Supported catalyst, preparation thereof and application of supported catalyst in reaction for synthesizing methyl glyoxylate from methyl glycolate

Abstract

The invention belongs to the technical field of organic synthesis, and relates to a supported catalyst, a preparation method thereof, and an application of the supported catalyst in a reaction for synthesizing methyl glyoxylate from methyl glycolate, the supported catalyst comprises a carrier, and an active metal component and an auxiliary agent component which are supported on the carrier; wherein the active metal component is vanadium; the auxiliary agent component is selected from at least one of silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, cerium, cobalt, magnesium, calcium, barium, lanthanum, boron, gallium, germanium or indium. Compared with the prior art, the active metal and the auxiliary agent of the prepared catalyst are concentrated on one layer of the surface of the carrier and are distributed in an eggshell shape, methyl glycolate completes adsorption, reaction and desorption on the surface of the catalyst, a large amount of excessive oxidation products CO and CO2 are prevented from being generated, and the yield of methyl glyoxylate is increased.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, and relates to a supported catalyst, its preparation, and its application in the reaction of synthesizing methyl glyoxylate from methyl glycolate. Background Technology

[0002] Methyl glycolate (MG), also known as methyl glycolate, is a colorless, transparent liquid with two basic functional groups: a hydroxyl group and an ester group. It can undergo oxidation to produce methyl glyoxylate. Methyl glyoxylate (MGO) is an important organic synthesis intermediate, possessing the chemical properties of both aldehydes and esters. It can undergo various reactions, particularly hydrolysis to prepare glyoxylic acid (GOA). Glyoxylic acid is an important organic intermediate in the synthesis of fragrances, dyes, food products, and paints, and can be used to produce vanillin, mandelic acid, antibiotics, and allantoin. With the development of coal-to-ethylene glycol technology, the intermediate product methyl glycolate provides a sufficient and inexpensive raw material for the synthesis of methyl glyoxylate. The rational utilization of methyl glycolate can enrich the ethylene glycol industry chain while enabling the refinement and high added value of downstream products, which has profound significance for promoting the development of the coal-to-ethylene glycol industry.

[0003] Traditional methods for preparing glyoxylic acid have the following problems: (1) Oxalic acid electrolysis method: oxalic acid aqueous solution is electrolyzed to obtain glyoxylic acid aqueous solution, which is then evaporated, concentrated, and frozen to obtain glyoxylic acid. However, the glyoxylic acid product obtained by this method has poor quality, unstable properties, and high power consumption. (2) Maleic anhydride ozone oxidation-reduction method: maleic anhydride is used as raw material, and glyoxylic acid is obtained through hydrolysis and oxidation. However, this process has high production costs, high requirements for ozone equipment, and poor safety. (3) Glyoxal nitric acid oxidation method: the glyoxylic acid product obtained by this method has poor quality, contains impurities such as glyoxal, requires the use of nitric acid, causes severe equipment corrosion, emits nitrogen oxides, and puts great pressure on environmental protection.

[0004] In recent years, with the development of coal-to-ethylene glycol technology, the sources of the intermediate product methyl glycolate have become increasingly diverse. Reports on the synthesis of methyl glyoxylate or glyoxylic acid from methyl glycolate as a raw material are increasing. Patent CN114656360 uses Ni... x M y P zUsing a composite oxide as a catalyst, methyl glycolate is synthesized from methyl glycolate, achieving a methyl glycolate conversion rate of 99% and a glyoxylate selectivity of 85.4%. Patent CN107876055 uses a composite oxide formed from ferric oxide and cobalt tetroxide as a catalyst in a fixed-bed reactor to catalyze the oxidation of methyl glycolate, producing glyoxylic acid. The conversion rate of methyl glycolate is 67-99%, and the selectivity of the liquid-phase product glyoxylic acid is 55-100%. Patent CN112778118 uses a nitrogen-doped carbon-supported metal catalyst as an oxidation catalyst and a solid acid as a hydrolysis catalyst. Methyl glycolate and a mixed solvent are passed through the catalyst to react and obtain glyoxylic acid.

[0005] Patent CN116059996 uses vanadium as the active component and alumina, zirconium oxide, and cerium oxide as carriers, achieving a methyl glycolate conversion rate of 90.5% and a glyoxylate selectivity of 70.7%. The patent indicates that a large amount of CO is generated during the methyl glycolate oxidation process. x The generation of (CO and CO2) has a selectivity of up to 30-40%, which greatly reduces the utilization rate of the raw material methyl glycolate, resulting in a low overall selectivity of methyl glyoxylate.

[0006] Currently, the synthesis of methyl glyoxylate or glyoxylic acid from methyl glycolate is a complex process, with difficulties in separating and purifying glyoxylic acid, and the presence of gaseous byproduct CO. x The high selectivity and low yield of the target product glyoxylic acid, coupled with the low utilization rate of the raw material methyl glycolate, significantly increase the production cost of glyoxylic acid. Summary of the Invention

[0007] The purpose of this invention is to provide a catalyst for the synthesis of methyl glyoxylate from methyl glycolate, its preparation method, and its application. This invention addresses the problem that, during the synthesis of methyl glyoxylate using methyl glycolate oxidation catalysts, excessive oxidation at high temperatures can easily occur, leading to the formation of acids or further oxidation to produce byproducts such as carbon dioxide and carbon monoxide. By using the catalyst and application conditions of this invention, the conversion rate, selectivity, and yield of methyl glyoxylate are significantly improved, reaching over 99%.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A first aspect of the present invention provides a supported catalyst, comprising a support and an active metal component and an auxiliary component supported on the surface of the support;

[0010] The active metal component is vanadium, with a mass loading of 0.3% to 20%.

[0011] The auxiliary component is selected from at least one of silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, cerium, cobalt, magnesium, calcium, barium, lanthanum, boron, gallium, germanium or indium, and the mass loading is 0.1% to 15%.

[0012] The active metal component and the auxiliary component are concentrated on the catalyst surface, with a distribution depth of 100-1200 μm.

[0013] The active metal and additives of the catalyst of this invention are concentrated on the surface layer of the support in an eggshell-shaped distribution, and are maintained at a certain distribution depth. This is conducive to the adsorption, reaction and desorption of methyl glycolate on the catalyst surface, avoiding the excessive generation of CO and CO2 products, and improving the yield of methyl glyoxylate.

[0014] In some preferred embodiments, the auxiliary component X is selected from at least one of silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, calcium, barium, lanthanum, boron, gallium, germanium, or indium.

[0015] Furthermore, the support is selected from at least one of silica, alumina, MCM-41, β-zeolite, Y-type zeolite, ZSM-5, mordenite, TS-1 zeolite, or SAPO-34 zeolite; the mass loading of the support is 65-99.6%.

[0016] In some preferred embodiments, the carrier S is selected from at least one of silica, alumina, MCM-41, Y-type molecular sieve, ZSM-5, TS-1 molecular sieve or SAPO-34 molecular sieve.

[0017] In some preferred embodiments, the active metal component and the auxiliary component are distributed at a depth of 200–1000 μm on the catalyst surface.

[0018] A second aspect of the present invention provides a method for preparing a supported catalyst, comprising the following steps:

[0019] S1: The vanadium source and the regulator are dissolved in water to obtain a solution and a conditioning solution, respectively. The solution and the conditioning solution are mixed to obtain an impregnation solution. A carrier is added for impregnation to obtain a solid.

[0020] S2: The obtained solid is impregnated in an additive solution, dried, and calcined to obtain the supported catalyst.

[0021] In some specific embodiments, step S1 includes:

[0022] S1-1: Dissolve the vanadium source in water to obtain a vanadium source solution; mix the regulator with water to obtain a regulator solution;

[0023] S1-2: Add the regulator solution dropwise into the vanadium source solution while stirring continuously to obtain a mixed aqueous solution of vanadium source and regulator;

[0024] S1-3: Add the carrier to the mixed aqueous solution for impregnation.

[0025] Further, in step S1, the vanadium source is selected from at least one of ammonium metavanadate, sodium metavanadate, or potassium metavanadate.

[0026] Further, in step S1, the regulator is used to adjust the pH of the impregnation solution to 8.5–12.5.

[0027] In some preferred embodiments, the pH of the impregnation solution is adjusted to 10.5–12.5.

[0028] Furthermore, the regulator is selected from at least one of sodium hydroxide, potassium hydroxide, sodium phosphate, sodium monohydrogen phosphate, potassium phosphate, potassium monohydrogen phosphate, diammonium hydrogen phosphate, ammonium hydrogen phosphate, sodium formate, and potassium formate.

[0029] In some specific embodiments, in step S1-1, the concentration of the regulator solution is 0.5 mol / L.

[0030] Further, in step S1, during the impregnation process, the impregnation temperature is room temperature and the impregnation time is 2 to 4 hours; then, drying is carried out, during which the drying temperature is 60 to 105°C and the drying time is 12 to 24 hours.

[0031] Furthermore, in step S2, the auxiliary agent in the auxiliary agent solution is a soluble salt containing auxiliary agent components.

[0032] Furthermore, the additive is selected from at least one of silver nitrate, ammonium molybdate, yttrium nitrate, bismuth nitrate, ammonium metatungstate, manganese nitrate, ammonium niobate, zinc nitrate, zirconium nitrate, cerium nitrate, cobalt nitrate, magnesium nitrate, calcium nitrate, barium nitrate, lanthanum nitrate, ammonium borate, gallium nitrate, ammonium hexafluorogermanate, and indium nitrate.

[0033] Furthermore, in step S2, during the impregnation process, the impregnation temperature is room temperature and the impregnation time is 2 to 4 hours; then, drying is carried out, during which the drying temperature is 80 to 150°C and the drying time is 8 to 16 hours.

[0034] Furthermore, in step S2, during the roasting process, the roasting atmosphere is air, the roasting temperature is 400–800℃, and the roasting time is 3–8 hours.

[0035] In some preferred embodiments, the roasting temperature is 500–700°C during the roasting process.

[0036] This invention introduces a regulator during the vanadium source impregnation process to make the carrier surface alkaline. When the additives are reloaded, they will precipitate prematurely upon encountering the alkali and become fixed on the carrier surface, thus forming an eggshell-shaped structure. This preparation method has the advantages of being simple and producing a stable and easily formed eggshell-shaped structure.

[0037] The OH- present in the regulator solution selected in this invention - This allows the vanadium source to be more stably distributed in the solution. At the same time, the acidity and alkalinity of the support surface are modified. By controlling the drying temperature and drying time, the migration depth of the metal components and active components are synergistically adjusted, thereby obtaining catalysts with different eggshell thicknesses.

[0038] A third aspect of the invention provides an application of a supported catalyst, including using the supported catalyst in the catalytic reaction of methyl glycolate to methyl glyoxylate.

[0039] Furthermore, in the catalytic reaction, the reaction temperature is 160–320°C and the reaction pressure is 0.05–1.5 MPa.

[0040] In some preferred embodiments, the catalytic reaction is carried out at a temperature of 180–300°C and a pressure of 0.05–1.0 MPa.

[0041] Furthermore, the molar ratio of methyl glycolate to oxygen is 1:(0.5-20).

[0042] In some preferred embodiments, the molar ratio of methyl glycolate to oxygen in the catalytic reaction is 1:(0.6-16).

[0043] Furthermore, the liquid hourly space velocity (LISH) of the methyl glycolate is 0.1–2.5 h⁻¹. -1 .

[0044] In some preferred embodiments, the liquid hourly space velocity (LHSV) of the methyl glycolate in the catalytic reaction is 0.15–2.0 h⁻¹. -1 .

[0045] Furthermore, in the catalytic reaction, the reaction gas phase consists of oxygen-containing gas and gaseous methyl glycolate, wherein the oxygen-containing gas has a volume fraction of 5-30%, and the remainder is nitrogen.

[0046] In some preferred embodiments, the oxygen-containing gas has an oxygen volume fraction of 10-25%.

[0047] The eggshell-shaped catalyst prepared in this invention uses only vanadium as the active component, and at a low content of 0.3–20 wt%, and reacts at a reaction temperature of 220°C, a reaction pressure of 0.15 MPa, and a reaction time of 0.7 h. -1Under reaction conditions with a liquid hourly space velocity of methyl glycolate, a high conversion rate of 99.7–99.9%, a high selectivity of 98.4–99.2%, and a high yield of 98.2–99.1% can be achieved.

[0048] Compared with the prior art, the present invention has the following characteristics:

[0049] 1) This invention treats the surface of the support with alkalinity while loading the active component, so that the subsequently loaded auxiliary components can be concentrated together with the active component on the surface layer of the support. The distribution depth of the active component and the auxiliary components can be controlled by the preparation process to obtain eggshell-shaped catalysts with different active layer thicknesses. This allows methyl glycolate to complete adsorption, reaction and desorption on the catalyst surface during catalytic oxidation, avoiding the excessive generation of CO and CO2 products, thereby significantly improving the yield of methyl glyoxylate.

[0050] 2) Using the eggshell-shaped catalyst prepared by this invention, the active component is vanadium, and at a low content of 0.3-20 wt%, at a reaction temperature of 220℃, a reaction pressure of 0.15 MPa, and a reaction time of 0.7 h... -1 Under reaction conditions with a liquid hourly space velocity of methyl glycolate, a high conversion rate of 99.7–99.9%, a high selectivity of 98.4–99.2%, and a high yield of 98.2–99.1% can be achieved.

[0051] 3) When the catalyst prepared by this invention is used to synthesize methyl glyoxylate from methyl glycolate, the product distribution is simple, the gas phase components such as COx are easy to separate, and the selectivity of the by-product liquid phase product does not exceed 0.4%, which is beneficial to obtaining high-purity methyl glyoxylate or glyoxylic acid products. Attached Figure Description

[0052] Figure 1 Microscopic characterization of the central cross-section of a V-Ag / silica catalyst with an eggshell-shaped structure prepared in Example 1;

[0053] Figure 2 Microscopic characterization of the central cross-section of a supported catalyst prepared in Comparative Example 1;

[0054] Figure 3 Microscopic characterization of the central cross-section of a supported catalyst prepared for Comparative Example 2. Detailed Implementation

[0055] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0056] A method for preparing a supported catalyst includes the following steps:

[0057] S1: The vanadium source and the regulator are dissolved in water to obtain a solution and a conditioning solution, respectively. The solution and the conditioning solution are mixed to obtain an impregnation solution. A carrier is added for impregnation to obtain a solid.

[0058] S2: The obtained solid is impregnated in an additive solution, dried, and calcined to obtain the supported catalyst.

[0059] This embodiment is implemented based on the technical solution of the present invention, and provides detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the following embodiment.

[0060] The following are more detailed implementation examples, which further illustrate the technical solution of the present invention and the technical effects that can be obtained.

[0061] In the following embodiments, unless otherwise specified, the raw materials, reagents or processing techniques are all conventional commercial products or conventional processing techniques in the art.

[0062] In the following embodiments, the additives silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, cerium, cobalt, magnesium, calcium, barium, lanthanum, boron, gallium, germanium, or indium are added in the form of corresponding soluble salts, such as nitrates, oxalates, sulfates, etc.; more specifically, they include silver nitrate, ammonium molybdate, yttrium nitrate, bismuth nitrate, ammonium metatungstate, manganese nitrate, ammonium niobate, zinc nitrate, zirconium nitrate, cerium nitrate, cobalt nitrate, magnesium nitrate, calcium nitrate, barium nitrate, lanthanum nitrate, ammonium borate, gallium nitrate, ammonium hexafluorogermanate, and indium nitrate used in the following embodiments.

[0063] Example 1:

[0064] A V-Ag / silica catalyst with an eggshell-shaped structure is prepared by the following steps:

[0065] S1-1: Add 1.44g of ammonium metavanadate to deionized water and stir until completely dissolved, and record this as solution A; add sodium hydroxide to deionized water and stir until completely dissolved to prepare solution B with a concentration of 0.5mol / L;

[0066] S1-2: Add solution B dropwise to solution A and stir continuously until the pH value reaches 11.5, then label it solution C;

[0067] S1-3: Add 10g of carrier silica to solution C, stir well, let stand for 2.5h, and then dry at 80℃ for 12h to obtain solid a;

[0068] S2: Add 1.97g of silver nitrate to deionized water and stir until completely dissolved. Add solid a and stir evenly. Let stand for 3h, then dry at 110℃ for 10h, and then calcine at 600℃ for 5h in air atmosphere to obtain the catalyst product. Take the catalyst sample for atomic emission spectrometry elemental analysis by inductively coupled plasma optical emission spectrometry (ICP-OES). The distribution depth of active metal components and auxiliary components on the catalyst surface is analyzed and characterized by OLYMPUSBX51 microscope. The results are shown in Table 1.

[0069] Examples 2-25:

[0070] A VX / S catalyst with an eggshell-shaped structure is prepared in a method that differs from Example 1 only in that the corresponding components and / or amounts in Example 1 are replaced according to the components and / or amounts in Table 1, for example:

[0071] Example 12

[0072] A V-Mg / silica catalyst with an eggshell-shaped structure is prepared by the following steps:

[0073] S1-1: Add 4.26g of ammonium metavanadate to deionized water and stir until completely dissolved, and record this as solution A; add potassium hydroxide to deionized water and stir until completely dissolved to prepare solution B with a concentration of 0.5mol / L;

[0074] S1-2: Add solution B dropwise to solution A and stir continuously until the pH value reaches 10.8, then denote it as solution C;

[0075] S1-3: Add 10g of carrier silica to solution C, stir well, let stand for 3.5h, and then dry at 90℃ for 16h to obtain solid a;

[0076] S2: Add 0.84g of magnesium nitrate to deionized water and stir until completely dissolved. Add solid a and stir evenly. Let stand for 2.5h, then dry at 120℃ for 12h, and then calcine at 650℃ for 4.5h in air atmosphere to obtain the catalyst product. Take the catalyst sample for atomic emission spectrometry elemental analysis by inductively coupled plasma optical emission spectrometry (ICP-OES). The distribution depth of active metal components and auxiliary components on the catalyst surface is analyzed and characterized by OLYMPUSBX51 microscope. The results are shown in Table 1.

[0077] Example 20

[0078] A V-Ag-Y / MCM-41 catalyst with an eggshell-shaped structure is prepared by the following steps:

[0079] S1-1: Add 4.66g of potassium metavanadate to deionized water and stir until completely dissolved, and record this as solution A; add potassium hydroxide to deionized water and stir until completely dissolved to prepare solution B with a concentration of 0.5mol / L;

[0080] S1-2: Add solution B dropwise to solution A and stir continuously until the pH value reaches 12.5, then label it solution C;

[0081] S1-3: Add 10g of carrier MCM-41 to solution C, stir well, let stand for 2.5h, and then dry at 105℃ for 24h to obtain solid a;

[0082] S2: Add 0.13g of silver nitrate and 1.89g of yttrium nitrate to deionized water and stir until completely dissolved. Add solid a and stir evenly. Let stand for 3 hours, then dry at 130℃ for 14 hours. Then calcine at 550℃ in air for 8 hours to obtain the catalyst product. Take the catalyst sample for atomic emission spectrometry elemental analysis by inductively coupled plasma optical emission spectrometry (ICP-OES). The distribution depth of active metal components and auxiliary components on the catalyst surface is analyzed and characterized by OLYMPUSBX51 microscope. The results are shown in Table 1.

[0083] This invention provides a catalyst for the synthesis of methyl glyoxylate from methyl glycolate. The catalyst is prepared by using vanadium as the active metal and at least one of silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, cerium, cobalt, magnesium, calcium, barium, lanthanum, boron, gallium, germanium, or indium as an auxiliary agent X. It is combined with one or more of sodium hydroxide, potassium hydroxide, sodium phosphate, sodium monohydrogen phosphate, potassium phosphate, potassium monohydrogen phosphate, diammonium hydrogen phosphate, ammonium hydrogen phosphate, sodium formate, and potassium formate as a modifier, and supported by silica, alumina, MCM-41, β-zeolite, Y-type zeolite, ZSM-5, mordenite, TS-1 zeolite, and SAPO-34 zeolite to successfully obtain the VX / S catalyst.

[0084] Table 1 Catalyst composition

[0085]

[0086]

[0087]

[0088] Comparative Example 1:

[0089] A supported catalyst, the preparation method of which differs from that of Example 1 only in that no modifier is added, otherwise it is the same as that of Example 1; specifically, it includes the following steps:

[0090] S1: Add 1.44g of ammonium metavanadate to deionized water and stir until completely dissolved. This solution is denoted as solution A.

[0091] S2: Add 10g of carrier silica to solution A, stir well, let stand for 2.5h, and then dry at 80℃ for 12h to obtain solid a;

[0092] S3: 1.97g of silver nitrate was added to deionized water and stirred until completely dissolved. Solid a was added and stirred evenly. The mixture was allowed to stand for 3 hours, then dried at 110℃ for 10 hours, and then calcined at 600℃ in air for 5 hours to obtain the catalyst product. Catalyst samples were taken for elemental analysis by ICP-OES atomic emission spectrometry. The distribution depth of the active metal component and the auxiliary component on the catalyst surface was analyzed and characterized by an OLYMPUS X51 microscope. The results are shown in Table 1. The experiment shows that without the regulator, the active metal and the auxiliary are uniformly distributed and no eggshell layer appears.

[0093] Comparative Example 2:

[0094] A supported catalyst, the preparation method of which differs from that of Example 1 only in that the modifier sodium hydroxide is added after silver nitrate impregnation, specifically including the following steps:

[0095] S1: Add 1.44g of ammonium metavanadate to deionized water and stir until completely dissolved. This solution is denoted as solution A.

[0096] S2: Add 10g of carrier silica to solution C, stir well, let stand for 2.5h, and then dry at 80℃ for 12h to obtain solid a;

[0097] S3: Add 1.97g of silver nitrate to deionized water and stir until completely dissolved. Add solid a and stir evenly. Let stand for 3 hours to obtain slurry A.

[0098] S4: Add sodium hydroxide to deionized water and stir until completely dissolved to prepare a solution B with a concentration of 0.5 mol / L;

[0099] S5: Add solution B dropwise into slurry A and stir continuously until the pH value reaches 11.5, then label it solution C;

[0100] The catalyst was then dried at 110℃ for 10 hours, followed by calcination at 600℃ in air for 5 hours to obtain the final catalyst product. Catalyst samples were subjected to ICP-OES atomic emission spectrometry for elemental analysis, and the distribution depth of the active metal and auxiliary components on the catalyst surface was analyzed and characterized using an OLYMPUS BX51 microscope. The results are shown in Table 1. Experiments show that when the timing of the regulator addition is changed, the active metal and auxiliary components are evenly distributed, and no eggshell layer appears.

[0101] Application Example 1:

[0102] This application example is used to examine the apparent morphological characteristics of the catalysts prepared in Examples 1-25 and Comparative Examples 1-2.

[0103] Microscopic observation revealed that the active metal components and auxiliary components in Examples 1-25 were only distributed within a depth range of 100–1200 μm on the catalyst surface (microscopic characterization results of Example 1 are shown below). Figure 1 (as shown in the figure), however, in Comparative Examples 1 and 2, the active metal component and the auxiliary component are uniformly distributed throughout the catalyst (the microscopic characterization results of Comparative Examples 1 and 2 are shown in the figure). Figure 2 and Figure 3 As shown in the figure, the average radius of the catalysts in Comparative Examples 1 and 2 is 2000-2500 μm.

[0104] It can be seen that the VX / S catalyst prepared by the present invention has a distinct eggshell-shaped structure compared with the comparative example. Furthermore, it can be seen from Comparative Example 1 and Comparative Example 2 that the use of the regulator and the timing of its use have a significant impact on the formation of this structure. The eggshell-shaped structure cannot be obtained without using the regulator or by adding the regulator after impregnation with the auxiliary agent.

[0105] Application Example 2:

[0106] The application of a VX / S catalyst with an eggshell-like structure in the synthesis of methyl glyoxylate from methyl glycolate includes the following process:

[0107] The VX / S catalyst was ground and sieved to 10-40 mesh. 2 g of the catalyst was loaded into a fixed-bed reactor. The reaction temperature was 220℃, the reaction pressure was 0.15 MPa, and the liquid hourly space velocity (LHSV) of methyl glycolate was 0.7 h⁻¹. -1 The molar ratio of oxygen to methyl glycolate in the oxygen-containing gas was 2.0:1. Methyl glycolate was pumped into the system, mixed and vaporized with the oxygen-containing gas (oxygen content 21 vol%), and then entered the reactor. After reacting in the catalyst bed and undergoing condensation and gas-liquid separation at around -5°C, the product liquid was obtained in the product tank. After the reaction stabilized, the product liquid and the tail gas were respectively subjected to component analysis by flame ionization detector (FID) gas chromatograph and thermal conductivity detector (TCD) gas chromatograph. The reaction results are shown in Table 2.

[0108] Table 2 Reaction Effects

[0109]

[0110]

[0111] As can be seen from Table 2, the eggshell-shaped catalyst prepared in this invention, with vanadium as the only active component and at a low content of 0.3–20 wt%, can achieve the desired reaction temperature of 220°C, reaction pressure of 0.15 MPa, and reaction time of 0.7 h. -1 Under reaction conditions with a liquid hourly space velocity of methyl glycolate, a high conversion rate of 99.7–99.9%, a high selectivity of 98.4–99.2%, and a high yield of 98.2–99.1% can be achieved.

[0112] This is significantly related to the eggshell-shaped structure of the catalyst of the present invention. See Comparative Examples 1 and 2 for their catalytic effects, which are significantly lower than those of Example 1. This is because the auxiliary component of the present invention can be concentrated together with the active component on the surface layer of the support, thereby allowing methyl glycolate to complete adsorption, reaction, and desorption on the catalyst surface during catalytic oxidation, avoiding the excessive generation of CO and CO2, thus significantly improving the yield of methyl glyoxylate.

[0113] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A supported catalyst, characterized in that, Includes the carrier and the active metal components and additive components loaded on the surface of the carrier; The active metal component is vanadium, with a mass loading of 0.3% to 20%. The auxiliary component is selected from at least one of silver, molybdenum, yttrium, bismuth, tungsten, manganese, niobium, zinc, zirconium, cerium, cobalt, magnesium, calcium, barium, lanthanum, boron, gallium, germanium or indium, and the mass loading is 0.1% to 15%. The active metal component and the auxiliary component are concentrated on the catalyst surface, with a distribution depth of 100-1200 μm.

2. The supported catalyst according to claim 1, characterized in that, The support is selected from at least one of silica, alumina, MCM-41, β-zeolite, Y-type zeolite, ZSM-5, mordenite, TS-1 zeolite, or SAPO-34 zeolite; the mass loading of the support is 65-99.6%.

3. A method for preparing a supported catalyst as described in claim 1 or 2, characterized in that, The method includes the following steps: S1: The vanadium source and the regulator are dissolved in water to obtain a solution and a conditioning solution, respectively. The solution and the conditioning solution are mixed to obtain an impregnation solution. A carrier is added for impregnation to obtain a solid. S2: The obtained solid is impregnated in an additive solution, dried, and calcined to obtain the supported catalyst.

4. The method for preparing the supported catalyst according to claim 3, characterized in that, In step S1, the vanadium source is selected from at least one of ammonium metavanadate, sodium metavanadate, or potassium metavanadate.

5. The method for preparing the supported catalyst according to claim 3, characterized in that, In step S1, the regulator is used to adjust the pH of the impregnation solution to 8.5–12.5; Preferably, the regulator is selected from at least one of sodium hydroxide, potassium hydroxide, sodium phosphate, sodium monohydrogen phosphate, potassium phosphate, potassium monohydrogen phosphate, diammonium hydrogen phosphate, ammonium hydrogen phosphate, sodium formate, and potassium formate.

6. The method for preparing the supported catalyst according to claim 3, characterized in that, In step S2, the auxiliary agent in the auxiliary agent solution is a soluble salt containing auxiliary agent components.

7. The method for preparing the supported catalyst according to claim 3, characterized in that, In step S1, the impregnation temperature is room temperature and the impregnation time is 2-4 hours; then the drying process is carried out at a temperature of 60-105℃ for 12-24 hours. In step S2, the impregnation temperature is room temperature and the impregnation time is 2 to 4 hours; then the drying process is carried out at a temperature of 80 to 150°C and a drying time of 8 to 16 hours.

8. The method for preparing the supported catalyst according to claim 3, characterized in that, In step S2, during the roasting process, the roasting atmosphere is air, the roasting temperature is 400-800℃, and the roasting time is 3-8h.

9. An application of the supported catalyst as described in claim 1 or 2, characterized in that, This catalyst is used for the catalytic reaction of synthesizing methyl glyoxylate from methyl glycolate.

10. The application of the supported catalyst according to claim 9, characterized in that, In the catalytic reaction, the reaction temperature is 160–320℃, the reaction pressure is 0.05–1.5 MPa, the molar ratio of methyl glycolate to oxygen is 1:(0.5–20), and the liquid hourly space velocity of methyl glycolate is 0.1–2.5 h⁻¹. -1 .

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