A flat plate-shaped zsm-5 supported metal palladium catalyst, a preparation method and application thereof
By preparing a plate-shaped ZSM-5 supported palladium catalyst, the problems of low selectivity and low activity of polycyclic aromatic hydrocarbon (PAH) hydrogenation catalysts were solved, achieving efficient PAH conversion, reducing catalyst costs, and expanding its industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-11
- Publication Date
- 2026-03-27
AI Technical Summary
Existing polycyclic aromatic hydrocarbon hydrogenation catalysts suffer from poor selectivity and low catalytic activity. Furthermore, the synthesis cost of thin-plate ZSM-5 molecular sieves is high and they are not environmentally friendly, which limits their large-scale industrial application.
A simple and easy method was used to synthesize a plate-shaped ZSM-5 supported palladium catalyst. The growth of the b-axis of the molecular sieve was controlled by adjusting the proportion of ammonium fluoride solution, and a ZSM-5 molecular sieve support with a b-axis length of 50-60 nm was prepared and loaded with 0.1-2.0 wt% active palladium metal for use in the hydrogenation reaction of polycyclic aromatic hydrocarbons.
It improves the activity and selectivity of the catalyst, with a maximum naphthalene conversion rate of 51.33% and a acenaphthene conversion rate of 95.83%, while reducing the cost of the catalyst and showing good application prospects.
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Figure CN118976533B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metal palladium catalyst and polycyclic aromatic hydrocarbon catalytic hydrogenation, and particularly relates to a flat-plate ZSM-5 supported metal palladium catalyst and a preparation method and application thereof. BACKGROUND
[0002] Polycyclic aromatic hydrocarbons refer to a kind of carbon hydrogen compounds including naphthalene series double-ring aromatic hydrocarbons, anthracene, phenanthrene series three-ring aromatic hydrocarbons. Naphthalene oil is a separation product of 200-230 DEG C fraction in coal tar, and 80-85% of naphthalene in coal tar exists in the naphthalene oil fraction. Naphthalene and acenaphthene are main compounds in naphthalene oil, and selective hydrogenation conversion of the naphthalene oil into tetrahydronaphthalene, decahydronaphthalene, tetrahydroacenaphthene, decahydroacenaphthene and other high-value-added chemicals can greatly improve the utilization value of coal tar. At present, the catalysts for polycyclic aromatic hydrocarbon hydrogenation treatment have the defects of poor selectivity and low catalytic activity. Therefore, the development of high-activity and high-selectivity hydrogenation catalysts has become a key step for polycyclic aromatic hydrocarbon hydrogenation conversion.
[0003] In recent years, different ways have been adopted to promote the accessibility and diffusion efficiency of ZSM-5 molecular sieve, generally by modifying the morphology and structure of the molecular sieve crystals, such as reducing the crystals to nanometer size, introducing mesopores into the zeolite structure, reducing the thickness of the crystals along a special diffusion path, etc. Among them, shortening the b-axis thickness of ZSM-5 crystals, i.e. reducing the diffusion path of the reactants, has attracted much attention. The key milestone is the preparation of thin-plate ZSM-5 nanosheets developed by Ryoo et al. However, the synthesis of ZSM-5 molecular sieve nanosheets is hindered by high cost, environmental unfriendliness and complex organic structure directing agents (SDAs), etc., which hinders its wide application, especially limiting its large-scale application in actual industry. Therefore, it is a promising research to obtain such thin-plate ZSM-5 zeolite using a synthesis system with readily available raw materials and easy operation. SUMMARY
[0004] The first object of the present application is to provide a preparation method of a flat-plate ZSM-5 supported metal palladium catalyst, which has simple steps and can greatly reduce the Pd dosage and catalyst cost.
[0005] The second object of the present application is to provide a flat-plate ZSM-5 supported metal palladium catalyst prepared by the above preparation method.
[0006] The third object of the present application is to provide the application of the above flat-plate ZSM-5 supported metal palladium catalyst.
[0007] To achieve the above objects, the technical solutions adopted by the present application are as follows:
[0008] In a first aspect, the present application provides a preparation method of a flat-plate ZSM-5 supported metal palladium catalyst, comprising the following steps:
[0009] (1) mixing the silicon source, deionized water and template agent at room temperature, stirring until a transparent synthesis gel is obtained, the molar composition of which is SiO2 / template agent = 1:0.35;
[0010] (2) adding an aluminum source to the gel obtained in step (1) and stirring at 90°C for 12h; the amount of aluminum source added is kept at nSiO2 / nAl2O3 = 1:(0.01-0.04);
[0011] (3) dissolving ammonium fluoride (NH4F) in deionized water, slowly adding it to the gel obtained in step (2) after ultrasonic treatment, and stirring vigorously for 12h; the amount of ammonium fluoride added is kept at nSiO2 / nNH4F = 1:(0.1-1.0);
[0012] (4) hydrothermally crystallizing the gel obtained in step (3), after the crystallization reaction is completed, the product obtained is washed with deionized water until it is neutral, and then dried to obtain a molecular sieve solid powder;
[0013] (5) grinding the molecular sieve solid powder obtained, and calcining to remove the template agent, thereby obtaining a flat plate-shaped ZSM-5 molecular sieve carrier;
[0014] (6) dissolving palladium acetate in dichloromethane, adding the flat plate-shaped ZSM-5 molecular sieve carrier to it after ultrasonic treatment, stirring vigorously for 3h, and standing at room temperature for 24h; then, drying, calcining and reducing to obtain a flat plate-shaped ZSM-5 supported metal palladium (Pd) catalyst.
[0015] Preferably, the silicon source is selected from at least one of tetraethyl orthosilicate (TEOS), silica sol, water glass, white carbon black and solid silica gel.
[0016] Preferably, the template agent is selected from at least one of tetrapropylammonium hydroxide (TPAOH), tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrapropylammonium hydroxide.
[0017] Preferably, the aluminum source is selected from at least one of pseudo-boehmite (PB), sodium metaaluminate (NaAlO2), aluminum sulfate, aluminum chloride, aluminum nitrate and aluminum isopropylate.
[0018] Preferably, the temperature of the crystallization in step (4) is 160°C, and the crystallization time is 72h.
[0019] Preferably, the temperature of the calcination in step (5) is 550°C, and the calcination time is 6h.
[0020] Preferably, the temperature of the drying in step (6) is 80-120°C, and the drying time is 8-12h; the temperature of the calcination is 550°C, and the calcination time is 4h; the reduction is reduction under hydrogen at 400°C for 2h.
[0021] In a second aspect, the present application provides a flat ZSM-5 supported metal palladium catalyst prepared by the above preparation method.
[0022] The catalyst comprises a flat ZSM-5 molecular sieve carrier and active metal palladium, the b-axis length of the flat ZSM-5 molecular sieve carrier is 50-60 nm, and the active metal palladium is loaded on the surface of the flat ZSM-5 molecular sieve carrier, and the metal loading amount is 0.1-2.0 wt%.
[0023] In a third aspect, the present application provides an application of the above flat ZSM-5 supported metal palladium catalyst in polycyclic aromatic hydrocarbon hydrogenation.
[0024] The specific application steps include: adding a hydrogenation substrate naphthalene (or acenaphthene), a Pd / ZSM-5 catalyst and a n-hexane solvent into a tank reactor, sealing and introducing hydrogen three times to remove residual air; then, pressurizing the reactor to 0.1-2.0 MPa with hydrogen at room temperature, then heating to 180-240℃, and keeping at a stirring speed of 800 rpm for 1-2 h. After the experiment is completed, the reaction system is naturally cooled to room temperature and the pressure is released; the reaction mixture is filtered to remove the catalyst, and the obtained organic phase is analyzed by gas chromatography-mass spectrometry and gas chromatography.
[0025] Compared with the prior art, the present application has the following beneficial effects:
[0026] 1. The flat ZSM-5 supported metal palladium catalyst synthesized in the present application comprises a flat ZSM-5 molecular sieve carrier and active metal palladium, the active metal palladium is loaded on the surface of the flat ZSM-5 molecular sieve carrier, and the flat ZSM-5 molecular sieve obtained by controlling the b-axis growth process through the proportion of ammonium fluoride solution in the synthesis process, the b-axis length of the flat ZSM-5 molecular sieve carrier is 50-60 nm;
[0027] 2. The flat ZSM-5 supported metal palladium catalyst synthesized in the present application is used for polycyclic aromatic hydrocarbon hydrogenation reaction, under the condition of 200℃, 2 MPa H2, and 1 h of reaction, the flat ZSM-5 supported metal palladium catalyst can make the conversion rate of naphthalene reach up to 51.33%, and the conversion rate of acenaphthene reach up to 95.83%;
[0028] 3. The preparation process of the present application is simple and easy to operate, improves the activity of catalytic hydrogenation, and has good application prospect in polycyclic aromatic hydrocarbon catalytic hydrogenation reaction. BRIEF DESCRIPTION OF DRAWINGS
[0029] Figure 1 is the XRD graph of the catalysts with different silicon aluminum ratios prepared in examples 1-4 of the present application;
[0030] Figure 2 is an SEM image of the catalyst with SiO2 / Al2O3= 25 prepared in Example 1 of the present application;
[0031] Figure 3 is an SEM image of the catalyst with SiO2 / Al2O3= 50 prepared in Example 2 of the present application;
[0032] Figure 4 is an SEM image of the catalyst with SiO2 / Al2O3= 80 prepared in Example 3 of the present application;
[0033] Figure 5 is an SEM image of the catalyst with SiO2 / Al2O3= 100 prepared in Example 4 of the present application;
[0034] Figure 6 is a Py-IR graph of the catalysts with different Si / Al ratios prepared in Examples 1-4 of the present application at 473 K;
[0035] Figure 7 is a Py-IR graph of the catalysts with different Si / Al ratios prepared in Examples 1-4 of the present application at 623 K;
[0036] Figure 8 is a FT-IR graph of the catalysts with different Si / Al ratios prepared in Examples 1-4 of the present application;
[0037] Figure 9 is a graph of 6 isomers of perhydroacenaphthene. DETAILED DESCRIPTION
[0038] The present application will be further described in detail with reference to the accompanying drawings and specific examples.
[0039] Examples 1-4 regulate the acidity of the platy ZSM-5 to prepare platy catalysts loaded with metal palladium with different Si / Al ratios.
[0040] Example 1
[0041] At room temperature, 14.608 g of TEOS, 10 g of deionized water and 19.965 g of TPAOH were mixed and stirred for 1.5 h to obtain a transparent synthesis gel, then 0.372 g of PB was added to the obtained gel. And stirred at 90°C for 12 h. Then, 2.164 g of NH4F was dissolved in 12.892 g of water, and after ultrasonic treatment for 5 min, it was slowly added to the above gel, and then the gel was stirred vigorously for 12 h. The obtained gel was crystallized in an autoclave at 160°C for 3 days. After the crystallization reaction was completed, the mixed solution was washed to neutral with deionized water, and then dried to obtain a molecular sieve solid powder, and then calcined at 550°C for 6 h, and finally a platy ZSM-5 molecular sieve was obtained.
[0042] A plate-like ZSM-5 supported metal palladium catalyst was prepared by an impregnation method. 0.0106 g of palladium acetate was dissolved in 20 mL of dichloromethane, and then 1 g of the plate-like ZSM-5 molecular sieve was added, stirred for 3 h, and left to stand at room temperature for 24 h. Then, it was dried at 80 °C for 12 h, followed by calcination at 550 °C for 4 h, and finally reduced at 400 °C under hydrogen for 2 h to obtain the plate-like ZSM-5 supported metal palladium catalyst, which was named Pd / ZSM-5-25.
[0043] Example 2
[0044] A transparent synthesis gel was obtained by mixing 14.654 g of TEOS, 10 g of deionized water, and 20.027 g of TPAOH at room temperature, stirring for 1.5 h, and then adding 0.187 g of PB to the obtained gel. The gel was stirred at 90 °C for 12 h. Thereafter, 2.171 g of NH4F was dissolved in 12.963 g of water, and after ultrasonic treatment for 5 min, it was slowly added to the above gel, which was then stirred vigorously for 12 h. The obtained gel was crystallized in an autoclave at 160 °C for 3 days. Thereafter, after the crystallization reaction was completed, the mixed solution was washed with deionized water until it was neutral, dried to obtain a molecular sieve solid powder, and then calcined at 550 °C for 6 h, finally obtaining a plate-like ZSM-5 molecular sieve.
[0045] A plate-like ZSM-5 supported metal palladium catalyst was prepared by an impregnation method. 0.0106 g of palladium acetate was dissolved in 20 mL of dichloromethane, and then 1 g of the plate-like ZSM-5 molecular sieve was added, stirred for 3 h, and left to stand at room temperature for 24 h. Then, it was dried at 100 °C for 10 h, followed by calcination at 550 °C for 4 h, and finally reduced at 400 °C under hydrogen for 2 h to obtain the plate-like ZSM-5 supported metal palladium catalyst, which was named Pd / ZSM-5-50.
[0046] Example 3
[0047] A transparent synthesis gel was obtained by mixing 14.670 g of TEOS, 10 g of deionized water, and 20.049 g of TPAOH at room temperature, stirring for 1.5 h, and then adding 0.117 g of PB to the obtained gel. The gel was stirred at 90 °C for 12 h. Thereafter, 2.174 g of NH4F was dissolved in 12.989 g of water, and after ultrasonic treatment for 5 min, it was slowly added to the above gel, which was then stirred vigorously for 12 h. The obtained gel was crystallized in an autoclave at 160 °C for 3 days. Thereafter, after the crystallization reaction was completed, the mixed solution was washed with deionized water until it was neutral, dried to obtain a molecular sieve solid powder, and then calcined at 550 °C for 6 h, finally obtaining a plate-like ZSM-5 molecular sieve.
[0048] Pd / ZSM-5-80 was prepared by impregnation method. 0.0106 g of palladium acetate was dissolved in 20 mL of dichloromethane, then 1 g of plate-like ZSM-5 molecular sieve was added, stirred for 3 h, and placed at room temperature for 24 h. Then, it was dried at 120 °C for 10 h, followed by calcination at 550 °C for 4 h, and finally reduced at 400 °C under hydrogen for 2 h to obtain the plate-like ZSM-5 supported metal palladium catalyst, named Pd / ZSM-5-80.
[0049] Example 4
[0050] A transparent synthesis gel was obtained by mixing 14.676 g of TEOS, 10 g of deionized water and 20.058 g of TPAOH at room temperature, stirring for 1.5 h, then adding 0.093 g of PB to the obtained gel. And stirring at 90 °C for 12 h. After that, 2.164 g of NH4F was dissolved in 12.998 g of water, and after ultrasonic for 5 min, it was slowly added to the above gel, and then the gel was stirred vigorously for 12 h. The obtained gel was crystallized in an autoclave at 160 °C for 3 days. After that, after the crystallization reaction was completed, the mixed solution was washed to neutral with deionized water, then dried to obtain a molecular sieve solid powder, and then calcined at 550 °C for 6 h, finally plate-like ZSM-5 molecular sieve was obtained.
[0051] Pd / ZSM-5-100 was prepared by impregnation method. 0.0106 g of palladium acetate was dissolved in 20 mL of dichloromethane, then 1 g of plate-like ZSM-5 molecular sieve was added, stirred for 3 h, and placed at room temperature for 24 h. Then, it was dried at 120 °C for 12 h, followed by calcination at 550 °C for 4 h, and finally reduced at 400 °C under hydrogen for 2 h to obtain the plate-like ZSM-5 supported metal palladium catalyst, named Pd / ZSM-5-100.
[0052] The XRD patterns of the catalysts prepared in Examples 1-4 are shown in Figure 1 It was found by comparison that the characteristic diffraction peaks of ZSM-5, 7.96o, 8.82o, 23.27o, 23.97o and 24.43o, existed in the catalysts with different silicon-aluminum ratios, but the crystallinity of the four catalysts was quite different. The plate-like ZSM-5 molecular sieve in the Pd / ZSM-5-25 catalyst had poor crystallinity, and the plate-like ZSM-5 molecular sieve in the Pd / ZSM-5-50 catalyst had the best crystallinity.
[0053] The SEM images of the catalysts prepared in Examples 1-4 are shown in Figures 2-5 Figures 2-5 It was found by comparison that the ZSM-5 molecular sieve in the Pd / ZSM-5-x catalysts all showed a thin plate-like structure, among which Figure 4 the b-axis length of the plate-like ZSM-5 molecular sieve in Pd / ZSM-5-25 was about 50 nm, butFigure 2 The morphology of the catalysts prepared in Examples 1-4 was poor, which was consistent with the results of XRD of Example 1.
[0054] The Py-IR spectra of the catalysts prepared in Examples 1-4 are shown in Figure 6 Figure 7 Table 1. The results of the acid evaluation of the catalysts with different Si / Al ratios are shown in Table 1. Compared with Comparative Examples 1-4, it was found that the peak areas at 1450 cm -1 and 1540 cm -1 decreased gradually with the increase of the Si / Al ratio at 200°C and 350°C. At 200°C, the catalyst Pd / ZSM-5-25 (Example 1) had the highest amount of acid, with the amount of B acid being 0.861 mmol / g and the amount of L acid being 0.173 mmol / g. The amount of B acid was higher than that of L acid in the series of catalysts prepared in Examples 1-4, which proved that most of the aluminum was in the framework of the zeolite.
[0055] Table 1. The results of the acid evaluation of the catalysts with different Si / Al ratios are shown in Table 1. Compared with Comparative Examples 1-4, it was found that the peak areas at 1450 cm -1 and 1540 cm -1 decreased gradually with the increase of the Si / Al ratio at 200°C and 350°C. At 200°C, the catalyst Pd / ZSM-5-25 (Example 1) had the highest amount of acid, with the amount of B acid being 0.861 mmol / g and the amount of L acid being 0.173 mmol / g. The amount of B acid was higher than that of L acid in the series of catalysts prepared in Examples 1-4, which proved that most of the aluminum was in the framework of the zeolite.
[0056]
[0057] The FT-IR spectra of the catalysts prepared in Examples 1-4 are shown in Figure 8 . The plate-like ZSM-5 zeolite showed asymmetric stretching vibration peaks of SiO4 tetrahedral units at 800 cm -1 , 1099 cm -1 and 1230 cm -1 . The peak at 1099 cm -1 was attributed to the asymmetric stretching vibration of Si-O-T (T represents Si or Al). However, with the increase of the SiO2 / Al2O3 ratio, this peak gradually moved to a higher wave number.
[0058] Examples 5-6: The catalysts prepared in Examples 1-4 above were applied to the catalytic hydrogenation reaction of the condensed aromatic hydrocarbons naphthalene and acenaphthene.
[0059] Example 5
[0060] In a typical experiment, 100 mg of naphthalene, 50 mg of catalyst and 20 mL of n-hexane solvent were placed in a reaction kettle. After sealing, 3 times of H2was introduced to remove residual air, and the sealing of the reaction kettle was checked. Subsequently, the reaction kettle was pressurized to 0.1-2.0 MPa with hydrogen at room temperature, then heated to 180-240°C, and kept for 1-2 h at a stirring speed of 800 rpm. After the experiment was completed, the reaction system was naturally cooled to room temperature and the pressure was released; the reaction mixture was filtered to remove the catalyst, and the obtained organic phase was analyzed by GC-MS and gas chromatography.
[0061] Table 2 is the data obtained from the catalysts prepared in Examples 1-4 at an initial pressure of 2.0 MPa, a reaction temperature of 200°C, and a stirring speed of 800 rpm for 1 h.
[0062] Table 2 is the data obtained from the catalysts prepared in Examples 1-4 at an initial pressure of 2.0 MPa, a reaction temperature of 200°C, and a stirring speed of 800 rpm for 1 h.
[0063]
[0064] The results of the evaluation of the catalysts of different acidity for catalyzing the hydrogenation of naphthalene are shown in Table 2. The catalytic activity of the catalysts decreases with increasing silica-alumina ratio. The Pd / ZSM-5-25 catalyst prepared in Example 1 has a naphthalene conversion rate of 51.33% and a decalin selectivity of 17.71%, and produces trans-decalin with high selectivity and only a small amount of cis-decalin. The results show that the acidity of the carrier has a great influence on the performance of the catalyst, and appropriate acidity can effectively improve the hydrogenation activity of the catalyst, thereby increasing the conversion rate of naphthalene and the selectivity of decalin.
[0065] Example 6
[0066] In a typical experiment, 100 mg of acenaphthene, 50 mg of catalyst, and 20 mL of n-hexane solvent were placed in a reaction kettle. After sealing, 3 times of H2was introduced to remove residual air, and the reaction kettle was checked for sealing. Subsequently, the reactor was pressurized to 0.1-2.0 MPa with hydrogen at room temperature, then heated to 180-240°C, and kept at a stirring speed of 800 rpm for 1-2 h. After the experiment, the reaction system was naturally cooled to room temperature and released pressure; the reaction mixture was filtered to remove the catalyst, and the obtained organic phase was analyzed by GC-MS and gas chromatography.
[0067] Table 3 is the data obtained from the catalysts prepared in Examples 1-4 at an initial pressure of 2.0 MPa, a reaction temperature of 200°C, and a stirring speed of 800 rpm for 1 h.
[0068] Table 3 is the data obtained from the catalysts prepared in Examples 1-4 at an initial pressure of 2.0 MPa, a reaction temperature of 200°C, and a stirring speed of 800 rpm for 1 h.
[0069]
[0070] The results of the evaluation of the catalysts of different acidity for catalyzing the hydrogenation of acenaphthene are shown in Table 3. The catalytic performance of the catalysts gradually decreases with increasing silica-alumina ratio, and the Pd / ZSM-5-25 catalyst prepared in Example 1 has the strongest hydrogenation performance, with an acenaphthene conversion rate of 95.83% and a decaline selectivity of 36.99%.
[0071] The analysis of the decaline in Table 3 shows that the decaline has six isomers, as shown in Table 4. Figure 9 The analysis of the decaline in Table 3 shows that the decaline has six isomers, as shown in Table 4.
[0072] Table 4. Isomeric composition of allhydroacenaphthene
[0073]
[0074] Deep hydrogenation of acenaphthene yields perhydroacenaphthene, which exists in six stereoisomers. Since these products appear sequentially according to their boiling points in gas chromatography, the shorter the retention time, the lower the boiling point and density, indicating a trans stereoisomer. Conversely, the longer the retention time, the higher the boiling point, indicating a cis stereoisomer. Therefore, the six stereoisomers are denoted by numbers 1-6 according to the elution order in gas chromatography. Table 4 shows the distribution of perhydroacenaphthene isomers during saturated hydrogenation of acenaphthene using different catalysts. Table 4 reveals that this series of catalysts selectively catalyzes deep hydrogenation of acenaphthene to produce substance 3, with substance 3 reaching a maximum percentage of 51.37%.
[0075] Example 7
[0076] The Pd / ZSM-5-25 prepared in Example 1, which has the best hydrogenation performance, was compared with a catalyst supported on commercially available bulk ZSM-5-25, wherein the Pd metal loading method and loading amount were the same as in Example 1.
[0077] The hydrogenation substrate naphthalene, catalyst, and n-hexane solvent were added to a batch reactor, which was then sealed and purged with hydrogen three times to remove residual air. Subsequently, the reactor was pressurized to 0.1-2.0 MPa with hydrogen at room temperature, then heated to 180-240 °C and maintained at a stirring speed of 800 rpm for 1-2 h. After the experiment, the reaction system was allowed to cool naturally to room temperature and the pressure was released. The reaction mixture was filtered to remove the catalyst, and the obtained organic phase was analyzed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-mass spectrometry (GC-MS).
[0078] Table 5 shows the data obtained for the two catalysts under the following conditions: initial pressure 2.0 MPa, reaction temperature 200 °C, and stirring speed 800 rpm for 1 h.
[0079] Table 5 Evaluation results of naphthalene hydrogenation catalyzed by different catalysts
[0080]
[0081] The results show that, comparing the reaction performance of Example 1 (with a silicon-to-aluminum ratio of 25) and commercial block ZSM-5-25, the conversion rate of Example 1 (51.33%) is much higher than that of commercial ZSM-5-25 (26.18%). This demonstrates that, under the same acidic conditions, the diffusion effect of the plate-shaped molecular sieve is higher than that of commercial block ZSM-5-25, which is beneficial to the diffusion of the macromolecular reactant naphthalene and hydrogenation products, and improves the catalytic hydrogenation activity.
[0082] The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any modification, equivalent replacement and improvement within the technical range disclosed by the present application and within the spirit and principle of the present application should be covered within the protection scope of the present application.
Claims
1. Use of a flat sheet ZSM-5 supported metal palladium catalyst for the hydrogenation of polycyclic aromatic hydrocarbons, characterised in that, The flat-plate ZSM-5 supported metal palladium catalyst is prepared by the following steps: (1) mixing a silicon source, deionized water and a template agent at room temperature, stirring until a transparent synthesis gel is obtained, the molar composition of which is SiO2 / template agent=1:0.35; (2) adding an aluminum source to the gel obtained in step (1) and stirring at 90°C for 12h; the amount of aluminum source added is kept at nSiO2 / nAl2O3=1:(0.01-0.04); (3) dissolving ammonium fluoride in deionized water, slowly adding the gel obtained in step (2) after ultrasonic treatment, and stirring vigorously for 12h; the amount of ammonium fluoride added is kept at nSiO2 / nNH4F=1:(0.1-1.0); (4) hydrothermally crystallizing the gel obtained in step (3), after the crystallization reaction is completed, the obtained product is washed to neutral with deionized water and dried to obtain a molecular sieve solid powder; (5) grinding the obtained molecular sieve solid powder, calcining to remove the template agent, and obtaining a flat-plate ZSM-5 molecular sieve carrier; (6) dissolving palladium acetate in dichloromethane, adding the flat-plate ZSM-5 molecular sieve carrier to it after ultrasonic treatment, stirring vigorously for 3h, and standing at room temperature for 24h; then, drying, calcining and reducing to obtain a flat-plate ZSM-5 supported metal palladium catalyst.
2. Use according to claim 1, characterized in that, The polycyclic aromatic hydrocarbon is naphthalene or acenaphthene.
3. Use according to claim 1, characterised in that, The reaction temperature for the hydrogenation of the polycyclic aromatic hydrocarbon is 180-240°C; the reaction pressure is 0.1-2MPa; and the reaction time is 1-2h.
4. Use according to claim 1, characterized in that, The silicon source in step (1) is selected from at least one of tetraethyl orthosilicate, silica sol, water glass, white carbon black and solid silica gel; the template agent is selected from at least one of tetrapropylammonium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide and tetrapropylammonium hydroxide; and the aluminum source in step (2) is selected from at least one of pseudo-boehmite, sodium metaaluminate, aluminum sulfate, aluminum chloride, aluminum nitrate and aluminum isopropylate.
5. The use according to claim 1, characterized in that, The temperature for the crystallization in step (4) is 160°C, and the crystallization time is 72h.
6. Use according to claim 1, characterized in that, The temperature for the calcination in step (5) is 550°C, and the calcination time is 6h.
7. The use according to claim 1, characterized in that, The temperature for the drying in step (6) is 80-120°C, and the drying time is 8-12h; the temperature for the calcination is 550°C, and the calcination time is 4h; and the reduction refers to reduction under hydrogen at 400°C for 2h.
8. The use according to claim 1, characterized in that, The flat plate-shaped ZSM-5 supported metal palladium catalyst comprises a flat plate-shaped ZSM-5 molecular sieve carrier and active metal palladium, the active metal palladium is loaded on the surface of the flat plate-shaped ZSM-5 molecular sieve carrier, and the flat plate-shaped ZSM-5 molecular sieve carrier b The axial length is 50-60 nm, and the metal loading amount is 0.1-2.0 wt%.
Citation Information
Patent Citations
ZSM-5 molecular sieve as well as preparation method and application thereof
CN119038575A