Catalyst for synthesizing 2-tert-butyl p-cresol as well as preparation method and application of catalyst

Abstract

The invention discloses a catalyst for synthesizing 2-tert-butyl p-cresol as well as a preparation method and application of the catalyst, and belongs to the technical field of chemical catalysts. The invention discloses a catalyst for synthesizing 2-tert-butyl p-cresol. The catalyst is metal oxide loaded phosphotungstic acid; the metal oxide is one of SiO2, TiO2 and ZrO2, or is a metal composite oxide of ZrO2 and TiO2. The catalyst is a solid acid catalyst with excellent performance, is easy to separate from a product, has mild reaction conditions (normal pressure, low temperature and short reaction time) and high catalytic activity, and is suitable for industrial production. The technical problem that industrial production cannot be achieved due to the fact that an existing heterogeneous catalyst for synthesizing 2-tert-butyl p-cresol is high in preparation cost, prone to pollution and poor in catalytic activity can be solved.

Description

Technical Field

[0001] This invention belongs to the field of chemical catalyst technology, specifically relating to a catalyst for synthesizing 2-tert-butyl-p-cresol, its preparation method, and its application. Background Technology

[0002] 2-tert-butyl-p-cresol is an organic intermediate that plays an important role in the field of organic synthesis. It is widely used in the production of surfactants, antioxidants, and ultraviolet absorbers. For example, it is used in the synthesis of ultraviolet absorber UV-326. This product is one of the earliest and most widely used light stabilizers. It has low toxicity, is resistant to acids and alkalis, has antioxidant properties, and strong ultraviolet absorption capabilities, so it is widely used in industries such as polyester, polyolefins, and polyvinyl chloride.

[0003] There are basically two process routes for the production of 2-tert-butyl-p-cresol: the p-cresol alkylation method and the disproportionation alkylation method of p-cresol and 2,6-di-tert-butyl-p-cresol. Currently, most companies use the p-cresol alkylation method. The alkylating agent used in the p-cresol alkylation method can be isobutylene or tert-butanol. Commonly used catalysts include concentrated sulfuric acid, phosphoric acid, or organic sulfonic acids, as well as ion exchange resins. As is well known, the use of liquid acid catalysts leads to many drawbacks, such as complex processes, numerous byproducts, difficult product separation, easy corrosion of equipment, severe environmental pollution, and the inability to recycle the catalyst. Although the ion exchange resin method is non-corrosive to equipment and environmentally friendly, ion exchange resins are unstable at high temperatures, and their catalytic activity and selectivity are not good enough. In addition, they are relatively expensive, and sometimes poisoned catalysts cannot be regenerated, so they are not ideal catalysts either. Summary of the Invention

[0004] The purpose of this invention is to provide a catalyst for the synthesis of 2-tert-butyl-p-cresol, its preparation method, and its application, in order to solve the technical problems of existing heterogeneous catalysts for the synthesis of 2-tert-butyl-p-cresol, which have high preparation costs, are prone to pollution, and have poor catalytic activity, thus preventing industrial production.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention discloses a catalyst for synthesizing 2-tert-butyl-p-cresol, wherein the catalyst for synthesizing 2-tert-butyl-p-cresol is phosphotungstic acid supported on a metal oxide. The metal oxide is one of SiO2, TiO2 and ZrO2, or a composite oxide of ZrO2 and TiO2.

[0006] Furthermore, the mass of the phosphotungstic acid is 3% to 15% of the mass of the metal oxide.

[0007] This invention also discloses a method for preparing the above-mentioned catalyst for synthesizing 2-tert-butyl-p-cresol, comprising the following steps: A mixed solution is obtained by mixing metal oxide, phosphotungstic acid, and water. The mixed solution was subjected to ultrasonication, impregnation, filtration and drying in sequence to obtain a solid product; The solid product was calcined to obtain a catalyst for the synthesis of 2-tert-butyl-p-cresol.

[0008] Furthermore, the mass ratio of metal oxide to water in the mixed solution is 5% to 20%.

[0009] Furthermore, the mass of the added phosphotungstic acid is 3% to 15% of the mass of the metal oxide.

[0010] Furthermore, the ultrasonic treatment time is 3-10 hours, the immersion time is 4-10 hours, the drying temperature is 70-100°C, and the drying time is 5-10 hours. The calcination process is carried out at a temperature of 300-500℃ for 3-8 hours.

[0011] Furthermore, the preparation method of the ZrO2 and TiO2 metal composite oxide is as follows: S1: Add n-butyl titanate and zirconium n-butoxide to n-butanol, and stir to obtain a mixed solution; S2: Then add ammonia solution dropwise to the mixed solution to adjust the pH value, and continue stirring; S3: After filtering and washing the stirred solution, a solid is obtained; the solid is then dried, ground, and calcined to obtain a metal composite oxide of ZrO2 and TiO2, denoted as T. x Z y O; where X is 2~8 and Y is 2~8.

[0012] Further, in S1, the concentrations of both n-butyl titanate and zirconium n-butoxide in the mixed solution are 0.01~0.1 mol / L; the stirring time is 2-10 h; in S2, the mass concentration of the ammonia water is 5%~10%; the pH value is adjusted to 10~11; the stirring time is 4-10 h. In step S3, the drying temperature is 70-100℃ and the time is 2-8 hours; the calcination temperature is 600-800℃ and the time is 2-10 hours.

[0013] This invention also discloses the application of the above-mentioned catalyst in the synthesis of 2-tert-butyl-p-cresol, comprising the following steps: After mixing p-cresol and tert-butanol, the catalyst was added to carry out the reaction. After the reaction was completed, 2-tert-butyl-p-cresol was obtained.

[0014] Further, the molar ratio of p-cresol to tert-butanol is 1:(1.1-3); the mass of the catalyst added is 0.2~20 wt.% of the mass of p-cresol. The reaction is carried out at a temperature of 90~120℃ for a time of 0.5~6h.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a catalyst for the synthesis of 2-tert-butyl-p-cresol, which is constructed by supporting phosphotungstic acid on a metal oxide support; pure phosphotungstic acid typically has a small specific surface area (generally less than 10 m²). 2 / g), resulting in a large number of acid sites being embedded inside the bulk phase, leading to low catalytic reaction efficiency; while metal oxide supports have a high specific surface area and abundant pore structure, enabling phosphotungstic acid to be highly dispersed on their surface, forming a monolayer or sub-monolayer cover, thereby significantly increasing the exposure of active sites and improving catalytic activity; SiO2, TiO2, ZrO2 or T x Z y A strong interaction can be formed between the O support and phosphotungstic acid, resulting in a W–O–M bond (where M is a metal). This interaction helps anchor phosphotungstic acid molecules, effectively inhibiting their aggregation, migration, or decomposition during heating, thereby improving the catalyst's thermal stability and broadening its applicable temperature range. Simultaneously, this interaction can introduce new Lewis acid sites, achieving synergistic catalysis between Brønsted and Lewis acids, forming new active centers. The resulting catalyst is a high-performance solid acid catalyst that is easily separated from the product, operates under mild reaction conditions (atmospheric pressure, low temperature, and short reaction time), and exhibits high catalytic activity. It can solve the technical problems of existing heterogeneous catalysts for the synthesis of 2-tert-butyl-p-cresol, such as high preparation cost, easy contamination, and poor catalytic activity, which prevent industrial-scale production.

[0016] The present invention also discloses a method for preparing the above-mentioned catalyst. The preparation only requires a simple impregnation method combined with calcination treatment to obtain the target catalyst. The whole process is simple and easy to operate and can be industrialized.

[0017] The present invention also discloses a method for preparing the above-mentioned ZrO2-TiO2 composite oxide. As a solid acid catalyst, the ZrO2-TiO2 composite oxide has the core advantage of creating a stronger and more stable acidic site than a single component through the strong synergistic effect between the components, and has comprehensive advantages such as higher activity, stable structure and tunable properties.

[0018] This invention also discloses the application of the above-mentioned catalyst in the synthesis of 2-tert-butyl-p-cresol. Using the catalyst of this invention is environmentally friendly and pollution-free. The solid catalyst can be recycled and reused, is easy to separate from the product, and the reaction conditions are mild (atmospheric pressure, low temperature, short reaction time). It has high catalytic activity and good prospects for industrial application.

[0019] According to relevant experimental results, after using the metal oxides (SiO2, TiO2, ZrO2 or ZrO2) of the present invention, x T y After using the phosphotungstic acid catalyst supported by O), the conversion rate of p-cresol in the reaction of p-cresol and tert-butanol to synthesize 2-tert-butyl-p-cresol is not less than 85%, and the yield of 2-tert-butyl-p-cresol is not less than 75%; using the composite metal oxide (T) of the present invention x Z y With the addition of phosphotungstic acid catalyst supported on O), the conversion rate of p-cresol in the reaction of p-cresol and tert-butanol to synthesize 2-tert-butyl-p-cresol is not less than 90%, and the yield of 2-tert-butyl-p-cresol is not less than 80%. Detailed Implementation

[0020] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0022] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0023] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0024] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0025] To address the problems of homogeneous catalysts used in the preparation of 2-tert-butyl-p-cresol from p-cresol and tert-butanol, such as easy corrosion of equipment, severe environmental pollution, inability to recycle the catalyst, difficulty in product separation, complex processes, and numerous byproducts, as well as the low activity and easy deactivation of heterogeneous catalysts, this invention provides a novel solid catalyst. This catalyst is low in cost, easy to prepare, environmentally friendly, recyclable, easily separated from the product, operates under mild reaction conditions (atmospheric pressure, low temperature, and short reaction time), exhibits high catalytic activity, and shows promising prospects for industrial application.

[0026] This invention provides a catalyst for the synthesis of 2-tert-butyl-p-cresol, wherein the catalyst is phosphotungstic acid supported on a metal oxide. The metal oxide is SiO2, TiO2, ZrO2, or a composite oxide of ZrO2 and TiO2 (hereinafter referred to as "T"). x Z y One of the ones in "O").

[0027] The catalyst contains the following components by mass percentage: phosphotungstic acid accounts for 3% to 15% of the mass of the metal oxide.

[0028] This invention also discloses a co-precipitation method for preparing composite oxides ZrO2 and TiO2. x T y Method O includes the following steps: Equal molar amounts of n-butyl titanate and zirconium n-butoxide were added to n-butanol and stirred continuously for 2-10 hours until the concentrations of n-butyl titanate and zirconium n-butoxide were both 0.01-0.1 mol / L. Then, 5%-10% ammonia solution was added dropwise using a peristaltic pump. After adjusting the pH of the solution to 10-11, the addition was stopped, and stirring continued for 4-10 hours. The solution was then filtered and washed several times with distilled water to obtain a white solid (Ti(OH)4-Zr(OH)4). The obtained white solid was dried in an oven at 70-100℃ for 2-8 hours, followed by grinding. The ground white solid was placed in a crucible and calcined in a muffle furnace at 600-800℃ for 2-10 hours to obtain T5Z5O with a molar ratio of 5:5. Bimetallic oxide supports T5Z5O with different molar ratios (8:2, 6:4, 4:6, 2:8) were also prepared. x Z y O is prepared by the method described above.

[0029] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0030] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0031] Example 1 Weigh 5g of metal oxide SiO2 and 0.25g of phosphotungstic acid (HPA) into a beaker, then add 25g of distilled water, sonicate for 3 hours, soak for 8 hours, filter, dry in an oven at 100℃ for 8 hours, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 400℃ for 3 hours to obtain a catalyst with an HPA loading of 5% (mass fraction), denoted as 5%HPA / SiO2.

[0032] Cresol and tert-butanol were mixed in a molar ratio of 1:1.2. The mass percentage of 5% HPA / SiO2 catalyst added was 1% of the mass of p-cresol. The reaction temperature was 90℃, the reaction pressure was atmospheric pressure, and the reaction time was 4h to obtain 2-tert-butyl-p-cresol. The p-cresol conversion rate was 86%, and the 2-tert-butyl-p-cresol yield was 78%.

[0033] Example 2 Weigh 5g of metal oxide SiO2 and 0.5g of phosphotungstic acid (HPA) into a beaker, then add 50g of distilled water, sonicate for 5h, soak for 8h, filter, dry in an oven at 90℃ for 10h, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 300℃ for 5h to obtain a catalyst with an HPA loading of 10% (mass fraction), denoted as 10%HPA / SiO2.

[0034] Cresol and tert-butanol were mixed in a molar ratio of 1:1.5. The mass percentage of 10% HPA / SiO2 catalyst added was 0.8% of the mass of p-cresol. The reaction temperature was 110℃, the reaction pressure was atmospheric pressure, and the reaction time was 4h to obtain 2-tert-butyl-p-cresol. The conversion rate of p-cresol was 89%, and the yield of 2-tert-butyl-p-cresol was 80%.

[0035] Example 3 Weigh 10g of TiO2 metal oxide and 0.3g of phosphotungstic acid (HPA) into a beaker, then add 50g of distilled water, sonicate for 4h, soak for 6h, filter, dry in an oven at 80℃ for 10h, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 300℃ for 5h to obtain a catalyst with an HPA loading of 3% (mass fraction), denoted as 3%HPA / TiO2.

[0036] Cresol and tert-butanol were mixed in a molar ratio of 1:2. The mass percentage of 3% HPA / TiO2 catalyst added was 2% of the mass of p-cresol. The reaction temperature was 100℃, the reaction pressure was atmospheric pressure, and the reaction time was 6h to obtain 2-tert-butyl-p-cresol. The p-cresol conversion rate was 87%, and the 2-tert-butyl-p-cresol yield was 76%.

[0037] Example 4 Weigh 10g of TiO2 metal oxide and 1.2g of phosphotungstic acid (HPA) into a beaker, then add 100g of distilled water, sonicate for 8 hours, soak for 4 hours, filter, dry in an oven at 100℃ for 5 hours, and finally put the ground white solid into a crucible and dry in an oven at 100℃ for 5 hours to obtain a catalyst with an HPA loading of 12% (mass fraction), denoted as 12%HPA / TiO2.

[0038] Cresol and tert-butanol were mixed in a molar ratio of 1:1.5. The mass percentage of 12% HPA / TiO2 catalyst added was 5% of the mass of p-cresol. The reaction temperature was 120℃, the reaction pressure was atmospheric pressure, and the reaction time was 3h to obtain 2-tert-butyl-p-cresol. The conversion rate of p-cresol was 91%, and the yield of 2-tert-butyl-p-cresol was 80%.

[0039] Example 5 Weigh 10g of ZrO2 metal oxide and 0.8g of phosphotungstic acid (HPA) into a beaker, then add 200g of distilled water, sonicate for 6h, impregnate for 6h, filter, dry in an oven at 90℃ for 6h, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 300℃ for 8h to obtain a catalyst with an HPA loading of 8% (mass fraction), denoted as 8%HPA / ZrO2.

[0040] Cresol and tert-butanol were mixed in a molar ratio of 1:1.4. The mass percentage of 12% HPA / TiO2 catalyst added was 6% of the mass of p-cresol. The reaction temperature was 110℃, the reaction pressure was atmospheric pressure, and the reaction time was 6h to obtain 2-tert-butyl-p-cresol. The p-cresol conversion rate was 92%, and the 2-tert-butyl-p-cresol yield was 82%.

[0041] Example 6 Weigh 5g of ZrO2 metal oxide and 0.75g of phosphotungstic acid (HPA) into a beaker, then add 100g of distilled water, sonicate for 4 hours, soak for 10 hours, filter, dry in an oven at 100℃ for 5 hours, and finally put the ground white solid into a crucible and dry in an oven at 400℃ for 6 hours to obtain a catalyst with an HPA loading of 15% (mass fraction), denoted as 15%HPA / ZrO2.

[0042] Cresol and tert-butanol were mixed in a molar ratio of 1:1.1. 15% HPA / ZrO2 catalyst was added at a mass percentage of 2% of the cresol. The reaction temperature was 110℃, the reaction pressure was atmospheric pressure, and the reaction time was 4h to obtain 2-tert-butyl-p-cresol. The conversion rate of p-cresol was 93%, and the yield of 2-tert-butyl-p-cresol was 82%.

[0043] Example 7 8.509 g (0.025 mol) of tetrabutyl titanate and 9.5918 g (0.025 mol) of zirconium n-butoxide were added to 333 mL of n-butanol and stirred continuously for 3 h until completely dissolved. Then, 160 mL of 5% ammonia solution was added dropwise using a peristaltic pump and stirring was continued for 5 h. The mixture was filtered and washed twice with distilled water. The white solid Ti(OH)4-Zr(OH)4 obtained by filtration was placed in an oven at 80 °C and dried for 5 h. Finally, the ground white solid was placed in a crucible and calcined in a muffle furnace at 600 °C for 3 h to obtain the metal composite oxide T5Z5O with a molar ratio of 5:5. Weigh 3g of metal composite oxide T5Z5O and 0.15g of phosphotungstic acid (HPA) into a beaker, then add 30g of distilled water, sonicate for 4h, soak for 6h, filter, dry in an oven at 100℃ for 4h, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 500℃ for 4h to obtain a catalyst with an HPA loading of 5% (mass fraction), denoted as 5%HPA / T5Z5O.

[0044] Cresol and tert-butanol were mixed in a molar ratio of 1:1.5. 5% HPA / T5Z5O catalyst was added at a mass percentage of 2% of the p-cresol. The reaction temperature was 120℃, the reaction pressure was atmospheric pressure, and the reaction time was 5 h to obtain 2-tert-butyl-p-cresol. The p-cresol conversion rate was 95%, and the 2-tert-butyl-p-cresol yield was 86%.

[0045] Example 8 13.614 g (0.04 mol) of tetrabutyl titanate and 3.837 g (0.01 mol) of zirconium n-butoxide were added to 400 mL of n-butanol and stirred continuously for 2 h until completely dissolved. Then, 80 mL of 10% ammonia solution was added dropwise using a peristaltic pump and stirring was continued for 4 h. The mixture was filtered and washed twice with distilled water. The white solid Ti(OH)4-Zr(OH)4 obtained by filtration was placed in an oven at 100 °C and dried for 3 h. Finally, the ground white solid was placed in a crucible and calcined in a muffle furnace at 700 °C for 3 h to obtain the metal composite oxide T8Z2O with a molar ratio of 8:2. Weigh 3g of metal composite oxide T8Z2O and 0.3g of phosphotungstic acid (HPA) into a beaker, then add 60g of distilled water, sonicate for 5h, soak for 5h, filter, dry in an oven at 80℃ for 6h, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 400℃ for 4h to obtain a catalyst with an HPA loading of 10% (mass fraction), denoted as 10%HPA / T8Z2O.

[0046] Cresol and tert-butanol were mixed in a molar ratio of 1:1.1. 10% HPA / T8Z2O catalyst was added at a mass percentage of 2% of the cresol. The reaction temperature was 110℃, the reaction pressure was atmospheric pressure, and the reaction time was 3 h to obtain 2-tert-butyl-p-cresol. The conversion rate of p-cresol was 98%, and the yield of 2-tert-butyl-p-cresol was 89%.

[0047] Example 9 10.211 g (0.03 mol) of tetrabutyl titanate and 7.673 g (0.02 mol) of zirconium n-butoxide were added to 400 mL of n-butanol and stirred continuously for 4 h until completely dissolved. Then, 160 mL of 5% ammonia solution was added dropwise using a peristaltic pump and stirring was continued for 5 h. The mixture was filtered and washed three times with distilled water. The white solid Ti(OH)4-Zr(OH)4 obtained by filtration was dried in an oven at 90 °C for 5 h. Finally, the ground white solid was placed in a crucible and calcined in a muffle furnace at 600 °C for 4 h to obtain the metal composite oxide T6Z4O with a molar ratio of 6:4. Weigh 3g of metal composite oxide T6Z4O and 0.24g of phosphotungstic acid (HPA) into a beaker, then add 60g of distilled water, sonicate for 5h, impregnate for 5h, filter, dry in an oven at 90℃ for 5h, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 300℃ for 4h to obtain a catalyst with an HPA loading of 8% (mass fraction), denoted as 8%HPA / T6Z4O.

[0048] Cresol and tert-butanol were mixed in a molar ratio of 1:1.2. An 8% HPA / T6Z4O catalyst was added at a mass percentage of 3% of the p-cresol. The reaction temperature was 110℃, the reaction pressure was atmospheric pressure, and the reaction time was 4h to obtain 2-tert-butyl-p-cresol. The p-cresol conversion rate was 96%, and the 2-tert-butyl-p-cresol yield was 87%.

[0049] Example 10 6.807 g (0.02 mol) of tetrabutyl titanate and 11.510 g (0.03 mol) of zirconium n-butoxide were added to 400 mL of n-butanol and stirred continuously for 3 h until completely dissolved. Then, 80 mL of 10% ammonia solution was added dropwise using a peristaltic pump and stirring was continued for 4 h. The mixture was filtered and washed three times with distilled water. The white solid Ti(OH)4-Zr(OH)4 obtained by filtration was placed in an oven at 100 °C and dried for 4 h. Finally, the ground white solid was placed in a crucible and calcined in a muffle furnace at 700 °C for 3 h to obtain the metal composite oxide T4Z6O with a molar ratio of 4:6. Weigh 3g of metal composite oxide T4Z6O and 0.36g of phosphotungstic acid (HPA) into a beaker, then add 45g of distilled water, sonicate for 4h, impregnate for 6h, filter, dry in an oven at 80℃ for 6h, and finally put the ground white solid into a crucible and calcine in a muffle furnace at 400℃ for 3h to obtain a catalyst with an HPA loading of 12% (mass fraction), denoted as 12%HPA / T4Z6O.

[0050] Cresol and tert-butanol were mixed in a molar ratio of 1:2. 12% HPA / T4Z6O catalyst was added at a mass percentage of 5% of the p-cresol. The reaction temperature was 110℃, the reaction pressure was atmospheric pressure, and the reaction time was 5 h to obtain 2-tert-butyl-p-cresol. The p-cresol conversion rate was 98%, and the 2-tert-butyl-p-cresol yield was 88%.

[0051] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A catalyst for the synthesis of 2-tert-butyl-p-cresol, characterized in that, The catalyst for the synthesis of 2-tert-butyl-p-cresol is phosphotungstic acid supported on a metal oxide. The metal oxide is one of SiO2, TiO2 and ZrO2, or a metal composite oxide of ZrO2 and TiO2.

2. The catalyst for synthesizing 2-tert-butyl-p-cresol according to claim 1, characterized in that, The mass of the phosphotungstic acid is 3% to 15% of the mass of the metal oxide.

3. A method for preparing a catalyst for synthesizing 2-tert-butyl-p-cresol as described in claim 1 or 2, characterized in that, Includes the following steps: A mixed solution is obtained by mixing metal oxide, phosphotungstic acid, and water. The mixed solution was subjected to ultrasonication, impregnation, filtration and drying in sequence to obtain a solid product; The solid product was calcined to obtain a catalyst for the synthesis of 2-tert-butyl-p-cresol.

4. The method for preparing a catalyst for synthesizing 2-tert-butyl-p-cresol according to claim 3, characterized in that, The mass ratio of metal oxide to water in the mixed solution is 5% to 20%.

5. The method for preparing a catalyst for synthesizing 2-tert-butyl-p-cresol according to claim 3, characterized in that, The phosphotungstic acid added is 3% to 15% of the mass of the metal oxide.

6. The method for preparing a catalyst for synthesizing 2-tert-butyl-p-cresol according to claim 3, characterized in that, The ultrasonic treatment time is 3-10 hours, the immersion time is 4-10 hours, the drying temperature is 70-100℃, and the drying time is 5-10 hours. The calcination process is carried out at a temperature of 300-500℃ for 3-8 hours.

7. The method for preparing a catalyst for synthesizing 2-tert-butyl-p-cresol according to claim 3, characterized in that, The preparation method of the ZrO2 and TiO2 metal composite oxide is as follows: S1: Add tetrabutyl titanate and zirconium n-butoxide to n-butanol, and stir to obtain a mixed solution; S2: Then add ammonia solution dropwise to the mixed solution to adjust the pH value, and continue stirring; S3: After filtering and washing the stirred solution, a solid is obtained; the solid is then dried, ground, and calcined to obtain a metal composite oxide of ZrO2 and TiO2, denoted as T. x Z y O; where X is 2~8 and Y is 2~8.

8. The method for preparing a catalyst for synthesizing 2-tert-butyl-p-cresol according to claim 7, characterized in that, In S1, the concentrations of both n-butyl titanate and zirconium n-butoxide in the mixed solution are 0.01~0.1 mol / L; the stirring time is 2-10 h; in S2, the mass concentration of ammonia water is 5%~10%; the pH value is adjusted to 10~11; the stirring time is 4-10 h. In step S3, the drying temperature is 70-100℃ and the time is 2-8 hours; the calcination temperature is 600-800℃ and the time is 2-10 hours.

9. The use of the catalyst according to claim 1 or 2 in the synthesis of 2-tert-butyl-p-cresol, characterized in that, Includes the following steps: After mixing p-cresol and tert-butanol, the catalyst was added to carry out the reaction. After the reaction was completed, 2-tert-butyl-p-cresol was obtained.

10. The application of the catalyst according to claim 9 in the synthesis of 2-tert-butyl-p-cresol, characterized in that, The molar ratio of p-cresol to tert-butanol is 1:(1.1-3); the mass of the catalyst added is 0.2~20 wt.% of the mass of p-cresol. The reaction is carried out at a temperature of 90~120℃ for a time of 0.5~6h.