Method for preparing Ni base / H beta one-step method for preparing exo-tetrahydrodicyclopentadiene based on precipitation deposition method

Abstract

The invention discloses a method for preparing hanging tetrahydrodicyclopentadiene based on a precipitation-deposition method Ni base / H beta one-step method, which comprises the following steps: S1, preparing a Ni / H beta catalyst by a precipitation-deposition method: dissolving nickel nitrate hexahydrate in deionized water to form a nickel nitrate solution, adding an H beta molecular sieve into the nickel nitrate solution, and dispersing to form a uniform suspension; slowly dropwise adding an ammonia water solution into the suspension, stirring until the pH value reaches 7-11, continuously dropwise adding ammonia water, stirring and keeping the target pH value for half an hour; adding deionized water, stirring and aging at 60 DEG C for 2 hours, and drying at 120 DEG C for 5 hours; grinding into fine powder, roasting at the constant temperature of 500 DEG C for 5 hours, and naturally cooling to room temperature; reducing at 500 DEG C for 4 hours to obtain a Ni / H beta catalyst; s2, one-step hydroisomerization of DCPD: weighing the Ni / H beta catalyst, dicyclopentadiene and ethanol according to a mass ratio of the Ni / H beta catalyst to the dicyclopentadiene to the ethanol of 0.15: 1: 5, and putting the Ni / H beta catalyst, the dicyclopentadiene and the ethanol into a reaction kettle; reacting for 270 minutes under the conditions that the temperature is 170 DEG C, the hydrogen pressure is 3MPa and the stirring speed is 700r / min; and after the reaction is finished, collecting the product and centrifuging by using a centrifugal machine to obtain the hanging type tetrahydrodicyclopentadiene product.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical synthesis, and in particular to a method for preparing exo-tetrahydrodicyclopentadiene based on a one-step method of a precipitation deposition method and a Ni-based / Hβ method. BACKGROUND

[0002] Dicyclopentadiene (DCPD) is mainly derived from the C5 fraction byproduct of ethylene cracking. China is the world's leading producer of DCPD. The global DCPD market size was approximately 6.144 billion yuan in 2023, and is expected to reach 6.336 billion yuan in 2029. Converting DCPD into high-value-added products has become a current research hotspot. Exo-tetrahydrodicyclopentadiene (exo-THDCPD) is a product of DCPD hydrogenation isomerization, with a molecular formula of C 10 H 16 , a molecular weight of 136.23, and a unique "hanging" stereo-bridged structure. It is a spatial isomer of the bridged isomer (endo-THDCPD). It is the core component of US JP-10 fuel (purity needs to be > 98.5%), and is widely used in the propulsion systems of missiles, supersonic aircraft, and rockets. With high density and high thermal stability, it can maintain stable combustion during high-speed flight. Typical application scenarios include fuel supply for Tomahawk cruise missiles.

[0003] Currently, there are two key problems in the technology for preparing exo-THDCPD: Insufficient catalyst performance: The existing method of loading gold on molecular sieves mainly uses impregnation. The metal is prone to agglomeration, resulting in a decrease in active sites. Moreover, Pt-based and other noble metal catalysts are often used, which are high in cost and have limited potential for industrialization. Some studies use Ni-based catalysts, such as loading Ni on NaY and HY molecular sieves. However, the reaction time is as long as 14 hours, and the highest yield of exo-THDCPD is only 24.9% (Ni / LaHY catalyst). Another patent (CN109569632A) discloses a Ni-based catalyst that can only complete the hydrogenation of DCPD to generate endo-THDCPD, and cannot further isomerize to the target product exo-THDCPD.

[0004] High process cost: The traditional process uses a "two-step method", which first hydrogenates DCPD to generate endo-THDCPD, and then separates and purifies the intermediate product before performing isomerization. This requires additional investment in separation equipment such as distillation columns and filters, and has a long operation process, high energy consumption, and increased production costs. SUMMARY

[0005] The present application relates to the technical field of chemical synthesis, and in particular to a method for preparing exo-tetrahydrodicyclopentadiene based on a one-step method of a precipitation deposition method and a Ni-based / Hβ method. The first aspect of the present application provides a method for preparing a Ni-based / Hβ one-step method for preparing a hanging tetrahydrodicyclopentadiene, comprising the following steps: Step 1, preparing a Ni / Hβ catalyst by a precipitation deposition method: dissolving nickel nitrate hexahydrate in deionized water to form a nickel nitrate solution, adding Hβ molecular sieve to the nickel nitrate solution to form a uniform suspension; slowly adding an ammonia solution to the suspension and stirring until the pH value reaches 7-11, continuing to add ammonia and stirring to maintain the target pH value for half an hour; adding deionized water, stirring and aging at 60°C for 2h, drying at 120°C for 5h; grinding to fine powder, baking in a muffle furnace at 500°C at a temperature increase rate of 5°C / min, and naturally cooling to room temperature; reducing at 500°C for 4h to obtain a Ni / Hβ catalyst; Step 2, one-step hydrogenation isomerization of DCPD to prepare a hanging tetrahydrodicyclopentadiene: according to the mass ratio of Ni / Hβ catalyst:dicyclopentadiene:ethanol=0.15:1:5, weighing the Ni / Hβ catalyst, dicyclopentadiene and ethanol and loading them into a reaction kettle; reacting at a temperature of 170°C, a hydrogen pressure of 3MPa and a stirring speed of 700r / min for 270min; after the reaction is completed, collecting the product and centrifuging it with a centrifuge to obtain a hanging tetrahydrodicyclopentadiene product.

[0006] Preferably, in the step of preparing a Ni / Hβ catalyst by a precipitation deposition method, the Hβ molecular sieve is added to the nickel nitrate solution and dispersed by ultrasonic for 30 minutes.

[0007] Preferably, in the step of preparing a Ni / Hβ catalyst by a precipitation deposition method, the ammonia solution is slowly added to the suspension and stirred at a speed of 200-300r / min.

[0008] Preferably, in the step of preparing a Ni / Hβ catalyst by a precipitation deposition method, the ammonia solution is slowly added to the suspension until the pH value reaches 7 or 8 or 9 or 10 or 11.

[0009] Preferably, in the step of preparing a Ni / Hβ catalyst by a precipitation deposition method, after stirring and aging at 60°C for 2h, if the water has not been completely evaporated, the temperature is increased to 80°C until the water and ammonia are completely evaporated.

[0010] Preferably, in the step of preparing a Ni / Hβ catalyst by a precipitation deposition method, after the product is ground to fine powder, it is placed in a muffle furnace and baked at a temperature increase rate of 5°C / min to 500°C.

[0011] Preferably, in the step of preparing a Ni / Hβ catalyst by a precipitation deposition method, a metal additive or a metal oxide additive is also added.

[0012] Preferably, in the step of one-step hydrogenation isomerization of DCPD to prepare a hanging tetrahydrodicyclopentadiene, the mass fraction of the dicyclopentadiene is 0.97.

[0013] A second aspect of the present invention provides a Ni / Hβ catalyst, which is prepared by the precipitation-deposition method described above.

[0014] The third aspect of the present invention provides a hanging tetrahydrodicyclopentadiene, which is prepared by the method described above for a one-step method for preparing hanging tetrahydrodicyclopentadiene based on Ni-based / Hβ precipitation deposition.

[0015] The beneficial effects of this invention are as follows: The one-step hydrogenation isomerization of bridged tetrahydrodicyclopentadiene (exo-THDCPD) using a Ni-based / Hβ catalyst has significant process advantages: thanks to the bifunctional properties of Ni-based / Hβ, the entire process of "dicyclopentadiene (DCPD) hydrogenation → endo-THDCPD isomerization → exo-THDCPD" can be continuously completed in the same reactor without interrupting the reaction to separate intermediate products; it can reduce the equipment and operation costs brought about by the two-step hydrogenation-isomerization process, and save the separation cost of the two-step method of first hydrogenating, separating and purifying the intermediate product bridged tetrahydrodicyclopentadiene, and then isomerizing it to exo, and reduce the investment in equipment such as distillation columns and filters required for the "separation and purification" step. Attached Figure Description

[0016] Figure 1 SEM morphology of Ni / Hβ prepared by the existing impregnation method.

[0017] Figure 2 This is a schematic diagram of the structure of the Ni / Hβ catalyst prepared by the precipitation deposition method at pH=9 according to the present invention.

[0018] Figure 3 The XRD patterns are of Ni / Hβ catalysts prepared by the precipitation deposition method of the present invention based on different pH values.

[0019] Figure 4 The graphs show the adsorption-desorption curves of Ni / Hβ catalysts prepared by the conventional impregnation method and the precipitation-deposition method of this invention.

[0020] Figure 5 The diagram shows the pore size distribution of Ni / Hβ catalysts prepared by the conventional impregnation method and the precipitation deposition method of this invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides a one-step method for preparing Ni-based / Hβ catalysts using a precipitation-deposition method to produce halogenated tetrahydrodicyclopentadiene. The method involves preparing a high-performance Ni-based / Hβ catalyst via precipitation-deposition and then performing a one-step hydroisomerization reaction of DCPD. The specific steps of this method are as follows: S1. Preparation of Ni / Hβ catalyst by precipitation deposition method This step achieves uniform dispersion of Ni by precisely controlling the reaction conditions, thus preventing particle agglomeration. The specific process is as follows: S11. Dissolve nickel nitrate hexahydrate in deionized water to prepare a nickel nitrate solution; add Hβ molecular sieve to the nickel nitrate solution and ultrasonically disperse for 30 minutes to form a uniform suspension; S12. At a stirring speed of 200-300 r / min, slowly add the ammonia solution dropwise to the suspension while monitoring the pH value of the system until the pH reaches 7-11 (preferably pH=8). Continue to add ammonia solution dropwise and stir to maintain the target pH value for half an hour to ensure that Ni²⁺ is fully converted into Ni(OH)₂ and Ni(NH₄)₂. 2+ ; S13. Add deionized water to the system and continue stirring and aging at 60°C for 2 hours to ensure complete precipitation. If the water is not completely evaporated after 2 hours, raise the temperature to 80°C until the water and ammonia are completely evaporated. S14. Place the dried filter cake in a 120℃ oven and dry for 5 hours, then grind it into a fine powder to obtain the NiO / Hβ precursor. S15. The NiO / Hβ precursor was ground into a fine powder and then placed in a muffle furnace for calcination. The temperature was increased to 500℃ at a heating rate of 5℃ / min, and calcined at 500℃ for 5 hours. It was then naturally cooled to room temperature. Finally, it was reduced at 500℃ for 4 hours to obtain a blackish-gray Ni / Hβ catalyst.

[0023] In addition, catalyst performance can be further improved by adding additives: Metal additives: Mo, Co, and Cu are introduced by precipitation deposition to form NiMo, NiCo, and NiCu alloy phases, which enhance hydrogenation activity and metal synergy.

[0024] Metal oxide additives: ZrO2, CeO2 or La2O3 are first loaded onto the Hβ support by precipitation deposition, and then Ni is loaded to introduce Lewis acid sites and increase isomer active sites.

[0025] S2, One-step hydroisomerization DCPD to produce hanging tetrahydrodicyclopentadiene The Ni / Hβ catalyst prepared in step S1 was used for hydrogenation and isomerization reactions, and the specific steps are as follows: S21. Weigh the raw materials according to the mass ratio of Ni / Hβ catalyst: dicyclopentadiene: ethanol = 0.15: 1: 5, wherein the mass fraction of dicyclopentadiene is 0.97. S22. Ni / Hβ catalyst, dicyclopentadiene and ethanol are loaded into a reactor, sealed and hydrogen is introduced. The reaction conditions are controlled as follows: temperature 170℃, hydrogen pressure 3MPa, stirring 700r / min, reaction 270min. S23. After the reaction is complete, the product is collected into a sample bottle and centrifuged to remove catalyst residue, yielding a product containing tetrahydrodicyclopentadiene (exo-THDCPD). The purity can be detected by gas chromatography and the conversion, selectivity and yield can be calculated.

[0026] The technical solution of the present invention will be described in detail below through specific embodiments. All embodiments are based on the above technical solution, only changing the catalyst preparation method, pH value or type of additive, while keeping other conditions the same.

[0027] Example 1: Preparation of Ni / Hβ catalyst (pH=8) by precipitation deposition method Nickel nitrate hexahydrate was dissolved in deionized water, and Hβ molecular sieve was added and ultrasonically dispersed for 30 minutes to form a suspension. The solution was stirred at 200 rpm, and ammonia was added dropwise until the pH reached 8. Ammonia was continued to be added dropwise while stirring to maintain the target pH for half an hour. Deionized water was added to a final volume of 100 ml, and the solution was stirred at 60°C for 2 hours and evaporated to dryness. The solution was then dried at 120°C for 5 hours, ground, and calcined in a muffle furnace at 5°C / min to 500°C for 5 hours, followed by reduction at 500°C for 4 hours to obtain a blackish-gray Ni / Hβ catalyst.

[0028] Comparative Example 1: Preparation of Ni / Hβ catalyst by impregnation method Ni(NO3)2 aqueous solution prepared with 20 ml of deionized water and 10% Ni loading was stirred at room temperature for 2 h to impregnate the support Hβ. The solution was then stirred and heated at 80 °C until the water evaporated, and then dried in an oven at 120 °C for 5 h. The solution was then removed, crushed, and ground. The powder was collected in a quartz beaker and placed in a muffle furnace at 500 °C in air at a heating rate of 5 °C / min for 5 h. After that, it was reduced at a flow rate of 40 mL / min and a temperature of 500 °C for 4 h to obtain a blackish-gray Ni / Hβ catalyst.

[0029] Comparative Example 2: Preparation of Ni / Hβ catalyst by citric acid sol-gel method Nickel nitrate hexahydrate was dissolved in deionized water to obtain solution A. Citric acid was weighed and dissolved in deionized water at a molar ratio of 2:1 to citric acid to obtain solution B. Solution A was slowly added dropwise to solution B with stirring. Hβ molecular sieve was weighed and added to solution B. The mixture was stirred for 1 hour and then evaporated in a 60°C water bath until a viscous sol was formed. After the gel was broken up, it was dried in a 120°C oven for 5 hours to obtain a dry gel precursor. The temperature was increased to 500°C at 5°C / min and kept at that temperature for 5 hours. The temperature was then reduced for 4 hours in an H2 / Ar (10:90) atmosphere at 5°C / min.

[0030] Comparative Example 3: Preparation of Ni / Hβ catalyst by ultrasonic-assisted impregnation method Weigh out nickel nitrate hexahydrate with a 10wt% Ni loading and dissolve it in deionized water. Stir until completely dissolved. Weigh out Hβ molecular sieve and add it to the impregnation solution. Stir and disperse the solution, then treat it with ultrasound at 50kHz frequency and 40℃ water bath for 60 min. Then, place it in an oven at 120℃ for 5 h, increase the temperature at 5℃ / min to 500℃ and hold for 5 h for calcination. Then, reduce the temperature in an H2 / Ar (10:90) atmosphere at 5℃ / min to 500℃ and reduce for 4 h.

[0031] Example 2: One-step hydroisomerization reaction (using the catalyst from Example 1) 1.5 g of Ni / Hβ catalyst from Example 1 and Comparative Examples 1 to 3, 10 g of DCPD (0.97% by mass), and 50 g of ethanol were weighed and separately assembled into a reaction vessel for reaction. The temperature was controlled at 170 °C, the hydrogen pressure at 3 MPa, and the stirring speed at 700 r / min, and the reaction was carried out for 270 minutes. After the reaction was completed, the product was collected into a sample bottle and centrifuged to obtain a product containing tetrahydrodicyclopentadiene (exo-THDCPD). The purity of the product was detected by gas chromatography after centrifugation, and the conversion rate and yield of the reaction were calculated. The calculation results are shown in Table 1 below.

[0032] Table 1 Experimental group Ni / Hβ catalyst preparation method DCPD conversion rate / % exo-THDCPD yield / % Comparative example 1 Immersion method 100 9.2 Comparative example 2 Citric acid sol-gel method 100 8.5 Comparative example 3 Ultrasonic immersion method 100 5.2 Example 1 Precipitation deposition method (pH = 8) 100 28.7 Results Analysis: As shown in Table 1 above, the yields of exo-THDCPD varied significantly among different preparation methods, ranked from highest to lowest as follows: precipitation deposition method (pH=8) (28.7%) > impregnation method (9.2%) > citric acid sol-gel method (8.5%) > ultrasonic impregnation method (5.2%). This indicates that, under the premise of complete DCPD conversion, the precipitation deposition method (pH=8) is the most favorable preparation method for exo-THDCPD formation, with a yield more than 5.5 times that of the ultrasonic impregnation method.

[0033] Example 3: Comparison of catalyst performance at different pH values Following the method of Example 1, Ni / Hβ catalysts with pH values ​​of 7, 9, 10, and 11 were prepared and subjected to a one-step reaction. The purity of the products containing tetrahydrodicyclopentadiene (exo-THDCPD) prepared using the Ni / Hβ catalysts of this example and Example 1 was detected by gas chromatography. The conversion rate and yield of the reaction were calculated, and the calculation results are shown in Table 2 below.

[0034] Table 2 Experimental group Ni / Hβ catalyst preparation method DCPD conversion rate / % exo-THDCPD yield / % Example 3 Precipitation deposition method (pH = 7) 100 27.4 Example 1 Precipitation deposition method (pH = 8) 100 28.7 Example 3 Precipitation deposition method (pH = 9) 100 23.4 Example 3 Precipitation deposition method (pH = 10) 100 23.5 Example 3 Precipitation deposition method (pH = 11) 100 24.9 Results Analysis: As shown in Table 1 above, the Ni / Hβ catalyst prepared at pH=8 has a significantly higher exo-THDCPD yield than other pH values ​​while maintaining complete DCPD conversion (100% conversion rate). Therefore, pH=8 is the optimal pH value for preparing Ni / Hβ catalyst by precipitation deposition method.

[0035] To further investigate the effects of metal additives and metal oxide additives on catalyst performance, this invention conducts experiments in several embodiments based on the precipitation deposition method of Example 1 and the one-step hydroisomerization reaction of Example 2.

[0036] Example 4: Preparation of ZrO2 / Hβ catalyst by precipitation deposition method Zirconium nitrate pentahydrate was dissolved in deionized water. Hβ molecular sieves were added to the zirconium nitrate solution and ultrasonically dispersed for 30 minutes to form a homogeneous suspension. While stirring (200-300 rpm), ammonia solution was slowly added dropwise to the suspension, with the pH monitored until it reached approximately 8. Ammonia was continued to be added dropwise while stirring to maintain the target pH for half an hour. After the addition was complete, deionized water was added to 100 ml, and the mixture was stirred and aged at 60°C for 2 hours to ensure complete precipitation. After 40 minutes, the water was to be evaporated. If not evaporated completely after 2 hours, the temperature was raised to 80°C to evaporate the water and ammonia. The filter cake was then placed in an oven and dried at 120°C for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and calcined at 500°C at a rate of 5°C / min for 5 hours, then allowed to cool naturally to room temperature.

[0037] Example 5: Preparation of NiZrO2 / Hβ catalyst by precipitation deposition method Nickel nitrate hexahydrate was dissolved in deionized water. The ZrO2 / Hβ prepared in Example 4 was added to the nickel nitrate solution, where Ni and ZrO2 accounted for 10% and 5% of the catalyst mass fraction, respectively. The solution was ultrasonically dispersed for 30 minutes to form a uniform suspension. Under stirring (200-300 rpm), ammonia solution was slowly added dropwise to the suspension, while monitoring the pH value to around 8. The ammonia solution was added dropwise and stirred to maintain the target pH value for half an hour. After the addition was complete, deionized water was added to 100 ml. The mixture was stirred and aged at 60 degrees Celsius for 2 hours to ensure complete precipitation. After 40 minutes, the water was to be evaporated. If it was not evaporated after 2 hours, the temperature was raised to 80 degrees Celsius to evaporate the water and ammonia solution. The filter cake was then placed in an oven and dried at 120 degrees Celsius for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and heated to 500°C at 5°C / min. It was then calcined at a constant temperature for 5 hours and allowed to cool naturally to room temperature. The sample was then reduced in a tube furnace under an H2 / Ar (10:90) atmosphere at 5°C / min to 500°C for 4 hours.

[0038] Example 6: Preparation of CeO2 / Hβ catalyst by precipitation deposition method Cerium nitrate hexahydrate was dissolved in deionized water. Hβ molecular sieves were added to the cerium nitrate solution and ultrasonically dispersed for 30 minutes to form a homogeneous suspension. While stirring (200-300 rpm), ammonia solution was slowly added dropwise to the suspension, with the pH monitored until it reached approximately 8. Ammonia was continued to be added dropwise while stirring to maintain the target pH for half an hour. After the addition was complete, deionized water was added to 100 ml, and the mixture was stirred and aged at 60°C for 2 hours to ensure complete precipitation. After 40 minutes, the water was to be evaporated. If not evaporated completely after 2 hours, the temperature was raised to 80°C to evaporate the water and ammonia. The filter cake was then placed in an oven and dried at 120°C for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and calcined at 500°C at a rate of 5°C / min for 5 hours, then allowed to cool naturally to room temperature.

[0039] Example 7: Preparation of NiCeO2 / Hβ catalyst by precipitation deposition method Weigh out nickel nitrate hexahydrate into deionized water and stir until completely dissolved. Add the CeO2 / Hβ prepared in Example 6 to the nickel nitrate solution and sonicate for 30 minutes to form a uniform suspension. Under stirring (200-300 rpm), slowly add ammonia solution dropwise to the suspension while monitoring the pH value to around 8. Continue adding ammonia solution dropwise and stirring to maintain the target pH value for half an hour. After the addition is complete, add deionized water to 100 ml and continue stirring at 60 degrees Celsius for aging to ensure complete precipitation. After 40 minutes, when the water is about to evaporate, if it is not evaporated after 2 hours, raise the temperature to 80 degrees Celsius to evaporate the water and ammonia solution. Then place the filter cake in an oven and dry it in a 120 degrees Celsius oven for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and heated to 500°C at 5°C / min. It was then calcined at a constant temperature for 5 hours and allowed to cool naturally to room temperature. The sample was then reduced in a tube furnace under an H2 / Ar (10:90) atmosphere at 5°C / min to 500°C for 4 hours.

[0040] Example 8: Preparation of La2O3 / Hβ catalyst by precipitation-deposition method Weigh out lanthanum nitrate hexahydrate into deionized water and stir until completely dissolved. Add Hβ molecular sieve to the lanthanum nitrate solution and sonicate for 30 minutes to form a homogeneous suspension. Under stirring (200-300 rpm), slowly add ammonia solution dropwise to the suspension while monitoring the pH to around 7. Continue adding ammonia solution and stirring to maintain the target pH for half an hour. After the addition is complete, add deionized water to 100 ml and continue stirring at 60°C for aging to ensure complete precipitation. After 40 minutes, the water should be evaporated. If it is not evaporated after 2 hours, raise the temperature to 80°C to evaporate the water and ammonia solution. Place the filter cake in an oven and dry it at 120°C for 5 hours. Grind the calcined product into a fine powder. Place the dried sample in a muffle furnace and calcine at 500°C at a rate of 5°C / min for 5 hours. Allow it to cool naturally to room temperature.

[0041] Example 9: Preparation of NiLa2O3 / Hβ catalyst by precipitation deposition method Weigh out nickel nitrate hexahydrate into deionized water and stir until completely dissolved. Add the La2O3 / Hβ prepared in Example 8 to the nickel nitrate solution and sonicate for 30 minutes to form a uniform suspension. Under stirring (200-300 rpm), slowly add ammonia solution dropwise to the suspension while monitoring the pH value to around 8. Continue adding ammonia solution dropwise and stirring to maintain the target pH value for half an hour. After the addition is complete, add deionized water to 100 ml and continue stirring at 60 degrees Celsius for 2 hours to ensure complete precipitation. After 40 minutes, when the water is about to evaporate, if it is not evaporated after 2 hours, raise the temperature to 80 degrees Celsius to evaporate the water and ammonia solution. Then place the filter cake in an oven and dry it in a 120 degrees Celsius oven for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and heated to 500°C at 5°C / min. It was then calcined at a constant temperature for 5 hours and allowed to cool naturally to room temperature. The sample was then reduced in a tube furnace under an H2 / Ar (10:90) atmosphere at 5°C / min to 500°C for 4 hours.

[0042] Example 10: Preparation of NiMo / Hβ catalyst by precipitation deposition method Weigh ammonium molybdate and add it to deionized water, heating and stirring at 40°C until completely dissolved. Weigh nickel nitrate hexahydrate and add it to deionized water, stirring until completely dissolved. Pour the nickel nitrate solution into the ammonium molybdate solution, then add Hβ molecular sieve to the mixed solution of ammonium molybdate and nickel nitrate. Under stirring (200-300 rpm), slowly add ammonia solution dropwise to the suspension, while monitoring the pH value to around 8. Continue adding ammonia solution dropwise and stirring to maintain the target pH value for half an hour. After the addition is complete, add deionized water to 100 ml, continue stirring at 60°C for aging for 2 hours to ensure complete precipitation. After 40 minutes, when the water is about to evaporate, if it is not evaporated after 2 hours, raise the temperature to 80°C to evaporate the water and ammonia solution. Then place the filter cake in an oven and dry it in a 120°C oven for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and heated to 500°C at 5°C / min. It was then calcined at a constant temperature for 5 hours and allowed to cool naturally to room temperature. The sample was then reduced in a tube furnace under an H2 / Ar (10:90) atmosphere at 5°C / min to 500°C for 4 hours.

[0043] Example 11: Preparation of NiCo / Hβ catalyst by precipitation deposition method Weigh out cobalt nitrate hexahydrate and nickel nitrate hexahydrate and add them to deionized water, stirring until completely dissolved. Add Hβ molecular sieve to the mixed solution of cobalt nitrate and nickel nitrate, and sonicate for 30 minutes to form a uniform suspension. Under stirring (200-300 rpm), slowly add ammonia solution dropwise to the suspension, while monitoring the pH value to around 8. Continue adding ammonia solution dropwise and stirring to maintain the target pH value for half an hour. After the addition is complete, add deionized water to 100 ml, and continue stirring at 60 degrees Celsius for aging to ensure complete precipitation. After 40 minutes, when the water is about to evaporate completely, if it is not evaporated completely after 2 hours, raise the temperature to 80 degrees Celsius to evaporate the water and ammonia solution. Then place the filter cake in an oven and dry it in a 120 degrees Celsius oven for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and heated to 500°C at 5°C / min. It was then calcined at a constant temperature for 5 hours and allowed to cool naturally to room temperature. The sample was then reduced in a tube furnace under an H2 / Ar (10:90) atmosphere at 5°C / min to 500°C for 4 hours.

[0044] Example 12: Preparation of NiCu / Hβ catalyst by precipitation deposition method Weigh out copper nitrate trihydrate and nickel nitrate hexahydrate and add them to deionized water, stirring until completely dissolved. Add Hβ molecular sieve to the lanthanum nitrate solution and sonicate for 30 minutes to form a uniform suspension. Under stirring (200-300 rpm), slowly add ammonia solution dropwise to the suspension, monitoring the pH value until it reaches approximately 8. Continue adding ammonia solution dropwise while stirring to maintain the target pH value for half an hour. After the addition is complete, add deionized water to 100 ml and continue stirring at 60 degrees Celsius for aging to ensure complete precipitation. After 40 minutes, the water should be evaporated. If it is not evaporated completely after 2 hours, raise the temperature to 80 degrees Celsius to evaporate the water and ammonia solution. Then, place the filter cake in an oven and dry it at 120 degrees Celsius for 5 hours. The calcined product was ground into a fine powder. The dried sample was placed in a muffle furnace and heated to 500°C at 5°C / min. It was then calcined at a constant temperature for 5 hours and allowed to cool naturally to room temperature. The sample was then reduced in a tube furnace under an H2 / Ar (10:90) atmosphere at 5°C / min to 500°C for 4 hours.

[0045] Example 13: One-step hydrogenation isomerization DCPD of Ni-based / Hβ to produce hanging tetrahydrodicyclopentadiene To facilitate the preparation of Ni-based / Hβ catalysts and dicyclopentadiene dissolved in ethanol, prepared in Examples 5, 7, and 9 to 12, the Ni-based / Hβ catalysts were assembled in a reaction vessel with a ratio of Ni-based / Hβ: dicyclopentadiene: ethanol of 0.15:1:5. 10 g of dicyclopentadiene with a mass fraction of 0.97, 1.5 g of Ni-based / Hβ catalyst, and 50 g of solvent were weighed. The reaction was carried out at 170°C, 3 MPa, for 270 min, and stirred at 700 r / min. After the reaction was completed, the product was collected in a sample bottle and centrifuged. The purity of the product was detected by gas chromatography, and the conversion rate, selectivity, and yield of the reaction were calculated.

[0046] The product data obtained in Examples 5, 7, 9 to 12 were calculated and compared, and the results are shown in Table 3 below.

[0047] Table 3

[0048] Results Analysis: As can be seen from the above examples, after adding metal promoters Mo, Co, Cu and metal oxide promoters ZrO2, CeO2, and La2O3 respectively, the hydrogenation conversion rate of Ni-based / catalyst remains at 100%, and it maintains a certain degree of isomerism activity. Introducing the interaction force between metallic Ni and metal or metal oxide can reduce the interaction force between Ni and the support, and prevent Ni from combining with the free aluminum species that are released from the Hβ molecular sieve at high temperature, thereby affecting the hydrogenation activity of Ni and the isomerism activity of Hβ molecular sieve.

[0049] To investigate the influence of the preparation method on the catalyst's morphology, pore size, and other microstructures, the Ni / Hβ catalyst prepared by the impregnation method was subjected to SEM analysis. The results are as follows: Figure 1 As shown in the electron microscopy analysis, it can be found that the catalyst supported by Ni by impregnation has a large number of clusters, with the clusters generally ranging from 50 nm to 100 nm. The molecular sieve support has a good morphology, but the agglomeration phenomenon is more serious and it is easy to cause pore blockage.

[0050] Simultaneously, this invention also performs morphology and Ni dispersion analysis on the Ni / Hβ catalyst prepared under precipitation conditions at pH=9, such as... Figure 2 As shown, (a) is the SEM morphology image, (b) is the EDS energy dispersive spectroscopy (EDS) image, (c) is the Al spectrum, (d) is the Ni spectrum, (e) is the O spectrum, and (f) is the Si spectrum. In the EDS energy dispersive spectroscopy (b), it can be observed that compared to the impregnation method, the Ni-loaded catalyst formed by the precipitation deposition method has smaller and fewer clusters, with a size less than 50 nm. Furthermore, the Ni distribution shown in the EDS is more uniform. Using the precipitation deposition method to load Ni reduces particle aggregation and pore blockage, improves the accessibility of acidic sites, and enhances the catalyst's hydroisomerization activity.

[0051] In addition, the present invention also provides XRD patterns of Ni / Hβ catalysts prepared under precipitation conditions of pH=7, 8, 9, 10, and 11 (see [reference]). Figure 3 Adsorption-desorption curves (see) Figure 4 Aperture distribution map (see) Figure 5 The specific surface area, pore volume, and pore diameter were analyzed using a comparison table (see Table 4).

[0052] like Figure 3As shown, compared with the Ni / Hβ molecular sieve prepared by impregnation method, the NiO=37.249°(111) peak in the prepared catalyst completely disappeared, indicating that under the same H2 reduction conditions, Ni loaded by precipitation deposition method is more easily reduced, and it is not necessary to use excessively high temperature to prepare Ni / Hβ, thus avoiding further high-temperature sintering of Ni.

[0053] Table 4. Comparison of specific surface area, pore volume, and pore size of Ni / Hβ catalysts prepared by impregnation and precipitation-deposition methods. Sample Specific surface area (m2 / g) Micropore volume (ml / g) Pore volume (ml / g) Pore size (nm) Ni / Hβ (immersion method) 394.6598 0.1381 0.5418 5.4913 Ni / Hβ (precipitation deposition method pH = 7) 497.6502 0.1776 0.3373 2.7111 Ni / Hβ (precipitation deposition method pH = 8) 518.5853 0.1525 0.3935 3.0352 Ni / Hβ (precipitation deposition method pH = 9) 555.2475 0.1508 0.4546 3.2879 Ni / Hβ (precipitation deposition method pH = 10) 506.1454 0.1313 0.4211 3.3279 Ni / Hβ (precipitation deposition method pH = 11) 569.9188 0.1321 0.5164 3.6244 like Figure 4 As shown in Table 4, the Ni / Hβ molecular sieve supported by the precipitation deposition method conforms to the type IV isotherm, forming an H3 hysteresis loop in the range of 0.4-0.9, exhibiting a large number of mesopores and micropores, and a decrease in average pore size, indicating the formation of some new micropores and mesopores. After the nickel-ammonia complex and nickel hydroxide settle in the molecular sieve channels, they decompose during drying, releasing ammonia gas, resulting in new micropores and mesopores. This leads to a larger specific surface area compared to the catalyst supported by the impregnation method for Ni, and also indirectly indicates that smaller metal clusters are beneficial in reducing the clogging of micropores and mesopores, thus having a gain effect on the specific surface area.

[0054] As can be seen from the above embodiments, the beneficial effects of the present invention are as follows: In terms of preparation methods, compared with traditional impregnation, citric acid sol-gel method, and ultrasonic-assisted impregnation method, precipitation deposition method is the optimal method for preparing highly active Ni-based / Hβ catalysts. Ammonia is used as the precipitant, and Ni(OH)₂ and Ni(NH₄)₂ are formed during the dropwise addition process. 2+ The complex and the two components inhibit the migration and aggregation of Ni particles through steric hindrance. During subsequent drying (120℃) and calcination (500℃), ammonia and water vapor escape, which on the one hand promotes the precipitation and dispersion of Ni into small clusters (<50nm), and on the other hand forms new mesopores in the Hβ channels, while retaining the three-dimensional twelve-membered ring micropores (0.56-0.75nm) of Hβ itself, which is suitable for the internal diffusion requirements of DCPD molecular size (C10 framework). SEM characterization shows that the Ni / Hβ cluster size prepared by the impregnation method is 50-100nm, with severe aggregation (easily clogging the channels); while the clusters prepared by the precipitation deposition method are <50nm and uniformly dispersed. XRD characterization shows that the characteristic peak of NiO (37.249°, 111 crystal plane) in the catalyst prepared by the precipitation deposition method completely disappears, indicating that Ni is more easily reduced by H2 (no high-temperature sintering is required, avoiding Ni particle growth). Adsorption-desorption curves show that the product from the precipitation deposition method conforms to the type IV isotherm, and an H3 hysteresis loop appears in the 0.4-0.9P / P0 range, proving the existence of a "microporous + mesoporous" composite structure. The specific surface area is significantly higher than that of the impregnation method, reducing mass transfer resistance and making it easier for the DCPD to contact the Ni hydrogenation active sites and Hβ acidic sites within the pores.

[0055] Regarding pH value, the experiment explored the effects of pH=7, 8, 9, 10, and 11 on catalyst performance. pH=8 was the optimal value, its advantage stemming from the synergistic effect of pH-precipitation morphology-acidity site compatibility: When pH is too low, ammonia is insufficient, Ni... 2+ Ni(OH)2 or Ni(NH4)2 cannot be completely formed 2+ This leads to insufficient Ni loading and a reduction in hydrogenation active sites. Excessive ammonia at high pH promotes excessive growth of Ni(OH)₂ precipitate, forming large particle agglomerates; simultaneously, high concentrations of OH... - It may bind to Al in the Hβ backbone, disrupting its BEA structure, weakening acidic sites (especially Brønsted acids), and reducing isomerization activity. Ni can be achieved at pH=8. 2+ The catalyst is completely precipitated and morphologically stable, ensuring uniform Ni dispersion (sufficient hydrogenation sites) without disrupting the pore structure and acidic sites of Hβ, thus providing a suitable bifunctional environment for the continuous hydrogenation-isomerization reaction. In Example 10, the exo-THDCPD yield of the precipitation-deposition catalyst at pH=8 was significantly higher than that of other pH groups under conditions of 170°C and 3 MPa, demonstrating that the hydrogenation activity and isomerization activity reach optimal balance under these conditions.

[0056] Even after adding metal and metal oxide additives, the hydrogenation conversion rate of Ni-based catalysts remains at 100%, and it also maintains a certain degree of isomerism activity. Introducing the interaction force between metallic Ni and metal or metal oxide can reduce the interaction force between Ni and the support, and prevent Ni from combining with free aluminum species that have detached from the Hβ molecular sieve at high temperature, thereby affecting the hydrogenation activity of Ni and the isomerism activity of the Hβ molecular sieve.

[0057] Compared to the traditional two-step method, this invention offers significant advantages for the one-step hydrogenation isomerization of bridged tetrahydrodicyclopentadiene (exo-THDCPD) using a Ni-based / Hβ catalyst. Leveraging the dual-functionality of Ni-based / Hβ, the entire process of "dicyclopentadiene (DCPD) hydrogenation → endo-THDCPD isomerization → exo-THDCPD" can be completed continuously within the same reactor without interrupting the reaction to separate intermediate products. This reduces equipment and operational costs associated with the two-step hydrogenation-isomerization process, and saves on the separation costs associated with the two-step method of first hydrogenating, separating and purifying the intermediate product bridged tetrahydrodicyclopentadiene, and then isomerizing it to exo. It also reduces the investment in equipment such as distillation columns and filters required for the "separation and purification" stage.

[0058] Based on the same inventive concept as the above-described method for preparing Ni-based / Hβ in a one-step process using precipitation deposition to prepare suspended tetrahydrodicyclopentadiene, this invention also provides a Ni / Hβ catalyst, which is prepared using the above-described precipitation deposition method for preparing Ni / Hβ catalysts.

[0059] Based on the same inventive concept as the above-mentioned method for preparing Ni-based / Hβ one-step preparation of hanging tetrahydrodicyclopentadiene using precipitation deposition, the present invention also provides hanging tetrahydrodicyclopentadiene, which is prepared by the above-mentioned method for preparing Ni-based / Hβ one-step preparation of hanging tetrahydrodicyclopentadiene using precipitation deposition.

[0060] Regarding the embodiments of the present invention, it should also be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other to obtain new embodiments.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. The scope of protection of the present invention should be determined by the scope of the claims. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. Process for the preparation of Ni-based / Hβ one-step process for the preparation of the hanging tetrahydrodicyclopentadiene based on the precipitated deposition method, characterized in that, The method comprises the following steps: The Ni / Hβ catalyst is prepared by a precipitation deposition method: nickel nitrate hexahydrate is dissolved in deionized water to form a nickel nitrate solution, and Hβ molecular sieve is added into the nickel nitrate solution to form a uniform suspension; ammonia water solution is slowly added into the suspension and stirred until the pH value reaches 7-11, and the ammonia water is continuously added and stirred for half an hour to maintain the target pH value; deionized water is added, and the mixture is stirred and aged at 60 ℃ for 2 hours, and then dried at 120 ℃ for 5 hours; the product is ground into fine powder and calcined at 500 ℃ for 5 hours, and then naturally cooled to room temperature; the product is reduced at 500 ℃ for 4 hours to obtain the Ni / Hβ catalyst; The method comprises the following steps:

2. The process for the preparation of Ni-based / Hβ one-step method for the preparation of tetrahydrodicyclopentadiene according to claim 1, characterized by, In the step of preparing the Ni / Hβ catalyst by the precipitation deposition method, the Hβ molecular sieve is added into the nickel nitrate solution and dispersed by ultrasonic for 30 minutes.

3. The process for the preparation of Ni-based / Hβ one-step method for the preparation of tetrahydrodicyclopentadiene according to claim 1, characterized by that, In the step of preparing the Ni / Hβ catalyst by the precipitation deposition method, the ammonia water solution is slowly added into the suspension and stirred at a speed of 200-300 r / min.

4. The process for the preparation of Ni-based / Hβ one-step method for the preparation of tetrahydrodicyclopentadiene according to claim 1, characterized by that, In the step of preparing the Ni / Hβ catalyst by the precipitation deposition method, the ammonia water solution is slowly added into the suspension until the pH value reaches 7 or 8 or 9 or 10 or 11.

5. The process for the preparation of Ni-based / hanging tetrahydrodicyclopentadiene by precipitation deposition method according to claim 1, characterized by, In the step of preparing the Ni / Hβ catalyst by the precipitation deposition method, after the mixture is stirred and aged at 60 ℃ for 2 hours, if the water is not completely evaporated, the temperature is increased to 80 ℃ until the water and ammonia water are completely evaporated.

6. The process for the preparation of Ni-based / hanging tetrahydrodicyclopentadiene by precipitation deposition method according to claim 1, characterized by, In the step of preparing the Ni / Hβ catalyst by the precipitation deposition method, after the product is ground into fine powder, the product is placed in a muffle furnace and calcined at a temperature increasing rate of 5 ℃ / min to 500 ℃.

7. The process for the preparation of Ni-based / hanging tetrahydrodicyclopentadiene by precipitation deposition method according to claim 1, characterized by that, In the step of preparing the Ni / Hβ catalyst by the precipitation deposition method, a metal additive or a metal oxide additive is further added.

8. The process for the preparation of Ni-based / hanging tetrahydrodicyclopentadiene by precipitation deposition method according to claim 1, characterized by, In the step of preparing the exo-tetrahydrodicyclopentadiene by one-step hydrogenation isomerization of DCPD, the mass fraction of the dicyclopentadiene is 0.

97.

9. A Ni / Hβ catalyst characterized in that, The exo-tetrahydrodicyclopentadiene is prepared by the method for preparing the exo-tetrahydrodicyclopentadiene by one-step hydrogenation isomerization of DCPD based on the precipitation deposition method for preparing the Ni / Hβ catalyst.

10. A pendant tetrahydrodicyclopentadiene characterized by, The exo-tetrahydrodicyclopentadiene is prepared by the method for preparing the exo-tetrahydrodicyclopentadiene by one-step hydrogenation isomerization of DCPD based on the precipitation deposition method for preparing the Ni / Hβ catalyst.

Images