A catalyst for the hydrogenation of aryl formates, its preparation and use

Abstract

The present disclosure relates to an aromatic formate hydrogenation catalyst and a preparation method and application thereof, which comprises the following steps: S1, mixing a metal source, an alkali source and water to obtain a catalyst precursor; S2, heat treating the catalyst precursor to obtain a pre-product; S3, contacting the pre-product with a hydrogen atmosphere for reduction treatment, and the temperature of the reduction treatment is 450-550 DEG C; the metal source comprises an aluminum source, a copper source and a manganese source; the pH value of the mixture obtained by mixing the metal source, the alkali source and the water is 7.0-11.0; the molar ratio of the aluminum source calculated based on Al2O3, the copper source calculated based on copper element and the manganese source calculated based on manganese element is 1:(0.08-0.20):(0.10-0.22). The catalyst prepared by the above method can perform selective hydrogenation reaction of aromatic formate under mild conditions, and has the advantages of single raw material, simple operation, good catalytic activity and good product selectivity of aromatic methanol.

Description

Technical Field

[0001] The present disclosure relates to the field of chemical technology, and in particular to an aromatic formate hydrogenation catalyst, a preparation method thereof, and applications thereof. Background Art

[0002] Benzyl alcohol is a colorless, transparent liquid with a faint aromatic smell. It is an important intermediate for the synthesis of fragrances and medicines. It is also widely used in the fields of photosensitive materials, cosmetics, coatings, inks, etc. It can be used as a solvent, plasticizer, preservative, and is used in the manufacture of fragrances, soaps, medicines, etc. It is widely used in the production of industrial chemicals.

[0003] Currently, the most common method for producing benzyl alcohol in industry is the benzyl chloride hydrolysis method, which involves azeotropic hydrolysis of benzyl chloride with an aqueous alkali solution. This method is divided into batch hydrolysis and continuous hydrolysis. The batch method involves adding the raw materials, benzyl chloride, water, and soda ash, to a jacketed steel reactor equipped with a reflux condenser. After the raw materials are added, they are heated with continuous stirring, refluxed until CO2 production ceases, and then cooled. Sodium chloride is then added to promote a more distinct separation of the alcohol and water. After separation, industrial-grade benzyl alcohol can be obtained. The crude alcohol is subjected to vacuum distillation, with a yield of 70-72%. The continuous method involves thoroughly mixing the benzyl chloride with an aqueous alkali solution at high temperature (180-275°C) and high pressure (1-6.8 MPa) before entering the hydrolysis zone. This method is time-efficient. The continuous hydrolysis method has the advantage of producing few by-products. The reaction can be carried out in a tower reactor, and the yield of benzyl alcohol is also high, reaching 99%. However, the disadvantages of the continuous method are that it consumes more energy than other methods and poses more serious environmental hazards. The benzyl alcohol obtained by the reaction contains chlorine, which limits its application in food and cosmetics.

[0004] The toluene oxidation method is considered to be the most promising method for producing benzyl alcohol, but there is no industrial report yet. The problem that the toluene oxidation method needs to solve is that the intermediate product benzaldehyde or benzyl alcohol produced by oxidation is easily further oxidized to benzoic acid, and this process is considered to be an auto-oxidation catalytic process. There are also reports on the preparation of benzyl alcohol by hydrogenation of benzaldehyde, but in this method, benzaldehyde is expensive (similar to benzyl alcohol) and is easily oxidized to benzoic acid, which is solid at room temperature, in air, which brings great difficulties to the actual operation process during reaction. There are also some other methods, such as directly or indirectly synthesizing benzyl alcohol with benzene and formaldehyde, electrochemical electrolysis and biological methods to prepare benzyl alcohol. Many of these methods are "green chemistry" synthetic routes, but the disadvantages are complex reactions and many side chain reactions, which limit their application to a certain extent. Therefore, it is of great significance to utilize methyl benzoate one-step selective hydrogenation to generate benzyl alcohol under mild conditions.

[0005] In current literature reports, the selective hydrogenation of methyl benzoate to prepare benzyl alcohol generally uses a homogeneous catalyst, and the composition of the system is complex, which will result in disadvantages such as difficulty in separating the reaction products. Summary of the Invention

[0006] The present invention aims to provide an aromatic formate hydrogenation catalyst, a preparation method and an application thereof. The hydrogenation catalyst can carry out a selective hydrogenation reaction of aromatic formate under mild conditions, and has single raw materials, simple operation, good catalytic activity and good selectivity for aromatic methanol products.

[0007] In order to achieve the above object, the present disclosure provides a first aspect of a method for preparing an aromatic formate hydrogenation catalyst, the method comprising the following steps:

[0008] S1, mixing a metal source, an alkali source and water to react to obtain a catalyst precursor;

[0009] S2, heat-treating the catalyst precursor to obtain a pre-product;

[0010] S3, contacting the pre-product with a hydrogen atmosphere for reduction treatment, wherein the temperature of the reduction treatment is 450-550° C.;

[0011] The metal source includes an aluminum source, a copper source and a manganese source;

[0012] The pH value of the mixture obtained by mixing the metal source, the alkali source and the water is 7.0-11.0;

[0013] The molar ratio of the aluminum source calculated as Al2O3, the copper source calculated as copper element and the manganese source calculated as manganese element is 1:(0.08-0.20):(0.10-0.22).

[0014] Optionally, the aluminum source includes one or more of Al(NO3)3, AlCl3 and Al2(SO4)3;

[0015] The copper source includes one or more of Cu(NO3)2, CuCl2, CuSO4 and Cu(CH3CO2)2;

[0016] The manganese source includes one or more of Mn(NO3)2, MnCl2, MnSO4 and Mn(CH3CO2)2;

[0017] The alkali source includes one or more of alkaline carbonates, alkaline bicarbonates and metal hydroxides, and preferably includes one or more of Na2CO3, NaHCO3, K2CO3, KHCO3, NaOH and KOH.

[0018] Optionally, step S1 includes:

[0019] a. mixing the aqueous solution containing the metal source and the alkali source at 10-80° C. to obtain the mixed material;

[0020] b. Aging the mixture for 2-4 hours at a temperature of 55-65°C.

[0021] Optionally, in step S3, the reduction treatment time is 2-4 hours.

[0022] Optionally, in step S2, the heat treatment method includes calcination, and the calcination conditions include: time of 2-4 hours, temperature of 400-500°C, and the calcination is carried out in an oxygen-containing atmosphere.

[0023] According to a second aspect of the present disclosure, there is provided an aromatic formate hydrogenation catalyst prepared by the method described in the first aspect of the present disclosure.

[0024] A third aspect of the present disclosure provides an aromatic formate hydrogenation catalyst, the aromatic formate hydrogenation catalyst comprising Al2O3, a Cu component, and a Mn component;

[0025] The molar ratio of the Al2O3, the Cu component calculated as copper element, and the Mn component calculated as manganese element is 1: (0.08-0.20): (0.10-0.22);

[0026] An XPS test was performed on the catalyst, and the Cu component on the surface of the catalyst included elemental Cu and Cu2O, and the molar ratio of the elemental Cu to the Cu2O was 1:(0.2-0.8).

[0027] Optionally, the catalyst is subjected to an XPS test, and the Mn component on the surface of the catalyst includes manganese oxide;

[0028] Optionally, an XPS test is performed on the catalyst, and the Mn component on the surface of the catalyst includes MnO and Mn3O4, and the molar ratio of the MnO to the Mn3O4 is 1:(0.3-0.5).

[0029] A fourth aspect of the present disclosure provides a method for hydrogenating an aromatic formate, comprising: subjecting the aromatic formate, a catalyst, and hydrogen to a contact reaction, wherein the catalyst comprises the hydrogenation catalyst described in the second or third aspect of the present disclosure.

[0030] Optionally, the contact reaction conditions include: a temperature of 100-250° C., a hydrogen pressure of 0.5-3.0 MPa;

[0031] Optionally, the contact reaction is carried out in a reactor with a stirring rate of 400-1200 rpm, and the amount of the hydrogenation catalyst is 0.5-1.5 g relative to 1 mL of the aromatic formate; or

[0032] The contact reaction is carried out in a fixed bed reactor, and the mass space velocity of the aromatic formate is 0.1-0.3h -1 .

[0033] Optionally, the aromatic formate has a structure shown in Formula 1:

[0034]

[0035] Ring A is selected from a benzene ring or a C10-C14 fused aromatic ring;

[0036] R1 and R2 are the same or different and are independently selected from C1-C4 alkyl groups;

[0037] n is any integer selected from 0-10;

[0038] Optionally, the contact reaction is carried out in the presence of a solvent, and the solvent includes one or more of n-hexane, n-heptane and cyclohexane.

[0039] Through the above technical solution, the present invention prepares an aromatic formate hydrogenation catalyst containing Al2O3, Cu component and Mn component in specific proportions by co-precipitation, and controls the molar ratio of elemental Cu and Cu2O on the catalyst surface by controlling the conditions of the reduction treatment. The catalyst is used for the selective hydrogenation reaction of aromatic formate, and can be hydrogenated into aromatic methanol in one step under mild conditions. The catalyst has the advantages of a single reactant raw material, a low impurity content of the product, easy product separation, good catalytic activity, and good selectivity for aromatic methanol.

[0040] Other features and advantages of the present disclosure will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0041] The following describes the specific embodiments of the present disclosure in detail. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0042] A first aspect of the present disclosure provides a method for preparing an aromatic formate hydrogenation catalyst, the method comprising the following steps:

[0043] S1, mixing a metal source, an alkali source and water to react to obtain a catalyst precursor;

[0044] S2, heat-treating the catalyst precursor to obtain a pre-product;

[0045] S3, contacting the pre-product with a hydrogen atmosphere for reduction treatment, wherein the temperature of the reduction treatment is 450-550° C.;

[0046] The metal source includes an aluminum source, a copper source and a manganese source;

[0047] The pH value of the mixture obtained by mixing the metal source, the alkali source and the water is 7.0-11.0;

[0048] The molar ratio of the aluminum source calculated as Al2O3, the copper source calculated as copper element and the manganese source calculated as manganese element is 1:(0.08-0.20):(0.10-0.22).

[0049] The present disclosure adopts a co-precipitation method to prepare an aromatic formate hydrogenation catalyst, and controls the pH value of the mixture, so that the components in the prepared catalyst can be evenly distributed. The molar ratio of elemental Cu and Cu2O on the catalyst surface is controlled by controlling the conditions of the reduction treatment, which is beneficial for the hydrogenation of aromatic formate to produce aromatic methanol under mild conditions and improves its catalytic activity and target product selectivity.

[0050] In the present disclosure, pH values ​​are all measured values ​​under the conditions of 25° C. and standard atmospheric pressure.

[0051] According to one embodiment of the present disclosure, the types of aluminum source, copper source and manganese source are conventional in the art. For example, the aluminum source includes a soluble aluminum-containing salt, preferably including one or more of Al(NO3)3, AlCl3 and Al2(SO4)3. When the aluminum source includes more than two types, the present disclosure does not limit their proportion; the copper source includes a copper salt, preferably including one or more of Cu(NO3)2, CuCl2, CuSO4 and Cu(CH3CO2)2. When the copper source includes more than two types, the present disclosure does not limit their proportion; the manganese source includes a soluble manganese salt, preferably including one or more of Mn(NO3)2, MnCl2, MnSO4 and Mn(CH3CO2)2. When the manganese source includes more than two types, the present disclosure does not limit their proportion.

[0052] According to one embodiment of the present disclosure, the alkali source includes one or more of a soluble alkaline carbonate, a soluble alkaline bicarbonate and a soluble metal hydroxide, preferably including one or more of Na2CO3, NaHCO3, K2CO3, KHCO3, NaOH and KOH; when the alkali source includes two or more at the same time, there is no limit on their ratio.

[0053] According to one embodiment of the present disclosure, the molar ratio of the aluminum source calculated as Al2O3, the copper source calculated as copper element, and the manganese source calculated as manganese element is 1:(0.12-0.18):(0.14-0.20).

[0054] According to one embodiment of the present disclosure, step S1 includes:

[0055] a. mixing a metal source with water to obtain an aqueous solution containing the metal source; mixing the aqueous solution containing the metal source with an alkali source at 10-80° C. to obtain a mixed material;

[0056] The alkali source can be mixed with the aqueous solution containing the metal source in the form of an aqueous solution. The aqueous solution containing the metal source and the alkali source can be mixed by adding the aqueous solution containing the alkali source dropwise to the aqueous solution containing the metal source at 10-80° C.; in order to make the coprecipitation reaction more complete, all mixing is carried out under stirring;

[0057] b. Aging the mixture for 2-4 hours at a temperature of 55-65°C;

[0058] c. Cooling the aged mixture and performing solid-liquid separation, washing the solid until the washing liquid is neutral at room temperature, using a conventional solid-liquid separation method in the art, such as vacuum filtration;

[0059] d. Drying the washed solid to obtain a catalyst precursor; the drying time is 10-14 hours at a temperature of 100-120° C., and the drying method is conventional in the art, such as drying in an oven.

[0060] According to one embodiment of the present disclosure, in step S2, the heat treatment method includes calcination, and the calcination conditions include: time is 2-4h, temperature is 400-500°C, and calcination is carried out in an oxygen-containing atmosphere; the oxygen content in the oxygen-containing atmosphere is 20-30% by volume, and the oxygen-containing atmosphere can be, for example, an air atmosphere.

[0061] According to one embodiment of the present disclosure, the reduction treatment time is 2-4 hours.

[0062] According to a second aspect of the present disclosure, there is provided an aromatic formate hydrogenation catalyst prepared by the method described in the first aspect of the present disclosure.

[0063] A third aspect of the present disclosure provides an aromatic formate hydrogenation catalyst, the aromatic formate hydrogenation catalyst comprising Al2O3, a Cu component, and a Mn component;

[0064] The molar ratio of the Al2O3, the Cu component calculated as copper element, and the Mn component calculated as manganese element is 1: (0.08-0.20): (0.10-0.22);

[0065] An XPS test was performed on the catalyst, and the Cu component on the surface of the catalyst included elemental Cu and Cu2O, and the molar ratio of the elemental Cu to the Cu2O was 1:(0.2-0.8).

[0066] The hydrogenation catalyst disclosed herein comprises Al2O3, a Cu component, and a Mn component having a specific composition, and has elemental Cu and Cu2O at a specific molar ratio on the catalyst surface. It is capable of achieving a selective hydrogenation reaction of aromatic formate under mild conditions to produce aromatic methanol in one step. Compared with the manganese-based catalysts of the prior art, it can achieve higher catalytic activity, and compared with the copper-based catalysts of the prior art, it can achieve higher aromatic methanol selectivity.

[0067] According to one embodiment of the present disclosure, a preferred molar ratio of the Al2O3, the Cu component calculated as copper element, and the Mn component calculated as manganese element is 1:(0.12-0.18):(0.14-0.20).

[0068] According to one embodiment of the present disclosure, an XPS test is performed on the catalyst, and the Mn component on the surface of the catalyst includes manganese oxide; further, the manganese oxide includes MnO and Mn3O4.

[0069] According to one embodiment of the present disclosure, XPS analysis of the catalyst revealed a molar ratio of elemental Cu to Cu₂O on the catalyst surface of 1:(0.3-0.5); and a molar ratio of Mn components on the catalyst surface of 1:(0.3-0.5). The components of the hydrogenation catalyst exhibit a synergistic effect, and its use in the hydrogenation of aromatic formates to aromatic methanols can achieve high catalytic activity and aromatic methanol selectivity.

[0070] In the present disclosure, the components and contents on the surface of the catalyst refer to the components and contents within a thickness of 10 nm on the surface of the catalyst as measured by XPS.

[0071] A fourth aspect of the present disclosure provides a method for hydrogenating an aromatic formate, comprising: subjecting the aromatic formate, a catalyst, and hydrogen to a contact reaction, wherein the catalyst comprises the hydrogenation catalyst described in the second or third aspect of the present disclosure.

[0072] According to one embodiment of the present disclosure, the conditions for the contact reaction include: a temperature of 100-250° C., preferably 140-180° C.; and a hydrogen pressure of 0.5-3.0 MPa, preferably 1.0-2.0 MPa.

[0073] According to one embodiment of the present disclosure, the contact reaction is carried out in a reaction kettle, the stirring rate is 400-1200 rpm, and the amount of the hydrogenation catalyst used is 0.5-1.5 g relative to 1 mL of the aryl formate.

[0074] According to one embodiment of the present disclosure, the contact reaction is carried out in a fixed bed reactor, the mass space velocity of the aryl formate is 0.1-0.3 h -1 .

[0075] According to one embodiment of the present disclosure, the aryl formate has the structure shown in Formula 1:

[0076]

[0077] Ring A is selected from a benzene ring or a C10-C14 fused aromatic ring;

[0078] R1and R2are the same or different and are each independently selected from C1-C4 alkyl;

[0079] n is selected from any integer from 0 to 10;

[0080] Optionally, ring A is selected from one or more of a benzene ring, a naphthalene ring, a phenanthrene ring and an anthracene ring, preferably selected from a benzene ring or a naphthalene ring; C1-C4 alkyl may be, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl or tert-butyl; the aryl formate may be, for example, methyl benzoate, and the target product of the selective hydrogenation reaction of methyl benzoate is benzyl alcohol.

[0081] According to one embodiment of the present disclosure, the contact reaction is carried out in the presence of a solvent, the solvent includes one or more of n-alkanes, preferably includes one or more of n-hexane, n-heptane and cyclohexane, and the amount of the solvent used is conventional in the art.

[0082] According to one embodiment of the present disclosure, the hydrogenation reaction may, for example, include: placing the aryl formate, the solvent and the catalyst into a high-pressure reaction kettle, replacing the air in the reaction kettle with hydrogen, heating to the temperature of the contact reaction, and then starting the reaction under a constant hydrogen pressure.

[0083] The present application will be described in detail below with reference to specific examples. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form.

[0084] The raw materials used in the examples and comparative examples are commercially available and are all of analytical purity unless otherwise specified.

[0085] Test method for conversion rate: analyzed by gas chromatography;

[0086] Test method for selectivity of benzyl alcohol: analyzed by gas chromatography;

[0087] The chromatographic analysis conditions were as follows: capillary column, FID detector, Ar as carrier gas, column, detector, and injector temperatures of 120°C, 150°C, and 120°C, respectively;

[0088] The test method and conditions for the composition of the surface of the catalyst are as follows: XPS, model PHI5000C X-ray photoelectron spectrometer, the test conditions are to place the sample on the sample holder and send it into the pretreatment chamber for vacuum degassing for more than 4.0 hours to remove the substances adsorbed on the sample surface. Mg Kα radiation (1253.6eV) is used as the excitation source, the analyzer energy is 50eV, and the pressure of the analysis chamber is <10 -9 torr, X-ray target voltage was 14.0 kV, and power was 250 W;

[0089] The molar ratio of Al2O3, Cu component calculated as copper element and Mn component calculated as manganese element in the catalyst is the same as the feed ratio.

[0090] Example 1

[0091] Catalyst A1 was hydrogenated using the following steps:

[0092] (1) uniformly mixing copper nitrate, manganese nitrate, and aluminum nitrate with deionized water to obtain a first mixture;

[0093] The molar ratio of aluminum nitrate calculated as Al2O3, copper nitrate calculated as copper element, and manganese nitrate calculated as manganese element is 1:0.16:0.18;

[0094] (2) adding 1 mol / L Na2CO3 solution dropwise to the first mixture at 60°C to adjust the pH value of the mixture to 11;

[0095] (3) aging the mixture obtained in step (2) for 3 h at a temperature of 60° C.

[0096] (4) Cooling the aged mixture and vacuum filtering it, washing the solid with deionized water until the washing liquid is neutral, and then placing the solid in an oven and drying it at 110° C. for 12 h to obtain a catalyst precursor;

[0097] (5) The catalyst precursor was calcined at 500°C for 3 h in an air atmosphere and then reduced at 500°C for 3 h in a hydrogen atmosphere to obtain hydrogenation catalyst A1;

[0098] XPS test was performed on catalyst A1, in which the Cu components on the catalyst surface included Cu and Cu2O, and the Mn components included MnO and Mn3O4. The parameters are listed in Table 1.

[0099] Example 2

[0100] Hydrogenation catalyst A2 was prepared by the method of Example 1, except that in step (2), the base solution was a 1 mol / L NaOH solution, and the pH of the mixture was 11. The catalyst A2 was tested by XPS, in which the Cu component on the surface of the catalyst included Cu and Cu2O, and the Mn component included MnO and Mn3O4. The parameters of the hydrogenation catalyst A2 are listed in Table 1.

[0101] Example 3

[0102] Hydrogenation catalyst A3 was prepared by the method of Example 1, except that in step (2), the pH of the mixture was 9. The catalyst A3 was tested by XPS, in which the Cu component on the surface of the catalyst included Cu and Cu2O, and the Mn component included MnO and Mn3O4. The parameters of the hydrogenation catalyst A3 are listed in Table 1.

[0103] Example 4

[0104] Hydrogenation catalyst A4 was prepared by the method of Example 1, except that in step S1, the molar ratio of aluminum nitrate calculated based on Al2O3, copper nitrate calculated based on copper element, and manganese nitrate calculated based on manganese element was 1:0.16:0.12. The catalyst A4 was tested by XPS, in which the Cu component on the surface of the catalyst included Cu and Cu2O, and the Mn component included MnO and Mn3O4. The parameters of the hydrogenation catalyst A4 are listed in Table 1.

[0105] Example 5

[0106] (1) The copper chloride, manganese chloride, and aluminum chloride were uniformly mixed with deionized water to obtain a first mixture;

[0107] The molar ratio of aluminum chloride calculated based on Al2O3, copper chloride calculated based on copper element, and manganese chloride calculated based on manganese element was 1:0.16:0.18;

[0108] (2) The 1 mol / L KOH solution was added dropwise to the first mixture at 60°C, so that the pH of the mixture was 11;

[0109] (3) The mixture obtained in step (2) was aged for 3h at 60°C;

[0110] (4) The aged mixture was cooled and vacuum filtered, and the solid was washed with deionized water until the washing liquid was neutral. Then the solid was placed in an oven and dried at 105°C for 12h to obtain a catalyst precursor;

[0111] (5) The catalyst precursor was calcined at 500°C for 3h in an air atmosphere, and then reduced at 500°C for 3h in a hydrogen atmosphere to obtain a hydrogenation catalyst A5;

[0112] XPS test was performed on catalyst A5, in which the Cu components on the catalyst surface included Cu and Cu2O, and the Mn components included MnO and Mn3O4. The parameters are listed in Table 1.

[0113] Comparative Example 1

[0114] Catalyst D1 was hydrogenated using the following steps:

[0115] (1) uniformly mixing copper nitrate and aluminum nitrate with deionized water to obtain a first mixture;

[0116] (2) adding 1 mol / L Na2CO3 solution dropwise to the first mixture at 60°C to adjust the pH value of the mixture to 11;

[0117] (3) aging the mixture obtained in step (2) for 3 h at a temperature of 60° C.

[0118] (4) Cooling the aged mixture and vacuum filtering it, washing the solid with deionized water until the washing liquid is neutral, and then placing the solid in an oven and drying it at 110° C. for 12 h to obtain a catalyst precursor;

[0119] (5) calcining the catalyst precursor at 500 °C for 3 h in air atmosphere;

[0120] (6) The solid obtained by calcining in step (5) was ultrasonically mixed with the manganese nitrate solution at 60° C. for 0.5 h, and then a 1 mol / L Na2CO3 solution was added dropwise to adjust the pH value of the mixture to 11; the mixture was aged at 60° C. for 3 h;

[0121] The molar ratio of aluminum nitrate calculated as Al2O3, copper nitrate calculated as copper element, and manganese nitrate calculated as manganese element is 1:0.16:0.18;

[0122] (7) The aged mixture was cooled and vacuum filtered, and the solid was washed with deionized water until the washing liquid was neutral. The solid was then placed in an oven and dried at 110°C for 12 h;

[0123] (8) The solid obtained by drying in step (7) was calcined at 500° C. for 3 h in an air atmosphere and then reduced at 500° C. for 3 h in a hydrogen atmosphere to obtain hydrogenation catalyst D1;

[0124] XPS test was performed on catalyst D1, in which the Cu components on the catalyst surface included Cu and Cu2O, and the Mn components included MnO and Mn3O4. The parameters are listed in Table 1.

[0125] Comparative Example 2

[0126] Catalyst D2 was hydrogenated using the following steps:

[0127] (1) mixing manganese nitrate and aluminum nitrate with deionized water to obtain a first mixture;

[0128] (2) adding 1 mol / L Na2CO3 solution dropwise to the first mixture at 60°C to adjust the pH value of the mixture to 11;

[0129] (3) aging the mixture obtained in step (2) for 3 h at a temperature of 60° C.

[0130] (4) Cooling the aged mixture and vacuum filtering it, washing the solid with deionized water until the washing liquid is neutral, and then placing the solid in an oven and drying it at 110° C. for 12 h to obtain a catalyst precursor;

[0131] (5) calcining the catalyst precursor at 500 °C for 3 h in air atmosphere;

[0132] (6) ultrasonically mixing the solid obtained by calcining in step (5) with a copper nitrate solution, reacting at 60° C. for 0.5 h, and then adding a 1 mol / L Na2CO3 solution dropwise to adjust the pH value of the mixture to 11; aging the mixture at 60° C. for 3 h;

[0133] The molar ratio of aluminum nitrate calculated as Al2O3, copper nitrate calculated as copper element, and manganese nitrate calculated as manganese element is 1:0.16:0.18;

[0134] (7) The aged mixture was cooled and vacuum filtered, and the solid was washed with deionized water until the washing liquid was neutral. The solid was then placed in an oven and dried at 110°C for 12 h;

[0135] (8) The solid obtained by drying in step (7) was calcined at 500° C. for 3 h in an air atmosphere and then reduced at 500° C. for 3 h in a hydrogen atmosphere to obtain hydrogenation catalyst D2;

[0136] XPS test was performed on catalyst D2, in which the Cu components on the catalyst surface included Cu and Cu2O, and the Mn components included MnO and Mn3O4. The parameters are listed in Table 1.

[0137] Comparative Example 3

[0138] The hydrogenation catalyst D3 was prepared by using the method of Example 1, except that, in step (1), the molar ratio of aluminum nitrate calculated as Al2O3, copper nitrate calculated as copper element, and manganese nitrate calculated as manganese element was 1:0.24:0.27. XPS test was performed on catalyst D3, and the Cu component on the catalyst surface included Cu and Cu2O, and the Mn component included MnO and Mn3O4. The parameters of hydrogenation catalyst D3 are listed in Table 1.

[0139] Comparative Example 4

[0140] The catalyst D4 was hydrogenated using the following steps:

[0141] (1) uniformly mixing copper nitrate and aluminum nitrate with deionized water to obtain a first mixture;

[0142] The molar ratio of aluminum nitrate calculated as Al2O3 to copper nitrate calculated as copper element is 1:0.16;

[0143] (2) adding 1 mol / L Na2CO3 solution dropwise to the first mixture at 60°C to adjust the pH value of the mixture to 11;

[0144] (3) aging the mixture obtained in step (2) for 3 h at a temperature of 25° C.

[0145] (4) Cooling the aged mixture and vacuum filtering it, washing the solid with deionized water until the washing liquid is neutral, and then placing the solid in an oven and drying it at 110° C. for 12 h to obtain a catalyst precursor;

[0146] (5) The catalyst precursor was calcined at 500°C for 3 h in an air atmosphere and then reduced at 500°C for 3 h in a hydrogen atmosphere to obtain hydrogenation catalyst D4;

[0147] XPS test was performed on catalyst D4, in which the Cu components on the catalyst surface included Cu and Cu2O, and their parameters are listed in Table 1.

[0148] Comparative Example 5

[0149] Catalyst D5 was hydrogenated using the following steps:

[0150] (1) mixing manganese nitrate and aluminum nitrate with deionized water to obtain a first mixture;

[0151] The molar ratio of aluminum nitrate calculated as Al2O3 to manganese nitrate calculated as manganese element is 1:0.18;

[0152] (2) adding 1 mol / L Na2CO3 solution dropwise to the first mixture at 25°C to adjust the pH value of the mixture to 11;

[0153] (3) aging the mixture obtained in step (2) for 3 h at a temperature of 25° C.

[0154] (4) Cooling the aged mixture and vacuum filtering it, washing the solid with deionized water until the washing liquid is neutral, and then placing the solid in an oven and drying it at 110° C. for 12 h to obtain a catalyst precursor;

[0155] (5) The catalyst precursor was calcined at 500°C for 3 h in an air atmosphere and then reduced at 500°C for 3 h in a hydrogen atmosphere to obtain hydrogenation catalyst D5;

[0156] Catalyst D5 was subjected to XPS testing, in which the Mn components on the catalyst surface included MnO and Mn3O4, and their parameters are listed in Table 1.

[0157] Comparative Example 6

[0158] The hydrogenation catalyst D6 was prepared by the method of Example 1, except that the catalyst was reduced in a hydrogen atmosphere at 400°C for 3 h in step (5). XPS testing was performed on the catalyst D6, and the Cu component on the catalyst surface included Cu and Cu2O, and the Mn component included MnO and Mn3O4. The parameters of the hydrogenation catalyst D6 are listed in Table 1.

[0159] Test Example 1-11

[0160] Catalysts A1-1 to A5-1, and D1-1 to D6-1 prepared in Examples and Comparative Examples.

[0161] The catalyst activity was investigated in a 25 mL stainless steel batch reactor.

[0162] Place 2 mL of methyl benzoate, 10 mL of n-hexane, and 1 g of catalyst into a reaction vessel. After sealing, replace the air in the vessel with hydrogen eight times. After pre-filling with hydrogen and heating to 180°C, initiate the reaction at a hydrogen pressure of 2.0 MPa and a stirring rate of 1000 rpm.

[0163] During the reaction, reaction samples were taken out at regular time intervals and analyzed by gas chromatography for the contents of benzyl alcohol, methyl benzoate, and other possible products. The results are listed in Table 1.

[0164] Test Example 12

[0165] Catalyst A1-1 was used for the hydrogenation of methyl benzoate in a fixed-bed reactor at a temperature of 240 °C, a hydrogen pressure of 1.8 MPa, and a mass space velocity of 0.2 h -1 , the results are listed in Table 1.

[0166] Test Example 13

[0167] The catalyst activity was investigated in a 25 mL stainless steel batch reactor.

[0168] 2 mL of methyl benzoate, 10 mL of n-hexane, and 1 g of catalyst A1-1 were placed in a reaction kettle, sealed, and replaced with hydrogen eight times to remove air from the kettle. After pre-filling with hydrogen and heating to 150°C, the reaction was initiated under a hydrogen pressure of 2.0 MPa with a stirring rate of 1000 rpm. The contents of benzyl alcohol, methyl benzoate, and other possible products were analyzed by gas chromatography. The results are listed in Table 1.

[0169] Table 1

[0170]

[0171]

[0172] According to the data in Table 1, the hydrogenation catalyst containing Al2O3, Cu component and Mn component prepared by the method of the present application can obtain higher catalytic activity and aromatic methanol selectivity for the reaction of hydrogenating aromatic formate to aromatic methanol; further, when the molar ratio of elemental Cu and Cu2O on the catalyst surface is within the preferred range, the components have better synergistic effects, which can further obtain higher catalytic activity and aromatic methanol selectivity.

[0173] The preferred embodiments of the present disclosure are described in detail above. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0174] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0175] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for preparing an aromatic formate hydrogenation catalyst, characterized in that: The method comprises the following steps: S1, mixing a metal source, an alkali source and water to react to obtain a catalyst precursor; S2, heat-treating the catalyst precursor to obtain a pre-product; S3, contacting the pre-product with a hydrogen atmosphere for reduction treatment, wherein the temperature of the reduction treatment is 450-550° C.; The metal source includes an aluminum source, a copper source and a manganese source; The pH value of the mixture obtained by mixing the metal source, the alkali source and the water is 7.0-11.0; The molar ratio of the aluminum source calculated as Al2O3, the copper source calculated as copper element, and the manganese source calculated as manganese element is 1: (0.08-0.20): (0.10-0.22); An XPS test is performed on the catalyst, and the Cu component on the surface of the catalyst includes elemental Cu and Cu2O, and the molar ratio of the elemental Cu to the Cu2O is 1:(0.2-0.8); An XPS test was performed on the catalyst, and the Mn component on the surface of the catalyst included MnO and Mn3O4, and the molar ratio of the MnO to the Mn3O4 was 1:(0.3-0.5).

2. The method according to claim 1, wherein The aluminum source includes one or more of Al(NO3)3, AlCl3 and Al2(SO4)3; The copper source includes one or more of Cu(NO3)2, CuCl2, CuSO4 and Cu(CH3CO2)2; The manganese source includes one or more of Mn(NO3)2, MnCl2, MnSO4 and Mn(CH3CO2)2; The alkali source includes one or more of alkaline carbonates, alkaline bicarbonates and metal hydroxides.

3. The method according to claim 2, wherein: The alkali source includes one or more of Na2CO3, NaHCO3, K2CO3, KHCO3, NaOH and KOH.

4. The method according to claim 1, wherein Step S1 includes: a. mixing the aqueous solution containing the metal source and the alkali source at 10-80° C. to obtain the mixed material; b. Aging the mixture for 2-4 hours at a temperature of 55-65°C.

5. The method according to claim 1, wherein In step S3, the reduction treatment time is 2-4 hours.

6. The method according to claim 1, wherein In step S2, the heat treatment method includes calcination, and the calcination conditions include: time of 2-4 hours, temperature of 400-500° C., and the calcination is carried out in an oxygen-containing atmosphere.

7. An aromatic formate hydrogenation catalyst prepared by the method according to any one of claims 1 to 6.

8. The aromatic formate hydrogenation catalyst according to claim 7, wherein The aromatic formate hydrogenation catalyst comprises Al2O3, a Cu component and a Mn component; The molar ratio of the Al2O3, the Cu component calculated as copper element, and the Mn component calculated as manganese element is 1:(0.08-0.20):(0.10-0.22).

9. A method for hydrogenating an aromatic formate, the method comprising: The aromatic formate, the catalyst and hydrogen are contacted to react, wherein the catalyst comprises the hydrogenation catalyst according to claim 7 or 8.

10. The method according to claim 9, wherein: The conditions for the contact reaction include: a temperature of 100-250° C. and a hydrogen pressure of 0.5-3.0 MPa.

11. The method according to claim 9, wherein The contact reaction is carried out in a reactor at a stirring rate of 400-1200 rpm, and the amount of the hydrogenation catalyst used is 0.5-1.5 g relative to 1 mL of the aromatic formate; or The contact reaction is carried out in a fixed bed reactor, and the mass space velocity of the aromatic formate is 0.1-0.3 h -1 .

12. The method according to claim 9, wherein The aromatic formate has a structure shown in Formula 1: Formula 1 Ring A is selected from a benzene ring or a C10-C14 fused aromatic ring; R1 and R2 are the same or different and are independently selected from C1-C4 alkyl groups; n is any integer selected from 0-10.

13. The method according to claim 9, wherein: The contact reaction is carried out in the presence of a solvent, which includes one or more of n-hexane, n-heptane and cyclohexane.

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