External circulation heterogeneous continuous synthesis method of methyl ethyl ketazine

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly discloses an outer circulation heterogeneous continuous synthesis method of methyl ethyl ketazine, which comprises the following steps: S1, preparing a first working solution from a catalyst and water; s2, dissolving a cocatalyst and a stabilizer in a hydrogen peroxide solution to form a second working solution; s3, butanone, the first working solution and the second working solution are mixed and then continuously enter a circulation reactor, and circulation of the mixed working solution is kept; ammonia gas is continuously introduced into the mixed working solution in the loop reactor, the reaction temperature is controlled to be 40-55 DEG C, along with the reaction, the liquid level in the reactor continuously rises, an oil-phase product overflows from a reaction system in time, and the product is separated and collected. According to the method, the continuous synthesis of the product is realized by utilizing the characteristic that the product methyl ethyl ketazine is insoluble in a water phase system, the synthesis reaction time is shortened, the production efficiency is improved, oxidation side reactants are reduced, and the yield of the methyl ethyl ketazine is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and particularly relates to a method for continuously synthesizing outer-loop non-homogeneous butanone hydrazone. Background Art

[0002] Hydrazine hydrate is an important chemical raw material and a widely used chemical product. It is an important raw material for the production of foaming agents, pesticides, pharmaceuticals, dyes, developers, and reducing agents. It is also used in the manufacture of high-purity metals, synthetic fibers, separation of rare elements, deoxidation of large boiler feed water, production of rocket fuels and explosives, etc. There are mainly four methods for the industrial production of hydrazine hydrate, namely the Rasching method, the ketazine method of Bayer Company, the urea method, and the hydrogen peroxide method of PCUK Company.

[0003] In the production of hydrazine hydrate by the hydrogen peroxide method, hydrogen peroxide is used as an oxidant, nitrile or amide is used as a catalyst, and sodium phosphate salt and ammonium carboxylate are used as co-catalysts. Butanone and ammonia react with hydrogen peroxide to form the intermediate butanone hydrazone, which is then hydrolyzed to produce hydrazine hydrate. The advantages of this method are that it does not produce by-products of strongly corrosive chlorides and has low energy consumption, making it an energy-saving and environmentally friendly green production process.

[0004] In the traditional production process of hydrazine hydrate by the hydrogen peroxide method, the reactor for synthesizing the intermediate butanone hydrazone is a batch reactor. The operation steps are to sequentially add butanone, catalyst and co-catalyst, ammonia gas, and hydrogen peroxide. During the preparation process, the generated butanone hydrazone is insoluble in water. Butanone hydrazone dissolves butanone to form an oil phase, which is separated into two phases with the aqueous working solution containing the catalyst. In the traditional production process of the hydrogen peroxide method, the oil phase and the water phase are separated only after the reaction is completed, and then the oil phase is subsequently purified and hydrolyzed to produce hydrazine hydrate. During the reaction process, the oil phase is not removed from the reaction system in a timely manner, and the generated butanone hydrazone is easily further oxidized and decomposed by hydrogen peroxide in the aqueous phase, thus reducing the yield of butanone hydrazone; in addition, due to the relatively weak reaction activity of the catalyst, during the reaction process, the concentration of hydrogen peroxide decreases after consumption in the initial stage of the reaction, further weakening the reaction rate and prolonging the reaction time. Therefore, the intermittent synthesis reaction requires a longer time. The reaction time also prolongs the contact between the oxide and butanone hydrazone, resulting in deep oxidation of the product and reducing the product yield.

[0005] Therefore, in view of the above-described technical problems, there is an urgent need for a reaction method that can shorten the reaction time and enable continuous synthesis. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for continuously synthesizing outer-loop non-homogeneous butanone hydrazone, which can shorten the synthesis reaction time, improve the yield of butanone hydrazone, and reduce the occurrence of oxidation side reactions.

[0007] To solve the above technical problems, the technical solution of the present invention is as follows: Improve the traditional hydrazine hydrate production process by hydrogen peroxide method, change from batch production to continuous production, use a loop reactor for heterogeneous continuous synthesis, strengthen the mass transfer of gas-liquid or liquid-liquid two phases in the reaction, and improve the reaction rate; The product butanone azine is separated and removed from the reaction system in time to avoid the product being oxidized by hydrogen peroxide.

[0008] A method for heterogeneous continuous synthesis of butanone azine in an outer loop, specifically comprising the following steps: S1. Prepare a first working solution by mixing a catalyst and water; S2. Dissolve a cocatalyst and a stabilizer in a hydrogen peroxide solution to form a second working solution; S3. After mixing butanone, the first working solution, and the second working solution, continuously feed them into the loop reactor, start the stirrer and the circulation pump to keep the mixed working solution in circulation; continuously introduce ammonia gas into the mixed working solution in the loop reactor, control the reaction temperature at 40-55 °C, and the generated butanone azine is insoluble in water. After the product butanone azine dissolves butanone, an oil phase is formed. Under the action of gravity and air flotation, the oil-water two phases flow upward in a staggered manner; as the reaction proceeds, the liquid level in the loop reactor continues to rise, the oil phase floats away from the water phase, and the oil phase product overflows from the reaction system in time, and the product is separated and collected.

[0009] The reaction equation is as follows: 2NH3 + H2O2 + 2CH3COC2H5 → CH3(C2H5)C=N-N=C(C2H5)CH3 + 4H2O Preferably, in step S1, the catalyst is an amide and its corresponding carboxylate salt, such as a formamide and ammonium formate system, or an acetamide and ammonium acetate system.

[0010] Preferably, in step S2, the cocatalyst is disodium hydrogen phosphate.

[0011] Preferably, in step S2, the stabilizer is disodium ethylenediaminetetraacetate (EDTA-2Na).

[0012] Preferably, in step S2, the concentration of the hydrogen peroxide solution is 25-70 wt%.

[0013] Preferably, in step S2, the mass ratio of the cocatalyst to the hydrogen peroxide solution is 0.1-2%; the mass ratio of the stabilizer to the hydrogen peroxide solution is 0.1-2%.

[0014] Preferably, in step S3, during the reaction process, control the molar ratio of butanone to the hydrogen peroxide solution to be 1-5:1; the molar ratio of ammonia to the hydrogen peroxide solution to be 1-10:1; the molar ratio of the catalyst to the hydrogen peroxide solution to be 1-5:1.

[0015] Preferably, a turbine agitator is used for stirring in the circulation reactor, and the rotation speed is 100 - 2000 rpm, preferably 500 - 1000 rpm.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: (1) Through the rapid flow of materials, the mass transfer of gas-liquid or liquid-liquid two phases in the reaction process is accelerated, and the reaction rate is increased; under the action of stirring, the oil and water phases are radially mixed in the reaction liquid, and then driven by gravity and air flotation, the oil and water phases flow upward in a staggered manner. As the reaction proceeds, the liquid level in the circulation reactor continues to rise, and the oil phase floats up and separates from the water phase. The oil-phase product overflows from the reaction system in a timely manner, and the product is separated and collected.

[0017] (2) By utilizing the characteristic that the product butanone hydrazone is insoluble in the aqueous phase system, the continuous synthesis of the product and the stable separation of the oil-phase product and the aqueous-phase working fluid are realized, the synthesis reaction time is shortened, and the production efficiency is improved.

[0018] (3) In the continuous production of this method, hydrogen peroxide is continuously fed, which can ensure that a relatively high concentration of hydrogen peroxide is maintained in the main reaction zone, which is beneficial to accelerating the reaction rate and shortening the reaction time. Ammonia is sprayed into the reactor from the bottom in a dispersed manner to ensure the ammonia concentration in the reaction system. At the same time, it promotes the increase of the upward velocity difference between butanone hydrazone and the aqueous phase, which is beneficial to the separation of the product, reduces the contact between the product and hydrogen peroxide, reduces the oxidation side reaction of the product, and improves the product yield.

[0019] (4) The butanone hydrazone generated during the reaction process can be separated and removed from the reaction liquid in a timely manner, thereby effectively preventing the product from being oxidized by hydrogen peroxide, reducing the oxidation side reactants, and improving the yield of butanone hydrazone.

[0020] (5) The working fluid flowing rapidly under the action of an external circulation pump as a reaction raw material can dilute the reaction heat, and then the reaction heat is removed through a heat exchange device, which is beneficial to maintaining the temperature stability in the reaction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The following drawings are only intended to illustrate and explain the present invention schematically and do not limit the scope of the present invention. Among them: Figure 1 is a schematic process flow diagram of an embodiment of the present invention; Figure 2 is a schematic structural diagram of a working fluid injector in an embodiment of the present invention; Figure 3 is a schematic structural diagram of a gas distributor in an embodiment of the present invention; Figure 4 is a schematic diagram of the state of the liquid in the reactor body.

[0022] In the figure: 1 - Reactor body; 2 - Outer circulation pipe; 3 - Turbine agitator; 4 - Circulation pump; 5 - Static mixer; 6 - Working fluid injector; 7 - Gas phase distributor; 8 - Overflow port; 9 - Oil-gas-water three-phase separator; 10 - Heat exchanger; 11 - Main reaction zone; 12 - Secondary reaction zone; 13 - Overflow zone. Detailed implementation mode

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the following detailed description, only some exemplary embodiments of the present invention are described by way of illustration. It is understood that those of ordinary skill in the art can recognize that the described embodiments can be modified in various different ways without departing from the spirit and scope of the present invention. Therefore, the drawings and description are illustrative in nature and not intended to limit the scope of protection of the claims.

[0024] Example 1 A method for the outer circulation heterogeneous continuous synthesis of butanone hydrazone uses a heterogeneous continuous synthesis circulation reactor to strengthen the mass transfer of gas-liquid or liquid-liquid two phases in the reaction and improve the reaction rate; the product butanone hydrazone is separated and removed from the reaction system in a timely manner to avoid the product being oxidized by hydrogen peroxide.

[0025] Reference Figures 1 to 3 , the circulation reactor includes a reactor body 1, an outer circulation pipe 2 communicating with the inside of the reactor is arranged at the bottom of the reactor body 1, a circulation pump 4 and a static mixer 5 are arranged on the pipeline of the outer circulation pipe 2, and a working fluid injector 6 extending into the bottom of the reactor body 1 is installed at the end of the outer circulation pipe 2. The working fluid injector 6 can be realized by using common structures such as a Venturi tube, a vortex injection tube or a nozzle, etc. to realize the injection of the working fluid; a turbine agitator 3 is arranged in the reactor body 1, and an annular gas phase distributor 7 is arranged at the bottom of the reactor body 1. The gas phase distributor 7 is provided with an ammonia inlet and a plurality of downward spray holes distributed circumferentially, and an overflow port 8 is arranged at the top of the reactor body 1 (about 75% of the height of the reactor), and the overflow port 8 is connected to an oil-gas-water three-phase separator 9 through a discharge pipeline.

[0026] The synthesis method specifically includes the following steps: S1. Prepare a first working fluid by mixing formamide, ammonium formate and water in a mass ratio of 37.0%, 36.0% and 27%; S2. Dissolve disodium hydrogen phosphate and EDTA-2Na in a hydrogen peroxide solution (27.5 wt%) in a mass ratio of 0.2% and 0.5% respectively to form a second working fluid; S3. At a flow rate of 120 mol / h each, add methyl ethyl ketone and the first working fluid into the reactor body 1 from the bottom outer circulation pipe 2 of the reactor body 1. Start the turbine stirrer 3 and the circulation pump 4, and maintain the external circulation flow rate of the working fluid at 400 L / h and the stirrer speed at 700 rpm. Continuously introduce ammonia gas into the mixed working fluid in the reactor body 1 at a flow rate of 2.8 M3 / h. Pump the second working fluid into the static mixer 5 at a flow rate of 30 mol / h. After the second working fluid is fully mixed with methyl ethyl ketone and the first working fluid, it is sprayed into the bottom of the reactor body 1 through the working fluid ejector 6 and is completely backmixed with the ammonia gas coming out of the annular gas distributor 7 to ensure the ammonia concentration in the reaction system. Refer to Figure 4 , at the bottom of the reactor body 1 is the main reaction zone 11, where the synthesis reaction proceeds rapidly. The butanone hydrazone produced by the reaction is insoluble in water, and the product butanone hydrazone floats up and separates from the water phase after dissolving methyl ethyl ketone. The product floats up into the secondary reaction zone 12 in the reactor body 1. Under the action of the turbine stirrer 3, the oil and water phases are radially mixed, and under the action of gravity and air flotation, the oil and water phases flow upward in a staggered manner. As the reaction proceeds, the liquid level in the reactor continues to rise, and the oil phase gradually floats up and separates from the water phase and enters the overflow zone 13. The oil-phase product in the upper part of the liquid level overflows from the overflow port 8 at the top of the reactor in a timely manner and enters the oil-gas-water three-phase separator 9 for separation and collection. Detect the butanone hydrazone content in the oil phase and the water phase respectively, and calculate the yield to be 90.1% (the yield of butanone hydrazone is calculated based on the feeding amount of hydrogen peroxide, the same below).

[0027] During the above reaction process, control the reaction temperature at 40 - 55 °C.

[0028] In order to better control the reaction temperature, a heat exchanger 10 can be set on the working fluid circulation path. The working fluid coming out of the reactor enters the heat exchanger 10 through the circulation pump 4, and part of the reaction heat is released after the working fluid exchanges heat with the coolant. Of course, the reaction temperature can also be controlled by setting a jacket on the outside of the reactor body 1, etc., which should all fall within the protection scope of the present invention.

[0029] Example 2 Refer to Figure 1 , a method for the outer circulation heterogeneous continuous synthesis of butanone hydrazone, comprising the following steps: S1. Prepare the first working fluid by mixing acetamide, ammonium acetate and water in a mass ratio of 40.0%, 31.0%, and 29%. S2. Dissolve disodium hydrogen phosphate and EDTA-2Na in a hydrogen peroxide solution (27.5 wt%) in mass ratios of 0.3% and 0.7% respectively to form the second working fluid. S3. Respectively add methyl ethyl ketone and the first working fluid into the reactor from the bottom outer circulation pipe 2 of the reactor body 1 at a flow rate of 100 mol / h. Start the turbine stirrer 3 and the circulation pump 4, and maintain the external circulation flow rate of the working fluid at 350 L / h and the stirrer speed at 900 rpm. Continuously introduce ammonia gas into the mixed working fluid in the reactor at a flow rate of 2.6 M3 / h. Pump the second working fluid into the static mixer 5 at a flow rate of 25 mol / h. After the second working fluid is fully mixed with methyl ethyl ketone and the first working fluid, it is sprayed into the bottom of the reactor body 1 through the working fluid ejector 6 and is completely back-mixed with the ammonia gas coming out of the annular gas distributor 7 to ensure the ammonia concentration in the reaction system. Refer to Figure 4 , at the bottom of the reactor body 1 is the main reaction zone 11, where the synthesis reaction proceeds rapidly. The butanone hydrazone produced by the reaction is insoluble in water, and the product butanone hydrazone floats up and separates from the aqueous phase after dissolving methyl ethyl ketone. The product floats up into the secondary reaction zone 12 in the reactor body 1. Under the action of the turbine stirrer 3, the oil and water phases are mixed radially, and under the action of gravity and air flotation, the oil and water phases flow upward in a staggered manner. As the reaction proceeds, the liquid level in the reactor continues to rise, and the oil phase gradually floats up and separates from the aqueous phase and enters the overflow zone 13. The oil-phase product in the upper part of the liquid level overflows from the overflow port 8 at the top of the reactor in a timely manner and enters the oil-gas-water three-phase separator 9 for separation and collection. Respectively detect the butanone hydrazone content in the oil phase and the aqueous phase, and calculate the yield to be 89.7%.

[0030] During the above reaction process, control the reaction temperature at 50 - 55 °C.

[0031] In summary, this method utilizes the characteristic that the product butanone hydrazone is insoluble in the aqueous phase system, realizes the continuous synthesis of the product and the stable separation of the oil-phase product and the aqueous-phase working fluid, shortens the synthesis reaction time, and improves the production efficiency. The butanone hydrazone generated during the reaction process can be separated and removed from the reaction solution in a timely manner, thus effectively preventing the product from being oxidized by hydrogen peroxide, reducing the oxidation by-products, and increasing the yield of butanone hydrazone.

[0032] The above is only the schematic specific implementation manner of the present invention and is not used to limit the scope of the present invention. For example, baffles can be installed in the reactor body 1 or spiral nozzles can be installed at the gas distribution holes, etc. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for continuously synthesizing outer-loop heterogeneous butanone hydrazone, characterized in that, It includes the following steps: S1. Prepare a first working solution by mixing a catalyst and water; S2. Dissolve a promoter and a stabilizer in a hydrogen peroxide solution to form a second working solution; S3. Mix methyl ethyl ketone, the first working solution, and the second working solution and continuously feed them into a circulation reactor. Start stirring and the circulation pump to keep the mixed working solution in circulation. Continuously introduce ammonia gas into the mixed working solution in the circulation reactor, control the reaction temperature at 40 - 55 °C. The butanone hydrazone produced by the reaction is insoluble in water. After the product butanone hydrazone dissolves methyl ethyl ketone, an oil phase is formed. Under the action of gravity and air flotation, the oil and water phases flow upward in a staggered manner. As the reaction proceeds, the liquid level in the circulation reactor continuously rises, the oil phase floats and separates from the water phase, and the oil phase product overflows from the reaction system in a timely manner. The product is separated and collected.

2. The method for continuously synthesizing outer-loop heterogeneous methyl ethyl ketone azine as claimed in claim 1, characterized in that: In step S1, the catalyst is an amide and its corresponding carboxylate salt.

3. The heterogeneous continuous synthesis method with external circulation of butanone hydrazone as described in claim 2, wherein: In step S1, the catalyst is formamide and ammonium formate.

4. The heterogeneous continuous synthesis method with external circulation of butanone hydrazone as claimed in claim 2, characterized in that: In step S1, the catalyst is acetamide and ammonium acetate.

5. The heterogeneous continuous synthesis method of methyl ethyl ketone hydrazone with external circulation as claimed in claim 1, wherein: In step S2, the promoter is disodium hydrogen phosphate.

6. The heterogeneous continuous synthesis method with external circulation of butanone hydrazone as claimed in claim 1, characterized in that: In step S2, the stabilizer is disodium ethylenediaminetetraacetate.

7. The heterogeneous continuous synthesis method with external circulation for hydrazoisobutyronitrile according to claim 1, wherein: In step S2, the concentration of the hydrogen peroxide solution is 25 - 70 wt%.

8. The heterogeneous continuous synthesis method with external circulation of butanone hydrazone as claimed in claim 1, wherein: In step S2, the mass ratio of the promoter to the hydrogen peroxide solution is 0.1 - 2%; the mass ratio of the stabilizer to the hydrogen peroxide solution is 0.1 - 2%.

9. The heterogeneous continuous synthesis method with external circulation of butanone hydrazone as claimed in claim 1, characterized in that: In step S3, during the reaction process, control the molar ratio of methyl ethyl ketone to the hydrogen peroxide solution to be 1 - 5:1; the molar ratio of ammonia to the hydrogen peroxide solution to be 1 - 10:1; the molar ratio of the catalyst to the hydrogen peroxide solution to be 1 - 5:

1.

10. The outer-loop heterogeneous continuous synthesis method of butanone hydrazone according to any one of claims 1 to 9, characterized in that: The stirring in the circulation reactor uses a turbine stirrer with a rotation speed of 500 - 1000 rpm.

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