Catalyst for preparing succinic anhydride and preparation method thereof

Abstract

The invention relates to a catalyst for succinic anhydride preparation and a preparation method thereof, and belongs to the field of catalyst.The preparation method comprises the following steps that S1, nickel salt and auxiliary metal salt are dissolved in water and stirred to be uniform, an active solution is obtained for standby application, the mass concentration of the nickel salt in the water is 0.18-0.22 mol / L, and the mass concentration of the auxiliary metal salt in the water is 0.05-0.1 mol / L; s2, the multi-layer core-shell microsphere carrier is placed in a functional solution to be subjected to micro-etching treatment, vacuumizing is conducted at 0.04-0.08 Mpa, stirring is conducted for 4-6 min, filtering and drying are conducted, and a pretreated carrier is obtained; s3, putting the pretreated carrier in the S2 into the active solution prepared in the S1, carrying out dipping treatment for 10-20 hours, filtering, drying at 80-120 DEG C for 6-10 hours, and roasting at 450-550 DEG C for 4-5 hours to obtain an active carrier; and S4, placing the active carrier in the S3 in a hydrogen atmosphere with an air speed of 2000-3000 h <-1 >, and carrying out heating reduction at 200-400 DEG C for 2-6 h to obtain the catalyst for succinic anhydride preparation. The catalyst for preparing butanedioic anhydride prepared by the invention has high selectivity and stability, and butanedioic anhydride products prepared by the catalyst are high in purity.

Description

Technical Field

[0001] The present invention belongs to the field of catalysis, and particularly relates to a catalyst for the preparation of succinic anhydride and a preparation method thereof. Background Art

[0002] The production methods of succinic anhydride mainly include biological fermentation method, succinic acid dehydration method and maleic anhydride hydrogenation method. Among them, the maleic anhydride hydrogenation method has the highest conversion rate of succinic anhydride. At the same time, this method also has great advantages in process flow, operating conditions and production cost, and is widely used in industrial production.

[0003] The catalyst used in the maleic anhydride hydrogenation method is mainly prepared by loading the active component of metallic nickel on a porous support. The porous structure of the support has a large specific surface area, which makes the catalyst have high conversion rate and selectivity. However, during long-term operation, phenomena such as aggregation of active metals, pore blockage and loss of active components are likely to occur. In addition, the maleic anhydride solution has certain acidity, and the porous support structure of the catalyst is easily damaged under acidic conditions, resulting in collapse and deformation of pores, so that the distribution of active sites of the catalyst is quite different. Eventually, the adsorption and reaction rates of reactants on different active sites are different, and the activity in some regions is too high or too low, resulting in a significant decrease in product selectivity and a large increase in by-products, affecting the use effect of the catalyst.

[0004] Therefore, it is very necessary to study a maleic anhydride hydrogenation catalyst to fundamentally solve the problems of poor selectivity and low product purity during the long-term operation of the catalyst, so as to improve the industrial production efficiency of succinic anhydride. Summary of the Invention

[0005] (I) Technical Problems to be Solved Aiming at the deficiencies of the prior art, the present invention provides a catalyst for the preparation of succinic anhydride and a preparation method thereof.

[0006] (II) Technical Solutions To achieve the above purposes, the present invention is realized through the following technical solutions: A catalyst for the preparation of succinic anhydride, and its preparation method includes the following steps: S1: Dissolve nickel salt and promoter metal salt in water, stir evenly to obtain an active solution for standby. The mass concentration of nickel salt in water is 0.18 - 0.22 mol / L, and the mass concentration of promoter metal salt in water is 0.05 - 0.1 mol / L; S2: Place the multi-layer core-shell microsphere support in a functional solution for micro-etching treatment, evacuate to 0.04 - 0.08 Mpa, stir for 4 - 6 min, filter, and dry to obtain a pretreated support; S3: Place the pretreated carrier in S2 into the active solution prepared in S1, perform impregnation treatment for 10 - 20 h, filter, dry at 80 - 120 °C for 6 - 10 h, and calcine at 450 - 550 °C for 4 - 5 h to obtain an active carrier; S4: Place the active carrier in S3 under a hydrogen atmosphere with a space velocity of 2000 - 3000 h -1 and heat and reduce it at 200 - 400 °C for 2 - 6 h to obtain the catalyst for preparing succinic anhydride.

[0007] Furthermore, the preparation method of the functional solution is as follows: Dissolve the chelating agent in an aqueous sodium hydroxide solution, prepare 100 L of the mixed solution, cool it down to 3 - 8 °C, add 20 - 30 g of carbon nanotubes and 30 - 50 parts of sodium dodecyl sulfate to the mixed solution, and stir for 10 - 20 min to obtain the functional solution.

[0008] Furthermore, in the preparation of the functional solution, the molar concentration of sodium hydroxide in the mixed solution is 0.4 - 0.6 mol / L, and the molar concentration of the chelating agent in the mixed solution is 0.08 - 0.12 mol / L.

[0009] The chelating agent is any one of sodium hexametaphosphate and sodium tripolyphosphate or a mixture of the two in any proportion.

[0010] Furthermore, the preparation method of the multi - layer core - shell microsphere carrier includes the following steps: Q1: By weight, add 1 part of aluminum isopropoxide to 10 - 15 parts of deionized water, stir evenly, dropwise add a nitric acid solution with a mass fraction of 5 - 10%, adjust the pH to 1 - 2, stir for 20 - 40 min, add 0.2 - 0.3 part of carboxymethyl cellulose and 0.5 - 0.8 part of hexamethylenetetramine (HMT), and stir for 0.5 - 1 h to obtain an aluminum sol solution; Q2: Prepare a n - octanol solution with a mass concentration of 1.5 - 2% sorbitan trioleate and 10 - 15% tri - n - octylamine, heat it in a water bath to 70 - 80 °C, add the aluminum sol solution of Q1, stir rapidly for 1 - 2 h to obtain a gelled liquid, and let it stand for 2 - 4 h to obtain gelled and solidified microspheres; Q3: Vacuum - dry the gelled and solidified microspheres at 80 - 90 °C for 6 - 10 h, and then calcine them at 500 - 600 °C for 3 - 4 h to obtain the multi - layer core - shell microsphere carrier.

[0011] Furthermore, the nickel salt in S1 is one or more of nickel nitrate, nickel chloride, nickel acetate, and nickel sulfate.

[0012] Furthermore, the promoter metal salt in S1 is any one of cerium nitrate and lanthanum nitrate or a mixture of the two in a mass ratio of 1:1.

[0013] A catalyst for the preparation of succinic anhydride is prepared by the above-mentioned preparation method.

[0014] After adopting the above technical solution, compared with the prior art, the present invention has the following beneficial effects: 1. The multi-layer core-shell microsphere carrier obtained by the gelation treatment in the present invention can provide a strong framework for the catalyst. Through the vacuum micro-etching of the alkali solution, the roughening treatment of the carrier surface is completed, providing conditions for the anchoring and positioning and uniform dispersion of the chelate and the active component. By impregnating the active metal salt solution and loading the active component, the tight combination of the carrier, chelate and active metal ions and the uniform distribution of the active sites are realized, avoiding and reducing the shedding or transfer of the active sites, effectively improving the selectivity of maleic anhydride during the long-term use of the catalyst, and extending the service life of the catalyst.

[0015] 2. The micro-etching penetration of the alkaline solution on the multi-layer core-shell microsphere carrier can promote the combination of the chelate and the carrier to a certain extent, improve the hydrogenation function of the catalyst. At the same time, the carbon nanotubes can make the chelate settle uniformly on the surface of the carrier core-shell structure, effectively avoiding the precipitation of active substances, ensuring the stability of the chelate, and finally realizing the synergistic effect of the multi-layer core-shell microsphere carrier and the chelate on the active substance, effectively improving the problem of poor selectivity during the continuous operation of the catalyst.

[0016] 3. The present invention provides a maleic anhydride hydrogenation catalyst and its preparation method, which fundamentally solves the problems of poor selectivity and low product purity during the long-term operation of the catalyst, and effectively improves the industrial production efficiency of succinic anhydride. Detailed implementation manners

[0017] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The description of at least one exemplary embodiment below is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0018] Example 1 The technical solution of the present invention is a preparation method of a catalyst for the preparation of succinic anhydride, which specifically includes the following steps: I. Preparation of a functional solution, the method is as follows: Dissolve a chelating agent in an aqueous sodium hydroxide solution to prepare 100 L of a mixed solution, cool it down to 5 °C, add 25 g of carbon nanotubes and 40 parts of sodium dodecyl sulfate to the mixed solution, and stir for 15 min to obtain a functional solution, wherein the molar concentration of sodium hydroxide in the mixed solution is 0.5 mol / L, and the molar concentration of the chelating agent in the mixed solution is 0.1 mol / L; the chelating agent is sodium hexametaphosphate.

[0019] II. Preparation of a multi-layer core-shell microsphere carrier, specifically including the following steps: Q1: Add 1 part of aluminum isopropoxide to 12 parts of deionized water by weight, stir evenly, dropwise add a nitric acid solution with a mass fraction of 8%, adjust the pH to 1, stir for 30 min, add 0.25 part of carboxymethyl cellulose and 0.6 part of hexamethylenetetramine (HMT), and stir for 0.5 h to obtain an aluminum sol solution; Q2: Prepare a n-octanol solution with a mass concentration of 1.5% sorbitan trioleate and 10% tri-n-octylamine, heat it in a water bath to 75 °C, add the aluminum sol solution of Q1, stir rapidly for 1.5 h to obtain a gelled liquid, and let it stand for 3 h to obtain gelled and solidified microspheres; Q3: Vacuum dry the gelled and solidified microspheres at 85 °C for 8 h, and then calcine them at 550 °C for 3 h to obtain a multi-layer core-shell microsphere carrier.

[0020] III. Finally, prepare a catalyst for the preparation of succinic anhydride, and its preparation method includes the following steps: S1: Dissolve a nickel salt and a promoter metal salt in water, stir evenly to obtain an active solution for standby, wherein the mass concentration of the nickel salt in water is 0.2 mol / L, and the mass concentration of the promoter metal salt in water is 0.08 mol / L; S2: Place the multi-layer core-shell microsphere carrier in the functional solution for micro-etching treatment, evacuate to 0.06 Mpa, stir for 5 min, filter, and dry to obtain a pretreated carrier; S3: Place the pretreated carrier in S2 into the active solution prepared in S1, carry out impregnation treatment for 15 h, filter, dry at 100 °C for 8 h, and calcine at 500 °C for 4 h to obtain an active carrier; S4: Place the active carrier in S3 in a hydrogen atmosphere with a space velocity of 2500 h -1 and heat and reduce it at 300 °C for 4 h to obtain the catalyst for the preparation of succinic anhydride.

[0021] The nickel salt in S1 is nickel nitrate.

[0022] The promoter metal salt in S1 is cerium nitrate.

[0023] Example 2 The technical solution of the present invention is a preparation method of a catalyst for the preparation of succinic anhydride, which specifically includes the following steps: I. Prepare a functional solution as follows: Dissolve the chelating agent in an aqueous sodium hydroxide solution to prepare 100 L of a mixed solution. Cool the temperature to 3 °C, add 20 g of carbon nanotubes and 30 parts of sodium dodecyl sulfate to the mixed solution, and stir for 10 min to obtain the functional solution, wherein the molar concentration of sodium hydroxide in the mixed solution is 0.4 mol / L, and the molar concentration of the chelating agent in the mixed solution is 0.08 mol / L; the chelating agent is sodium tripolyphosphate.

[0024] II. Prepare a multi-layer core-shell microsphere carrier, which specifically includes the following steps: Q1: Add 1 part of aluminum isopropoxide to 10 parts of deionized water by weight, stir evenly, dropwise add a 5% nitric acid solution, adjust the pH to 12, stir for 20 min, add 0.2 part of carboxymethyl cellulose and 0.5 part of hexamethylenetetramine (HMT), and stir for 0.5 h to obtain an aluminum sol solution; Q2: Prepare a n-octanol solution of 1.5% sorbitan trioleate and 10% tri-n-octylamine, heat it in a water bath to 70 °C, add the aluminum sol solution of Q1, and stir rapidly for 1 h to obtain a gelled liquid. Let it stand for 2 h to obtain gelled and solidified microspheres; Q3: Vacuum-dry the gelled and solidified microspheres at 80 °C for 6 h, and then calcine them at 500 °C for 3 h to obtain a multi-layer core-shell microsphere carrier.

[0025] III. Finally, prepare a catalyst for the preparation of succinic anhydride, and its preparation method includes the following steps: S1: Dissolve nickel salt and promoter metal salt in water, stir evenly to obtain an active solution for standby, wherein the mass concentration of nickel salt in water is 0.18 mol / L, and the mass concentration of promoter metal salt in water is 0.05 mol / L; S2: Place the multi-layer core-shell microsphere carrier in the functional solution for micro-etching treatment, evacuate to 0.04 Mpa, stir for 4 min, filter, and dry to obtain a pretreated carrier; S3: Place the pretreated carrier in S2 into the active solution prepared in S1, carry out impregnation treatment for 10 h, filter, dry at 80 °C for 6 h, and calcine at 450 °C for 4 h to obtain an active carrier; S4: Place the active carrier in S3 in a hydrogen atmosphere with a space velocity of 2000 h -1 and heat and reduce it at 200 °C for 2 h to obtain the catalyst for the preparation of succinic anhydride.

[0026] The nickel salt in S1 is nickel chloride.

[0027] The promoter metal salt in S1 is lanthanum nitrate.

[0028] Example 3 The technical solution of the present invention is a preparation method of a catalyst for succinic anhydride preparation, which specifically includes the following steps: I. Prepare a functional solution as follows: Dissolve a chelating agent in an aqueous sodium hydroxide solution to prepare 100 L of a mixed solution. Cool the temperature to 8 °C, add 30 g of carbon nanotubes and 50 parts of sodium dodecyl sulfate to the mixed solution, and stir for 20 min to obtain a functional solution. The molar concentration of sodium hydroxide in the mixed solution is 0.6 mol / L, and the molar concentration of the chelating agent in the mixed solution is 0.12 mol / L; the chelating agent is sodium tripolyphosphate.

[0029] II. Prepare a multi-layer core-shell microsphere carrier, which specifically includes the following steps: Q1: Add 1 part of aluminum isopropoxide to 15 parts of deionized water by weight, stir evenly, dropwise add a 10% nitric acid solution, adjust the pH to 2, stir for 40 min, add 0.3 part of carboxymethyl cellulose and 0.8 part of hexamethylenetetramine (HMT), and stir for 1 h to obtain an aluminum sol solution; Q2: Prepare a n-octanol solution with a mass concentration of 2% sorbitan trioleate and 15% tri-n-octylamine, heat it in a water bath to 80 °C, add the aluminum sol solution of Q1, and stir rapidly for 2 h to obtain a gelified liquid. Let it stand for 4 h to obtain gel-cured microspheres; Q3: Vacuum-dry the gel-cured microspheres at 90 °C for 10 h, and then calcine them at 600 °C for 4 h to obtain a multi-layer core-shell microsphere carrier.

[0030] III. Finally, prepare a catalyst for succinic anhydride preparation, and its preparation method includes the following steps: S1: Dissolve nickel salt and promoter metal salt in water, stir evenly, and obtain an active solution for standby. The mass concentration of nickel salt in water is 0.22 mol / L, and the mass concentration of promoter metal salt in water is 0.1 mol / L; S2: Place the multi-layer core-shell microsphere carrier in the functional solution for micro-etching treatment, evacuate to 0.08 Mpa, stir for 6 min, filter, and dry to obtain a pretreated carrier; S3: Place the pretreated carrier in S2 into the active solution prepared in S1, perform impregnation treatment for 20 h, filter, dry at 120 °C for 10 h, and calcine at 550 °C for 5 h to obtain an active carrier; S4: Place the active carrier in S3 under a hydrogen atmosphere with a space velocity of 3000 h -1 and heat and reduce it at 400 °C for 6 h to obtain the catalyst for succinic anhydride preparation.

[0031] The nickel salt in S1 is one or more of nickel nitrate, nickel chloride, nickel acetate, and nickel sulfate.

[0032] In S1, the promoter metal salt is one or more of cerium nitrate and lanthanum nitrate.

[0033] Example 4 The technical solution of the present invention is a preparation method of a catalyst for the preparation of succinic anhydride, which specifically includes the following steps: I. Prepare a functional solution as follows: Dissolve the chelating agent in an aqueous sodium hydroxide solution to prepare 100 L of a mixed solution, cool it to 4 °C, add 22 g of carbon nanotubes and 35 parts of sodium dodecyl sulfate to the mixed solution, and stir for 13 min to obtain a functional solution, wherein the molar concentration of sodium hydroxide in the mixed solution is 0.45 mol / L, and the molar concentration of the chelating agent in the mixed solution is 0.09 mol / L; the chelating agent is a mixture of sodium hexametaphosphate and sodium tripolyphosphate mixed in a mass ratio of 1:1.

[0034] II. Prepare a multi-layer core-shell microsphere carrier, which specifically includes the following steps: Q1: Add 1 part of aluminum isopropoxide to 12 parts of deionized water by weight, stir evenly, dropwise add a 6% nitric acid solution, adjust the pH to 1.2, stir for 25 min, add 0.23 part of carboxymethyl cellulose and 0.55 part of hexamethylenetetramine (HMT), and stir for 0.6 h to obtain an aluminum sol solution; Q2: Prepare a n-octanol solution of sorbitan trioleate with a mass concentration of 1.6% and tri-n-octylamine with a mass concentration of 11%, heat it in a water bath to 73 °C, add the aluminum sol solution of Q1, stir rapidly for 1.2 h to obtain a gelled liquid, and let it stand for 2.5 h to obtain gelled and solidified microspheres; Q3: Vacuum dry the gelled and solidified microspheres at 84 °C for 7 h, and then calcine them at 520 °C for 3.4 h to obtain a multi-layer core-shell microsphere carrier.

[0035] III. Finally, prepare a catalyst for the preparation of succinic anhydride, and its preparation method includes the following steps: S1: Dissolve the nickel salt and the promoter metal salt in water, stir evenly to obtain an active solution for standby, wherein the mass concentration of the nickel salt in water is 0.19 mol / L, and the mass concentration of the promoter metal salt in water is 0.06 mol / L; S2: Place the multi-layer core-shell microsphere carrier in the functional solution for micro-etching treatment, evacuate to 0.05 Mpa, stir for 4.5 min, filter, and dry to obtain a pretreated carrier; S3: Place the pretreated carrier in S2 into the active solution prepared in S1, perform impregnation treatment for 14 h, filter, dry at 90 °C for 7 h, and calcine at 460 °C for 4.3 h to obtain an active carrier; S4: Place the active carrier in S3 at a space velocity of 2200 h -1Under a hydrogen atmosphere, heat and reduce at 250 °C for 3 h to obtain the catalyst for preparing succinic anhydride.

[0036] In the step S1, the nickel salt is nickel acetate.

[0037] In the step S1, the promoter metal salt is a mixture formed by mixing cerium nitrate and lanthanum nitrate according to a mass ratio of 1:1.

[0038] Example 5 The technical solution of the present invention is a preparation method of a catalyst for preparing succinic anhydride, which specifically includes the following steps: I. Prepare a functional solution, and the method is as follows: Dissolve a chelating agent in an aqueous sodium hydroxide solution to prepare 100 L of a mixed solution, cool it down to 7 °C, add 28 g of carbon nanotubes and 45 parts of sodium dodecyl sulfate to the mixed solution, and stir for 17 min to obtain a functional solution, wherein the molar concentration of sodium hydroxide in the mixed solution is 0.55 mol / L, and the molar concentration of the chelating agent in the mixed solution is 0.11 mol / L; the chelating agent is any one of sodium hexametaphosphate and sodium tripolyphosphate or a mixture formed by mixing the two in any proportion.

[0039] II. Prepare a multi-layer core-shell microsphere carrier, which specifically includes the following steps: Q1: By weight, add 1 part of aluminum isopropoxide to 14 parts of deionized water, stir evenly, dropwise add a nitric acid solution with a mass fraction of 9%, adjust the pH to 1.9, stir for 35 min, add 0.28 part of carboxymethyl cellulose and 0.75 part of hexamethylenetetramine (HMT), and stir for 0.5 - 1 h to obtain an aluminum sol solution; Q2: Prepare a n-octanol solution with a mass concentration of 1.8% sorbitan trioleate and 14% tri-n-octylamine, heat it in a water bath to 78 °C, add the aluminum sol solution of Q1, stir rapidly for 1.8 h to obtain a gelled liquid, and let it stand for 3.5 h to obtain gelled and solidified microspheres; Q3: Vacuum dry the gelled and solidified microspheres at 88 °C for 9 h, and then calcine them at 590 °C for 3.7 h to obtain a multi-layer core-shell microsphere carrier.

[0040] III. Finally, prepare the catalyst for preparing succinic anhydride, and its preparation method includes the following steps: S1: Dissolve the nickel salt and the promoter metal salt in water, stir evenly to obtain an active solution for standby, wherein the mass concentration of the nickel salt in water is 0.21 mol / L, and the mass concentration of the promoter metal salt in water is 0.09 mol / L; S2: Place the multi-layer core-shell microsphere carrier in the functional solution for micro-etching treatment, evacuate to 0.07 Mpa, stir for 5.5 min, filter, and dry to obtain a pretreated carrier; S3: Place the pretreated carrier in S2 into the active solution prepared in S1, perform impregnation treatment for 18 h, filter, dry at 115 °C for 9 h, and calcine at 540 °C for 4.9 h to obtain an active carrier; S4: Place the active carrier in S3 under a hydrogen atmosphere with a space velocity of 2900 h -1 and heat and reduce it at 350 °C for 5.5 h to obtain the catalyst for preparing succinic anhydride.

[0041] The nickel salt in S1 is nickel sulfate.

[0042] The promoter metal salt in S1 is cerium nitrate.

[0043] Comparative Example 1 The difference from Example 1 is only that sodium hydroxide is not added in the preparation of the functional solution.

[0044] The method for the functional solution includes the following: Dissolve the chelating agent in water, prepare a 100 L chelating agent solution, cool it to 5 °C, add 25 g of carbon nanotubes and 40 parts of sodium dodecyl sulfate to the chelating agent solution, and stir for 15 min to obtain the functional solution, where the molar concentration of sodium hydroxide in the mixture is 0.5 mol / L and the molar concentration of the chelating agent in the chelating agent solution is 0.1 mol / L; the chelating agent is sodium hexametaphosphate.

[0045] Comparative Example 2 The difference from Example 1 is only that the chelating agent is not added in the preparation of the functional solution.

[0046] The method for the functional solution includes the following: Take 100 L of an aqueous sodium hydroxide solution with a molar concentration of 0.5 mol / L, cool it to 5 °C, add 25 g of carbon nanotubes and 40 parts of sodium dodecyl sulfate, and stir for 15 min to obtain the functional solution.

[0047] Comparative Example 3 The difference from Example 1 is only that the gelation treatment is not performed in the preparation of the multi-layer core-shell microsphere carrier.

[0048] The preparation method of the multi-layer core-shell microsphere carrier specifically includes the following steps: Q1: By weight, add 1 part of aluminum isopropoxide to 12 parts of deionized water, stir evenly, dropwise add a nitric acid solution with a mass fraction of 8%, adjust the pH to 1, stir for 30 min, add 0.25 part of carboxymethyl cellulose and 0.6 part of hexamethylenetetramine (HMT), stir for 0.5 h to obtain an aluminum sol solution, then stir rapidly for 1.5 h to obtain a gelation liquid, and let it stand for 3 h to obtain gel-cured microspheres; Q2: Vacuum-dry the gel-cured microspheres at 85 °C for 8 h, and then calcine them at 550 °C for 3 h to obtain the multi-layer core-shell microsphere carrier.

[0049] Comparative Example 4 The difference from Example 1 is only that in the preparation of the functional solution, no chelating agent is added, and in the preparation of the multi-layer core-shell microsphere carrier, no gelation treatment is carried out.

[0050] The method for the functional solution is as follows: Take 100 L of an aqueous sodium hydroxide solution with a molar concentration of 0.5 mol / L, cool it to 5 °C, add 25 g of carbon nanotubes and 40 parts of sodium dodecyl sulfate, and stir for 15 min to obtain the functional solution.

[0051] The preparation method of the multi-layer core-shell microsphere carrier specifically includes the following steps: Q1: By weight, add 1 part of aluminum isopropoxide to 12 parts of deionized water, stir evenly, dropwise add a nitric acid solution with a mass fraction of 8%, adjust the pH to 1, stir for 30 min, add 0.25 part of carboxymethyl cellulose and 0.6 part of hexamethylenetetramine (HMT), stir for 0.5 h to obtain an aluminum sol solution, then stir rapidly for 1.5 h to obtain a gelation liquid, and let it stand for 3 h to obtain gel-cured microspheres; Q2: Vacuum dry the gel-cured microspheres at 85 °C for 8 h, and then calcine them at 550 °C for 3 h to obtain the multi-layer core-shell microsphere carrier.

[0052] Effect verification: The catalysts obtained in the examples and comparative examples were subjected to a hydrogenation reaction. The specific content is as follows: Add the hydrogenation catalyst to a 1,4-dioxane solution containing 10% maleic anhydride, introduce hydrogen at the bottom, the molar ratio of hydrogen to maleic anhydride is 10:1, the reaction temperature is 90 °C, and the reaction pressure is 3 Mpa. After the catalyst was continuously used for 1000 h, the conversion rate of maleic anhydride and the selectivity of succinic anhydride were detected. The specific results are shown in Table 1: Table 1 Combined with Examples 1 to 5 and the data in Table 1, it can be seen that the catalyst for preparing succinic anhydride prepared by the technical solution of the present invention has high selectivity and stability, and has a high conversion rate for maleic anhydride.

[0053] Combined with the content of Comparative Example 1, the data in Table 1 and the content of Example 1, it can be seen that after the catalyst for preparing succinic anhydride prepared in Comparative Example 1 was used for 1000 h, the conversion rate of maleic anhydride and the selectivity of succinic anhydride after being catalyzed by the catalyst of this comparative example both decreased, proving that the addition of the alkaline solution sodium hydroxide improved the selectivity and stability of the prepared catalyst for preparing succinic anhydride, and at the same time improved the conversion rate of maleic anhydride and the selectivity of succinic anhydride.

[0054] As can be seen from Comparative Example 2, Comparative Example 3, Example 1 and Table 1, if no chelating agent is added to the functional solution, or if the carrier is not subjected to gelation treatment during the preparation of the multi-layer core-shell microsphere carrier, the performance of the multi-layer core-shell microsphere carrier will be reduced, thereby reducing the selectivity and stability of the catalyst for preparing succinic anhydride, and further reducing the maleic anhydride conversion rate and succinic anhydride selectivity in the process of preparing succinic anhydride using the above catalyst.

[0055] According to Comparative Example 4, in combination with the data in Comparative Example 1, Comparative Example 3, Example 1 and Table 1, it can be seen that both the maleic anhydride conversion rate and the succinic anhydride selectivity after being catalyzed by the catalyst of this comparative example are significantly reduced. It is proved that the addition of the chelating agent in the functional solution and the gelation treatment of the carrier in the multi-layer core-shell microsphere carrier have a synergistic effect in improving the selectivity and stability of the catalyst for preparing succinic anhydride, and synergistically improve the maleic anhydride conversion rate and succinic anhydride selectivity in the process of preparing succinic anhydride using the catalyst of the present invention.

[0056] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for preparing succinic anhydride, characterized in that: The following steps are involved: S1: dissolving nickel salt and auxiliary metal salt in water, stirring evenly to obtain an active solution for standby use, wherein the mass concentration of nickel salt in water is 0.18-0.22 mol / L, and the mass concentration of auxiliary metal salt in water is 0.05-0.1 mol / L; S2: placing the multilayer core-shell microsphere carrier in a functional solution for micro-etching treatment, vacuuming to 0.04-0.08 MPa, stirring for 4-6 min, filtering, and drying to obtain a pretreated carrier; S3: placing the pretreated carrier in S2 in the active solution prepared in S1, immersing for 10-20 hours, filtering, drying at 80-120°C for 6-10 hours, and calcining at 450-550°C for 4-5 hours to obtain an active carrier; S4: Place the active carrier in S3 at an air velocity of 2000~3000h -1 The catalyst for preparing succinic anhydride is obtained by heating and reducing the catalyst at 200-400° C. for 2-6 hours under a hydrogen atmosphere.

2. A method for preparing a catalyst for preparing succinic anhydride according to claim 1, characterized in that: The preparation method of the functional solution is as follows: dissolving the chelating agent in a sodium hydroxide aqueous solution to prepare 100 L of a mixed solution, cooling the solution to 3-8° C., adding 20-30 g of carbon nanotubes and 30-50 parts of sodium dodecyl sulfate to the mixed solution, stirring for 10-20 min, and obtaining a functional solution.

3. A method for preparing a catalyst for preparing succinic anhydride according to claim 2, characterized in that: In the preparation of the functional solution, the molar concentration of sodium hydroxide in the mixed solution is 0.4-0.6 mol / L, and the molar concentration of the chelating agent in the mixed solution is 0.08-0.12 mol / L.

4. A method for preparing a catalyst for preparing succinic anhydride according to claim 3, characterized in that: The chelating agent includes sodium hexametaphosphate and / or sodium tripolyphosphate.

5. A method for preparing a catalyst for preparing succinic anhydride according to claim 1, characterized in that: The preparation method of the multilayer core-shell microsphere carrier, The following steps are involved: Q1: Add 1 part of aluminum isopropoxide to 10-15 parts of deionized water by weight, stir evenly, drop 5-10% nitric acid solution, adjust the pH to 1-2, stir for 20-40 minutes, add 0.2-0.3 parts of carboxymethyl cellulose and 0.5-0.8 parts of hexamethylenetetramine, stir for 0.5-1 hour, and obtain aluminum colloid; Q2: Prepare an octanol solution with a mass concentration of 1.5-2% sorbitan trioleate and 10-15% tri-n-octylamine, heat it in a water bath to 70-80°C, add the aluminum gel solution of Q1, stir rapidly for 1-2 hours to obtain a gelled liquid, let it stand for 2-4 hours to obtain gel-cured microspheres; Q3: The gel-cured microspheres are vacuum dried at 80-90°C for 6-10 hours, and then calcined at 500-600°C for 3-4 hours to obtain a multi-layer core-shell microsphere carrier.

6. A method for preparing a catalyst for preparing succinic anhydride according to claim 1, characterized in that: The nickel salt in S1 is one or more of nickel nitrate, nickel chloride, nickel acetate and nickel sulfate.

7. A method for preparing a catalyst for preparing succinic anhydride according to claim 1, characterized in that: The auxiliary metal salt in S1 is any one of cerium nitrate and lanthanum nitrate or a mixture of the two in a mass ratio of 1:

1.

8. A catalyst for preparing succinic anhydride, characterized in that: The method is prepared according to any one of claims 1 to 7.

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