Catalyst for preparing anisole through phenol methanol etherification as well as preparation method and application of catalyst

Abstract

The invention relates to a catalyst for preparing anisole through phenol methanol etherification as well as a preparation method and application of the catalyst. The catalyst takes aluminum phosphate as a carrier and is doped with zirconium oxide; on the basis of the mole number of Al, the mole ratio of P to Al is (0.05-2): 1, and the mole ratio of Zr to Al is (0.08-0.20): 1. Dropwise adding the aluminum-zirconium mixed aqueous solution into the phosphorus source aqueous solution, stirring, standing and washing to obtain a solid sample; and drying and roasting the solid sample to obtain the aluminum phosphate catalyst. Under the action of the catalyst, phenol and methanol are catalyzed to generate anisole. Compared with the prior art, the phenol conversion rate is greater than or equal to 50%, the anisole selectivity is greater than or equal to 85%, highly toxic dimethyl sulfate and a large amount of alkali are not needed, the process is green, the cost is low, separation is simple, and the method is suitable for large-scale industrial production of anisole.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and in particular to a catalyst for the preparation of anisole by etherification of phenol with methanol, its preparation method and application. Background Technology

[0002] Anisole, also known as methyl ether or methoxybenzene, is a colorless liquid with an aromatic odor. It is sparingly soluble in water but readily soluble in organic solvents such as ethanol and ether. This compound has a wide range of industrial applications, commonly used as a solvent, fragrance, and insect repellent. It is also an important intermediate in the synthesis of resins, fragrances, and other organic products.

[0003] Currently, the industrial synthesis of anisole primarily employs liquid-phase reaction methods, typically carried out under alkaline conditions. Common synthetic routes include the reaction of sodium phenoxide with dimethyl sulfate, the reaction of bromobenzene with methanol, and the reaction of sodium phenoxide with chloromethane. However, these traditional methods have significant drawbacks. First, the reactions require a strongly alkaline environment, and the use of excessive alkali not only creates difficulties in subsequent treatment but also generates large amounts of high-salinity wastewater, imposing a severe burden on the environment. Second, some of the raw materials used in these processes (such as dimethyl sulfate and bromobenzene) are highly toxic, posing a threat to the health of production operators and presenting significant safety risks. Furthermore, the use and residues of halogen-containing and sulfur-containing compounds limit the product's application in the high-end fine chemicals sector.

[0004] With increasingly stringent national environmental protection policies, traditional synthesis processes, due to their high pollution, toxicity, and costly waste treatment, are no longer suitable for the current requirements of green chemical industry development. In particular, processes using dimethyl sulfate as a methylating agent are facing increasingly stringent restrictions on industrial application due to poor safety and low environmental compatibility. Therefore, developing a green synthesis process for anisole with low-toxicity raw materials, mild reaction conditions, environmental friendliness, and suitability for large-scale production has become an urgent technical problem to be solved in this field. Gas-phase catalytic reaction, as a promising process route for continuous and clean production, has received widespread attention in recent years, but challenges remain regarding catalyst efficiency, stability, and process cost.

[0005] Patent publication number CN119822930A discloses a method for preparing methyl anisole. In this method, phenol and methanol are catalytically reacted to produce methyl anisole under the action of a composite catalyst. The composite catalyst is a mixture of Ho / β molecular sieve catalyst and Ti / UiO-66 at a mass ratio of Ho / β:Ti / UiO-66 of 0.3-0.6:1. However, this catalyst is used to prepare methyl anisole, not anisole, and its preparation is cumbersome. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology by providing a catalyst, its preparation method, and its application for the etherification of phenol with methanol. This method involves a one-step catalytic reaction of phenol and methanol to produce anisole, resulting in a simple preparation process with high selectivity and low byproduct content. The process uses phenol, which is cheaper, as a raw material, significantly reducing costs compared to cresol. Furthermore, using methanol as a raw material is cheaper than using dimethyl carbonate and dimethyl sulfate in other industrial processes. The continuous fixed-bed process results in high reaction efficiency, eliminates the need for other solvents, and reduces separation costs. Moreover, the reaction steps are simple, achieving synthesis in one step, exhibiting good reactivity and selectivity, and enabling long-term stable operation, making it an ideal process for industrial production.

[0007] The objective of this invention can be achieved through the following technical solutions: One of the technical solutions of the present invention is to provide a catalyst for the etherification of phenol with methanol to prepare anisole, wherein the catalyst uses aluminum phosphate as a support and is doped with zirconium oxide; Based on the number of moles of Al, the molar ratio of P to Al is 0.5~2:1, and the molar ratio of Zr to Al is 0.08~0.20:1.

[0008] Furthermore, based on the number of moles of Al, the molar ratio of P to Al is 0.5~2:1, and the molar ratio of Zr to Al is 0.08~0.15:1.

[0009] The second technical solution of the present invention provides a method for preparing a catalyst for the etherification of phenol with methanol to prepare anisole, comprising the following steps: S1. Dissolve the aluminum source and the zirconium source in water to obtain an aluminum-zirconium mixed aqueous solution; S2. Dissolve the phosphorus source in water to obtain an aqueous solution of the phosphorus source; S3. Add the aluminum-zirconium mixed aqueous solution dropwise to the phosphorus source aqueous solution, stir, let stand, and wash to obtain a solid sample; S4. The solid sample is dried and calcined to obtain aluminum phosphate catalyst, and the catalyst preparation is completed.

[0010] Further, in step S1, the aluminum source is one or more of nitrate nonahydrate, aluminum chloride, or aluminum sulfate; The zirconium source is zirconium nitrate or zirconium oxychloride; The mass ratio of the aluminum source, zirconium source and water is 0.1~0.6:0.001~0.025:1.

[0011] Further, in step S2, the phosphorus source is one or more of ammonium dihydrogen phosphate, triammonium phosphate, or phosphoric acid; The mass ratio of the phosphorus source to water is 0.1 to 0.6:1.

[0012] Further, in step S3, the molar ratio of phosphorus in the phosphorus source aqueous solution and aluminum in the aluminum-zirconium mixed aqueous solution is 0.67~2:1, preferably 0.9~1.1:1.

[0013] Furthermore, in step S3, the dropping speed is 10~50 r / min.

[0014] Further, in step S3, the stirring speed is 550~650 rpm, the stirring time is 0.5~5 h, and the settling time is 0.5~5 h.

[0015] Furthermore, in step S4, the drying temperature is 60~120℃, and the drying time is 5~20h.

[0016] Furthermore, in step S4, the calcination temperature is 400~600℃.

[0017] The third technical solution of the present invention is to provide a catalyst for the preparation of anisole by etherification of phenol with methanol in the gas-phase etherification reaction of phenol and methanol to prepare anisole. Under the action of the catalyst, phenol and methanol are catalyzed to produce anisole.

[0018] Furthermore, the amount of phenol added is 0.4 to 0.8% of the total mass of phenol and methanol.

[0019] Furthermore, the gas-phase etherification reaction is carried out at a temperature of 260-370°C, at atmospheric pressure, and the liquid hourly space velocity (LHSV) of phenol is 1-3 h⁻¹. -1 .

[0020] Furthermore, the gas-phase etherification reaction is carried out in a continuous fixed-bed reaction.

[0021] Compared with the prior art, the present invention has the following advantages: This invention synthesizes aluminum phosphate catalysts via a one-step precipitation method, which has advantages such as simplicity and low cost. Furthermore, when the zirconium-doped catalyst is applied to a fixed-bed gas-phase reaction, the results show that it has high selectivity, reduces the formation of by-products, and effectively improves the yield of anisole.

[0022] This invention provides a one-step catalytic synthesis of anisole from phenol and methanol, exhibiting high selectivity and low byproduct content. The process uses phenol, which is more affordable, as a raw material, significantly reducing costs compared to cresol. Furthermore, methanol is cheaper than other industrially used dimethyl carbonate and dimethyl sulfate. The continuous fixed-bed process ensures high reaction efficiency, eliminates the need for other solvents, and reduces separation costs. Moreover, the simple reaction steps, achieving synthesis in a single step, demonstrate excellent reactivity and selectivity, and allow for long-term stable operation, making it an ideal process for industrial production. Detailed Implementation

[0023] The present invention will now be described in detail with reference to specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments. All other embodiments obtained by those skilled in the art based on the given embodiments without creative effort are within the scope of protection of this application.

[0024] Unless otherwise specified, the reagents, methods, instruments and equipment used in this invention are conventional reagents, methods, instruments and equipment in the art.

[0025] The reactor used in the example: The reaction is carried out in a fixed-bed reactor made of 316L material, the inner diameter of the reaction tube is 20mm, and the catalyst is filled with 316L distillation packing at both ends.

[0026] The composition of the phenol-methanol reaction solution was analyzed by gas chromatography. The operating conditions were as follows: a F60 gas chromatograph with an SE-30, 30m × 0.32mm × 0.5μm column was used; the injection port temperature was 250℃, the column oven temperature was 130℃, and the detector temperature was 280℃. The injection volume was 0.08μL.

[0027] Example 1 A method for preparing a catalyst for the etherification of phenol with methanol to anisole includes the following steps: S1. Dissolve 0.1 mol (37.5 g) aluminum nitrate nonahydrate and 0.01 mol (4.29 g) zirconium nitrate pentahydrate in 300 ml of distilled water to obtain an aluminum-zirconium mixed aqueous solution. The mass ratio of aluminum nitrate nonahydrate, zirconium nitrate pentahydrate and water is 0.125:0.014:1.

[0028] S2. Dissolve 22.33g of triammonium phosphate in 200ml of distilled water to obtain a mixed aqueous solution of phosphorus source. The mass of triammonium phosphate is 0.112 times the mass of distilled water.

[0029] S3. Add the aluminum-zirconium mixed aqueous solution dropwise to the phosphorus source aqueous solution at a rate of 20 r / min.

[0030] S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0031] S5. After drying the solid sample at 110℃ for 12h, it was calcined at 550℃ for 5h in air to obtain the aluminum phosphate catalyst. The molar ratio of P to Al was 1.1:1, and the molar ratio of Zr to Al was 0.1:1.

[0032] Under the action of the catalyst, phenol and methanol are catalytically reacted to produce anisole. The reaction of phenol and methanol is carried out in a continuous fixed-bed reaction. The amount of phenol added is 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol is 370°C, the reaction pressure is 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol is 1.5 h⁻¹. -1 .

[0033] Example 2 The preparation method of a catalyst for the etherification of phenol with methanol to prepare anisole is largely the same as that in Example 1, except that in step S1, the zirconium nitrate pentahydrate is changed from 0.01 mol (4.29 g) to 0.005 mol (2.145 g). The molar ratio of P to Al in the aluminum phosphate catalyst is 1.105:1, and the molar ratio of Zr to Al is 0.05:1.

[0034] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0035] Example 3 A method for preparing a catalyst for the etherification of phenol with methanol to prepare anisole is the same as in Example 1.

[0036] The reaction of phenol with methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370°C, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1 h⁻¹. -1 .

[0037] Comparative Example 1 A method for preparing a catalyst for the etherification of phenol with methanol to anisole includes the following steps: S1. Dissolve 0.1 mol (37.5 g) aluminum nitrate nonahydrate and 0.01 mol (4.29 g) zirconium nitrate pentahydrate in 300 ml of distilled water to obtain an aluminum-zirconium mixed aqueous solution. The mass ratio of aluminum nitrate nonahydrate, zirconium nitrate pentahydrate and water is 0.125:0.014:1.

[0038] S2. Dissolve 44.66g of triammonium phosphate in 200ml of distilled water to obtain a mixed aqueous solution of phosphorus source. The mass of triammonium phosphate is 0.2233 times the mass of distilled water.

[0039] S3. Add the aluminum-zirconium mixed aqueous solution dropwise to the phosphorus source aqueous solution at a rate of 20 r / min.

[0040] S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0041] S5. After drying the solid sample at 110℃ for 12h, it was calcined at 550℃ for 5h in air to obtain the aluminum phosphate catalyst. The molar ratio of P to Al was 2.2:1, and the molar ratio of Zr to Al was 0.1:1.

[0042] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0043] Comparative Example 2 A method for preparing a catalyst for the etherification of phenol with methanol to anisole includes the following steps: S1. Dissolve 0.1 mol (37.5 g) aluminum nitrate nonahydrate and 0.01 mol (4.29 g) zirconium nitrate pentahydrate in 300 ml of distilled water to obtain an aluminum-zirconium mixed aqueous solution. The mass ratio of aluminum nitrate nonahydrate, zirconium nitrate pentahydrate and water is 0.125:0.014:1.

[0044] S2. Dissolve 1.35g of triammonium phosphate in 200ml of distilled water to obtain a mixed aqueous solution of phosphorus source. The mass of triammonium phosphate is 0.007 times the mass of distilled water.

[0045] S3. Add the aluminum-zirconium mixed aqueous solution dropwise to the phosphorus source aqueous solution at a rate of 20 r / min.

[0046] S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0047] S5. After drying the solid sample at 110℃ for 12h, it was calcined at 550℃ for 5h in air to obtain the aluminum phosphate catalyst. The molar ratio of P to Al was 0.07:1, and the molar ratio of Zr to Al was 0.1:1.

[0048] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0049] Comparative Example 3 A method for preparing a catalyst for the etherification of phenol with methanol to anisole includes the following steps: S1. Dissolve 0.1 mol (37.5 g) aluminum nitrate nonahydrate in 200 ml of distilled water to obtain an aluminum source aqueous solution; dissolve 0.01 mol (4.29 g) zirconium nitrate pentahydrate in 200 ml of distilled water to obtain a zirconium source aqueous solution. The mass ratio of aluminum nitrate nonahydrate to water is 0.188:1, and the mass ratio of zirconium nitrate pentahydrate to water is 0.021:1.

[0050] S2. Dissolve 22.33g of triammonium phosphate in 200ml of distilled water to obtain a mixed aqueous solution of phosphorus source. The mass of triammonium phosphate is 0.112 times the mass of distilled water.

[0051] S3. Simultaneously add the aluminum source aqueous solution and the zirconium source aqueous solution to the phosphorus source aqueous solution at a rate of 25 r / min.

[0052] S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0053] S5. After drying the solid sample at 110℃ for 12h, it was calcined at 550℃ for 5h in air to obtain the aluminum phosphate catalyst. The molar ratio of P to Al was 1.1:1, and the molar ratio of Zr to Al was 0.1:1.

[0054] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0055] Comparative Example 4 The preparation method of a catalyst for the etherification of phenol with methanol to prepare anisole is largely the same as that in Example 1, except that in step S3, the aluminum-zirconium mixed aqueous solution is added dropwise to the phosphorus source aqueous solution at a rate of 20 r / min, and the phosphorus source aqueous solution is added dropwise to the aluminum-zirconium mixed aqueous solution at a rate of 20 r / min.

[0056] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0057] Comparative Example 5 A method for preparing a catalyst for the etherification of phenol with methanol to anisole includes the following steps: S1. Dissolve 0.1 mol (37.5 g) of aluminum nitrate nonahydrate in 300 ml of distilled water to obtain an aluminum source aqueous solution, wherein the mass of aluminum nitrate nonahydrate is 0.125 times the mass of distilled water.

[0058] 0.01 mol (4.29 g) of zirconium nitrate pentahydrate was dissolved in 200 ml of distilled water to obtain an aqueous solution of the zirconium source. The mass ratio of zirconium nitrate pentahydrate to water was 0.021:1.

[0059] S2. Dissolve 22.33g of triammonium phosphate in 200ml of distilled water to obtain an aqueous solution of the phosphorus source. The mass of triammonium phosphate is 0.112 times the mass of distilled water.

[0060] S3. Add the aluminum source aqueous solution dropwise to the phosphorus source aqueous solution at a rate of 25 r / min, and then add the zirconium source aqueous solution dropwise to the aluminum-phosphorus mixed aqueous solution at a rate of 25 r / min. S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0061] S5. After drying the solid sample at 110℃ for 12 h, it was calcined at 550℃ for 5 h in air to obtain the aluminum phosphate catalyst. The molar ratio of P to Al in the aluminum phosphate catalyst was 1.1:1, and the molar ratio of Zr to Al was 0.1:1.

[0062] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0063] Comparative Example 6 A method for preparing a catalyst for the etherification of phenol with methanol to anisole includes the following steps: S1. Dissolve 0.1 mol (37.5 g) of aluminum nitrate nonahydrate in 300 ml of distilled water to obtain an aluminum source aqueous solution, wherein the mass of aluminum nitrate nonahydrate is 0.125 times the mass of distilled water.

[0064] 0.01 mol (4.29 g) of zirconium nitrate pentahydrate was dissolved in 200 ml of distilled water to obtain an aqueous solution of the zirconium source. The mass ratio of zirconium nitrate pentahydrate to water was 0.021:1.

[0065] S2. Dissolve 22.33g of triammonium phosphate in 200ml of distilled water to obtain a mixed aqueous solution of phosphorus source. The mass of triammonium phosphate is 0.112 times the mass of distilled water.

[0066] S3. Add the zirconium source aqueous solution dropwise to the phosphorus source aqueous solution at a rate of 25 r / min, and then add the aluminum source aqueous solution dropwise to the zirconium-phosphorus mixed aqueous solution at a rate of 25 r / min. S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0067] S5. After drying the solid sample at 110℃ for 12h, it was calcined at 550℃ for 5h in air to obtain the aluminum phosphate catalyst. The molar ratio of P to Al was 1.1:1, and the molar ratio of Zr to Al was 0.1:1.

[0068] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0069] Comparative Example 7 The preparation method of a catalyst for the etherification of phenol with methanol is largely the same as that in Example 1, except that the calcination temperature in step S5 is changed from 550°C to 380°C.

[0070] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0071] Comparative Example 8 The preparation method of a catalyst for the etherification of phenol with methanol is largely the same as that in Example 1, except that the calcination temperature in step S5 is changed from 550°C to 620°C.

[0072] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0073] Comparative Example 9 The preparation method of a catalyst for the etherification of phenol with methanol to prepare anisole is largely the same as that in Example 1, except that in step S1, the zirconium nitrate pentahydrate is changed from 0.01 mol (4.29 g) to 0.0075 mol (3.22 g). The molar ratio of P to Al in the aluminum phosphate catalyst is 1.1075:1, and the molar ratio of Zr to Al is 0.075:1.

[0074] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0075] Comparative Example 10 The preparation method of a catalyst for the etherification of phenol with methanol to prepare anisole is largely the same as that in Example 1, except that in step S1, the zirconium nitrate pentahydrate is changed from 0.01 mol (4.29 g) to 0.022 mol (9.438 g). The molar ratio of P to Al in the aluminum phosphate catalyst is 1.2:1, and the molar ratio of Zr to Al is 0.22:1.

[0076] The reaction of phenol and methanol was carried out in a continuous fixed-bed reaction. The amount of phenol added was 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol was 370℃, the reaction pressure was 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol was 1.5 h⁻¹. -1 .

[0077] Comparative Example 11 A method for preparing a catalyst for the etherification of phenol with methanol is largely the same as that in Example 1, except that a zirconium source is not added. The method includes the following steps: S1. Dissolve 0.1 mol (37.5 g) of aluminum nitrate nonahydrate in 300 ml of distilled water to obtain an aluminum source aqueous solution. The mass ratio of aluminum nitrate nonahydrate to water is 0.125:1.

[0078] S2. Dissolve 22.33g of triammonium phosphate in 200ml of distilled water to obtain a mixed aqueous solution of phosphorus source. The mass of triammonium phosphate is 0.112 times the mass of distilled water.

[0079] S3. Add the aluminum source aqueous solution to the phosphorus source aqueous solution at a rate of 20 r / min.

[0080] S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0081] S5. After drying the solid sample at 110℃ for 12h, it was calcined at 550℃ for 5h in air to obtain the aluminum phosphate catalyst. The molar ratio of P to Al was 1.1:1, and the amount of Zr added was 0.

[0082] Under the action of the catalyst, phenol and methanol are catalytically reacted to produce anisole. The reaction of phenol and methanol is carried out in a continuous fixed-bed reaction. The amount of phenol added is 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol is 370°C, the reaction pressure is 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol is 1.5 h⁻¹. -1 .

[0083] Comparative Example 12 A method for preparing a catalyst for the etherification of phenol with methanol is largely the same as that in Example 1, except that an aluminum source is not added. The method includes the following steps: S1. 0.01 mol (4.29 g) of zirconium nitrate pentahydrate was dissolved in 300 ml of distilled water to obtain an aqueous solution of the zirconium source. The mass ratio of zirconium nitrate pentahydrate to water was 0.125:0.014:1.

[0084] S2. Dissolve 22.33g of triammonium phosphate in 200ml of distilled water to obtain a mixed aqueous solution of phosphorus source. The mass of triammonium phosphate is 0.112 times the mass of distilled water.

[0085] S3. Add the zirconium source aqueous solution dropwise to the phosphorus source aqueous solution at a rate of 20 r / min.

[0086] S4. Stir at 500 r / min for 1 h, let stand for aging for 1 h, wash with distilled water until the conductivity is 500~1500, and obtain a solid sample.

[0087] S5. After drying the solid sample at 110℃ for 12h, it was calcined at 550℃ for 5h in air to obtain the aluminum phosphate catalyst. The molar ratio of Zr to P was 0.1:1, and the amount of Al added was 0.

[0088] Under the action of the catalyst, phenol and methanol are catalytically reacted to produce anisole. The reaction of phenol and methanol is carried out in a continuous fixed-bed reaction. The amount of phenol added is 0.59% of the total mass of phenol and methanol. The reaction temperature of phenol and methanol is 370°C, the reaction pressure is 1 bar (A), and the liquid hourly space velocity (LHSV) of phenol is 1.5 h⁻¹. -1 .

[0089] The composition of the phenol-methanol reaction solution was analyzed by gas chromatography. The operating conditions were as follows: a F60 gas chromatograph with an SE-30, 30m × 0.32mm × 0.5μm column was used; the injection port temperature was 250℃, the column oven temperature was 130℃, and the detector temperature was 280℃. The injection volume was 0.08μL. The specific results are shown in Table 1.

[0090] Table 1. Phenol conversion and anisole selectivity results for Example 1 and Comparative Example 1 The experiments in Examples 1-3 confirmed that the Zr-doped aluminum phosphate catalyst has excellent catalytic performance. The catalyst exhibits the best catalytic performance only when the molar mass of P is close to the sum of the molar masses of Al and Zr. The catalytic performance is optimal when the molar mass of Zr is 0.005 or 0.01, with high phenol conversion and anisole selectivity.

[0091] The results from Examples 1 and 1-2 indicate that excessive or insufficient phosphorus source leads to a drastic decrease in conversion rate or even no reaction. Insufficient phosphorus source results in incomplete precipitation of aluminum-zirconium. Comparative Examples 3-6 show that different addition sequences alter the catalytic performance of the catalyst. Only when the aluminum-zirconium mixed aqueous solution is added dropwise to the phosphorus source aqueous solution does the catalyst exhibit excellent activity. Different addition sequences alter crystal growth due to significant differences in acid-base environments. Comparative Examples 7-8 demonstrate that calcination temperature also affects catalyst activity; different calcination temperatures influence the catalyst structure. At 550°C, the catalyst exhibits excellent activity. Comparative Examples 9 and 10 show that excessively high zirconium doping results in higher catalyst conversion due to its higher acidity, but also significantly reduced selectivity. Therefore, only an appropriate amount of zirconium enhances catalyst activity. Comparative experiments 11 and 12 confirmed that the pure AlP catalyst has high selectivity, while the activity drops sharply to 36.8% without zirconium. The pure ZrP catalyst has high conversion rate. Appropriate doping of Al and Zr can effectively ensure high selectivity while improving the conversion rate of the catalyst, proving that zirconium is the key to controlling acid strength and achieving both high activity and high selectivity.

[0092] Although the present invention has been described in detail above with general descriptions, specific embodiments, and experiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A catalyst for the etherification of phenol with methanol to prepare anisole, characterized in that, The catalyst uses aluminum phosphate as a support and is doped with zirconium oxide; Based on the number of moles of Al, the molar ratio of P to Al is 0.5~2:1, and the molar ratio of Zr to Al is 0.05~0.20:

1.

2. The method for preparing a catalyst for the etherification of phenol with methanol to anisole as described in claim 1, characterized in that, Includes the following steps: S1. Dissolve the aluminum source and the zirconium source in water to obtain an aluminum-zirconium mixed aqueous solution; S2. Dissolve the phosphorus source in water to obtain an aqueous solution of the phosphorus source; S3. Add the aluminum-zirconium mixed aqueous solution dropwise to the phosphorus source aqueous solution, stir, let stand, and wash to obtain a solid sample; S4. The solid sample is dried and calcined to obtain aluminum phosphate catalyst, and the catalyst preparation is completed.

3. The method for preparing a catalyst for the etherification of phenol with methanol to anisole according to claim 2, characterized in that, In step S1, the aluminum source is one or more of nitrate nonahydrate, aluminum chloride, or aluminum sulfate; The zirconium source is zirconium nitrate or zirconium oxychloride; The mass ratio of the aluminum source, zirconium source and water is 0.1~0.6:0.001~0.025:

1.

4. The method for preparing a catalyst for the etherification of phenol with methanol to anisole according to claim 2, characterized in that, In step S2, the phosphorus source is one or more of ammonium dihydrogen phosphate, triammonium phosphate, or phosphoric acid; The mass ratio of the phosphorus source to water is 0.1 to 0.6:

1.

5. The method for preparing a catalyst for the etherification of phenol with methanol to anisole according to claim 2, characterized in that, In step S3, the molar ratio of phosphorus in the phosphorus source aqueous solution and aluminum in the aluminum-zirconium mixed aqueous solution is 0.67~2:

1.

6. The method for preparing a catalyst for the etherification of phenol with methanol to anisole according to claim 2, characterized in that, In step S4, the calcination temperature is 400~600℃.

7. The application of the catalyst for the etherification of phenol with methanol as described in claim 1 in the gas-phase etherification reaction of phenol and methanol to prepare anisole, characterized in that, Under the action of the catalyst, phenol and methanol are catalytically converted into anisole.

8. The application of the catalyst for the etherification of phenol with methanol to prepare anisole according to claim 7, characterized in that, The amount of phenol added is 0.4 to 0.8% of the total mass of phenol and methanol.

9. The application of the catalyst for the etherification of phenol with methanol to prepare anisole according to claim 7, characterized in that, The gas-phase etherification reaction is carried out at a temperature of 260-370°C and a pressure of atmospheric pressure, with a liquid hourly space velocity (LHSV) of phenol of 1-3 h⁻¹. -1 .

10. The application of the catalyst for the etherification of phenol with methanol to prepare anisole according to claim 7, characterized in that, The gas-phase etherification reaction is carried out in a continuous fixed-bed reaction.

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