A hydrogenation catalyst and preparation method thereof

Abstract

The present invention provides a hydrogenation catalyst, which includes a carrier and a catalytic active component, wherein the carrier includes α-Al2O3 and MgO, and the active component includes a platinum element. The present invention uses alumina of a specific crystal form as a core, coats a basic oxide, forms a composite carrier, and then loads a precious metal on the composite carrier to obtain a hydrogenation catalyst. The hydrogenation catalyst is applied to the reaction of hydrogenation and hydrogenolysis of dibenzofuran to produce OPP, and has the characteristics of high OPP selectivity, few by-products, good stability, and long service life. The active precious metal in the hydrogenation catalyst is more dispersed on the surface of the carrier, reducing the amount of the precious metal component. The preparation process of the hydrogenation catalyst is simple and easy to mass produce. Therefore, the hydrogenation catalyst provided by the present invention has excellent prospects for industrial application.

Description

Technical Field

[0001] The invention belongs to the field of catalysts, and in particular relates to a hydrogenation catalyst and a preparation method thereof. Background Art

[0002] At present, the main production processes used for industrial production of o-phenylphenol (OPP) are cyclohexanone dicondensation route and chlorobenzene high-pressure hydrolysis route. Among them, the cyclohexanone condensation dehydrogenation process was developed and used by Bayer in Germany. It has high requirements for equipment, uses concentrated sulfuric acid as a catalyst, and produces a large amount of acidic wastewater. Domestic companies mostly use this route. The chlorobenzene high-pressure hydrolysis route was developed by Dow Chemical Company in the United States. This process produces a large amount of by-products of p-phenylene ether and p-phenylphenol. The main product OPP is purified by recrystallization, and the purity is not high. There is a large amount of wastewater. In addition, this process has high requirements for the reaction equipment, which must be resistant to high pressure and corrosion.

[0003] The dibenzofuran hydrogenolysis route is an OPP production route with industrial development potential. This route uses dibenzofuran as a reaction raw material. Under hydrogen pressure conditions, a hydrogenation hydrogenolysis reaction occurs to obtain the main product OPP. There is no industrial device for this route yet. The processes under research mainly include a kettle reaction process using metal Na as a catalyst and a fixed bed reaction process using a loaded catalyst. The Na process has problems such as poor selectivity, difficult separation, and low safety. The fixed bed process mainly uses precious metal catalysts. At present, there are problems such as short catalyst life, high precious metal loading, low OPP selectivity, and complex preparation process, making it difficult to achieve industrialization.

[0004] CN104841421A discloses a catalyst composition for catalyzing the hydrogenation of dibenzofuran (dibenzofuran) to prepare o-phenylphenol, the catalyst composition comprises a hydrogenation catalyst active component and a carrier part, the active material in the hydrogenation catalyst active component is Pt or Pd; the carrier part is a solid carrier, and the solid carrier is selected from γ-Al2O3, θ-Al2O3, SiO2 or activated carbon. The active metal loading of the catalyst composition is relatively high (1-5%, and the noble metal loading in the embodiment is 2%), and the OPP selectivity is about 20-70%, so there are the disadvantages of high catalyst cost and low OPP selectivity.

[0005] CN105879862A discloses a method for preparing an eggshell-type precious metal catalyst and a method for preparing o-phenylphenol by hydrogenation and ring opening of dibenzofuran, wherein a carrier is added to a platinum metal salt solution, and platinum nanoparticles are controlled to deposit on the carrier surface through a rapid reduction reaction and solution viscosity, and then filtered, washed, and heated and dried in an inert atmosphere to form a stable eggshell-type platinum catalyst. During the preparation process, the method requires long-term (more than 30 days) aging of the active liquid (polyol solution of platinum metal salt), control of solution viscosity, use of an inducer, and drying in an inert atmosphere. The preparation method is complex, time-consuming, and energy-intensive, which is not conducive to industrial production; the amount of precious metal used is high (the optimal loading amount of precious metal is 1%), and the catalyst cost is high.

[0006] CN108947775A discloses a method for preparing o-phenylphenol by catalyzing the ring-opening of dibenzofuran, which uses industrial dibenzofuran as raw material, adopts nano-titanium oxide mesoporous composite material loaded with copper as hydrogenation catalyst, and the catalyst uses ordered mesoporous silicon oxide material / nano-titanium oxide mesoporous composite material as carrier, and the carrier is used to load metal copper. The method uses butyl titanate as titanium source, introduces it into the pores of ordered mesoporous silicon oxide material by sol-gel method, needs to be washed with a large amount of water and ethanol, and will produce a large amount of wastewater during industrial amplification, which has a great impact on environmental protection; when catalyzing the hydrogenation of dibenzofuran to prepare OPP, the product OPP selectivity is less than 33%, and most of the product is biphenyl, with low economic benefits.

[0007] It can be seen that the existing catalysts for preparing o-phenylphenol by hydrogenation of dibenzofuran have the problems of high cost, complex preparation process, low OPP selectivity, short life, etc. Therefore, the art needs a hydrogenation catalyst with low cost, simple preparation process, high OPP selectivity, good stability, long life, and industrial large-scale production. Summary of the invention

[0008] In order to solve the above problems, the present invention uses alumina of a specific crystal form as the core, coats basic oxides, forms a composite carrier, and then loads a noble metal salt on the composite carrier to obtain a hydrogenation catalyst. The catalyst is applied to the reaction of hydrogenation and hydrogenolysis of dibenzofuran to produce OPP, and has the characteristics of high OPP selectivity, few by-products, good stability, and long service life. The active noble metal in the catalyst is more dispersed on the surface of the carrier, reducing the amount of the noble metal component. The preparation process of the catalyst is simple and easy to mass produce. Therefore, the hydrogenation catalyst provided by the present invention has excellent prospects for industrial application.

[0009] Specifically, the present invention provides a hydrogenation catalyst or a precursor thereof, wherein the hydrogenation catalyst or the precursor thereof comprises a carrier and a catalytically active component, wherein the carrier comprises α-Al2O3 and MgO, and the active component comprises platinum.

[0010] In one or more embodiments, in the carrier, the mass of α-Al2O3 accounts for 70% to 96% of the total mass of the carrier, and the mass of MgO accounts for 4% to 30% of the total mass of the carrier.

[0011] In one or more embodiments, in the carrier, the mass of α-Al2O3 accounts for 76% to 95% of the total mass of the carrier, and the mass of MgO accounts for 5% to 24% of the total mass of the carrier.

[0012] In one or more embodiments, in the hydrogenation catalyst or its precursor, the mass of platinum element is 0.1% to 1% of the mass of the carrier, preferably 0.1% to 0.7%, and more preferably 0.1% to 0.6%.

[0013] In one or more embodiments, the MgO is located on the surface of the α-Al 2 O 3 .

[0014] In one or more embodiments, the α-Al 2 O 3 is in the form of particles having a particle size of 2 to 5 mm.

[0015] In one or more embodiments, the platinum element is present in the form of a soluble platinum-containing compound, platinum oxide, and / or metallic platinum.

[0016] The present invention also provides a method for preparing the hydrogenation catalyst precursor described in any embodiment of the present invention, the method comprising the following steps:

[0017] (1) loading a soluble magnesium-containing compound on the surface of α-Al2O3 and calcining to obtain the carrier;

[0018] (2) Loading a soluble platinum-containing compound on the surface of the carrier to obtain the hydrogenation catalyst precursor.

[0019] In one or more embodiments, the soluble magnesium-containing compound is selected from one or more of magnesium nitrate, magnesium acetate, and magnesium chloride.

[0020] In one or more embodiments, in step (1), the loading is performed using a sugar coater, a coating machine, a ball rolling machine or a rotary mixer, and the rotation speed of the sugar coater, the coating machine, the ball rolling machine or the rotary mixer is preferably 5 to 40 rpm.

[0021] In one or more embodiments, in step (1), the soluble magnesium-containing compound is loaded on the surface of α-Al2O3 by spraying or dipping.

[0022] In one or more embodiments, the calcination method in step (1) is: heating from room temperature to 500-700° C. at a heating rate of 3-10° C. / min, and then calcining for 2-8 hours.

[0023] In one or more embodiments, in step (1), before calcination, the α-Al2O3 loaded with the soluble magnesium-containing compound is dried, preferably at 60 to 120°C for 5 to 16 hours.

[0024] In one or more embodiments, the soluble platinum-containing compound is selected from one or more of chloroplatinic acid, tetraamineplatinum nitrate, and tetraamineplatinum chloride.

[0025] In one or more embodiments, in step (2), the loading is performed using a sugar coater, a coating machine, a ball rolling machine or a rotary mixer, and the rotation speed of the sugar coater, the coating machine, the ball rolling machine or the rotary mixer is preferably 5 to 40 rpm.

[0026] In one or more embodiments, in step (2), the soluble platinum-containing compound is loaded on the surface of the carrier by spraying or dipping.

[0027] In one or more embodiments, step (2) further comprises drying the carrier loaded with the soluble platinum-containing compound, and the drying is preferably carried out at 60 to 120° C. for 5 to 16 hours.

[0028] The present invention also provides a method for preparing the hydrogenation catalyst described in any embodiment herein, the method comprising the method for preparing the hydrogenation catalyst precursor described in any embodiment herein and the following steps:

[0029] (3) calcining the hydrogenation catalyst precursor to obtain the hydrogenation catalyst.

[0030] In one or more embodiments, the calcination method in step (3) is: heating from room temperature to 500-700° C. at a heating rate of 3-10° C. / min, and then calcining for 2-8 hours.

[0031] In one or more embodiments, the method for preparing a hydrogenation catalyst further comprises the following steps:

[0032] (4) reducing the hydrogenation catalyst obtained in step (3) at 350-450° C. for 2-6 hours.

[0033] The present invention also provides a method for catalytic hydrogenation reaction, which comprises catalytic hydrogenation reaction using the hydrogenation catalyst described in any embodiment of the present invention or the hydrogenation catalyst prepared by the method described in any embodiment of the present invention; preferably, the hydrogenation reaction is the reaction of hydrogenating dibenzofuran to prepare o-phenylphenol.

[0034] In one or more embodiments, the hydrogenation reaction is carried out in a fixed bed reactor.

[0035] In one or more embodiments, in the hydrogenation reaction, the dibenzofuran raw material is provided in the form of a dibenzofuran solution or molten dibenzofuran, the solvent of the dibenzofuran solution is preferably toluene, methylcyclohexane or a mixture thereof, and the dibenzofuran concentration of the dibenzofuran solution is preferably ≥20 wt%.

[0036] In one or more embodiments, in the hydrogenation reaction, the reaction temperature is 350-450°C.

[0037] In one or more embodiments, during the hydrogenation reaction, the hydrogen pressure is 0.3-5 MPa.

[0038] In one or more embodiments, in the hydrogenation reaction, the mass space velocity of dibenzofuran is 0.5 to 1.5 h -1 .

[0039] In one or more embodiments, in the hydrogenation reaction, the hydrogen-to-oil ratio is (600-3000):1.

[0040] The present invention also provides the use of α-Al2O3 in improving the selectivity and / or stabilizing the reactivity of o-phenylphenol in the reaction of hydrogenating dibenzofuran to prepare o-phenylphenol, or in preparing a hydrogenation catalyst for catalyzing the hydrogenation of dibenzofuran to prepare o-phenylphenol. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is the XRD spectrum of the catalyst of Example 4. Since the Pt content of the catalyst is too low and the dispersion is high, no Pt peak can be seen. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0043] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0044] Herein, “comprising”, “including”, “containing” and similar terms cover the meanings of “consisting essentially of” and “consisting of”, for example, when “A comprises B and C” is disclosed herein, “A consists of B and C” should be deemed to be disclosed herein.

[0045] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0046] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0047] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0048] In view of the problems of high cost, complex preparation process, low selectivity to OPP and short life of existing benzofuran hydrogenation catalysts, the present invention uses α-Al2O3 as the carrier core, coats the alkaline oxide, forms an alkaline composite carrier with low specific surface area, and then loads the precious metal salt on the composite carrier. The carrier with low specific surface area is conducive to more dispersion of active metals on the carrier surface, which not only improves the utilization efficiency of precious metals and reduces the loading amount of precious metal components, but also is conducive to the diffusion of reaction products, improves the selectivity of the main product OPP, and reduces the generation of subsequent by-products. In addition, the catalyst of the present invention has good stability and can stably operate for more than 1500 hours in a single pass.

[0049] The hydrogenation catalyst or its precursor of the present invention comprises a carrier and an active component, wherein the carrier comprises α-Al2O3 and MgO, and the active component comprises platinum element.

[0050] In the present invention, the carrier has the conventional meaning in the art, and is the support of the active components in the catalyst. The main body of the carrier contained in the hydrogenation catalyst of the present invention is α-Al2O3. The present invention has found that the use of α-Al2O3 with a lower specific surface area than other crystal forms to load the active components is conducive to the active metal being dispersed more on the outer surface of the carrier, reducing the amount of precious metals used; it is conducive to the diffusion of the reaction products and improving the OPP selectivity. The α-Al2O3 suitable for the present invention is preferably a granular α-Al2O3 with a particle size of 2 to 5 mm, for example, 2.5 to 4.5 mm, 3 to 4 mm. It is understood that when the particles are not spheres, the particle size described herein refers to the equivalent particle size of the particles. The shape of the α-Al2O3 particles can be strip-shaped, spherical, hollow, etc. In some embodiments, the present invention uses a strip-shaped α-Al2O3 with a diameter of 2.5 to 4.5 mm, 3±0.5 mm or 4±0.5 mm, or a spherical α-Al2O3 with a diameter of 3±0.5 mm, or a hollow α-Al2O3 with an outer diameter of 4±0.5 mm and an inner diameter of 1±0.5 mm. The carrier of the hydrogenation catalyst of the present invention or its precursor further comprises MgO. In the carrier of the present invention, MgO is present on the surface of α-Al2O3.

[0051] In the carrier of the hydrogenation catalyst or its precursor of the present invention, the total mass of α-Al2O3 and MgO can account for more than 90%, more than 95%, more than 98%, more than 99% or 100% of the total mass of the carrier. The mass of α-Al2O3 can account for 70% to 96% of the total mass of the carrier, preferably 76% to 95%, for example, it can be 76±1%, 80±1%, 84±1%, 92±1%, 95±1% or within the range of any two of these contents. The mass of MgO can account for 4% to 30% of the total mass of the carrier, preferably 5% to 24%, for example, it can be 5±1%, 8±1%, 16±1%, 20±1%, 24±1% or within the range of any two of these contents. The present invention finds that controlling the content of α-Al2O3 and MgO in the carrier within the aforementioned range is conducive to significantly improving the conversion rate of the hydrogenation reaction while maintaining a high OPP selectivity.

[0052] The active component in the hydrogenation catalyst of the present invention or its precursor is mainly a precious metal represented by platinum. In the present invention, the active component has the conventional meaning in the art and is a substance that plays a catalytic role in the catalyst. In some embodiments, the active component is platinum. In the present invention, platinum as an active component can exist in the form of a soluble platinum-containing compound, platinum oxide and / or metallic platinum. The hydrogenation catalyst of the present invention is obtained by calcining and optionally further reducing (also known as activation) a carrier (i.e., a hydrogenation catalyst precursor) loaded with a soluble platinum-containing compound. Therefore, the active component platinum in the hydrogenation catalyst precursor is usually present in the form of a soluble platinum-containing compound, the active component platinum in the unreduced hydrogenation catalyst is usually present in the form of platinum oxide, and the active component platinum in the reduced hydrogenation catalyst is usually present in the form of metallic platinum or a mixture of metallic platinum and platinum oxide, wherein the ratio of metallic platinum to platinum oxide is related to the degree of reduction.

[0053] A feature of the present invention is that the amount of active components (such as platinum) in the catalyst can be greatly reduced while ensuring good conversion and OPP selectivity. In the hydrogenation catalyst of the present invention or its precursor, the mass of the platinum element can be no more than 1%, 0.7%, 0.6%, 0.5%, 0.3%, or even 0.2% of the mass of the carrier. Herein, the mass ratio of the platinum element to the carrier is also referred to as the Pt loading. In some embodiments, the mass of the platinum element is 0.1% to 1% of the mass of the carrier, preferably 0.1% to 0.7%, more preferably 0.1% to 0.6%, for example 0.2±0.05%, 0.3±0.05%, 0.5±0.05%, 0.6±0.05% or in the range composed of any two of these contents.

[0054] In some preferred embodiments, in the hydrogenation catalyst of the present invention or its precursor, the mass of α-Al2O3 accounts for 76% to 84% of the total mass of the carrier, the mass of MgO accounts for 16% to 24% of the total mass of the carrier, and the mass of the platinum element is 0.5±0.1% or 0.5±0.05% of the mass of the carrier.

[0055] In some preferred embodiments, the hydrogenation catalyst of the present invention or its precursor comprises α-Al2O3, MgO and one selected from a soluble platinum-containing compound, platinum oxide, metallic platinum, and a mixture of metallic platinum and platinum oxide, or is composed of α-Al2O3, MgO and one selected from a soluble platinum-containing compound, platinum oxide, metallic platinum, and a mixture of metallic platinum and platinum oxide; preferably, in the hydrogenation catalyst or its precursor, the mass of α-Al2O3 accounts for 76%-84% of the total mass of the carrier, the mass of MgO accounts for 16%-24% of the total mass of the carrier, and the mass of the platinum element is 0.5±0.1% or 0.5±0.05% of the mass of the carrier.

[0056] The hydrogenation catalyst precursor of the present invention can be prepared by a method comprising the following steps:

[0057] (1) loading a soluble magnesium-containing compound on the surface of α-Al2O3 and calcining to obtain the carrier;

[0058] (2) Loading a soluble platinum-containing compound on the surface of the carrier to obtain the hydrogenation catalyst precursor.

[0059] The soluble magnesium-containing compound suitable for the present invention can be a soluble magnesium salt, such as one or more of magnesium nitrate, magnesium acetate and magnesium chloride. The soluble magnesium-containing compound can be loaded on the surface of α-Al2O3 by preparing an aqueous solution of the soluble magnesium-containing compound and contacting α-Al2O3 with the aqueous solution of the soluble magnesium-containing compound. The concentration of the aqueous solution of the soluble magnesium-containing compound (such as an aqueous solution of magnesium nitrate) can be 20-40wt%, such as 32±2wt%. α-Al2O3 can be contacted with the aqueous solution of the soluble magnesium-containing compound by spraying or dipping. Spraying or dipping can be carried out under heating (such as 20-70°C) to promote the adsorption of α-Al2O3 on the aqueous solution of the magnesium-containing compound and to allow a certain degree of drying to occur during the contact process. For example, spraying can be accompanied by blast drying, and the blast temperature can be 20-70°C, such as 50±10°C. The purpose of the blast is to make the material dry to a certain extent while loading, so that α-Al2O3 can better adsorb the magnesium compound aqueous solution. After loading by immersion, it can be stirred and evaporated at 80±20°C. In some embodiments, the loading operation (e.g., spraying and blast drying) of step (1) is carried out in a sugar coater, a coating machine, a ball rolling machine or a rotary mixer. The speed of the sugar coater, coating machine, ball rolling machine or rotary mixer is preferably 5 to 40 rpm. Using a sugar coater, a coating machine, a ball rolling machine or a rotary mixer for loading is beneficial to industrial amplification. Setting the speed to 5 to 40 rpm is beneficial to ensure that the material can tumble in the machine, achieve the purpose of fully uniform loading, and avoid excessive wear of the material.

[0060] After the soluble magnesium-containing compound is loaded on the surface of α-Al2O3, it can be dried first and then calcined to obtain a carrier. The α-Al2O3 loaded with the soluble magnesium-containing compound can be dried at 60 to 120°C, such as 100±10°C, for 5 to 16 hours, such as 5 to 6 hours.

[0061] In the present invention, the method of calcining α-Al2O3 loaded with soluble magnesium-containing compounds is: heating from room temperature to 500-700°C, for example, 600±5°C, at a heating rate of 3-10°C / min, for example, 5±1°C / min, and then roasting at the raised temperature for 2-8h, for example, 5±1h. The present invention controls the heating rate at 3-10°C / min, which can prevent the loaded components from evaporating or decomposing too quickly during the roasting process, affecting the uniformity of the final load; at the same time, it avoids increasing the roasting time and energy consumption due to too slow heating. The present invention controls the roasting constant temperature at 500-700°C and the time at 2-8h, which can ensure that the loaded components can be fully decomposed in the shortest time with minimum energy consumption.

[0062] In the present invention, when preparing the carrier, the operation of step (1) can be performed only once or repeatedly, that is, MgO can be coated on the surface of α-Al2O3 at one time or in batches. In some embodiments, the operation of step (1) is performed twice, that is, a part (e.g., half) of the soluble magnesium-containing compound is first loaded on the surface of α-Al2O3, calcined to obtain an intermediate carrier, and then the remaining soluble magnesium-containing compound is loaded on the surface of the intermediate carrier, calcined, thereby obtaining the final carrier. The preparation of the carrier by repeating step (1) multiple times is suitable for the preparation of a carrier with a higher MgO loading, which is conducive to the uniform coating of MgO on the surface of α-Al2O3, and improves the conversion rate and OPP selectivity of the hydrogenation reaction.

[0063] The soluble platinum-containing compound suitable for the present invention can be one or more selected from chloroplatinic acid, tetraammine platinum nitrate and tetraammine platinum chloride. The soluble platinum-containing compound can be prepared into an aqueous solution, and the carrier can be contacted with the aqueous solution of the soluble platinum-containing compound to load the soluble platinum-containing compound on the surface of the carrier. The Pt ion concentration of the aqueous solution of the soluble platinum-containing compound (such as chloroplatinic acid aqueous solution) can be 0.5-2wt%, such as 1±0.2wt%. The carrier can be contacted with the aqueous solution of the soluble platinum-containing compound by spraying or dipping. Spraying or dipping can be carried out under heating (such as 20-70°C) to promote the adsorption of the carrier to the aqueous solution of the platinum-containing compound and to allow a certain degree of drying to occur during the contact process. For example, spraying can be accompanied by blast drying, and the blast temperature can be 20-70°C, such as 50±10°C. Blast is mainly to make the material dry to a certain extent while loading, so that the carrier can better adsorb the aqueous solution of the platinum-containing compound. After loading by dipping, it can be stirred and evaporated at 80±20°C. In some embodiments, the loading operation (e.g., spraying and air drying) of step (2) is performed in a sugar coater, a coating machine, a ball rolling machine, or a rotary mixer. The rotation speed of the sugar coater, the coating machine, the ball rolling machine, or the rotary mixer is preferably 5 to 40 rpm. Using a sugar coater, a coating machine, a ball rolling machine, or a rotary mixer for loading is beneficial for industrial amplification. Setting the rotation speed to 5 to 40 rpm is beneficial to ensure that the material can be tumbled in the machine to achieve the purpose of fully uniform loading, while avoiding excessively fast material wear.

[0064] After the soluble platinum-containing compound is loaded on the surface of the carrier, it can be dried to obtain a hydrogenation catalyst precursor. The carrier can be dried at 60 to 120° C., such as 80±10° C., for 5 to 16 hours, such as 12±2 hours.

[0065] The hydrogenation catalyst of the present invention can be prepared by calcining a hydrogenation catalyst precursor. In the present invention, the hydrogenation catalyst precursor is calcined by heating the temperature from room temperature to 500-700°C, for example, 600±50°C, at a heating rate of 3-10°C / min, for example, 5±1°C / min, and then roasting at the raised temperature for 2-8h, for example, 2-3h. The present invention controls the heating rate at 3-10°C / min, which can prevent the loaded components from evaporating or decomposing too quickly during the roasting process, affecting the uniformity of the final load; at the same time, it avoids increasing the roasting time and energy consumption due to too slow heating. The present invention controls the roasting constant temperature at 500-700°C and the time at 2-8h, which can ensure that the loaded components can be fully decomposed in the shortest time with minimum energy consumption.

[0066] The catalyst obtained after calcining the hydrogenation catalyst precursor is an inactivated catalyst. An activated catalyst can be obtained by reducing the inactivated catalyst. In the present invention, the activation of the hydrogenation catalyst can be achieved by reacting the hydrogenation catalyst with a reducing agent at a certain temperature. The reducing agent can be a reducing atmosphere such as hydrogen. The temperature of the reduction reaction can be 350 to 450°C, for example, 400±20°C. The time of the reduction reaction can be 2 to 6h, for example, 4±1h. The rate of rising from room temperature to the reduction reaction temperature during the reduction reaction can be 3 to 10°C / min, for example, 5±1°C / min.

[0067] The hydrogenation catalyst of the present invention is suitable for catalytic hydrogenation reaction, and is particularly suitable for catalytic hydrogenation of dibenzofuran to prepare o-phenylphenol. The hydrogenation catalyst of the present invention can improve the conversion rate and / or selectivity of the hydrogenation reaction. The present invention also includes a method for preparing o-phenylphenol by catalytic hydrogenation of dibenzofuran using the hydrogenation catalyst of the present invention, the method comprising subjecting dibenzofuran to hydrogenation reaction in the presence of the hydrogenation catalyst of the present invention. If the hydrogenation catalyst used for the hydrogenation reaction is an unactivated hydrogenation catalyst, the catalyst is first subjected to the aforementioned activation treatment before the hydrogenation reaction. The hydrogenation reaction can be carried out in a fixed bed reactor. In the hydrogenation reaction, the dibenzofuran raw material can be provided in the form of a dibenzofuran solution or a molten dibenzofuran. The solvent of the dibenzofuran solution can be toluene, methylcyclohexane or a mixture thereof. The dibenzofuran concentration of the dibenzofuran solution is preferably ≥20wt%. The reaction temperature of the hydrogenation reaction can be 350 to 450°C, for example 400±20°C. During the hydrogenation reaction, hydrogen is introduced, and the hydrogen pressure can be 0.3-5 MPa, such as 0.5-1.5 MPa, 1.1±0.1 MPa. During the hydrogenation reaction, the mass space velocity (WHSV) of dibenzofuran is 0.5-1.5 h -1 , for example 0.8±0.1h -1 . The mass space velocity of dibenzofuran is equal to the mass flow rate of dibenzofuran / the mass of the catalyst. When dibenzofuran is fed in the form of a dibenzofuran solution, the mass space velocity of the dibenzofuran is not included in the calculation of the mass space velocity of the dibenzofuran. The hydrogen-to-oil ratio of the hydrogenation reaction can be (600-3000):1, for example (1000±200):1. The hydrogen-to-oil ratio is the ratio of the volume of the hydrogen introduced to the volume of the dibenzofuran raw material.

[0068] By using the hydrogenation catalyst of the present invention to catalyze the dibenzofuran hydrogenation reaction, the dibenzofuran conversion rate can reach more than 30%, more than 33%, more than 34%, more than 35%, more than 36%, more than 38%, more than 39%, more than 40%, more than 41%, more than 42% or more than 45%, and the OPP selectivity can reach more than 80%, more than 81%, more than 83%, more than 84%, more than 85%, more than 86% or more than 87%. In a preferred embodiment, the dibenzofuran conversion rate is more than 38%, and the OPP selectivity is more than 80%.

[0069] The present invention has the following advantages:

[0070] 1. In order to utilize the activity of the carrier itself and carry more active metals, active materials with high specific area are usually used as carriers of supported catalysts in this field. For example, when Al2O3 is used as a carrier of supported catalysts, γ-Al2O3, θ-Al2O3, mesoporous Al2O3, etc. with certain activity and high specific surface area are usually selected. The existing technologies such as CN104841421A, CN105879862A, and CN108947775A are based on the above considerations in the selection of carriers. The present invention proposes a new idea for designing catalyst carriers. The composite carrier of the present invention adopts molded inert α-Al2O3 (commonly known as corundum), which has the characteristics of high strength, good stability, inertness, and low specific surface area. The MgO / α-Al2O3 composite oxide carrier used in the present invention has the characteristics of alkalinity and low specific surface area, which is conducive to the active metal being dispersed more on the outer surface of the carrier and reducing the amount of precious metal used; it is conducive to the diffusion of reaction products and improves OPP selectivity; the alkalinity of the catalyst is also conducive to reducing the generation of by-products and improving OPP selectivity.

[0071] 2. The present invention can prepare the composite carrier and load the active component Pt by spraying or impregnation, which is conducive to uniform dispersion of magnesium oxide on α-Al2O3 and Pt on the surface of the composite carrier.

[0072] 3. The method of the present invention uses less precious metal Pt in the catalyst prepared, which is beneficial to reducing the cost of the catalyst.

[0073] 4. The catalyst prepared by the method of the present invention has an OPP selectivity greater than 80% and an OPP yield greater than 30% when catalyzing the hydrogenation of dibenzofuran to prepare OPP, a small proportion of by-products, a long catalyst service life, and a long reaction activity stability period.

[0074] 5. The preparation method of the present invention is simple, the raw materials are easily available, the cost is low, and it is conducive to large-scale industrial production.

[0075] CN104841421A uses an equal volume impregnation method to combine active metals Pt and Pd with carriers such as γ-Al2O3, θ-Al2O3, SiO2 or activated carbon to prepare a catalyst, which requires a high mass fraction of active precious metal loading to achieve high selectivity for OPP, and the catalyst cost is high, which limits its application in actual industry. The present invention uses alumina of a specific crystal form (α-type) as the carrier core, and the surface is coated with alkaline oxides to form an alkaline composite carrier with a lower specific surface area, which improves the selectivity for OPP and has fewer by-products, thereby greatly reducing the cost of subsequent separation, while reducing the Pt loading and reducing the catalyst cost.

[0076] CN105879862A adds a carrier to a platinum metal salt solution, wherein a noble metal platinum precursor and an inducer are dissolved in a polyol and aged for more than 30 days, and the carrier is obtained by a method of ammonia / water vapor co-induced hydrolysis, and then a rapid reduction reaction is performed to control the viscosity of the solution and the deposition of platinum nanoparticles on the surface of the carrier, and a stable eggshell-type platinum catalyst is formed by filtering, washing, and heating and drying in an inert atmosphere. This method is complex in process, time-consuming to prepare, and is not conducive to industrial production.

[0077] CN106478378A uses a fixed bed reactor to prepare OPP by hydrogenating a precious metal catalyst, but its conversion rate is low, resulting in a low OPP yield and unclear economic benefits.

[0078] Compared with the existing catalyst for preparing OPP by hydrogenation of dibenzofuran, the present invention has the advantages of simple catalyst preparation process, low active metal loading, low catalyst cost, high OPP selectivity, few by-products, good stability and long service life. The method of the present invention does not need to use strong acid, strong base and the like for carrier treatment, nor does it need to use a large amount of water or organic solvent for washing, thus avoiding equipment corrosion and being environmentally friendly. The method of the present invention can be industrialized and mass-produced, and has good application prospects in the industrial field of preparing OPP by hydrogenation of dibenzofuran.

[0079] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the preparation examples can all be purchased through commercial routes.

[0080] The α-Al2O3 used in the embodiments and comparative examples was produced in Jiangxi with a purity of 99%; the γ-Al2O3 was purchased from Shanghai Test with a purity of 99%; the SiO2 (white carbon black) was purchased from Wokai; and the θ-Al2O3 was produced in Shandong with a purity of 99%.

[0081] Example 1

[0082] Take 100g of strip α-Al2O3 with a diameter of 3mm and put it into a sugar coating machine with a rotation speed of 30r / min. Slowly spray 100g of magnesium nitrate aqueous solution with a mass fraction of 32% of magnesium nitrate onto the surface of the carrier. During the whole spraying process, the air blast of the sugar coating machine is turned on and the wind temperature is maintained at 50°C. After the spraying of the magnesium nitrate solution is completed, take out the carrier and dry it at 100°C for 5h. Put the dried sample into a muffle furnace for roasting, heating it from room temperature to 600°C at a heating rate of 5°C / min, and then roast it at 600°C for 5 hours to obtain a MgO-Al2O3 composite carrier, in which the MgO content is about 8wt% and the α-Al2O3 content is about 92wt%.

[0083] Take 100g of the above composite carrier and put it into a sugar coating machine with a speed of 25r / min. Slowly spray 50g of a chloroplatinic acid aqueous solution with a Pt mass fraction of 1% onto the surface of the carrier. During the entire spraying process, the sugar coating machine is turned on and the wind temperature is maintained at 50°C. After the spraying of the chloroplatinic acid solution is completed, take out the sample and dry it at 80°C for 12h. The dried sample is placed in a muffle furnace for calcination, and the temperature is increased from room temperature to 600°C at a heating rate of 5°C / min, and then calcined at 600°C for 2 hours to obtain a catalyst with a Pt loading of 0.5wt%.

[0084] Example 2

[0085] The amount of the magnesium nitrate aqueous solution with a mass fraction of 32% of magnesium nitrate in Example 1 was changed to 220 g, and the rest of the preparation method was the same as that in Example 1 to prepare the catalyst of Example 2. The MgO content in the carrier of the catalyst was about 16 wt%, the α-Al2O3 content was about 84 wt%, and the Pt loading in the catalyst was 0.5 wt%.

[0086] Example 3

[0087] The amount of the magnesium nitrate aqueous solution with a mass fraction of 32% of magnesium nitrate in Example 1 was changed to 61 g, and the rest of the preparation method was the same as that in Example 1 to prepare the catalyst of Example 3. The MgO content in the carrier of the catalyst was about 5wt%, the α-Al2O3 content was about 95wt%, and the Pt loading in the catalyst was 0.5wt%.

[0088] Example 4

[0089] Take 100g of α-Al2O3 strips with a diameter of 3mm and put them into a sugar coating machine. The speed of the sugar coating machine is 30r / min. Slowly spray 110g of magnesium nitrate aqueous solution with a mass fraction of 32% magnesium nitrate onto the surface of the carrier. During the whole spraying process, the sugar coating machine is turned on and the wind temperature is maintained at 50°C. After the magnesium nitrate solution is sprayed, take out the carrier and dry it at 100°C for 5h. Put the dried sample into a muffle furnace for roasting, and heat it from room temperature to 600°C at a heating rate of 5°C / min. Then roast it at 600°C for 5 hours, take out the carrier, put the carrier into the sugar coating machine, and coat it. The machine speed is 30r / min, and 110g of magnesium nitrate aqueous solution with a mass fraction of 32% of magnesium nitrate is sprayed onto the carrier again. During the whole spraying process, the sugar coating machine is turned on and the wind temperature is maintained at 50°C. After the spraying of the magnesium nitrate solution is completed, the carrier is taken out and dried at 100°C for 5h. The dried sample is placed in a muffle furnace for roasting, and the temperature is increased from room temperature to 600°C at a heating rate of 5°C / min, and then roasted at 600°C for 5 hours to obtain a MgO-Al2O3 composite carrier, in which the MgO content is about 16wt%, and the α-Al2O3 content is about 84wt%.

[0090] Take 100g of the above composite carrier and put it into a sugar coating machine. The speed of the sugar coating machine is 25r / min. Slowly spray 50g of chloroplatinic acid aqueous solution with a Pt mass fraction of 1% onto the surface of the carrier. During the entire spraying process, the sugar coating machine is turned on and the wind temperature is maintained at 50°C. After the spraying of the chloroplatinic acid solution is completed, take out the carrier and dry it at 80°C for 12h. Put the dried sample into a muffle furnace for roasting, and heat it from room temperature to 600°C at a heating rate of 5°C / min, and then roast it at 600°C for 2 hours to obtain a catalyst with a Pt loading of 0.5wt%. The XRD spectrum of the catalyst of Example 4 is shown as follows: Figure 1 As shown, the Pt peak cannot be seen due to the low Pt content and high dispersion of the catalyst.

[0091] Example 5

[0092] The amount of the magnesium nitrate aqueous solution with a magnesium nitrate mass fraction of 32% in Example 4 was changed from 110 g to 150 g, and the rest of the preparation method was the same as that in Example 4 to prepare the catalyst of Example 5. The MgO content in the carrier of the catalyst was about 20 wt%, the α-Al2O3 content was about 80 wt%, and the Pt loading in the catalyst was 0.5 wt%.

[0093] Example 6

[0094] The amount of the magnesium nitrate aqueous solution with a magnesium nitrate mass fraction of 32% in Example 4 was changed from 110 g to 183 g, and the rest of the preparation method was the same as that in Example 4 to prepare the catalyst of Example 6. The MgO content in the carrier of the catalyst was about 24 wt%, the α-Al2O3 content was about 76 wt%, and the Pt loading in the catalyst was 0.5 wt%.

[0095] Example 7

[0096] The amount of the chloroplatinic acid aqueous solution with a Pt mass fraction of 1% in Example 4 was changed to 20 g, and the rest of the preparation method was the same as that in Example 4 to prepare the catalyst of Example 7. The MgO content in the carrier of the catalyst was about 16 wt%, the α-Al2O3 content was about 84 wt%, and the Pt loading in the catalyst was 0.2 wt%.

[0097] Example 8

[0098] The amount of chloroplatinic acid aqueous solution with a Pt mass fraction of 1% in Example 4 was changed to 60 g, and the rest of the preparation method was the same as that in Example 4 to prepare the catalyst of Example 8. The MgO content in the carrier of the catalyst was about 16 wt%, the α-Al2O3 content was about 84 wt%, and the Pt loading in the catalyst was 0.6 wt%.

[0099] Example 9

[0100] The amount of the chloroplatinic acid aqueous solution with a Pt mass fraction of 1% in Example 4 was changed to 30 g, and the rest of the preparation method was the same as that in Example 4 to prepare the catalyst of Example 9. The MgO content in the carrier of the catalyst was about 16 wt%, the α-Al2O3 content was about 84 wt%, and the Pt loading in the catalyst was 0.3 wt%.

[0101] Example 10

[0102] The α-Al2O3 in Example 2 is changed to strip-shaped α-Al2O3 with a diameter of 4 mm. The rest of the preparation method is the same as that of Example 2, and the catalyst of Example 10 is prepared.

[0103] Embodiment 11

[0104] The α-Al2O3 in Example 2 is changed to spherical α-Al2O3 with a diameter of 3 mm. The rest of the preparation method is the same as that of Example 2, and the catalyst of Example 11 is prepared.

[0105] Example 12

[0106] The α-Al2O3 in Example 2 is changed to a hollow α-Al2O3 with an outer diameter of 4 mm and an inner diameter of 1 mm. The rest of the preparation method is the same as that of Example 2, and the catalyst of Example 12 is prepared.

[0107] Embodiment 13

[0108] Take 100g of strip α-Al2O3 with a diameter of 3mm, put it into 110g of magnesium nitrate aqueous solution with a mass fraction of 32% magnesium nitrate, immerse it for 2h, stir and evaporate it at 80℃, and then dry it in an oven at 100℃ for 5h, put the dried sample into a muffle furnace for roasting, heat it from room temperature to 600℃ at a heating rate of 5℃ / min, and then roast it at 600℃ for 5 hours. Then put it into 110g of magnesium nitrate aqueous solution with a mass fraction of 32% magnesium nitrate again for immersion for 2h, stir and evaporate it at 80℃, and then dry it in an oven at 100℃ for 5h, put the dried sample into a muffle furnace for roasting, heat it from room temperature to 600℃ at a heating rate of 5℃ / min, and then roast it at 600℃ for 5 hours to obtain a MgO-Al2O3 composite carrier. The MgO content in the obtained composite carrier is about 16wt%, and the α-Al2O3 content is about 84%.

[0109] Take 100g of the composite carrier, put it into 50g of chloroplatinic acid aqueous solution with a Pt mass fraction of 1%, immerse it for 5h, dry it in an oven at 80℃ for 12h, and finally calcine it in a muffle furnace, heating it from room temperature to 600℃ at a heating rate of 5℃ / min, and then calcine it at 600℃ for 2h to obtain a catalyst with a Pt loading of about 0.5wt%.

[0110] Comparative Example 1

[0111] The α-Al2O3 in Example 2 was replaced by γ-Al2O3 strips with a diameter of 3 mm, and the rest of the preparation method was the same as that in Example 2 to obtain the catalyst of Comparative Example 1. The MgO content in the carrier of the catalyst was about 16wt%, the γ-Al2O3 content was about 84%, and the Pt loading in the catalyst was about 0.5wt%.

[0112] Comparative Example 2

[0113] The α-Al2O3 in Example 2 was replaced with SiO2 strips with a diameter of 3 mm, and the rest of the preparation method was the same as that in Example 2 to obtain the catalyst of Comparative Example 2. The MgO content in the carrier of the catalyst was about 16wt%, the SiO2 content was about 84%, and the Pt loading in the catalyst was about 0.5wt%.

[0114] Comparative Example 3

[0115] The α-Al2O3 in Example 2 was replaced by spherical θ-Al2O3 with a diameter of 3 mm, and the rest of the preparation method was the same as that in Example 2 to obtain the catalyst of Comparative Example 3. The MgO content in the carrier of the catalyst was about 16wt%, the θ-Al2O3 content was about 84%, and the Pt loading in the catalyst was about 0.5wt%.

[0116] Comparative Example 4

[0117] Take 100g of strip α-Al2O3 with a diameter of 3mm and put it into a sugar coating machine. The speed of the sugar coating machine is 30r / min. Slowly spray 50g of chloroplatinic acid aqueous solution with a Pt mass fraction of 1% onto the surface of α-Al2O3. During the whole spraying process, the air blowing of the sugar coating machine is turned on and the wind temperature is maintained at 50°C. After the spraying of the chloroplatinic acid solution is completed, take out the sample, dry it at 80°C for 12h, put the dried sample into a muffle furnace for calcination, and heat it from room temperature to 600°C at a heating rate of 5°C / min, and then calcine it at 600°C for 2 hours to obtain a catalyst with a Pt loading of about 0.5wt%.

[0118] Test Example 1: Catalyst Evaluation

[0119] 5 g of catalyst was placed in a fixed bed constant temperature zone, hydrogen was introduced, and the catalyst was heated to 400°C at a rate of 5°C / min and kept at 400°C for 4 hours for activation; then a 20 wt% toluene solution of dibenzofuran was introduced, and the mass space velocity (WHSV) of the reaction raw material dibenzofuran was 0.8 h -1 , hydrogen-to-oil ratio of 1000:1, hydrogen pressure of 1.1 MPa, reaction temperature of 400°C; gas chromatography analysis was used to calculate the conversion rate of dibenzofuran and OPP selectivity based on the reaction results of the catalyst in a steady state after the catalyst was operated for 200 hours. The catalyst evaluation results of each embodiment and comparative example are shown in Table 1.

[0120] Table 1: Catalyst compositions and reaction results of various embodiments and comparative examples

[0121]

[0122]

[0123] Fresh supported hydrogenation catalysts usually have very high initial activity in the initial stage of the reaction (several hours to tens of hours) due to the influence of factors such as the very small initial particle size of the active component, high degree of dispersion, and few surface adsorbed impurities, but the reaction result is unstable and the conversion rate will decrease rapidly. After the reaction runs for a period of time or after the passivation treatment is actively implemented, the catalyst will enter the active stable period, that is, a relatively stable conversion rate and selectivity will be achieved. In industrial applications, the reaction data after the active stable period or long-term operation are used to calculate the product yield, energy consumption cost, etc. Therefore, the test examples of the present invention all use the reaction results of the catalyst running for about 200h and being in the active stable period to calculate the conversion rate and selectivity of the catalyst.

[0124] According to the reaction results of the catalysts of Examples 1-13 and Comparative Examples 1-3, it can be seen that under the action of the catalyst of the examples with MgO coated α-Al2O3 as a composite carrier, the reaction of hydrogenation and hydrogenolysis of benzophenone to prepare OPP maintains a relatively high conversion rate while the OPP selectivity is greatly improved compared with the catalyst of the comparative examples with MgO coated γ-Al2O3, SiO2 or θ-Al2O3 as a composite carrier.

[0125] According to the reaction results of the catalysts of Examples 1-13 and Comparative Example 4, it can be seen that compared with the catalyst of Comparative Example 4 with pure α-Al2O3 as the carrier, the catalyst of the embodiment with MgO-coated α-Al2O3 as the composite carrier catalyzed the hydrogenation and hydrogenolysis reaction of benzophenone. The conversion rate is significantly improved, and the OPP selectivity is maintained at a very high level.

[0126] Test Example 2: Catalyst Stability Evaluation

[0127] 5 g of the catalyst of Example 4 was placed in a fixed bed constant temperature zone, hydrogen was introduced into the catalyst, the temperature was raised to 400° C. at 5° C. / min, and it was retained for 4 hours for activation, and then a 20 wt % toluene solution of dibenzofuran was introduced, and the mass space velocity (WHSV) of the reaction raw material dibenzofuran was 0.8 h -1 , the hydrogen-to-oil ratio was 1000:1, the hydrogen pressure was 1.1 MPa, and the reaction temperature was 400°C; gas chromatography analysis was used to calculate the dibenzofuran conversion rate and OPP selectivity at different operating times based on the reaction results when the catalyst was running at different operating times. The results are shown in Table 2.

[0128] Table 2: Stability test results of the catalyst of Example 4

[0129] Running time (h) Dibenzofuran conversion rate (%) OPP selectivity (%) 20 67 71 50 55 75 100 49 80 150 44 83 200 42 85 300 43 85 500 42 85 700 41 86 900 41 86 1100 40 87 1300 41 86 1500 40 87

[0130] It can be seen from the data in Table 2 that the catalyst prepared by the method of the present invention can maintain a high selectivity for OPP during long-term operation; after continuous operation for 1500 hours, the activity still remains at the level of the activity stable period and does not decrease, indicating that the catalyst has good stability and a long catalyst service life.

Claims

1. A hydrogenation catalyst for preparing o-phenylphenol by hydrogenation of dibenzofuran, characterized in that: The hydrogenation catalyst comprises a carrier and an active component having a catalytic effect, wherein the carrier comprises α-Al2O3 and MgO, and the active component is a platinum element; in the carrier, the mass of α-Al2O3 accounts for 70% to 96% of the total mass of the carrier, and the mass of MgO accounts for 4% to 30% of the total mass of the carrier; in the hydrogenation catalyst, the mass of the platinum element accounts for 0.1% to 1% of the mass of the carrier.

2. The hydrogenation catalyst according to claim 1, characterized in that In the carrier, the mass of α-Al2O3 accounts for 76% to 95% of the total mass of the carrier, and the mass of MgO accounts for 5% to 24% of the total mass of the carrier.

3. The hydrogenation catalyst according to claim 1, characterized in that In the hydrogenation catalyst, the mass of the platinum element is 0.1% to 0.7% of the mass of the carrier.

4. The hydrogenation catalyst according to claim 1, characterized in that In the hydrogenation catalyst, the mass of the platinum element is 0.1% to 0.6% of the mass of the carrier.

5. The hydrogenation catalyst according to claim 1, characterized in that The hydrogenation catalyst has one or more of the following characteristics: The MgO is located on the surface of the α-Al2O3; The α-Al2O3 is a particle with a particle size of 2 to 5 mm; and The platinum element exists in the form of a soluble platinum-containing compound, platinum oxide and / or metallic platinum.

6. A method for preparing the hydrogenation catalyst according to any one of claims 1 to 5, characterized in that: The method comprises the following steps: (1) loading a soluble magnesium-containing compound on the surface of α-Al2O3 and calcining to obtain the carrier; (2) Loading a soluble platinum-containing compound on the surface of the carrier to obtain a hydrogenation catalyst precursor.

7. The method according to claim 6, characterized in that The method has one or more of the following features: The soluble magnesium-containing compound is selected from one or more of magnesium nitrate, magnesium acetate and magnesium chloride; In step (1), the loading is performed using a sugar coating machine, a coating machine, a ball rolling machine or a rotary mixer; In step (1), a soluble magnesium-containing compound is loaded on the surface of α-Al2O3 by spraying or dipping; The calcination method in step (1) is: heating from room temperature to 500-700°C at a heating rate of 3-10°C / min, and then calcining for 2-8h; In step (1), before calcination, the α-Al2O3 loaded with the soluble magnesium-containing compound is dried; The soluble platinum-containing compound is selected from one or more of chloroplatinic acid, tetraamineplatinum nitrate and tetraamineplatinum chloride; In step (2), the loading is performed using a sugar coating machine, a coating machine, a ball rolling machine or a rotary mixer; In step (2), a soluble platinum-containing compound is loaded on the surface of the carrier by spraying or dipping; Step (2) further comprises drying the carrier loaded with the soluble platinum-containing compound.

8. The method according to claim 6, characterized in that In step (1), the loading is performed using a sugar coater, a coating machine, a ball rolling machine or a rotary mixer, and the rotation speed of the sugar coater, the coating machine, the ball rolling machine or the rotary mixer is 5 to 40 rpm.

9. The method according to claim 6, characterized in that In step (1), before calcination, the α-Al2O3 loaded with the soluble magnesium-containing compound is dried at 60-120°C for 5-16 hours.

10. The method according to claim 6, characterized in that In step (2), the loading is performed using a sugar coater, a coating machine, a ball rolling machine or a rotary mixer, and the rotation speed of the sugar coater, the coating machine, the ball rolling machine or the rotary mixer is 5 to 40 rpm.

11. The method according to claim 6, characterized in that Step (2) further comprises drying the carrier loaded with the soluble platinum-containing compound, wherein the drying is performed at 60-120° C. for 5-16 hours.

12. The method according to claim 6, characterized in that The method further comprises the following steps: (3) calcining the hydrogenation catalyst precursor to obtain the hydrogenation catalyst.

13. The method according to claim 12, characterized in that The calcination method in step (3) is: heating from room temperature to 500-700°C at a heating rate of 3-10°C / min, and then calcining for 2-8h.

14. The method according to claim 12, characterized in that The method further comprises the following steps: (4) Reducing the hydrogenation catalyst obtained in step (3) at 350-450° C. for 2-6 h.

15. A method for catalytic hydrogenation reaction, characterized in that: The method comprises using the hydrogenation catalyst described in any one of claims 1 to 5 to catalyze a hydrogenation reaction, wherein the hydrogenation reaction is a reaction of hydrogenating dibenzofuran to prepare o-phenylphenol.

16. The method according to claim 15, characterized in that The method has one or more of the following features: The hydrogenation reaction is carried out in a fixed bed reactor; In the hydrogenation reaction, the dibenzofuran raw material is provided in the form of a dibenzofuran solution or a molten dibenzofuran; In the hydrogenation reaction, the reaction temperature is 350-450°C; In the hydrogenation reaction, the hydrogen pressure is 0.3~5MPa; In the hydrogenation reaction, the mass space velocity of dibenzofuran is 0.5~1.5h -1 ; In the hydrogenation reaction, the hydrogen-to-oil ratio is (600-3000):

1.

17. The method according to claim 16, characterized in that The solvent of the dibenzofuran solution is toluene, methylcyclohexane or a mixture thereof.

18. The method according to claim 16, characterized in that The dibenzofuran concentration of the dibenzofuran solution is ≥20wt%.

19. Use of the hydrogenation catalyst according to any one of claims 1 to 5 in improving the selectivity and / or stability of o-phenylphenol in the reaction of preparing o-phenylphenol by hydrogenating dibenzofuran.

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