Ultra-stable Y-type molecular sieve, preparation method thereof and application of ultra-stable Y-type molecular sieve in preparation of tert-dodecanethiol

Abstract

The invention relates to the technical field of preparation of fine chemicals, in particular to an ultra-stable Y-type molecular sieve, a preparation method thereof and application of the ultra-stable Y-type molecular sieve in preparation of tert-dodecanethiol. In order to solve the problems of low conversion rate and poor stability of the existing molecular sieve catalyst for preparing tert-dodecanethiol, the invention provides a preparation method of an ultra-stable Y-type molecular sieve, which comprises the following steps: carrying out water vapor treatment on a Y-type molecular sieve raw material at a certain temperature and in an inert atmosphere to obtain a Y-type molecular sieve A; and treating the Y-type molecular sieve A with an acid solution at a water bath temperature to obtain a Y-type molecular sieve B, and washing, drying and roasting to obtain the ultra-stable Y-type molecular sieve. The ultra-stable Y-type molecular sieve shows excellent catalytic activity, selectivity and stability in the process of preparing tert-dodecanethiol by catalyzing the reaction of tetra-polypropylene and hydrogen sulfide, the selectivity of tert-dodecanethiol is 99% or above, the tert-dodecanethiol is still maintained to be 95% or above of the initial tetra-polypropylene conversion rate after being recycled for 5 times, and the ultra-stable Y-type molecular sieve has a good application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical preparation, and in particular to an ultra-stable Y-type molecular sieve, a preparation method thereof and application thereof in the preparation of tert-dodecyl mercaptan. Background Art

[0002] As an important organic chemical raw material, tert-dodecyl mercaptan plays a vital role in the fields of rubber, plastics, medicine, pesticides, etc. Especially in the production process of polymer synthetic materials such as styrene-butadiene rubber, nitrile rubber and ABS resin, tert-dodecyl mercaptan can effectively adjust the vulcanization speed and crosslinking density, thereby significantly improving the physical and mechanical properties and heat resistance of the material. The unique properties of tert-dodecyl mercaptan make it an indispensable additive in the field of polymer synthetic materials.

[0003] Tert-dodecyl mercaptan can be prepared by the catalytic addition reaction of tetrapropylene and hydrogen sulfide. For this process route, the applicable catalysts mainly include Friedel-Crafts catalysts, resin catalysts and molecular sieve catalysts. Among them, Friedel-Crafts catalysts have the disadvantages of strong equipment corrosion and difficult treatment of acidic wastewater; resin catalysts have the disadvantages of easy decomposition and water sensitivity, which limits their further commercial application. Molecular sieve catalysts not only have good hydrothermal stability, unique pore structure and adjustable acidity, but also are cheap, easy to obtain, reusable and green, and have the most industrial application prospects in the catalytic synthesis of tert-dodecyl mercaptan. Existing studies have shown that modified Y-type molecular sieves can be used as catalysts for the preparation of tert-dodecyl mercaptan, but there are still shortcomings such as low catalyst activity, large dosage and poor catalytic stability, which makes it difficult to achieve industrial application. Therefore, it is still necessary to improve the molecular sieve catalyst, improve the catalytic activity and stability of the molecular sieve catalyst, and then improve the preparation process of tert-dodecyl mercaptan. Summary of the invention

[0004] In order to solve the problems of low conversion rate and poor stability of existing molecular sieve catalysts for preparing tert-dodecyl mercaptan, the present invention provides an ultra-stable Y-type molecular sieve, a preparation method thereof and application in the preparation of tert-dodecyl mercaptan.

[0005] The technical solution of the present invention:

[0006] A method for preparing an ultrastable Y-type molecular sieve comprises the following steps:

[0007] Step 1: treating the Y-type molecular sieve raw material with water vapor at a certain temperature and in an inert atmosphere to obtain a Y-type molecular sieve A;

[0008] Step 2: Treat the Y-type molecular sieve A obtained in step 1 with an acid solution at water bath temperature to obtain an acid-treated Y-type molecular sieve B. The obtained Y-type molecular sieve B is washed, dried, and calcined to obtain an ultra-stable Y-type molecular sieve.

[0009] Furthermore, the temperature in step 1 is 550-750° C., the inert atmosphere is a nitrogen atmosphere, and the time of the water vapor treatment is 0.5-1.5 h.

[0010] Furthermore, the acid solution in step 2 is one of 0.1-0.3 mol / L tartaric acid solution, citric acid solution, phosphoric acid solution, sulfuric acid solution or hydrochloric acid solution, and the mass ratio of the acid solution to the Y-type molecular sieve A obtained in step 1 is 5-10:1.

[0011] Furthermore, in step 2, the water bath temperature is 60-100° C., and the treatment time of the acid solution is 1-3 hours.

[0012] An ultrastable Y-type molecular sieve prepared by the preparation method provided by the invention.

[0013] The invention discloses an application of an ultrastable Y-type molecular sieve prepared by the preparation method provided by the invention in the preparation of tert-dodecyl mercaptan.

[0014] Furthermore, a specific method for preparing tert-dodecyl mercaptan using the ultra-stable Y-type molecular sieve as a catalyst is as follows: adding the ultra-stable Y-type molecular sieve, tetrapropylene and cyclohexane into an autoclave reactor in a certain mass ratio, introducing hydrogen sulfide gas at a certain reaction temperature, and preparing tert-dodecyl mercaptan under a certain gas pressure.

[0015] Furthermore, the mass ratio of the ultra-stable Y-type molecular sieve, tetrapropylene and cyclohexane is 0.5-1.5:10:40.

[0016] Furthermore, the reaction temperature is 60-90° C., and the gas pressure is 0.5 MPa.

[0017] Principle of the present invention:

[0018] During the hydrothermal treatment, the Y-type molecular sieve undergoes dealumination, which leads to an increase in the molecular sieve framework silicon-aluminum ratio and the generation of new framework aluminum species or different types of non-framework aluminum species; the newly generated aluminum species exist in the molecular sieve pores or on the surface of the molecular sieve, affecting the acidity, hydrothermal stability and catalytic performance of the molecular sieve. Acid treatment can remove the residual non-framework aluminum in the molecular sieve pores, increase the mesopore volume and pore size of the molecular sieve, facilitate the diffusion of tetrapropylene inside the molecular sieve, and increase mass transfer; the modified molecular sieve has fewer strong acid centers, which improves the selectivity of tert-dodecane mercaptan, effectively slows down the carbon deposition production rate, and improves the stability of the molecular sieve. Through the synergistic effect of hydrothermal treatment and acid treatment, the catalytic activity and stability of the ultra-stable Y-type molecular sieve in the reaction of tetrapropylene with hydrogen sulfide to prepare tert-dodecane mercaptan are significantly improved.

[0019] Beneficial effects of the present invention:

[0020] The ultra-stable Y-type molecular sieve prepared by the present invention exhibits excellent catalytic activity, selectivity and stability in the process of catalyzing the reaction of tetrapropylene and hydrogen sulfide to prepare tert-dodecyl mercaptan, and the selectivity of tert-dodecyl mercaptan is above 99%, and after being recycled for 5 times, it still maintains above 95% of the initial tetrapropylene conversion rate. The ultra-stable Y-type molecular sieve prepared by the present invention does not need to be regenerated after the catalytic reaction, and can be used for the catalytic reaction again after filtering and separation, and has good application prospects. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0022] Example 1

[0023] This embodiment provides a method for preparing an ultrastable Y-type molecular sieve, and the specific steps are as follows:

[0024] Step 1, weigh 30 g of Y-type molecular sieve, put it into a hydrothermal treatment furnace, and treat the Y-type molecular sieve with water vapor at 650° C. in a nitrogen atmosphere for 1 h to obtain Y-type molecular sieve A;

[0025] Step 2: Weigh 5 g of the Y-type molecular sieve A obtained in step 1, mix the two at a mass ratio of 8:1 of hydrochloric acid solution to Y-type molecular sieve A, treat Y-type molecular sieve A with 0.2 mol / L hydrochloric acid solution at a water bath temperature of 90°C, and obtain Y-type molecular sieve B after treatment for 2 hours. The obtained Y-type molecular sieve B is washed, dried at 120°C and calcined at 400°C for 3 hours to obtain an ultra-stable Y-type molecular sieve.

[0026] The pore structures of the untreated Y-type molecular sieve raw material, the Y-type molecular sieve A obtained in step 1, and the ultrastable Y-type molecular sieve prepared in step 2 used in this example were tested, and the results are shown in Table 1.

[0027] Table 1

[0028] project Y-type molecular sieve raw materials Y-type molecular sieve A Ultra-stable Y-type molecular sieve <![CDATA[Total specific surface area (m 2 / g)]]> 509.42 626.46 602.19 <![CDATA[Micropore specific surface area (m 2 / g)]]> 438.54 506.74 461.14 <![CDATA[External specific surface area (m 2 / g)]]> 70.88 119.72 141.06 <![CDATA[Total pore volume (cm 3 / g)]]> 0.403 0.475 0.497 <![CDATA[Micropore volume (cm 3 / g)]]> 0.186 0.211 0.195 <![CDATA[Mesopore volume (cm 3 / g)]]> 0.217 0.264 0.302

[0029] As shown in Table 1, the specific surface area and micropore surface area of ​​the Y-type molecular sieve increased significantly after high-temperature hydrothermal treatment; the micropore volume increased slightly, but the total pore volume increased significantly, mainly due to the increase in the mesopore volume. The Y-type molecular sieve after hydrothermal treatment was modified with hydrochloric acid again, and the micropore specific surface area and micropore volume of the molecular sieve decreased, while the external specific surface area and mesopore volume increased significantly. This is due to the selective etching during the hydrochloric acid modification process, which caused a slight decrease in the micropore volume and formed more abundant mesopores. In general, the total specific surface area of ​​the Y-type molecular sieve increased significantly after hydrothermal treatment and hydrochloric acid treatment, and formed more abundant mesopores.

[0030] The acid property parameters of the untreated Y-type molecular sieve raw material used in this example, the Y-type molecular sieve A obtained in step 1, and the ultrastable Y-type molecular sieve prepared in step 2 were tested, and the results are shown in Table 2.

[0031] Table 2

[0032]

[0033]

[0034] As shown in Table 2, the total acid content of the Y-type molecular sieve increased significantly after high-temperature hydrothermal treatment, the B acid content remained basically unchanged, and the L acid content increased to 1.4 times that of the untreated Y-type molecular sieve. This is due to the high-temperature hydrothermal treatment causing the framework aluminum of the molecular sieve to fall off and deposit on the surface or in the pores. The Y-type molecular sieve after hydrothermal treatment was modified with hydrochloric acid again, and the total acid content of the molecular sieve increased slightly, the L acid content decreased significantly, but the B acid content increased to 3 times before hydrochloric acid modification. This is due to the removal of non-framework aluminum in the Y-type molecular sieve from the surface or pores during the hydrochloric acid treatment, while the framework aluminum was not eluted. In general, the total acid content of the Y-type molecular sieve raw material increased significantly after hydrothermal treatment and hydrochloric acid treatment, and the L acid content remained basically unchanged compared with the untreated Y-type molecular sieve, but the B acid content was 3 times that of the untreated Y-type molecular sieve raw material.

[0035] Tert-dodecyl mercaptan was prepared using the ultrastable Y-type molecular sieve prepared in this example as a catalyst. The specific preparation steps were as follows: 1 g of the ultrastable Y-type molecular sieve prepared in this example, 10 g of tetrapropylene and 40 g of cyclohexane were added to an autoclave reactor. After the temperature was raised to 80° C., hydrogen sulfide gas was introduced to 0.5 MPa. The temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 71.36%, and the selectivity of tert-dodecyl mercaptan was 99.24%.

[0036] Example 2

[0037] This embodiment provides a method for preparing an ultrastable Y-type molecular sieve, and the specific steps are as follows:

[0038] Step 1, weigh 30 g of Y-type molecular sieve, put it into a hydrothermal treatment furnace, and treat the Y-type molecular sieve with water vapor at 550° C. in a nitrogen atmosphere for 1 h to obtain Y-type molecular sieve A;

[0039] Step 2: Weigh 5 g of the Y-type molecular sieve A obtained in step 1, mix the two at a mass ratio of 8:1 of hydrochloric acid solution to Y-type molecular sieve A, treat Y-type molecular sieve A with 0.2 mol / L hydrochloric acid solution at a water bath temperature of 90°C, and obtain Y-type molecular sieve B after treatment for 2 hours. The obtained Y-type molecular sieve B is washed, dried at 120°C and calcined at 400°C for 3 hours to obtain an ultra-stable Y-type molecular sieve.

[0040] Tert-dodecyl mercaptan was prepared using the ultrastable Y-type molecular sieve prepared in this example as a catalyst. The specific preparation steps are as follows: In an autoclave reactor, 1 g of the ultrastable Y-type molecular sieve prepared in this example, 10 g of tetrapropylene and 40 g of cyclohexane were added, and the temperature was raised to 80°C. Hydrogen sulfide gas was introduced to 0.5 MPa, and the temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 68.62%, and the selectivity of tert-dodecyl mercaptan was 99.52%.

[0041] Example 3

[0042] This embodiment provides a method for preparing an ultrastable Y-type molecular sieve, and the specific steps are as follows:

[0043] Step 1, weigh 30 g of Y-type molecular sieve, put it into a hydrothermal treatment furnace, and treat the Y-type molecular sieve with water vapor at 750° C. in a nitrogen atmosphere for 1 h to obtain Y-type molecular sieve A;

[0044] Step 2: Weigh 5 g of the Y-type molecular sieve A obtained in step 1, mix the two at a mass ratio of 8:1 of hydrochloric acid solution to Y-type molecular sieve A, treat Y-type molecular sieve A with 0.2 mol / L hydrochloric acid solution at a water bath temperature of 90°C, and obtain Y-type molecular sieve B after treatment for 2 hours. The obtained Y-type molecular sieve B is washed, dried at 120°C and calcined at 400°C for 3 hours to obtain an ultra-stable Y-type molecular sieve.

[0045] Tert-dodecyl mercaptan was prepared using the ultrastable Y-type molecular sieve prepared in this example as a catalyst. The specific preparation steps are as follows: In an autoclave reactor, 1 g of the ultrastable Y-type molecular sieve prepared in this example, 10 g of tetrapropylene and 40 g of cyclohexane were added, and the temperature was raised to 80°C. Hydrogen sulfide gas was introduced to 0.5 MPa, and the temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 69.44%, and the selectivity of tert-dodecyl mercaptan was 99.35%.

[0046] Example 4

[0047] This embodiment provides a method for preparing an ultrastable Y-type molecular sieve, and the specific steps are as follows:

[0048] Step 1, weigh 30 g of Y-type molecular sieve, put it into a hydrothermal treatment furnace, and treat the Y-type molecular sieve with water vapor at 650° C. in a nitrogen atmosphere for 1 h to obtain Y-type molecular sieve A;

[0049] Step 2, weigh 5g of the Y-type molecular sieve A obtained in step 1, mix the two at a mass ratio of 8:1 of tartaric acid solution and Y-type molecular sieve A, treat Y-type molecular sieve A with 0.2mol / L tartaric acid solution at a water bath temperature of 90°C, and obtain Y-type molecular sieve B after treatment for 2h. The obtained Y-type molecular sieve B is washed, dried at 120°C and calcined at 400°C for 3h to obtain an ultra-stable Y-type molecular sieve.

[0050] Tert-dodecyl mercaptan was prepared using the ultrastable Y-type molecular sieve prepared in this example as a catalyst. The specific preparation steps are as follows: In an autoclave reactor, 1 g of the ultrastable Y-type molecular sieve prepared in this example, 10 g of tetrapropylene and 40 g of cyclohexane were added, and the temperature was raised to 80°C. Hydrogen sulfide gas was introduced to 0.5 MPa, and the temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 66.44%, and the selectivity of tert-dodecyl mercaptan was 96.33%.

[0051] Example 5

[0052] This embodiment provides a method for preparing an ultrastable Y-type molecular sieve, and the specific steps are as follows:

[0053] Step 1, weigh 30 g of Y-type molecular sieve, put it into a hydrothermal treatment furnace, and treat the Y-type molecular sieve with water vapor at 650° C. in a nitrogen atmosphere for 1 h to obtain Y-type molecular sieve A;

[0054] Step 2, weigh 5g of the Y-type molecular sieve A obtained in step 1, mix the two at a mass ratio of 8:1 of citric acid solution and Y-type molecular sieve A, treat Y-type molecular sieve A with 0.2mol / L citric acid solution at a water bath temperature of 90°C, and obtain Y-type molecular sieve B after treatment for 2h. The obtained Y-type molecular sieve B is washed, dried at 120°C and calcined at 400°C for 3h to obtain an ultra-stable Y-type molecular sieve.

[0055] Tert-dodecyl mercaptan was prepared using the ultrastable Y-type molecular sieve prepared in this example as a catalyst. The specific preparation steps are as follows: In an autoclave reactor, 1 g of the ultrastable Y-type molecular sieve prepared in this example, 10 g of tetrapropylene and 40 g of cyclohexane were added, and the temperature was raised to 80°C. Hydrogen sulfide gas was introduced to 0.5 MPa, and the temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 70.07%, and the selectivity of tert-dodecyl mercaptan was 98.70%.

[0056] Example 6

[0057] This embodiment provides a method for preparing an ultrastable Y-type molecular sieve, and the specific steps are as follows:

[0058] Step 1, weigh 30 g of Y-type molecular sieve, put it into a hydrothermal treatment furnace, and treat the Y-type molecular sieve with water vapor at 650° C. in a nitrogen atmosphere for 1 h to obtain Y-type molecular sieve A;

[0059] Step 2: Weigh 5 g of the Y-type molecular sieve A obtained in step 1, mix the phosphoric acid solution and the Y-type molecular sieve A in a mass ratio of 8:1, treat the Y-type molecular sieve A with 0.2 mol / L phosphoric acid solution at a water bath temperature of 90°C, and obtain the Y-type molecular sieve B after treatment for 2 hours. The obtained Y-type molecular sieve B is washed, dried at 120°C and calcined at 400°C for 3 hours to obtain an ultra-stable Y-type molecular sieve.

[0060] Tert-dodecyl mercaptan was prepared using the ultrastable Y-type molecular sieve prepared in this example as a catalyst. The specific preparation steps are as follows: In an autoclave reactor, 1 g of the ultrastable Y-type molecular sieve prepared in this example, 10 g of tetrapropylene and 40 g of cyclohexane were added, and the temperature was raised to 80°C. Hydrogen sulfide gas was introduced to 0.5 MPa, and the temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 69.36%, and the selectivity of tert-dodecyl mercaptan was 98.99%.

[0061] Example 7

[0062] This embodiment provides a method for preparing an ultrastable Y-type molecular sieve, and the specific steps are as follows:

[0063] Step 1, weigh 30 g of Y-type molecular sieve, put it into a hydrothermal treatment furnace, and treat the Y-type molecular sieve with water vapor at 650° C. in a nitrogen atmosphere for 1 h to obtain Y-type molecular sieve A;

[0064] Step 2, weigh 5g of the Y-type molecular sieve A obtained in step 1, mix the two at a mass ratio of 8:1 of sulfuric acid solution and Y-type molecular sieve A, treat Y-type molecular sieve A with 0.2mol / L sulfuric acid solution at a water bath temperature of 90°C, and obtain Y-type molecular sieve B after treatment for 2h. The obtained Y-type molecular sieve B is washed, dried at 120°C and calcined at 400°C for 3h to obtain an ultra-stable Y-type molecular sieve.

[0065] Tert-dodecyl mercaptan was prepared using the ultrastable Y-type molecular sieve prepared in this example as a catalyst. The specific preparation steps are as follows: In an autoclave reactor, 1 g of the ultrastable Y-type molecular sieve prepared in this example, 10 g of tetrapropylene and 40 g of cyclohexane were added, and the temperature was raised to 80°C. Hydrogen sulfide gas was introduced to 0.5 MPa, and the temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 66.82%, and the selectivity of tert-dodecyl mercaptan was 99.38%.

[0066] Example 8

[0067] In this embodiment, the ultra-stable Y-type molecular sieve used in the catalytic reaction of Example 1 is filtered and recovered, and the ultra-stable Y-type molecular sieve obtained by the catalytic reaction is used as a catalyst to prepare tert-dodecyl mercaptan. The specific preparation steps are as follows: In an autoclave reactor, 1g of ultra-stable Y-type molecular sieve, 10g of tetrapropylene and 40g of cyclohexane obtained by the catalytic reaction are added, and after the temperature is raised to 80°C, hydrogen sulfide gas is introduced to 0.5MPa, and the temperature and pressure are maintained for 2h to stop the reaction. After cooling to room temperature, the molecular sieve is filtered and separated, and it is directly used for the next reaction without any treatment. After being recycled 5 times, the conversion rate of tetrapropylene is 68.44%, and the selectivity of tert-dodecyl mercaptan is 99.81%.

[0068] Comparative Example 1

[0069] In this comparative example, tert-dodecyl mercaptan was prepared using untreated Y-type molecular sieve raw material as a catalyst. The specific preparation steps are as follows: 1 g of untreated Y-type molecular sieve raw material, 10 g of tetrapropylene and 40 g of cyclohexane were added to an autoclave reactor, and the temperature was raised to 80°C. Hydrogen sulfide gas was introduced to 0.5 MPa, and the temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 54.49%, and the selectivity of tert-dodecyl mercaptan was 100%.

[0070] Comparative Example 2

[0071] In this comparative example, the untreated Y-type molecular sieve raw material used in the catalytic reaction of comparative example 1 is filtered and recovered, and the untreated Y-type molecular sieve raw material recovered is used as a catalyst to prepare tert-dodecyl mercaptan. The specific preparation steps are as follows: in an autoclave reactor, 1g of untreated Y-type molecular sieve raw material recovered by the catalytic reaction, 10g of tetrapropylene and 40g of cyclohexane are added, and after heating to 80°C, hydrogen sulfide gas is introduced to 0.5MPa, and the temperature and pressure are maintained for 2h to stop the reaction. After cooling to room temperature, the molecular sieve is filtered and separated, and it is directly used for the next reaction without any treatment. After being recycled for 5 times, the conversion rate of tetrapropylene is 25.20%, and the selectivity of tert-dodecyl mercaptan is 100%.

[0072] Comparative Example 3

[0073] In this comparative example 1, tert-dodecyl mercaptan is prepared using the Y-type molecular sieve A which has only been subjected to hydrothermal treatment in Example 1 as a catalyst. The specific preparation steps are as follows: 1 g of Y-type molecular sieve A, 10 g of tetrapropylene and 40 g of cyclohexane are added to an autoclave reactor. After the temperature is raised to 80°C, hydrogen sulfide gas is introduced to 0.5 MPa. The temperature and pressure are maintained for reaction for 2 hours. The conversion rate of tetrapropylene is 65.12%, and the selectivity of tert-dodecyl mercaptan is 94.86%.

[0074] Comparative Example 4

[0075] The present comparative example provides a Y-type molecular sieve raw material catalyst treated only with hydrochloric acid, and the specific preparation method is as follows: weigh 5 g of the Y-type molecular sieve raw material, mix the two at a mass ratio of 8:1 between the hydrochloric acid solution and the Y-type molecular sieve raw material, treat the Y-type molecular sieve raw material with 0.2 mol / L hydrochloric acid solution at a water bath temperature of 90°C, and obtain the Y-type molecular sieve after treatment for 2 hours. The obtained Y-type molecular sieve is washed, dried at 120°C and calcined at 400°C for 3 hours to obtain a Y-type molecular sieve catalyst treated only with hydrochloric acid.

[0076] Tert-dodecyl mercaptan was prepared using the Y-type molecular sieve treated only with hydrochloric acid prepared in this comparative example as a catalyst. The specific preparation steps are as follows: 1 g of the Y-type molecular sieve catalyst treated only with hydrochloric acid, 10 g of tetrapropylene and 40 g of cyclohexane were added to an autoclave reactor. After the temperature was raised to 80°C, hydrogen sulfide gas was introduced to 0.5 MPa. The temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 60.86%, and the selectivity of tert-dodecyl mercaptan was 100%.

[0077] Comparative Example 5

[0078] The present comparative example provides a Y-type molecular sieve which is first treated with hydrochloric acid and then hydrothermally treated. The specific preparation method is as follows: weigh 10 g of a Y-type molecular sieve raw material, mix the two at a mass ratio of 8:1 between the hydrochloric acid solution and the Y-type molecular sieve raw material, treat the Y-type molecular sieve raw material with a 0.2 mol / L hydrochloric acid solution at a water bath temperature of 90°C, and obtain a Y-type molecular sieve I after treatment for 2 hours. The obtained Y-type molecular sieve I is washed, dried at 120°C, and calcined at 400°C for 3 hours to obtain a Y-type molecular sieve treated with hydrochloric acid; weigh 5 g of the Y-type molecular sieve treated with hydrochloric acid, put it into a hydrothermal treatment furnace, and treat it with water vapor for 1 hour under a nitrogen atmosphere at 650°C to obtain a Y-type molecular sieve treated with hydrochloric acid and then hydrothermally treated.

[0079] Tert-dodecyl mercaptan was prepared using the Y-type molecular sieve prepared in this comparative example which was treated with hydrochloric acid first and then hydrothermally treated as a catalyst. The specific preparation steps were as follows: 1 g of the Y-type molecular sieve which was treated with hydrochloric acid first and then hydrothermally treated, 10 g of tetrapropylene and 40 g of cyclohexane were added into an autoclave reactor. After the temperature was raised to 80° C., hydrogen sulfide gas was introduced to a pressure of 0.5 MPa. The temperature and pressure were maintained for 2 hours. The conversion rate of tetrapropylene was 66.76%, and the selectivity of tert-dodecyl mercaptan was 96.43%.

[0080] By comparing the tetrapropylene conversion rate and tert-dodecyl mercaptan selectivity obtained by the Y-type molecular sieve catalyst prepared in Examples 1 and 8 with those prepared in Comparative Examples 1 to 5 in the process of catalyzing the preparation of tert-dodecyl mercaptan, it can be seen that the ultra-stable Y-type molecular sieve prepared by hydrothermal treatment followed by hydrochloric acid treatment in the present invention can not only effectively maintain a high tert-dodecyl mercaptan selectivity in the process of catalyzing the reaction of tetrapropylene and hydrogen sulfide to prepare tert-dodecyl mercaptan, but also the catalytic activity and stability are significantly improved.

Claims

1. A method for preparing an ultrastable Y-type molecular sieve, characterized in that: The steps include: Step 1: treating the Y-type molecular sieve raw material with water vapor at a certain temperature and in an inert atmosphere to obtain a Y-type molecular sieve A; Step 2: Treat the Y-type molecular sieve A obtained in step 1 with an acid solution at water bath temperature to obtain an acid-treated Y-type molecular sieve B. The obtained Y-type molecular sieve B is washed, dried, and calcined to obtain an ultra-stable Y-type molecular sieve.

2. The method for preparing an ultrastable Y-type molecular sieve according to claim 1, characterized in that: The temperature in step 1 is 550-750° C., the inert atmosphere is a nitrogen atmosphere, and the water vapor treatment time is 0.5-1.5 h.

3. The method for preparing an ultrastable Y-type molecular sieve according to claim 1 or 2, characterized in that: The acid solution in step 2 is one of 0.1-0.3 mol / L tartaric acid solution, citric acid solution, phosphoric acid solution, sulfuric acid solution or hydrochloric acid solution, and the mass ratio of the acid solution to the Y-type molecular sieve A obtained in step 1 is 5-10:

1.

4. The method for preparing an ultrastable Y-type molecular sieve according to claim 3, characterized in that: In step 2, the water bath temperature is 60-100° C., and the treatment time of the acid solution is 1-3 hours.

5. An ultrastable Y-type molecular sieve prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the ultrastable Y-type molecular sieve prepared by the preparation method according to any one of claims 1 to 4 in the preparation of tert-dodecyl mercaptan.

7. The use of the ultrastable Y-type molecular sieve according to claim 6 in the preparation of tert-dodecyl mercaptan, characterized in that: The specific method for preparing tert-dodecyl mercaptan using the ultra-stable Y-type molecular sieve as a catalyst is as follows: adding the ultra-stable Y-type molecular sieve, tetrapropylene and cyclohexane into an autoclave reactor in a certain mass ratio, introducing hydrogen sulfide gas at a certain reaction temperature, and preparing tert-dodecyl mercaptan under a certain gas pressure.

8. Use of the ultrastable Y-type molecular sieve according to claim 6 or 7 in the preparation of tert-dodecyl mercaptan, characterized in that: The mass ratio of the ultra-stable Y-type molecular sieve, tetrapropylene and cyclohexane is 0.5-1.5:10:

40.

9. The use of the ultrastable Y-type molecular sieve according to claim 8 in the preparation of tert-dodecyl mercaptan, characterized in that: The reaction temperature is 60-90° C., and the gas pressure is 0.5 MPa.

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