Dimethyl maleate hydrogenation catalyst as well as preparation method and application thereof

Abstract

The invention discloses a dimethyl maleate hydrogenation catalyst precursor, a hydrogenation catalyst and a preparation method and application thereof. The precursor comprises a biological template and a copper-zinc bimetal organic framework material, and the preparation method comprises the following steps: (1) mixing a copper source solution with the biological template, controlling the concentration of the biological template in the mixed solution, stirring under a heating condition, then filtering, separating and collecting a precipitate; (2) mixing the precipitate obtained in the step (1) with an organic ligand solution, reacting, separating, washing and drying to obtain a dry solid; and (3) mixing a zinc source solution with the dried solid obtained in the step (2), reacting, separating, washing and drying to obtain the catalyst precursor. When the catalyst is applied to dimethyl maleate hydrogenation, the catalyst is high in activity, good in selectivity and suitable for co-production of BDO, THF and GBL through dimethyl maleate hydrogenation.

Description

Technical Field

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

[0002] 1,4-Butanediol (BDO) is an important organic chemical and fine chemical raw material, which is widely used in the fields of medicine, daily chemical, textile, papermaking, etc. BDO has many downstream derivatives such as γ-butyrolactone (GBL), polybutylene terephthalate (PBT), tetrahydrofuran (THF), polyurethane, coatings and plasticizers, among which THF can be polycondensed with BDO to form polytetramethylene ether (PTMG) and polycondensed by itself to form polytetramethylene ether glycol (PTMEG); GBL is a fine chemical product and a widely used chemical intermediate in industrial fields such as petrochemicals, medicine, textiles, spices and pesticides. It can be used as an excellent high-boiling point extractant and absorbent, has good reaction performance, can undergo a series of ring-opening and non-ring-opening chemical reactions, and is an important raw material for the synthesis of pyrrolidone and cyclopropylamine compounds. In recent years, due to the rapid growth of market demand for thermoplastic elastic fibers and elastomers, the demand for polytetramethylene ether glycol (PTMEG) and polytetramethylene ether (PTMG) as monomers has become more vigorous. Therefore, based on the huge demand for high value-added chemical products in the BDO industry chain, it is of great significance to develop technology for co-producing BDO and GBL and THF.

[0003] At present, the preparation routes of 1,4-butanediol mainly include: 1. Reppe method (acetylene aldehyde method) using formaldehyde and acetylene (acetylene carbide) as raw materials; 2. Butadiene acetoxylation method using butadiene and acetic acid as raw materials; 3. Propylene oxide method using propylene oxide / propylene alcohol as raw materials; 4. Maleic anhydride method using n-butane / maleic anhydride as raw materials. Maleic anhydride method is mainly selected as the process route for co-production of 1,4-butanediol, γ-butyrolactone and tetrahydrofuran in industry, that is, maleic anhydride or maleic acid dialkyl ester (such as dimethyl maleate) is hydrogenated in gas / liquid phase to produce γ-butyrolactone and tetrahydrofuran while producing 1,4-butanediol, and the catalyst mainly uses copper catalyst.

[0004] CN103551154A discloses a method for preparing a dimethyl maleate hydrogenation catalyst. The catalyst preparation method comprises preparing a catalyst precursor by mixing a coprecipitated material of copper and zinc with a pseudo-boehmite sol, drying and calcining, and then mixing with pseudo-boehmite powder to obtain a catalyst by tableting or granulation. In the preparation method, the pseudo-boehmite material is added after the Cu-Zn coprecipitation is formed, which easily leads to uneven dispersion of active metals, thereby affecting the activity of the catalyst.

[0005] CN113731442A discloses a catalyst for hydrogenation of dimethyl maleate, its preparation method and application. The molar percentage of each element in the catalyst is Cu 30%-40%, Mn 20%-30%, Al 10%-20%, Zn 10%-20%, Ag 0%-5%, and Ru 0%-5%. By adding elements such as Al, Ag, and Ru to the catalyst, the dispersion and modification of the active components in the catalyst are achieved. Since the precipitation pH values ​​of active metals are different, when precipitating multiple metal ions, the uncontrollable precipitation order may cause the active metal precipitated first to be buried, which is not conducive to the high dispersion of active sites, thereby affecting the catalyst conversion rate and selectivity.

[0006] In summary, the catalyst for hydrogenating dimethyl maleate to 1,4-butanediol and co-producing γ-butyrolactone and tetrahydrofuran is usually prepared by co-precipitation. The key to the co-precipitation method is how to precipitate multiple ions of the constituent materials at the same time, so that the active metal is evenly dispersed in the precursor; the addition of the precipitant may cause the local concentration to be too high, resulting in precursor agglomeration, which is easy to cause sintering and deactivation of the active components of the catalyst under high temperature reaction. Therefore, how to ensure the uniform distribution of the active metal components in the catalyst precursor, so as to obtain a catalyst with good activity and selectivity after calcining the precursor has become a problem that needs to be solved urgently. Summary of the invention

[0007] In view of the shortcomings of the prior art, the present invention provides a dimethyl maleate hydrogenation catalyst precursor, a catalyst, a preparation method and an application thereof. The hydrogenation catalyst precursor has a special structure and morphology, which is conducive to the uniform distribution of the active metal Cu and improves the comprehensive performance of the catalyst. When the catalyst of the present invention is applied to the hydrogenation of dimethyl maleate, the catalyst has high catalyst activity and good selectivity, and is suitable for the hydrogenation of dimethyl maleate to produce BDO, THF and GBL.

[0008] The dimethyl maleate hydrogenation catalyst is usually prepared by coprecipitation. The inventor has found that the catalyst prepared by coprecipitation has different concentrations and precipitation speeds when precipitation occurs between the components. It is difficult for multiple ions of the constituent materials to precipitate at the same time, which may lead to uneven composition of the catalyst precursor and even agglomeration. In addition, due to the low sintering temperature of Cu, the hydrogenation reaction is accompanied by an exothermic process. When the reaction activity is too high, it will cause the Cu grains to grow spontaneously, the dispersion will decrease, and the active components of the catalyst will be sintered and deactivated, and the catalytic reaction activity will decrease. The catalyst prepared by coprecipitation is difficult to have both activity and selectivity. The inventor has found through further research that the microstructure, morphology and distribution of active metals of the catalyst and its precursor have a significant impact on the activity and selectivity of the catalyst. Through research, it was found that when pollen with a specific morphology is used as a biological template to provide active sites for the nucleation and growth of copper-zinc metal-organic framework composites (Zn / Cu-MOFs), a biological template-Zn / Cu-MOFs catalyst precursor with a highly ordered distribution of metal elements can be obtained. During the high-temperature calcination of the precursor, the organic components in the biological template and MOFs can be removed at the same time, thereby forming a CuO-ZnO catalyst with a uniform distribution of metal elements, thereby achieving improved performance of the catalyst in terms of activity and selectivity.

[0009] The first aspect of the present invention provides a dimethyl maleate hydrogenation catalyst precursor, comprising: a biological template and a copper-zinc bimetallic organic framework material.

[0010] In the present invention, the biological template is referred to as HH, the copper-zinc bimetallic organic framework material is referred to as Zn / Cu-BTC, and the precursor is referred to as HH-Zn / Cu-BTC.

[0011] Furthermore, in the precursor, the mass content of the copper-zinc bimetallic organic framework material is 50% to 95%, and the mass content of the biological template is 5% to 50%.

[0012] Furthermore, the precursor is a microsphere structure.

[0013] Furthermore, the biological template is selected from one or more of lotus pollen, sunflower pollen, rapeseed pollen, lotus pollen, and camellia pollen.

[0014] Furthermore, the particle size of the precursor is 20 to 50 μm.

[0015] Furthermore, in the precursor, the organic ligand used in the copper-zinc bimetallic organic framework material is trimesic acid.

[0016] Furthermore, in the precursor, in the copper-zinc bimetallic organic framework material, the molar ratio of copper to zinc is (0.05-5.0):1.

[0017] Furthermore, in the catalyst precursor, the copper-zinc bimetallic organic framework material is evenly distributed on the surface of the biological template, and the particle size is 50 to 700 nm.

[0018] Furthermore, in the catalyst precursor, the copper-zinc bimetallic organic framework material has a crystal form that conforms to MOF-199.

[0019] The second aspect of the present invention provides a method for preparing the above catalyst precursor, comprising:

[0020] (1) mixing the copper source solution and the bio-template, controlling the concentration of the bio-template in the mixed solution to be 0.01-0.50 g / mL, stirring under heating conditions, and then filtering and separating and collecting the precipitate;

[0021] (2) mixing the precipitate obtained in step (1) with the organic ligand solution, reacting, separating, washing, and drying to obtain a dry solid;

[0022] (3) Mixing the zinc source solution with the dry solid obtained in step (2), reacting, separating, washing, and drying to obtain a catalyst precursor.

[0023] Furthermore, in step (1), the biological template is selected from one or more of lotus pollen, sunflower pollen, rapeseed pollen, lotus pollen, and camellia pollen. The particle size of the biological template is 20 to 50 μm.

[0024] Furthermore, preferably, the biological template may be pretreated before step (1). The pretreatment may be an ultrasonic treatment in the presence of a solvent, followed by drying. The treatment conditions are as follows: temperature 25-70°C, time 0.5-5.0h. The solvent is one or more of deionized water, low-carbon alcohol (low-carbon alcohol is selected from alcohols with a carbon number of 6 or less, preferably ethanol), and N,N-dimethylformamide, and the number of ultrasonic treatments is 3-6 times. The drying conditions are as follows: drying temperature is 25-80°C, and drying time is 6-24h.

[0025] Furthermore, in step (1), the copper source may be a conventional soluble metal salt, such as at least one of nitrate, sulfate, acetate, etc. In the copper source solution, the concentration of the copper source is 0.05 to 5.0 mol / L. The solvent used in the copper source solution may be at least one of water, methanol, ethanol, N,N-dimethylformamide, etc.

[0026] Furthermore, in step (1), the copper source solution is mixed with the biological template and stirred under heating conditions at a temperature of 25 to 60° C. for a stirring time of 0.5 to 2.0 h.

[0027] Furthermore, in step (2), the organic ligand in the organic ligand solution is selected from trimesic acid, the solvent is selected from one or more of methanol, ethanol, water, and N,N-dimethylformamide (DMF), and the concentration of the organic ligand in the organic ligand solution is 0.01-1.0 mol / L.

[0028] Furthermore, in step (2), the molar ratio of the organic ligand to the copper source in step (1) is (0.5-6.5):1 in terms of copper.

[0029] Furthermore, in step (2), the reaction conditions are as follows: reacting at 25-80° C. for 0.5-5.0 h.

[0030] Furthermore, in step (2), the washing solvent used in the washing is one or more of deionized water, methanol, ethanol, and N,N-dimethylformamide, and the number of washing times is preferably 3 to 6 times. The drying conditions are as follows: the drying temperature is 25 to 80° C., and the drying time is 6 to 24 hours.

[0031] Furthermore, in step (3), the zinc source may be a conventional soluble metal salt, such as at least one of nitrate, sulfate, acetate, etc. In the zinc source solution, the concentration of the zinc source is 0.05 to 5.0 mol / L. The solvent used in the zinc source solution may be at least one of water, methanol, ethanol, N,N-dimethylformamide, etc.

[0032] Furthermore, in step (3), the reaction conditions are as follows: reacting at 25-60° C. for 0.5-5.0 h.

[0033] Furthermore, in step (3), the washing solvent used in the washing is one or more of deionized water, methanol, ethanol, and N,N-dimethylformamide, and the number of washing times is preferably 3 to 6 times. The drying conditions are as follows: the drying temperature is 25 to 80° C., and the drying time is 6 to 24 hours.

[0034] The third aspect of the present invention provides a dimethyl maleate hydrogenation catalyst, wherein the catalyst is obtained by calcining the above catalyst precursor.

[0035] Furthermore, in the catalyst, the molar ratio of copper to zinc is (0.05-5.0):1.

[0036] Furthermore, the microstructure of the catalyst is a spherical structure.

[0037] Furthermore, the calcination conditions are as follows: the calcination temperature is 300-500° C., the calcination time is 2-6 hours, the heating rate to the calcination temperature is 4-8° C. / min, and the calcination atmosphere is an oxygen-containing atmosphere, such as air.

[0038] Furthermore, the catalyst may be a shaped body, preferably a tablet-shaped body, that is, the calcined material and graphite are pressed into tablets, and the catalyst particles are obtained by screening.

[0039] The fourth aspect of the present invention provides a method for preparing the above catalyst, comprising: calcining the above catalyst precursor and pressing it into tablets to obtain the catalyst.

[0040] Furthermore, the calcination conditions are as follows: the calcination temperature is 300-500° C., the calcination time is 2-6 hours, the heating rate to the calcination temperature is 4-8° C. / min, and the calcination atmosphere is an oxygen-containing atmosphere, such as air.

[0041] Furthermore, during the catalyst tableting process, graphite powder accounting for 1% to 5% of the mass of the precursor calcined material is added, and catalyst solid particles of 20 to 40 mesh are screened out.

[0042] The fifth aspect of the present invention provides the use of the above catalyst in the hydrogenation of dimethyl maleate to synthesize 1,4-butanediol (BDO) and co-produce γ-butyrolactone (GBL) and tetrahydrofuran (THF).

[0043] Furthermore, the application includes: in the presence of hydrogen, dimethyl maleate is contacted with the catalyst to react and produce BDO, GBL and THF.

[0044] Furthermore, the catalyst of the present invention needs to be reduced and activated before use, and the reducing gas is hydrogen, or a mixture of hydrogen and nitrogen, wherein the volume ratio of H2 / N2 is (1-10): (90-99), the reducing temperature is 220-300°C, and the reducing time is 6-24h.

[0045] Furthermore, the reaction conditions are as follows: reaction temperature is 150-300°C, reaction pressure is 1-10 MPa, volume space velocity is 0.1-2.0 h -1 , the molar ratio of hydrogen to dimethyl maleate is 100-300:1.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] 1. The catalyst precursor of the present invention forms a strong interaction between CuO-ZnO in the final catalyst through the triple anchoring effect of the biological template, the metal organic framework structure and the second component ZnO on Cu. The ordered porous structure formed in the catalyst provides a good confinement effect, which is beneficial to the hydrogenation reaction, thereby improving the activity and selectivity of the catalyst in the hydrogenation of dimethyl maleate to produce BDO, GBL and THF.

[0048] 2. The bio-template used in the catalyst prepared by the method of the present invention does not require subsequent treatment steps such as acid and alkali, and the preparation process is simple and suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 This is a scanning electron microscope (SEM) image of the biological template used in Example 1;

[0050] Figure 2 This is the SEM image of the catalyst precursor obtained in Example 1;

[0051] Figure 3 The X-ray diffraction (XRD) diagrams of the catalyst precursor obtained in Example 1 and the unformed catalyst A1 after calcination;

[0052] Figure 4 This is the SEM image of the unformed catalyst A1 obtained in Example 1;

[0053] Figure 5 This is the SEM image of the catalyst precursor obtained in Example 3;

[0054] Figure 6 This is the SEM image of the catalyst precursor obtained in Comparative Example 1;

[0055] Figure 7 This is the SEM image of the catalyst precursor obtained in Comparative Example 2. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with embodiments, but it should be understood that the protection scope of the present invention is not limited by the embodiments.

[0057] Example 1

[0058] Step (1), weigh 2.495 g of anhydrous copper acetate and dissolve it in 200 mL of ethanol to prepare solution A, to which 4 g of lotus powder (particle size 20-50 μm, scanning electron microscopy image see Figure 1 ), stirred at 50°C for 1 h, and filtered to separate and collect the precipitate;

[0059] Step (2), weigh 4.202 g of trimesic acid and dissolve it in 200 mL of ethanol to prepare solution B. Add the precipitate obtained in step (1) thereto and react at 50° C. for 1 h, filter and separate, wash with ethanol 3 times, dry in an oven at 60° C. for 12 h, and collect the resulting solid;

[0060] Step (3), weigh 0.947g Zn(NO3)2·6H2O and add it to 2mL ethanol solution. After it is completely dissolved, add it to the solid obtained in step (2) and mix it. React at 50°C for 2h, filter and separate, wash with ethanol 3 times, and dry at 60°C for 12h to obtain a catalyst precursor HH-Zn / Cu-BTC. The scanning electron microscope image is shown in Figure 2 ;like Figure 2 As shown, the precursor is a microsphere structure, and particles with a diameter of 100 to 400 nm are evenly distributed on the surface of the biological template.

[0061] The catalyst precursor obtained in step (4) and step (3) was heated to 400°C at a heating rate of 5°C / min and calcined at 400°C for 2h to obtain an unformed catalyst A1 (wherein the molar ratio of Cu to Zn was 1:1.3), 3% graphite was added to form a sheet, and catalyst particles of 20 to 40 mesh were screened out to obtain the formed catalyst A1; wherein the XRD patterns of the catalyst precursor before and after calcination are shown in Figure 3 The crystal form of the catalyst precursor is consistent with MOF-199. The scanning electron micrograph of the unformed catalyst A1 is shown in Figure 4 .

[0062] Molded catalyst A1 was used for hydrogenation of dimethyl maleate. It was reduced with hydrogen before the reaction. The reduction conditions were as follows: hydrogen pressure of 0.1 MPa, reduction temperature of 270°C, reduction time of 12 h. The reaction conditions are shown in Table 1, and the reaction results are shown in Table 2.

[0063] Example 2

[0064] Step (1), weighing 2.495 g of anhydrous copper acetate and dissolving it in 200 mL of ethanol to prepare solution A, adding 8 g of lotus powder (particle size of 20-50 μm) thereto, stirring at 50° C. for 1 h, and filtering and separating the precipitate;

[0065] Step (2), weigh 4.202 g of trimesic acid and dissolve it in 200 mL of ethanol to prepare solution B; quickly add solution B to solution A under stirring, the reaction temperature is 50°C, and the reaction time is 1 hour. Filter and separate, wash with ethanol 3 times, dry in an oven at 60°C for 12 hours, and collect the resulting solid;

[0066] Step (3), weigh 0.947g Zn(NO3)2·6H2O and add it to 2mL ethanol solution. After it is completely dissolved, add it to the solid obtained in step (2) and mix, react at 50°C for 2h, filter and separate, wash with ethanol 3 times, and dry at 60°C for 12h to obtain a catalyst precursor. From the scanning electron microscope image, it can be seen that the precursor is a microsphere structure, and particles with a particle size of 100 to 400nm are evenly distributed on the surface of the biological template. From the XRD characterization, it can be seen that the crystal form of the catalyst precursor is consistent with MOF-199.

[0067] Step (4), heating the catalyst precursor obtained in step (3) to 400°C at a heating rate of 6°C / min and calcining at 400°C for 4h to obtain an unformed catalyst A2 (wherein the molar ratio of Cu to Zn is 1:0.9), adding 3% graphite to form the catalyst, and screening out catalyst particles of 20 to 40 mesh, namely, formed catalyst A2.

[0068] Molded catalyst A2 was used for the hydrogenation reaction of dimethyl maleate. The reduction conditions were the same as those in Example 1. The reaction conditions are shown in Table 1. The reaction results are shown in Table 2.

[0069] Example 3

[0070] Step (1), weigh 2.495 g of anhydrous copper acetate and dissolve it in 200 mL of ethanol to prepare solution A, add 4 g of rapeseed pollen (particle size of 20-50 μm) thereto, stir at 45° C. for 1.5 h, and filter and separate the precipitate.

[0071] Step (2), weigh 4.202 g of trimesic acid and dissolve it in 200 mL of ethanol to prepare solution B. Add the precipitate obtained in step (1) thereto and react at 60° C. for 1 h, filter and separate, wash with ethanol 3 times, dry in an oven at 60° C. for 12 h, and collect the resulting solid;

[0072] Step (3), weighing 1.894 g Zn(NO3)2·6H2O and adding it to 2 mL ethanol solution, after it is completely dissolved, adding it to the solid obtained in step (2) and mixing, reacting at 55°C for 2 h, filtering and separating, washing with ethanol three times, and drying at 60°C for 12 h to obtain a catalyst precursor; Figure 5 As shown, the precursor is a microsphere structure, and particles with a diameter of 50 to 600 nm are evenly distributed on the surface of the bio-template. XRD characterization shows that the crystal form of the catalyst precursor is consistent with MOF-199.

[0073] The catalyst precursor obtained in step (4) and step (3) was heated to 400°C at a heating rate of 7°C / min and calcined at 400°C for 2h to obtain an unformed catalyst A3 (wherein the molar ratio of Cu to Zn is 1:2.2). 3% graphite was added to form the catalyst precursor and catalyst particles of 20 to 40 mesh were screened out, namely, the formed catalyst A3.

[0074] Molded catalyst A3 was used for the hydrogenation reaction of dimethyl maleate. The reduction conditions were the same as those in Example 1. The reaction conditions are shown in Table 1. The reaction results are shown in Table 2.

[0075] Comparative Example 1

[0076] Step (1), weigh 2.495 g of anhydrous copper acetate and dissolve it in 200 mL of ethanol to prepare solution A, add 4 g of lotus powder (same as Example 1) thereto, stir at 50° C. for 1 h, and filter and separate the precipitate.

[0077] Step (2), weigh 4.202 g of trimesic acid and dissolve it in 200 mL of ethanol to prepare solution B. Add the precipitate obtained in step (1) to the solution and react at 50° C. for 1 h, filter and separate, wash with ethanol 3 times, and dry in an oven at 60° C. for 12 h to obtain a catalyst precursor; Figure 6 As shown, the precursor is a microsphere structure, and particles with a diameter of 50 to 400 nm are distributed on the surface of the biological template.

[0078] The catalyst precursor obtained in step (3) and step (2) was heated to 400°C at a heating rate of 5°C / min and calcined at 400°C for 2h to obtain an unformed catalyst B1. 3% graphite was added to form the catalyst and the catalyst particles of 20 to 40 mesh were screened out, namely the formed catalyst B1.

[0079] Molded catalyst B1 was used for the hydrogenation reaction of dimethyl maleate. The reaction conditions are shown in Table 1, and the reaction results are shown in Table 2.

[0080] Comparative Example 2

[0081] Step (1), weighing 2.495 g of anhydrous copper acetate and dissolving it in 200 mL of ethanol to prepare solution A, adding 4 g of lotus powder (same as in Example 1) thereto, stirring at 50° C. for 1 h, and filtering and separating the precipitate;

[0082] Step (2), weigh 4.202 g of trimesic acid and dissolve it in 200 mL of ethanol to prepare solution B. Add the precipitate obtained in step (1) thereto and react at 50° C. for 1 h.

[0083] Step (3), weighing 0.947 g Zn(NO3)2·6H2O and adding it to the mother liquor obtained in step (2), reacting at 50°C for 2 h, filtering and separating, washing with ethanol three times, and drying at 60°C for 12 h to obtain a catalyst precursor; Figure 7 As shown, the precursor is a microsphere structure with a particle size of 0.05 to 5 μm and is dispersed on the surface of the biological template.

[0084] Step (4), the catalyst precursor obtained in step (3) is heated to 400°C at a heating rate of 5°C / min and calcined at 400°C for 2h to obtain an unformed catalyst B2, 3% graphite is added to form the catalyst, and catalyst particles of 20 to 40 mesh are screened out, namely, the formed catalyst B2; the formed catalyst B2 is used for the hydrogenation reaction of dimethyl maleate, the reduction conditions are the same as those in Example 1, the reaction conditions are shown in Table 1, and the reaction results are shown in Table 2.

[0085] Comparative Example 3

[0086] Step (1), weigh 1.208 g Cu(NO3)2·3H2O and 0.947 g Zn(NO3)2·6H2O and dissolve them in 100 mL deionized water to prepare solution A;

[0087] Step (2), weigh 1.060 g of sodium carbonate and dissolve it in 100 mL of deionized water to prepare solution B;

[0088] Step (3), add 8 mL of bottom water to the reaction tank, raise the temperature to 65°C, add solution A and solution B to the reaction tank in parallel under stirring, control the solution pH value to 7.0±0.1, and the reaction time is 1 hour. Start aging under stirring, the aging temperature is 70°C, and the aging time is 2 hours;

[0089] Step (4), after aging, the obtained material is filtered, the filtered product is washed three times with deionized water and then dried in an oven at 60° C. for 12 h to obtain a catalyst precursor;

[0090] The catalyst precursor obtained in step (5) and step (4) was heated to 400°C at a heating rate of 5°C / min and calcined at 400°C for 4h to obtain an unformed catalyst B3 (wherein the molar ratio of Cu to Zn was 1:0.9). 3% graphite was added to form the catalyst and the catalyst particles of 20 to 40 mesh were screened out, namely the formed catalyst B3.

[0091] The molded catalyst B3 was used for the hydrogenation reaction of dimethyl maleate. The reduction conditions were the same as those in Example 1. The reaction conditions are shown in Table 1. The reaction results are shown in Table 2.

[0092] Comparative Example 4

[0093] Step (1), weighing 2.495 g of anhydrous copper acetate and dissolving it in 200 mL of ethanol to prepare solution A, adding 4 g of lotus powder (same as in Example 1) thereto, stirring at 50° C. for 1 h, and filtering and separating the precipitate;

[0094] Step (2), weigh 4.202 g of trimesic acid and dissolve it in 200 mL of ethanol to prepare solution B. Add the precipitate obtained in step (1) thereto and react at 50° C. for 1 h, filter and separate, wash with ethanol 3 times, dry in an oven at 60° C. for 12 h, and collect the resulting solid;

[0095] Step (3), weigh 0.947 g Zn(NO3)2·6H2O and add it to 2 mL ethanol solution. After it is completely dissolved, add it to the solid obtained in step (2) and mix. React at 50°C for 2 h, filter and separate, wash with ethanol three times, and dry at 60°C for 12 h to obtain a catalyst precursor.

[0096] The catalyst precursor obtained in step (4) and step (3) was heated to 400°C at a heating rate of 2°C / min and calcined at 400°C for 2h to obtain an unformed catalyst B4 (wherein the molar ratio of Cu to Zn was 1:1.3), 3% graphite was added to form the catalyst, and catalyst particles of 20 to 40 mesh were screened out, namely, formed catalyst B4;

[0097] The molded catalyst B4 was used for the hydrogenation reaction of dimethyl maleate. It was reduced with hydrogen before the reaction. The reduction conditions were as follows: hydrogen pressure was 0.1 MPa, reduction temperature was 270°C, and reduction time was 12 h. The reaction conditions are shown in Table 1, and the reaction results are shown in Table 2.

[0098] Table 1 Process conditions

[0099]

[0100]

[0101] Table 2 Evaluation results of the catalysts obtained in each case

[0102]

[0103] The embodiments of the present invention are only detailed descriptions of the technical solutions of the present invention, but the present invention is not limited to the above embodiments, that is, the present invention can be implemented without relying on the steps described in the above embodiments. In summary, any improvements made to the present invention by those skilled in the art, as long as they do not deviate from the content of the technical solutions of the present invention, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention, shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A dimethyl maleate hydrogenation catalyst precursor, comprising: Biotemplates and copper-zinc bimetallic organic frameworks.

2. The precursor according to claim 1, characterized in that: In the precursor, the mass content of the copper-zinc bimetallic organic framework material is 50% to 95%, and the mass content of the biological template is 5% to 50%.

3. The precursor according to claim 1, characterized in that: The precursor is a microsphere structure; and / or the particle size of the precursor is 20 to 50 μm.

4. The precursor according to claim 1, characterized in that: The biological template is selected from one or more of lotus pollen, sunflower pollen, rapeseed pollen, lotus pollen and camellia pollen.

5. The precursor according to claim 1, characterized in that: In the precursor, the organic ligand used in the copper-zinc bimetallic organic framework material is trimesic acid; and / or, in the copper-zinc bimetallic organic framework material, the molar ratio of copper to zinc is (0.05-5.0):

1.

6. The precursor according to claim 1, characterized in that: In the catalyst precursor, the copper-zinc bimetallic organic framework material is evenly distributed on the surface of the biological template, and the particle size is 50-700nm.

7. The precursor according to claim 1, characterized in that: In the catalyst precursor, the copper-zinc bimetallic organic framework material has a crystal form that conforms to MOF-199.

8. The method for preparing the catalyst precursor according to any one of claims 1 to 7, comprising: (1) mixing the copper source solution and the bio-template, controlling the concentration of the bio-template in the mixed solution to be 0.01-0.50 g / mL, stirring under heating conditions, and then filtering and separating and collecting the precipitate; (2) mixing the precipitate obtained in step (1) with the organic ligand solution, reacting, separating, washing, and drying to obtain a dry solid; (3) Mixing the zinc source solution with the dry solid obtained in step (2), reacting, separating, washing, and drying to obtain a catalyst precursor.

9. The method according to claim 8, characterized in that In step (1), the copper source is a soluble metal salt, preferably at least one of nitrate, sulfate, and acetate; the concentration of the copper source in the copper source solution is 0.05 to 5.0 mol / L; the solvent used in the copper source solution is at least one of water, methanol, ethanol, and N,N-dimethylformamide; And / or, in step (2), the organic ligand in the organic ligand solution is selected from trimesic acid, the solvent is selected from one or more of methanol, ethanol, water, and N,N-dimethylformamide, and the concentration of the organic ligand in the organic ligand solution is 0.01 to 1.0 mol / L; And / or, in step (2), the molar ratio of the organic ligand to the copper source in step (1) is (0.5-6.5) : 1 in terms of copper; And / or, in step (3), the zinc source is a soluble metal salt, preferably at least one of nitrate, sulfate, and acetate, the concentration of the zinc source in the zinc source solution is 0.05 to 5.0 mol / L, and the solvent used in the zinc source solution is at least one of water, methanol, ethanol, and N,N-dimethylformamide.

10. The method according to claim 8, characterized in that In step (1), the biological template is selected from one or more of lotus pollen, sunflower pollen, rapeseed pollen, lotus pollen, and camellia pollen; and / or the particle size of the biological template is 20 to 50 μm.

11. The method according to claim 8, characterized in that In step (1), the copper source solution is mixed with the biological template and stirred under heating conditions at a temperature of 25 to 60° C. for a stirring time of 0.5 to 2.0 h; And / or, in step (2), the reaction conditions are as follows: reacting at 25-80° C. for 0.5-5.0 h; And / or, in step (2), the drying conditions are as follows: drying temperature is 25 to 80° C., and drying time is 6 to 24 h; And / or, in step (3), the reaction conditions are as follows: reacting at 25-60° C. for 0.5-5.0 h; And / or, in step (3), the drying conditions are as follows: the drying temperature is 25 to 80° C., and the drying time is 6 to 24 hours.

12. A dimethyl maleate hydrogenation catalyst, characterized in that: The product is obtained by calcining the precursor according to any one of claims 1 to 7 or the precursor obtained by any one of claims 8 to 11.

13. The catalyst according to claim 12, characterized in that In the catalyst, the molar ratio of copper to zinc is (0.05-5.0):

1.

14. The catalyst according to claim 12, characterized in that The microstructure of the catalyst is a spherical structure.

15. The catalyst according to claim 12, characterized in that The calcination conditions are as follows: the heating rate to the calcination temperature is 4-8°C / min, the calcination temperature is 300-500°C, the calcination time is 2-6h, and the calcination atmosphere is an oxygen-containing atmosphere.

16. A method for preparing a dimethyl maleate hydrogenation catalyst, comprising: The catalyst is obtained by calcining the precursor according to any one of claims 1 to 7 or the precursor obtained by any one of claims 8 to 11.

17. The preparation method according to claim 16, characterized in that: The calcination conditions are as follows: the heating rate to the calcination temperature is 4-8°C / min, the calcination temperature is 300-500°C, the calcination time is 2-6h, and the calcination atmosphere is an oxygen-containing atmosphere.

18. Use of the catalyst according to any one of claims 12 to 15 or the catalyst prepared by any one of the methods of claims 16 to 17 in the hydrogenation of dimethyl maleate to synthesize 1,4-butanediol and co-produce γ-butyrolactone and tetrahydrofuran.

19. The use according to claim 18, characterized in that The reaction conditions are as follows: reaction temperature is 150-300°C, reaction pressure is 1-10 MPa, volume space velocity is 0.1-2.0 h -1 , the molar ratio of hydrogen to dimethyl maleate is 100-300:1.

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