Preparation method for synthesizing p-xylene catalyst

Abstract

The invention belongs to the technical field of chemical catalysis, and discloses a preparation method of a catalyst for synthesizing p-xylene, a nano H-Beta molecular sieve synthesized by the invention is used as a catalyst, and the nano H-Beta molecular sieve is used in a method for synthesizing p-xylene (PX) by catalyzing 2, 5-dimethylfuran (2, 5-DMF) and acrylic acid (AA). The nano H-Beta molecular sieve synthesized by the method is relatively small in particle size, the resistance of mass transfer diffusion in the molecular sieve is remarkably reduced, and the utilization rate of active sites in the Beta molecular sieve is improved, so that the molecular sieve catalyst has the advantages of relatively high catalytic activity and selectivity and environmental friendliness.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical catalysis, and specifically relates to a method for synthesizing p-xylene (PX) by catalyzing 2,5-dimethylfuran (DMF) and acrylic acid (AA) using Beta molecular sieve as a catalyst and an application thereof. Background Art

[0002] PX is an important organic raw material and the basic raw material of the aromatics industry chain. About 97% of PX is used to produce purified terephthalic acid, and the remaining 3% is mainly used to prepare dimethyl terephthalate. Terephthalic acid can be further reacted with ethylene glycol to produce polyethylene terephthalate (PET), which can be used to produce polyester fibers and polyester plastics, and is widely used in textiles, packaging and other fields.

[0003] At present, PX is mainly produced by converting petroleum aromatics. With the deepening of the energy revolution, new routes for preparing PX using biomass as raw materials have become a research hotspot. DMF containing a conjugated diene structure can be reacted with a series of dienophiles to prepare PX through Diels-Alder and dehydration reactions. Ethylene is a commonly used dienophile, but the reaction conditions require high temperature and high pressure, which greatly limits the further industrialization of the reaction. Using biomass-based acrylic acid as a dienophile, this method has mild conditions, simple operation, obvious advantages, and shows strong prospects for industrial application.

[0004] Molecular sieves are a type of crystalline aluminosilicate materials with uniform pore structures. Their active centers, pore structures, crystal morphologies, and topological structures are diverse and adjustable, and have received extensive attention from researchers in the field of heterogeneous catalysis. Many achievements have been made in the preparation of PX from DMF using molecular sieves as catalysts. Commonly used molecular sieves include Y-type, ZSM-5, and Beta molecular sieves. However, due to the microporous structure of molecular sieves, there are serious diffusion limitations, resulting in low utilization of their active sites. In previous studies, we prepared MWW molecular sieves with high external specific surface area for catalytic synthesis of PX from 2,5-DMF and AA. The outer surface of the MWW molecular sieve provides a large number of easily accessible active sites, which significantly improves the activity of the catalyst (CN117069558A). However, due to the smaller ten-membered ring pores of MWW, its internal active sites have not been fully utilized.

[0005] Compared with MWW molecular sieve, Beta molecular sieve has a three-dimensional twelve-membered ring pore structure. The relatively large molecular sieve pores can provide diffusion for reactants and products, and the large specific surface area can also promote the contact between reactant molecules and the active centers on the molecular sieve surface. However, the traditional Beta molecular sieve has a long internal diffusion path and still has strong diffusion limitations, which makes it difficult to improve the catalytic activity. Therefore, it is urgent to develop a molecular sieve catalyst with high catalytic activity for use in the reaction of 2,5-DMF to synthesize PX. Summary of the invention

[0006] The present invention aims at the problems of mass transfer influence of molecular sieve catalyst, low activity and environmental unfriendliness in the existing reaction of synthesizing PX from 2,5-dimethylfuran, and provides a nano-type H-Beta molecular sieve as a catalyst. The molecular sieve catalyst exhibits high catalytic activity and selectivity as well as environmentally friendly advantages.

[0007] To solve the above technical problems, the present invention is specifically carried out according to the following steps:

[0008] A preparation method for a catalyst for synthesizing p-xylene, using a nano-type H-Beta molecular sieve as a catalyst, reactants being 2,5-dimethylfuran and acrylic acid, wherein the molar ratio of 2,5-dimethylfuran to acrylic acid is 1:2; the reaction is carried out in a magnetic stirring kettle, the reaction temperature is 160°C to 190°C, nitrogen is used as a protective gas, and under normal pressure conditions.

[0009] The reaction time is 3-15h: the relative amounts of the catalyst and 2,5-dimethylfuran are: 0.1g:0.015mol; the reaction solvent is n-heptane.

[0010] As a limitation of the present invention, the preparation method of the nano-type H-Beta molecular sieve catalyst of the present invention is:

[0011] (1) Dissolve NaOH in deionized water at room temperature, add NaAlO2, and stir for 1 h to obtain a clear and transparent solution;

[0012] (2) then slowly adding tetraethylammonium hydroxide (TEAOH, 25 wt% aqueous solution) to the solution obtained in step (1), and continuing stirring for 0.5 h after the addition is complete;

[0013] (3) Weigh hydrophilic silica, add it to the solution obtained in step (2) in small amounts several times, and stir in a water bath at 30°C for 6 hours to obtain a transparent colloidal precursor, the molar ratio of the precursor is: SiO2: 0.025Al2O3: 0.025-0.05Na2O: 12-16H2O: 0.3TEAOH; more preferably, the molar ratio of Na2O to SiO2 is 0.05:1.

[0014] (4) The precursor is transferred to a hydrothermal reactor and placed in an oven at 150° C. for crystallization for 3 days. The precursor in the hydrothermal reactor is centrifuged, washed, and dried to obtain a white powder, namely, the Beta molecular sieve without the template.

[0015] (5) placing the white powder obtained in step (4) in a muffle furnace, heating to 550° C. and calcining for 6 h to obtain a Na-type Beta molecular sieve;

[0016] (6) Na-type Beta molecular sieve was filtered through 1 mol·L -1 The NH4Cl solution was ion exchanged three times at 80°C, and after drying, it was placed in a muffle furnace, heated to 550°C, and calcined for 4 hours to obtain H-type Beta molecular sieve.

[0017] After adopting the above technical solution, the beneficial effects achieved by the present invention are:

[0018] The present invention provides a simple preparation method for a catalyst for synthesizing p-xylene. The nano-type H-Beta molecular sieve obtained by the technical solution of the present invention has a small particle size, significantly reduces the resistance of mass transfer and diffusion inside the molecular sieve, improves the utilization rate of the active sites inside the Beta molecular sieve, and makes the catalyst exhibit high catalytic activity. Under the conditions of a reaction temperature of 190°C, a reaction time of 15h, a catalyst dosage of 0.1g, and an initial reaction pressure of normal pressure, a 2,5-DMF conversion rate of 99% and a PX selectivity of 98% can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 3 is the XRD diagram of Example 4, from which it can be seen that the prepared H-Beta has a BEA topological structure with good crystallinity.

[0020] Figure 2 This is a transmission electron microscope image of Example 4. It can be seen from the image that the prepared H-Beta is a nanomolecular sieve with regular morphology and uniform size. DETAILED DESCRIPTION

[0021] The present invention will be further described with reference to the following examples, but it should be understood that these examples are only for illustration and should not be construed as limitations of the present invention.

[0022] In the present invention, a nano-type H-Beta molecular sieve is prepared by a hydrothermal synthesis method. By adjusting the amount of raw materials added during the synthesis process, nano-type H-Beta molecular sieves of different particle sizes can be obtained. The specific embodiments are as follows:

[0023] Example 1

[0024] First, 3.105g NaAlO2 was dissolved in 23.733g deionized water, and then added to 88.356g tetraethylammonium hydroxide (TEAOH, 25wt% aqueous solution) solution, stirred for 30min, and then 30g hydrophilic silica was slowly added, and stirred for 6h in a water bath at 30℃ to obtain a transparent colloidal precursor. The molar ratio of the transparent colloidal precursor was controlled to be: SiO2: 0.025Al2O3: 0.025Na2O: 12H2O: 0.3TEAOH; finally, the transparent colloidal precursor was transferred to the lining of a crystallization reactor with a polytetrafluoroethylene lining, and crystallized in an oven at 150℃ for 2 days. The precursor in the hydrothermal reactor was centrifuged, washed, and dried to obtain a white powder without template removal. The obtained white powder was calcined at 550℃ in a muffle furnace for 6h to obtain a series of Na-type Beta molecular sieves. Then, 1.0mol·L -1 The NH4Cl aqueous solution was ion exchanged three times at 80°C, then dried and calcined in a muffle furnace at 550°C for 4h to obtain H-Beta-0.025.

[0025] Example 2

[0026] First, 0.2g NaOH and 3.105g NaAlO2 were dissolved in 23.733g deionized water, and then added to 88.356g tetraethylammonium hydroxide (TEAOH, 25wt% aqueous solution) solution, stirred for 30min, and then 30g hydrophilic silica was slowly added, and stirred for 6h in a water bath at 30℃ to obtain a transparent colloidal precursor. The molar ratio of the transparent colloidal precursor was controlled to be: SiO2: 0.025Al2O3: 0.03Na2O: 12H2O: 0.3TEAOH; finally, the transparent colloidal precursor was transferred to the lining of a crystallization reactor with a polytetrafluoroethylene lining, and crystallized in an oven at 150℃ for 2 days. The precursor in the hydrothermal reactor was centrifuged, washed, and dried to obtain a white powder without template removal. The obtained white powder was calcined at 550℃ in a muffle furnace for 6h to obtain a series of Na-type Beta molecular sieves. Then, 1.0mol·L -1 The product was ion exchanged with NH4Cl aqueous solution three times, then dried and calcined in a muffle furnace at 550°C for 4 h to obtain H-Beta-0.03.

[0027] Example 3

[0028] First, 0.6g NaOH and 3.105g NaAlO2 were dissolved in 23.733g deionized water, and then added to 88.356g tetraethylammonium hydroxide (TEAOH, 25wt% aqueous solution) solution, stirred for 30min, and then 30g hydrophilic silica was slowly added, and stirred for 6h in a water bath at 30℃ to obtain a transparent colloidal precursor. The molar ratio of the transparent colloidal precursor was controlled to be: SiO2: 0.025Al2O3: 0.04Na2O: 12H2O: 0.3TEAOH; finally, the transparent colloidal precursor was transferred to the lining of a crystallization reactor with a polytetrafluoroethylene lining, and crystallized in an oven at 150℃ for 2 days. The precursor in the hydrothermal reactor was centrifuged, washed, and dried to obtain a white powder without template removal. The obtained white powder was calcined at 550℃ in a muffle furnace for 6h to obtain a series of Na-type Beta molecular sieves. Then, 1.0mol·L -1 The product was ion exchanged with NH4Cl aqueous solution three times, then dried and calcined in a muffle furnace at 550°C for 4 h to obtain H-Beta-0.04.

[0029] Example 4

[0030] First, 1g NaOH and 3.105g NaAlO2 were dissolved in 23.733g deionized water, and then added to 88.356g tetraethylammonium hydroxide (TEAOH, 25wt% aqueous solution) solution, stirred for 30min, and then 30g hydrophilic silica was slowly added, and stirred for 6h in a water bath at 30℃ to obtain a transparent colloidal precursor. The molar ratio of the transparent colloidal precursor was controlled to be: SiO2: 0.025Al2O3: 0.05Na2O: 12H2O: 0.3TEAOH; finally, the transparent colloidal precursor was transferred to the lining of a crystallization reactor with a polytetrafluoroethylene lining, and crystallized in an oven at 150℃ for 2 days. The precursor in the hydrothermal reactor was centrifuged, washed, and dried to obtain a white powder without template removal. The obtained white powder was calcined at 550℃ in a muffle furnace for 6h to obtain a series of Na-type Beta molecular sieves. Then, 1.0mol·L -1 The product was ion exchanged with NH4Cl aqueous solution three times, then dried and calcined in a muffle furnace at 550°C for 4 h to obtain H-Beta-0.05.

[0031] The catalyst obtained in Examples 1 to 4 above was applied to the reaction of synthesizing PX from 2,5-DMF and AA, and the specific application was as follows:

[0032] Example 5

[0033] 2,5-Dimethylfuran (2,5-DMF) and acrylic acid (AA) were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1, AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.025 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 3h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0034] Example 6

[0035] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.03 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 3h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0036] Example 7

[0037] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.04 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 3h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0038] Example 8

[0039] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1, the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.05 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 3h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0040] Example 9

[0041] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.05 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 5h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0042] Example 10

[0043] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.05 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 10h; after the reaction, the reactor is placed in an ice water bath for cooling. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0044] Embodiment 11

[0045] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.05 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0046] Example 12

[0047] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.05 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 170℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0048] Embodiment 13

[0049] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.05 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 180℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0050] Embodiment 14

[0051] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-0.05 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 190℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath for cooling. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0052] Comparative Example 1

[0053] The preparation method of H-Beta-Com is as follows:

[0054] First, 1.5 g of commercial H-Beta molecular sieve powder with a silicon-aluminum ratio of 20 and no template removal (Tianjin Nanhua Catalyst Co., Ltd.) was evenly spread in a porcelain boat, and then placed in a muffle furnace and calcined at 600°C for 4 hours to remove the organic template in the molecular sieve to obtain H-Beta-Com.

[0055] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-Com is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 160℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath for cooling. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0056] Comparative Example 2

[0057] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-Com is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 170℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0058] Comparative Example 3

[0059] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-Com is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 180℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath for cooling. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0060] Comparative Example 4

[0061] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of H-Beta-Com is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 190℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0062] Comparative Example 5

[0063] As a comparative example, the 0.25H-MCM-22 molecular sieve of Example 10 in CN 117069558 A was used as a catalyst.

[0064] 2,5-DMF and AA were mixed in a molar ratio of 1:2, and the concentration of 2,5-DMF was 0.5 mol·L -1 , AA concentration is 1.0 mol·L -1 , the solvent is n-heptane, the total reaction liquid volume is 30mL, the mixed solution is transferred to a magnetic stirring kettle, 0.1g of 0.25H-MCM-22 is added, and the gas in the kettle is replaced three times with high-purity nitrogen. The reaction temperature is 190℃, the initial pressure is normal pressure, and the reaction time is 15h; after the reaction is completed, the reactor is placed in an ice water bath to cool. The main products are PX and by-products 2,5-hexanedione and 2,5-dimethylbenzoic acid.

[0065] The specific surface areas and catalytic activities of the catalysts obtained in Examples 1 to 4 and the catalysts used in Comparative Examples 1 to 3 are compared, as shown in Table 1 below:

[0066] Table 1 Comparison of catalytic activity of the catalyst obtained in the embodiment and the comparative example

[0067]

[0068]

[0069] It can be seen from Table 1 that the H-Beta-0.05 sample synthesized when the ratio of Na2O to SiO2 is 0.05 has the best catalytic activity. Compared with Comparative Example 4, under the same reaction conditions, the 2,5-DMF conversion rate and PX selectivity of H-Beta-0.05 are 61% and 35% higher than those of H-Beta-Com, respectively, and the former has a significant advantage. Compared with Comparative Example 5, under the same reaction conditions, the 2,5-DMF conversion rate and PX selectivity of H-Beta-0.05 are higher than those of 0.25H-MCM-22, which has a significant advantage.

[0070] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a catalyst for synthesizing p-xylene, characterized in that: Under gas protection, nano-type H-Beta molecular sieve is used as a catalyst to catalyze the reaction of 2,5-dimethylfuran and acrylic acid to obtain p-xylene; the molar ratio of the nano-type Beta molecular sieve precursor components is: SiO2: 0.025Al2O3: 0.025-0.05Na2O: 12-16H2O: 0.3TEAOH; the Beta molecular sieve is ion exchanged in NH4Cl solution to obtain H-type Beta molecular sieve.

2. The method for preparing a catalyst for synthesizing p-xylene according to claim 1, characterized in that: The reaction temperature is 160°C to 190°C, and the reaction time is 3-15h.

3. The method for preparing a catalyst for synthesizing p-xylene according to claim 1, characterized in that: Nitrogen was used as the protective gas.

4. The method for preparing the catalyst for synthesizing p-xylene according to claim 1, characterized in that: The molar ratio of 2,5-dimethylfuran to acrylic acid is 1:

2.

5. The method for preparing the catalyst for synthesizing p-xylene according to claim 1, characterized in that: The molar ratio of Na2O to SiO2 is 0.05:

1.

6. The method for preparing the catalyst for synthesizing p-xylene according to claim 1, characterized in that: The reaction pressure is normal pressure.

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