Method for efficiently preparing succinaldehyde

Abstract

Disclosed in the present invention is a method for efficiently preparing succinaldehyde. A microchannel reactor is used, and the method comprises the following steps: step 1, constructing a microchannel reactor system, the microchannel reactor system comprising a feeding module, a microchannel reaction module, a temperature control module, and a product collection module; and step 2, separately pumping an aqueous solution containing a catalyst and 2,5-dimethoxytetrahydrofuran into the microchannel reaction module by means of the feeding module and mixing for reaction to obtain a succinaldehyde aqueous solution, wherein the catalyst is trifluoroacetic acid and 2,2,6,6-tetramethylpiperidine oxide. In the method for preparing succinaldehyde as provided by the present invention, a microchannel reactor is used, and the present invention has a fully automated production process, high control accuracy, a safe and stable reaction process, easy operation, low production costs, and a short reaction time, and achieves a high content of succinaldehyde in the resulting succinaldehyde aqueous solution. The use of a combined catalyst (trifluoroacetic acid + Tempo) effectively shortens the reaction time, and also inhibits the generation of by-products.

Description

Method for efficiently preparing butanedial TECHNICAL FIELD

[0001] The present application relates to the technical field of butanedial preparation, and particularly relates to a method for efficiently preparing butanedial. BACKGROUND

[0002] Butanedial is an important fine chemical (pharmaceutical) intermediate, and is particularly related to the synthesis of the pesticide oxadiazyl. At present, the main industrial production method is to use 2,5-dimethoxy tetrahydrofuran as a raw material, and then to further perform a heating hydrolysis reaction, remove the reaction solvent by evaporation under reduced pressure, and obtain butanedial after concentration. This method has the disadvantages of high cost of raw materials, generation of a large amount of wastewater, long time consumption, and difficulty in large-scale production.

[0003] In addition, butanedial has low stability, and is prone to produce high polymers during storage and transportation, and thus deteriorates. In particular, the hydrolysis reaction of butanedial itself is a reversible reaction, and long-time placement leads to a great reduction in the content of butanedial. Therefore, butanedial needs to be prepared immediately before use, and the industrial operation is complicated, which is not conducive to industrialization.

[0004] Therefore, it is a research focus in the field to seek a butanedial synthesis method which is smooth in process, economic and environmentally friendly, conducive to storage and transportation, and high in atomic utilization rate. SUMMARY

[0005] The present application aims at the deficiencies in the prior art, and provides a method for efficiently synthesizing butanedial.

[0006] To achieve the above-mentioned object, the technical solution adopted by the present application is as follows:

[0007] The present application provides a method for efficiently preparing butanedial, which adopts a micro-channel reactor and includes the following steps:

[0008] Step one, constructing a micro-channel reactor system, wherein the micro-channel reactor system includes a feeding module, a micro-channel reaction module, a temperature control module, and a product collection module;

[0009] Step two, pumping a water solution containing a catalyst and 2,5-dimethoxy tetrahydrofuran into the micro-channel reaction module through the feeding module respectively, mixing and reacting to obtain a butanedial water solution, and collecting the butanedial water solution by the product collection module;

[0010] The catalyst is trifluoroacetic acid and 2,2,6,6-tetramethylpiperidine oxide (Tempo).

[0011] Further, the mass of trifluoroacetic acid is 0.01-30% of the mass of 2,5-dimethoxy tetrahydrofuran, and the mass of 2,2,6,6-tetramethylpiperidine oxide is 0.01-5% of the mass of 2,5-dimethoxy tetrahydrofuran.

[0012] Further, the trifluoroacetic acid is 0.1-0.5% of the mass of 2,5-dimethoxytetrahydrofuran, and the 2,2,6,6-tetramethylpiperidine oxide is 0.05-0.2% of the mass of 2,5-dimethoxytetrahydrofuran.

[0013] Further, the flow rate ratio of the 2,5-dimethoxytetrahydrofuran to the aqueous solution containing the catalyst is v:v = 1:(1-3).

[0014] Further, the flow rate ratio of the 2,5-dimethoxytetrahydrofuran to the aqueous solution containing the catalyst is v:v = 1:3.

[0015] Further, in the second step, the temperature of the micro-channel reaction module is controlled at 70-160℃, and the outlet pipeline of the delay coil is connected to a back pressure valve of 5-40 psi.

[0016] Further, in the second step, the temperature of the micro-channel reaction module is controlled at 140℃, and the outlet pipeline of the delay coil is connected to a back pressure valve of 20 psi.

[0017] The above technical scheme is adopted in the present application, and compared with the prior art, the present application has the following technical effects:

[0018] The butanedialdehyde preparation method provided by the present application adopts a micro-channel reactor, the production process is fully automated, the control precision is accurate, the reaction process is safe and stable, easy to operate, the production cost is low, the reaction time is short, and the content of the obtained butanedialdehyde aqueous solution is high.

[0019] The butanedialdehyde preparation method provided by the present application adopts a combined catalyst (trifluoroacetic acid+Tempo), which not only effectively shortens the reaction time, but also inhibits the generation of by-products; especially in the butanedialdehyde aqueous solution, without the complicated post-treatment operation of water removal to suppress the reverse of the reversible reaction; a small amount of Tempo not only acts as an oxidizing agent, but also highlights its polymerization inhibition effect in an acidic environment, that is, effectively prevents intermolecular reactions and reduces intramolecular reactions.

[0020] The butanedialdehyde preparation method provided by the present application effectively avoids a large amount of wastewater, does not need to be distilled or rectified, has low energy consumption, high atomic utilization rate, is easy to store and transport, and is friendly to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0021] Fig. 1 is a schematic diagram of the micro-channel reactor system of the present application;

[0022] [Corrected according to Rule 91 on 12.06.2025] Fig. 2 is a gas chromatogram of the butanedialdehyde product in Example 1.

[0023] [Corrected according to Rule 91 12.06.2025] Wherein the reference signs are: 1 - raw material tank; 2 - constant flow pump; 3 - micro-channel reaction module; 4 - temperature control device; 5 - delay coil; 6 - collection tank. DETAILED DESCRIPTION

[0024] The application will be further described below in conjunction with the drawings and specific examples, but not as a limitation of the application. It should be noted that the examples in the application and the features in the examples can be combined with each other without conflict.

[0025] The application provides a method for efficiently preparing butanedial, using a micro-channel reactor (referring to Fig. 1), comprising the following steps:

[0026] Step one, constructing a micro-channel reactor system, the micro-channel reactor system comprising a feed module, a micro-channel reaction module 3, a temperature control module and a product collection module;

[0027] Step two, pumping the aqueous solution containing the catalyst and 2,5-dimethoxytetrahydrofuran into the micro-channel reaction module 3 through the feed module respectively, mixing and reacting to obtain butanedial aqueous solution, which is collected by the product collection module;

[0028] The catalyst is trifluoroacetic acid and 2,2,6,6-tetramethylpiperidine oxide (Tempo).

[0029] In the application, the feed module comprises two raw material tanks 1 and two constant flow pumps 2, each raw material tank 1 is connected with one constant flow pump 2 through a pipeline, and then connected with the feed port of the micro-channel reaction module 3 through a pipeline.

[0030] In the application, the product collection module comprises a delay coil 5 and a collection tank 6 connected with the outlet pipeline of the micro-channel reaction module 3 in sequence.

[0031] As a preferred example, the mass of trifluoroacetic acid is 0.01-30% of the mass of 2,5-dimethoxytetrahydrofuran, more preferably 0.1-0.5%; the mass of 2,2,6,6-tetramethylpiperidine oxide is 0.01-5% of the mass of 2,5-dimethoxytetrahydrofuran, more preferably 0.05-0.2%.

[0032] As a preferred example, the flow rate ratio of 2,5-dimethoxytetrahydrofuran to the aqueous solution containing the catalyst is v:v = 1:(1-3), more preferably v:v = 1:3.

[0033] In the application, the temperature control module comprises a temperature control device 4, which controls the temperature of the micro-channel reaction module 3 at 70-160℃, more preferably 140℃.

[0034] In the present application, a back pressure valve of 5-40 psi, more preferably 20 psi, is arranged on the discharge pipeline of the time delay coil 5.

[0035] Example 1

[0036] The present embodiment provides a method for efficiently preparing butanedial, which uses a micro-channel reactor (see FIG. 1), and the specific steps are as follows:

[0037] In a 50 mL round-bottom flask, 2,5-dimethoxytetrahydrofuran (5 g) is weighed, which is material x. In another 50 mL round-bottom flask, purified water (6 g), trifluoroacetic acid (0.025 g), and Tempo (5.0´10 -3 g) are weighed, which is material y. Then, the two are respectively pumped into the micro-channel reaction module through a constant flow pump, the flow rate ratio between the two is controlled at v(x):v(y)=1:3, the pipeline temperature is controlled at 140°C, a back pressure valve of 20 psi is connected, and after the mixed reaction, butanedial aqueous solution is obtained.

[0038] The quantitative yield of butanedial is determined by gas phase internal standard quantitative method. Specifically, 250 mg of internal standard and 200 mg of butanedial aqueous solution are accurately weighed and dissolved in a 10 mL volumetric flask with a solvent. The calculation method is (butanedial peak area / internal standard peak area) / butanedial standard peak area´standard concentration ratio´(250 mg / 200 mg). The quantitative yield of butanedial is 95%, and the chromatogram is shown in FIG. 2. No obvious impurity peak is observed by gas phase detection, that is, no γ-butyrolactone is generated. The reaction liquid is placed at room temperature for 8 hours, and no obvious high polymer is generated by liquid phase GPC detection. The liquid phase quantitative yield is determined by the above method to be 94%, which is basically not lost, greatly reducing the difficulty of storage.

[0039] Example 2

[0040] The present embodiment provides a method for efficiently preparing butanedial, which uses a micro-channel reactor (see FIG. 1), and the specific steps are as follows:

[0041] In a 50 mL round-bottom flask, 2,5-dimethoxytetrahydrofuran (5 g) is weighed, which is material x. In another 50 mL round-bottom flask, purified water (6 g), trifluoroacetic acid (0.025 g), and Tempo (5.0´10 -3 g) are weighed, which is material y. Then, the two are respectively pumped into the micro-channel reaction module through a constant flow pump, the flow rate ratio between the two is controlled at v(x):v(y)=1:3, the pipeline temperature is controlled at 140°C, a back pressure valve of 20 psi is connected, and after the mixed reaction, butanedial aqueous solution is obtained.

[0042] The quantitative yield of butanedial is determined by gas phase internal standard quantitative method. Specifically, 250 mg of internal standard and 200 mg of butanedial aqueous solution are accurately weighed and dissolved in a 10 mL volumetric flask with a solvent. The calculation method is (butanedial peak area / internal standard peak area) / butanedial standard peak area´standard concentration ratio´(250 mg / 200 mg). The quantitative yield of butanedial is 95%, and the chromatogram is shown in FIG. 2. No obvious impurity peak is observed by gas phase detection, that is, no γ-butyrolactone is generated. The reaction liquid is placed at room temperature for 8 hours, and no obvious high polymer is generated by liquid phase GPC detection. The liquid phase quantitative yield is determined by the above method to be 94%, which is basically not lost, greatly reducing the difficulty of storage.

[0043] Example 3

[0044] The present embodiment provides a method for efficiently preparing butanedial, which uses a micro-channel reactor (see FIG. 1), and the specific steps are as follows:

[0045] In a 500 mL round-bottom flask, 2,5-dimethoxytetrahydrofuran (100 g) was weighed, which was material x. In another 500 mL round-bottom flask, pure water (130 g), trifluoroacetic acid (0.5 g), and Tempo (0.2 g) were weighed, which was material y. Then, the two were pumped into the micro-channel reaction module through constant flow pumps, respectively, and the flow rate ratio between the two was controlled at v(x):v(y)=1:3. The pipeline temperature was controlled at 140°C, and a back pressure valve of 20 psi was connected. After the mixed reaction, butanedial aqueous solution was obtained.

[0046] The quantitative yield of butanedial was determined by gas phase internal standard quantitative method, and the quantitative yield of butanedial was 94%.

[0047] The above merely describes the preferred embodiments of the present application, and does not limit the implementation and protection scope of the present application. It should be realized by those skilled in the art that any equivalent replacement and obvious changes made according to the content of the present application and the drawings should be included in the protection scope of the present application.

Claims

1. A method for efficiently producing succindialdehyde, characterized by, The micro-channel reactor is used, comprising the following steps: Step one, constructing a micro-channel reactor system, which comprises a feeding module, a micro-channel reaction module, a temperature control module and a product collection module; Step two, pumping the water solution containing catalyst and 2,5-dimethoxytetrahydrofuran into the micro-channel reaction module through the feeding module respectively, mixing and reacting to obtain a butanedialdehyde water solution, which is collected by the product collection module; The catalyst is trifluoroacetic acid and 2,2,6,6-tetramethylpiperidine oxide.

2. The method for efficiently producing succindialdehyde according to claim 1, wherein, The mass of trifluoroacetic acid is 0.01-30% of the mass of 2,5-dimethoxytetrahydrofuran, and the mass of 2,2,6,6-tetramethylpiperidine oxide is 0.01-5% of the mass of 2,5-dimethoxytetrahydrofuran.

3. The method of efficiently producing succindialdehyde according to claim 2, wherein, The mass of trifluoroacetic acid is 0.1-0.5% of the mass of 2,5-dimethoxytetrahydrofuran, and the mass of 2,2,6,6-tetramethylpiperidine oxide is 0.05-0.2% of the mass of 2,5-dimethoxytetrahydrofuran.

4. The method of efficiently producing succindialdehyde according to claim 1, wherein, The flow rate ratio of 2,5-dimethoxytetrahydrofuran to the water solution containing catalyst is v:v=1:(1-3).

5. The method of efficiently producing succindialdehyde according to claim 4, wherein, The flow rate ratio of 2,5-dimethoxytetrahydrofuran to the water solution containing catalyst is v:v=1:

3.

6. The method for efficiently producing succindialdehyde according to claim 1, wherein In step two, the temperature of the micro-channel reaction module is controlled at 70-160℃, and the outlet pipeline of the delay coil is connected with a back pressure valve of 5-40 psi.

7. The method of efficiently producing succindialdehyde according to claim 6, wherein, In step two, the temperature of the micro-channel reaction module is controlled at 140℃, and the outlet pipeline of the delay coil is connected with a back pressure valve of 20 psi.

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