Aromatic formate hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention relates to an aromatic formate hydrogenation catalyst as well as a preparation method and application thereof. The method comprises the following steps: S1, mixing a metal source, an alkali source and water, and reacting to obtain a catalyst precursor; s2, carrying out heat treatment on the catalyst precursor to obtain a pre-product; s3, the pre-product is in contact with a hydrogen atmosphere, reduction treatment is carried out, and the temperature of 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 a mixed material obtained by mixing the metal source, the alkali source and the water is 7.0-11.0; the molar ratio of the aluminum source in terms of Al2O3 to the copper source in terms of copper element to the manganese source in terms of manganese element is 1: (0.08-0.20): (0.10-0.22). The catalyst prepared by the method can be used for selective hydrogenation reaction of aromatic formate under mild conditions, and has the advantages of single raw material, simple operation, good catalytic activity and good aromatic methanol product selectivity.

Description

Technical Field

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

[0002] Benzyl alcohol is a colorless, transparent liquid with a faint aromatic smell. It is an important intermediate for synthetic fragrances and medicines. It is also widely used in the fields of photosensitive, cosmetics, coatings and inks. 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] At present, the method for producing benzyl alcohol in industry is mostly the benzyl chloride hydrolysis method, which is obtained by azeotropic hydrolysis of benzyl chloride and an aqueous solution of alkali. This method is divided into an intermittent hydrolysis method and a continuous hydrolysis method. The intermittent method is to add the reaction raw materials benzyl chloride, water and soda ash into a steel reactor. This steel reactor is equipped with a jacket and a reflux condenser. After the raw materials are added, they are heated and stirred continuously, and then cooled after reflux until CO2 is no longer produced. Then sodium chloride is added to make the alcohol and water more obvious. After separation, industrial-grade benzyl alcohol can be obtained by vacuum distilling the crude alcohol. The yield of benzyl alcohol is 70-72%. The continuous method is to fully mix the benzyl chloride with the aqueous solution of alkali under high temperature (180-275°C) and high pressure (1-6.8MPa), and then enter the hydrolysis zone. This method takes a short time. The advantage of the continuous hydrolysis method is that the reaction rarely produces by-products. The reaction can be carried out in a tower reactor, and the yield of benzyl alcohol is also very high, which can reach 99%. However, the disadvantage of the continuous method is that it consumes more energy than other methods and causes more serious harm to the environment. The benzyl alcohol obtained by the reaction contains chlorine, which will limit its application in food and cosmetics.

[0004] Toluene oxidation is considered as the most promising method for producing benzyl alcohol, but there is no industrial report yet. The problem that toluene oxidation 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 benzaldehyde is expensive (similar to benzyl alcohol) in this method, and is easily oxidized to benzoic acid of room temperature solid state 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, preparing benzyl alcohol by electrochemical electrolysis and biological method, many of these methods are "green chemistry" synthetic routes, but the disadvantage is that the reaction is complicated and the side chain reaction is many, which limits its application to a certain extent. Therefore, it is of great significance to utilize methyl benzoate to generate benzyl alcohol by selective hydrogenation in one step under mild conditions.

[0005] In the 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 cause disadvantages such as difficulty in separating the reaction products. Summary of the invention

[0006] The purpose of the present disclosure is to provide an aromatic formate hydrogenation catalyst and a preparation method and application thereof. The hydrogenation catalyst can carry out a selective hydrogenation reaction of aromatic formate under mild conditions, and has a single raw material, 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 method for preparing an aromatic formate hydrogenation catalyst in a first aspect, 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 with 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 performed in an oxygen-containing atmosphere.

[0023] The second aspect of the present disclosure provides 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] The catalyst is subjected to XPS test, 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).

[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, the catalyst is subjected to an XPS test, 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 hydrogenation of aromatic formate, the method comprising: contacting the aromatic formate, a catalyst and hydrogen for reaction, wherein the catalyst comprises the hydrogenation catalyst described in the second aspect or the third aspect of the present disclosure.

[0030] Optionally, the contact reaction conditions include: a temperature of 100-250° C. and 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 to 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 scheme, 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 reduction treatment, and uses it for the selective hydrogenation reaction of aromatic formate, which can synthesize aromatic methanol by one-step hydrogenation under mild conditions, and has the advantages of single reactant raw materials, low impurity content of products, 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 specific embodiments of the present disclosure are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0042] The 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 invention adopts a co-precipitation method to prepare a catalyst for hydrogenation of aromatic formate, and controls the pH value of the mixed material, so that the components in the prepared catalyst can be evenly distributed, and controls the molar ratio of elemental Cu and Cu2O on the catalyst surface by controlling the conditions of the reduction treatment, which is beneficial to the reaction of hydrogenating aromatic formate to prepare 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 more than two kinds at the same time, there is no restriction 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 an 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 in a manner that: at 10-80° C., the aqueous solution containing the alkali source is added dropwise to the aqueous solution containing the metal source; in order to make the coprecipitation reaction more complete, all mixing is performed under stirring;

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

[0058] c. Cooling the aged mixed material and performing solid-liquid separation, washing the solid until the washing liquid is neutral at room temperature, and the solid-liquid separation method is conventional in the art, for example, 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] The second aspect of the present disclosure provides 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] The catalyst is subjected to XPS test, 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).

[0066] The hydrogenation catalyst disclosed in the present invention comprises Al2O3, a Cu component and a Mn component with a specific composition, and has elemental Cu and Cu2O in a specific molar ratio on the catalyst surface, and can realize the selective hydrogenation reaction of aromatic formate under mild conditions to generate aromatic methanol in one step; and can obtain higher catalytic activity than the manganese-based catalysts in the prior art, and can obtain higher aromatic methanol selectivity than the copper-based catalysts in the prior art.

[0067] According to one embodiment of the present disclosure, the 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, the catalyst is subjected to XPS testing, and the molar ratio of the single substance Cu to Cu2O on the surface of the catalyst is 1:(0.3-0.5); the Mn component on the surface of the catalyst includes MnO and Mn3O4, and the molar ratio of MnO to Mn3O4 is 1:(0.3-0.5). The components in the hydrogenation catalyst have a synergistic effect, and using it in the reaction of hydrogenating aromatic formate to produce aromatic methanol can obtain higher 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 hydrogenation of aromatic formate, the method comprising: contacting the aromatic formate, a catalyst and hydrogen for reaction, wherein the catalyst comprises the hydrogenation catalyst described in the second aspect or the 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.; 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 reactor with 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 aromatic formate.

[0074] According to one embodiment of the present disclosure, 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 .

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

[0076]

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

[0078] R1 and R2 are the same or different and are independently selected from C1-C4 alkyl groups;

[0079] n is any integer selected 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 a benzene ring or a naphthalene ring; the C1-C4 alkyl group may be, for example, a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group or a tert-butyl group; the aromatic 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 normal alkanes, preferably includes one or more of normal hexane, normal 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 include, for example, placing benzoic acid ester, solvent and catalyst into a high-pressure reactor, replacing them with hydrogen, removing the air in the reactor, heating to a contact reaction temperature, and starting the reaction under a constant hydrogen pressure.

[0083] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form.

[0084] Unless otherwise specified, the raw materials used in the examples and comparative examples were obtained from commercial sources and were of analytical grade.

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

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

[0087] The above chromatographic analysis conditions are 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: XPS, model PHI5000C X-ray photoelectron spectrometer, the test conditions are to place the sample on the sample rack 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 rays (1253.6eV) are 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 is 14.0 kV, power is 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) 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 a 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 hours 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) calcining the catalyst precursor at 500° C. for 3 h in an air atmosphere and then reducing it 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, and their parameters are listed in Table 1.

[0099] Example 2

[0100] The hydrogenation catalyst A2 was prepared by the method of Example 1, except that in step (2), the alkaline source solution was a solution of NaOH with a concentration of 1 mol / L, and the pH value of the mixed solution was made to be 11. The catalyst A2 was subjected to XPS test, wherein 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 A2 are listed in Table 1.

[0101] Example 3

[0102] The hydrogenation catalyst A3 was prepared by the method of Example 1, except that in step (2), the pH value of the mixed solution was 9. The catalyst A3 was subjected to XPS test, wherein 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 A3 are listed in Table 1.

[0103] Example 4

[0104] The hydrogenation catalyst A4 was prepared by the method of Example 1, except that, in step S1, the molar ratio of aluminum nitrate calculated as Al2O3, copper nitrate calculated as copper element and manganese nitrate calculated as manganese element was 1:0.16:0.12. Catalyst A4 was subjected to XPS test, wherein 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 A4 are listed in Table 1.

[0105] Example 5

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

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

[0108] (2) adding a 1 mol / L KOH solution dropwise to the first mixture at 60° C. to adjust the pH value of the mixture to 11;

[0109] (3) aging the mixture obtained in step (2) for 3 hours at a temperature of 60° C.;

[0110] (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 105° C. for 12 h to obtain a catalyst precursor;

[0111] (5) calcining the catalyst precursor at 500° C. for 3 h in an air atmosphere, and then reducing it at 500° C. for 3 h 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, and the parameters are listed in Table 1.

[0113] Comparative Example 1

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

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

[0116] (2) adding a 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 hours 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 an air atmosphere;

[0120] (6) the solid obtained by calcining 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 mixed solution 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) 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;

[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 a 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, and their parameters are listed in Table 1.

[0125] Comparative Example 2

[0126] The 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 a 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 hours 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 an air atmosphere;

[0132] (6) ultrasonically mixing the solid obtained by calcining 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 mixed solution 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) 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;

[0135] (8) the solid obtained by drying 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 a 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, and their 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. The catalyst D3 was subjected to XPS test, wherein 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 D3 are listed in Table 1.

[0139] Comparative Example 4

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

[0141] (1) 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 a 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 hours 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) calcining the catalyst precursor at 500° C. for 3 h in an air atmosphere and then reducing it at 500° C. for 3 h in a hydrogen atmosphere to obtain a 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 a 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 hours 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) calcining the catalyst precursor at 500° C. for 3 h in an air atmosphere and then reducing it at 500° C. for 3 h in a hydrogen atmosphere to obtain a hydrogenation catalyst D5;

[0156] XPS test was performed on catalyst D5, 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 in step (5), the catalyst was reduced in a hydrogen atmosphere at 400°C for 3 h to obtain the catalyst. XPS test was performed on the catalyst D6, wherein the Cu component on the catalyst surface includes Cu and Cu2O, and the Mn component includes 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, D1-1 to D6-1 prepared in the examples and comparative examples.

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

[0162] 2 mL of methyl benzoate, 10 mL of n-hexane and 1 g of catalyst were placed in a reactor, which was sealed and replaced with hydrogen 8 times to remove the air in the reactor. After pre-filling with hydrogen, the reactor was heated to 180°C and the reaction was started under a hydrogen pressure of 2.0 MPa with 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, which was sealed and replaced with hydrogen 8 times to remove the air in the kettle. After pre-charging with hydrogen and heating to 150° C., the reaction was started under a hydrogen pressure of 2.0 MPa, with a stirring rate of 1000 rpm. The benzyl alcohol content, methyl benzoate content, and other possible product contents were analyzed by gas chromatography, and 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 effect, and 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 in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope 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. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0175] In addition, 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).

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, and preferably includes one or more of Na2CO3, NaHCO3, K2CO3, KHCO3, NaOH and KOH.

3. The method according to claim 1, wherein: Step S1 includes: a. mixing the aqueous solution containing the metal source with 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.

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

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

6. Aromatic formate hydrogenation catalyst prepared by the method described in any one of claims 1 to 5.

7. An aromatic formate hydrogenation catalyst, characterized in that: 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); The catalyst is subjected to XPS test, 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).

8. The aromatic formate hydrogenation catalyst according to claim 7, wherein Performing an XPS test on the catalyst, the Mn component on the surface of the catalyst includes manganese oxide; Optionally, the catalyst is subjected to an XPS test, 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).

9. A method for hydrogenating 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 any one of claims 6 to 8.

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

11. The method according to claim 9, wherein: The aromatic formate has a structure shown in 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 to 10; 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.

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