Phenol hydroalkylation supported catalyst and preparation method and application thereof

Abstract

The invention provides a supported catalyst for phenol hydroalkylation as well as a preparation method and application of the supported catalyst. The catalyst consists of a metal site and a molecular sieve carrier and is prepared by adopting a dissolution recrystallization method, and a silicate species is formed through reaction between metal and a dissolved molecular sieve silicon source, so that the metal is effectively stabilized and the aggregation of the metal is inhibited; in the recrystallization process, metal is encapsulated in the molecular sieve crystal, and meanwhile, a micro-medium composite molecular sieve carrier is constructed. According to the catalyst, high-density Bronsted acid sites in pore channels are fully utilized, the alkylation reaction of phenol and cyclohexene generated in situ is remarkably promoted, and the selectivity of cyclohexylphenol is improved. Meanwhile, the micro-dielectric composite structure effectively weakens diffusion limitation, and generation of polycyclic oxygen-containing by-products is remarkably reduced. According to the invention, green in-situ construction of a metal site and an acid site of the catalyst is realized, and the yield of cyclohexylphenol produced by hydroalkylation of phenol is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysis technology, and relates to a catalyst for synthesizing cyclohexylphenol through phenol hydrogenation alkylation and a preparation method and application thereof. BACKGROUND

[0002] Cyclohexylphenol, as an important platform molecule of phenolic compounds, is widely used in the manufacturing fields of dyes, drugs, resins and bactericides, and shows extremely high utilization value. With the rapid development of the global pharmaceutical and chemical industries, it is foreseeable that cyclohexylphenol will have great market space in emerging fields such as special chemicals and new materials.

[0003] At present, cyclohexylphenol is mainly prepared through alkylation of phenol and cyclohexene (or cyclohexanol), and the catalysts are concentrated H2SO4 and H3PO4. However, liquid acid catalysts have strong corrosion, high separation cost and will cause pollution. Hydrogenation alkylation of phenol on a heterogeneous catalyst is an alternative route for producing cyclohexylphenol. This process has the following significant advantages: only phenol is used as a single raw material, which effectively reduces the cost of raw materials; a heterogeneous solid catalyst is used, which is easy to separate and environmentally friendly; the hydrogenation reaction and the alkylation reaction of phenol are coupled, realizing a continuous process of one-step hydrogenation alkylation, which has the advantages of simple process and low energy consumption. However, in the actual reaction process, the occurrence of deep hydrogenation or secondary alkylation will lead to the generation of by-products cyclohexane and di-cyclohexylphenol, thereby reducing the selectivity of cyclohexylphenol. In the prior art, the catalyst for hydrogenation alkylation of phenol is mainly a supported metal + molecular sieve catalyst. The number of metal sites and acid sites is not matched and the distance is far, which leads to a low space-time yield of cyclohexylphenol (<1 mmol·g -1 ·h -1 ) and a high yield of by-product cyclohexane (Green Chemistry, 2022, 24(23): 9168-9179; Catalysis Today, 2022, 390-391: 135-145). Therefore, it is of great significance to design a catalyst for efficiently synthesizing cyclohexylphenol through hydrogenation alkylation of phenol.

[0004] The existing research shows that the two-component catalyst with hydrogenation function and alkylation function can realize the production of cyclohexylbenzene by benzene hydrogenation alkylation. The catalyst for cyclohexylbenzene synthesis (CN107930675A, CN107930681A, CN107930679A) includes a hydrogen type zeolite molecular sieve carrier and an active component loaded on the carrier; the active component includes a noble metal and an iron group element. CN119500238A discloses a catalyst for preparing cyclohexylbenzene from benzene, which includes a copper mordenite and an active metal nickel loaded therein, and the presence of copper element can improve the conversion rate of benzene and the selectivity of cyclohexylbenzene. In addition, research shows that the encapsulated metal-molecular sieve catalyst not only can realize the reduction of metal particle size, and the close synergistic effect between metal and acid can improve the selectivity of cyclohexylbenzene (CN109772432A, CN118287132A). However, the current construction of the encapsulated metal-molecular sieve catalyst mostly adopts the seed crystal method, that is, the active component is loaded on the molecular sieve, reduced, and then introduced into the silica-alumina gel for secondary crystallization, and the catalyst is obtained after the second reduction. This strategy has a complex process, high energy consumption for multiple reductions, and high catalyst preparation cost due to the noble metal active component. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application aims to provide a phenol hydrogenation alkylation supported catalyst, a preparation method and application thereof. The catalyst is prepared by a dissolution recrystallization method, the metal species is encapsulated in the molecular sieve crystal, the high-density Brønsted acid sites in the molecular sieve channel are fully utilized, the alkylation reaction of phenol and in-situ generated cyclohexene is promoted, the selectivity of cyclohexylphenol is greatly improved, a micro-intermediate composite molecular sieve carrier is constructed, the diffusion limitation is effectively weakened, and the generation of polycyclic oxygen-containing by-products is significantly reduced.

[0006] The present application is realized by the following technical solutions:

[0007] The present application provides a preparation method of a phenol hydrogenation alkylation supported catalyst, which comprises the following specific steps:

[0008] (1) The molecular sieve is stirred with an aqueous solution of a template agent at room temperature to obtain a gel A;

[0009] (2) The metal precursor is added to the gel A, and the gel B is obtained after stirring uniformly at room temperature;

[0010] (3) The gel B is placed in a crystallization kettle for dissolution recrystallization, and after being taken out, it is washed, dried and reduced to obtain the phenol hydrogenation alkylation supported catalyst.

[0011] In step (1) of the present application, the ratio of the molecular sieve to the aqueous template solution is 1 g:10 mL; the concentration of the aqueous template solution is 0.4-1.5 M, preferably 0.6-1.2 M. The molecular sieve is selected from one of HBeta, HY, and HMOR, and the template is tetraethylammonium hydroxide. The stirring time is 1-8 h, preferably 2-6 h.

[0012] In step (2) of the present application, the metal precursor is selected from one of a metal nitrate, a metal sulfate, a metal acetate, a metal citrate, or a metal chloride, the metal is selected from one of Fe, Co, Ni, Cu, and Zn, and the mass of the metal precursor to the mass of the molecular sieve is 10-60 wt%, preferably 20-60 wt%. The stirring time is 0.5-3 h, preferably 1-2 h.

[0013] In step (3) of the present application, the recrystallization temperature is 80-200℃, preferably 100-170℃, and the recrystallization time is 12-48 h; when washing after crystallization, the amount of deionized water is 5-20 times the amount of the crystallization product by weight, so that the final supernatant is neutral; the drying temperature is 90-110℃, and the drying time is 6-12 h; the reduction temperature is 350-750℃, preferably 450-650℃, the reduction time is 2-4 h, and the reduction atmosphere is hydrogen.

[0014] In the present application, the stirring mode is mechanical stirring, and the preferred stirring speed is 1000 r / min.

[0015] The present application provides a phenol hydroalkylation supported catalyst prepared by the above method, which is composed of a metal and a molecular sieve carrier, the mass of the metal to the mass of the molecular sieve is 2-12 wt%, preferably 4-10 wt%; the metal is one of Fe, Co, Ni, Cu, and Zn, and the molecular sieve is one of HBeta, HY, and HMOR; the metal particles in the catalyst are encapsulated inside the molecular sieve carrier, the metal dispersion is 5-30%, preferably 10-30%, and the size of the metal particles is 3-20 nm, preferably 3-10 nm.

[0016] In the present application, the acid amount of the catalyst is 100-600 μmol / g, preferably 200-500 μmol / g.

[0017] In the present application, the specific surface area of the catalyst is 200-800 m 2 ·g -1 , preferably 400-800 m 2 ·g -1 ; the specific surface area of the micropores of the catalyst is 100-500 m 2 ·g -1, preferably 150-450 m 2 ·g -1 ; the mesopore specific surface area of the catalyst is 50-300 m 2 ·g -1 , preferably 100-200 m 2 ·g -1 .

[0018] The application also provides application of the above catalyst in a phenol hydroalkylation reaction, and the phenol hydroalkylation reaction is under the following conditions: the reaction temperature is 100-200 DEG C, preferably 130-170 DEG C; the hydrogen pressure is 0.5-6 MPa, preferably 2-5 MPa; the catalyst to phenol mass ratio is 0.1-0.4, preferably 0.15-0.35; and the reaction time is 0.5-8 h, preferably 2-6 h.

[0019] The supported catalyst prepared by the application has excellent phenol hydroalkylation performance, and the cyclohexyl phenol yield is up to 45.5%, the phenol conversion rate is 80.5%, and the cyclohexyl phenol selectivity is 56.5%. The cyclohexyl phenol space-time yield is 2.43 mmol·g -1 ·h -1 .

[0020] The application adopts a dissolution recrystallization method to prepare a phenol hydroalkylation supported catalyst, directly introduces a metal precursor into a mixed gel of a molecular sieve and a template agent, under alkaline high-temperature conditions, the molecular sieve is first dissolved and a large amount of active silicon species is generated, the silicon species is recrystallized to form a molecular sieve under the action of the template agent, and the silicon species is reacted with the metal precursor to generate silicate species. The silicate species is encapsulated in the inside of the molecular sieve in the recrystallization process, so that the high-density Brønsted acid sites in the molecular sieve channel are fully utilized, and the space-time yield of cyclohexyl phenol is significantly improved. In addition, the alkaline system also plays a role in stabilizing metal ions and reducing metal particle size. It is worth noting that the control of the template agent concentration is crucial: too low a template agent concentration will significantly reduce the recrystallization rate, cause loss of the specific surface area and acid amount of the molecular sieve, and cannot realize effective encapsulation of the metal; and too high a template agent concentration will cause too high alkalinity, so that the molecular sieve matrix is completely dissolved. Under the condition of optimizing the template agent concentration, the application realizes synchronous construction of high-dispersion metal encapsulation and micro-intermediate composite molecular sieve.

[0021] Compared with the prior art, the application has the following beneficial technical effects:

[0022] (1) The metal molecular sieve catalyst is prepared by a dissolution recrystallization method, compared with traditional impregnation method, seed method and dissolution recrystallization method, the process of loading metal is saved. Silicate species is formed by the reaction between metal and dissolved molecular sieve silicon source, effective stabilization of metal and regulation of particle size are realized; in the recrystallization process, the metal is encapsulated in the molecular sieve crystal, effectively solving the problem of mismatching of metal sites and acid sites and long distance.

[0023] (2) While realizing metal encapsulation, the micro-intermediate composite molecular sieve carrier constructed effectively weakens diffusion limitation, improves the activity of the catalyst, and significantly reduces the generation of polycyclic oxygen-containing by-products.

[0024] (3) The catalyst preparation process is simple, and the calcination process is saved. This not only reduces energy consumption and catalyst preparation cost, but also avoids the aggregation of metal in the calcination process, increases the dispersion degree of metal, and improves the hydrogenation activity of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 XRD spectrum of the catalyst synthesized in Example 1-7.

[0026] Figure 2 TEM image of the catalyst synthesized in Example 1.

[0027] Figure 3 TEM image of the catalyst synthesized in Comparative Example 1.

[0028] Figure 4 Sliced-HAADF-STEM image of the catalyst synthesized in Example 1.

[0029] Figure 5 Sliced-HAADF-STEM image of the catalyst synthesized in Comparative Example 1. DETAILED DESCRIPTION

[0030] The details of the application can be more clearly understood in conjunction with the description of the specific embodiments of the application in combination with the accompanying drawings. However, the specific embodiments of the application described herein are only for the purpose of explaining the application, and cannot be understood as limiting the application in any way.

[0031] Example 1

[0032] The present embodiment provides a phenol hydroalkylation supported Ni-Beta catalyst and a preparation method thereof.

[0033] Synthesis of Ni-Beta catalyst: Take 5 g of commercial HBeta zeolite, add 50 mL (0.9 M) of TEAOH solution, stir at room temperature for 3 h to obtain gel A, then add 1.486 g of Ni(NO3)2·6H2O to gel A, stir for another 1 h to obtain gel B, put it into a 100 mL crystallization kettle, recrystallize at 160 °C for 24 h, take out the solid product, centrifugal wash with deionized water until the supernatant is neutral, dry at 100 °C for 12 h, reduce under hydrogen atmosphere at 550 °C for 2 h to obtain the Ni-Beta catalyst. The catalyst has a Ni loading of 6 wt%, a metal dispersion of 19.2%, and Ni located inside the Beta zeolite. The catalyst has an acid amount of 345 μmol / g, a specific surface area of 560 m 2 ·g -1 , a micropore specific surface area of 404 m 2 ·g -1 , and a mesopore specific surface area of 156 m 2 ·g -1 .

[0034] Example 2

[0035] The present example provides a phenol hydroalkylation supported Ni-Y catalyst and a preparation method thereof.

[0036] Synthesis of Ni-Y catalyst: Take 5 g of commercial HY zeolite, add 50 mL (1.2 M) of TEAOH solution, stir at room temperature for 3 h to obtain gel A, then add 1.486 g of Ni(NO3)2·6H2O to gel A, stir for another 1 h to obtain gel B, put it into a 100 mL crystallization kettle, recrystallize at 100 °C for 12 h, take out the solid product, centrifugal wash with deionized water until the supernatant is neutral, dry at 100 °C for 12 h, reduce under hydrogen atmosphere at 550 °C for 2 h to obtain the Ni-Y catalyst. The catalyst has a Ni loading of 6 wt%, a metal dispersion of 15.0%, and Ni located inside the Y zeolite. The catalyst has an acid amount of 437 μmol / g, a specific surface area of 662 m 2 ·g -1 , a micropore specific surface area of 472 m 2 ·g -1 , and a mesopore specific surface area of 190 m 2 ·g -1 .

[0037] Example 3

[0038] The present example provides a phenol hydroalkylation supported Ni-MOR catalyst and a preparation method thereof.

[0039] Synthesis of Ni-MOR catalyst: Take 5 g of commercial HMOR molecular sieve, add 50 mL (1.2 M) of TEAOH solution, stir at room temperature for 3 h to obtain gel A, then add 1.486 g of Ni(NO3)2·6H2O to gel A, stir for another 1 h to obtain gel B, put it into a 100 mL crystallization kettle, recrystallize at 170 °C for 24 h, take out the solid product, centrifugal wash with deionized water until the supernatant is neutral, dry at 100 °C for 12 h, reduce under hydrogen atmosphere at 550 °C for 2 h to obtain the Ni-MOR catalyst. The catalyst has a Ni loading of 6 wt%, a metal dispersion of 16.7%, and Ni located inside the MOR molecular sieve. The catalyst has an acid amount of 310 μmol / g, a specific surface area of 420 m 2 ·g -1 , a micropore specific surface area of 259 m 2 ·g -1 , and a mesopore specific surface area of 161 m 2 ·g -1 .

[0040] Example 4

[0041] The present example provides a phenol hydroalkylation supported Fe-Beta catalyst and a preparation method thereof.

[0042] Synthesis of Fe-Beta catalyst: Take 5 g of commercial HBeta molecular sieve, add 50 mL (0.9 M) of TEAOH solution, stir at room temperature for 3 h to obtain gel A, then add 2.893 g of Fe(NO3)3·9H2O to gel A, stir for another 1 h to obtain gel B, put it into a 100 mL crystallization kettle, recrystallize at 160 °C for 24 h, take out the solid product, centrifugal wash with deionized water until the supernatant is neutral, dry at 100 °C for 12 h, reduce under hydrogen atmosphere at 550 °C for 2 h to obtain the Fe-Beta catalyst. The catalyst has a Fe loading of 8 wt%, a metal dispersion of 12.1%, and Fe located inside the Beta molecular sieve. The catalyst has an acid amount of 337 μmol / g, a specific surface area of 552 m 2 ·g -1 , a micropore specific surface area of 406 m 2 ·g -1 , and a mesopore specific surface area of 146 m 2 ·g -1 .

[0043] Example 5

[0044] The present example provides a phenol hydroalkylation supported Co-Beta catalyst and a preparation method thereof.

[0045] Synthesis of Co-Beta catalyst: Take 5 g of commercial HBeta zeolite, add 50 mL (0.9 M) of TEAOH solution, stir at room temperature for 3 h to obtain gel A, then add 1.482 g of Co (NO3)2·6H2O to gel A, stir for another 1 h to obtain gel B, put it into a 100 mL crystallization kettle, recrystallize at 160 °C for 24 h, take out the solid product, centrifugal wash with deionized water until the supernatant is neutral, dry at 100 °C for 12 h, reduce under hydrogen atmosphere at 650 °C for 2 h to obtain Co-Beta catalyst. The Co loading of the catalyst is 6 wt%, the metal dispersion is 17.7%, and Co is located inside the Beta zeolite. The acid amount of the catalyst is 365 μmol / g, the specific surface area is 575 m 2 ·g -1 , the micropore specific surface area is 399 m 2 ·g -1 , and the mesopore specific surface area is 176 m 2 ·g -1 .

[0046] Example 6

[0047] The present example provides a phenol hydroalkylation supported Cu-Beta catalyst and a preparation method thereof.

[0048] Synthesis of Cu-Beta catalyst: Take 5 g of commercial HBeta zeolite, add 50 mL (0.9 M) of TEAOH solution, stir at room temperature for 3 h to obtain gel A, then add 1.901 g of Cu (NO3)2·3H2O to gel A, stir for another 1 h to obtain gel B, put it into a 100 mL crystallization kettle, recrystallize at 160 °C for 24 h, take out the solid product, centrifugal wash with deionized water until the supernatant is neutral, dry at 100 °C for 12 h, reduce under hydrogen atmosphere at 550 °C for 2 h to obtain Cu-Beta catalyst. The Cu loading of the catalyst is 10 wt%, the metal dispersion is 12.6%, and Cu is located inside the Beta zeolite. The acid amount of the catalyst is 310 μmol / g, the specific surface area is 502 m 2 ·g -1 , the micropore specific surface area is 369 m 2 ·g -1 , and the mesopore specific surface area is 133 m 2 ·g -1 .

[0049] Example 7

[0050] The present example provides a phenol hydroalkylation supported Zn-Beta catalyst and a preparation method thereof.

[0051] Synthesis of Zn-Beta catalyst: Take 5 g commercial HBeta molecular sieve, add 50 mL (0.9 M) TEAOH solution, stir at room temperature for 3 h to obtain gel A, then add 2.275 g Zn(NO3)2·6H2O to gel A, stir for 1 h to obtain gel B, put it into a 100 mL crystallization kettle, recrystallize at 160 °C for 24 h, take out the solid product, centrifugal wash with deionized water until the supernatant is neutral, dry at 100 °C for 12 h, reduce under hydrogen atmosphere at 550 °C for 2 h to obtain Zn-Beta catalyst. The catalyst Zn loading is 10 wt%, the metal dispersion is 11.6%, and Zn is located inside the Beta molecular sieve. The catalyst acid amount is 321 μmol / g, the specific surface area is 529 m 2 ·g -1 , the micropore specific surface area is 379 m 2 ·g -1 , and the mesopore specific surface area is 150 m 2 ·g -1 .

[0052] Comparative Example 1

[0053] The catalyst Ni / Beta-im was prepared by impregnation method, compared with Example 1. Weigh 1.486 g Ni(NO3)2·6H2O, dissolve in 4.6 g water, ultrasonic until completely dissolved, then add 5 g commercial HBeta molecular sieve, stir uniformly, room temperature for 22 h, dry at 100 °C for 4 h, calcine at 400 °C for 4 h, finally reduce under hydrogen atmosphere at 550 °C for 2 h to obtain catalyst Ni / Beta-im. The catalyst Ni loading is 6 wt%, the metal dispersion is 7.2%, and Ni is located on the outer surface of the Beta molecular sieve. The catalyst acid amount is 378 μmol / g, the specific surface area is 499 m 2 ·g -1 , the micropore specific surface area is 421 m 2 ·g -1 , and the mesopore specific surface area is 78 m 2 ·g -1 .

[0054] Comparative Example 2

[0055] The concentration of the TEAOH solution was reduced to 0.3 M in comparison to Example 1. Synthesis of Ni-Beta-0.3 catalyst: 5 g of commercial HBeta molecular sieve was added to 50 mL (0.3 M) of TEAOH solution and stirred at room temperature for 3 h to obtain gel A, then 1.486 g of Ni(NO3)2.6H2O was added to gel A and stirred for another 1 h to obtain gel B, which was placed in a 100 mL crystallization kettle and recrystallized at 160 °C for 24 h. After the solid product was removed, it was washed with deionized water by centrifugation until the supernatant was neutral, dried at 100 °C for 12 h, and reduced under hydrogen atmosphere at 550 °C for 2 h to obtain the Ni-Beta catalyst. The catalyst had a Ni loading of 6 wt%, a metal dispersion of 10.4%, and Ni located both inside and outside the Beta molecular sieve. The catalyst had an acid amount of 287 μιηοΙ / g, a specific surface area of 419 m2 / g, a micropore specific surface area of 312 m2 / g, and a mesopore specific surface area of 107 m2 / g. 2 ·g -1 2 ·g -1 2 ·g -1 .

[0056] Comparative Example 3

[0057] The concentration of the TEAOH solution was increased to 1.6 M in comparison to Example 1. Synthesis of Ni-Beta-1.6 catalyst: 5 g of commercial HBeta molecular sieve was added to 50 mL (1.6 M) of TEAOH solution and stirred at room temperature for 3 h to obtain gel A, then 1.486 g of Ni(NO3)2.6H2O was added to gel A and stirred for another 1 h to obtain gel B, which was placed in a 100 mL crystallization kettle and recrystallized at 160 °C for 24 h. After the solid product was removed, it was washed with deionized water by centrifugation until the supernatant was neutral, dried at 100 °C for 12 h, and reduced under hydrogen atmosphere at 550 °C for 2 h to obtain the Ni-Beta catalyst. The catalyst had a Ni loading of 6 wt%, a metal dispersion of 8.5%, and Ni located both inside and outside the Beta molecular sieve. The catalyst had an acid amount of 241 μιηοΙ / g, a specific surface area of 395 m2 / g, a micropore specific surface area of 237 m2 / g, and a mesopore specific surface area of 158 m2 / g. 2 ·g -1 2 ·g -1 2 ·g -1 .

[0058] Catalyst performance evaluation

[0059] ​​​​The catalysts prepared in the above examples and comparative examples were subjected to catalytic performance evaluation for phenol hydroalkylation. The reaction conditions included: a 50 mL mechanically stirred autoclave type reactor was used, the reaction temperature was 160°C, the reaction pressure was 4 MPa, the catalyst to phenol mass ratio (i.e. the mass ratio of catalyst to phenol) was 0.25, and the reaction time was 4 h. The phenol conversion, cyclohexylphenol selectivity and cyclohexylphenol yield are shown in Table 1. The conversion, selectivity and yield were obtained by gas chromatography detection of the products and calculation.

[0060] Phenol conversion (%) = (moles of phenol in raw material - moles of phenol in product) ÷ moles of phenol in raw material × 100%. The moles of phenol in raw material were known. The moles of phenol in product were obtained by gas chromatography detection.

[0061] Cyclohexylphenol selectivity (%) = moles of phenol consumed to generate cyclohexylphenol ÷ moles of phenol converted × 100%. The moles of cyclohexylphenol generated were obtained by gas chromatography detection, and the moles of phenol consumed to generate cyclohexylphenol were calculated by chemical equation. Moles of phenol converted = moles of phenol in raw material - moles of phenol in product.

[0062] Cyclohexylphenol yield (%) = phenol conversion × cyclohexylphenol selectivity × 100%.

[0063] Table 1. Results of phenol hydroalkylation catalytic performance As can be seen from Table 1, compared with the comparative examples, the catalysts of the examples of the present application have significantly improved selectivity and yield for phenol hydroalkylation to synthesize cyclohexylphenol, and have high catalytic selectivity for phenol hydroalkylation to synthesize cyclohexylphenol.

[0064] As can be seen from Table 1, compared with the comparative examples, the catalysts of the examples of the present application have significantly improved selectivity and yield for phenol hydroalkylation to synthesize cyclohexylphenol, and have high catalytic selectivity for phenol hydroalkylation to synthesize cyclohexylphenol. Figure 1 As can be seen from Table 1, compared with the comparative examples, the catalysts of the examples of the present application have significantly improved selectivity and yield for phenol hydroalkylation to synthesize cyclohexylphenol, and have high catalytic selectivity for phenol hydroalkylation to synthesize cyclohexylphenol. Figure 2 , Figure 3 , Figure 4 and Figure 5 As can be seen from Table 1, compared with the comparative examples, the catalysts of the examples of the present application have significantly improved selectivity and yield for phenol hydroalkylation to synthesize cyclohexylphenol, and have high catalytic selectivity for phenol hydroalkylation to synthesize cyclohexylphenol.

Claims

1. A method for preparing a supported catalyst for the hydrogenation and alkylation of phenol, characterized in that, The specific steps include the following: (1) The molecular sieve and template agent aqueous solution were stirred at room temperature and mixed evenly to obtain gel A; (2) Add a metal precursor to gel A and stir at room temperature to obtain gel B; (3) Gel B was placed in a crystallization vessel to dissolve and recrystallize. After removal, it was washed, dried and reduced to finally obtain the phenol hydrogenation alkylation supported catalyst.

2. The method for preparing a supported catalyst for the hydrogenation alkylation of phenol according to claim 1, characterized in that, In step (1), the ratio of molecular sieve to template agent aqueous solution is 1 g: 10 mL; the concentration of template agent aqueous solution is 0.4-1.5 M; the molecular sieve is selected from one of HBeta, HY, and HMOR; the template agent is tetraethylammonium hydroxide; and the stirring time is 1-8 h.

3. The method for preparing a supported catalyst for the hydrogenation alkylation of phenol according to claim 1, characterized in that, In step (2), the metal precursor is selected from one of metal nitrates, sulfates, acetates, citrates or chlorides, and the metal is selected from one of Fe, Co, Ni, Cu, Zn. The mass of the metal precursor is 10-60 wt% of the molecular sieve mass. The stirring time is 0.5-3 h.

4. The method for preparing a supported catalyst for the hydrogenation alkylation of phenol according to claim 1, characterized in that, In step (3), the recrystallization temperature is 80-200℃ and the recrystallization time is 12-48 h; during washing after crystallization, the amount of deionized water used is 5-20 times the weight of the crystallized product to make the final supernatant neutral; the drying temperature is 90-110℃ and the drying time is 6-12 h; the reduction temperature is 350-750℃ and the reduction time is 2-4 h, and the reduction atmosphere is hydrogen.

5. The method for preparing a supported catalyst for the hydrogenation alkylation of phenol according to claim 1, characterized in that, The stirring method is mechanical stirring, and the stirring speed is 1000 r / min.

6. A phenol hydrogenation alkylation supported catalyst prepared by any one of claims 1-5, characterized in that, The catalyst is composed of metal sites and a molecular sieve support, wherein the mass of the metal is equal to the mass of the molecular sieve by 2-12 wt%; the metal is one of Fe, Co, Ni, Cu, and Zn, and the molecular sieve is one of HBeta, HY, and HMOR; the metal particles in the catalyst are encapsulated inside the molecular sieve support, with a metal dispersion of 5-30% and a metal particle size of 3-20 nm.

7. The supported catalyst for phenol hydrogenation alkylation according to claim 6, characterized in that, The catalyst has an acidity of 100-600 μmol / g and a specific surface area of ​​200-800 m². 2 ·g -1 The specific surface area of ​​the micropores is 100-500 m². 2 ·g -1 Mesoporous specific surface area is 50-300 m² 2 ·g -1 .

8. The supported catalyst for phenol hydrogenation alkylation according to claim 7, characterized in that, The catalyst has an acidity of 200-500 μmol / g and a specific surface area of ​​400-800 m². 2 ·g -1 The specific surface area of ​​the micropores is 150-450 m². 2 ·g -1 Mesoporous specific surface area is 100-200 m² 2 ·g -1 .

9. The use of the catalyst according to any one of claims 6-8 in the hydrogenation alkylation reaction of phenol, characterized in that, The phenol hydrogenation alkylation reaction conditions are as follows: reaction temperature 100-200℃, hydrogen pressure 0.5-6 MPa, agent-to-oil ratio 0.1-0.4, and reaction time 0.5-8 h.

10. The application of the catalyst according to claim 9 in the hydrogenation alkylation reaction of phenol, characterized in that, The yield of cyclohexylphenol was 45.5%, the conversion of phenol was 80.5%, and the selectivity of cyclohexylphenol was 56.5%. The space-time yield of cyclohexylphenol, based on the mass of the catalyst, was 2.43 mmol·g. -1 ·h -1 .

Images