Catalyst, preparation method thereof and application of catalyst in preparation of 2, 6-xylenol

Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a catalyst, a preparation method thereof and application of the catalyst in preparation of 2, 6-xylenol. The molar ratio of the iron element to the vanadium element to the platinum element in the catalyst is 100: (2-15): (0.05-0.5), and the preparation method of the catalyst is convenient and beneficial to industrial production. The catalyst provided by the invention has the characteristics of high conversion rate, high 2, 6-xylenol selectivity and high stability in a reaction for preparing 2, 6-xylenol and co-producing o-cresol through phenol methylation, the phenol conversion rate can reach 95% or above, and the 2, 6-xylenol selectivity can reach 90% or above.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis, specifically relating to a catalyst, its preparation method, and its application in the preparation of 2,6-xylenol. Background Technology

[0002] 2,6-Xylenol is an important chemical raw material and fine chemical intermediate. It can be used as a monomer for synthesizing engineering plastics polyphenylene oxide (PPO) and modified polyphenylene oxide, and it can also be used in the production of high-temperature epoxy resins and pesticides. Furthermore, it is a raw material and intermediate for some pharmaceuticals. Polyphenylene oxide is an excellent thermoplastic, one of the three major engineering plastics, and has a large market demand.

[0003] o-Cresol is an intermediate in the synthesis of pesticides, pharmaceuticals, resins, fragrances, and antioxidants. For example, o-cresol can be used to synthesize o-cresol phenolic resins, o-cresol phenolic epoxy resins, and phenoxycarboxylic acid herbicides (MCPA, MCPB, etc.). It can also be used to produce o-hydroxybenzaldehyde, dyes, fragrances, and antioxidants.

[0004] Early methods for synthesizing 2,6-xylenol and o-cresol involved obtaining them from coal tar and petroleum cracking products. However, due to limited resources, complex processes, and numerous separation units, these methods fell far short of the required standards. Among chemical synthesis methods, the diazotization hydrolysis of o-methylaniline suffers from drawbacks such as complex processes and intermittent production, making it unsuitable for large-scale production. The toluene chlorination hydrolysis method produces a large number of products with low purity. These processes also generally suffer from severe equipment corrosion and significant environmental pollution. The gas-phase alkylation of phenol and methanol offers advantages such as low production costs and environmental friendliness, making it the most advanced method for synthesizing o-cresol and 2,6-xylenol. The preparation of its catalyst is also a research hotspot in the field of catalysis.

[0005] In 1945, N. Cullinane et al. first synthesized 2,6-dimethylphenol by gas-phase catalytic methylation of phenol and methanol. MgO-based catalysts exhibited good catalytic activity in this reaction; for example, US patent applications US3446856A, US4041085A, US4201880A, and US4554267A all provided MgO-based catalysts. Although MgO-based catalysts showed good ortho-selectivity, a high proportion of para-methylated products with marginal effects were still produced, indicating that ortho-selectivity needs further improvement. More importantly, MgO-based catalysts are high-temperature catalysts, requiring very high reaction temperatures of 450℃-550℃, resulting in high energy consumption and poor catalyst stability. Due to the limitations of MgO-based catalysts in terms of energy consumption and catalytic activity, iron-based catalysts have gradually replaced magnesium-based catalysts. Iron-based catalysts have seen significant improvements in reducing reaction temperature, increasing the selectivity of ortho-methylation, and improving phenol conversion. For example, US patent applications US3716589A, US3953529A, US4024195A, and US4227024A all disclose iron-based catalysts. However, due to problems such as high preparation costs, stringent preparation and reaction conditions, and short catalyst lifespan, their industrial application remains unsatisfactory.

[0006] Several industrial catalysts with high phenol conversion and high 2,6-xylenol selectivity have been developed. Chinese patent CN116173974B discloses an iron-based catalyst supported on activated carbon, which is effective at a molar ratio of phenol, methanol, and water of 1:5:3 and a space velocity of 1 h⁻¹. -1 At a temperature of 380℃, the phenol conversion rate is 99.6%, and the selectivity for 2,6-dimethylphenol is 92.3%. However, this method requires a high alcohol-phenol ratio, resulting in material and energy waste and reducing the economic efficiency of the product. Patent CN100546716C discloses a catalyst synthesized using iron oxide, indium oxide, silicon dioxide, chromium oxide, calcium oxide, and alkali metal oxides, at a phenol:methanol:water molar ratio of 1:5:5 and a space velocity of 0.9 h⁻¹. -1 At a temperature of 360℃, the phenol conversion rate is 99%, the selectivity for 2,6-dimethylphenol is 97%, and the service life exceeds 3000 hours. However, this method also suffers from problems such as an excessively high alcohol-phenol ratio and low product economics, and the catalyst composition contains components such as chromium oxide that are unhealthy and environmentally unfriendly. Patent application CN117160465A discloses a catalyst using iron, germanium, aluminum, and alkali metals, with a molar ratio of phenol, methanol, and water of 1:5:3 and a liquid hourly space velocity of 0.8 h⁻¹. -1Under conditions of a nitrogen carrier gas flow rate of 10 mL / min and a reaction temperature of 350℃, after 2000 hours of reaction, the phenol conversion rate decreased from 99% to 95%, and the 2,6-xylenol selectivity decreased from 97.6% to 95.5%. The reaction performance declined with prolonged reaction time. This reaction also used a high alcohol-to-phenol ratio feedstock, thus reducing the product's economic viability. Patent application CN119346093A mentions mixing iron salts, aluminum salts, magnesium salts, acidic substances, and water to obtain solution A; mixing sodium silicate, a template agent, and water to obtain solution B; further processing the slurry obtained from mixing the two solutions yields a catalyst with a phenol:methanol:water molar ratio of 1:2.5:0.3 and a liquid hourly space velocity of 1.2 h⁻¹. -1 The carrier gas nitrogen flow rate was 15 mL / min, the reaction temperature was 310℃, and after 2500 hours of reaction, the phenol conversion rate was 95.2%, and the selectivity for 2,6-xylenol was 80.7%. The preparation steps of this catalyst are relatively complicated, and the selectivity for xylenol is also relatively low.

[0007] In summary, existing catalysts suffer from drawbacks such as low phenol conversion and low 2,6-xylenol selectivity under low alcohol-phenol ratio conditions. Therefore, there is an urgent need to develop a catalyst with high phenol conversion and high 2,6-xylenol selectivity under low alcohol-phenol ratio conditions. Summary of the Invention

[0008] To address the problems existing in the prior art, this invention proposes a catalyst for the gas-phase catalytic methylation reaction of phenol and methanol to synthesize 2,6-xylenol. The catalyst of this invention has a simple composition, mainly composed of iron salts, using trace amounts of the precious metal Pt and a small amount of vanadium salts. Its preparation method is convenient and conducive to industrial production. The catalyst of this invention exhibits high activity, achieving a selectivity of over 90% for the target product 2,6-xylenol at a relatively low alcohol-phenol feed ratio, while also possessing a high phenol conversion rate. The catalyst of this invention also exhibits high stability, maintaining a phenol conversion rate of over 95% and a 2,6-xylenol selectivity of over 90% after 2500 hours of catalytic operation.

[0009] Specifically, one aspect of the present invention provides a catalyst comprising iron, vanadium, and platinum, wherein the molar ratio of iron, vanadium, and platinum is 100:(2-15):(0.05-0.5).

[0010] In one or more embodiments, the Fe / V / Pt catalyst contains iron in the form of Fe2O3, vanadium in the form of V2O5, and platinum in the form of PtO2.

[0011] The present invention also provides a method for preparing the Fe / V / Pt catalyst according to any embodiment of the present invention, the method comprising the following steps:

[0012] (1) Dissolve the iron source and vanadium source in water, add a precipitant to precipitate, and then perform post-treatment to obtain intermediate powder;

[0013] (2) Add an auxiliary agent to the intermediate powder and calcine it for the first time to obtain the Fe / V support;

[0014] (3) The Fe / V support was loaded into a platinum source solution, dried, and then calcined a second time to obtain the Fe / V / Pt catalyst.

[0015] In one or more embodiments, the iron source is selected from one or more of ferric nitrate, ferric chloride, and ferric sulfate.

[0016] In one or more embodiments, the vanadium source is selected from one or more of ammonium metavanadate, vanadium oxalate, and ammonium vanadate.

[0017] In one or more embodiments, the platinum source is selected from one or more of chloroplatinic acid, bromoplatinic acid, hexahydroxyplatinic acid, and hexaammineplatinum chloride.

[0018] In one or more embodiments, the precipitant is ammonia.

[0019] In one or more embodiments, in step (2), the additive is selected from one or more of graphite, stearate, starch, carboxymethyl cellulose and methyl cellulose; preferably, the stearate is selected from one or more of calcium stearate, zinc stearate and magnesium stearate; preferably, the additive is graphite.

[0020] In one or more embodiments, in step (2), the mass ratio of the auxiliary agent to the intermediate powder is (0.1~3):100.

[0021] In one or more embodiments, in step (2), before the first calcination, the mixture of the intermediate powder and the additive is pressed into granules. Preferably, the granules are cylinders with a diameter of 4 to 6 mm and a thickness of 4 to 6 mm; more preferably, the granules are cylinders with a diameter of 5 mm and a thickness of 5 mm.

[0022] In one or more embodiments, in step (2), the temperature of the first roasting is 300°C to 500°C, and the time of the first roasting is 2 to 5 hours.

[0023] In one or more embodiments, in step (3), the Fe / V support obtained after the first calcination is immersed in a platinum source aqueous solution for 1 to 3 hours.

[0024] In one or more embodiments, in step (3), the drying temperature is 80°C to 150°C and the drying time is 6 to 12 hours.

[0025] In one or more embodiments, in step (3), the temperature of the second roasting is 250°C to 500°C, and the time of the second roasting is 2 to 5 hours.

[0026] In one or more embodiments, in step (1), the post-processing includes: aging the precipitate sequentially, filtering, first drying, pulverizing, washing, and second drying to obtain the intermediate powder.

[0027] In one or more embodiments, in step (1), the aging time is 1 to 5 hours.

[0028] In one or more embodiments, in step (1), the temperature of the first drying is 80°C to 150°C, and the time of the first drying is 6 to 12 hours.

[0029] In one or more embodiments, in step (1), the crushing is to crush the material obtained from the first drying to 60-80 mesh.

[0030] In one or more embodiments, in step (1), the washing is to wash the pulverized material with water until the conductivity of the water is less than 100 μS / m.

[0031] In one or more embodiments, in step (1), the temperature of the second drying is 80°C to 150°C, and the time of the second drying is 6 to 12 hours.

[0032] The present invention also provides a method for preparing 2,6-xylenol using the Fe / V / Pt catalyst described in any embodiment of the present invention or the Fe / V / Pt catalyst prepared using any embodiment of the present invention, the method comprising: contacting the Fe / V / Pt catalyst of the present invention with a material containing phenol and methanol to undergo a methylation reaction to generate 2,6-xylenol.

[0033] In one or more embodiments, the molar ratio of phenol to methanol in the phenol-methanol-containing material is 1:(2~5), preferably 1:(2~3), for example 1:2.5.

[0034] In one or more embodiments, the phenol and methanol-containing material further contains water, wherein the molar ratio of phenol to water is 1:(2~4).

[0035] In one or more embodiments, the methylation reaction is carried out at a temperature of 300°C to 400°C, preferably 335°C to 380°C.

[0036] In one or more embodiments, contacting the Fe / V / Pt catalyst with a material containing phenol and methanol comprises: loading the Fe / V / Pt catalyst into a reactor, introducing a mixed gas containing phenol and methanol, and carrying out a methylation reaction; preferably, the space velocity of the mixed gas containing phenol and methanol in the methylation reaction is 0.8~1.2 h⁻¹. -1 Preferably, the pressure of the pressure device in the methylation reaction is 0.1~0.5 MPa.

[0037] This invention provides the application of the Fe / V / Pt catalyst described in this invention or the Fe / V / Pt catalyst prepared by the method described in this invention in the preparation of 2,6-xylenol, or in improving the conversion rate of phenol and the selectivity of 2,6-xylenol.

[0038] In one or more embodiments, the raw materials for preparing 2,6-xylenol include phenol and methanol in a molar ratio of 1:(2~5), preferably 1:(2~3), for example 1:2.5.

[0039] The present invention has the following beneficial effects:

[0040] 1. The catalyst of the present invention has a simple composition, mainly Fe2O3, with a small amount of V2O5 and trace amounts of PtO2;

[0041] 2. The preparation method of the catalyst of the present invention is convenient and flexible, with low process cost and easy scale-up;

[0042] 3. The catalyst of the present invention has high catalytic activity and long lifespan. Under low alcohol-phenol ratio conditions, it achieves high phenol conversion rate (≥95%), and the selectivity of 2,6-xylenol reaches more than 90%, with a single-pass lifespan of up to 2500 h. Detailed Implementation

[0043] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used herein are explained and defined in general terms below. Unless otherwise specified, all technical and scientific terms used herein have the common meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0044] 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.

[0045] In this document, the terms “contains,” “includes,” “containing,” and similar terms encompass the meanings of “basically composed of” and “composed of.” For example, when this document discloses “A contains B and C,” “A is basically composed of B and C” and “A is composed of B and C” should be considered as having been disclosed in this document.

[0046] 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.

[0047] Unless otherwise specified, percentages refer to mass percentages and proportions refer to mass ratios in this article.

[0048] In this article, the sum of the percentages of all components in the composition is 100%.

[0049] In this document, when describing embodiments or examples, it should be understood that it is not intended to limit the invention to those embodiments or examples. Rather, all alternatives, modifications, and equivalents of the methods and materials described herein are covered within the scope of this invention.

[0050] 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.

[0051] In this article, o-cresol refers to o-methylphenol; 2,6-xylenol refers to 2,6-dimethylphenol.

[0052] The Fe / V / Pt catalyst of the present invention contains iron, vanadium and platinum, and the molar ratio of iron, vanadium and platinum is 100:(2~15):(0.05~0.5).

[0053] In one or more embodiments, the Fe / V / Pt catalyst of the present invention has a molar ratio of iron to vanadium of 100:(2~15), for example 100:2, 100:2.8, 100:3, 100:4, 100:5, 100:5.6, 100:6, 100:7, 100:8, 100:8.3, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, 100:15.

[0054] In one or more embodiments, the Fe / V / Pt catalyst of the present invention has a molar ratio of iron to platinum of 100:(0.05-0.5), for example 100:0.05, 100:0.1, 100:0.2, 100:0.25, 100:0.3, 100:0.4, 100:0.5.

[0055] The Fe / V / Pt catalyst of the present invention is prepared by a two-component precipitation followed by platinum loading. In one or more embodiments, an iron source and a vanadium source are dissolved in water, a precipitant is added dropwise for co-precipitation, followed by aging, filtration, first drying, pulverization, washing, and second drying to obtain an intermediate powder; an additive is added to the intermediate powder, and a first calcination is performed to obtain a Fe / V support; the support is impregnated in an aqueous solution of a platinum source, and after drying and a second calcination, the Fe / V / Pt catalyst is obtained.

[0056] In this invention, the iron source is preferably one or more of ferric nitrate, ferric chloride, or ferric sulfate; the vanadium source is preferably one or more of ammonium metavanadate, vanadium oxalate, or ammonium vanadate; and the platinum source is one or more of chloroplatinic acid (i.e., chloroplatinic acid hexahydrate), bromoplatinic acid, hexahydroxyplatinic acid, and hexaammineplatinum chloride.

[0057] In this invention, vanadium plays a positive role in the catalyst: an appropriate amount of vanadium can increase the number and strength of acid sites on the catalyst surface, thereby enhancing catalyst activity. Simultaneously, it can mitigate the loss of activity of iron due to excessive reduction during the catalytic reaction, for example, by inhibiting Fe... 3+ Irreversible transformation to Fe 0 This improves the stability of the catalyst. When the vanadium content in the catalyst is too low, such as when the molar ratio of iron to vanadium is greater than 100:2 (i.e., the molar ratio of vanadium to iron is less than 2:100), the catalytic activity and stability of the catalyst will be significantly reduced. When the vanadium content in the catalyst is too high, such as when the molar ratio of iron to vanadium is less than 100:15 (i.e., the molar ratio of vanadium to iron is greater than 15:100), it will lead to increased catalyst cost, excessive carbon buildup in the reaction, and decreased catalyst stability, among other adverse effects. Therefore, in this invention, the molar ratio of iron to vanadium in the catalyst can be 100:(2-15), for example 100:2, 100:2.8, 100:3, 100:4, 100:5, 100:5.6, 100:6, 100:7, 100:8, 100:8.3, 100:9, 100:10, 100:11, 100:12, 100:13, 100:14, 100:15.

[0058] Platinum possesses excellent electron transport capabilities and surface adsorption properties, serving as an active site or synergistically interacting with iron to promote the adsorption and activation of the reaction substrate by the catalyst, lowering the activation energy and increasing the reaction rate. The synergistic effect of platinum and iron can also inhibit the sintering or loss of the active components of the catalyst, extending its lifespan. When the platinum content in the catalyst is too low, such as when the molar ratio of iron to platinum is greater than 100:0.05 (i.e., the molar ratio of platinum to iron is less than 0.05:100), the catalytic activity of the catalyst will decrease, and the reaction rate will be slowed down. Conversely, when the platinum content is too high, such as when the molar ratio of iron to platinum is less than 100:0.5 (i.e., the molar ratio of platinum to iron is greater than 0.5:100), it will lead to a significant increase in catalyst cost and a decrease in the selectivity of the target product, 2,6-xylenol, among other adverse effects. Therefore, in this invention, the molar ratio of iron to platinum in the catalyst is 100:(0.05-0.5), for example 100:0.05, 100:0.1, 100:0.2, 100:0.25, 100:0.3, 100:0.4, 100:0.5.

[0059] In this invention, the precipitant is ammonia water with a concentration of 20~30 wt%, for example 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt%, 30 wt%.

[0060] In this invention, the aging time is 1 to 5 hours, for example 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, and 4.5 h.

[0061] In this invention, the temperature of the first drying is 80℃~150℃, for example 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃; the drying time of the first drying is 6~12 hours, for example 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h.

[0062] In this invention, after the first drying, the dried material (i.e., the co-precipitate) is pulverized to 60-80 mesh for easy washing. If the co-precipitate particles are too small and can pass through an 80-mesh sieve, it indicates that the powder is too fine, which will lead to slow washing efficiency; if the co-precipitate particles are too large and cannot pass through a 60-mesh sieve, it indicates that the particles are too large, are encapsulated, and cannot be washed clean.

[0063] In this invention, the pulverized material is washed with water to remove unreacted iron, vanadium, or platinum sources from the pulverized material, as well as other ions produced by the reaction besides precipitates. The washing process continues until the conductivity of the washing waste liquid is below 100 μS / m.

[0064] In this invention, the temperature for the second drying is 80℃~150℃, for example, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 130℃, 140℃, or 150℃; the drying time for the second drying is 6~12 hours, for example, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, or 12 h. An intermediate powder is obtained after the second drying.

[0065] In this invention, before calcination, the additives and intermediate powders are thoroughly mixed and pressed into cylinders with a diameter of 4-6 mm and a thickness of 4-6 mm. The diameter of the particles can be 4 mm, 5 mm, or 6 mm, and the thickness can be 4 mm, 5 mm, or 6 mm. The particles are cylindrical and then calcined.

[0066] In some preferred embodiments, the particles are cylinders with a diameter of 5 mm and a thickness of 5 mm (Ф5x5 mm).

[0067] In this invention, the additive is selected from one or more of graphite, stearate, starch, carboxymethyl cellulose, and methyl cellulose. The stearate is selected from one or more of calcium stearate, zinc stearate, and magnesium stearate. In some preferred embodiments, the additive is graphite.

[0068] In this invention, the additives possess pore-forming and / or lubricating functions. Preferably, the additives possess both pore-forming and lubricating functions. The pore-forming function refers to the additive's decomposition into gases such as CO2 and H2O during high-temperature calcination, leaving pores in the catalyst structure. This increases the catalyst's porosity, exposes more active sites, and the larger pore volume provides better carbon-holding capacity, extending catalyst life. Additives with pore-forming functions include graphite, starch, carboxymethyl cellulose, and methyl cellulose. The lubricating function refers to reducing wear on the mold during pressing, allowing for better demolding of the pressed catalyst. Additives with lubricating functions include graphite and stearates.

[0069] In some preferred embodiments, the additive is graphite, which has lubricating and pore-forming functions. During calcination, graphite decomposes into CO2 and leaves pores, thereby increasing the porosity and permeability of the catalyst, which is beneficial for exposing more active sites without significantly affecting the catalyst composition. Graphite also has a lubricating effect, which can reduce pressing resistance and regulate the pore structure of the catalyst.

[0070] In this invention, the mass ratio of the additive to the intermediate powder is (0.1~3):100, for example 0.1:100, 0.15:100, 0.2:100, 0.25:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, 1.2:100, 1.25:100, 1.5:100, 1.75:100, 1.8:100, 2:100, 2.2:100, 2.25:100, 2.5:100, 2.75:100, 2.8:100, and 3:100.

[0071] In this invention, the temperature of the first roasting is 300℃~500℃, for example 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, 500℃; the first roasting time is 2~5 hours, for example 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h.

[0072] In the preparation method of the two components of the present invention, which first precipitates and then supports platinum, the first calcination includes step (3): impregnation, drying of the impregnated support, and second calcination to obtain the Fe / V / Pt catalyst of the present invention.

[0073] In this invention, the Fe / V support obtained after the first calcination is immersed in an aqueous solution of a platinum source to ensure that the platinum element is fully in contact with and loaded onto the support. The immersion time is 1 to 3 hours, for example, 1 h, 1.5 h, 2 h, 2.5 h, or 3 h.

[0074] In this invention, the impregnated carrier is dried. The temperature of the third drying is 80~150℃, for example 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 130℃, 140℃, 150℃; the time of the third drying is 6~12 hours, for example 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h.

[0075] In this invention, the second calcination temperature is 250℃~500℃ to obtain the Fe / V / Pt catalyst of this invention. The second calcination temperature can be 200℃, 220℃, 240℃, 250℃, 260℃, 280℃, 300℃, 320℃, 340℃, 350℃, 360℃, 370℃, 380℃, 390℃, 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃, or 500℃; the second calcination time is 2~5 hours, for example, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, or 5 h.

[0076] The Fe / V / Pt catalyst of this invention, or the Fe / V / Pt catalyst prepared according to any embodiment of this invention, can be used in the phenol-methanol gas-phase method to prepare o-cresol and 2,6-xylenol via methylation. The specific steps are as follows: The Fe / V / Pt catalyst of this invention is loaded into a reactor, and a mixture of phenol and methanol is introduced, followed by reaction at high temperature. During the phenol-methanol gas-phase method for preparing o-cresol and 2,6-xylenol, the main products of the methylation reaction are o-cresol and 2,6-xylenol, while a small amount of byproducts, such as p-cresol and 2,4,6-trimethylphenol, are generated.

[0077] In this invention, when using the Fe / V / Pt catalyst of this invention to prepare o-cresol and 2,6-xylenol, the molar ratio of phenol to methanol is 1:(2~5), preferably 1:(2~3), and can be 1:2, 1:2.5, 1:2.75, 1:2.8, 1:3, 1:4, 1:4.5, or 1:5.

[0078] In this invention, the material containing phenol and methanol also contains water, and the molar ratio of phenol to water is 1:(2~4), for example 1:2, 1:2.2, 1:2.25, 1:2.5, 1:2.75, 1:3, 1:3.2, 1:3.5, 1:3.7, 1:3.8, 1:4.

[0079] In this invention, the Fe / V / Pt catalyst of this invention or the Fe / V / Pt catalyst prepared according to any embodiment of this invention is brought into contact with a material containing phenol and methanol. This involves loading the Fe / V / Pt catalyst of this invention into a reactor, introducing a mixed gas containing phenol and methanol, and carrying out a methylation reaction at a high temperature.

[0080] In some preferred embodiments, the temperature of the methylation reaction is 300°C to 400°C, more preferably 335°C to 380°C, and can be 300°C, 320°C, 335°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, or 400°C.

[0081] In some preferred embodiments, the space velocity of the gas mixture containing phenol and methanol introduced during the methylation reaction is 0.8~1.2 h⁻¹. -1 It can be 0.8 h -1 0.9 h -1 1 h -1 1.1 h -1 1.2 h -1 .

[0082] In some preferred embodiments, the pressure of the pressure device in the methylation reaction is 0.1~0.5 MPa, which can be 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.45 MPa, or 0.5 MPa.

[0083] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the invention. The methods, reagents, and materials used in the embodiments and comparative examples are conventional methods, reagents, and materials in the art, unless otherwise stated. The starting material compounds in the embodiments and comparative examples are all commercially available.

[0084] In this invention, the formula for calculating the conversion rate of phenol is: Phenol conversion rate = molar amount of phenol converted / total molar amount of phenol before reaction × 100%;

[0085] In this invention, the formula for calculating the selectivity of o-cresol is: o-cresol selectivity = molar amount of o-cresol generated in the reaction / molar amount of phenol converted × 100%;

[0086] In this invention, the formula for calculating the selectivity of 2,6-xylenol is: 2,6-xylenol selectivity = molar amount of 2,6-xylenol generated in the reaction / molar amount of phenol converted × 100%.

[0087] Example 1

[0088] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 9.811 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain the intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into a Ф5x5 mm cylinder and calcined at 450℃ for 4 h to obtain the carrier.

[0089] (2) Preparation of Fe / V / Pt catalyst: 1.548 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation liquid for impregnation for 2 h. After loading was completed, it was dried at 120℃ for 12 h and then calcined at 300℃ for 3 h to obtain the catalyst.

[0090] The Fe / V / Pt catalyst prepared in this embodiment is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:2.8:0.1.

[0091] Example 2

[0092] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 29.06 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain the intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into a Ф5x5 mm cylinder and calcined at 450℃ for 5 h to obtain the carrier.

[0093] (2) Preparation of Fe / V / Pt catalyst: 1.548 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation solution for 2 h. After loading, it was dried at 120℃ for 12 h and calcined at 400℃ for 3 h to obtain the catalyst.

[0094] The Fe / V / Pt catalyst prepared in this embodiment is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:8.3:0.1.

[0095] Example 3

[0096] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 19.624 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain the intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into a Ф5x5 mm cylinder and calcined at 450℃ for 3 h to obtain the carrier.

[0097] (2) Preparation of Fe / V / Pt catalyst: 1.548 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation solution for 2 h. After loading, it was dried at 120℃ for 12 h and calcined at 400℃ for 3 h to obtain the catalyst.

[0098] The Fe / V / Pt catalyst prepared in this embodiment is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:5.6:0.1.

[0099] Example 4

[0100] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 9.811 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain the intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into a Ф5x5 mm cylinder and calcined at 450℃ for 3 h to obtain the carrier.

[0101] (2) Preparation of Fe / V / Pt catalyst: 3.097 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation solution for 2 h. After loading, it was dried at 120℃ for 12 h and calcined at 300℃ for 3 h to obtain the catalyst.

[0102] The Fe / V / Pt catalyst prepared in this embodiment is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:2.8:0.2.

[0103] Example 5

[0104] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 29.085 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into a Ф5x5 mm cylinder and calcined at 450℃ for 3 h to obtain the carrier.

[0105] (2) Preparation of Fe / V / Pt catalyst: 3.097 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation solution for 2 h. After loading, it was dried at 120℃ for 12 h and calcined at 300℃ for 3 h to obtain the catalyst.

[0106] The Fe / V / Pt catalyst prepared in this embodiment is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:8.3:0.2.

[0107] Example 6

[0108] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 52.65 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain the intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into a Ф5x5 mm cylinder and calcined at 450℃ for 4 h to obtain the carrier.

[0109] (2) Preparation of Fe / V / Pt catalyst: 7.77 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation solution for 2 h. After loading, it was dried at 120℃ for 12 h and calcined at 300℃ for 3 h to obtain the catalyst.

[0110] The Fe / V / Pt catalyst prepared in this embodiment is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:15:0.5.

[0111] Comparative Example 1

[0112] This comparative example prepares catalysts containing Fe, In, Si, Cr, Ca, and K elements.

[0113] 500 g of ferric nitrate nonahydrate, 30 g of indium trichloride tetrahydrate, 5 g of chromium nitrate nonahydrate, 3 g of sodium silicate nonahydrate, and 0.6 g of calcium chloride dihydrate were dissolved in 10 kg of water. The solution was first neutralized with 10 wt% ammonia water until the pH reached 7.0, and then further adjusted to 7.8 with another 10 wt% ammonia water. The mixture was stirred for 1 h and then allowed to stand for 12 h to age. The precipitate was filtered, washed with water, and dried at 180 °C for 6 h. The dried precipitate was pulverized into 8-10 mesh particles, placed in 200 mL of 0.5 wt% K₂CO₃ solution, and impregnated at room temperature for 16 h. After filtration, the resulting particles were dried at 150 °C for 6 h and then calcined in a calcining furnace at 480 °C for 5 h. Finally, 1 g of graphite was added to the calcined material, and after thorough mixing, it was pressed into a cylinder with a diameter of Ф5x5 mm to obtain a catalyst composed of iron oxide, indium oxide, silicon dioxide, chromium oxide, calcium oxide, potassium oxide and graphite. The molar ratio of each component in the catalyst was Fe2O3:In2O3:SiO2:CrO2:CaO:K2O:C=100:8.2:0.85:1.0:0.44:0.15:3.4.

[0114] Comparative Example 2

[0115] This comparative example prepares catalysts containing Fe and Bi elements.

[0116] Activated carbon dioxide treatment process: Weigh 200 g of coconut shell activated carbon and place it in a 500 mL high-pressure reactor lined with polytetrafluoroethylene. Slowly add 100 mL of concentrated sulfuric acid to disperse the coconut shell activated carbon evenly and seal the reactor. Allow it to stand in an oven at 160℃ for 90 min for sulfonation reaction. After the reaction is completed and cooled to room temperature, slowly pour the mixture into a beaker containing a large amount of deionized water and collect the solid by vacuum filtration. Wash the solid with deionized water at 80℃ until neutral, and then dry it overnight in an oven at 110℃ to obtain the activated carbon carrier.

[0117] 101.0 g Fe(NO3)3·9H2O and 0.4937 g Bi(NO3)3·5H2O were completely dissolved in 200 mL of water, and 200 g of activated carbon support was added. The mixture was left to stand overnight at room temperature, and then dried at 100 °C for 24 h. The collected solid was calcined in a muffle furnace at 500 °C for 5 h to obtain the catalyst.

[0118] Comparative Example 3

[0119] This comparative example prepares catalysts containing Fe, Al, Ge, and K elements.

[0120] 100 g of Fe(NO3)3·9H2O and 1.39 g of Al(NO3)3·9H2O were completely dissolved in 1000 mL of deionized water to obtain solution A. 0.385 g of GeO2 was dissolved in 20 g of 20 wt% NaOH solution at 40℃ to obtain solution B. Solution B was added dropwise to solution A and stirred thoroughly until homogeneous. Under stirring, 10 wt% ammonia solution was added dropwise to induce a co-precipitation reaction until the pH of the reaction system reached 7.0, at which point the addition of ammonia solution was stopped. The mixture was aged by stirring at room temperature for 2 h. The resulting precipitate was washed with water and filtered to obtain a filter cake. 0.17 g of potassium carbonate was dissolved in 200 mL of deionized water to prepare a solution. The filter cake was dispersed in the potassium carbonate solution and impregnated with an equal volume. The mixture was stirred for 0.5 h, then allowed to stand for 12 h, dried at 150℃ for 8 h, and then calcined at 500℃ for 6 h to obtain the catalyst.

[0121] Comparative Example 4

[0122] This comparative example prepares catalysts containing Fe, Al, Mg, Cu, Na, and Si elements.

[0123] (1) Dissolve 80.8 g of Fe(NO3)3·9H2O, 37.5 g of Al(NO3)3·9H2O, 25.6 g of Mg(NO3)2·6H2O and 107 g of ammonium chloride in 500 g of water to obtain solution C;

[0124] (2) Dissolve 568 g of Na2SiO3·9H2O and 5 g of tetrapropylammonium hydroxide (TPAOH) in 1500 g of water to obtain solution D;

[0125] (3) Slowly add solution C to solution D at room temperature with stirring to obtain a reaction slurry. Heat to 50°C, stir and keep warm for 1 h to obtain the slurry.

[0126] (4) The slurry was transferred to a 10 L hydrothermal reactor and crystallized at 200 °C for 12 h. During this period, the mixture was slowly stirred for 5 min every 2 h to mix the solid and liquid phases. After the reaction was completed, the solid was obtained by filtration and washing. After drying, it was calcined in a muffle furnace at 540 °C for 6 h. Large catalyst particles larger than 100 mesh were removed by sieving to obtain catalyst precursor one.

[0127] (5) Catalyst precursor one was suspended in a 0.2 mol / L NaOH solution and stirred at 80°C for 3 h to obtain a mixture. After the mixture cooled, it was washed with deionized water and then dried at 110°C to obtain catalyst precursor two;

[0128] (6) Catalyst precursor II was acid-treated in a 15 wt% oxalic acid solution and stirred at 90 °C for 4 h. The solid was collected by filtration and washed repeatedly with distilled water until the acid was completely removed. The solid was filtered out and dried at 90 °C, and finally calcined at 550 °C for 1 h to obtain the catalyst.

[0129] (7) Dissolve 12.1 g of Cu(NO3)2·3H2O in 200 g of water to obtain a copper nitrate solution. Add the catalyst to the copper nitrate solution, stir and mix well, then add 1 wt% NaOH aqueous solution until the pH of the solution is 13. Keep stirring and sonicate the system for 15 min. Seal the container at room temperature and let it stand for 4 h. Pour out the liquid in the container to obtain a solid substance. Wash the solid substance with deionized water until the aqueous solution is neutral. Then calcine at 550℃ for 3 h. Press the obtained powder solid into tablets and crush them. Use a sieve to separate 40-60 mesh particles and store them in a desiccator to obtain the loaded catalyst.

[0130] Comparative Example 5

[0131] This comparative example uses a method of first preparing a support and then loading Pt to prepare the Fe / V / Pt catalyst:

[0132] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 9.811 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into cylinders with a diameter of Ф5x5 mm and calcined at 450℃ for 4 h to obtain the carrier.

[0133] (2) Preparation of Fe / V / Pt catalyst: 0.155 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation solution for 2 h. After loading was completed, it was dried and calcined at 300℃ for 3 h to obtain the catalyst.

[0134] The Fe / V / Pt catalyst prepared in this comparative example is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:2.8:0.01.

[0135] Comparative Example 6

[0136] This comparative example uses a method of first preparing a support and then loading Pt to prepare the Fe / V / Pt catalyst:

[0137] (1) Preparation of the carrier: 1210 g of ferric nitrate nonahydrate and 3.504 g of ammonium metavanadate were dissolved in 10 kg of deionized water at 70℃. After dissolution, 900 g of ammonia water (concentration of 25wt%) was added dropwise until complete precipitation. The mixture was aged at room temperature for 3 h, filtered, and dried at 120℃ for 12 h. After drying, the mixture was pulverized and washed until the conductivity was below 100 μS / m. It was then dried at 120℃ for 12 h to obtain intermediate powder. Graphite was added to the obtained intermediate powder to make the mass ratio of graphite to intermediate powder 0.8:100. After thorough mixing, the mixture was pressed into cylinders with a diameter of Ф5x5 mm and calcined at 450℃ for 4 h to obtain the carrier.

[0138] (2) Preparation of Fe / V / Pt catalyst: 1.548 g of chloroplatinic acid was completely dissolved in 75 g of deionized water. The shaped support was placed in a flask containing impregnation solution for 2 h. After loading was completed, it was dried and calcined at 300℃ for 3 h to obtain the catalyst.

[0139] The Fe / V / Pt catalyst prepared in this comparative example is composed of Fe2O3, V2O5 and PtO2. The molar ratio of iron, vanadium and platinum in the Fe / V / Pt catalyst is 100:1.0:0.1.

[0140] Test case

[0141] I. Performance Evaluation Experiment of Catalyst in the Synthesis of 2,6-Xylenol

[0142] In the following experiments, the catalyst particles were pulverized to a mesh size of 12-20 before being added to the reactor. TOS represents the contact time between the catalyst and the material, which is the catalyst reaction time. This invention uses chromatographic analysis to detect the content of each substance before and after catalytic synthesis, and further calculates the phenol conversion rate and product selectivity.

[0143] Experimental Condition 1:

[0144] 2,6-Xylenol was prepared from phenol and methanol via a gas-phase method in a fixed-bed reactor with an inner diameter of φ=13mm. 5 g of catalyst (12-20 mesh) from each of the examples and comparative examples was loaded into the reaction tube, with the catalyst bed located in the isothermal section of the heater. Phenol, methanol, and water were prepared into a reaction solution at a molar ratio of 1:5:3 (high alcohol-phenol ratio). The reaction solution was first vaporized in a gasifier using a metering pump before being introduced into the reactor. The reactor was heated to 350℃, the reaction pressure was 0.3 MPa, and the reaction space velocity was 1.0 h⁻¹. -1 After reacting for 2500 h (i.e., TOS = 2500 h), the product was collected by cooling and analyzed offline by gas chromatography. The corresponding phenol conversion, o-cresol selectivity, and 2,6-xylenol selectivity data are shown in Table 1.

[0145] Table 1: Performance of the catalyst in the synthesis of 2,6-xylenol under experimental condition 1

[0146]

[0147] Experimental condition 2:

[0148] The difference from experimental condition 1 is that the molar ratio of phenol, methanol, and water in the reaction solution is 1:2.5:3 (low alcohol-phenol ratio), while other conditions are the same as experimental condition 1. The corresponding phenol conversion rate, o-cresol selectivity, and 2,6-xylenol selectivity data are shown in Table 2.

[0149] Table 2: Performance of the catalyst in the synthesis of 2,6-xylenol under experimental condition 2

[0150]

[0151] II. Performance Evaluation Experiments of Catalysts in the Synthesis of 2,6-Xylenol under Different TOS Durations

[0152] 2,6-Xylenol was prepared from phenol and methanol via a gas-phase method in a fixed-bed reactor with an inner diameter of φ = 13 mm. The Fe / V / Pt catalyst prepared in Example 5 and the catalyst prepared in Comparative Example 6 were pulverized and sieved to obtain 12-20 mesh particles, which were then added to the reactor, positioning the catalyst bed in the isothermal section of the heater. The reactor was heated to 350°C, and a reaction solution was prepared by mixing phenol, methanol, and water in a molar ratio of 1:2.5:3 (low alcohol-phenol ratio). This solution was then vaporized in a gasifier using a metering pump and subsequently introduced into the reactor. The reaction pressure was set at 0.2 MPa, and the reaction space velocity was 1.0 h⁻¹. -1The catalysts were reacted with the Fe / V / Pt catalyst of Example 5 and the catalyst of Comparative Example 6, respectively. After TOS of 2500 h and 4000 h, the products were collected by cooling and analyzed offline by gas chromatography. The phenol conversion, o-cresol selectivity and 2,6-xylenol selectivity of the two catalysts are shown in Tables 3 and 4.

[0153] Table 3: Performance of the catalyst in Example 5 at different TOS durations in the synthesis of 2,6-xylenol

[0154]

[0155] Table 4: Performance of the catalyst of Comparative Example 6 at different TOS durations in the synthesis of 2,6-xylenol

[0156]

Claims

1. A Fe / V / Pt catalyst characterized in that, The Fe / V / Pt catalyst contains iron element, vanadium element and platinum element, and the molar ratio of the iron element, the vanadium element and the platinum element is 100:(2-15):(0.05-0.5).

2. The Fe / V / Pt catalyst of claim 1, wherein In the Fe / V / Pt catalyst, the iron element exists in the form of Fe2O3, the vanadium element exists in the form of V2O5, and the platinum element exists in the form of PtO2.

3. Process for the preparation of the Fe / V / Pt catalyst according to claim 1 or 2, characterized in that, The method comprises the following steps: (1) dissolving an iron source and a vanadium source in water, adding a precipitant for precipitation, and obtaining an intermediate powder through post-treatment; (2) adding an additive to the intermediate powder, and obtaining the Fe / V carrier through first calcination; (3) loading the Fe / V carrier into a platinum source solution, drying, and obtaining the Fe / V / Pt catalyst through second calcination.

4. The method of claim 3, wherein, The method has one or more of the following characteristics: The iron source is selected from one or more of ferric nitrate, ferric chloride and ferric sulfate; The vanadium source is selected from one or more of ammonium metavanadate, vanadous oxalate and ammonium vanadate; The platinum source is selected from one or more of chloroplatinic acid, bromoplatinic acid, hexahydroxyplatinic acid and hexammineplatinum chloride; The precipitant is ammonia water; In step (2), the additive is selected from one or more of graphite, stearate, starch, carboxymethyl cellulose and methyl cellulose; preferably, the stearate is selected from one or more of calcium stearate, zinc stearate and magnesium stearate; preferably, the additive is graphite; In step (2), the mass ratio of the additive to the intermediate powder is (0.1-3):100; In step (2), before the first calcination, the mixture of the intermediate powder and the additive is pressed into a particle; preferably, the particle is a cylinder with a diameter of 4-6 mm and a thickness of 4-6 mm; more preferably, the particle is a cylinder with a diameter of 5 mm and a thickness of 5 mm; In step (2), the temperature of the first calcination is 300-500°C, and the time of the first calcination is 2-5 hours; In step (3), the Fe / V carrier obtained after the first calcination is immersed in an aqueous platinum source solution for 1-3 hours; In step (3), the temperature of the drying is 80-150°C, and the time of the drying is 6-12 hours; In step (3), the temperature of the second calcination is 250-500°C, and the time of the second calcination is 2-5 hours.

5. The method of claim 3, wherein, In step (1), the post-treatment comprises: sequentially aging, filtering, first drying, crushing, washing and second drying the precipitate, thereby obtaining the intermediate powder.

6. The method of claim 5, wherein, The method has one or more of the following characteristics: In step (1), the time of the aging is 1-5 hours; In step (1), the temperature of the first drying is 80-150°C, and the time of the first drying is 6-12 hours; In step (1), the crushing is crushing the material obtained after the first drying to 60-80 mesh; In step (1), the washing is washing the crushed material with water until the conductivity of the water is lower than 100 μS / m; In step (1), the second drying is performed at a temperature of 80-150°C for 6-12 hours.

7. A process for the preparation of 2,6-dimethylphenol, characterized in that, The method comprises contacting the Fe / V / Pt catalyst of claim 1 or 2 or the Fe / V / Pt catalyst prepared by the method of claim 3 or 4 with a material containing phenol and methanol to generate 2,6-dimethylphenol by methylation.

8. The method of claim 7, wherein, The method has one or more of the following features: The material containing phenol and methanol has a molar ratio of phenol to methanol of 1:(2-5), preferably 1:(2-3), for example 1:2.5; The material containing phenol and methanol also contains water, and the molar ratio of phenol to water is 1:(2-4); The methylation reaction is performed at a temperature of 300-400°C, preferably 335-380°C; The Fe / V / Pt catalyst is contacted with a material containing phenol and methanol, which includes: loading the Fe / V / Pt catalyst into a reactor, introducing a mixed gas containing phenol and methanol, and performing a methylation reaction; preferably, the space velocity of the mixed gas containing phenol and methanol in the methylation reaction is 0.8-1.2 h -1 ; preferably, the pressure of the pressure vessel in the methylation reaction is 0.1-0.5 MPa.

9. Use of the Fe / V / Pt catalyst of claim 1 or 2 or the Fe / V / Pt catalyst prepared by the method of claim 3 or 4 in the preparation of 2,6-dimethylphenol.

10. Use according to claim 9, wherein the compound is ###0002### The raw materials for preparing 2,6-dimethylphenol include phenol and methanol in a molar ratio of 1:(2-5), preferably 1:(2-3), for example 1:2.5.

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