa, preferably 0.6 - 1.2 Mpa, more preferably 0.6 Mpa and 1.2 Mpa. The water content of the triisobutene is 50 - 1000 ppm, preferably 100 - 500 ppm.

[0029] In the present invention, the "room temperature" is calculated as 25 ± 2 °C unless otherwise specified.

[0030] Sources of raw materials used in the following examples of the present invention: Triisobutene is provided by Henan Wenhua Chemical Co., Ltd. with a purity greater than 99.5%; hydrogen sulfide is purchased from Dalian Dete Gas Co., Ltd. with a purity greater than 99%; high-purity nitrogen, argon, and helium are all purchased from Kunming Guangruida Gas Co., Ltd. with purities all greater than 99.99%. Other experimental reagents involved are all purchased from Sinopharm Group and are all reagent grade.

[0031] The analysis method in the following examples of the present invention is the normalization method, and the instrument used is a gas chromatograph purchased from Zhejiang Fuli. The parameters in the gas chromatograph analysis method are: column temperature 50°C, held for 5 min, heated to 280°C at a rate of 10°C / min; detected by FID detector, injection volume 0.5 μL.

[0032] The following examples are further illustrations of the technical solutions of the present invention.

[0033] Example 1

[0034] Preparation of catalyst: Accurately weigh 300 g of Al2O3 and add it to 600 mL of anhydrous ethanol solution, then add 3 g of octanethiol, and stir at room temperature for 3 h. Adjust the pH to 10 with 25 wt% ammonia water, then add 38.6 g of ammonium molybdate ((NH4)2MoO4) and 1.4 g of potassium carbonate (K2CO3), stir vigorously for 5 min, then transfer to a high-pressure reaction kettle with a polytetrafluoroethylene inner lining and stir continuously at 120°C for 5 h. After condensation, remove the supernatant, dry at 80°C, then calcine in a muffle furnace at 200°C for 5 h, cool, wash with deionized water until neutral, and dry at 100°C to obtain a high-density dual single-atom catalyst, denoted as Mo9K1 / Al2O.

[0035] Preparation of tert-dodecyl mercaptan: Take 100 g of the catalyst prepared above and load it into a fixed bed. The water content of triisobutene is 50 ppm, and the feed space velocity of triisobutene is 0.1 h -1 , the molar ratio of hydrogen sulfide to triisobutene is 3:1, the reaction temperature is 60°C, and the pressure is 0.6 Mpa. After running for 12 h, the conversion rate of triisobutene (TIB) is 99%, and the selectivity of tert-dodecyl mercaptan (TDM) is 100%. After continuous running for 4000 h, the conversion rate is 95% and the selectivity is 100%.

[0036] Example 2

[0037] Preparation of catalyst: Accurately weigh 300 g of Al2O3 and add it to 600 mL of anhydrous ethanol solution. Then add 3 g of octanethiol and stir at room temperature for 3 h. Adjust the pH to 10 with 25 wt% ammonia water, then add 26.3 g of ammonium molybdate ((NH4)2MoO4) and 2.8 g of potassium carbonate (K2CO3). After vigorously stirring for 5 min, transfer it to a high-pressure reactor with a polytetrafluoroethylene inner liner and continuously stir at 120 °C for 5 h. After condensation, remove the supernatant, dry it at 80 °C, then calcine it in a muffle furnace at 200 °C for 5 h. After cooling, wash it with deionized water until neutral and dry it at 100 °C to obtain a high-density dual single-atom catalyst, denoted as Mo8K2 / Al2O3.

[0038] Preparation of tert-dodecyl mercaptan: Take 100 g of the catalyst prepared above and load it into a fixed bed. The water content of triisobutylene is 50 ppm, and the feed space velocity of triisobutylene is 0.1 h -1 , and the molar ratio of hydrogen sulfide to triisobutylene is 3:1. The reaction temperature is 60 °C and the pressure is 1.2 Mpa. Run for 12 h, the conversion rate of TIB is 100%, and the selectivity of TDM is 100%. Continuously run for 4000 h, the conversion rate is 98%, and the selectivity is 100%.

[0039] Example 3

[0040] Preparation of catalyst: The same as Example 2.

[0041] Preparation of tert-dodecyl mercaptan: Take 100 g of the catalyst prepared above and load it into a fixed bed. The water content of triisobutylene is 500 ppm, and the feed space velocity of triisobutylene is 0.1 h -1 , and the molar ratio of hydrogen sulfide to triisobutylene is 3:1. The reaction temperature is 60 °C and the pressure is 1.2 Mpa. Run for 12 h, the conversion rate of TIB is 100%, and the selectivity of TDM is 100%; continuously run for 500 h, the conversion rate is 99%, and the selectivity is 100%; continuously run for 2000 h, the conversion rate is 96%, and the selectivity is 100%; continuously run for 4000 h, the conversion rate is 92%, and the selectivity is 100%.

[0042] Example 4

[0043] Preparation of catalyst: The same as Example 2.

[0044] Preparation of tert-dodecyl mercaptan: Take 100 g of the catalyst prepared above and load it into a fixed bed. The water content of triisobutylene is 1000 ppm, and the feed space velocity of triisobutylene is 0.1 h -1, the molar ratio of hydrogen sulfide to triisobutene is 3:1, the reaction temperature is 60 °C, and the pressure is 1.2 Mpa. The initial (running for 12 h) TIB conversion rate is 100%, and the TDM selectivity is 100%; continuously running for 500 h, the conversion rate is 90%, and the selectivity is 100%; continuously running for 2000 h, the conversion rate is 81%, and the selectivity is 100%; continuously running for 4000 h, the conversion rate is 58%, and the selectivity is 100%.

[0045] Example 5

[0046] Preparation of the catalyst: The same as Example 1, except that octanethiol is replaced with tertiary hexadecyl mercaptan in equal mass.

[0047] Preparation of tertiary dodecyl mercaptan: The same as Example 1.

[0048] Running for 12 h, the TIB conversion rate is 98%, and the TDM selectivity is 99%. Continuously running for 4000 h, the conversion rate is 92%, and the selectivity is 100%.

[0049] Example 6

[0050] Preparation of the catalyst: The same as Example 1, except that octanethiol is replaced with tertiary dodecyl mercaptan and tertiary hexadecyl mercaptan in equal mass, and the mass ratio of tertiary dodecyl mercaptan to tertiary hexadecyl mercaptan is 1:1.

[0051] Preparation of tertiary dodecyl mercaptan: The same as Example 1.

[0052] Running for 12 h, the TIB conversion rate is 98%, and the TDM selectivity is 99%. Continuously running for 4000 h, the conversion rate is 94%, and the selectivity is 100%.

[0053] Example 7

[0054] Preparation of the catalyst: The same as Example 1.

[0055] Preparation of tertiary dodecyl mercaptan: The same as Example 1, except that the feed space velocity of triisobutene is 0.8 h -1 .

[0056] Running for 12 h, the TIB conversion rate is 88%, and the TDM selectivity is 100%. Continuously running for 300 h, the conversion rate is 85%, and the selectivity is 100%.

[0057] Example 8

[0058] Preparation of the catalyst: The same as Example 1.

[0059] Preparation of tertiary dodecyl mercaptan, the same as Example 1, except that the reaction temperature is 120 °C.

[0060] After running for 12 h, the conversion rate of TIB was 60%, and the selectivity of TDM was 90%. After continuously running for 200 h, the conversion rate was 46%, and the selectivity was 92%.

[0061] Comparative Example 1

[0062] The preparation of tert-dodecyl mercaptan was the same as that in Example 3, except that the catalyst was replaced with the commercial amberslyst-15 resin catalyst in US4891445 in equal mass.

[0063] After running for 12 h, the conversion rate of TIB was 52%, and the selectivity of TDM was 63%. After continuously running for 800 h, the conversion rate of TIB decreased to 11%, and the selectivity of TDM was 91%.

[0064] Comparative Example 2

[0065] The preparation of tert-dodecyl mercaptan was the same as that in Example 1, except that the catalyst was replaced with the Y zeolite catalyst in KR20060113045A in equal mass.

[0066] After running for 12 h, the conversion rate of TIB was 58%, and the selectivity of TDM was 66%. After continuously running for 300 h, the conversion rate of TIB decreased to 10%, and the selectivity of TDM was 94%.

[0067] Comparative Example 3

[0068] The preparation of tert-dodecyl mercaptan was the same as that in Example 3, except that the catalyst was replaced with the Y zeolite catalyst modified by silane solution in CN115850132A in equal mass.

[0069] After running for 12 h, the conversion rate of TIB was 61%, and the selectivity of TDM was 96%. After continuously running for 1000 h, the conversion rate of TIB decreased to 36%, and the selectivity of TDM was 99%.

[0070] Comparative Example 4

[0071] The preparation of tert-dodecyl mercaptan was the same as that in Example 3, except that the catalyst was replaced with Al2O3 catalyst in equal mass.

[0072] After running for 12 h, the conversion rate of TIB was 25%, and the selectivity of TDM was 99%. After continuously running for 200 h, the conversion rate of TIB decreased to 5%, and the selectivity of TDM was 99%.

[0073] Comparative Example 5

[0074] The preparation of the catalyst was the same as that in Example 1, except that the mass of Al2O3 was 300 g, and the addition amount of octyl mercaptan was 6% of the mass of Al2O3.

[0075] The preparation of tert-dodecyl mercaptan: the same as that in Example 1.

[0076] Run for 12 h, the conversion rate of TIB is 94%, the selectivity of TDM is 100%. Continuously run for 1000 h, the conversion rate is 84%, and the selectivity is 100%.

[0077] Comparative Example 6

[0078] The catalyst was prepared in the same manner as in Example 1, except that the mass of ammonium molybdate ((NH4)2MoO4) was 38.6 g and the addition amount of potassium carbonate (K2CO3) was 0.35 g.

[0079] Preparation of tert-dodecyl mercaptan: The same as in Example 1.

[0080] Run for 12 h, the conversion rate of TIB is 55%, the selectivity of TDM is 86%. Continuously run for 200 h, the conversion rate is 36%, and the selectivity is 92%.

[0081] Comparative Example 7

[0082] Preparation of the catalyst: The same as in Example 1.

[0083] Preparation of tert-dodecyl mercaptan was the same as in Example 1, except that the molar ratio of hydrogen sulfide to triisobutene was 12:1.

[0084] Run for 12 h, the conversion rate of TIB is 96%, the selectivity of TDM is 100%. Continuously run for 300 h, the conversion rate is 95%, and the selectivity is 100%.

[0085] Comparative Example 8

[0086] The catalyst was prepared in the same manner as in Example 1, except that the prepared density MoK / Al2O3 dual single-atom catalyst was impregnated into a PdCl2 solution, taken out and dried at 100 °C to obtain Pd-MoK / Al2O3.

[0087] Preparation of tert-dodecyl mercaptan: The same as in Example 1.

[0088] Run for 12 h, the conversion rate of TIB is 91%, the selectivity of TDM is 66%. Continuously run for 200 h, the conversion rate is 74%, and the selectivity is 81%.

[0089] The above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. Application of a high-density MoK / Al2O3 double single-atom catalyst in the synthesis of tert-dodecyl mercaptan, characterized in that: The preparation method of the high-density MoK / Al2O3 double single-atom catalyst comprises the following steps: mixing Al2O3, thiol and ethanol, adjusting the pH to 9-10, then adding Mo salt and K salt, stirring until the solution becomes viscous after high-temperature reaction, calcining, cooling, washing to neutrality, and drying to obtain a high-density MoK / Al2O3 double single-atom catalyst; the high-temperature reaction is continuously stirred at 120°C for 5-10h; the temperature when stirring until the solution becomes viscous is 80°C.

2. The use according to claim 1, characterized in that: The added amount of the mercaptan is 1-2% of the mass of Al2O3; the molar ratio of the Mo salt to the K salt is (1-10):

1.

3. The use according to claim 2, characterized in that: The mercaptan is a C8-C16 tertiary mercaptan.

4. The use according to claim 1, characterized in that: The calcination is carried out at 150-250° C. for 2-5 hours.

5. A method for preparing tert-dodecyl mercaptan, characterized in that: The following steps are involved: Using trimerized isobutylene and hydrogen sulfide as raw materials, using a high-density MoK / Al2O3 double single-atom catalyst, catalytic reaction to prepare tert-dodecyl mercaptan; the molar ratio of the trimerized isobutylene to the hydrogen sulfide is 1: (1-10); The preparation method of the high-density MoK / Al2O3 double single-atom catalyst comprises the following steps: mixing Al2O3, thiol and ethanol, adjusting the pH to 9-10, then adding Mo salt and K salt, stirring until the solution becomes viscous after high-temperature reaction, calcining, cooling, washing to neutrality, and drying to obtain a high-density MoK / Al2O3 double single-atom catalyst; the high-temperature reaction is continuously stirred at 120°C for 5-10h; the temperature when stirring until the solution becomes viscous is 80°C.

6. The method for preparing tert-dodecyl mercaptan according to claim 5, characterized in that: The catalytic reaction is carried out in a stirred tank or a fixed bed, the feeding method is top feeding, and the space velocity of the trimerized isobutylene is 0.1-4h -1 ; The water content of the trimerized isobutylene is 50-1000ppm.

7. The method for preparing tert-dodecyl mercaptan according to claim 6, characterized in that: The parameters of the catalytic reaction are: temperature 50-150° C., pressure 0.4-5 MPa.