Selective hydrogenation catalyst, preparation method and application thereof

Abstract

The present invention relates to the technical field of catalysts, and provides a selective hydrogenation catalyst, a preparation method thereof, and an application thereof. The selective hydrogenation catalyst of the present invention comprises a carrier and an active component supported on the carrier; the active component comprises Ni element and Pd element. The preparation method of the catalyst is as follows: dispersing an active nickel precursor in water, adding a precipitant, stirring evenly, performing a hydrothermal reaction, and performing post-treatment to obtain a centrifuged product; mixing the centrifuged product with a carrier, ball-milling, forming, and calcining to obtain a calcined product; dispersing an active palladium precursor in water to obtain an active palladium precursor solution, impregnating the calcined product in the active palladium precursor solution, and drying to obtain the catalyst. The catalyst of the present invention has the advantages of high catalytic activity and selectivity, simple preparation process, and low price, and has the potential for industrial application.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts. Further, it relates to a selective hydrogenation catalyst, its preparation method and application. Background Art

[0002] Succinic anhydride, also known as amber anhydride, is an important organic synthesis intermediate and fine chemical raw material, and is widely used in the fields of food, surfactants, coatings, medicine, agriculture, plastics, etc.

[0003] The hydrolysis product of succinic anhydride, succinic acid, is the main raw material for polybutylene succinate biodegradable materials. With the country's emphasis on environmental protection policies and development, the demand for succinic acid is increasing day by day. Correspondingly, the demand for succinic anhydride is also increasing year by year, especially for high-purity succinic anhydride, and the external dependence is relatively high.

[0004] At present, the production methods of succinic anhydride adopted in industry are: biological fermentation method, electrochemical method and maleic anhydride catalytic hydrogenation method. Among them, although the biological fermentation method is environmentally friendly, the production cost of this method is high and the product purity is low, making it difficult to meet the needs of industrial production; the electrochemical method has a small production scale and is difficult to meet the increasing market demand; the maleic anhydride hydrogenation method has the advantages of simple process flow, convenient operation, high equipment utilization rate, low operating cost and high product purity, and is the most efficient process for producing succinic anhydride at present.

[0005] The maleic anhydride molecule has a C=C bond and two C=O bonds. Under certain catalytic conditions, selective hydrogenation of the C=C bond can synthesize succinic anhydride; continued hydrogenation of one of the C=O bonds can synthesize γ-butyrolactone; then hydrogenation of the other C=O bond can synthesize tetrahydrofuran. Thus, deep hydrogenation will reduce the selectivity of succinic anhydride. How to control the selectivity of the hydrogenation reaction at the stage of C=C bond hydrogenation is the most important problem in the preparation of succinic anhydride by maleic anhydride hydrogenation, and it is necessary to find a suitable catalyst to improve the selectivity of succinic anhydride.

[0006] Patent US5616730A discloses a method for preparing succinic anhydride. The catalyst uses SiO2 to support nickel and adds Pd or Pt as an auxiliary agent. In this process condition, the reaction conditions are relatively harsh, the reaction pressure is as high as 15 MPa, and special requirements are needed for the setting and material of the reactor, which limits its large-scale application.

[0007] In the method disclosed in patent EP0691335B1, noble metal Pd is selected as the main active component to prepare the catalyst. Although the hydrogenation selectivity is relatively high, the amount of noble metal accounts for 3.0 - 10.0 wt% of the total weight of the catalyst, which greatly increases the production cost and is difficult to industrialize.

[0008] Patent CN109529850A discloses a preparation method and application of a SiO2-supported Ni catalyst for the hydrogenation of maleic anhydride to produce succinic anhydride. The pressure in the liquid-phase hydrogenation reaction using this catalyst is relatively high (5.0 MPa), and it can only be used for batch synthesis reactions and cannot be applied to continuous large-scale production. Summary of the Invention

[0009] To solve the problems in the prior art, the present invention provides a selective hydrogenation catalyst, its preparation method and application. The catalyst of the present invention has the advantages of high catalyst activity and selectivity, simple preparation process, and low catalyst price, and has the potential for industrial application.

[0010] One object of the present invention is to provide a selective hydrogenation catalyst, wherein the catalyst comprises a carrier and an active component supported on the carrier;

[0011] The active component comprises Ni element and Pd element;

[0012] Based on the total weight of the catalyst being 100%, the loading amounts of Ni element and Pd element are 1.1 - 16 wt%, for example, they can be 1.1 wt%, 1.5 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 5.1 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 9.2 wt%, 10 wt%, 11 wt%, 12 wt%, 12.3 wt%, 13 wt%, 14 wt%, 15 wt%, 15.5 wt%, 16 wt%, and any range composed of any two values; preferably 5.1 - 15.5 wt%, more preferably 9.2 - 12.3 wt%.

[0013] In the present invention, other conventional active metal elements can be added to the catalyst as needed.

[0014] Preferably,

[0015] Based on the total weight of the catalyst being 100%,

[0016] the loading amount of Pd is 0.1 - 1.0 wt%, for example, it can be 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, and any range composed of any two values; preferably 0.1 - 0.5 wt%; more preferably 0.2 - 0.3 wt%; and / or,

[0017] The loading amount of Ni is 1-15 wt%, for example, it can be 1 wt%, 1.5 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, 15 wt%, and any range composed of any two values; preferably 5-15 wt%, more preferably 9-12 wt%.

[0018] Preferably,

[0019] The carrier includes carrier one and carrier two;

[0020] Carrier one is selected from sepiolite; and / or,

[0021] Carrier two is selected from at least one of alumina, silica, and activated carbon;

[0022] Preferably, the mass ratio of carrier one to carrier two is 5:1-1:5. For example, it can be 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, and any range composed of any two values.

[0023] In the present invention, the sepiolite carrier has a fibrous structure and an open porous network, which can endow the catalyst with good catalytic performance. Especially, the composite carrier formed with the alumina carrier makes the catalyst performance better.

[0024] The second object of the present invention is to provide a preparation method of the selective hydrogenation catalyst described in the first object of the present invention. The method includes the following steps:

[0025] (1) Disperse the active nickel precursor in water, add a precipitant, stir evenly, carry out hydrothermal reaction, and perform post-treatment to obtain a centrifuged product;

[0026] (2) After mixing the centrifuged product with the carrier, carry out ball milling, shaping, and calcination to obtain a calcined product;

[0027] (3) Disperse the active palladium precursor in water to obtain an active palladium precursor solution, impregnate the calcined product in the active palladium precursor solution, and dry to obtain the catalyst.

[0028] In the present invention, the post-treatment can adopt existing conventional post-treatment means, such as centrifugation, washing, drying, etc.

[0029] The shaping adopts existing common shaping means, and in the present invention, the extrusion shaping method is adopted.

[0030] Preferably,

[0031] In step (1),

[0032] The active nickel precursor is selected from at least one of soluble nickel salts; preferably at least one of nickel nitrate, nickel sulfate, nickel chloride and nickel acetate; more preferably nickel nitrate; and / or,

[0033] The precipitant is selected from alkaline solubles, preferably at least one of sodium hydroxide, sodium bicarbonate, sodium carbonate, ammonium carbonate or potassium hydroxide.

[0034] Preferably,

[0035] In step (1),

[0036] The mass ratio of the active nickel precursor to the precipitant is 1:2 - 1:3; and / or,

[0037] The mass ratio of the active nickel precursor to water is 8 - 12:1.

[0038] Preferably,

[0039] In step (1),

[0040] The temperature of the hydrothermal reaction is 150 - 220 °C, preferably 150 - 180 °C; the time is 6 - 12 hours.

[0041] In the present invention, drying can be carried out under existing ordinary drying conditions. Preferably, the drying temperature is 80 - 120 °C and the time is 6 - 12 hours.

[0042] Preferably,

[0043] In step (2),

[0044] The mass ratio of the carrier to the centrifuged product is 1:5 - 15;

[0045] It is milled to 20 - 100 mesh;

[0046] The temperature of the roasting is 350 - 650 °C and the time is 2 - 8 hours.

[0047] Preferably,

[0048] In step (3),

[0049] The active palladium precursor is a soluble palladium salt, preferably at least one of Na2PdCl4 and PdCl2; and / or,

[0050] The concentration of the active palladium precursor solution is 0.5 - 5 g / L.

[0051] In the present invention, the impregnation process of the active palladium precursor solution and the calcined product adopts existing conventional impregnation conditions. Preferably, the volume ratio of the active palladium precursor solution to the calcined product is 1:1;

[0052] In the present invention, drying after impregnation adopts existing conventional drying conditions. Preferably, the drying temperature is 80 - 120°C and the time is 6 - 12 hours.

[0053] The third object of the present invention is to provide a method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride, and the method comprises the following steps:

[0054] Contact and react the catalyst described in the first object of the present invention after activation or the catalyst prepared by the preparation method described in the second object of the present invention, hydrogen, and maleic anhydride solution to prepare succinic anhydride;

[0055] Preferably, the reaction pressure of the contact reaction is 1 - 5 MPa, such as 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, and any range formed by any two values; preferably 1 - 3 MPa, more preferably 1 - 1.5 MPa.

[0056] In the present invention, existing conventional process conditions can be adopted for preparing succinic anhydride. Preferably, the above-mentioned catalyst and maleic anhydride solution are simultaneously added to a slurry bed or a suspension bed reactor for reaction; the maleic anhydride solution is a solution formed by dissolving maleic anhydride in an organic solvent; preferably, the organic solvent is selected from at least one of tetrahydrofuran, 1,4 - dioxane, or γ - butyrolactone;

[0057] The concentration of the maleic anhydride solution is 10 - 30 wt%; and / or,

[0058] The mass ratio of the catalyst to maleic anhydride is 0.01 - 0.05:1; and / or,

[0059] The temperature of the contact reaction is 60 - 150°C and the time is 1 - 6 h.

[0060] Compared with the prior art, the present invention has at least the following advantages:

[0061] 1. The active components of the catalyst of the present invention include Ni and Pd, and the catalytic effect of the catalyst is further improved through the special ratio of these two components.

[0062] 2. The amount of precious metal Pd used in the catalyst of the present invention is small, making the overall price of the catalyst low, which is beneficial to industrial application.

[0063] 3. The present invention has changed the traditional catalyst preparation process. First, the NiO active component is prepared by the hydrothermal method, and then it is ball-milled with a specific composite support. Then, the PdO active component is loaded by the impregnation method to prepare a novel Pd-Ni / support catalyst. The active component grains of this supported catalyst are nanoscale, evenly distributed, have more well-dispersed catalytic active centers, and have good anti-coking ability. The preparation process is simple and practical.

[0064] 4. The catalyst of the present invention exhibits good catalytic performance in the hydrogenation of maleic anhydride to succinic anhydride. It can not only react under lower pressure but also realize the continuous large-scale production of succinic anhydride. It is a novel nanocatalyst with potential for industrial application. Specific Embodiments

[0065] The present invention will be specifically described below in conjunction with specific embodiments. It is necessary to point out here that the following embodiments are only used for further illustration of the present invention and cannot be understood as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0066] The raw materials used in the following examples and comparative examples are all commercially available.

[0067] Example 1

[0068] Weigh 100 g of Ni(NO3)2·6H2O and dissolve it in 1000 mL of deionized water. Stir to dissolve, and after it is completely dispersed, add 250 g of KOH. Continue to stir for 10 minutes and then transfer it to a reaction kettle. Heat it by programmed heating to 180 °C and react for 10 hours. After the reaction is completed, perform centrifugal separation, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain the centrifuged product.

[0069] Take 50 g of the above centrifuged product and 341.99 g of sepiolite (Spt) / alumina (mixed support, the mass ratio of sepiolite to alumina is 2:1) and mix and grind them to 60 mesh, form them, and calcine them at 500 °C for 4 hours for later use to obtain the calcined product. Another 0.42 L of Na2PdCl4 is prepared into a solution with a concentration of 2 g / L and impregnated into the above calcined product. After impregnation for 3 hours, it is dried at a constant temperature, and finally, the Pd-Ni / Spt-Al catalyst is obtained.

[0070] In the obtained catalyst, Pd accounts for 0.2 wt% of the catalyst; Ni accounts for 10 wt% of the catalyst; the rest is the sepiolite (Spt) / alumina mixed support.

[0071] After the catalyst was prepared, the catalytic activity was evaluated by the following method: 1.2 g of the activated catalyst and 500 g of a tetrahydrofuran solution with a maleic anhydride content of 15 wt% were simultaneously added to a slurry bed reactor. Under the conditions of a reaction temperature of 70 °C, reaction pressures of 1.5 MPa and 2.5 MPa, and a reaction time of 2 hours, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0072] Example 2

[0073] Weigh an appropriate amount of 125 g of Ni(NO3)2·6H2O and dissolve it in 1000 mL of deionized water. Stir to dissolve it. After it is completely dispersed, add 250 g of NaOH. Continue to stir for 10 minutes and then transfer it to a reaction kettle. Heat it up to 170 °C by programmed heating and react for 10 hours. After the reaction is completed, centrifuge and separate, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain a centrifuged product.

[0074] Take 50 g of the above centrifuged product and 276.34 g of sepiolite (Spt) / alumina (mixed support, the mass ratio of sepiolite to alumina is 1:1) and mix and grind them to 40 mesh, form them, and calcine them at 500 °C for 4 hours for later use to obtain a calcined product. Another 0.50 L of Na2PdCl4 is weighed and made into a solution with a concentration of 3 g / L, impregnated into the above calcined product. After impregnation for 3 hours, it is dried at a constant temperature, and finally a Pd-Ni / Spt-Al catalyst is obtained.

[0075] In the obtained catalyst, Pd accounts for 0.3 wt% of the catalyst; Ni accounts for 12 wt% of the catalyst; the rest is sepiolite (Spt) / alumina mixed support.

[0076] After the catalyst was prepared, the catalyst evaluation method was the same as the reaction conditions at 2.5 MPa in Example 1. After testing, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0077] Example 3

[0078] Weigh 100 g of Ni(CH3COO)2 and dissolve it in 1000 mL of deionized water. Stir to dissolve it. After it is completely dispersed, add 300 g of sodium carbonate. Continue to stir for 10 minutes and then transfer it to a reaction kettle. Heat it up to 150 °C by programmed heating and react for 12 hours. After the reaction is completed, centrifuge and separate, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain a centrifuged product.

[0079] Take 50 g of the above centrifuged product and 785.579 g of sepiolite (Spt) / alumina (mixed carrier, the mass ratio of sepiolite to alumina is 5:1), mix and grind them to 80 mesh, form them, and calcine at 500 °C for 4 hours for later use to obtain the calcined product. Another 0.80 L of Na2PdCl4 is weighed and made into a solution with a concentration of 5 g / L, impregnated into the above calcined product. After impregnation for 3 hours, it is dried at a constant temperature, and finally the Pd-Ni / Spt-Al catalyst is obtained.

[0080] In the obtained catalyst, Pd accounts for 0.5 wt% of the catalyst; Ni accounts for 5 wt% of the catalyst; the rest is the sepiolite (Spt) / alumina mixed carrier.

[0081] After the catalyst is prepared, the catalyst evaluation method is the same as that in Example 1 under the reaction conditions of 2.5 MPa. After detection, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0082] Example 4

[0083] Weigh 83 g of NiCl2·6H2O and dissolve it in 1000 mL of deionized water, stir to dissolve it. After it is completely dispersed, add 200 g of sodium bicarbonate, continue to stir for 10 minutes, and then transfer it to a reaction kettle. Heat it up to 180 °C by programmed heating and react for 10 hours. After the reaction is completed, centrifuge and separate, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain the centrifuged product.

[0084] Take 50 g of the above centrifuged product and 490.98 g of sepiolite (Spt) / alumina (mixed carrier, the mass ratio of sepiolite to alumina is 1:3) and mix and grind them to 20 mesh, form them, and calcine at 500 °C for 5 hours for later use to obtain the calcined product. Another 0.50 L of Na2PdCl4 is weighed and made into a solution with a concentration of 4 g / L, impregnated into the above calcined product. After impregnation for 3 hours, it is dried at a constant temperature, and finally the Pd-Ni / Spt-Al catalyst is obtained.

[0085] In the obtained catalyst, Pd accounts for 0.4 wt% of the catalyst; Ni accounts for 8 wt% of the catalyst; the rest is the sepiolite (Spt) / alumina mixed carrier.

[0086] After the catalyst is prepared, the catalyst evaluation method is the same as that in Example 1 under the reaction conditions of 2.5 MPa. After detection, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0087] Example 5

[0088] Weigh 100 g of NiSO4·6H2O and dissolve it in 1000 mL of deionized water. Stir to dissolve. After it is completely dispersed, add 225 g of KOH. Continue to stir for 10 minutes and then transfer it to a reaction kettle. Heat it with programmed temperature rise to 180 °C and react for 10 hours. After the reaction is completed, centrifuge and separate, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain the centrifuged product.

[0089] Take 50 g of the above centrifuged product and 211.6 g of sepiolite (Spt) / aluminum oxide (mixed carrier, the mass ratio of sepiolite to aluminum oxide is 1:5) and mix and grind them to 60 mesh, form them, and calcine them at 500 °C for 4 hours for later use to obtain the calcined product. Another 0.27 L of Na2PdCl4 is weighed and made into a solution with a concentration of 1 g / L, impregnated into the above calcined product. After impregnation for 3 hours, dry it at a constant temperature, and finally obtain the Pd-Ni / Spt-Al catalyst.

[0090] In the obtained catalyst, Pd accounts for 0.1 wt% of the catalyst; Ni accounts for 15 wt% of the catalyst; the rest is the sepiolite (Spt) / aluminum oxide mixed carrier.

[0091] After the catalyst is prepared, the catalyst evaluation method is the same as that in Example 1 under the reaction conditions of 2.5 MPa. After detection, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0092] Example 6

[0093] Weigh 100 g of Ni(NO3)2·6H2O and dissolve it in 1000 mL of deionized water. Stir to dissolve. After it is completely dispersed, add 250 g of KOH. Continue to stir for 10 minutes and then transfer it to a reaction kettle. Heat it with programmed temperature rise to 220 °C and react for 6 hours. After the reaction is completed, centrifuge and separate, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain the centrifuged product.

[0094] Take 50 g of the above centrifuged product and 385.56 g of sepiolite (Spt) / aluminum oxide (mixed carrier, the mass ratio of sepiolite to aluminum oxide is 1:2) and mix and grind them to 60 mesh, form them, and calcine them at 500 °C for 4 hours for later use to obtain the calcined product. Another 0.46 L of Na2PdCl4 is weighed and made into a solution with a concentration of 2 g / L, impregnated into the above calcined product. After impregnation for 3 hours, dry it at a constant temperature, and finally obtain the Pd-Ni / Spt-Al catalyst.

[0095] In the obtained catalyst, Pd accounts for 0.2 wt% of the catalyst; Ni accounts for 9 wt% of the catalyst; the rest is the sepiolite (Spt) / aluminum oxide mixed carrier.

[0096] After the catalyst was prepared, the catalyst evaluation method was the same as that in Example 1 under the reaction conditions at 2.5 MPa. After detection, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0097] Example 7

[0098] Weigh 100 g of Ni(NO3)2·6H2O and dissolve it in 1000 mL of deionized water, stir to dissolve. After it is completely dispersed, add 250 g of KOH, continue to stir for 10 minutes, then transfer it to a reaction kettle, heat it by programmed temperature rise to 180 °C and react for 4 hours. After the reaction is completed, perform centrifugal separation, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain a centrifuged product.

[0099] Take 50 g of the above centrifuged product and 276.34 g of sepiolite (Spt) / activated carbon (mixed carrier, the mass ratio of sepiolite to / activated carbon is 1:1) and mix and grind them to 100 mesh, form them, and calcine them at 650 °C for 2 hours for later use to obtain a calcined product. Separately, weigh 0.50 L of Na2PdCl4 and prepare a solution with a concentration of 3 g / L, impregnate it into the above calcined product, after impregnation for 3 hours, dry it at a constant temperature, and finally obtain a Pd-Ni / Spt-S catalyst.

[0100] In the obtained catalyst, Pd accounts for 0.3 wt% of the catalyst; Ni accounts for 12 wt% of the catalyst; the rest is the sepiolite (Spt) / activated carbon mixed carrier.

[0101] After the catalyst was prepared, the catalyst evaluation method was the same as that in Example 1 under the reaction conditions at 2.5 MPa. After detection, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0102] Example 8

[0103] Weigh 100 g of Ni(NO3)2·6H2O and dissolve it in 1000 mL of deionized water, stir to dissolve. After it is completely dispersed, add 250 g of KOH, continue to stir for 10 minutes, then transfer it to a reaction kettle, heat it by programmed temperature rise to 180 °C and react for 4 hours. After the reaction is completed, perform centrifugal separation, and then wash it with deionized water until the pH value of the filtrate is neutral. The product is dried at 110 °C for 12 hours to obtain a centrifuged product.

[0104] Take 50 g of the above centrifuged product and 276.34 g of sepiolite (Spt) / silica (mixed carrier, the mass ratio of sepiolite to silica is 1:1) and mix and grind them to 80 mesh, form them, and calcine them at 450 °C for 5 hours for later use to obtain a calcined product. Separately, weigh 0.50 L of Na2PdCl4 and prepare a solution with a concentration of 3 g / L, impregnate it into the above calcined product, after impregnation for 3 hours, dry it at a constant temperature, and finally obtain a Pd-Ni / Spt-S catalyst.

[0105] In the obtained catalyst, Pd accounts for 0.3 wt% of the catalyst; Ni accounts for 12 wt% of the catalyst; the rest is the sepiolite (Spt) / silica mixed support.

[0106] After the catalyst is prepared, the catalyst evaluation method is the same as the reaction conditions in Example 1 under 2.5 MPa. After testing, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0107] Comparative Example 1

[0108] Replace the support in Example 1 with pure aluminum powder for the mixed support, and change the precipitation temperature of the nickel precursor to 60 °C, with the other parameters remaining unchanged.

[0109] After the catalyst is prepared, the catalyst evaluation method is the same as the reaction conditions in Example 1 under 2.5 MPa. After testing, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0110] Comparative Example 2

[0111] Replace the support in Example 2 with pure silicon powder for the mixed support, and change the precipitation temperature of the nickel precursor to 60 °C, with the other parameters remaining unchanged.

[0112] After the catalyst is prepared, the catalyst evaluation method is the same as the reaction conditions in Example 1 under 2.5 MPa. After testing, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0113] Comparative Example 3

[0114] Change the precipitation temperature of the nickel precursor in Example 1 to 60 °C, with the other parameters remaining unchanged.

[0115] After the catalyst is prepared, the catalyst evaluation method is the same as the reaction conditions in Example 1 under 2.5 MPa. After testing, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0116] Comparative Example 4

[0117] Replace the alumina support in Example 1 with the same mass of sepiolite, with the other parameters remaining unchanged.

[0118] After the catalyst is prepared, the catalyst evaluation method is the same as the reaction conditions in Example 1 under 2.5 MPa. After testing, the conversion rate of maleic anhydride and the selectivity of succinic anhydride are shown in Table 1.

[0119] Table 1 Comparison table of catalyst performance

[0120] Catalyst Maleic anhydride conversion rate (%) Succinic anhydride selectivity (%) Example 1 (2.5 MPa) 100 99.60 Example 1 (1.5 MPa) 100 99.30 Example 2 (2.5 MPa) 100 98.50 Example 3 (2.5 MPa) 99.20 99.00 Example 4 (2.5 MPa) 100 98.90 Example 5 (2.5 MPa) 98.60 98.50 Example 6 (2.5 MPa) 99.60 99.10 Example 7 (2.5 MPa) 99.30 99.00 Example 8 (2.5 MPa) 98.90 99.10 Comparative Example 1 (2.5 MPa) 97.10 95.60 Comparative Example 2 (2.5 MPa) 98.60 97.60 Comparative Example 3 (2.5 MPa) 97.60 98.00 Comparative Example 4 (2.5 MPa) 98.30 98.10

[0121] As can be seen from Table 1, the catalyst prepared in the embodiment of the present invention has better maleic anhydride conversion rate and succinic anhydride selectivity than the catalyst prepared in the comparative example. In particular, in Example 1 of the present invention, with the composite support of sepiolite and alumina and a specific Pd and Ni ratio, the performance of the corresponding prepared catalyst is the best.

[0122] The catalyst prepared in the embodiment of the present invention requires a small reaction pressure, has low requirements for production equipment, and ensures production safety.

[0123] Compared with the catalyst prepared in the comparative example, the catalyst prepared in the embodiment of the present invention has improved maleic anhydride conversion rate and succinic anhydride selectivity. In particular, the improvement of succinic anhydride selectivity is of great significance in industrial production. First, it can increase the yield of succinic anhydride and improve economic efficiency; second, the improvement of succinic anhydride selectivity can improve the purity of succinic anhydride products, save the subsequent purification process of succinic anhydride products, and effectively reduce costs.

[0124] The above has described the embodiments of the present invention. The above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for the liquid-phase hydrogenation of maleic anhydride to succinic anhydride, characterized in that, The method includes the following steps: Contact the activated catalyst, hydrogen, and maleic anhydride solution for a reaction to prepare succinic anhydride; The catalyst described above includes a carrier and an active component supported on the carrier; The active component includes Ni element and Pd element; Based on the total weight of the catalyst being 100%, The loading amount of Pd is 0.2 - 0.4 wt%; The loading amount of Ni is 9 - 12 wt%; The carrier includes Carrier 1 and Carrier 2; Carrier 1 is selected from sepiolite; Carrier 2 is selected from at least one of alumina, silica, and activated carbon; The preparation method of the catalyst described above includes the following steps: (1) Disperse the active nickel precursor in water, add a precipitant, stir evenly, conduct a hydrothermal reaction, and perform post-treatment to obtain a centrifuged product; (2) After mixing the centrifuged product with the carrier, conduct ball milling, forming, and calcination to obtain a calcined product; (3) Disperse the active palladium precursor in water to obtain an active palladium precursor solution, immerse the calcined product in the active palladium precursor solution, and dry to obtain the catalyst.

2. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, wherein: Based on the total weight of the catalyst being 100%, The loading amount of Pd is 0.2 - 0.3 wt%.

3. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, wherein: The mass ratio of Carrier 1 to Carrier 2 is 5:1 - 1:

5.

4. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, wherein, In step (1), The active nickel precursor is selected from at least one of soluble nickel salts; and / or, The precipitant is selected from alkaline soluble substances.

5. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 4, wherein, In step (1), The active nickel precursor is at least one of nickel nitrate, nickel sulfate, nickel chloride, and nickel acetate; and / or, The precipitant is at least one of sodium hydroxide, sodium bicarbonate, sodium carbonate, ammonium carbonate, or potassium hydroxide.

6. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, wherein, In step (1), The mass ratio of the active nickel precursor to the precipitant is 1:2 - 1:3; and / or, The mass ratio of the active nickel precursor to water is 8 - 12:

1.

7. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, wherein, In step (1), The temperature of the hydrothermal reaction is 150 - 220 °C, and the time is 6 - 12 hours.

8. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 7, wherein, In step (1), The temperature of the hydrothermal reaction is 150 - 180 °C.

9. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, wherein, In step (2), The mass ratio of the carrier to the centrifuged product is 1:5 - 15; Ball mill to 20 mesh to 100 mesh; The temperature of the calcination is 350 - 650 °C, and the time is 2 - 8 hours.

10. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, wherein, In step (3), The active palladium precursor is a soluble palladium salt; and / or, The concentration of the active palladium precursor solution is 0.5-5 g / L.

11. The method for producing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 10, characterized in that, In step (3), The active palladium precursor is at least one of Na2PdCl4 and PdCl2.

12. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 1, characterized in that, The pressure of the contact reaction is 1-5 MPa.

13. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 12, wherein, The pressure of the contact reaction is 1-3 MPa.

14. The method for preparing succinic anhydride by liquid-phase hydrogenation of maleic anhydride according to claim 13, characterized in that, The pressure of the contact reaction is 1-1.5 MPa.