Alkylation catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of organic synthesis catalysts, in particular to an alkylation catalyst and a preparation method and application thereof. The alkylation catalyst provided by the invention is an iron-based spinel oxide catalyst loaded by Mannich base modified mesoporous titanium dioxide. The mesoporous titanium dioxide is used as a carrier, the iron-based spinel oxide can be well and uniformly loaded in the mesoporous titanium dioxide, and the Mannich base has strong alkalinity, has high compatibility with the mesoporous titanium dioxide, can be stably loaded in the catalyst, and can well activate phenolic hydroxyl groups, greatly reduce the reaction temperature and reduce the carbon deposition of the catalyst. The service life of the catalyst is prolonged. The catalyst has the following advantages: the catalyst is high in catalytic activity and good in reaction selectivity, the reaction conversion rate is as high as 99%, and the yield is as high as 97%; the catalytic efficiency is high, and efficient and rapid synthesis of a product can be realized at a relatively low temperature; the stability is good, and multi-time cyclic utilization or long-period operation can be realized.

Description

Technical Field

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

[0002] Anisole, also known as anisole, methoxy ether, and methyl phenyl ether, has a wide range of applications in the fields of photosensitizers, dyes, medicines, pesticides, and spices. For example, it is often used in the synthesis of beer antioxidants, plastic stabilizers, and ethylene polymer UV stabilizers; or as a primary raw material for the production of spices, pesticides, and dyes, or to increase the octane number of gasoline.

[0003] Anisole is prepared from 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 stability of conjugate base, the OH bond on the phenyl ring is easy to break. Although the alkylating agent is susceptible to the attack of the oxygen atom in the hydroxyl in the reaction process, it is also susceptible to the attack of the electrons on the phenyl ring, therefore, the hydroxyl in the phenol is easily directed to the ortho and para positions by the electrophilic reagent, and in the phenol alkylation process, except that anisole may also form various by-products such as cresol, substituted anisole, dimethylphenol or trimethylphenol, so in order to improve the selectivity and productive rate of anisole in the prior art, acid-base catalyst is usually adopted as the catalyst of this electrophilic substitution reaction. And research finds that the orientation of phenol on catalyst surface, the type of methylating agent, reaction conditions, acid-base strength, the deactivation rate of catalyst may all become the important factor affecting the selectivity and productive rate of anisole.

[0004] In the prior art, the alkylation reaction of phenol to synthesize anisole mainly uses dimethyl sulfate (DMS), iodomethane (Iodomethane), dimethyl carbonate (DMC), and methanol as methylating agents, among which dimethyl sulfate and iodomethane have high reactivity and can react with phenol ions in the liquid phase at room temperature or slightly above room temperature, and obtain a very high conversion rate. At present, the dimethyl sulfate process is mainly used in China to produce anisole, but this process will produce difficult-to-treat phenol-containing wastewater; and dimethyl sulfate is a highly toxic chemical, which limits the application of this process. Iodomethane is expensive and it is difficult to achieve large-scale production as a methylating agent. Although dimethyl carbonate is green and environmentally friendly, it is also expensive and is not suitable for large-scale industrial production of anisole. Methanol is used as a methylating agent to react with phenol to synthesize anisole, which has the potential advantages of low raw material cost and simple post-processing.

[0005] Currently, there are a variety of catalytic systems for preparing anisole using methanol as a methylating agent, such as molecular sieves, metal oxides, phosphates, sulfates, and other solid acid-base catalysts.

[0006] In the prior art, there is a document (Balsama et al, Applied Catalysis, 1984, 13, 161-170.) that compares several zeolite molecular sieves (X, Y, ZSM type) to evaluate their reactivity, stability and distribution of alkylation products, etc. The results show that the conversion rate is low when the catalytic reaction is carried out at a lower temperature. Another document (Kirichenko et al, Petroleum Chemistry, 2008, 48, 389-392.) reports that the synthesis of anisole from phenol and methanol was achieved using NaX molecular sieve as a catalyst. Under certain conditions, the conversion rate and selectivity of the reaction reached more than 90%, but the NaX molecular sieve has the problem of severe carbon deposition and short life.

[0007] In addition to using molecular sieves as catalysts for preparing anisole from methanol, a Chinese patent (CN 109879728 A) discloses using metal-nonmetal composite oxides loaded with active components KF, CsF, NaF or CaF as catalysts, wherein the metal oxides are oxides of Al, Cu, Zn, Co or Cr, and the nonmetal oxides are white carbon black. The catalysts are used to achieve efficient synthesis of anisole, with a phenol conversion rate of up to 93.4% and anisole selectivity of 99.7%. However, the catalyst has the problem of cumbersome preparation steps, and the patent does not investigate its lifespan. The 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. At 250-350 °C and nitrogen purge, the selectivity of anisole can reach up to 100%, but even when the molar ratio of phenol to methanol is 1:4, the phenol conversion rate is still low, and the catalyst life is not investigated. The example of sulfate as a catalyst is reflected in the literature (Pierantozzi et al, Applied Catalysis, 1986, 21 (2) 263-271.), which studied the alkylation reaction of phenol and methanol catalyzed by La2(HPO4)3, BaSO4 and SrSO4. The catalytic performance of BaSO4 in liquid and gas phases at 300 °C was studied respectively. The results showed that BaSO4 in the liquid phase had a high catalytic reaction activity, with a selectivity of 98.9% and a phenol conversion rate of 30.3%; in the gas phase, it only had a conversion rate of 7.1% and a selectivity of 90.9%.

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

[0009] In order to overcome the defects of the above-mentioned prior art, the present invention provides an alkylation catalyst and a preparation method and application thereof. The alkylation catalyst is used to synthesize anisole, which 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 object of the invention, the present invention provides the following technical solutions: An alkylation catalyst is an iron-based spinel oxide catalyst supported by Mannich base-modified mesoporous titanium dioxide; The iron-based spinel oxide is any one of MgFe2O4, ZnFe2O4 or MnFe2O4; 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-tolylpropan-3-benzylamino-1-propanone, 1-p-methoxyphenyl-3-benzylamino-1-propanone or 1-phenyl-3-p-toluidin-1-propanone.

[0011] The stable combination of the Mannich base and the catalyst is achieved through the interaction between the NH bond in the Mannich base and the oxygen atom in the catalyst, as well as the coordination and complexation between the carbonyl group in the Mannich base and the metal ion in the catalyst.

[0012] Preferably, the mass ratio of Mannich base: mesoporous titanium dioxide: iron-based spinel is (2-3):100:(4-7.3). The present invention also provides a method for preparing the alkylation catalyst, comprising the following steps: The mesoporous titanium dioxide is immersed in a soluble salt solution containing an active component, adsorbed at 70-95°C for 4-8 hours, filtered, dried at 100°C for 1-2 hours, and calcined at 700-900°C for 4-6 hours to obtain a mesoporous titanium dioxide-supported iron-based spinel oxide catalyst; the soluble metal salt solution containing the active component is a mixture of a soluble salt of magnesium, zinc or manganese and a soluble iron salt in a metal ion molar ratio of 1:2 and dissolved in water; (2) the mesoporous titanium dioxide-supported iron-based spinel oxide catalyst is added to a Mannich base solution, adsorbed at 20-50°C for 12-24 hours, filtered, and dried at 100-120°C for 2-4 hours to obtain a Mannich base-modified mesoporous titanium dioxide catalyst supported by an iron-based spinel oxide.

[0013] Preferably, the soluble salt of magnesium, zinc or manganese in step (1) is a nitrate, acetate or chloride of magnesium, zinc or manganese, and the soluble iron salt is a nitrate, acetate or chloride of iron.

[0014] 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).

[0015] Preferably, the solvent of the Mannich base solution in step (2) is acetone.

[0016] Preferably, the concentration of the Mannich base in the Mannich base solution in step (2) is 0.02-0.03 g / mL.

[0017] The present invention also provides an application of the alkylation catalyst for catalytic synthesis of anisole, wherein the application method comprises the following steps: Adding the alkylation catalyst into a mixed reaction system of methanol and phenol, heating and pressurizing the system to react, and obtaining a product; The reaction temperature is 80-120° C., and the reaction pressure is 0.2-0.4 MPa.

[0018] Preferably, the reaction time is 1-3 h. The reaction can be carried out in a reactor or other reactors.

[0019] Preferably, the molar ratio of methanol to phenol is (1.0-3.05):1.

[0020] Preferably, the mass ratio of the alkylation catalyst to phenol is 2.6%-10.6%.

[0021] Mesoporous titanium dioxide as a carrier has a large specific surface area, stable chemical properties, and is easy to modify on the surface. Iron-based spinel oxide can be well and evenly loaded in mesoporous titanium dioxide, which can well activate the phenolic hydroxyl groups of phenol and methanol, and reduce the reaction temperature of phenol alkylation. At the same time, Mannich base has strong alkalinity and high compatibility with mesoporous titanium dioxide. It can be stably loaded in the catalyst, which can well activate the phenolic hydroxyl groups, greatly reduce the reaction temperature, reduce catalyst carbon deposition, and thus extend the service life of the catalyst.

[0022] The present invention adopts the above technical solution, which has the following beneficial effects compared with the prior art: (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 of up to 99%, and a yield of up to 97%.

[0023] (2) The catalyst of the present invention has high catalytic efficiency and can achieve efficient and rapid synthesis of products at a relatively low temperature.

[0024] (3) The catalyst of the present invention has good stability and can be recycled multiple times or operated for a long period of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a SEM image of the catalyst cat1 in Example 1; Figure 2 is the gas phase spectrum of the filtrate in Application Example 1; Figure 3 The gas phase spectrum of the filtrate in Comparative Example 1 is shown; Figure 4 The gas phase spectrum of the catalytic reaction liquid in Comparative Example 5; Figure 5 is the gas phase spectrum of the filtrate in Application Example 2; Figure 6 This is the gas phase spectrum of the filtrate in Application Example 3. DETAILED DESCRIPTION

[0026] The following examples further illustrate the alkylation catalyst and the synthesis method of anisole provided by the present invention, but the present invention is not limited thereto. For those skilled in the art, any equivalent substitutions, modifications, etc. made should be included in the protection scope of the present invention.

[0027] Example 1 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 2.97 g of magnesium nitrate and 9.7 g of ferric nitrate were dissolved in 200 mL of deionized water, 100 g of mesoporous titanium dioxide was added to the salt solution, and the mixture was stirred at 90 °C for 5 hours. After filtering, the mixture was dried at 100 °C for 1 hour and calcined at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported magnesia-iron spinel oxide catalyst, wherein the magnesia-iron spinel is MgFe2O4.

[0028] (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 iron spinel oxide catalyst Cat-1. The SEM image of Cat-1 is shown in FIG. Figure 1 As shown in the figure, it can be seen that the iron-based spinel oxide catalyst supported by the modified mesoporous titanium dioxide is in a uniform granular form, which is conducive to the loading of active components.

[0029] Example 2 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 3.79 g zinc nitrate and 9.7 g ferric nitrate were dissolved in 200 mL deionized water, 100 g mesoporous titanium dioxide was added to the salt solution, stirred at 90 °C for 5 hours, filtered, dried at 100 °C for 1 hour, and calcined at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported zinc-iron spinel oxide catalyst.

[0030] (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, wherein the zinc iron spinel is ZnFe2O4.

[0031] Example 3 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 3.58 g of manganese nitrate and 9.7 g of ferric nitrate were dissolved in 200 mL of deionized water, 100 g of mesoporous titanium dioxide was added to the salt solution, stirred at 90 °C for 5 hours, filtered, dried at 100 °C for 1 hour, and calcined at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported manganese-iron spinel oxide catalyst.

[0032] (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, wherein the manganese iron spinel is MnFe2O4.

[0033] Example 4 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 1.48 g of magnesium nitrate and 4.84 g of ferric nitrate were dissolved in 100 mL of deionized water, 100 g of mesoporous titanium dioxide was added to the salt solution, stirred at 90 °C for 4 hours, filtered, dried at 100 °C for 1 hour, and calcined at 800 °C for 4 hours to obtain a mesoporous titanium dioxide-supported magnesium-iron spinel oxide catalyst.

[0034] (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 ferromagnesian spinel oxide catalyst Cat-4, wherein the ferromagnesian spinel is MgFe2O4.

[0035] Example 5 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 1.48 g of magnesium nitrate and 4.84 g of ferric nitrate were dissolved in 100 mL of deionized water, 100 g of mesoporous titanium dioxide was added to the salt solution, stirred at 90 °C for 4 hours, filtered, dried at 100 °C for 1 hour, and calcined at 800 °C for 4 hours to obtain a mesoporous titanium dioxide-supported magnesium-iron spinel oxide catalyst.

[0036] (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 ferromagnesian spinel oxide catalyst Cat-5, wherein the ferromagnesian spinel is MgFe2O4.

[0037] Example 6 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 2.97 g of magnesium nitrate and 9.7 g of ferric nitrate were dissolved in 200 mL of deionized water, 100 g of mesoporous titanium dioxide was added to the salt solution, stirred at 90 °C for 5 hours, filtered, dried at 100 °C for 1 hour, and calcined at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported magnesium-iron spinel oxide catalyst.

[0038] (2) Add 2 g of Mannich base 1-phenyl-3-benzylamino-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 ferromagnesium spinel oxide catalyst Cat-6, wherein the ferromagnesium spinel is MgFe2O4.

[0039] Example 7 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 1.9 g of magnesium chloride and 8.0 g of ferric sulfate were dissolved in 200 mL of deionized water, 100 g of mesoporous titanium dioxide was added to the salt solution, stirred at 95 °C for 5 hours, filtered, dried at 100 °C for 2 hours, and calcined at 850 °C for 6 hours to obtain a mesoporous titanium dioxide-supported magnesium-iron spinel oxide catalyst.

[0040] (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 20 hours, filter, and dry at 100°C for 4 hours to obtain a modified mesoporous titanium dioxide-supported ferromagnesian spinel oxide catalyst Cat-7, wherein the ferromagnesian spinel is MgFe2O4.

[0041] Example 8 An alkylation catalyst, the preparation method of which comprises the following steps: (1) 5.68 g of zinc nitrate and 14.51 g of ferric nitrate were dissolved in 300 mL of deionized water, 100 g of mesoporous titanium dioxide was added to the salt solution, and the mixture was stirred at 90 °C for 6 hours. After filtering, the mixture was dried at 100 °C for 1 hour and calcined at 800 °C for 5 hours to obtain a mesoporous titanium dioxide-supported magnesia-iron spinel oxide catalyst, wherein the magnesia-iron spinel is MgFe2O4.

[0042] (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 magnesium-iron spinel oxide catalyst Cat-8. Application Example 1 Add 5.0 g Cat-1 into a 2 L reactor, add 64.0 g methanol and 94.1 g phenol, heat to 105 ° C and stir, maintain the pressure at 0.4 MPa, stir for 1.5 hours to stop the reaction, cool to room temperature, release the pressure, filter the kettle liquid to recover the catalyst, and perform gas phase detection on the filtrate. The gas phase spectrum is as follows: Figure 2 As shown in the figure, the phenol conversion rate is 98.7%, the anisole selectivity is 97.6%, the yield is 96.3% (based on phenol), methanol is recovered by atmospheric distillation, and anisole finished product with a purity greater than 99.5% is obtained.

[0043] Application Comparative Example 1 2 g of Mannich base 1-phenyl-3-anilino-1-propanone was added to a 2 L reactor, and 64.0 g of methanol and 94.1 g of phenol were added. The mixture was heated to 105 °C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 2.0 hours. The mixture was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The gas phase spectrum was as shown in FIG. Figure 3 As shown in the figure, the phenol conversion rate is 52.2%, the anisole selectivity is 97.6%, the yield is 50.9% (based on phenol), methanol is recovered by atmospheric pressure distillation, and anisole finished product with a purity greater than 99.5% is obtained.

[0044] Application Comparative Example 2 5 g of mesoporous titanium dioxide was added to a 2 L reactor, and 64.0 g of methanol and 94.1 g of phenol were added. The reaction was heated to 105 °C and stirred. The pressure was maintained at 0.4 MPa and the reaction was stopped after stirring for 2.0 hours. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the kettle liquid. The filtrate was tested by gas phase detection. The conversion rate of phenol was 5.8%, the selectivity of anisole was 98.0%, and the yield was 5.7% (based on phenol).

[0045] Application Comparative Example 3 5 g of the prepared magnesium iron spinel was added to a 2 L reactor, and 64.0 g of methanol and 94.1 g of phenol were added. The reaction was heated to 105 °C and stirred. The pressure was maintained at 0.4 MPa and stirred for 2.0 h to stop the reaction. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the kettle liquid. The filtrate was tested by gas phase detection. The conversion rate of phenol was 13.9%, the selectivity of anisole was 97.1%, and the yield was 13.5% (based on phenol).

[0046] Application Comparative Example 4 0.13 g of magnesium nitrate, 0.42 g of ferric nitrate, 4.36 g of mesoporous titanium dioxide and 0.09 g of Mannich base 1-phenyl-3-anilino-1-propanone were placed in a reaction kettle, and 64.0 g of methanol and 94.1 g of phenol were added. The mixture was heated to 105 °C and stirred. The pressure was maintained at 0.4 MPa and the reaction was stopped after stirring for 2.0 hours. The mixture was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the kettle liquid. The filtrate was tested by gas phase. The conversion rate of phenol was 63.7%, the selectivity of anisole was 97.3%, and the yield was 62.0% (based on phenol).

[0047] Application Comparative Example 5 Add 64.0 g methanol and 94.1 g phenol to the reactor, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 2.0 hours to stop the reaction, cool to room temperature, release the pressure, and perform gas phase detection on the catalytic reaction liquid. The results are as follows: Figure 4 As shown in the figure, the phenol conversion rate is 0% and the yield is 0% (based on phenol).

[0048] Application Example 2 5.0 g Cat-1 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The mixture was heated to 105°C and stirred. The pressure was maintained at 0.2 MPa. The reaction was stopped after stirring for 3.0 hours. The mixture was cooled to room temperature and depressurized. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The gas phase spectrum was as shown in FIG. Figure 5 As shown in the figure, the conversion rate is 97.3%, the selectivity is 97.4%, the yield is 94.8% (based on phenol), methanol is recovered by atmospheric pressure distillation, and anisole product with a purity greater than 99.5% is obtained.

[0049] Application Example 3 Add 10.0 g Cat-1 into a 2 L reactor, add 64.0 g methanol and 94.1 g phenol, heat to 105 °C and stir, maintain the pressure at 0.4 MPa, stir for 1.0 hour to 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 phase spectrum is as shown in Figure 6 As shown in the figure, the conversion rate is 99.4%, the selectivity is 93.3%, the yield is 92.8% (based on phenol), methanol is recovered by atmospheric pressure distillation, and anisole product with a purity greater than 99.5% is obtained.

[0050] Application Example 4 2.5 g Cat-1 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 110°C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 3.0 hours. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The conversion rate was 93.6%, the selectivity was 97.8%, and the yield was 91.5% (based on phenol). Methanol was recovered by distillation at normal pressure, and a finished anisole product with a purity greater than 99.5% was obtained.

[0051] Application Example 5 5.0 g Cat-2 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 110°C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 2.0 hours. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The conversion rate was 91.2%, the selectivity was 92.8%, and the yield was 84.6% (based on phenol). Methanol was recovered by distillation at normal pressure, and a finished anisole product with a purity greater than 99.5% was obtained.

[0052] Application Example 6 5.0 g Cat-3 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 100°C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 1.0 hour. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested by gas phase. The conversion rate was 99.4%, the selectivity was 86.4%, and the yield was 85.9% (based on phenol). Methanol was recovered by atmospheric distillation, and a finished anisole product with a purity greater than 99.5% was obtained.

[0053] Application Example 7 5.0 g Cat-4 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 105 °C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 3.0 h. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested by gas phase. The conversion rate was 88.5%, the selectivity was 97.6%, and the yield was 86.4% (based on phenol). Methanol was recovered by atmospheric distillation, and a finished anisole product with a purity greater than 99.5% was obtained.

[0054] Application Example 8 5.0 g Cat-5 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 110°C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 3.0 hours. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The conversion rate was 82.7%, the selectivity was 97.1%, and the yield was 80.3% (based on phenol). Methanol was recovered by distillation at normal pressure, and a finished anisole product with a purity greater than 99.5% was obtained.

[0055] Application Example 9 5.0 g Cat-6 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 105°C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 1.0 hour. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The conversion rate was 97.0%, the selectivity was 99.1%, and the yield was 96.1% (based on phenol). Methanol was recovered by distillation at normal pressure, and a finished anisole product with a purity greater than 99.5% was obtained.

[0056] Application Example 10 5.0 g Cat-7 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 105°C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 1.0 hour. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The conversion rate was 98.9%, the selectivity was 95.4%, and the yield was 94.4% (based on phenol). Methanol was recovered by atmospheric distillation, and a finished anisole product with a purity greater than 99.5% was obtained.

[0057] Application Example 11 5.0 g Cat-8 was added to a 2 L reactor, and 64.0 g methanol and 94.1 g phenol were added. The reaction was heated to 105 °C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 1.0 hour. The reaction was cooled to room temperature and the pressure was released. The catalyst was recovered by filtering the reactor liquid. The filtrate was tested for gas phase. The conversion rate was 94.7%, the selectivity was 93.9%, and the yield was 88.9% (based on phenol). Methanol was recovered by atmospheric distillation, and a finished anisole product with a purity greater than 99.5% was obtained.

[0058] Application Example 12 5.0 g Cat-1 was added to a 2 L reactor, and 32.0 g methanol and 94.1 g phenol were added. The reaction was heated to 110°C and stirred. The pressure was maintained at 0.4 MPa. The reaction was stopped after stirring for 3.0 hours. The reaction was cooled to room temperature, the pressure was released, and the catalyst was recovered by filtering the kettle liquid. The filtrate was tested for gas phase. The conversion rate was 75.0%, the selectivity was 95.8%, and the yield was 71.9% (based on phenol). The anisole product with a purity greater than 99.5% was obtained by distillation at normal pressure.

[0059] Application Example 13 The catalyst recovered in Application Example 1 was applied, and the recovered Cat-1 was added to a 2 L reactor, and 64.0 g of methanol and 94.1 g of phenol were added. The reaction was heated to 105 ° C and stirred. The pressure was maintained at 0.4 MPa, and the reaction was stopped after stirring for 1.0 hour. The temperature was cooled to room temperature, the pressure was released, and the catalyst was recovered by filtering the kettle liquid. The filtrate was tested for gas phase. The conversion rate was 99.5%, the selectivity was 96.4%, and the yield was 95.9% (based on phenol). Methanol was recovered by atmospheric distillation, and a finished anisole product with a purity greater than 99.5% was obtained.

[0060] The above process was repeated and Cat-1 was applied 10 times, with an average conversion rate of 97.2%, an average selectivity of 96.5%, and an average yield of 93.8%.

[0061] The catalyst can be activated by calcination and then restored to its initial catalytic activity after being modified by Mannich base.

Claims

1. An alkylation catalyst, characterized in that It is a Mannich base modified mesoporous titanium dioxide supported iron-based spinel oxide catalyst; The iron-based spinel oxide is any one of MgFe2O4, ZnFe2O4 or MnFe2O4; 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-tolylpropan-3-benzylamino-1-propanone, 1-p-methoxyphenyl-3-benzylamino-1-propanone or 1-phenyl-3-p-toluidin-1-propanone.

2. The alkylation catalyst according to claim 1, characterized in that The mass ratio of Mannich base: mesoporous titanium dioxide: iron-based spinel is (2-3):100:(4-7.3).

3. The method for preparing an alkylation catalyst according to claim 1 or 2, characterized in that: The following steps are involved: (1) Immersing mesoporous titanium dioxide in a soluble salt solution containing an active component, adsorbing at 70-95°C for 4-8 hours, filtering and drying at 100°C for 1-2 hours, and calcining at 700-900°C for 4-6 hours to obtain a mesoporous titanium dioxide-supported iron-based spinel oxide catalyst; the soluble metal salt solution containing the active component is a mixture of a soluble salt of magnesium, zinc or manganese and a soluble iron salt in a metal ion molar ratio of 1:2 dissolved in water; (2) Adding the iron-based spinel oxide catalyst supported by mesoporous titanium dioxide into a Mannich base solution, adsorbing at 20-50° C. for 12-24 h, filtering, and drying at 100-120° C. for 2-4 hours to obtain a Mannich base-modified mesoporous titanium dioxide catalyst supported by iron-based spinel oxide.

4. The method for preparing the alkylation catalyst according to claim 3, characterized in that: In step (1), the soluble salt of magnesium, zinc or manganese is nitrate, acetate or chloride of magnesium, zinc or manganese, and the soluble iron salt is nitrate, acetate or chloride of iron.

5. The method for preparing the alkylation catalyst according to claim 4, characterized in that: 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).

6. The method for preparing the alkylation catalyst according to claim 4, characterized in that: The solvent of the Mannich base solution in step (2) is acetone; the concentration of the Mannich base in the Mannich base solution is 0.02-0.03 g / mL.

7. The use of the alkyl catalyst according to claim 1 or 2, characterized in that: Used for catalytic synthesis of anisole, the application method comprises the following steps: Adding the alkylation catalyst into a mixed reaction system of methanol and phenol, heating and pressurizing the system to react, and obtaining a product; The reaction temperature is 80-120° C., and the reaction pressure is 0.2-0.4 MPa.

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

9. The use of the alkylation catalyst according to claim 7, characterized in that: The molar ratio of methanol to phenol is (1.0-3.05):

1.

10. The use of the alkylation catalyst according to claim 7, characterized in that: The mass ratio of the alkylation catalyst to phenol is 2.6%-10.6%.

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