Method for preparing succinic anhydride based on honeycomb powder nickel-molybdenum catalyst

Abstract

The present invention belongs to the technical field of heterocyclic compounds, and particularly relates to a method for preparing succinic anhydride based on a honeycomb powder nickel-molybdenum catalyst. The honeycomb powder nickel-molybdenum catalyst, maleic anhydride, a solvent and hydrogen are mixed and then enter a tubular reactor for a hydrogenation reaction, followed by crystallization separation to obtain succinic anhydride. The present invention maintains the high activity and high stability of the catalyst, enhances the mass transfer efficiency of the gas-liquid-solid three-phase, and greatly reduces the energy consumption by using crystallization separation.

Description

Technical Field

[0001] The present invention belongs to the technical field of heterocyclic compounds, and particularly relates to a method for preparing succinic anhydride based on a honeycomb powder nickel-molybdenum catalyst. Background Art

[0002] Succinic anhydride is an important fine chemical intermediate, which is widely used in industries such as medicine, agriculture, food, and petrochemical industry. The maleic anhydride hydrogenation method is a method for directly hydrogenating maleic anhydride to prepare succinic anhydride, which has the advantages of simple process flow, convenient operation process, high equipment utilization rate, low production cost, and high product purity. The maleic anhydride hydrogenation method selectively hydrogenates the C=C bond or C=O bond through gas-phase or liquid-phase hydrogenation to synthesize succinic anhydride (SAA), γ-butyrolactone (GBL), tetrahydrofuran (THF), 1,4-butanediol (BDO), etc. Using different catalysts will result in differences in the products and their distributions of the maleic anhydride hydrogenation reaction. Therefore, the catalyst and the synthesis method are the key factors in the catalytic hydrogenation process.

[0003] In the prior art, there are many reports on the process for preparing succinic anhydride by hydrogenating maleic anhydride. US Patent No. US5952514A discloses a catalyst pressed from iron, aluminum, silicon, titanium, and carbon alloy powders under the conditions of a temperature of 60-180°C and a pressure of 38 MPa, and a hydrogenation experiment was carried out using a fixed bed to prepare succinic anhydride. Although the yield of succinic anhydride is above 99%, its reaction pressure is too high, which is not conducive to large-scale production.

[0004] Chinese Patent No. CN103570650A discloses a process flow for continuously producing succinic anhydride and co-producing succinic acid by hydrogenating maleic anhydride. After maleic anhydride is dissolved in a solvent, a hydrogenation reaction is carried out in two-stage reactors by the catalytic action of a silica-alumina heterogeneous catalyst, and finally the solvent is separated by distillation. The distillation method consumes a large amount of energy, greatly increasing the reaction cost.

[0005] At present, the hydrogenation process of maleic anhydride includes batch hydrogenation process and continuous hydrogenation process. The batch hydrogenation process has disadvantages such as long reaction cycle and unstable product quality; while the continuous hydrogenation process avoids the above problems, but similar to the batch hydrogenation process, the continuous hydrogenation process also has the problem of low gas-liquid-solid mass transfer efficiency. Summary of the Invention

[0006] The object of the present invention is to provide a method for preparing succinic anhydride based on a honeycomb powder nickel-molybdenum catalyst, which maintains the high activity and high stability of the catalyst, enhances the gas-liquid-solid mass transfer efficiency, and greatly reduces the energy consumption by crystallization separation.

[0007] The method for preparing succinic anhydride based on a honeycomb powder nickel-molybdenum catalyst according to the present invention is that the honeycomb powder nickel-molybdenum catalyst, maleic anhydride, a solvent, and hydrogen are mixed and then enter a tubular reactor for a hydrogenation reaction, followed by crystallization and separation to obtain succinic anhydride;

[0008] Among them, the preparation method of the honeycomb powder nickel-molybdenum catalyst includes the following steps:

[0009] (a) Mix nickel nitrate hexahydrate, ammonium molybdate, sodium silicate nonahydrate, urea, and PEG6000, and then add deionized water for high-speed shearing to obtain a suspension containing precipitates;

[0010] (b) Filter the suspension containing precipitates to obtain precipitates; after washing the precipitates to neutrality, add deionized water for dispersion, and subject the obtained dispersion to spray granulation to obtain a catalyst precursor; calcine the catalyst precursor, reduce it in a hydrogen atmosphere, and passivate it to obtain a honeycomb powder nickel-molybdenum catalyst.

[0011] In step (a), the mass ratio of nickel nitrate hexahydrate, ammonium molybdate, sodium silicate nonahydrate, urea, PEG6000, and deionized water is 1:0.016 - 0.02:0.5 - 0.8:0.8 - 1.2:0.02 - 0.04:10 - 30.

[0012] In step (a), the high-speed shearing rate is 800 - 2000 rpm, the high-speed shearing temperature is 60 - 120 °C, and the high-speed shearing time is 12 - 36 h.

[0013] In step (b), the mass ratio of the precipitate to deionized water is 1:10 - 12; the spray granulation pressure is 0.15 - 0.3 MPa, and the spray granulation temperature is 120 - 180 °C; the calcination temperature is 450 - 650 °C, and the calcination time is 3 - 4 h; the reduction temperature is 500 - 700 °C, and the reduction time is 3 - 4 h; passivation is carried out with N containing 0.5 - 2 wt.% O 2 at room temperature for 3 - 4 h. 2 The mass of the honeycomb powder nickel-molybdenum catalyst is 2 - 6% of the mass of maleic anhydride.

[0014] The solvent is acetic acid, and the mass ratio of the solvent to maleic anhydride is 2 - 8:1.

[0015] The mass ratio of maleic anhydride to hydrogen is 1:800 - 1200.

[0016] The hydrogenation reaction temperature is 80 - 140 °C, the hydrogenation reaction pressure is 0.5 - 3 MPa, and the hydrogenation reaction time is 30 - 180 min.

[0017] The crystallization temperature is 20 - 25 °C, and the crystallization time is 3 - 5 min.

[0018] The crystallization temperature is 20 - 25 °C, and the crystallization time is 3 - 5 min.

[0019] The device used in the method for preparing succinic anhydride based on a honeycomb powder nickel-molybdenum catalyst includes a hydrogen gas cylinder. The hydrogen gas cylinder, premixing kettle, hydraulic pump, tubular reactor, catalyst filter, crystallization tank, succinic anhydride filter, and product succinic anhydride storage tank are connected in sequence. The premixing kettle is connected to a static mixer, and the static mixer is respectively connected to a solvent storage tank, a maleic anhydride storage tank, and a catalyst storage tank. The solvent storage tank is connected to the succinic anhydride filter, and the catalyst storage tank is connected to the catalyst filter.

[0020] The size range of the honeycomb powder nickel-molybdenum catalyst prepared by the present invention is 800 - 1200 nm.

[0021] In the present invention, the honeycomb powder nickel-molybdenum catalyst, solvent acetic acid, and maleic anhydride are mixed through a static mixer and then enter the premixing kettle to be mixed with hydrogen to obtain a mixed material. The hydraulic pump is used to pump the mixed material into the tubular reactor, where the gas-liquid-solid three phases are fully mixed to carry out a hydrogenation reaction to obtain the maleic anhydride hydrogenation product succinic anhydride. Based on the fact that the solubility of succinic anhydride in acetic acid varies greatly with temperature, the product succinic anhydride is separated by crystallization, and the solvent is recycled.

[0022] The beneficial effects of the present invention are as follows:

[0023] (1) In the honeycomb powder nickel-molybdenum catalyst of the present invention, the second metal Mo is doped. Introducing Mo can adjust the d-band center of Ni to make it closer to the Fermi level, thereby optimizing the adsorption ability of the honeycomb powder nickel-molybdenum catalyst for H, improving the activity of the catalyst, and can cooperate with Ni to adjust the electronic structure of the catalyst, and then can effectively regulate the adsorption behavior of reactants, and improve the selectivity of the catalyst for the C=C double bond.

[0024] (2) The present invention synthesizes a micro-nano particle catalyst with a honeycomb structure by utilizing the synergistic effect of PEG6000, high-speed shearing, and spray drying. Compared with PEG2000 or PEG8000, the specific molecular weight of PEG6000 (chain length about 13.6 nm) precisely matches the hydrolysis kinetics of nickel ions: the moderate molecular chain length of PEG6000 can not only guide the catalyst raw materials to form a stable three-dimensional honeycomb structure through a hydrogen bond network, but also will not cause the structure to collapse due to too short chain segments (PEG2000) or too high solution viscosity due to too long chain segments (PEG8000), which hinders high-speed shear dispersion. The high shear rate field generated by high-speed shearing acts synergistically with PEG6000. On the one hand, it eliminates the local concentration gradient through instantaneous uniform mixing, enabling the catalyst precursor to grow directionally under the guidance of PEG6000. On the other hand, it strips the metal species adsorbed on the surface of the PEG6000 molecular chain by means of shear-induced micro-vortices, avoiding the phenomenon of active site embedding. The lower crystallinity of PEG6000 ensures that the metastable honeycomb structure remains after the shearing action terminates. Using the spray drying method, catalysts with a smaller bulk density can be synthesized at a certain temperature and pressure, and caking during the drying process can be prevented.

[0025] (3) The honeycomb structure in the honeycomb powder nickel-molybdenum catalyst has a large specific surface area (450 - 480 m 2 / g), providing a larger contact area for the catalyst, enabling maleic anhydride to diffuse more easily to the surface of the active substance, thereby increasing the speed and efficiency of the catalytic reaction. The catalyst can be easily stored in air by using the passivation method.

[0026] (4) During the gas-liquid-solid three-phase transfer process, the micro-nano particle catalyst is better dispersed in the reaction system. The honeycomb structure increases the contact area with hydrogen and maleic anhydride and has high stability, promoting hydrogen adsorption and maleic anhydride activation, thereby increasing the hydrogenation reaction rate.

[0027] (5) The present invention separates the product by crystallization. Utilizing the solubility characteristics of succinic anhydride in acetic acid, the solubility of succinic anhydride in acetic acid is greatly affected by temperature. At room temperature, more than 95% of succinic anhydride can crystallize out, greatly reducing the energy consumption of separating the product by distillation.

[0028] (6) The present invention adopts a continuous hydrogenation process. By continuously adding maleic anhydride, acetic acid, and the catalyst, the concentration balance of the C=C double bond of maleic anhydride in the reaction process is ensured, guaranteeing the activity of the catalyst, increasing the hydrogenation efficiency, reducing the reaction time, and saving energy consumption. Description of the Drawings

[0029] Figure 1Schematic structural diagram of the device used in the method for preparing succinic anhydride based on honeycomb powder nickel-molybdenum catalyst in the present invention; in the figure: 1, hydrogen cylinder; 2, solvent storage tank; 3, maleic anhydride storage tank; 4, catalyst storage tank; 5, static mixer; 6, premixing kettle; 7, hydraulic pump; 8, tubular reactor; 9, catalyst filter; 10, crystallization tank; 11, succinic anhydride filter; 12, product succinic anhydride storage tank.

[0030] Figure 2 SEM image of the honeycomb powder nickel-molybdenum catalyst prepared in Example 1.

[0031] Figure 3 EDS image of the honeycomb powder nickel-molybdenum catalyst prepared in Example 1.

[0032] Figure 4 Particle size distribution diagram of the honeycomb powder nickel-molybdenum catalyst prepared in Example 1.

[0033] Figure 5 SEM image of the catalyst prepared in Comparative Example 1.

[0034] Figure 6 SEM image of the catalyst prepared in Comparative Example 2.

[0035] Figure 7 SEM image of the catalyst prepared in Comparative Example 5.

[0036] Figure 8 SEM image of the catalyst prepared in Comparative Example 6. Detailed implementation manners

[0037] The following further describes the present invention in conjunction with examples.

[0038] Example 1

[0039] As Figure 1 shown, the device used in the method for preparing succinic anhydride based on honeycomb powder nickel-molybdenum catalyst includes a hydrogen cylinder 1, and the hydrogen cylinder 1, premixing kettle 6, hydraulic pump 7, tubular reactor 8, catalyst filter 9, crystallization tank 10, succinic anhydride filter 11 and product succinic anhydride storage tank 12 are connected in sequence. The premixing kettle 6 is connected to the static mixer 5, and the static mixer 5 is respectively connected to the solvent storage tank 2, maleic anhydride storage tank 3 and catalyst storage tank 4. The solvent storage tank 2 is connected to the succinic anhydride filter 11, and the catalyst storage tank 4 is connected to the catalyst filter 9.

[0040] The preparation method of the honeycomb powder nickel-molybdenum catalyst includes the following steps:

[0041] (a) Mix 10 g of nickel nitrate hexahydrate, 0.184 g of ammonium molybdate, 6 g of sodium silicate nonahydrate, 10 g of urea, and 0.2 g of PEG6000. Then add 300 g of deionized water and perform high-speed shearing at 90 °C and 1200 rpm for 20 h to obtain a suspension containing precipitates.

[0042] (b) Filter the suspension containing precipitates to obtain the precipitates. After washing the precipitates to neutrality, add deionized water for dispersion. The mass ratio of the precipitates to deionized water is 1:10. The resulting dispersion is spray granulated to obtain the catalyst precursor. The pressure of spray granulation is 0.3 MPa, and the temperature of spray granulation is 120 °C. Calcinate the catalyst precursor at 600 °C for 4 h and reduce it at 600 °C in a hydrogen atmosphere for 4 h. Passivate it with N containing 1 wt.% O 2 at 2 room temperature for 3.5 h to obtain the honeycomb-shaped powder nickel molybdenum catalyst.

[0043] The SEM image of the honeycomb-shaped powder nickel molybdenum catalyst is shown in Figure 2 The EDS analysis results of the honeycomb-shaped powder nickel molybdenum catalyst are shown in Figure 3 and Table 1. The particle size distribution diagram of the honeycomb-shaped powder nickel molybdenum catalyst is shown in Figure 4 The average size of the honeycomb-shaped powder nickel molybdenum catalyst is 1000 nm, and its specific surface area is measured to be 469.4 m 2 / g.

[0044]

[0045] A method for preparing succinic anhydride based on the honeycomb-shaped powder nickel molybdenum catalyst includes the following steps:

[0046] Before the hydrogenation reaction, purge the entire device with nitrogen to ensure that the device is filled with nitrogen. 0.04 g / min of the honeycomb-shaped powder nickel molybdenum catalyst, 8 g / min of acetic acid, and 1 g / min of maleic anhydride enter the static mixer 5 for mixing, and then enter the premixing kettle 6 to be mixed with 1000 g / min of hydrogen. The resulting mixed material enters the tubular reactor 8 through the hydraulic pump 7 for the hydrogenation reaction. The temperature of the hydrogenation reaction is 80 °C, the pressure of the hydrogenation reaction is 1 MPa, and the time of the hydrogenation reaction is 60 min. After the resulting reaction material passes through the catalyst filter 9 to filter out the catalyst, a liquid material is obtained. The liquid material enters the crystallization tank 10 to crystallize at 20 °C for 5 min. The resulting crystalline material enters the succinic anhydride filter 11 for filtration. The obtained succinic anhydride enters the product succinic anhydride storage tank 12, and the remaining liquid (containing a small amount of maleic anhydride and succinic anhydride) returns to the solvent storage tank 2 for recycling.

[0047] The liquid material obtained after filtering out the catalyst by the catalyst filter 9 was subjected to gas chromatography testing. Chromatographic conditions: Agilent HP-5 chromatographic column, inlet temperature 240 °C, FID detector temperature 240 °C, column flow rate 1 ml / min, hydrogen flow rate 30 ml / min, air flow rate 400 ml / min, and the programmed temperature rise mode was: hold at 80 °C for 2 min, then rise to 220 °C at a rate of 15 °C / min and hold for 15 min. The gas chromatography test results of 6 cycles of the reaction are shown in Table 2. It can be seen from Table 2 that both the maleic anhydride conversion rate and the succinic anhydride selectivity remain at a relatively high level after 6 cycles of the reaction, indicating that the honeycomb powder nickel-molybdenum catalyst has good stability.

[0048]

[0049] Example 2

[0050] The device used for the method of preparing succinic anhydride based on the honeycomb powder nickel-molybdenum catalyst is the same as that in Example 1.

[0051] The preparation method of the honeycomb powder nickel-molybdenum catalyst includes the following steps:

[0052] (a) Mix 10 g of nickel nitrate hexahydrate, 0.16 g of ammonium molybdate, 5 g of sodium silicate nonahydrate, 12 g of urea, and 0.3 g of PEG6000, then add 100 g of deionized water, and perform high-speed shearing at 60 °C and 800 rpm for 36 h to obtain a suspension containing precipitates;

[0053] (b) Filter the suspension containing precipitates to obtain precipitates; after washing the precipitates to neutrality, add deionized water for dispersion, and the mass ratio of the precipitates to deionized water is 1:11. The obtained dispersion is subjected to spray granulation to obtain a catalyst precursor, the pressure of spray granulation is 0.2 MPa, and the temperature of spray granulation is 150 °C; the catalyst precursor is calcined at 450 °C for 3 h, reduced at 500 °C in a hydrogen atmosphere for 3 h, and passivated at room temperature for 3 h with N containing 0.5 wt.% O 2 of 2 to obtain the honeycomb powder nickel-molybdenum catalyst.

[0054] The method of preparing succinic anhydride based on the honeycomb powder nickel-molybdenum catalyst includes the following steps:

[0055] Before the hydrogenation reaction, purge the entire device with nitrogen to ensure that the device is filled with nitrogen; 0.06 g / min of honeycomb powder nickel molybdenum catalyst, 6 g / min of acetic acid and 1 g / min of maleic anhydride enter the static mixer 5 for mixing, and then enter the premixing kettle 6 to be mixed with 1200 g / min of hydrogen. The obtained mixed material enters the tubular reactor 8 through the hydraulic pump 7 for hydrogenation reaction. The hydrogenation reaction temperature is 140 °C, the hydrogenation reaction pressure is 0.5 MPa, and the hydrogenation reaction time is 30 min. After the obtained reaction material is filtered by the catalyst filter 9 to remove the catalyst, a liquid material is obtained. The liquid material enters the crystallization tank 10 to crystallize at 25 °C for 3 min. The obtained crystalline material enters the succinic anhydride filter 11 for filtration. The obtained succinic anhydride enters the product succinic anhydride storage tank 12, and the remaining liquid (containing a small amount of maleic anhydride and succinic anhydride) returns to the solvent storage tank 2 for recycling.

[0056] Perform gas chromatography testing on the liquid material obtained after filtering the catalyst by the catalyst filter 9. Chromatographic conditions: Agilent HP-5 chromatographic column, inlet temperature 240 °C, FID detector temperature 240 °C, column flow rate 1 ml / min, hydrogen flow rate 30 ml / min, air flow rate 400 ml / min. The programmed temperature rise method is: hold at 80 °C for 2 min, then rise to 220 °C at a rate of 15 °C / min and hold for 15 min. The gas chromatography test results of 6 cycles of the reaction are shown in Table 3.

[0057]

[0058] Example 3

[0059] The device used for the method of preparing succinic anhydride based on the honeycomb powder nickel molybdenum catalyst is the same as that in Example 1.

[0060] The preparation method of the honeycomb powder nickel molybdenum catalyst includes the following steps:

[0061] (a) Mix 10 g of nickel nitrate hexahydrate, 0.2 g of ammonium molybdate, 8 g of sodium silicate nonahydrate, 8 g of urea and 0.4 g of PEG6000, then add 200 g of deionized water, and perform high-speed shearing at 120 °C and 2000 rpm for 12 h to obtain a suspension containing precipitates;

[0062] (b) Filter the suspension containing precipitates to obtain precipitates; after washing the precipitates to neutrality, add deionized water for dispersion. The mass ratio of the precipitates to deionized water is 1:12. The obtained dispersion is spray granulated to obtain a catalyst precursor. The pressure of spray granulation is 0.15 MPa, and the temperature of spray granulation is 180 °C; the catalyst precursor is calcined at 650 °C for 3.5 h and reduced at 700 °C in a hydrogen atmosphere for 3.5 h. Use N containing 2 wt.% O 2 of 2Passivate at room temperature for 4 h to obtain a honeycomb powder nickel-molybdenum catalyst.

[0063] A method for preparing succinic anhydride based on the honeycomb powder nickel-molybdenum catalyst includes the following steps:

[0064] Before the hydrogenation reaction, purge the entire device with nitrogen to ensure that the device is filled with nitrogen; 0.02 g / min of the honeycomb powder nickel-molybdenum catalyst, 2 g / min of acetic acid, and 1 g / min of maleic anhydride enter the static mixer 5 for mixing, and then enter the premixing kettle 6 to be mixed with 800 g / min of hydrogen. The obtained mixed material enters the tubular reactor 8 through the hydraulic pump 7 for the hydrogenation reaction. The hydrogenation reaction temperature is 120 °C, the hydrogenation reaction pressure is 3 MPa, and the hydrogenation reaction time is 180 min. After the obtained reaction material is filtered through the catalyst filter 9 to remove the catalyst, a liquid material is obtained. The liquid material enters the crystallization tank 10 to crystallize at 23 °C for 4 min. The obtained crystalline material enters the succinic anhydride filter 11 for filtration. The obtained succinic anhydride enters the product succinic anhydride storage tank 12, and the remaining liquid (containing a small amount of maleic anhydride and succinic anhydride) returns to the solvent storage tank 2 for recycling.

[0065] Perform gas chromatography testing on the liquid material obtained after filtering off the catalyst through the catalyst filter 9. Chromatographic conditions: Agilent HP-5 chromatographic column, inlet temperature 240 °C, FID detector temperature 240 °C, column flow rate 1 ml / min, hydrogen flow rate 30 ml / min, air flow rate 400 ml / min. The programmed temperature rise method is: hold at 80 °C for 2 min, then rise to 220 °C at a rate of 15 °C / min and hold for 15 min. The gas chromatography test results of 6 cycles of the reaction are shown in Table 4.

[0066]

[0067] Comparative Example 1

[0068] In step (a), high-speed shearing was not carried out, and other steps were the same as in Example 1. The SEM diagram of the obtained catalyst is shown in Figure 5 , from Figure 5 it can be seen that the obtained catalyst is not a honeycomb structure, and its measured specific surface area is 311.7 m 2 / g. The gas chromatography test results of 6 cycles of the reaction are shown in Table 5. It can be seen from Table 5 that compared with Example 1, in Comparative Example 1, the maleic anhydride conversion rate decreases rapidly with the increase in the number of reaction cycles, indicating that the catalyst stability of Comparative Example 1 is poor, and the succinic anhydride selectivity of Comparative Example 1 is lower than that of Example 1.

[0069]

[0070] Comparative Example 2

[0071] PEG6000 is not added in step (a), and other steps are the same as those in Example 1. The SEM image of the obtained catalyst is shown in Figure 6 , and it can be seen from Figure 6 that the obtained catalyst is not a honeycomb structure, and its measured specific surface area is 218.0 m 2 / g. The gas chromatography test results for 6 cycles of reaction are shown in Table 6. It can be seen from Table 6 that, compared with Example 1, the maleic anhydride conversion rate of Comparative Example 2 decreases rapidly with the increase in the number of reaction cycles, and the selectivity of succinic anhydride in Comparative Example 2 is lower than that in Example 1; this shows that the catalyst in Comparative Example 2 is not stable enough and has poor selectivity.

[0072]

[0073] Comparative Example 3

[0074] Ammonium molybdate is not added in step (a), and other steps are the same as those in Example 1. The gas chromatography test results for 6 cycles of reaction are shown in Table 7. It can be seen from Table 7 that, compared with Example 1, the selectivity of succinic anhydride in Comparative Example 3 is lower than that in Example 1, indicating that the catalyst in Comparative Example 3 has poor selectivity.

[0075]

[0076] Comparative Example 4

[0077] Spray granulation is not carried out in step (b), and other steps are the same as those in Example 1. The gas chromatography test results for 6 cycles of reaction are shown in Table 8. It can be seen from Table 8 that, compared with Example 1, the maleic anhydride conversion rate of Comparative Example 4 decreases rapidly with the increase in the number of reaction cycles, indicating that the catalyst in Comparative Example 4 has poor stability.

[0078]

[0079] Comparative Example 5

[0080] PEG6000 is replaced by PEG2000 in step (a), and other steps are the same as those in Example 1. The SEM image of the obtained catalyst is shown in Figure 7 , and it can be seen from Figure 7 that the obtained catalyst is not a honeycomb structure, and its measured specific surface area is 283.8 m 2 / g. The gas chromatography test results for 6 cycles of reaction are shown in Table 9. It can be seen from Table 9 that, compared with Example 1, the maleic anhydride conversion rate of Comparative Example 5 decreases rapidly with the increase in the number of reaction cycles, indicating that the catalyst in Comparative Example 5 has poor stability; moreover, the selectivity of succinic anhydride in Comparative Example 5 is lower than that in Example 1.

[0081]

[0082] Comparative Example 6

[0083] In step (a), PEG6000 was replaced with PEG8000, and the other steps were the same as in Example 1. The SEM image of the obtained catalyst is shown in Figure 8 , from Figure 8 it can be seen that the obtained catalyst is not a honeycomb structure, and its specific surface area was measured to be 323.4 m 2 / g. The gas chromatography test results for 6 cycles of reaction are shown in Table 10. It can be seen from Table 10 that, compared with Example 1, the maleic anhydride conversion rate of Comparative Example 6 decreased rapidly with the increase in the number of reaction cycles, indicating that the catalyst of Comparative Example 6 has poor stability; moreover, the selectivity of succinic anhydride in Comparative Example 6 is lower than that in Example 1.

[0084]

Claims

1. A method for preparing succinic anhydride based on a honeycomb-type powdered nickel-molybdenum catalyst, characterized in that A honeycomb-type powdered nickel-molybdenum catalyst, maleic anhydride, solvent and hydrogen are mixed and then introduced into a tubular reactor (8) for hydrogenation reaction, followed by crystallization and separation to obtain succinic anhydride; The preparation method of the honeycomb type powdered nickel-molybdenum catalyst comprises the following steps: (a) nickel nitrate hexahydrate, ammonium molybdate, sodium silicate nonahydrate, urea and PEG6000 are mixed, and then deionized water is added for high-speed shearing to obtain a suspension containing a precipitate; (b) filtering the suspension containing the precipitate to obtain a precipitate; washing the precipitate to neutrality, adding deionized water to disperse it, spraying and granulating the obtained dispersion to obtain a catalyst precursor; calcining the catalyst precursor, reducing and passivating it in a hydrogen atmosphere to obtain a honeycomb type powdered nickel-molybdenum catalyst; In step (a), the mass ratio of nickel nitrate hexahydrate, ammonium molybdate, sodium silicate nonahydrate, urea, PEG6000 and deionized water is 1: 0.016-0.02: 0.5-0.8: 0.8-1.2: 0.02-0.04: 10-30.

2. The method for preparing succinic anhydride based on a honeycomb-type powder nickel-molybdenum catalyst according to claim 1, characterized in that In step (a), the high-speed shearing rate is 800-2000 rpm, the high-speed shearing temperature is 60-120° C., and the high-speed shearing time is 12-36 h.

3. The method for preparing succinic anhydride based on a honeycomb-type powdered nickel-molybdenum catalyst according to claim 1, characterized in that In step (b), the mass ratio of precipitate to deionized water is 1:10-12; the pressure of spray granulation is 0.15-0.3MPa, the temperature of spray granulation is 120-180°C; the roasting temperature is 450-650°C, the roasting time is 3-4h; the reduction temperature is 500-700°C, the reduction time is 3-4h; the passivation is carried out at room temperature for 3-4h using N2 containing 0.5-2wt.% O2.

4. The method for preparing succinic anhydride based on honeycomb-type powdered nickel-molybdenum catalyst according to claim 1, characterized in that The mass of the honeycomb type powdered nickel-molybdenum catalyst is 2-6% of the mass of maleic anhydride.

5. The method for preparing succinic anhydride based on honeycomb-type powdered nickel-molybdenum catalyst according to claim 1, characterized in that The solvent is acetic acid, and the mass ratio of the solvent to maleic anhydride is 2-8:

1.

6. The method for preparing succinic anhydride based on honeycomb-type powdered nickel-molybdenum catalyst according to claim 1, characterized in that The mass ratio of maleic anhydride to hydrogen is 1:800-1200.

7. The method for preparing succinic anhydride based on honeycomb-type powdered nickel-molybdenum catalyst according to claim 1, characterized in that The hydrogenation reaction temperature is 80-140°C, the hydrogenation reaction pressure is 0.5-3MPa, and the hydrogenation reaction time is 30-180min.

8. The method for preparing succinic anhydride based on honeycomb-type powdered nickel-molybdenum catalyst according to claim 1, characterized in that The crystallization temperature is 20-25°C and the crystallization time is 3-5min.

9. The method for preparing succinic anhydride based on honeycomb type powder nickel-molybdenum catalyst according to claim 1, characterized in that The device used in the method for preparing succinic anhydride based on honeycomb-type powdered nickel-molybdenum catalyst comprises a hydrogen cylinder (1), wherein the hydrogen cylinder (1), a premixing kettle (6), a hydraulic pump (7), a tubular reactor (8), a catalyst filter (9), a crystallization tank (10), a succinic anhydride filter (11) and a product succinic anhydride storage tank (12) are connected in sequence, the premixing kettle (6) is connected to a static mixer (5), the static mixer (5) is respectively connected to a solvent storage tank (2), a maleic anhydride storage tank (3) and a catalyst storage tank (4), the solvent storage tank (2) is connected to the succinic anhydride filter (11), and the catalyst storage tank (4) is connected to the catalyst filter (9).

Images