Catalyst and Preparation Method for Hydrogenation of Dimethyl Maleate to 1,4-Butanediol

Abstract

This invention discloses a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising: using deionized water as a base liquid, sequentially precipitating an auxiliary metal, a support, and an active metal; aging, washing, drying, calcining, and molding the precipitated material into a Raschig ring to obtain the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol; wherein the auxiliary metal is Mn, Zn, Mg, or Zr, and the active metal is Cu. The catalyst prepared by the above method achieves a maximum conversion rate of 99.9%, a maximum selectivity of 95.8%, and a maximum yield of 95.8% in the catalytic reaction of hydrogenating dimethyl maleate to 1,4-butanediol.

Description

Technical Field

[0001] This invention belongs to the field of catalytic technology, specifically relating to a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol and its preparation method. Background Technology

[0002] In modern chemical industry, 1,4-butanediol (1,4-BDO) is a major fine chemical product. High-value-added downstream chemicals produced from it, such as tetrahydrofuran (THF) and γ-butyrolactone (GBL), are widely used in polyester materials, papermaking, pharmaceuticals, automobiles, pesticides, textiles, and daily necessities. It is also a basic raw material for the industrial production of high-value chemicals such as polybutylene adipate (PBAT), polybutylene succinate (PBS), and polybutylene terephthalate (PBT). PBT plastic is considered one of the five most promising engineering plastics, while PBS plastic is biodegradable. In recent years, due to the implementation of the "plastic restriction order" and the rapid development of other sectors, the market demand for 1,4-butanediol has been continuously increasing. Therefore, designing and preparing a highly efficient and green catalytic process for the production of 1,4-butanediol is imperative.

[0003] Currently, there are four main industrial methods for producing 1,4-butanediol: the acetylene-aldehyde method, the butadiene-acetylene oxygenation method, the allyl alcohol method, and the maleic anhydride hydrogenation method. Among these, the acetylene-aldehyde method is limited due to rising acetylene prices and low safety; the butadiene-acetylene oxygenation method lacks competitiveness due to poor catalyst stability and high infrastructure investment; the allyl alcohol method is constrained by high production costs and complex processes; and the maleic anhydride hydrogenation method is not widely used due to numerous reaction byproducts and poor selectivity.

[0004] Patent application CN 116514636 A discloses a method for preparing 1,4-butanediol, using dimethyl maleate as a raw material, Cu-Al-M as a catalyst (M being an alkali metal such as Mn, Zr, Co, or Mg), and 1,4-dioxane as a solvent, through a two-step hydrogenation process. Compared to traditional isothermal hydrogenation, the two-step hydrogenation method, by changing the temperature of the two stages, better adapts to the characteristics of each stage of the reaction, achieving a yield of 91%. However, the reaction must be carried out under high-pressure hydrogen gas at 6 MPa, and the reaction vessel is a high-pressure reactor, making continuous production impossible.

[0005] Patent application CN 114685242 B discloses a one-step liquid-phase hydrogenation method for producing 1,4-butanediol from dimethyl maleate. The method includes the following steps: adding dimethyl maleate, a catalyst, and dioxane solvent to a high-pressure reactor, sealing the reactor, and purging it with hydrogen gas to a pressure of 5–7 MPa. The reactor is then stirred and reacted at 140–220 °C for 7–12 hours to obtain 1,4-butanediol. The catalyst is a copper-zinc-magnesium catalyst or a copper-zinc-silicon catalyst modified with a silanizing agent. This invention can obtain a high yield of 1,4-butanediol under temperature and pressure conditions comparable to or milder than gas-phase hydrogenation, exceeding the results of most previous hydrogenation methods, and saving the heat required for raw material gasification and the amount of hydrogen consumed. However, the key challenges to overcome in this invention lie in the introduction of ammonia-containing additives and the use of toxic organic solvents.

[0006] Based on the above, it can be seen that the existing process can no longer fully meet the growing needs of 1,4-butanediol industrial production. A preparation process for CuMnAl catalyst that can meet the current requirements for catalyst selectivity, cost, and other factors is needed. Summary of the Invention

[0007] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol and its preparation method. This method involves first preparing a precipitate system containing an auxiliary metal element, then preparing a precipitate system containing an auxiliary metal and a support, and then preparing a precipitate system containing an active metal, an auxiliary metal, and a support. Subsequently, the precipitate system containing the active metal, the auxiliary metal, and the support is aged, dried, calcined, and shaped to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst prepared by the above method achieves a conversion rate of up to 99.9%, a selectivity of up to 95.8%, and a yield of up to 95.8% in the catalytic reaction of hydrogenating dimethyl maleate to 1,4-butanediol.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, characterized in that it includes: using deionized water as the base liquid, sequentially precipitating an auxiliary metal, a support, and an active metal; aging, washing, drying, calcining, and molding the precipitated material into a Raschig ring to obtain the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol; wherein the auxiliary metal is Mn, Zn, Mg, or Zr, and the active metal is Cu.

[0009] The above-mentioned method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol is characterized by the following specific steps: using deionized water as the base liquid, the method of sequentially precipitating the auxiliary metal, the support, and the active metal includes:

[0010] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0011] Under room temperature stirring conditions, a soluble salt solution of the auxiliary metal element was added dropwise to deionized water while the pH of the system was controlled within a preset range. After the addition was completed, stirring was continued to ensure complete precipitation, resulting in a precipitation system containing the auxiliary metal element.

[0012] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0013] Step 201: Dissolve the aluminum source in deionized water to obtain an aluminum source solution;

[0014] Step 202: Under stirring conditions, the aluminum source solution is added dropwise to the precipitation system containing the auxiliary metal element. The pH value of the system is controlled to be 6.5-7. After the addition is completed, stirring is continued to ensure complete precipitation, thereby obtaining a precipitation system containing the auxiliary metal and the carrier.

[0015] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0016] Step 301: Dissolve the copper source in deionized water to obtain a copper source solution;

[0017] Step 302: Under stirring conditions, the copper source solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier. The pH value of the system is controlled to be 6-6.5. After the addition is complete, stirring is continued to ensure complete precipitation, thereby obtaining a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0018] The method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol is characterized in that, in step one, the dropping rate of the soluble salt solution of the auxiliary metal element into deionized water is 20-50 mL / min.

[0019] The method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol is characterized in that, in step one, the auxiliary metal element is Mn, Zn, Mg or Zr; when the auxiliary metal element is Mn, the pH range is 9.5-10; when the auxiliary metal element is Zn or Zr, the pH range is 7-7.5; and when the auxiliary metal element is Mg, the pH range is 9-9.5.

[0020] The method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol is characterized in that the auxiliary metal element is Mn.

[0021] The method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol is characterized in that the aging temperature is 60°C and the aging time is 16 hours.

[0022] The method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol is characterized in that the washing is performed with deionized water until the conductivity of the filtrate is below 100 μs / cm; the drying temperature is 80°C and the drying time is 18 h; and the calcination temperature is 550°C and the calcination time is 4 h.

[0023] The method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol is characterized in that the method of forming a Raschig ring specifically includes: mixing graphite with calcined material to obtain a material mixed with a release agent, and pressing the material mixed with the release agent into tablets to obtain a Raschig ring; wherein the mass percentage of graphite in the material mixed with the release agent is 2%.

[0024] Furthermore, the present invention also provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol prepared according to the above-described method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, characterized in that the catalyst is a CuAlM catalyst, wherein M is Mn, Zn, Mg or Zr, and the mass ratio of Cu:Al:M in the catalyst is (40-60):(20-50):(10-20).

[0025] The catalyst described above is characterized in that M is Mn, and the mass ratio of Cu:Al:Mn in the catalyst is 50:35:15.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. In the preparation method of the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol of the present invention, a precipitate system containing an auxiliary metal element is first prepared, then a precipitate system containing an auxiliary metal and a support is prepared, and then a precipitate system containing an active metal, an auxiliary metal, and a support is prepared. Subsequently, the precipitate system containing the active metal, the auxiliary metal, and the support is aged, dried, calcined, and shaped to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst prepared by the above method can achieve a conversion rate of up to 99.9%, a selectivity of up to 95.8%, and a yield of up to 95.8% in the catalytic reaction of hydrogenation of dimethyl maleate to 1,4-butanediol.

[0028] 2. In the preparation method of the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol of the present invention, the problems of incomplete precipitation or excessive waste liquid caused by the large difference in precipitation pH of the catalyst components are solved by the sequential precipitation of the auxiliary metal, support and active components. It has the characteristics of high catalytic performance and low post-treatment cost.

[0029] 3. In the preparation method of the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol of the present invention, the sequential precipitation of the auxiliary metal, the support and the active component is carried out by adding the corresponding soluble metal salt solution at room temperature, and combined with static aging under heating conditions, which can effectively improve the bulk density of the catalyst.

[0030] 4. The preparation method of the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol of the present invention includes shaping the catalyst into a Raschig ring, which can effectively increase the contact area between the catalyst and the reactants, reduce the reaction pressure drop, and reduce the loss of active components.

[0031] 5. In the preparation method of the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol of the present invention, graphite is added as a release agent when the catalyst is shaped into a Raschig ring, which has the characteristic of more stable molding.

[0032] 6. The catalyst prepared by the method of the present invention is suitable for fixed-bed reactors, has the characteristics of stable continuous production performance, can effectively improve industrial capacity, and is suitable for industrial promotion and application.

[0033] 7. The method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol of the present invention solves the problems of poor selectivity, high production cost, large environmental impact, and harsh preparation or reaction conditions of current catalysts used for the hydrogenation of dimethyl maleate to 1,4-butanediol. It provides a new approach for the preparation of catalysts and process improvement for the hydrogenation of dimethyl maleate to 1,4-butanediol.

[0034] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0035] Instruction manual illustrations

[0036] Figure 1 This is a transmission electron microscope (TEM) image of the catalyst from Example 1.

[0037] Figure 2 This is a scanning electron microscope image of the catalyst from Example 1. Detailed Implementation

[0038] Example 1

[0039] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlMn catalyst, and the mass ratio of Cu:Al:Mn in the catalyst is 50:35:15.

[0040] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0041] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0042] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; dilute 195g of 50% manganese nitrate solution to 500mL with deionized water to prepare a manganese source solution.

[0043] Step 102: Under stirring conditions of 300 r / min, the manganese source solution is added dropwise to system A at a dropping rate of 20 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 9.5-10. After the dropping is completed, stirring is continued for 30 minutes to allow Mn to precipitate completely, thus obtaining a precipitation system containing auxiliary metal elements.

[0044] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0045] Step 201: Dissolve 972g of aluminum nitrate nonahydrate in deionized water and bring the volume to 1.5L to obtain an aluminum nitrate solution;

[0046] Step 202: Under stirring conditions of 300 r / min, the aluminum nitrate solution is added dropwise to the precipitation system containing the auxiliary metal element at a dropping rate of 50 mL / min. At the same time, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6.5-7. After the addition is completed, stirring is continued for 30 minutes to allow Al to precipitate completely, thus obtaining a precipitation system containing the auxiliary metal and the carrier.

[0047] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0048] Step 301: Dissolve 378g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0049] Step 302: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the addition is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0050] Step 4: Provide catalyst precursors, specifically including:

[0051] Step 401: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0052] Step 402: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0053] Step 5: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0054] Step Six: Graphite is mixed into the calcined material as a release agent to obtain a material mixed with the release agent. The material mixed with the release agent is then pressed into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as Cu. 0.5 Mn 0.15 Al 0.35 The graphite content in the material containing the release agent is 2% by mass.

[0055] Example 2

[0056] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlMn catalyst, and the mass ratio of Cu:Al:Mn in the catalyst is 40:50:10.

[0057] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0058] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0059] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; dilute 130g of 50% manganese nitrate solution to 500mL with deionized water to prepare a manganese source solution.

[0060] Step 102: Under stirring conditions of 300 r / min, the manganese source solution is added dropwise to system A at a dropping rate of 20 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 9.5-10. After the dropping is completed, stirring is continued for 30 minutes to allow Mn to precipitate completely, thus obtaining a precipitation system containing auxiliary metal elements.

[0061] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0062] Step 201: Dissolve 1389g of aluminum nitrate nonahydrate in deionized water and bring the volume to 1.5L to obtain an aluminum nitrate solution;

[0063] Step 202: Under stirring conditions of 300 r / min, the aluminum nitrate solution is added dropwise to the precipitation system containing the auxiliary metal element at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6.5-7. After the dropping is completed, stirring is continued for 30 minutes to allow Al to precipitate completely, thus obtaining a precipitation system containing the auxiliary metal and the carrier.

[0064] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0065] Step 301: Dissolve 302g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0066] Step 302: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0067] Step 4: Provide catalyst precursors, specifically including:

[0068] Step 401: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0069] Step 402: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0070] Step 5: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0071] Step Six: Graphite is mixed into the calcined material as a release agent to obtain a material mixed with the release agent. The material mixed with the release agent is then pressed into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as Cu. 0.4 Mn 0.1 Al 0.5 The graphite content in the material containing the release agent is 2% by mass.

[0072] Example 3

[0073] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlMn catalyst, and the mass ratio of Cu:Al:Mn in the catalyst is 60:20:20.

[0074] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0075] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0076] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; dilute 260g of 50% manganese nitrate solution to 500mL with deionized water to prepare a manganese source solution.

[0077] Step 102: Under stirring conditions of 300 r / min, the manganese source solution is added dropwise to system A at a dropping rate of 20 mL / min. At the same time, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 9.5-10. After the manganese nitrate solution is added, stirring is continued for 30 minutes to allow Mn to precipitate completely, thus obtaining a precipitation system containing auxiliary metal elements.

[0078] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0079] Step 201: Dissolve 556g of aluminum nitrate nonahydrate in deionized water and bring the volume to 1.5L to obtain an aluminum nitrate solution;

[0080] Step 202: Under stirring conditions of 300 r / min, the aluminum nitrate solution is added dropwise to the precipitation system containing the auxiliary metal element at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6.5-7. After the dropping is completed, stirring is continued for 30 minutes to allow Al to precipitate completely, thus obtaining a precipitation system containing the auxiliary metal and the carrier.

[0081] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0082] Step 301: Dissolve 453g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0083] Step 302: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0084] Step 4: Provide catalyst precursors, specifically including:

[0085] Step 401: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0086] Step 402: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0087] Step 5: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0088] Step Six: Graphite is mixed into the calcined material as a release agent to obtain a material mixed with the release agent. The material mixed with the release agent is then pressed into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as Cu. 0.6 Mn 0.2 Al 0.2 The graphite content in the material containing the release agent is 2% by mass.

[0089] Example 4

[0090] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlMn catalyst, and the mass ratio of Cu:Al:Mn in the catalyst is 50:35:15.

[0091] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0092] Step 1: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0093] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; mix 195g of 50% manganese nitrate solution, 972g of aluminum nitrate nonahydrate and 378g of copper nitrate trihydrate, and make up to 3.5L with deionized water to prepare a salt mixture solution.

[0094] Step 102: Under stirring conditions of 300 r / min, the salt mixture solution is added dropwise to system A at a dropping rate of 50 mL / min. At the same time as the dropwise addition, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 9.5-10. After the salt mixture solution is completely added, stirring is continued for 120 minutes to allow all components to precipitate completely, resulting in a precipitation system containing active metal, auxiliary metal and carrier.

[0095] Step 2: Provide catalyst precursors, specifically including:

[0096] Step 201: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0097] Step 202: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0098] Step 3: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0099] Step 4: Graphite is mixed into the calcined material as a release agent to obtain a material mixed with the release agent. The material mixed with the release agent is then pressed into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as CuMnAl. one-step The graphite content in the material containing the release agent is 2% by mass.

[0100] Example 5

[0101] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlMn catalyst, and the mass ratio of Cu:Al:Mn in the catalyst is 50:35:15.

[0102] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0103] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0104] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; dilute 195g of 50% manganese nitrate solution to 500mL with deionized water to prepare a manganese source solution.

[0105] Step 102: Under stirring conditions of 300 r / min, the manganese source solution is added dropwise to system A at a dropping rate of 20 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 9.5-10. After the dropping is completed, stirring is continued for 30 minutes to allow Mn to precipitate completely, thus obtaining a precipitation system containing auxiliary metal elements.

[0106] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0107] Step 201: Dissolve 972g of aluminum nitrate nonahydrate in deionized water and bring the volume to 1.5L to obtain an aluminum nitrate solution;

[0108] Step 202: Under stirring conditions of 300 r / min, the aluminum nitrate solution is added dropwise to the precipitation system containing the auxiliary metal element at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6.5-7. After the dropping is completed, stirring is continued for 30 minutes to allow Al to precipitate completely, thus obtaining a precipitation system containing the auxiliary metal and the carrier.

[0109] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0110] Step 301: Dissolve 378g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0111] Step 302: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0112] Step 4: Provide catalyst precursors, specifically including:

[0113] Step 401: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0114] Step 402: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0115] Step 5: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0116] Step Six: Graphite is mixed into the calcined material as a release agent to obtain a material mixed with the release agent. This material is then pressed into solid cylinders of 3mm x 3mm to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as CuMnAl. 实柱 The graphite content in the material containing the release agent is 2% by mass.

[0117] Example 6

[0118] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlZn catalyst, and the mass ratio of Cu:Al:Zn in the catalyst is 50:35:15.

[0119] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0120] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0121] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; dissolve 137g of zinc nitrate hexahydrate in deionized water and make up to 500mL to prepare a zinc nitrate solution.

[0122] Step 102: Under stirring conditions of 300 r / min, the zinc nitrate solution is added dropwise to system A at a dropping rate of 20 mL / min. At the same time as the dropwise addition, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 7-7.5. After the dropwise addition is completed, stirring is continued for 30 minutes to allow Zn to precipitate completely, thus obtaining a precipitation system containing auxiliary metal elements.

[0123] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0124] Step 201: Dissolve 972g of aluminum nitrate nonahydrate in deionized water and bring the volume to 1.5L to obtain an aluminum nitrate solution;

[0125] Step 202: Under stirring conditions of 300 r / min, the aluminum nitrate solution is added dropwise to the precipitation system containing the auxiliary metal element at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6.5-7. After the dropping is completed, stirring is continued for 30 minutes to allow Al to precipitate completely, thus obtaining a precipitation system containing the auxiliary metal and the carrier.

[0126] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0127] Step 301: Dissolve 378g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0128] Step 302: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0129] Step 4: Provide catalyst precursors, specifically including:

[0130] Step 401: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0131] Step 402: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0132] Step 5: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0133] Step 6: Add graphite as a release agent to the calcined material to obtain a material mixed with the release agent. Compress the material mixed with the release agent into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as CuZnAl. The mass percentage of graphite in the material mixed with the release agent is 2%.

[0134] Example 7

[0135] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlMg catalyst, and the mass ratio of Cu:Al:Mg in the catalyst is 50:35:15.

[0136] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0137] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0138] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; dissolve 320g of magnesium nitrate hexahydrate in deionized water and make up to 500mL to prepare magnesium nitrate solution.

[0139] Step 102: Under stirring conditions of 300 r / min, the magnesium nitrate solution is added dropwise to system A at a dropping rate of 20 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 9-9.5. After the dropping is completed, stirring is continued for 30 minutes to allow Mg to precipitate completely, thus obtaining a precipitation system containing auxiliary metal elements.

[0140] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0141] Step 201: Dissolve 972g of aluminum nitrate nonahydrate in deionized water and bring the volume to 1.5L to obtain an aluminum nitrate solution;

[0142] Step 202: Under stirring conditions of 300 r / min, the aluminum nitrate solution is added dropwise to the precipitation system containing the auxiliary metal element at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6.5-7. After the dropping is completed, stirring is continued for 30 minutes to allow Al to precipitate completely, thus obtaining a precipitation system containing the auxiliary metal and the carrier.

[0143] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0144] Step 301: Dissolve 378g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0145] Step 302: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0146] Step 4: Provide catalyst precursors, specifically including:

[0147] Step 401: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0148] Step 402: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0149] Step 5: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0150] Step 6: Add graphite as a release agent to the calcined material to obtain a material mixed with the release agent. Compress the material mixed with the release agent into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as CuMgAl. The mass percentage of graphite in the material mixed with the release agent is 2%.

[0151] Example 8

[0152] This embodiment provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is a CuAlZr catalyst, and the mass ratio of Cu:Al:Zr in the catalyst is 50:35:15.

[0153] This embodiment provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0154] Step 1: Provide a precipitation system containing auxiliary metal elements, specifically including:

[0155] Step 101: At room temperature, add 1L of deionized water to the reactor as the base liquid to obtain system A; dissolve 136g of zirconium nitrate pentahydrate in deionized water and make up to 500mL to prepare zirconium nitrate solution.

[0156] Step 102: Under stirring conditions of 300 r / min, the zirconium nitrate solution is added dropwise to system A at a dropping rate of 20 mL / min. At the same time as the dropwise addition, a sodium carbonate solution with a mass percentage of 10% is added dropwise to the reactor to control the pH value of the system to 7-7.5. After the dropwise addition is completed, stirring is continued for 30 minutes to allow Zr to precipitate completely, thus obtaining a precipitation system containing auxiliary metal elements.

[0157] Step 2: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0158] Step 201: Dissolve 972g of aluminum nitrate nonahydrate in deionized water and bring the volume to 1.5L to obtain an aluminum nitrate solution;

[0159] Step 202: Under stirring conditions of 300 r / min, the aluminum nitrate solution is added dropwise to the precipitation system containing the auxiliary metal element at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6.5-7. After the dropping is completed, stirring is continued for 30 minutes to allow Al to precipitate completely, thus obtaining a precipitation system containing the auxiliary metal and the carrier.

[0160] Step 3: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0161] Step 301: Dissolve 378g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0162] Step 302: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0163] Step 4: Provide catalyst precursors, specifically including:

[0164] Step 401: Heat the precipitation system containing the active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours;

[0165] Step 402: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0166] Step 5: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0167] Step 6: Add graphite as a release agent to the calcined material to obtain a material mixed with the release agent. Compress the material mixed with the release agent into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as CuZrAl. The mass percentage of graphite in the material mixed with the release agent is 2%.

[0168] Comparative Example 1

[0169] This comparative example provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is composed of an active component, a support, and a co-active component. The support is SiO2, and the co-active component is Mn. In the catalyst, the active component Cu has a mass percentage of 50%, the support SiO2 has a mass percentage of 35%, and the co-active component Mn has a mass percentage of 15%.

[0170] This comparative example provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0171] Step 1: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0172] Step 101: At room temperature, dissolve 70g of SiO2 powder in deionized water and bring the volume to 1L to obtain a suspension. Pour the obtained suspension into a reaction vessel. Bring 195g of 50% manganese nitrate solution to 500mL with deionized water to prepare a manganese source solution.

[0173] In step 102, under stirring conditions of 300 r / min, the manganese source solution is added dropwise to the suspension at a dropping rate of 20 mL / min. At the same time as the dropwise addition, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 9.5-10. After the dropwise addition is completed, stirring is continued for 30 minutes to allow Mn to precipitate completely, resulting in a precipitation system containing auxiliary metals and a carrier.

[0174] Step 2: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0175] Step 201: Dissolve 378g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0176] Step 202: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, thus obtaining a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0177] Step 3: Provide catalyst precursors, specifically including:

[0178] Step 301: Heat the precipitation system containing active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours.

[0179] Step 302: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0180] Step 4: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0181] Step 5: Graphite is mixed into the calcined material as a release agent to obtain a material mixed with the release agent. The material mixed with the release agent is pressed into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as CuMnSi. The mass percentage of graphite in the material mixed with the release agent is 2%.

[0182] Comparative Example 2

[0183] This comparative example provides a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol. The catalyst is composed of an active component, a support, and a co-active component. The support is TiO2, and the co-active component is Mn. In the catalyst, the active component Cu has a mass percentage of 50%, the support TiO2 has a mass percentage of 35%, and the co-active component Mn has a mass percentage of 15%.

[0184] This comparative example provides a method for preparing a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, comprising:

[0185] Step 1: Provide a precipitation system containing auxiliary metals and a carrier, specifically including:

[0186] Step 101: At room temperature, dissolve 70g of TiO2 powder in deionized water and bring the volume to 1L to obtain a suspension. Pour the suspension into a reaction vessel. Prepare a manganese source solution by bringing the volume of 195g of 50% manganese nitrate solution to 500mL with deionized water.

[0187] Step 102: Under stirring conditions of 300 r / min, the manganese source solution is added dropwise to the suspension at a dropping rate of 20 mL / min. At the same time as the dropwise addition, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 9.5-10. After the dropwise addition is completed, stirring is continued for 30 minutes to allow Mn to precipitate completely, thus obtaining a precipitation system containing auxiliary metals and a carrier.

[0188] Step 2: Provide a precipitation system containing an active metal, an auxiliary metal, and a carrier, specifically including:

[0189] Step 201: Dissolve 378g of copper nitrate trihydrate in deionized water and bring the volume to 1.5L to obtain a copper nitrate solution;

[0190] Step 202: Under stirring conditions of 300 r / min, the copper nitrate solution is added dropwise to the precipitation system containing the auxiliary metal and the carrier at a dropping rate of 50 mL / min. At the same time as the dropping, a sodium carbonate solution with a mass percentage of 10% is added dropwise to control the pH value of the system to 6-6.5. After the dropping is completed, stirring is continued for 120 minutes to allow Cu to precipitate completely, resulting in a precipitation system containing the active metal, the auxiliary metal and the carrier.

[0191] Step 3: Provide catalyst precursors, specifically including:

[0192] Step 301: Heat the precipitation system containing active metal, auxiliary metal and carrier to 60°C and maintain it for static aging for 16 hours.

[0193] Step 302: Remove the supernatant, filter the suspension while it is hot, wash with deionized water until the conductivity of the filtrate is below 100 μs / cm, wash three times with anhydrous ethanol, and dry in an oven at 80°C for 18 h to obtain the catalyst precursor.

[0194] Step 4: Crush and sieve the catalyst precursor into powder of less than 30 mesh, and calcine it in a muffle furnace at a heating rate of 5°C per minute to 550°C and maintain it for 4 hours to obtain the calcined material.

[0195] Step 5: Add graphite as a release agent to the calcined material to obtain a material mixed with the release agent. Compress the material mixed with the release agent into 3mm*3mm Raschig rings to obtain a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, denoted as CuMnTi. The mass percentage of graphite in the material mixed with the release agent is 2%.

[0196] Comparative Example 3

[0197] This comparative example provides a method for preparing a catalyst, which is based on patent application CN113332999B and specifically includes:

[0198] Step 1: Dissolve 29.5g of copper nitrate in deionized water, add 74.5g of aluminum oxide, impregnate for 1 hour under nitrogen protection, rotate and heat to evaporate the water, and then calcine at 550℃ in a nitrogen atmosphere for 4 hours to obtain supported catalyst precursor A, for later use.

[0199] Step 2: Dissolve 29.0g of zinc nitrate in deionized water to obtain a zinc nitrate solution. Add the supported catalyst precursor A to the zinc nitrate solution and impregnate it for 1 hour under nitrogen protection. Then, use rotary heating to evaporate the water and calcine it at 550°C in a nitrogen atmosphere for 4 hours to obtain the supported catalyst precursor B for later use.

[0200] Step 3: Dissolve 11.6g of cerium nitrate in deionized water to obtain a cerium nitrate solution. Add the supported catalyst precursor B to the cerium nitrate solution and impregnate it for 1 hour under nitrogen protection. Then, use rotary heating to evaporate the water and calcine it in a nitrogen atmosphere at 400°C for 2 hours to obtain the supported catalyst precursor C for later use.

[0201] Step 4: Dissolve 0.83g of palladium chloride in deionized water to obtain an aqueous solution of palladium chloride. Add 8g of polyvinylpyrrolidone and 200ml of anhydrous ethanol, mix for 20min, then add 200ml of reducing agent formaldehyde, and stir the reduction reaction at 80℃ for 2h to obtain a mixed solution for later use.

[0202] Step 5: Add the supported catalyst precursor C to the mixed solution, let it stand for 8 hours, filter and wash, dry it under a nitrogen atmosphere, and calcine it at 300°C under a nitrogen atmosphere for 2 hours to obtain the catalyst, denoted as DB-1.

[0203] Comparative Example 4

[0204] This comparative example provides a method for preparing a catalyst, which is based on patent application CN 115043708A, and specifically includes:

[0205] Step 1: Dissolve 1g of polyoxyethylene polyoxypropylene ether block copolymer F127 and 0.5g of dopamine in a mixture of 100mL of water and anhydrous ethanol, and slowly inject 2mL of mesitylene to obtain a nanoemulsion system; the volume ratio of water to anhydrous ethanol in the mixture of water and anhydrous ethanol is 1:1.

[0206] Step 2: At room temperature, the nanoemulsion system was continuously stirred for 30 min, and 5.0 mL of ammonia water was added dropwise to induce dopamine to undergo self-polymerization for 12 h. After filtration, a black solid phase was obtained.

[0207] Step 3: Under an argon atmosphere, the black solid phase is heated to 800°C at a heating rate of 1°C / min and held for 2 hours to obtain the HPNC support.

[0208] Step 4: Mix 150 mg of hierarchical porous nitrogen-doped carbon nanospheres (HPNC) with 530 mg of (CO). 12 Ru3 was added to 40 mL of acetone and ultrasonically dispersed for 30 min to obtain the ultrasonicated system.

[0209] Step 5: Stir at room temperature for 4 hours, remove solvent by rotary evaporation, dry, and calcine and reduce in a tube furnace at 200℃-400℃ for 2 hours under H2 / Ar atmosphere to obtain the catalyst, denoted as DB-2.

[0210] Application Evaluation Example

[0211] This application example provides a method for evaluating the performance of Examples 1-8 and Comparative Examples 1-4, specifically including:

[0212] Step 1: Take 4g of the above catalyst and load it into a fixed-bed tubular reactor. In a hydrogen atmosphere, heat the reactor to 250℃ at a heating rate of 1℃ / min and maintain the temperature for 2 hours for reduction.

[0213] Step 2: Prepare a methanol solution of dimethyl maleate with a mass fraction of 15%;

[0214] Step 3: Hydrogen gas and a methanol solution of dimethyl maleate are introduced into the fixed-bed tubular reactor for reaction; wherein the hydrogen-to-ester ratio is 60 and the liquid hourly space velocity is 1 g / g·cat·h. -1 The reaction temperature was 180℃, the reaction pressure was 5MPa, and the running time was 800h. The product was analyzed using a GC-2060 gas chromatograph. The experimental results are shown in Table 1.

[0215] Table 1 Catalytic performance results of the catalyst

[0216]

[0217]

[0218] As can be seen from Table 1, when comparing Example 1 with Comparative Examples 1-4, the catalyst of Example 1 has the best catalytic activity and higher cost performance.

[0219] Furthermore, compared to the catalyst prepared by the one-step precipitation-deposition method (Example 4), the catalyst prepared by the stepwise precipitation-deposition method of the present invention has higher catalytic performance, complete precipitation of the system, and less waste liquid and waste material. Moreover, compared with solid column molding, the catalyst prepared by the Raschig ring molding method has better catalytic performance in the hydrogenation of dimethyl maleate to 1,4-butanediol.

[0220] The results also showed that different co-active components (Zn, Mg, Zr) and different supports (SiO2, TiO2) were inferior to CuMnAl catalysts in the catalytic hydrogenation of dimethyl maleate to 1,4-butanediol. In CuMnAl catalysts, when the mass ratio of Cu:Al:Mn was 50:35:15, the conversion rate reached 99.9%, the selectivity reached 95.8%, and the yield reached 95.8%, demonstrating higher catalytic performance.

[0221] The catalyst described in Example 1 was continuously operated for 800 hours according to the above performance evaluation method for a lifetime test. The test results showed that after 800 hours of operation, the conversion rate, selectivity and yield of the catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol remained at 98%, 94% and 92%, respectively, indicating that the catalyst of the present invention has a stable lifetime.

[0222] according to Figure 1 and Figure 2 It is known that the catalyst prepared by the method of the present invention uses sheet-like alumina as a support, on which clusters of bimetallic spheres are uniformly supported.

[0223] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the invention shall still fall within the protection scope of the present invention.

Claims

1. A process for the preparation of a catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, characterized in that, The application relates to a CuAlM catalyst for hydrogenating dimethyl maleate into 1,4-butanediol. The method comprises the following steps: In step one, the soluble salt solution of the auxiliary metal element is dropped into deionized water under stirring at room temperature, and the pH value of the system is controlled in a preset range during dropping; after dropping is completed, stirring is continued to make the precipitation complete, and the precipitation system containing the auxiliary metal element is obtained. In step two, the precipitation system containing the auxiliary metal and the carrier is provided, and the method comprises the following steps: In step 201, an aluminum source is dissolved in deionized water to obtain an aluminum source solution; In step 202, the aluminum source solution is dropped into the precipitation system containing the auxiliary metal element under stirring, the pH value of the system is controlled to be 6.5-7, and after dropping is completed, stirring is continued to make the precipitation complete, and the precipitation system containing the auxiliary metal and the carrier is obtained. In step three, the precipitation system containing the active metal, the auxiliary metal and the carrier is provided, and the method comprises the following steps: In step 301, a copper source is dissolved in deionized water to obtain a copper source solution; In step 302, the copper source solution is dropped into the precipitation system containing the auxiliary metal and the carrier under stirring, the pH value of the system is controlled to be 6-6.5, and after dropping is completed, stirring is continued to make the precipitation complete, and the precipitation system containing the active metal, the auxiliary metal and the carrier is obtained. In step one, the dropping speed of the soluble salt solution of the auxiliary metal element into deionized water is 20-50 mL / min.

2. The process for preparing a catalyst for hydrogenation of dimethyl maleate to 1,4-butanediol according to claim 1, characterized in that, In step one, the auxiliary metal element is Mn, Zn, Mg or Zr; when the auxiliary metal element is Mn, the preset pH value is 9.5-10; when the auxiliary metal element is Zn or Zr, the preset pH value is 7-7.5; and when the auxiliary metal element is Mg, the preset pH value is 9-9.

5.

3. The process for preparing a catalyst for hydrogenation of dimethyl maleate to 1,4-butanediol according to claim 1, characterized in that, The auxiliary metal element is Mn.

4. The process for preparing a catalyst for hydrogenation of dimethyl maleate to 1,4-butanediol according to claim 3, characterized by, The aging temperature is 60 DEG C, and the aging time is 16 h.

5. The process for preparing a catalyst for hydrogenation of dimethyl maleate to 1,4-butanediol according to claim 1, characterized by, The washing is washing with deionized water until the conductivity of the filtrate is below 100 mu S / cm; the drying temperature is 80 DEG C, and the drying time is 18 h; and the calcination temperature is 550 DEG C, and the calcination time is 4 h.

6. The process for preparing a catalyst for hydrogenation of dimethyl maleate to 1,4-butanediol according to claim 1, characterized by, The forming method of the Lacey ring type comprises the following steps that the graphite is mixed with the calcined material to obtain material mixed with a release agent, and the material mixed with the release agent is pressed to obtain the Lacey ring type; and in the material mixed with the release agent, the mass percentage of the graphite is 2%.

7. The process for preparing a catalyst for hydrogenation of dimethyl maleate to 1,4-butanediol according to claim 1, characterized by, The catalyst is a CuAlM catalyst, M is Mn, Zn, Mg or Zr, and the mass ratio of Cu:Al:M in the catalyst is (40-60):(20-50):(10-20).

8. A catalyst for the hydrogenation of dimethyl maleate to 1,4-butanediol, which is prepared by the process according to any one of claims 1 to 7, characterized in that M is Mn, and the mass ratio of Cu:Al:Mn in the catalyst is 50:35:

15.

9. The catalyst of claim 8, wherein ​

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