An alkylation catalyst, its preparation method and application

Abstract

The present invention relates to the technical field of organic synthesis catalysts, and specifically relates to an alkylation catalyst, a preparation method thereof, and an application. The alkylation catalyst of the present invention is a Mannich base-modified iron-based spinel oxide catalyst supported on mesoporous titanium dioxide. Mesoporous titanium dioxide serves as a carrier, and the iron-based spinel oxide can be well and uniformly loaded in the mesoporous titanium dioxide. The Mannich base has strong alkalinity and a very high compatibility with mesoporous titanium dioxide, can be stably loaded in the catalyst, can well activate phenolic hydroxyl groups, greatly reduce the reaction temperature, reduce catalyst carbon deposition, and thus extend the service life of the catalyst. The catalyst has the following advantages: high catalytic activity, good reaction selectivity, a reaction conversion rate as high as 99% and a yield as high as 97%; high catalytic efficiency, capable of realizing the efficient and rapid synthesis of products at a lower temperature; good stability, and can be recycled multiple times or operate for a long period.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis catalysts, and particularly relates to an alkylation catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] Anisole, also known as methoxybenzene, methyl phenyl ether. Anisole has a wide range of applications in the fields of photosensitizers, dyes, pharmaceuticals, pesticides, fragrances, etc. For example, it is often used in the synthesis of beer antioxidants, stabilizers for plastics, and ultraviolet stabilizers for ethylene polymers; or as a primary raw material for the production of fragrances, pesticides, and dyes, or for improving the octane number of gasoline, etc.

[0003] Anisole is prepared by the alkylation reaction of phenol, and this alkylation reaction is an electrophilic substitution reaction. Due to the partial positive polarization of oxygen in phenol and the resonance stabilization of the conjugate base, the O-H bond on the benzene ring is easily broken. Although the alkylating agent is easily attacked by the oxygen atom in the hydroxyl group during the reaction process, it is also easily attacked by the electrons on the benzene ring. Therefore, the hydroxyl group in phenol easily directs the electrophilic reagent to the ortho and para positions, and during the phenol alkylation process, in addition to anisole, various by-products such as cresol, substituted anisole, dimethylphenol, or trimethylphenol may be formed. Therefore, in the prior art, in order to improve the selectivity and yield of anisole, acid-base catalysts are usually used as the catalysts for this electrophilic substitution reaction. Moreover, it has been found that the orientation of phenol on the catalyst surface, the type of methylation agent, reaction conditions, acid-base strength, and the deactivation rate of the catalyst may all be important factors affecting the selectivity and yield of anisole.

[0004] In the prior art, the alkylation reaction of phenol to synthesize anisole mainly uses dimethyl sulfate (DMS), iodomethane, dimethyl carbonate (DMC), and methanol as methylation reagents. Among them, dimethyl sulfate and iodomethane have relatively high reaction activities and can react with phenol ions in the liquid phase at room temperature or slightly above room temperature, and obtain high conversion rates. At present, the dimethyl sulfate process is mainly used in China to produce anisole, but this process will generate difficult-to-treat phenol-containing wastewater; and dimethyl sulfate is a highly toxic chemical, so the application of this process is limited. Iodomethane is expensive and it is difficult to achieve large-scale production as a methylation reagent. Although dimethyl carbonate is green and environmentally friendly, its price is also relatively high and it is not suitable for large-scale industrial production of anisole. Using methanol as a methylation reagent to react with phenol to synthesize anisole has the potential advantages of low raw material cost and simple post-treatment.

[0005] At present, there are various catalytic systems for preparing anisole using methanol as a methylation reagent, such as molecular sieves, metal oxides, phosphates, sulfates, and other solid acid-base catalysts.

[0006] In the prior art, a literature (Balsama et al, Applied Catalysis, 1984, 13, 161 - 170.) compared several zeolite molecular sieves (X, Y, ZSM types) aiming to evaluate their reactivity, stability, distribution of alkylation products, etc. The results showed that the conversion rates were all low when the catalytic reaction was carried out at a lower temperature. Another literature (Kirichenko et al, Petroleum Chemistry, 2008, 48, 389 - 392.) reported that using NaX molecular sieve as a catalyst, anisole was synthesized by the phenol - methanol method. Under certain conditions, both the conversion rate and selectivity of the reaction reached over 90%, but the NaX molecular sieve had serious carbon deposition and a short service life.

[0007] In addition to using molecular sieves as catalysts for preparing anisole from methanol, Chinese Patent (CN 109879728 A) discloses using metal - non - metal composite oxides loaded with active components KF, CsF, NaF or CaF as catalysts. Among them, the metal oxides are oxides of Al, Cu, Zn, Co or Cr, and the non - metal oxide is silica. Using this catalyst, the efficient synthesis of anisole is achieved. The highest phenol conversion rate can reach 93.4%, and the selectivity of anisole is 99.7%. However, this catalyst has the problem of cumbersome preparation steps, and the patent does not investigate its service life. A literature (Zhang et al, Zeitschrift für Physikalische Chemie, 2010, 224(06), 857 - 864.) synthesized a mesoporous rare - earth phosphate and used it as a catalyst for preparing anisole from methanol, and studied its catalytic performance. Under 250 - 350 °C and nitrogen purging, the highest anisole selectivity can reach 100%. However, even when the molar ratio of phenol to methanol is 1:4, the phenol conversion rate is still low, and the catalyst service life is not investigated. An example of using sulfates as catalysts is shown in the literature (Pierantozzi et al, Applied Catalysis, 1986, 21(2) 263 - 271.). They studied the alkylation reaction of phenol with methanol catalyzed by La2(HPO4)3, BaSO4 and SrSO4. And the catalytic performance of BaSO4 in the liquid phase and gas phase at 300 °C was studied respectively. The results showed that BaSO4 in the liquid phase had higher catalytic reaction activity, with a selectivity of 98.9% and a phenol conversion rate of 30.3%; in the gas phase, there were only 7.1% conversion rate and 90.9% selectivity.

[0008] In summary, in the prior art, the synthesis methods of anisole still have problems such as low raw material conversion rate, low product selectivity, poor catalyst stability, and high reaction temperature. Summary of the Invention

[0009] In order to overcome the defects existing in the above-mentioned prior art, the present invention provides an alkylation catalyst, a preparation method and an application thereof. Using the alkylation catalyst to synthesize anisole has the advantages of high raw material conversion rate, high product selectivity, high catalyst stability, and mild reaction conditions.

[0010] In order to achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0011] An alkylation catalyst is a Mannich base-modified mesoporous titanium dioxide-supported iron-based spinel oxide catalyst;

[0012] The iron-based spinel oxide is any one of MgFe2O4, ZnFe2O4 or MnFe2O4;

[0013] The Mannich base includes but is not limited to 1-phenyl-3-anilino-1-propanone, 1-phenyl-3-benzylamino-1-propanone, 1-phenyl-3-diethylamino-1-propanone, 1-phenyl-3-(1-phenylethylamino)-1-propanone, 1-p-tolyl-3-benzylamino-1-propanone, 1-p-methoxyphenyl-3-benzylamino-1-propanone or 1-phenyl-3-p-toluidino-1-propanone.

[0014] Through the interaction between the N-H bond in the Mannich base and the oxygen atom in the catalyst, and the coordination complexation between the carbonyl group in the Mannich base and the metal ion in the catalyst, the stable combination of the Mannich base and the catalyst is realized.

[0015] Preferably, the mass ratio of Mannich base: mesoporous titanium dioxide: iron-based spinel is (2-3):100:(4-7.3).

[0016] The present invention also provides a preparation method of the alkylation catalyst, including the following steps:

[0017] Immerse mesoporous titanium dioxide in a soluble salt solution containing active components, adsorb at 70-95 °C for 4-8 h, filter and dry at 100 °C for 1-2 h, and calcine at 700-900 °C for 4-6 h to obtain a mesoporous titanium dioxide-supported iron-based spinel oxide catalyst; the soluble metal salt solution containing active components is a soluble salt of magnesium, zinc or manganese and a soluble iron salt mixed in a metal ion molar ratio of 1:2 and dissolved in water; (2) Add the mesoporous titanium dioxide-supported iron-based spinel oxide catalyst to the Mannich base solution, adsorb at 20-50 °C for 12-24 h, filter, and dry at 100-120 °C for 2-4 h to obtain an iron-based spinel oxide-supported Mannich base-modified mesoporous titanium dioxide catalyst.

[0018] Preferably, the soluble salts of magnesium, zinc or manganese in step (1) are nitrates, acetates or chlorides of magnesium, zinc or manganese, and the soluble iron salt is nitrate, acetate or chloride of iron.

[0019] Preferably, the mass ratio of the Mannich base in step (2), the mesoporous titanium dioxide in step (1) and the soluble metal salt in step (1) is (2-3):100:(6.3-20.2).

[0020] Preferably, the solvent of the Mannich base solution in step (2) is acetone.

[0021] Preferably, the concentration of the Mannich base in the Mannich base solution in step (2) is 0.02-0.03 g / mL.

[0022] The present invention also provides the application of the alkylation catalyst for catalyzing the synthesis of anisole. The method of the application includes the following steps:

[0023] Adding the alkylation catalyst into the mixed reaction system of methanol and phenol, heating and pressurizing for reaction to obtain a product;

[0024] The temperature of the reaction is 80-120 °C, and the pressure of the reaction is 0.2-0.4 MPa.

[0025] Preferably, the reaction time is 1-3 h. The reaction can be carried out in a reaction kettle or other reactors.

[0026] Preferably, the molar ratio of methanol to phenol is (1.0-3.05):1.

[0027] Preferably, the mass ratio of the alkylation catalyst to phenol is 2.6%-10.6%.

[0028] As a carrier, mesoporous titanium dioxide has a large specific surface area, stable chemical properties and is easy to be surface-modified. The iron-based spinel oxide can be well and uniformly loaded in the mesoporous titanium dioxide, which can well activate the phenolic hydroxyl group of phenol and methanol, and reduce the temperature of the phenol alkylation reaction. At the same time, the Mannich base has strong alkalinity and high compatibility with mesoporous titanium dioxide, can be stably loaded in the catalyst, can well activate the phenolic hydroxyl group, greatly reduce the reaction temperature, reduce the catalyst carbon deposition, and thus extend the service life of the catalyst.

[0029] Adopting the above technical solutions, compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The alkylation catalyst of the present invention is used for catalyzing the synthesis of anisole from methanol and phenol, and has the advantages of high catalytic activity, good reaction selectivity, a reaction conversion rate as high as 99% and a yield as high as 97%.

[0031] (2) The catalyst of the present invention has high catalytic efficiency and can achieve efficient and rapid synthesis of products at relatively low temperatures.

[0032] (3) The catalyst of the present invention has good stability and can be recycled multiple times or operated for a long period. Description of the Drawings

[0033] Figure 1 SEM image of the catalyst cat1 in Example 1;

[0034] Figure 2 Gas chromatogram of the filtrate in Application Example 1;

[0035] Figure 3 Gas chromatogram of the filtrate in Application Comparative Example 1;

[0036] Figure 4 Gas chromatogram of the catalytic reaction solution in Application Comparative Example 5;

[0037] Figure 5 Gas chromatogram of the filtrate in Application Example 2;

[0038] Figure 6 Gas chromatogram of the filtrate in Application Example 3. Specific Embodiments

[0039] The alkylation catalyst and the synthesis method of anisole provided by the present invention are further illustrated below through examples. However, the present invention is not limited thereto. For those skilled in the art, any equivalent substitution, modification, etc. should be included within the protection scope of the present invention.

[0040] Example 1

[0041] An alkylation catalyst, the preparation method of which comprises the following steps:

[0042] (1) Dissolve 2.97 g of magnesium nitrate and 9.7 g of iron nitrate in 200 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 90 °C for 5 hours, filter, dry at 100 °C for 1 hour, and calcine at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported magnesium ferrite oxide catalyst, and the magnesium ferrite is MgFe2O4.

[0043] (2) Add 2 g of Mannich base 1-phenyl-3-anilino-1-propanone to 100 mL of acetone to obtain a Mannich base solution. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 16 h, filter, and dry at 110 °C for 3 hours to obtain a modified mesoporous titanium dioxide-supported magnesium ferrite oxide catalyst Cat-1. The SEM image of Cat-1 is asFigure 1 As shown, it can be seen from the figure that the iron-based spinel oxide catalyst supported on modified mesoporous titanium dioxide is in the form of uniform particles, which is beneficial to the loading of the active components.

[0044] Example 2

[0045] An alkylation catalyst, and its preparation method includes the following steps:

[0046] (1) Dissolve 3.79 g of zinc nitrate and 9.7 g of iron nitrate in 200 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 90 °C for 5 hours, filter, dry at 100 °C for 1 hour, and calcine at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported zinc iron spinel oxide catalyst.

[0047] (2) Add 2 g of Mannich base 1-phenyl-3-anilino-1-propanone to 100 mL of acetone to obtain a Mannich base solution. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 16 hours, filter, and dry at 110 °C for 3 hours to obtain a modified mesoporous titanium dioxide-supported zinc iron spinel oxide catalyst Cat-2, and the zinc iron spinel is ZnFe2O4.

[0048] Example 3

[0049] An alkylation catalyst, and its preparation method includes the following steps:

[0050] (1) Dissolve 3.58 g of manganese nitrate and 9.7 g of iron nitrate in 200 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 90 °C for 5 hours, filter, dry at 100 °C for 1 hour, and calcine at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported manganese iron spinel oxide catalyst.

[0051] (2) Add 2 g of Mannich base 1-phenyl-3-anilino-1-propanone to 100 mL of acetone to obtain a Mannich base solution. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 16 hours, filter, and dry at 110 °C for 3 hours to obtain a modified mesoporous titanium dioxide-supported manganese iron spinel oxide catalyst Cat-3, and the manganese iron spinel is MnFe2O4.

[0052] Example 4

[0053] An alkylation catalyst, and its preparation method includes the following steps:

[0054] (1) Dissolve 1.48 g of magnesium nitrate and 4.84 g of iron nitrate in 100 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 90 °C for 4 hours, filter, dry at 100 °C for 1 hour, and calcine at 800 °C for 4 hours to obtain a mesoporous titanium dioxide-supported magnesium iron spinel oxide catalyst.

[0055] (2) Add 2 g of Mannich base 1-phenyl-3-anilino-1-propanone to 100 mL of acetone. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 16 hours, filter, and dry at 110 °C for 3 hours to obtain a modified mesoporous titanium dioxide-supported magnesium iron spinel oxide catalyst Cat-4, where the magnesium iron spinel is MgFe2O4.

[0056] Example 5

[0057] An alkylation catalyst, the preparation method of which comprises the following steps:

[0058] (1) Dissolve 1.48 g of magnesium nitrate and 4.84 g of iron nitrate in 100 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 90 °C for 4 hours, filter, dry at 100 °C for 1 hour, and calcine at 800 °C for 4 hours to obtain a mesoporous titanium dioxide-supported magnesium iron spinel oxide catalyst.

[0059] (2) Add 1 g of Mannich base 1-phenyl-3-anilino-1-propanone to 100 mL of acetone to obtain a Mannich base solution. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 12 hours, filter, and dry at 110 °C for 2 hours to obtain a modified mesoporous titanium dioxide-supported magnesium iron spinel oxide catalyst Cat-5, where the magnesium iron spinel is MgFe2O4.

[0060] Example 6

[0061] An alkylation catalyst, the preparation method of which comprises the following steps:

[0062] (1) Dissolve 2.97 g of magnesium nitrate and 9.7 g of iron nitrate in 200 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 90 °C for 5 hours, filter, dry at 100 °C for 1 hour, and calcine at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported magnesium iron spinel oxide catalyst.

[0063] (2) Add 2 g of Mannich base 1-phenyl-3-benzylamino-1-acetone to 100 mL of acetone to obtain a Mannich base solution. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 16 hours, filter, and dry at 110 °C for 3 hours to obtain a modified mesoporous titanium dioxide-supported magnesium ferrite oxide catalyst Cat-6, where the magnesium ferrite is MgFe₂O₄.

[0064] Example 7

[0065] An alkylation catalyst, and its preparation method includes the following steps:

[0066] (1) Dissolve 1.9 g of magnesium chloride and 8.0 g of iron sulfate in 200 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 95 °C for 5 hours, filter, dry at 100 °C for 2 hours, and calcine at 850 °C for 6 hours to obtain a mesoporous titanium dioxide-supported magnesium ferrite oxide catalyst.

[0067] (2) Add 2 g of Mannich base 1-phenyl-3-anilino-1-acetone to 100 mL of acetone to obtain a Mannich base solution. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 20 hours, filter, and dry at 100 °C for 4 hours to obtain a modified mesoporous titanium dioxide-supported magnesium ferrite oxide catalyst Cat-7, where the magnesium ferrite is MgFe₂O₄.

[0068] Example 8

[0069] An alkylation catalyst, and its preparation method includes the following steps:

[0070] (1) Dissolve 5.68 g of zinc nitrate and 14.51 g of iron nitrate in 300 mL of deionized water. Add 100 g of mesoporous titanium dioxide to this salt solution, stir at 90 °C for 6 hours, filter, dry at 100 °C for 1 hour, and calcine at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported magnesium ferrite oxide catalyst, where the magnesium ferrite is MgFe₂O₄.

[0071] (2) Add 2 g of Mannich base 1-phenyl-3-anilino-1-acetone to 100 mL of acetone to obtain a Mannich base solution. Add the catalyst prepared in step (1) to the above Mannich base solution, stir at 30 °C for 16 hours, filter, and dry at 110 °C for 3 hours to obtain a modified mesoporous titanium dioxide-supported magnesium ferrite oxide catalyst Cat-8.

[0072] Application Example 1

[0073] Add 5.0 g of Cat-1 to a 2 L reactor, then add 64.0 g of methanol and 94.1 g of phenol. Heat to 105 °C and stir, maintaining the pressure at 0.4 MPa. Stir for 1.5 hours and then stop the reaction. Cool to room temperature, release the pressure, filter the reactor liquid to recover the catalyst, and perform gas-phase detection on the filtrate. The gas chromatogram is as shown in Figure 2 shown. The conversion rate of phenol is 98.7%, the selectivity of anisole is 97.6%, and the yield is 96.3% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole with a finished product purity greater than 99.5%.

[0074] Application of Comparative Example 1

[0075] Add 2 g of Mannich base 1-phenyl-3-anilino-1-propanone to a 2 L reactor, then add 64.0 g of methanol and 94.1 g of phenol. Heat to 105 °C and stir, maintaining the pressure at 0.4 MPa. Stir for 2.0 hours and then stop the reaction. Cool to room temperature, release the pressure, filter the reactor liquid to recover the catalyst, and perform gas-phase detection on the filtrate. The gas chromatogram is as shown in Figure 3 shown. The conversion rate of phenol is 52.2%, the selectivity of anisole is 97.6%, and the yield is 50.9% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole with a finished product purity greater than 99.5%.

[0076] Application of Comparative Example 2

[0077] Add 5 g of mesoporous titanium dioxide to a 2 L reactor, then add 64.0 g of methanol and 94.1 g of phenol. Heat to 105 °C and stir, maintaining the pressure at 0.4 MPa. Stir for 2.0 hours and then stop the reaction. Cool to room temperature, release the pressure, filter the reactor liquid to recover the catalyst, and perform gas-phase detection on the filtrate. The conversion rate of phenol is 5.8%, the selectivity of anisole is 98.0%, and the yield is 5.7% (calculated based on phenol).

[0078] Application of Comparative Example 3

[0079] Add 5 g of the prepared magnesium ferrite spinel to a 2 L reactor, then add 64.0 g of methanol and 94.1 g of phenol. Heat to 105 °C and stir, maintaining the pressure at 0.4 MPa. Stir for 2.0 h and then stop the reaction. Cool to room temperature, release the pressure, filter the reactor liquid to recover the catalyst, and perform gas-phase detection on the filtrate. The conversion rate of phenol is 13.9%, the selectivity of anisole is 97.1%, and the yield is 13.5% (calculated based on phenol).

[0080] Application of Comparative Example 4

[0081] Add 0.13 g of magnesium nitrate, 0.42 g of iron nitrate, 4.36 g of mesoporous titanium dioxide, and 0.09 g of Mannich base 1-phenyl-3-anilino-1-propanone to a reaction kettle. Add 64.0 g of methanol and 94.1 g of phenol, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 2.0 hours, stop the reaction, cool to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, and conduct gas-phase detection on the filtrate. The conversion rate of phenol is 63.7%, the selectivity of anisole is 97.3%, and the yield is 62.0% (calculated based on phenol).

[0082] Application Comparative Example 5

[0083] Add 64.0 g of methanol and 94.1 g of phenol to a reaction kettle, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 2.0 hours, stop the reaction, cool to room temperature, relieve the pressure, and conduct gas-phase detection on the catalytic reaction liquid. The results are as Figure 4 shown. The conversion rate of phenol is 0%, and the yield is 0% (calculated based on phenol).

[0084] Application Example 2

[0085] Add 5.0 g of Cat-1 to a 2 L reaction kettle, add 64.0 g of methanol and 94.1 g of phenol, heat to 105 °C and stir, maintain the pressure at 0.2 MPa, stir for 3.0 hours, stop the reaction, cool to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, and conduct gas-phase detection on the filtrate. The gas chromatogram is as Figure 5 shown. The conversion rate is 97.3%, the selectivity is 97.4%, and the yield is 94.8% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole finished product with a purity greater than 99.5%.

[0086] Application Example 3

[0087] Add 10.0 g of Cat-1 to a 2 L reaction kettle, add 64.0 g of methanol and 94.1 g of phenol, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 1.0 hours, stop the reaction, cool to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, and conduct gas-phase detection on the filtrate. The gas chromatogram is as Figure 6 shown. The conversion rate is 99.4%, the selectivity is 93.3%, and the yield is 92.8% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole finished product with a purity greater than 99.5%.

[0088] Application Example 4

[0089] Add 2.5 g of Cat-1 to a 2 L reaction kettle, add 64.0 g of methanol and 94.1 g of phenol, heat to 110 °C and stir, maintain the pressure at 0.4 MPa, stir for 3.0 hours to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 93.6%, the selectivity is 97.8%, and the yield is 91.5% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole finished product with a purity of more than 99.5%.

[0090] Application Example 5

[0091] Add 5.0 g of Cat-2 to a 2 L reaction kettle, add 64.0 g of methanol and 94.1 g of phenol, heat to 110 °C and stir, maintain the pressure at 0.4 MPa, stir for 2.0 hours to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 91.2%, the selectivity is 92.8%, and the yield is 84.6% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole finished product with a purity of more than 99.5%.

[0092] Application Example 6

[0093] Add 5.0 g of Cat-3 to a 2 L reaction kettle, add 64.0 g of methanol and 94.1 g of phenol, heat to 100 °C and stir, maintain the pressure at 0.4 MPa, stir for 1.0 hour to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 99.4%, the selectivity is 86.4%, and the yield is 85.9% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole finished product with a purity of more than 99.5%.

[0094] Application Example 7

[0095] Add 5.0 g of Cat-4 to a 2 L reaction kettle, add 64.0 g of methanol and 94.1 g of phenol, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 3.0 h to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 88.5%, the selectivity is 97.6%, and the yield is 86.4% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole finished product with a purity of more than 99.5%.

[0096] Application Example 8

[0097] Add 5.0 g of Cat-5 into a 2 L reactor, add 64.0 g of methanol and 94.1 g of phenol, heat to 110 °C and stir, maintain the pressure at 0.4 MPa, stir for 3.0 hours to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 82.7%, the selectivity is 97.1%, and the yield is 80.3% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole product with a purity of more than 99.5%.

[0098] Application Example 9

[0099] Add 5.0 g of Cat-6 into a 2 L reactor, add 64.0 g of methanol and 94.1 g of phenol, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 1.0 hour to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 97.0%, the selectivity is 99.1%, and the yield is 96.1% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole product with a purity of more than 99.5%.

[0100] Application Example 10

[0101] Add 5.0 g of Cat-7 into a 2 L reactor, add 64.0 g of methanol and 94.1 g of phenol, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 1.0 hour to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 98.9%, the selectivity is 95.4%, and the yield is 94.4% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole product with a purity of more than 99.5%.

[0102] Application Example 11

[0103] Add 5.0 g of Cat-8 into a 2 L reactor, add 64.0 g of methanol and 94.1 g of phenol, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 1.0 hour to stop the reaction, cool down to room temperature, relieve the pressure, filter the kettle liquid to recover the catalyst, detect the filtrate by gas phase, the conversion rate is 94.7%, the selectivity is 93.9%, and the yield is 88.9% (calculated based on phenol). Recover methanol by atmospheric distillation and obtain anisole product with a purity of more than 99.5%.

[0104] Application Example 12

[0105] 5.0 g of Cat-1 was added to a 2 L reactor, 32.0 g of methanol and 94.1 g of phenol were added, heated to 110 °C and stirred, maintaining the pressure at 0.4 MPa. Stirring was stopped after 3.0 hours, the temperature was lowered to room temperature, the pressure was released, the catalyst was recovered by filtering the kettle liquid, and the filtrate was detected by gas phase. The conversion rate was 75.0%, the selectivity was 95.8%, and the yield was 71.9% (calculated based on phenol). The product anisole with a purity greater than 99.5% was obtained by atmospheric distillation.

[0106] Application Example 13

[0107] The recovered catalyst in Application Example 1 was reused. The recovered Cat-1 was added to a 2 L reactor, 64.0 g of methanol and 94.1 g of phenol were added, heated to 105 °C and stirred, maintaining the pressure at 0.4 MPa. Stirring was stopped after 1.0 hour, the temperature was lowered to room temperature, the pressure was released, the catalyst was recovered by filtering the kettle liquid, and the filtrate was detected by gas phase. The conversion rate was 99.5%, the selectivity was 96.4%, and the yield was 95.9% (calculated based on phenol). Methanol was recovered by atmospheric distillation, and the product anisole with a purity greater than 99.5% was obtained.

[0108] The above process was repeated, and Cat-1 was reused 10 times. The average conversion rate was 97.2%, the average selectivity was 96.5%, and the average yield was 93.8%.

[0109] The reused catalyst was calcined and activated, and could be restored to its initial catalytic activity after being modified with Mannich base again.

Claims

1. An alkylation catalyst, characterized in that, It is a Fe-based spinel oxide catalyst supported by Mannich base modified mesoporous titanium dioxide; The Fe-based spinel oxide is any one of MgFe2O4, ZnFe2O4 or MnFe2O4; The Mannich base is 1-phenyl-3-anilino-1-propanone or 1-phenyl-3-benzylamino-1-propanone; The mass ratio of Mannich base: mesoporous titanium dioxide: Fe-based spinel is (2-3):100:(4-7.3).

2. The preparation method of the alkylation catalyst according to claim 1, characterized in that, It includes the following steps: (1) Immerse the mesoporous titanium dioxide in a soluble salt solution containing active components, adsorb at 70-95 °C for 4-8 h, filter and dry at 100 °C for 1-2 hours, and calcine at 700-900 °C for 4-6 hours to obtain a Fe-based spinel oxide catalyst supported by mesoporous titanium dioxide; the soluble metal salt solution containing active components is obtained by mixing soluble salts of magnesium, zinc or manganese and soluble iron salts in a metal ion molar ratio of 1:2 and dissolving them in water; (2) Add the Fe-based spinel oxide catalyst supported by mesoporous titanium dioxide into the Mannich base solution, adsorb at 20-50 °C for 12-24 h, filter, and dry at 100-120 °C for 2-4 hours to obtain a Mannich base modified mesoporous titanium dioxide catalyst supported by Fe-based spinel oxide.

3. The preparation method of the alkylation catalyst according to claim 2, characterized in that, In step (1), the soluble salts of magnesium, zinc or manganese are nitrates, acetates or chlorides of magnesium, zinc or manganese, and the soluble iron salt is a nitrate, acetate or chloride of iron.

4. The preparation method of the alkylation catalyst according to claim 3, characterized in that, In step (2), the mass ratio of the Mannich base, the mesoporous titanium dioxide in step (1) and the soluble metal salt in step (1) is (2-3):100:(6.3-20.2).

5. The preparation method of the alkylation catalyst according to claim 3, characterized in that, In step (2), the solvent of the Mannich base solution is acetone; the concentration of the Mannich base in the Mannich base solution is 0.02-0.03 g / mL.

6. Use of the alkylation catalyst according to claim 1, characterized in that, It is used for catalytic synthesis of anisole, and the method of the application includes the following steps: Add the alkylation catalyst into the mixed reaction system of methanol and phenol, heat and pressurize the reaction to obtain the product; The temperature of the reaction is 80-120 °C, and the pressure of the reaction is 0.2-0.4 MPa.

7. Use of the alkylation catalyst according to claim 6, characterized in that, The reaction time is 1-3 h.

8. Use of the alkylation catalyst according to claim 6, characterized in that, The molar ratio of methanol to phenol is (1.0-3.05):

1.

9. Use of the alkylation catalyst according to claim 6, characterized in that, The mass ratio of the alkylation catalyst to phenol is 2.6%-10.6%.

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