Preparation method of manganese dioxide supported catalyst as well as product and application thereof

Abstract

The invention relates to the technical field of catalyst synthesis, in particular to a preparation method of a manganese dioxide supported catalyst and a product and application thereof, and the preparation method at least comprises the following steps: grinding and sieving a molecular sieve, soaking in a buffer solution, and carrying out ultrasonic treatment to obtain a mixed solution; filtering the mixed solution to obtain a filter cake, and drying the filter cake to obtain molecular sieve powder; and uniformly mixing manganese dioxide and the molecular sieve powder according to a mass ratio of 1: (3-7), and sequentially calcining, grinding and sieving to obtain the manganese dioxide supported catalyst. By controlling the mass ratio of the manganese dioxide to the molecular sieve powder and simultaneously controlling process parameters such as calcination conditions and the like, the prepared manganese dioxide supported catalyst has the advantages of high cycling stability, high reaction rate and yield of diisopropylamine acrolein synthesized by using the manganese dioxide supported catalyst, simple process, no need of complex equipment, controllable cost and wide application prospect. Good industrial application prospects are realized.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst synthesis, and in particular to a preparation method of a manganese dioxide supported catalyst, a product thereof and an application thereof. Background Art

[0002] Diisopropylaminoacrolein is an important intermediate in the synthesis of 2-chloronicotinic acid. In pesticides, 2-chloronicotinic acid is primarily used to synthesize the herbicides nicosulfuron and diflufenac, and the fungicide boscalid. These are new, highly effective, environmentally friendly pesticides that have become dominant in both domestic and international markets. In medicine, 2-chloronicotinic acid is primarily used to synthesize the anti-AIDS drug nevirapine, the antidepressant mirtazapine, and the non-steroidal anti-inflammatory analgesics niflumic acid and nicotinamide.

[0003] At present, the synthesis of diisopropylamino acrolein usually requires a catalyst such as manganese dioxide to improve efficiency and yield. For example, Chinese invention patent application CN104876861A mixes propargyl alcohol and diisopropylamine in a molar ratio of 1:1 and dissolves them in toluene. Manganese dioxide is added as a catalyst, and air or oxygen is introduced. The reaction is carried out at 30-110 ° C and 0.5-2 MPa for 8-20 hours. After the reaction is completed, the catalyst manganese dioxide is filtered to remove the manganese dioxide, and the filtrate is subjected to desolventizing treatment to obtain diisopropylamino acrolein. However, when the filtered catalyst is recovered and applied, this synthesis method has problems such as low application times and low yield.

[0004] In this context, developing a catalyst that can improve the yield of diisopropylaminoacrolein is of great significance for the industrial production of 2-chloronicotinic acid. Summary of the Invention

[0005] In order to solve the problems in the prior art, the first aspect of the present invention provides a method for preparing a manganese dioxide supported catalyst, comprising at least the following steps:

[0006] The molecular sieve is ground and sieved, and then immersed in a buffer solution for ultrasonic treatment to obtain a mixed solution;

[0007] Filtering the mixed solution to obtain a filter cake, and drying the filter cake to obtain molecular sieve powder;

[0008] Manganese dioxide and the molecular sieve powder are uniformly mixed in a mass ratio of 1:(3-7), and then calcined, ground, and sieved in sequence to obtain a manganese dioxide supported catalyst.

[0009] In one embodiment, the molecular sieve includes any one of 3A molecular sieve, 4A molecular sieve, 5A molecular sieve, and 13X molecular sieve.

[0010] In one embodiment, the ultrasonic power during the ultrasonic treatment is 180w.

[0011] In one embodiment, the mass ratio of manganese dioxide to molecular sieve is 1:(3-5), which can be 1:3, 1:4, or 1:5.

[0012] In one embodiment, the mesh size of the grinding and sieving is 100-200 mesh.

[0013] In one embodiment, the mesh size of the ground and sieved material is 100-150 mesh, which can be 100 mesh, 110 mesh, 120 mesh, 130 mesh, 140 mesh, or 150 mesh.

[0014] In one embodiment, the buffer solution is an ammonia-ammonium chloride buffer solution with a pH value of 9-10.

[0015] In one embodiment, the ammonia-ammonium chloride buffer solution is prepared by dissolving ammonium chloride in distilled water, stirring continuously in an ice-water bath, adding ammonia, and finally diluting the volume to 500 mL with distilled water.

[0016] In one embodiment, the ultrasonic treatment time is 1-3 hours, which can be 1 hour, 2 hours, or 3 hours.

[0017] In one embodiment, the filter cake is rinsed with deionized water to neutrality before drying.

[0018] In one embodiment, the drying condition is drying at 100-200° C. for 3-10 h.

[0019] In one embodiment, the drying condition is drying at 150-200° C. for 5-10 h.

[0020] In one embodiment, the calcination temperature is 550-560°C.

[0021] In one embodiment, the calcination time is 10-20 minutes.

[0022] In one embodiment, the mesh size of the sieve is 100-150 meshes.

[0023] In one embodiment, the calcining, grinding, and sieving steps are repeated three times.

[0024] The second aspect of the present invention provides a manganese dioxide supported catalyst prepared according to the above preparation method.

[0025] A third aspect of the present invention provides an application of a manganese dioxide-supported catalyst, wherein the manganese dioxide-supported catalyst is applied to prepare diisopropylaminoacrolein.

[0026] In one embodiment, the preparation method of diisopropylamino acrolein comprises: sequentially adding diisopropylamine, propargyl alcohol, a manganese dioxide-supported catalyst, and toluene into a high-pressure reactor, closing the reactor, turning on stirring, heating to 80° C., introducing oxygen, maintaining the internal pressure of the reactor at 0.1-0.2 MPa, and keeping warm for 3-4 hours. After detecting that the propargyl alcohol content is less than 0.01%, filtering the reaction solution, and the filtrate is diisopropylamino acrolein.

[0027] Beneficial effects

[0028] 1. By controlling the mass ratio of manganese dioxide to molecular sieve powder to 1:(3-7), the catalyst prepared in the present invention has excellent structural stability, ensuring that it retains good catalytic activity after multiple cycles. Experimental results show that the yield of diisopropylaminoacrolein remains above 90% after 15 cycles of the catalyst prepared in this manner. This may be due to the fact that when the mass ratio is 1:(3-7), MnO2 forms Mn-O-Si bonds with Si-OH groups on the molecular sieve surface, while molten MnO2 simultaneously penetrates the interstitial spaces of the molecular sieve, forming a "mosaic" structure. This dual effect prevents the MnO2 from falling off during recycling, improving structural stability.

[0029] 2. The present invention ensures the precise dispersion of molten MnO2 by controlling the calcination conditions: 550-560°C, 10-20 min, and at the same time forms a stable Mn-O-Si bond with MnO2, thereby avoiding the destruction of the carrier crystal form and the phase change of the active component, and further improving the cyclic stability of the catalyst.

[0030] 3. The present invention controls the mesh size and limits the pH value of the buffer solution to 9-10. On the one hand, it is beneficial to balance the particle size and specific surface area to ensure the uniform distribution of manganese dioxide. On the other hand, it can promote the adsorption of manganese dioxide on the surface of the molecular sieve, enhance the bonding strength between manganese dioxide and the carrier, and thus improve the cyclic stability of the catalyst.

[0031] 4. The preparation method provided by the present invention has a simple process, does not require complex equipment, and has controllable costs. In the process of synthesizing diisopropylaminoacrolein using the manganese dioxide-supported catalyst prepared by the present invention, it has the characteristics of high catalytic activity, high reaction rate and yield, and catalyst recycling, and has good industrial application prospects. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The experimental methods for which specific conditions are not specified in the examples are carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used for which the manufacturer is not specified are all conventional products that can be purchased commercially.

[0033] Example 1

[0034] A first aspect of this embodiment provides a method for preparing a manganese dioxide supported catalyst, comprising the following steps:

[0035] The molecular sieve was ground through a 100-mesh sieve and then immersed in a pH = 9 ammonia-ammonium chloride buffer solution and ultrasonically treated for 2 h to obtain a mixed solution;

[0036] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 150° C. for 5 h to obtain a molecular sieve powder;

[0037] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:3, and then calcined, ground, and passed through a 100-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0038] The molecular sieve is 3A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0039] The calcination conditions are as follows: heating to 550° C. at a programmed heating rate of 150° C. / h, maintaining for 10 minutes, and then cooling naturally.

[0040] The calcining, grinding and sieving steps were repeated three times.

[0041] In a second aspect, this embodiment provides a manganese dioxide supported catalyst prepared according to the above preparation method.

[0042] A third aspect of this embodiment provides an application of a manganese dioxide-supported catalyst, wherein the manganese dioxide-supported catalyst is used to prepare diisopropylaminoacrolein.

[0043] The preparation method of diisopropylaminoacrolein comprises the following steps: sequentially adding 51 g of diisopropylamine, 28 g of propargyl alcohol, 5 g of a manganese dioxide-supported catalyst, and 200 mL of toluene to an autoclave, closing the autoclave, turning on stirring, heating the autoclave to 80°C, introducing oxygen, maintaining the internal pressure of the autoclave at 0.15 MPa, and incubating for 3 hours. After testing to determine if the propargyl alcohol content is less than 0.01%, the reaction mixture is filtered, and the filtrate is diisopropylaminoacrolein. The filter cake is the recovered manganese dioxide-supported catalyst, which can be used to prepare the next batch of diisopropylaminoacrolein.

[0044] Example 2

[0045] A first aspect of this embodiment provides a method for preparing a manganese dioxide supported catalyst, comprising the following steps:

[0046] The molecular sieve was ground through a 150-mesh sieve and then immersed in a pH = 10 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0047] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0048] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:5, and then calcined, ground, and passed through a 150-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0049] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0050] The calcination conditions are as follows: heating to 560° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 20 minutes, and then cooling naturally.

[0051] The calcining, grinding and sieving steps were repeated three times.

[0052] In a second aspect, this embodiment provides a manganese dioxide supported catalyst prepared according to the above preparation method.

[0053] A third aspect of this embodiment provides an application of a manganese dioxide-supported catalyst, wherein the manganese dioxide-supported catalyst is used to prepare diisopropylaminoacrolein.

[0054] The preparation method of diisopropylaminoacrolein comprises the following steps: sequentially adding 51 g of diisopropylamine, 28 g of propargyl alcohol, 7.5 g of a manganese dioxide-supported catalyst, and 200 mL of toluene to an autoclave, closing the autoclave, turning on stirring, heating the autoclave to 80°C, introducing oxygen, maintaining the internal pressure of the autoclave at 0.15 MPa, and incubating for 3 hours. After testing to determine if the propargyl alcohol content is less than 0.01%, the reaction mixture is filtered, and the filtrate is diisopropylaminoacrolein. The filter cake is the recovered manganese dioxide-supported catalyst, which can be used to prepare the next batch of diisopropylaminoacrolein.

[0055] Comparative Example 1

[0056] The specific implementation of this comparative example is the same as that of Example 2, except that the preparation method of the manganese dioxide supported catalyst comprises the following steps:

[0057] The molecular sieve was ground through a 150-mesh sieve and then immersed in a pH = 10 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0058] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0059] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:5, and then calcined, ground, and passed through a 150-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0060] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0061] The calcination conditions are as follows: heating to 580° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 20 minutes, and then cooling naturally.

[0062] The calcining, grinding and sieving steps were repeated three times.

[0063] Comparative Example 2

[0064] The specific implementation of this comparative example is the same as that of Example 2, except that the preparation method of the manganese dioxide supported catalyst comprises the following steps:

[0065] The molecular sieve was ground through a 150-mesh sieve and then immersed in a pH = 10 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0066] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0067] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:5, and then calcined, ground, and passed through a 150-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0068] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0069] The calcination conditions are as follows: heating to 560° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 30 minutes, and then cooling naturally.

[0070] The calcining, grinding and sieving steps were repeated three times.

[0071] Comparative Example 3

[0072] The specific implementation of this comparative example is the same as that of Example 2, except that the preparation method of the manganese dioxide supported catalyst comprises the following steps:

[0073] The molecular sieve was ground through a 50-mesh sieve and then immersed in a pH = 10 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0074] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0075] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:5, and then calcined, ground, and passed through a 50-mesh sieve in sequence to obtain a manganese dioxide supported catalyst.

[0076] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0077] The calcination conditions are as follows: heating to 560° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 20 minutes, and then cooling naturally.

[0078] The calcining, grinding and sieving steps were repeated three times.

[0079] Comparative Example 4

[0080] The specific implementation of this comparative example is the same as that of Example 2, except that the preparation method of the manganese dioxide supported catalyst comprises the following steps:

[0081] The molecular sieve was ground through a 250 mesh sieve and then immersed in a pH = 10 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0082] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0083] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:5, and then calcined, ground, and passed through a 250-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0084] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0085] The calcination conditions are as follows: heating to 560° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 20 minutes, and then cooling naturally.

[0086] The calcining, grinding and sieving steps were repeated three times.

[0087] Comparative Example 5

[0088] The specific implementation of this comparative example is the same as that of Example 2, except that the preparation method of the manganese dioxide supported catalyst comprises the following steps:

[0089] The molecular sieve was ground through a 150-mesh sieve and then immersed in a pH=8 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0090] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0091] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:5, and then calcined, ground, and passed through a 150-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0092] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0093] The calcination conditions are as follows: heating to 560° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 20 minutes, and then cooling naturally.

[0094] The calcining, grinding and sieving steps were repeated three times.

[0095] Comparative Example 6

[0096] The specific implementation of this comparative example is the same as that of Example 2, except that the preparation method of the manganese dioxide supported catalyst comprises the following steps:

[0097] The molecular sieve was ground through a 150-mesh sieve and then immersed in a pH = 10 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0098] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0099] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:7.5, and then calcined, ground, and passed through a 150-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0100] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0101] The calcination conditions are as follows: heating to 560° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 20 minutes, and then cooling naturally.

[0102] The calcining, grinding and sieving steps were repeated three times.

[0103] Comparative Example 7

[0104] The specific implementation of this comparative example is the same as that of Example 2, except that the preparation method of the manganese dioxide supported catalyst comprises the following steps:

[0105] The molecular sieve was ground through a 150-mesh sieve and then immersed in a pH = 10 ammonia-ammonium chloride buffer solution and ultrasonically treated for 3 h to obtain a mixed solution;

[0106] The mixed solution was filtered to obtain a filter cake, the filter cake was rinsed with deionized water until neutral, and dried in an oven at 200° C. for 8 h to obtain a molecular sieve powder;

[0107] Manganese dioxide and the molecular sieve powder were uniformly mixed in a mass ratio of 1:2, and then calcined, ground, and passed through a 150-mesh sieve to obtain a manganese dioxide-supported catalyst.

[0108] The molecular sieve is 4A molecular sieve. The ultrasonic power during the ultrasonic treatment is 180W.

[0109] The calcination conditions are as follows: heating to 560° C. at a programmed heating rate of 150° C. / h, maintaining the temperature for 20 minutes, and then cooling naturally.

[0110] The calcining, grinding and sieving steps were repeated three times.

[0111] Comparative Example 8

[0112] This comparative example provides a method for preparing diisopropylaminoacrolein. The method comprises sequentially adding 51 g of diisopropylamine, 28 g of propargyl alcohol, 7.5 g of manganese dioxide, and 200 mL of toluene to an autoclave. The autoclave is closed, stirred, and heated to 80°C. Oxygen is then introduced, and the reactor pressure is maintained at 0.15 MPa. The reaction mixture is incubated for 8 hours. The propargyl alcohol content is determined to be less than 0.01%. The reaction mixture is filtered, and the filtrate is diisopropylaminoacrolein. The filter cake is the recovered manganese dioxide catalyst, which can be used to prepare the next batch of diisopropylaminoacrolein.

[0113] Performance Testing

[0114] Cyclic stability test:

[0115] The catalyst sets prepared in each example and comparative example were used to prepare diisopropylaminoacrolein, and the reaction time and yield of diisopropylaminoacrolein were observed at different application times. The test results are shown in Tables 1-3.

[0116] Table 1

[0117]

[0118] Table 2

[0119]

[0120]

[0121] Table 3

[0122]

[0123] As can be seen from Tables 1-3, the manganese dioxide-supported catalyst prepared in this application maintained excellent catalytic activity, stable reaction rate, and essentially unchanged yield after 15 cycles. In contrast, when conventional manganese dioxide was used as the catalyst (Comparative Example 8), the reaction rate was slow, and after five cycles, the reaction time was prolonged, and the yield decreased to 65.8%.

Claims

1. A method for preparing a manganese dioxide supported catalyst, characterized in that: At least the following steps are included: The molecular sieve is ground and sieved, and then immersed in a buffer solution for ultrasonic treatment to obtain a mixed solution; Filtering the mixed solution to obtain a filter cake, and drying the filter cake to obtain molecular sieve powder; Manganese dioxide and the molecular sieve powder are uniformly mixed in a mass ratio of 1:(3-7), and then calcined, ground, and sieved in sequence to obtain a manganese dioxide supported catalyst.

2. The method for preparing a manganese dioxide supported catalyst according to claim 1, wherein The mass ratio of the manganese dioxide to the molecular sieve is 1:(3-5).

3. The method for preparing a manganese dioxide supported catalyst according to claim 1, wherein The mesh number of the grinding and sieving is 100-200 meshes.

4. The method for preparing a manganese dioxide supported catalyst according to claim 3, wherein The mesh number of the grinding and sieving is 100-150 meshes.

5. The method for preparing a manganese dioxide supported catalyst according to claim 1, wherein The buffer solution is an ammonia-ammonium chloride buffer solution with a pH value of 9-10.

6. The method for preparing a manganese dioxide supported catalyst according to claim 1, wherein The calcination temperature is 550-560°C.

7. The method for preparing a manganese dioxide supported catalyst according to claim 5, wherein The calcination time is 10-20 minutes.

8. The method for preparing a manganese dioxide supported catalyst according to claim 1, wherein The molecular sieve includes any one of 3A molecular sieve, 4A molecular sieve, 5A molecular sieve and 13X molecular sieve.

9. A manganese dioxide supported catalyst, characterized in that Prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the manganese dioxide supported catalyst according to claim 9, characterized in that: The manganese dioxide supported catalyst is used for preparing diisopropylaminoacrolein.

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