A catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, and its preparation method and application

Abstract

The present application relates to the field of catalyst technology, and specifically discloses a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, and its preparation method and application. The catalyst provided in the present application includes the following components: a ZrO2-modified α-Al2O3 carrier, V2O5, SnO2 and an auxiliary agent, wherein the mass fraction of ZrO2 in the ZrO2-modified α-Al2O3 carrier is 0.5-10%; the mass loading amount of the V2O5 in the carrier is 5-15%; the mass loading amount of the SnO2 in the carrier is 0.5-5%; the present application also provides a preparation method of the above-mentioned catalyst and its application in the process of synthesizing 2-cyanopyridine by ammoxidation of 2-alkylpyridine. The catalyst provided in the present application has the advantages of good selectivity and high yield, and can greatly reduce the production cost of synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine.

Description

Technical Field

[0001] The present application relates to the field of catalyst technology, and in particular to a catalyst for synthesizing 2-cyanopyridine through an ammoxidation reaction, and a preparation method and application thereof. Background Art

[0002] 2-Cyanopyridine can be used to prepare fine chemicals such as carboxylic acids, amides, and organic amines. It is an important organic synthesis intermediate and drug precursor and is widely used in pesticides, medicines, food, spices, and aquaculture. Currently, the ammoxidation of 2-methylpyridine to synthesize 2-cyanopyridine is an important route for preparing 2-cyanopyridine.

[0003] The catalysts used in the synthesis of 2-cyanopyridine by ammoxidation are mainly vanadium catalysts. For example, TiO 2 Load V 2 O 5 and MoO 3 The catalyst is used to catalyze the ammoxidation of 2-methylpyridine to synthesize 2-cyanopyridine. The yield of 2-cyanopyridine is 86%-91%, and the selectivity of 2-cyanopyridine is only 76% at most. There are also literature reports that a vanadium oxide is used as the main catalyst and other transition metal oxides and non-metal oxides are used as auxiliary agents to load on TiO 2 Although the catalyst can make the raw material conversion rate close to 100%, the mass yield of the target product is only 90.04% at most. Therefore, the catalyst currently used for the ammoxidation reaction to synthesize 2-cyanopyridine has one or more problems such as poor selectivity, low mass yield, and poor stability. Summary of the invention

[0004] In view of the problems of poor selectivity and low yield of the catalyst used in the existing ammoxidation reaction to synthesize 2-cyanopyridine, the present application provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, and a preparation method and application thereof.

[0005] In the first aspect, the present application provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, using the following technical solution:

[0006] A catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, comprising the following components: ZrO 2 Modified α-Al 2 O 3 Carrier, V 2 O 5 SnO 2 and additives,

[0007] The ZrO 2 Modified α-Al 2 O 3In the carrier, ZrO 2 The mass fraction is 0.5-10%;

[0008] The V 2 O 5 The mass loading in the carrier is 5-15%; the SnO 2 The mass loading in the carrier was 0.5-5%.

[0009] This application uses ZrO 2 Modified α-Al 2 O 3 As a carrier, V 2 O 5 and SnO 2 As an active component, an ammoxidation catalyst with high catalytic efficiency, good selectivity and excellent stability is prepared. The catalyst is used for the ammoxidation reaction of 2-methylpyridine to synthesize 2-cyanopyridine, and the selectivity of methylpyridine to synthesize 2-cyanopyridine reaches more than 82.0%, and the mass yield reaches more than 92.0%.

[0010] Optionally, the ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 The mass fraction is 1-5%.

[0011] Through experimental research, the present invention finds that further ZrO 2 Modified α-Al 2 O 3 ZrO in carrier 2 When the mass fraction of is controlled within the above range, the catalytic efficiency of the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction is higher, the selectivity of synthesizing 2-cyanopyridine by ammoxidation reaction reaches more than 83.0%, and the mass yield reaches more than 93.0%.

[0012] In some embodiments, the ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 The mass fraction of can be 0.5-1%, 0.5-3%, 0.5-5%, 0.5-8%, 0.5-10%, 1-3%, 1-5%, 1-8%, 1-10%, 3-5%, 3-8%, 3-10%, 5-8%, 5-10% or 8-10%.

[0013] In a specific embodiment, the ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2The mass fraction of can also be 0.5%, 1%, 3%, 5%, 8% or 10%.

[0014] Optionally, the SnO 2 The mass loading in the support was 1.3-3.8%.

[0015] In this application, SnO 2 The mass loading in the carrier will affect the performance of the catalyst. This application found through experimental research that the SnO 2 When the mass loading in the carrier is controlled within the above range, the obtained catalyst can achieve a selectivity of more than 84.0% and a mass yield of more than 94.0% for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0016] In some embodiments, the SnO 2 The mass loading in the support may be 0.5-1.3%, 0.5-2.6%, 0.5-3.8%, 0.5-5%, 1.3-2.6%, 1.3-3.8%, 1.3-5%, 2.6-3.8%, 2.6-5% or 3.8-5%.

[0017] In a specific embodiment, the SnO 2 The mass loading in the support may also be 0.5%, 1.3%, 2.6%, 3.8% or 5%.

[0018] Optionally, the auxiliary agent is selected from TiO 2 、MoO 3 , Sb 2 O 3 and P 2 O 5 One or more of .

[0019] In the present application, by adding an additive to the catalyst used for synthesizing 2-cyanopyridine by ammoxidation reaction, the catalytic performance of the catalyst can be improved, the stability of the catalyst can be increased, and the catalyst can be easily regenerated and used, thereby greatly reducing the production cost of synthesizing 2-cyanopyridine by ammoxidation reaction.

[0020] Optionally, the ZrO 2 Modified α-Al 2 O 3 The method for preparing a carrier comprises the following steps:

[0021] (1) Calcine pseudo-boehmite at 1000-1300°C for 3-6 hours to obtain α-Al 2 O 3 powder;

[0022] (2) ZrO 2, adhesive and α-Al 2 O 3 Mixing and extruding to obtain solid particles;

[0023] (3) Finally, the solid particles are calcined at 400-700°C for 5-7h to obtain ZrO 2 Modified α-Al 2 O 3 carrier.

[0024] The present application provides a ZrO 2 Modified α-Al 2 O 3 The method for preparing a carrier, wherein the carrier modified by the method above enables the prepared catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction to show higher activity and stability in the ammoxidation reaction.

[0025] Optionally, the binder is selected from one or more of sesbania powder, hydroxymethyl cellulose, high clay, aluminum sol and silica sol.

[0026] The catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction provided in the present application is regenerable, and after being deactivated by the reaction, its activity can be restored by calcination at 500-700°C.

[0027] In the present application, since the ammoxidation reaction catalyst will be deactivated after the ammoxidation reaction, carbon will be deposited inside the deactivated catalyst, and V 5+ The present invention reduces the deactivated catalyst to low-valent V by calcining it at 500-700°C, so that the carbon deposits inside the catalyst can be burned and decomposed, and the low-valent V can be reoxidized to V 5+ , the catalyst regains its activity and can be used to catalyze ammoxidation reactions.

[0028] In the present application, when the temperature of the regeneration calcination is too low and the time is too short, the carbon deposits in the deactivated ammoxidation catalyst cannot be completely burned; and when the temperature of the regeneration calcination is too high and the time is too long, the active components will agglomerate, resulting in a decrease in the performance of the ammoxidation catalyst. Therefore, the present application has found through experimental research that further controlling the temperature and time of the regeneration calcination within the above range can ensure that the ammoxidation catalyst fully recovers its activity and has excellent catalytic performance.

[0029] In a second aspect, the present application provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction and a preparation method thereof.

[0030] A method for preparing a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, comprising the following steps:

[0031] (1) Add V to an oxalic acid solution with a mass concentration of 5-20%2 O 5 or ammonium metavanadate, stir to dissolve; then add SnO 2 , add the additive after mixing evenly, stir evenly to obtain a mixed solution;

[0032] (2)Place ZrO 2 Modified α-Al 2 O 3 The carrier is impregnated in the mixed solution, then rotary evaporated at 60-90° C., dried at 90-150° C., and calcined at 400-700° C. for 3-6 hours to obtain a catalyst for preparing 3-cyanopyridine by ammoxidation.

[0033] Optionally, the impregnation is performed by multiple impregnations, and except for the different composition of the mixed solution and the calcination temperature, other operations and parameters are the same as (1) to (2) until the desired loading amount is reached.

[0034] In the present application, ammonium metavanadate is a precursor salt, which can be converted into V after calcination. 2 O 5 Therefore, in the preparation method of the ammoxidation catalyst, V can be added 2 O 5 Or ammonium metavanadate.

[0035] In a third aspect, the present application provides an application of a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction in a process for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine.

[0036] In a fourth aspect, the present application provides a process for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine, comprising the following steps: loading the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction into a reactor, continuously introducing 2-methylpyridine, ammonia and oxygen, and reacting at 350-390°C.

[0037] In this application, the size of the reactor is 25 mm in inner diameter, 1200 mm in length, the catalyst loading is 0.05-0.1 L, and the space velocity is 400-2000 h -1 , the reaction temperature is 350-390℃.

[0038] In summary, this application has the following beneficial effects:

[0039] 1. This application uses ZrO 2 Modified α-Al 2 O 3 As a carrier, V 2 O 5 and SnO 2As an active component, a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction is prepared. The ammoxidation reaction catalyst is used to catalyze 2-methylpyridine to synthesize 2-cyanopyridine, which can achieve a selectivity of more than 82.0% and a mass yield of more than 92.0%.

[0040] 2. This application further converts ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 The mass fraction of is controlled between 1-5%, and the obtained catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction has better selectivity and better catalytic effect, and can make the selectivity of synthesizing 2-cyanopyridine by ammoxidation reaction reach more than 83.0%, and the mass yield reach more than 93.0%.

[0041] 3. This application further adds SnO 2 The mass loading in the carrier is controlled within the range of 1.3-3.8%, and the obtained catalyst can make the selectivity of synthesizing 2-cyanopyridine by ammoxidation reaction reach more than 84.0%, and the mass yield reaches more than 94.0%.

[0042] 4. The ammonia oxidation reaction catalyst provided in the present application is regenerable. The deactivated ammonia oxidation reaction catalyst can recover its activity after calcination at 500-700°C, and still has excellent catalytic effect after regeneration. DETAILED DESCRIPTION

[0043] In a first aspect, the present application provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, comprising the following components: ZrO 2 Modified α-Al 2 O 3 Carrier, V 2 O 5 SnO 2 and additives, the ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 The mass fraction of V 2 O 5 The mass loading in the carrier is 5-15%; the SnO 2 The mass loading amount in the carrier is 0.5-5%. 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 The mass fraction of SnO is 1-5%. 2The mass loading in the carrier is 1.5-3.5%. The auxiliary agent is selected from TiO 2 、MoO 3 , Sb 2 O 3 and P 2 O 5 One or more of .

[0044] The above ZrO 2 Modified α-Al 2 O 3 The method for preparing a carrier comprises the following steps:

[0045] (1) Calcine pseudo-boehmite at 1000-1300°C for 3-6 hours to obtain α-Al 2 O 3 powder;

[0046] (2) ZrO 2 , adhesive and α-Al 2 O 3 Mixing and extruding to obtain solid particles;

[0047] (3) Finally, the solid particles are calcined at 400-700°C for 5-7h to obtain ZrO 2 Modified α-Al 2 O 3 carrier.

[0048] In a second aspect, the present application provides a method for preparing a catalyst for synthesizing 2-cyanopyridine by an ammoxidation reaction, comprising the following steps:

[0049] (1) Add V to an oxalic acid solution with a mass concentration of 5-20% 2 O 5 or ammonium metavanadate, stir to dissolve; then add SnO 2 , add the additive after mixing evenly, stir evenly to obtain a mixed solution;

[0050] (2)Place ZrO 2 Modified α-Al 2 O 3 The carrier is impregnated in the mixed solution, then rotary evaporated at 60-90° C., dried at 90-150° C., and calcined at 400-700° C. for 3-6 hours to obtain a catalyst for preparing 3-cyanopyridine by ammoxidation.

[0051] In the above step (2), the impregnation can be carried out multiple times. Except for the different composition of the mixed solution and the calcination temperature, other operations and parameters are the same as (1) to (2) until the desired loading amount is reached.

[0052] In a third aspect, the present application provides a method for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine, comprising the following steps: loading the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction in a stainless steel fixed bed reactor having an inner diameter of 25 mm and a length of 1200 mm, then introducing 2-methylpyridine, ammonia and oxygen, and reacting at 350-390°C; wherein the catalyst loading amount is 0.05-0.1L, and the air velocity is 400-2000m / s. 3 / h; converted according to air (the oxygen content in air is 20%), 2-methylpyridine: ammonia: oxygen = 1: (1.2-5): (6-20).

[0053] In this application, the purity of pseudo-boehmite is ≥99.95%, purchased from Yangzhou Zhongtianli New Materials Co., Ltd.; ZrO 2 The powder was purchased from a commercial source with a purity of ≥99%; V 2 O 5 and SnO 2 The powder was purchased from commercial sources with a purity of ≥99%; ammonium metavanadate was purchased from commercial sources with a purity of ≥99%; sesbania powder was purchased from Beijing Haifuda Technology Co., Ltd.; the remaining raw materials, reagents, solvents, etc. can all be purchased from commercial sources.

[0054] The present application is further described in detail below in combination with preparation examples, embodiments and performance testing experiments.

[0055] Preparation Example 1-6

[0056] Preparation Examples 1-6 provide a ZrO 2 Modified α-Al 2 O 3 carrier.

[0057] The difference between the above preparation examples is that: ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 The specific quality scores are shown in Table 1 below.

[0058] Preparation Example 1-6 provides ZrO 2 Modified α-Al 2 O 3 The method for preparing a carrier comprises the following steps:

[0059] (1) Pseudo-boehmite was calcined at 1100°C for 4 h to obtain α-Al 2 O 3 powder;

[0060] (2) ZrO 2 Powder, Sesbania powder and α-Al 2 O 3The powders are mixed and extruded to obtain solid particles with a particle size of 3-8 mm;

[0061] (3) Finally, the solid particles were calcined at 500 °C for 6 h to obtain ZrO 2 Modified α-Al 2 O 3 carrier.

[0062] Table 1 ZrO provided by Preparation Examples 1-6 2 Modified α-Al 2 O 3 The amount of each component added to the carrier

[0063]

[0064] Comparative Preparation Example 1

[0065] Comparative Preparation Example 1 provides a ZrO 2 Modified α-Al 2 O 3 carrier.

[0066] The difference between the comparative preparation example and the preparation example 3 is that: ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 The mass fraction is 12%.

[0067] In the preparation method of comparative preparation example 1, ZrO 2 The amount of powder added was 12g, the amount of sesbania powder added was 10g, and the amount of α-Al 2 O 3 Powder 78g.

[0068] Examples 1-6

[0069] Examples 1-6 respectively provide a catalyst for synthesizing 2-cyanopyridine through an ammoxidation reaction.

[0070] The difference between the above embodiments is that the carriers in the catalyst used for the ammoxidation reaction to synthesize 2-cyanopyridine are derived from Preparation Examples 1-6 respectively.

[0071] The preparation method of the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction provided in Example 1-10 comprises the following steps:

[0072] (1) Dissolve 11.2 g of oxalic acid in 50 g of water at 60 °C, then add 7.0 g of ammonium metavanadate and add 1.9 g of SnO 2 dissolve, then add 0.67g TiO 2 , stir and mix for 30 min to obtain a mixed solution.

[0073] (2) 50 g ZrO 2 Modified α-Al 2 O 3 The carrier is impregnated in the mixed solution, and then subjected to rotary evaporation at 90° C., dried at 125° C. for 12 h, and calcined at 600° C. for 3 h to obtain a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0074] Examples 7-10

[0075] Examples 7-10 respectively provide a catalyst for synthesizing 2-cyanopyridine through an ammoxidation reaction.

[0076] The difference between the above embodiment and embodiment 3 is that: SnO 2 The specific mass loading in the carrier is shown in Table 2 below.

[0077] Table 2 SnO in the catalysts provided in Examples 3 and 7-10 2 Mass loading in the carrier

[0078]

[0079] Embodiment 11

[0080] Example 11 provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0081] The preparation method of the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction is as follows: the deactivated catalyst of Example 9 is calcined at 600° C. for 4 h to obtain a regenerated catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0082] Comparative Example 1

[0083] Comparative Example 1 provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0084] The difference between the above embodiment and embodiment 3 is that the carrier in the catalyst used for synthesizing 2-cyanopyridine by ammoxidation reaction comes from comparative preparation example 1.

[0085] Comparative Example 2

[0086] Comparative Example 2 provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0087] The difference between the above embodiment and embodiment 3 is that: ZrO 2 Modified α-Al 2 O 3 The support was replaced by α-Al 2 O 3 .

[0088] The above α-Al 2 O 3 The preparation method is:

[0089] (1) Pseudo-boehmite was calcined at 1200°C for 4 h to obtain α-Al 2 O 3 powder;

[0090] (2) Then 10 g of sesbania powder and α-Al 2 O 3 87g of the powder was mixed and extruded to obtain solid particles with a particle size of 3-8mm; (3) the solid particles were calcined at 500°C for 6h to obtain α-Al 2 O 3 .

[0091] Comparative Example 3

[0092] Comparative Example 3 provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0093] The difference between the above embodiment and embodiment 3 is that: ZrO 2 Modified α-Al 2 O 3 The carrier was replaced by SiO 2 Modified α-Al 2 O 3 carrier.

[0094] The above SiO 2 Modified α-Al 2 O 3 The preparation method of the carrier is:

[0095] (1) Pseudo-boehmite was calcined at 1100°C for 4 h to obtain α-Al 2 O 3 powder;

[0096] (2) Then 3g SiO 2 powder, 10g sesbania powder and 87g α-Al 2 O 3 The powders are mixed and extruded to obtain solid particles with a particle size of 3-8 mm;

[0097] (3) Finally, the solid particles were calcined at 500 °C for 6 h to obtain SiO 2 Modified α-Al 2 O 3 carrier.

[0098] Comparative Example 4

[0099] Comparative Example 4 provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0100] The difference between the above embodiment and embodiment 3 is that: in the catalyst used for the ammoxidation reaction to synthesize 2-cyanopyridine, SnO 2 The mass loading in the carrier is 0.

[0101] Comparative Example 5

[0102] Comparative Example 5 provides a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction.

[0103] The difference between the above embodiment and embodiment 3 is that: in the catalyst used for the ammoxidation reaction to synthesize 2-cyanopyridine, SnO 2 The mass loading in the support was 6%.

[0104] Application Example 1-11

[0105] Application Examples 1-11 respectively provide a process for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine.

[0106] The difference between the above application examples is that in the process of synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine, the catalysts used for synthesizing 2-cyanopyridine by ammoxidation reaction are derived from Examples 1-11 respectively.

[0107] The above-mentioned process for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine comprises the following steps: loading a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction in a fixed bed reactor made of stainless steel with an inner diameter of 25 mm and a length of 1200 mm, and then continuously introducing 2-methylpyridine, ammonia and oxygen into the reactor to react at 370° C. to prepare 2-cyanopyridine. The loading amount of the catalyst is 0.05 L, and the air velocity is 1000 m / s. 3 / h, 3-methylpyridine: ammonia: oxygen (converted to air) = 1:2:10 Comparative Application Example 1-5

[0108] Comparative Application Examples 1-5 respectively provide a process for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine.

[0109] The difference between the above comparative application example and application example 3 is that in the process of synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine, the catalysts used for synthesizing 2-cyanopyridine by ammoxidation reaction are derived from comparative examples 1-5 respectively.

[0110] Performance testing

[0111] According to the method of Application Example 1-11 and Comparative Application Example 1-5, 2-cyanopyridine was synthesized, and the reaction was run continuously for 1 week. The selectivity and mass yield of 2-cyanopyridine were recorded, and the effect of each catalyst was evaluated based on the conversion rate and mass yield. The results are shown in Table 3 below.

[0112] The calculation formula of 2-cyanopyridine selectivity and mass yield is as follows:

[0113] Selectivity = {mass fraction of 2-cyanopyridine in the discharge × discharge amount / 104.11} / (2-methylpyridine feed amount - discharge amount × mass fraction of 2-methylpyridine in the discharge) / 93.127} × 100%

[0114] Mass yield = (discharge amount × mass fraction of 2-cyanopyridine in the discharge / 2-methylpyridine feed amount) × 100%

[0115] Table 3 Results of the test on the use of the catalysts provided in Examples 1-11 and Comparative Examples 1-5

[0116]

[0117]

[0118] According to the test results of Table 3, the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction catalyzed by 2-picoline to synthesize 2-cyanopyridine, the selectivity of 2-cyanopyridine can reach more than 82%, and the mass yield reaches more than 92%. While the catalyst prepared by comparative example 1-5 catalyzed 2-picoline to synthesize 2-cyanopyridine, the selectivity of 2-cyanopyridine was only 73.8-80.3%, and the mass yield was 86.5-91.3%. Therefore, it is explained that the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction provided by the present application has good selectivity and catalytic efficiency, and it is used in the production process of synthesizing 2-cyanopyridine by ammoxidation, which can save raw materials and greatly reduce the production cost of 2-cyanopyridine.

[0119] The test results of application examples 1-6 show that as ZrO 2 Modified α-Al 2 O 3 In the carrier, ZrO 2 With the increase of the mass fraction of ZrO, the selectivity and mass yield of the obtained catalyst showed a trend of first increasing and then decreasing. Further comparison found that the selectivity of 2-cyanopyridine in Application Examples 2-4 was 83.6-84.2% (≥83%), and the mass yield was 93.6-94.7% (≥93%); while the selectivity of Application Examples 1 and Application Examples 5-6 was 82.1-82.7%, and the yield was 92.3-93.2%. Therefore, it is shown that the present application further adds ZrO 2Modified α-Al 2 O 3 In the carrier, ZrO 2 The mass fraction of is controlled between 1-5%, and the obtained catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction has better selectivity and better catalytic effect, and can make the selectivity of synthesizing 2-cyanopyridine by ammoxidation reaction reach more than 83.0%, and the mass yield reach more than 93.0%.

[0120] The test results of Application Examples 3 and 10 show that as the active component SnO in the catalyst 2 With the increase of mass fraction, the selectivity of the prepared catalyst shows a trend of first increasing and then decreasing, and the mass yield shows a trend of first increasing and then remaining basically unchanged. Further comparison shows that the selectivity of 2-cyanopyridine in Application Examples 3 and Application Examples 8-9 is 84.2-85.1% (≥84%), and the mass yield is 94.0-94.4% (≥94%); while the selectivity of 2-cyanopyridine in Application Example 7 is only 83.4%, and the selectivity of 2-cyanopyridine in Application Example 10 is only 83.8%. Therefore, it is shown that the present application further increases SnO 2 The mass loading in the carrier is controlled within the range of 1.3-3.8%, and the obtained catalyst can make the selectivity of synthesizing 2-cyanopyridine by ammoxidation reaction reach more than 84.0%, and the mass yield reaches more than 94.0%.

[0121] From the test results of Application Examples 9 and 11, it can be seen that in Application Example 11, the catalyst deactivated and regenerated in Application Example 9 was used to re-carry out the ammoxidation catalytic reaction, and the selectivity and mass yield of 2-cyanopyridine decreased slightly, but the selectivity was still above 84%, and the mass yield was still above 93%, which fully met the use requirements.

[0122] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction, characterized in that: The invention comprises the following components: ZrO2 modified α-Al2O3 carrier, V2O5, SnO2 and additives. In the ZrO2-modified α-Al2O3 carrier, the mass fraction of ZrO2 is 0.5-10%; The mass loading amount of the V2O5 in the carrier is 5-15%; the mass loading amount of the SnO2 in the carrier is 0.5-5%.

2. The catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction according to claim 1, characterized in that: In the ZrO2-modified α-Al2O3 carrier, the mass fraction of ZrO2 is 1-5%.

3. The catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction according to claim 1, characterized in that: The mass loading amount of SnO2 in the carrier is 1.5-3.5%.

4. The catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction according to claim 1, characterized in that: The auxiliary agent is selected from one or more of TiO2, MoO3, Sb2O3 and P2O5.

5. The catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction according to any one of claims 1 to 4, characterized in that: The preparation method of the ZrO2-modified α-Al2O3 carrier comprises the following steps: (1) calcining pseudo-boehmite at 1000-1300°C for 3-6 hours to obtain α-Al2O3 powder; (2) ZrO2, a binder and α-Al2O3 are mixed and extruded to obtain solid particles; (3) Finally, the solid particles are calcined at 400-700 °C for 5-7 h to obtain a ZrO2-modified α-Al2O3 carrier.

6. The catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction according to claim 5, characterized in that: The binder is selected from one or more of sesbania powder, hydroxymethyl cellulose, high clay, aluminum sol and silica sol.

7. A method for preparing a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Add V2O5 or ammonium metavanadate to an oxalic acid solution with a mass concentration of 5-20%, and stir to dissolve; then add SnO2, mix well, add an additive, and stir well to obtain a mixed solution; (2) impregnating a ZrO2-modified α-Al2O3 carrier in the mixed solution, then subjecting the mixture to rotary evaporation at 60-90°C, drying at 90-150°C, and calcining at 400-700°C for 3-6 h to obtain a catalyst for preparing 3-cyanopyridine by ammoxidation.

8. The method for preparing a catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction according to claim 7, characterized in that: The impregnation is performed multiple times. Except for the different composition of the mixed solution and the calcination temperature, other operations and parameters are the same as (1) to (2) until the desired loading amount is reached.

9. Use of the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction as claimed in any one of claims 1 to 6 in a process for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine.

10. A process for synthesizing 2-cyanopyridine by ammoxidation of 2-methylpyridine, characterized in that: The method comprises the following steps: loading the catalyst for synthesizing 2-cyanopyridine by ammoxidation reaction according to any one of claims 1 to 6 into a reactor, continuously introducing 2-methylpyridine, ammonia and oxygen, and reacting at 350-390° C.

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