Preparation method and application of modified Y molecular sieve

Abstract

The invention provides a preparation method of a modified Y molecular sieve, a nickel element and a stable element are loaded on the Y molecular sieve through dipping treatment, macropores are formed through roasting, and the stable element is one or more of lanthanum, sodium and potassium elements. The invention also provides the modified Y molecular sieve and application thereof. The invention further provides a preparation method of the tert-dodecyl mercaptan. The modified Y molecular sieve and the preparation method of the tert-dodecyl mercaptan using the modified Y molecular sieve as the catalyst, provided by the invention, have the advantages of simple and convenient process, high catalytic efficiency, no need of high cost and strong industrial practicability, so that the modified Y molecular sieve has very important economic value and social value.

Description

Technical Field

[0001] The invention relates to the technical field of catalysts, and in particular to a preparation method and application of a modified Y molecular sieve. The invention also relates to a preparation method of tert-dodecyl mercaptan. Background Art

[0002] Tert-dodecyl mercaptan (TDM) can be used as a chain transfer agent to adjust the molecular weight during the polymerization process. It is a typical polymer molecular weight regulator. Its downstream applications include the production of ABS, styrene-butadiene rubber, nitrile rubber, polystyrene and other products.

[0003] Tert-dodecyl mercaptan can be prepared by reacting triisobutylene (TIB) with hydrogen sulfide. For example, patent US4582939 uses A-15 resin as a catalyst to catalyze the addition reaction of triisobutylene and hydrogen sulfide in a stainless steel tube. At 73-108°C, the catalyst is deactivated after 12 hours of reaction, the mercaptan yield is 92%, the olefin conversion rate is 88%, a large amount of tert-butyl mercaptan and tert-octyl mercaptan are generated, and the catalyst carbon deposition is obvious; patent US4891445 uses A-15 resin as a catalyst, and the reaction temperature is below 20°C to prepare tert-dodecyl mercaptan. The temperature is reduced and the product selectivity is increased. However, when reacting at low temperature, the refrigeration energy consumption is high. If it is used for industrial production, the cost will increase significantly; patent KR20060113045A uses Y molecular sieve as a catalyst and adopts a reaction temperature below 20°C to avoid the cracking of TIB to generate tert-butyl mercaptan and tert-octyl mercaptan, thereby improving the selectivity of the product.

[0004] When Y molecular sieve is used as a catalyst to synthesize tert-dodecyl mercaptan, the catalyst is easily deactivated, mainly due to carbon deposition. In addition, the catalyst is highly acidic, and the product selectivity can only be improved when the reaction is carried out at a low temperature. However, an increase in temperature will cause the selectivity of TIB cracking byproducts tert-butyl mercaptan and tert-octyl mercaptan to increase sharply, so the industrial practicality is not strong.

[0005] The synthesis of tert-dodecyl mercaptan using triisobutylene as raw material was only reported by some foreign scholars in the last century, and there has been little further research at home and abroad in recent years. Chinese patent CN 115838345A discloses a method for preparing tert-dodecyl mercaptan, which is to coat a layer of dense silicon dioxide film, namely Y@SiO 2 , used to catalyze the reaction of triisobutylene and hydrogen sulfide to prepare tert-dodecyl mercaptan. This method can solve the defect of easy deactivation of Y molecular sieve catalyst, significantly prolong the service life of the catalyst, and has high selectivity of the target product and excellent catalytic activity. It can be seen that the modified Y molecular sieve has great application potential as a catalyst in the production of tert-dodecyl mercaptan, providing a new research direction for the economical and stable production process of tert-dodecyl mercaptan. Summary of the invention

[0006] In order to make up for the deficiencies in the prior art, an object of the present invention is to provide a method for preparing a modified Y molecular sieve. The modified Y molecular sieve prepared by the preparation method has excellent catalytic activity and stability, and is very suitable for catalyzing the addition reaction of triisobutylene and hydrogen sulfide to prepare tert-dodecyl mercaptan.

[0007] Another object of the present invention is to provide a modified Y molecular sieve and application thereof.

[0008] Another object of the present invention is to provide a method for preparing tert-dodecyl mercaptan.

[0009] The first aspect of the present invention provides a method for preparing a modified Y molecular sieve, the method comprising the following steps:

[0010] S1: performing a first impregnation treatment on the unmodified Y molecular sieve in a solution of a nickel source, and obtaining a molecular sieve intermediate loaded with nickel after drying; and

[0011] S2: subjecting the molecular sieve intermediate to a second impregnation treatment in a solution of a stabilizing element source, obtaining a Y molecular sieve loaded with nickel and a stabilizing element after drying, and obtaining the modified Y molecular sieve after calcination, wherein the stabilizing element is one or more of lanthanum, sodium, and potassium.

[0012] The inventor of the present invention finds after a large amount of research: after roasting, most of the micropores of Y molecular sieve disappear, form macropore (maximum pore size can reach about 100nm), when used for catalyzing the addition reaction of triisobutylene and hydrogen sulfide, the diffusion resistance of triisobutylene inside molecular sieve can be effectively reduced, increase mass transfer, thus reduce carbon deposition, catalyst life can be greatly improved, now, the Lewis acid acidity of molecular sieve is reduced, the selectivity of TIB cracking byproduct tert-butyl mercaptan and tert-octyl mercaptan can be significantly reduced, the selectivity of target product tert-dodecyl mercaptan is correspondingly increased, but triisobutylene conversion rate is reduced, after loading nickel element on molecular sieve, molecular sieve acidity can be increased, thus improve the conversion rate of triisobutylene, while loading stabilizing elements such as lanthanum, sodium, potassium can stabilize nickel element, reduce its loss, thus improve catalyst service life. By the synergistic effect of macropore, nickel element and three kinds of factors of stabilizing elements, modified Y molecular sieve has excellent catalytic performance, and its service life can also be greatly extended simultaneously.

[0013] In the preparation method of the modified Y molecular sieve provided by the present invention, the Y molecular sieve can be a Y-type molecular sieve commonly used in the art, and the pore size of the Y molecular sieve before modification does not exceed 2nm. In some preferred embodiments, the Y molecular sieve can be one or both of HY molecular sieve and USY molecular sieve.

[0014] In the preparation method of the modified Y molecular sieve provided by the present invention, the nickel source can be a substance that can provide nickel element for loading, which is common in the art. In some preferred embodiments, the nickel source can be one or more of nitrate, sulfate, chloride and their respective hydrates (the amount of crystal water can be the common amount in the art) of the nickel element. In some more preferred embodiments, the nickel source can be one or more of nickel nitrate, nickel sulfate and their respective hydrates.

[0015] In the preparation method of the modified Y molecular sieve provided by the present invention, the solution of the nickel source can be an aqueous solution of the nickel source, wherein the mass percentage concentration of the nickel source can be 1 to 50%, for example, about 1%, about 2%, about 5%, about 8%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50% or any mass percentage interval. In some preferred embodiments, the mass percentage concentration of the nickel source can be 3 to 30%.

[0016] In the preparation method of the modified Y molecular sieve provided by the present invention, the mass ratio of the unmodified Y molecular sieve to the nickel source can be 10 to 100: 1, for example, about 10: 1, about 20: 1, about 30: 1, about 40: 1, about 50: 1, about 60: 1, about 70: 1, about 80: 1, about 90: 1, about 100: 1 or any mass ratio interval. In some preferred embodiments, the mass ratio of the unmodified Y molecular sieve to the nickel source can be 30 to 60: 1.

[0017] In the preparation method of the modified Y molecular sieve provided by the present invention, the stable element source can be a material that can provide stable elements for loading commonly used in the art. In some preferred embodiments, the stable element source can be one or more of nitrates, sulfates, chlorides and their respective hydrates (the amount of crystal water can be a common amount in the art) of the stable element. In some more preferred embodiments, the stable element source can be one or more of lanthanum nitrate, potassium nitrate, sodium nitrate and their respective hydrates.

[0018] In the preparation method of the modified Y molecular sieve provided by the present invention, the solution of the stabilizing element source can be an aqueous solution of the stabilizing element source, wherein the mass percentage concentration of the stabilizing element source can be 0.1-5%, for example, about 0.1%, about 0.2%, about 0.5%, about 0.8%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5%, about 4%, about 4.5%, about 5% or any mass percentage interval. In some preferred embodiments, the mass percentage concentration of the stabilizing element source can be 0.3-3%.

[0019] In the preparation method of the modified Y molecular sieve provided by the present invention, the mass ratio of the unmodified Y molecular sieve to the stabilizing element source can be 100 to 1000: 1, for example, about 100: 1, about 200: 1, about 300: 1, about 400: 1, about 500: 1, about 600: 1, about 700: 1, about 800: 1, about 900: 1, about 1000: 1 or any mass ratio interval. In some preferred embodiments, the mass ratio of the unmodified Y molecular sieve to the stabilizing element source can be 200 to 600: 1.

[0020] In the preparation method of the modified Y molecular sieve provided by the present invention, the treatment temperature of the first impregnation treatment can be 50-100°C (for example, 60-80°C), the stirring speed can be 100-800r / min (for example, 200-600r / min), and the treatment time can be 5-30h (for example, 5-15h).

[0021] In the preparation method of the modified Y molecular sieve provided by the present invention, the drying temperature in step S1 can be 50-250° C. (for example, 100-200° C.), and the drying time can be 5-50 h (for example, 20-40 h).

[0022] In the preparation method of the modified Y molecular sieve provided by the present invention, the treatment temperature of the second impregnation treatment can be 50-100°C (for example, 60-80°C), the stirring speed can be 100-800r / min (for example, 200-600r / min), and the treatment time can be 10-48h (for example, 10-30h).

[0023] In the preparation method of the modified Y molecular sieve provided by the present invention, the drying temperature in step S2 can be 50-250° C. (for example, 100-180° C.), and the drying time can be 5-50 h (for example, 5-15 h).

[0024] In the preparation method of the modified Y molecular sieve provided by the present invention, the calcination temperature can be 500-800° C. (for example, 550-700° C.), and the calcination time can be 10-48 h (for example, 15-35 h).

[0025] In the preparation method of the modified Y molecular sieve provided by the present invention, the desired material can be obtained through a separation step, for example, separating the loaded molecular sieve wet material after impregnation, and the separation equipment or method can be a common equipment or method in the art, including but not limited to natural sedimentation, (normal pressure or vacuum) filtration, centrifugation and the like and their common equipment.

[0026] The second aspect of the present invention provides a modified Y molecular sieve obtained by the preparation method described in any one of the above technical solutions.

[0027] The third aspect of the present invention provides the use of the modified Y molecular sieve described in any one of the above technical solutions, or the modified Y molecular sieve prepared by the preparation method described in any one of the above technical solutions, in catalyzing the addition reaction of triisobutylene and hydrogen sulfide to prepare tert-dodecyl mercaptan.

[0028] The fourth aspect of the present invention provides a method for preparing tert-dodecyl mercaptan, which comprises: preparing tert-dodecyl mercaptan by an addition reaction using triisobutylene and hydrogen sulfide as raw materials in the presence of a catalyst, wherein the modified Y molecular sieve is the modified Y molecular sieve described in any one of the above technical solutions, or the modified Y molecular sieve obtained by the preparation method described in any one of the above technical solutions.

[0029] In the preparation method of tert-dodecyl mercaptan provided by the present invention, the molar ratio of triisobutylene to hydrogen sulfide can be 1:1-10, for example, about 1:1, about 1:2, about 1:3, about 1:4, about 1:5, about 1:6, about 1:7, about 1:8, about 1:9, about 1:10 or any molar ratio interval. In some preferred embodiments, the molar ratio of triisobutylene to hydrogen sulfide can be 1:3-5.

[0030] In the preparation method of tert-dodecyl mercaptan provided by the present invention, the reaction temperature of triisobutylene and hydrogen sulfide can be 30-100°C, for example, about 30°C, about 40°C, about 50°C, about 60°C, about 70°C, about 80°C, about 90°C, about 100°C or any temperature range. In some preferred embodiments, the reaction temperature of triisobutylene and hydrogen sulfide can be 40-80°C.

[0031] In the preparation method of tert-dodecyl mercaptan provided by the present invention, the reaction pressure of triisobutylene and hydrogen sulfide can be 1-10 MPa, for example, about 1 MPa, about 2 MPa, about 3 MPa, about 4 MPa, about 5 MPa, about 6 MPa, about 7 MPa, about 8 MPa, about 9 MPa, about 10 MPa or any pressure range. In some preferred embodiments, the reaction pressure of triisobutylene and hydrogen sulfide can be 1.2-3 MPa.

[0032] The preparation method of tert-dodecyl mercaptan provided by the present invention can be a batch process or a continuous process. In some preferred embodiments, the preparation method provided by the present invention is a continuous process, which is carried out in a fixed bed catalytic reaction device. For example, a mixture of triisobutylene and hydrogen sulfide is passed into a fixed bed catalytic reaction device filled with a modified Y molecular sieve catalyst for catalytic addition reaction, wherein the feeding method of the mixed material can be an upper feeding method, and the space velocity of triisobutylene can be adjusted according to actual working conditions such as reaction scale and catalyst loading amount. For example, the space velocity of triisobutylene can be 0.5 to 2 h -1 , and further can be 1 to 1.5 hours -1 .

[0033] The technical solution provided by the present invention has the following advantages:

[0034] (1) The present invention has modified the Y molecular sieve with strong acidity and small pore size in many aspects, such as increasing its pore size by calcination, improving the acidity of the molecular sieve by loading nickel elements, and increasing the stability of the nickel elements by loading stabilizing elements. The modified Y molecular sieve thus obtained has a suitable pore size and acidity, and can therefore achieve excellent catalytic activity and stability when used as a catalyst.

[0035] (2) The modified Y molecular sieve provided by the present invention is very suitable for catalyzing the addition reaction of triisobutylene and hydrogen sulfide to prepare tert-dodecyl mercaptan. The conversion rate of the raw material and the selectivity of the target product can be greatly improved. Moreover, the modified Y molecular sieve has good stability, is not easy to deactivate, and has a long service life.

[0036] (3) When the modified Y molecular sieve provided by the present invention catalyzes the addition reaction of triisobutylene and hydrogen sulfide, the reaction can be carried out at a higher reaction temperature, thereby saving refrigeration energy consumption. Moreover, the addition reaction is an exothermic reaction and no additional heating energy consumption is required.

[0037] In summary, the preparation method of the modified Y molecular sieve and tert-dodecyl mercaptan using the modified Y molecular sieve as a catalyst provided by the present invention has simple process, high catalytic efficiency, no high cost, strong industrial applicability, and provides a new direction for the industrial production of tert-dodecyl mercaptan, and therefore has very important economic and social value. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0039] The sources of the raw materials or reagents used in the embodiments and comparative examples of the present invention are as follows:

[0040] HY molecular sieve and USY molecular sieve come from the catalyst factory of Nankai University; triisobutylene comes from Wanhua Chemical with a purity of 99.9%; hydrogen sulfide comes from Dalian Datai Gas with a purity of 99.9%; nickel sulfate and nickel nitrate come from Sinopharm Reagent with reagent grade purity; lanthanum nitrate, potassium nitrate and sodium nitrate come from Sinopharm Reagent with reagent grade purity; other raw materials or reagents are commercially available unless otherwise specified.

[0041] The analytical instruments and analytical methods used in the embodiments and comparative examples of the present invention are as follows:

[0042] Gas chromatograph: Agilent-7820, gas chromatographic column: 0.25mm×30m DB-5 capillary column, detector FID, vaporization chamber temperature 280℃, column box temperature 280℃, FID detector temperature 300℃, argon flow rate 2.1mL / min, hydrogen flow rate 30mL / min, air flow rate 400mL / min, injection volume 1.0μL. Heating program: preheat to column temperature 40℃, hold for 5min, increase from 40℃ to 280℃ at a rate of 15℃ / min, hold for 2min.

[0043] All conversion and selectivity results in the examples and comparative examples of the present invention are chromatographic analysis results, and the TIB conversion and TDM selectivity are calculated using the area normalization method.

[0044] The percentages used in the embodiments and comparative examples of the present invention are all mass percentages unless otherwise specified.

[0045] Example 1

[0046] (1) Catalyst preparation: 300g HY molecular sieve was weighed, and 100ml aqueous solution prepared with 30g nickel sulfate was placed in a beaker, and treated at 70°C and stirring speed of 300r / min for 10h. After the treatment, the obtained material was dried at 150°C and drying time of 30h. Then, the obtained Ni-loaded Y molecular sieve was poured into 100ml aqueous solution prepared with 0.5g lanthanum nitrate, and treated at 70°C and stirring speed of 300r / min for 20h. After the treatment, the obtained material was dried at 120°C and drying time of 9h. After the Y molecular sieve was loaded with Ni and stabilized with La, it was placed in a muffle furnace for calcination at 600°C and calcination time of 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0047] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 82%, and the TDM selectivity was 97%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 78%, and the TDM selectivity was 94%.

[0048] Example 2

[0049] (1) Catalyst preparation: 300g HY molecular sieve was weighed, and 100ml aqueous solution prepared with 10g nickel nitrate was placed in a beaker, and treated at 70°C and stirring speed of 300r / min for 10h. After the treatment, the obtained material was dried at 150°C and drying time of 30h. Then, the prepared Ni-loaded Y molecular sieve was poured into 100ml aqueous solution prepared with 0.5g sodium nitrate, and treated at 70°C and stirring speed of 300r / min for 20h. After the treatment, the obtained material was dried at 120°C and drying time of 9h. After the Y molecular sieve was loaded with Ni and stabilized with Na, it was placed in a muffle furnace for calcination at 600°C and calcination time of 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0050] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1 The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 89%, and the TDM selectivity was 96%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 86%, and the TDM selectivity was 93%.

[0051] Example 3

[0052] (1) Catalyst preparation: 300g USY molecular sieve was weighed, and 100ml aqueous solution prepared with 5g nickel sulfate was placed in a beaker, and treated at 70°C and stirring speed of 300r / min for 10h. After the treatment, the obtained material was dried at 150°C and 30h. Then, the obtained Ni-loaded Y molecular sieve was poured into 100ml aqueous solution prepared with 0.5g potassium nitrate, and treated at 70°C and stirring speed of 300r / min for 20h. After the treatment, the obtained material was dried at 120°C and 9h. After the Y molecular sieve was loaded with Ni and stabilized with K, it was calcined in a muffle furnace at 600°C and 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0053] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 87%, and the TDM selectivity was 94%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 85%, and the TDM selectivity was 92%.

[0054] Example 4

[0055] (1) Catalyst preparation: Weigh 300g USY molecular sieve, place it and 100ml aqueous solution prepared with 3g nickel nitrate in a beaker, treat at 70°C and stirring speed 300r / min for 10h, and dry the obtained material after treatment at 150°C for 30h. Then, pour the obtained Ni-loaded Y molecular sieve into 100ml aqueous solution prepared with 0.5g lanthanum nitrate, treat at 70°C and stirring speed 300r / min for 20h, and dry the obtained material after treatment at 120°C for 9h. After the Y molecular sieve is loaded with Ni and stabilized with La, it is calcined in a muffle furnace at 600°C for 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0056] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1 The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 88%, and the TDM selectivity was 90%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 83%, and the TDM selectivity was 87%.

[0057] Example 5

[0058] (1) Catalyst preparation: 300g HY molecular sieve was weighed, and 100ml aqueous solution prepared with 6g nickel sulfate was placed in a beaker, and treated at 70°C and stirring speed of 300r / min for 10h. After the treatment, the obtained material was dried at 150°C and drying time of 30h. Then, the obtained Ni-loaded Y molecular sieve was poured into 100ml aqueous solution prepared with 3g lanthanum nitrate, and treated at 70°C and stirring speed of 300r / min for 20h. After the treatment, the obtained material was dried at 120°C and drying time of 9h. After the Y molecular sieve was loaded with Ni and stabilized with La, it was placed in a muffle furnace for calcination at 600°C and calcination time of 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0059] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 83%, and the TDM selectivity was 95%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 75%, and the TDM selectivity was 92%.

[0060] Example 6

[0061] (1) Catalyst preparation: 300g HY molecular sieve was weighed, and 100ml aqueous solution prepared with 6g nickel sulfate was placed in a beaker, and treated at 70°C and stirring speed of 300r / min for 10h. After the treatment, the obtained material was dried at 150°C and drying time of 30h. Then, the obtained Ni-loaded Y molecular sieve was poured into 100ml aqueous solution prepared with 1.5g sodium nitrate, and treated at 70°C and stirring speed of 300r / min for 20h. After the treatment, the obtained material was dried at 120°C and drying time of 9h. After the Y molecular sieve was loaded with Ni and stabilized with Na, it was placed in a muffle furnace for calcination at 600°C and calcination time of 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0062] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1 The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 88%, and the TDM selectivity was 94%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 84%, and the TDM selectivity was 93%.

[0063] Example 7

[0064] (1) Catalyst preparation: 300g USY molecular sieve was weighed, and 100ml aqueous solution prepared with 6g nickel sulfate was placed in a beaker, and treated at 70°C and stirring speed of 300r / min for 10h. After the treatment, the obtained material was dried at 150°C and 30h. Then, the obtained Ni-loaded Y molecular sieve was poured into 100ml aqueous solution prepared with 0.5g potassium nitrate, and treated at 70°C and stirring speed of 300r / min for 20h. After the treatment, the obtained material was dried at 120°C and 9h. After the Y molecular sieve was loaded with Ni and stabilized with K, it was calcined in a muffle furnace at 600°C and 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0065] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 88%, and the TDM selectivity was 95%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 85%, and the TDM selectivity was 93%.

[0066] Example 8

[0067] (1) Catalyst preparation: 300g USY molecular sieve was weighed, and 100ml aqueous solution prepared with 6g nickel sulfate was placed in a beaker, and treated at 70°C and stirring speed of 300r / min for 10h. After the treatment, the obtained material was dried at 150°C and 30h. Then, the obtained Ni-loaded Y molecular sieve was poured into 100ml aqueous solution prepared with 0.3g lanthanum nitrate, and treated at 70°C and stirring speed of 300r / min for 20h. After the treatment, the obtained material was dried at 120°C and 9h. After the Y molecular sieve was loaded with Ni and stabilized with La, it was calcined in a muffle furnace at 600°C and 20h, thereby obtaining a modified Y molecular sieve catalyst.

[0068] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1 The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 87%, and the TDM selectivity was 95%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 83%, and the TDM selectivity was 92%.

[0069] Comparative Example 1

[0070] The Y molecular sieve catalyst of Example 1 in KR 20060113045A was used, and the reaction conditions in Example 1 were repeated. Samples were taken after 3 hours of reaction, and the TIB conversion rate was 71%, and the TDM selectivity was 45%. Samples were taken after 3000 hours of continuous operation, and the TIB conversion rate dropped to 8%, and the TDM selectivity was 32%.

[0071] Comparative Example 2

[0072] (1) Catalyst preparation: 300 g of HY molecular sieve was weighed and placed in a beaker with 100 ml of an aqueous solution prepared with 10 g of nickel sulfate. The mixture was treated at 70° C. and a stirring speed of 300 r / min for 10 h. After the treatment, the obtained material was dried at a drying temperature of 150° C. for 30 h. The obtained Ni-loaded Y molecular sieve was calcined in a muffle furnace at a calcination temperature of 600° C. for 20 h to obtain a modified Y molecular sieve catalyst.

[0073] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1 The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 87%, and the TDM selectivity was 93%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 79%, and the TDM selectivity was 90%.

[0074] Comparative Example 3

[0075] (1) Catalyst preparation: 300 g of HY molecular sieve was weighed and poured into 100 ml of an aqueous solution prepared with 1.5 g of sodium nitrate. The mixture was treated at 70° C. and a stirring speed of 300 r / min for 20 h. After the treatment, the obtained material was dried at 120° C. for 9 h. The Y molecular sieve was stabilized with Na and calcined in a muffle furnace at 600° C. for 20 h to obtain a modified Y molecular sieve catalyst.

[0076] (2) Take 100 g of the modified Y molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1 The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 72%, and the TDM selectivity was 47%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 10%, and the TDM selectivity was 33%.

[0077] Comparative Example 4

[0078] (1) Catalyst preparation: Except for not calcining, other steps are the same as those in Example 1.

[0079] (2) Take 100 g of the modified molecular sieve catalyst prepared above and load it into a fixed bed. The feed space velocity of triisobutylene is 1 h -1 The molar ratio of hydrogen sulfide to olefin was 3:1, the reaction temperature was 60°C, the pressure was 2 MPa, and sampling was performed after 3 hours of reaction. The TIB conversion rate was 85%, and the TDM selectivity was 43%. After 3000 hours of continuous operation, sampling was performed after 3 hours of continuous operation. The TIB conversion rate was 9%, and the TDM selectivity was 30%.

[0080] It can be seen from Comparative Example 1 that when the existing Y molecular sieve catalyst reacts at a relatively high temperature, the selectivity of the target product is very low, so the reaction temperature needs to be lowered, the energy consumption is high, the industrial applicability is not strong, and the catalyst is easily deactivated. After a long period of operation, the catalytic activity seriously decreases; it can be seen from Comparative Example 2 that when the molecular sieve is not loaded with a stabilizing element, the initial catalytic activity is basically the same as that in Example 2, but after a long period of operation, the catalytic activity is significantly decreased due to the loss of the Ni element; it can be seen from Comparative Example 3 that when only the stabilizing element is loaded on the molecular sieve, there is no obvious improvement in the catalytic activity, which shows that it can only play a role in assisting the Ni element; it can be seen from Comparative Example 4 that when the molecular sieve is not calcined, the effect of improving the catalytic activity and extending the service life cannot be achieved under a small pore size.

[0081] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0082] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A method for preparing a modified Y molecular sieve, characterized in that: The following steps are involved: S1: performing a first impregnation treatment on the unmodified Y molecular sieve in a nickel source solution, and obtaining a molecular sieve intermediate loaded with nickel after drying; as well as S2: subjecting the molecular sieve intermediate to a second impregnation treatment in a solution of a stabilizing element source, obtaining a Y molecular sieve loaded with nickel and a stabilizing element after drying, and obtaining the modified Y molecular sieve after calcination, wherein the stabilizing element is one or more of lanthanum, sodium, and potassium.

2. The preparation method according to claim 1, characterized in that: The Y molecular sieve is one or both of HY molecular sieve and USY molecular sieve.

3. The preparation method according to claim 1 or 2, characterized in that: The nickel source is one or more of nickel nitrate, sulfate, chloride and their respective hydrates, preferably one or more of nickel nitrate, nickel sulfate and their respective hydrates; Preferably, the mass ratio of the unmodified Y molecular sieve to the nickel source is 10 to 100:1, preferably 30 to 60:

1.

4. The preparation method according to any one of claims 1 to 3, characterized in that The stable element source is one or more of nitrates, sulfates, chlorides and their respective hydrates of the stable element, preferably one or more of lanthanum nitrate, potassium nitrate, sodium nitrate and their respective hydrates; Preferably, the mass ratio of the unmodified Y molecular sieve to the stabilizing element source is 100 to 1000:1, preferably 200 to 600:

1.

5. The preparation method according to any one of claims 1 to 4, characterized in that: The treatment temperature of the first immersion treatment is 50-100° C., the stirring speed is 100-800 r / min, and the treatment time is 5-30 h; and / or The treatment temperature of the second immersion treatment is 50-100° C., the stirring speed is 100-800 r / min, and the treatment time is 10-48 h.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The calcination temperature is 500-800° C. and the calcination time is 10-48 hours.

7. A modified Y molecular sieve, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the modified Y molecular sieve according to claim 7 in catalyzing the addition reaction of triisobutylene and hydrogen sulfide to prepare tert-dodecyl mercaptan.

9. A method for preparing tert-dodecyl mercaptan, characterized in that: In the presence of a catalyst, tert-dodecyl mercaptan is prepared by an addition reaction using triisobutylene and hydrogen sulfide as raw materials, wherein the modified Y molecular sieve is the modified Y molecular sieve according to claim 7.

10. The preparation method according to claim 9, characterized in that: The molar ratio of triisobutylene to hydrogen sulfide is 1:1 to 10, preferably 1:3 to 5; and / or The reaction temperature of triisobutylene and hydrogen sulfide is 30-100° C.; and / or The reaction pressure of triisobutylene and hydrogen sulfide is 1-10 MPa.