Preparation method and application of 5-norbornene-2-aldehyde

Abstract

The invention relates to the technical field of organic synthesis, and discloses a preparation method and application of 5-norbornene-2-aldehyde. The method comprises the following steps: mixing cyclopentadiene and acrolein, and carrying out a first-stage reaction and a second-stage reaction, wherein the temperature of the second-stage reaction is 5-15% higher than that of the first-stage reaction; wherein when the content of acrolein is less than 25 vol% and the content of cyclopentadiene is less than 35 vol% through GC analysis, the temperature is raised to enter the second-stage reaction. The preparation method provided by the invention can improve the conversion rate and reaction rate of the raw materials and the yield of the target product, and can also improve the stability and safety of the synthesis process.

Description

Technical Field

[0001] The present invention relates to the technical field of organic synthesis, and particularly relates to a preparation method and application of 5-norbornene-2-carbaldehyde. Background Art

[0002] As an intermediate for synthesizing 2-chloro-5-(chloromethyl)pyridine, 5-norbornene-2-carbaldehyde can be used to produce pesticide intermediates such as imidacloprid, acetamiprid, nitenpyram, and thiacloprid, and plays a crucial role in neonicotinoid insecticides. Its traditional synthesis method is a batch reaction. First, acrolein is added to the reactor, and then cyclopentadiene is added dropwise at -5°C to 0°C. The reaction has a large heat release, requires a long dropping time of 10 to 15 hours, has high heat removal energy consumption, and a holding reaction time of 6 - 10 hours. The reaction rate is slow. If the dropping rate is not properly controlled and is too fast, a large amount of materials will accumulate. With the heat release of the reaction, the heat cannot be transferred in time, the temperature rises, the reaction accelerates, and there is a risk of material overflow. Acrolein and cyclopentadiene are low-boiling, toxic, flammable, and explosive chemicals. The volatilized gas during the material overflow process will cause serious environmental pollution and pose a safety hazard to the health of personnel.

[0003] Chen Chao of Nanjing Tech University proposed in the article "Microreaction Process Study of 2-Cyanoethyl-5-norbornene-2-carbaldehyde" that the reaction is carried out at 60°C, 130°C, and 160°C in a microstructured reactor composed of a T-shaped three-way pipe and a residence time extension pipe. The raw material cyclopentadiene and the product 5-norbornene-2-carbaldehyde are thermosensitive substances, and they are prone to polymerization at high temperatures, resulting in a large amount of material loss and a large amount of waste generation.

[0004] CN107915611A adopts a two-stage series batch reaction. The reaction conversion rate in the first-stage reaction kettle is 92 - 96% based on acrolein, and the reaction conversion rate in the second-stage reaction kettle is 95 - 99.8% based on acrolein. This method still uses a reaction kettle. 92 - 96% of the reaction heat is released in the first kettle. This reaction has a large heat release and requires a very high heat exchange capacity of the reaction kettle.

[0005] Therefore, in order to solve the problem that the existing 5-norbornene-2-carbaldehyde synthesis process cannot balance the conversion rate of raw materials, the yield of the target product, and the stability and safety of the process, a new preparation method of 5-norbornene-2-carbaldehyde needs to be developed. Summary of the Invention

[0006] The object of the present invention is to overcome the problems existing in the existing 5-norbornene-2-carbaldehyde synthesis process, which cannot balance the conversion rate of raw materials, the yield of the target product, and the stability and safety of the process, and provide a preparation method and application of 5-norbornene-2-carbaldehyde.

[0007] To achieve the above object, on the one hand, the present invention provides a method for preparing 5-norbornene-2-carbaldehyde, characterized in that the method comprises: mixing cyclopentadiene and acrolein and successively carrying out a first-stage reaction and a second-stage reaction, wherein the temperature of the second-stage reaction is 5-15% higher than that of the first-stage reaction;

[0008] Among them, when the GC analysis shows that acrolein < 25 vol% and cyclopentadiene < 35 vol%, the temperature is raised to enter the second-stage reaction.

[0009] On the second aspect, the present invention provides the application of the method described in the first aspect of the present invention in at least one of improving the stability, safety and raw material conversion rate in the process of preparing 5-norbornene-2-carbaldehyde.

[0010] Through the above technical solutions, the preparation method provided by the present invention can improve the conversion rate of raw materials, the reaction rate and the yield of the target product, and can also improve the stability and safety of the synthesis process. Specific Embodiments

[0011] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0012] As mentioned above, on the one hand, the present invention provides a method for preparing 5-norbornene-2-carbaldehyde, characterized in that the method comprises: mixing cyclopentadiene and acrolein and successively carrying out a first-stage reaction and a second-stage reaction, wherein the temperature of the second-stage reaction is 5-15% higher than that of the first-stage reaction;

[0013] Among them, when the GC analysis shows that acrolein < 25 vol% and cyclopentadiene < 35 vol%, the temperature is raised to enter the second-stage reaction.

[0014] In some embodiments of the present invention, preferably, when the content of acrolein in the reaction system is 9-20 vol% and the content of cyclopentadiene is 14-30 vol%, the temperature is raised to enter the second-stage reaction.

[0015] In some embodiments of the present invention, preferably, the volume ratio of cyclopentadiene to acrolein is 1-4:1.

[0016] In some embodiments of the present invention, preferably, the volume ratio of cyclopentadiene to acrolein is 1-2:1.

[0017] In some embodiments of the present invention, preferably, the temperature of the first-stage reaction is 10-100 °C, preferably 40-70 °C, more preferably 55-65 °C. Within this temperature range, the yield of the target product 5-norbornene-2-carbaldehyde can be maximized; the time is 1-30 min, preferably 5-25 min.

[0018] In some embodiments of the present invention, preferably, the rate of temperature increase is 8-12%.

[0019] In some embodiments of the present invention, preferably, after the temperature increase, a heat preservation operation is also carried out.

[0020] In some embodiments of the present invention, preferably, the time of the second-stage reaction is 1-40 min, preferably 10-30 min.

[0021] In some embodiments of the present invention, preferably, the method further includes: cooling the system after the second-stage reaction is completed.

[0022] In some embodiments of the present invention, preferably, the rate of temperature decrease is 1-10 °C / min, more preferably 3-6 °C / min.

[0023] In some embodiments of the present invention, preferably, the cooling is to cool the system obtained after the temperature increase to 15-30 °C, preferably 20-28 °C.

[0024] In some embodiments of the present invention, preferably, the method further includes: performing constant temperature after cooling (maintaining at the stable temperature after the above cooling).

[0025] In some embodiments of the present invention, preferably, the time of the constant temperature is 0.5-3 h, preferably 1-2 h.

[0026] In the present invention, the method can be carried out by a continuous synthesis process, and the process can be carried out by a continuous reaction device, such as a tubular reactor.

[0027] In the present invention, the continuous reaction device further includes a heat insulator, a cooler and an aging kettle.

[0028] In the present invention, the first-stage reaction and the second-stage reaction are carried out in the tubular reactor, the heat preservation operation is carried out in the heat insulator, the cooling is carried out in the cooler, and the constant temperature is carried out in the aging kettle.

[0029] According to a particularly preferred embodiment of the present invention, the method comprises: carrying out a first-stage reaction for 5 - 15 min at 55 - 60 °C with a volume ratio of cyclopentadiene to acrolein of 1.3 - 1.7:1, raising the temperature by 8 - 9.5% and carrying out a second-stage reaction for 5 - 15 min until qualified (GC analysis shows acrolein < 15 v%), then cooling to 20 - 28 °C at a cooling rate of 4 °C / min and keeping the temperature constant for 1 - 2 h, which can maximize the yield of the target product 5-norbornene-2-carbaldehyde.

[0030] The second aspect of the present invention provides the application of the method described in one aspect of the present invention in improving at least one of the stability, safety and raw material conversion rate in the process of preparing 5-norbornene-2-carbaldehyde.

[0031] The present invention will be described in detail below through examples. In the following examples, the conversion rate parameter is calculated by the formula: reaction conversion rate (%) based on acrolein = 100% - acrolein content (v%) in the GC analysis of the sample taken from the aging kettle; the yield parameter is calculated by the formula: yield of 5-norbornene-2-carbaldehyde (%) = content of 5-norbornene-2-carbaldehyde (wt%) in the GC analysis of the sample taken from the aging kettle * total weight / theoretical production amount; unless otherwise specified, all raw materials are ordinary commercially available products.

[0032] GC analysis conditions:

[0033] Agilent 7820A, equipped with a hydrogen flame ionization detector and a capillary injection system

[0034] Chromatographic column: EN20 capillary gas chromatography column (30 × 0.32 × 0.5);

[0035] Column temperature: programmed temperature rise, 130 °C for 0 min;

[0036] 40 °C / min to 190 °C for 5 min;

[0037] 40 °C / min to 250 °C for 10 min;

[0038] Vaporization chamber temperature: 250 °C; Detection chamber temperature: 250 °C;

[0039] Gas flow rate (ml / min): hydrogen 30; air 300;

[0040] Tail blow: 25 ml / min; Column flow rate: 1.00 ml / min;

[0041] Split ratio: 30:1;

[0042] Stop time: 15 min; Injection volume: 0.2 μl.

[0043] Example 1

[0044] Start the stirring of the tubular reactor, and feed cyclopentadiene from the intermediate storage tank of cyclopentadiene and acrolein from the intermediate storage tank of acrolein. Set the feed rate of cyclopentadiene to 8.64 L / min and the feed rate of acrolein to 5.84 L / min. Open the cooling water inlet valve of the tubular reactor and maintain the reactor temperature at 60 °C. After reacting for 10 min (the first-stage reaction), the obtained material enters the incubator at a feed rate of 696 L / h and is kept at 65 °C for 10 min (the second-stage reaction) until it is qualified (GC analysis shows that acrolein < 15 v%). Then, it is cooled to 25 °C at a cooling rate of 4 °C / min by a cooler and enters the aging kettle. Start the stirring and keep the jacket cooling water at a constant temperature of 25 °C. Sampling and GC analysis at the outlet of the tubular reactor: acrolein 18.5 v%, cyclopentadiene 28.6 v%; sampling and GC analysis at the outlet of the incubator: acrolein 12.6 v%, cyclopentadiene 18.8 v%; sampling and GC analysis after keeping the aging kettle at a constant temperature for 2 h: acrolein 0.7 v%, cyclopentadiene 4 v%. The reaction conversion rate based on acrolein is 99.3%, and the yield of 5-norbornene-2-carbaldehyde is 95%.

[0045] Example 2

[0046] Start the stirring of the tubular reactor, and feed cyclopentadiene from the intermediate storage tank of cyclopentadiene and acrolein from the intermediate storage tank of acrolein. Set the feed rate of cyclopentadiene to 8.64 L / min and the feed rate of acrolein to 5.84 L / min. Open the cooling water inlet valve of the tubular reactor and maintain the reactor temperature at 55 °C. After reacting for 10 min (the first-stage reaction), the obtained material enters the incubator at a feed rate of 696 L / h and is kept at 60 °C for 10 min (the second-stage reaction) until it is qualified. Then, it is cooled to 25 °C at a cooling rate of 4 °C / min by a cooler and enters the aging kettle. Start the stirring and keep the jacket cooling water at a constant temperature of 25 °C. Sampling and GC analysis at the outlet of the tubular reactor: acrolein 9 v%, cyclopentadiene 14 v%; sampling and GC analysis at the outlet of the incubator: acrolein 5 v%, cyclopentadiene 9 v%; sampling and GC analysis after keeping the aging kettle at a constant temperature for 2 h: acrolein 0.8 v%, cyclopentadiene 3.2 v%. The reaction conversion rate based on acrolein is 99.2%, and the yield of 5-norbornene-2-carbaldehyde is 95%.

[0047] Example 3

[0048] Start the stirring of the tubular reactor, and feed cyclopentadiene from the intermediate storage tank of cyclopentadiene and acrolein from the intermediate storage tank of acrolein. Set the feed rate of cyclopentadiene to 8.64 L / min and the feed rate of acrolein to 5.84 L / min. Open the cooling water inlet valve of the tubular reactor and maintain the reactor temperature at 50 °C. After reacting for 10 min (the first-stage reaction), the obtained material enters the incubator at a feed rate of 696 L / h and is kept at 55 °C for 10 min (the second-stage reaction) until it is qualified. Then, it is cooled to 25 °C at a cooling rate of 4 °C / min by a cooler and enters the aging kettle. Start the stirring and keep the jacket cooling water at a constant temperature of 25 °C. Take samples from the outlet of the tubular reactor for GC analysis: acrolein 17.5 v%, cyclopentadiene 26.5 v%; take samples from the outlet of the incubator for GC analysis: acrolein 10.8 v%, cyclopentadiene 16.8 v%; take samples from the aging kettle after keeping it at a constant temperature for 2 h for GC analysis: acrolein 1.2 v%, cyclopentadiene 5 v%. The reaction conversion rate based on acrolein is 98.8%, and the yield of 5-norbornene-2-carbaldehyde is 92%.

[0049] Example 4

[0050] Start the stirring of the tubular reactor, and feed cyclopentadiene from the intermediate storage tank of cyclopentadiene and acrolein from the intermediate storage tank of acrolein. Set the feed rate of cyclopentadiene to 8.64 L / min and the feed rate of acrolein to 5.84 L / min. Open the cooling water inlet valve of the tubular reactor and maintain the reactor temperature at 80 °C. After reacting for 10 min (the first-stage reaction), the obtained material enters the incubator at a feed rate of 696 L / h and is kept at 88 °C for 10 min (the second-stage reaction) until it is qualified. Then, it is cooled to 25 °C at a cooling rate of 6 °C / min by a cooler and enters the aging kettle. Start the stirring and keep the jacket cooling water at a constant temperature of 25 °C. Take samples from the outlet of the tubular reactor for GC analysis: acrolein 19.5 v%, cyclopentadiene 24.5 v%; take samples from the outlet of the incubator for GC analysis: acrolein 15.5 v%, cyclopentadiene 14.2 v%; take samples from the aging kettle after keeping it at a constant temperature for 2 h for GC analysis: acrolein 5.9 v%, cyclopentadiene 2 v%. The reaction conversion rate based on acrolein is 94.1%, and the yield of 5-norbornene-2-carbaldehyde is 88%.

[0051] Example 5

[0052] Carry out according to the method of Example 1, except that the reaction time of the tubular reactor is 40 min. Take samples from the outlet of the tubular reactor for GC analysis: acrolein 10.5 v%, cyclopentadiene 18.3 v%; take samples from the outlet of the incubator for GC analysis: acrolein 5.6 v%, cyclopentadiene 10.5 v%; take samples from the aging kettle after keeping it at a constant temperature for 2 h for GC analysis: acrolein 0.5 v%, cyclopentadiene 3.8 v%. The reaction conversion rate based on acrolein is 99.5%, and the yield of 5-norbornene-2-carbaldehyde is 85%.

[0053] Example 6

[0054] It was carried out according to the method of Example 1, except that the cooling rate was 0.1 °C / min. GC analysis of the sample taken at the outlet of the tubular reactor showed: acrolein 18.5 v%, cyclopentadiene 28.6 v%; GC analysis of the sample taken at the outlet of the incubator showed: acrolein 12.6 v%, cyclopentadiene 18.8 v%; GC analysis of the sample taken after 2 h of constant temperature in the aging kettle showed: acrolein 0.1 v%, cyclopentadiene 3.5 v%. The reaction conversion rate based on acrolein was 99.9%, and the yield of 5-norbornene-2-carbaldehyde was 88%.

[0055] Example 7

[0056] It was carried out according to the method of Example 1, except that the constant temperature time was 4 h. GC analysis of the sample taken at the outlet of the tubular reactor showed: acrolein 18.4 v%, cyclopentadiene 28.5 v%; GC analysis of the sample taken at the outlet of the incubator showed: acrolein 12.5 v%, cyclopentadiene 18.6 v%; GC analysis of the sample taken after 4 h of constant temperature in the aging kettle showed: acrolein 0 v%, cyclopentadiene 2 v%. The reaction conversion rate based on acrolein was 100 v%, and the yield of 5-norbornene-2-carbaldehyde was 87%.

[0057] Comparative Example 1

[0058] It was carried out according to the method of Example 1, except that the temperature of the incubator was 50 °C. GC analysis of the sample taken at the outlet of the tubular reactor showed: acrolein 18.5 v%, cyclopentadiene 28.5 v%; GC analysis of the sample taken at the outlet of the incubator showed: acrolein 18.5 v%, cyclopentadiene 28.5 v%; GC analysis of the sample taken after 2 h of constant temperature in the aging kettle showed: acrolein 3 v%, cyclopentadiene 10 v%. The reaction conversion rate based on acrolein was 97%, and the yield of 5-norbornene-2-carbaldehyde was 79%.

[0059] Comparative Example 2

[0060] It was carried out according to the method of Example 1, except that the temperatures of the tubular reactor and the incubator were exchanged. GC analysis of the sample taken at the outlet of the tubular reactor showed: acrolein 10.5 v%, cyclopentadiene 30.2 v%; GC analysis of the sample taken at the outlet of the incubator showed: acrolein 5.2 v%, cyclopentadiene 25.2 v%; GC analysis of the sample taken after 2 h of constant temperature in the aging kettle showed: acrolein 0.1 v%, cyclopentadiene 18 v%. The reaction conversion rate based on acrolein was 99.9%, and the yield of 5-norbornene-2-carbaldehyde was 56%.

[0061] Comparative Example 3

[0062] The method of Example 1 was followed, except that the temperatures of the tubular reactor and the heat-insulated kettle were both 50 °C. GC analysis of the sample taken from the outlet of the tubular reactor showed: acrolein 28 v%, cyclopentadiene 35 v%; GC analysis of the sample taken from the outlet of the heat-insulator showed: acrolein 18 v%, cyclopentadiene 25 v%; GC analysis of the sample taken after 2 h of constant temperature in the aging kettle showed: acrolein 10 v%, cyclopentadiene 15 v%. The reaction conversion rate based on acrolein was 90%, and the yield of 5-norbornene-2-carbaldehyde was 50%.

[0063] From the results of the examples and comparative examples, it can be seen that compared with the comparative examples, the examples adopting the technical solution of the present invention have beneficial effects such as high raw material conversion rate, high reaction rate, and high yield of the target product. At the same time, compared with the prior art, the present invention has the advantages of less material loss, less waste generated, lower requirement for the heat exchange capacity of the reaction kettle, easy availability of raw materials, low production cost, high product purity, small amount of three wastes, no sulfur-containing waste generated, and easy treatment of wastewater. Moreover, the method of the present invention has high safety and stability.

[0064] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing 5-norbornene-2-carbaldehyde, characterized in that, The method includes: mixing cyclopentadiene and acrolein and successively carrying out a first-stage reaction and a second-stage reaction, wherein the temperature of the second-stage reaction is 5-15% higher than that of the first-stage reaction; Among them, when the content of acrolein in the reaction system < 25 vol%, and the content of cyclopentadiene < 35 vol%, the temperature is raised to enter the second-stage reaction.

2. The method according to claim 1, wherein, When the content of acrolein in the reaction system is 9-20 vol%, and the content of cyclopentadiene is 14-30 vol%, the temperature is raised to enter the second-stage reaction; And / or, the volume ratio of cyclopentadiene to acrolein is 1-4:1, preferably 1-2:

1.

3. The method according to claim 1 or 2, wherein The temperature of the first-stage reaction is 10-100 °C, preferably 40-70 °C; the time is 1-30 min, preferably 5-25 min.

4. The method according to any one of claims 1 to 3, wherein, The temperature of the second-stage reaction is 8-12% higher than that of the first-stage reaction.

5. The method according to any one of claims 1-4, wherein, The time of the second-stage reaction is 1-40 min, preferably 10-30 min.

6. The method according to any one of claims 1-5, wherein, The method further includes: cooling the system after the second-stage reaction; Preferably, the cooling rate of the cooling is 1-10 °C / min, more preferably 3-6 °C / min.

7. The method according to claim 6, wherein The cooling is to cool the system after the second-stage reaction to 15-30 °C, preferably 20-28 °C.

8. The method according to claim 6 or 7, wherein The method further includes: carrying out constant temperature after cooling.

9. The method according to claim 8, wherein, The time of the constant temperature is 0.5-3 h, preferably 1-2 h.

10. Use of the method according to any one of claims 1-9 in improving at least one of stability, safety and raw material conversion rate in the process of preparing 5-norbornene-2-carbaldehyde.