Continuous flow amination method of alkylcarboxylic acid-based compound

Abstract

To provide a continuous flow amination method of an alkylcarboxylic acid-based compound lower in cost, with a smaller amount of industrial waste, small in a volume of a reactor, high in safety, and stable in product quality.SOLUTION: A substituted alkylcarboxylic acid is used as a raw material. Firstly, an amination reagent and a catalyst are mixed in a micromixer, and preheated, thereafter mixed with a substituted alkylcarboxylic acid solution by a micromixer, and thereafter introduced to a dynamic continuous reactor to generate an organic amine product including a carboxylic group. A solid-containing liquid of a reaction liquid after passing through a gas-liquid separator is introduced to a multifunctional agitation vessel, and filtered twice to obtain a filtrate and a filtered cake, and the filtered cake is dried to obtain a high purity product. A first filtrate is concentrated by an inline evaporator to obtain a catalyst solution which is recovered and reused. After mixing a second filtrate and ammonia by a micromixer, the mixture is introduced to the reactor to react sufficiently, a filtrate obtained by filtration is recovered and reused as an alkali solution, and the filtered cake is an ammonium salt as a coproduct.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention belongs to the technical field of organic chemical synthesis, and specifically relates to a continuous flow amination method for alkylcarboxylic acid compounds. [Background technology]

[0002] The Delepine and Gabriel reactions are commonly used to produce primary amines. While the reaction conditions are mild and the product purity is high, the cost of reactants is poor and large amounts of chemical waste are generated, making their industrial application difficult. For example, the Delepine reaction uses urotropine as the aminating reagent, and only one of the four nitrogen atoms in urotropine can be utilized; the remaining nitrogen atoms are discharged as waste and are difficult to reuse. The Gabriel reaction uses phthalimide as the ammonia source, and the by-product phthalic acid is also difficult to reuse. Therefore, the development of catalytic amination reaction systems is crucial, as it can solve the challenges of the large reagent consumption and serious pollution in the production of primary amine compounds.

[0003] Patent CN105037186A uses a catalyst to achieve the aminolysis reaction and reuses the ammonia source, but does not recover the catalyst and does not disclose purification of the amination product. Furthermore, the reaction is performed using a traditional kettle-type process, resulting in low production efficiency and a long reaction time. Patent CN102241600A discloses a similar catalytic aminolysis reaction, but does not disclose recovery of the catalyst or ammonia source. Purification of the product requires the addition of water to utilize different solubilities, resulting in a large amount of product dissolving in water, reducing yields, and generating large amounts of wastewater containing organic matter, causing serious pollution and making it unsuitable for industrial applications. Patent CN102816077A also uses water as a solvent, resulting in a large amount of product dissolving in water, reducing yields, and generating large amounts of wastewater containing organic matter, causing serious pollution and making it unsuitable for industrial applications.

[0004] Therefore, it is urgent to develop a new amination reaction process that is economical in terms of reactant atoms, causes little pollution, allows catalyst recycling, and achieves a high product separation yield, thereby resolving the problems of conventional kettle-type production, such as poor continuity, difficulty in expanding production volume, and low production efficiency. Summary of the Invention

[0005] To overcome the drawbacks of the prior art, such as a long reaction time for the amination of alkylcarboxylic acids, low separation yield, inability to recycle catalysts, large amounts of waste (exhaust gas, wastewater, and solid waste), high energy consumption, and low product quality, the present invention provides a continuous flow method for the amination of alkylcarboxylic acid compounds.

[0006] In the continuous flow amination method for alkylcarboxylic acid compounds provided by the present invention, a highly purified alkylcarboxylic acid compound can be obtained by preparing the raw materials, starting from an aminating reagent (I) and a substituted alkylcarboxylic acid solution (II), using a fully continuous system consisting of a plurality of micromixers, microchannel reactors, and in-line purification devices, all of which are connected in series. The reaction equation is: [ka] and includes the following steps (1) to (3): (1) The aminating reagent (I) and the catalyst solution are thoroughly mixed in the first micro-mixer 1, then introduced into the first preheater 1 for preheating, and then introduced into the second micro-mixer 2 together with the preheated substituted alkylcarboxylic acid solution (II) for thorough mixing, and then introduced into a dynamic continuous reactor (a micro-channel reactor with a special structure) to produce the target product, a carboxyl-containing organic amine product (III). The reaction pressure is controlled by introducing nitrogen gas into the gas-liquid separator and a backpressure valve installed in the gas-liquid separator. After the reaction liquid passes through the gas-liquid separator, the solid-containing liquid enters the first multi-function stirring vessel 1 with a filtration function and is filtered to obtain a first filtrate and a first filter cake. The first filtrate is controlled by the three-way valve 2 to enter the first storage tank 1. The first filter cake and the alkaline solution are mixed, stirred, and dispersed, and then filtered again to obtain a second filtrate and a second filter cake. The second filtrate is controlled by the three-way valve to enter the second storage tank 2. The second filter cake is dried to obtain a high-purity product. (2) The first filtrate obtained in step (1) is pumped into a second preheater 2, and after preheating, is introduced into an in-line evaporator for concentration, while a nitrogen flow is used to promote solvent removal. The nitrogen flow rate is accurately controlled using a flow meter so that the concentration of the resulting catalyst solution matches the concentration at the time of initial use, thereby directly achieving recovery and reuse. The evaporated solvent is introduced into a condenser for condensation, and then introduced into a first collection tank 1 for recovery and reuse. (3) The second filtrate obtained in step (1) is pumped into the third micro-mixer 3, mixed with ammonia, and then introduced into the microchannel reactor for reaction. The reaction solution is introduced into the second multi-function stirring vessel 2 with filtration function. The filtrate obtained after filtration is an alkaline solution, which is introduced into the third storage tank 3 for recycling, and the filter cake is the co-product ammonium salt.

[0007] Preferably, in step (1), the aminating reagent is selected from ammonia gas, liquid ammonia, methylamine, ethylamine, and benzylamine, and the alkylcarboxylic acid is selected from fluoroacetic acid, chloroacetic acid, bromoacetic acid, and iodoacetic acid.

[0008] Preferably, in step (1), the aminating reagent is solvent-free or dissolved in methanol, the catalyst is dissolved in one of methanol, ethanol, isopropanol, and acetone, and the substituted alkyl carboxylic acid is dissolved in one of methanol, ethanol, and acetone.

[0009] Preferably, in step (1), the catalyst is selected from amantadine and urotropine.

[0010] Preferably, in step (1), the amount of the aminating reagent used is 1.2-3.5 equivalents of the substituted alkyl carboxylic acid, the concentration of the aminating reagent is 90-99%, and the amount of the catalyst used is 0.05-0.45 equivalents, more preferably 0.1-0.40 equivalents.

[0011] Preferably, in step (1), the preheater temperature is 30-50°C, the preheating time is 3-5 min, the reaction temperature of the dynamic continuous reactor is 70-100°C, the back pressure is 5-15 bar, and the reaction time is 10-180 min. More preferably, the reaction time is 20-150 min.

[0012] Preferably, in step (1), the first filter cake and the alkaline solution are mixed, stirred, and dispersed at a temperature of 55-110°C for 30-150 minutes, more preferably at a temperature of 55-80°C for 30-120 minutes.

[0013] Preferably, in step (1), the alkali in the alkaline solution is one or a combination of methylamine, ethylamine, butylamine, trimethylamine, triethylamine, tributylamine, N,N-diisopropylethylamine, pyridine, and p-dimethylaminopyridine, and the amount used is 1.5-4.0 equivalents of the substituted alkyl carboxylic acid.

[0014] Preferably, in step (2), the temperature of the preheater is 30-120°C, the in-line evaporator has a heat exchange jacket, the temperature of the heat exchange fluid is 45-100°C, and matches the preheater, and the ratio of the nitrogen flow rate to the first filtrate flow rate is 3:1-15:1.

[0015] Preferably, in step (3), the reaction temperature of the reactor is 30-50°C, the pressure is 1-5 bar, and the reaction time is 2-20 min. More preferably, the reaction time is 5-15 min.

[0016] In steps (1) and (3), the micromixer is a micromixer with a plate-type structure, with an inner diameter of 0.6 to 4.5 mm and a length of 2.5 to 45 m. In step (1), the dynamic continuous reactor is a horizontal or vertical multi-stage rotary agitation reactor with a heat exchange jacket, specifically a cylindrical cavity, the wall of which is a heat exchange fluid intervening layer, a central shaft provided within the cylindrical cavity, a plurality of agitation blades connected to the central shaft for enhancing mass transfer and heat transfer, the central shaft being driven by a motor and having a rotation speed of 50-500 rpm / min, a reactant inlet and a reactant outlet at both ends of the reactor cavity, respectively, a fluid heat inlet and a fluid heat outlet at both ends of the heat exchange fluid intervening layer, respectively, the inner diameter of the cylindrical cavity is 10-300 mm, and the length is 2.5-30 m (Fig. 2).

[0017] In steps (1) and (2), the preheater is a tubular microchannel structure, with an inner diameter of 0.8 to 45 mm and a length of 5 to 1000 m.

[0018] Preferably, in steps (1) and (3), the material of the microchannel reactor is one or a combination of two or more of polytetrafluoroethylene, polyvinylidene fluoride, stainless steel, Hastelloy, zirconium, tantalum, nickel, silicon carbide, and glass.

[0019] Compared with the prior art, the present invention has the following advantages: (1) The micro-mixer significantly improves the mass transfer effect of multi-phase systems, accelerating the reaction rate while reducing the reactor volume. The microchannel reactor has excellent mass transfer, heat transfer, and continuous material mixing enhancement performance, which effectively shortens the reaction time, improves reaction efficiency and the flow rate per unit volume of the reactor, increases reaction safety, and significantly reduces the emissions of three wastes (exhaust gas, wastewater, and solid waste) and energy consumption. The time required to prepare the target product is reduced from 5-10 hours required for traditional batch reactions to just a few minutes.

[0020] (2) This method realizes the recycling of catalysts, reduces production costs, improves profits, and effectively reduces waste.

[0021] (3) By carrying out the amination reaction in a dynamic continuous reactor, sufficient stirring and excellent heat transfer effect can be achieved, improving the safety of the reaction process while reducing the amount of aminating reagent and energy consumption, making the reaction process more environmentally friendly.

[0022] (4) Continuous synthesis from raw materials to products is realized, the process is carried out continuously, with a high degree of automation, no external intervention is required along the way, time and space efficiency is high, the number of workers and labor intensity are greatly reduced, and production costs are significantly reduced.

[0023] (5) Continuous production of the product was achieved, with a conversion rate of over 99%, a yield of the target product of over 95%, and a purity of over 99.5%.

[0024] (6) By using microchannel reactors, industrial production of the synthesis method of the present invention can be easily realized through multichannel parallel scale-up or size-up strategies. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a flow chart of the reaction process of the present invention. [Figure 2]2 is a structural schematic diagram of a dynamic continuous reactor. In Fig. 2, 1 - heat exchange fluid outlet, 2 - heat exchange fluid intervening layer, 3 - coaxial multi-blade agitator, 4 - heat exchange fluid inlet, 5 - motor, 6 - bottom plate, 7 - support frame, 8 - reactant outlet, 9 - reactant inlet. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention will now be further described with reference to examples.

[0027] Example 1 Ammonia gas (10 sccm) was accurately measured using flowmeter 1 and introduced into Y-shaped micromixer 1 at a flow rate of 3.1 mL / min along with a methanol solution of urotropine (0.40 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into preheated reactor 1. The preheated reactor had an inner diameter of 5 mm, a length of 100 m, a reaction temperature of 35 °C, and a reaction time of 3 min. At the reaction outlet, ammonia gas was introduced into the Y-shaped micromixer at a flow rate of 1.1 mL / min along with a methanol solution of chloroacetic acid (1.0 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into the dynamic continuous reactor for amination. The dynamic continuous reactor had an inner diameter of 150 mm, a length of 2.0 m, a reaction temperature of 90 °C, and a reaction time of 40 min. The internal pressure of the reactor was adjusted to 8 atm using a backpressure valve. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into a multifunctional stirring vessel 1 having a filtering function and filtered to obtain a crude target product and a first filtrate.

[0028] The crude target product was introduced into a multi-function stirring vessel together with a methanol solution of triethylamine (1.0 equivalent) at a flow rate of 2.1 mL / min using a feed pump and stirred (temperature 65°C, time 80 min). After solid-liquid separation, the mixture was dried to obtain a high-purity product and a second filtrate. The yield of the target product was 95%, and the purity was 99.8%.

[0029] The first filtrate was mixed in Y-type mixer 2 with nitrogen gas, the flow rate of which was controlled at 50 sccm by flowmeter 2, at a flow rate of 4.0 mL / min using a feed pump, and the mixture was introduced into preheating reactor 2. The preheating reactor had an inner diameter of 5 mm and a length of 30 m, a reaction temperature of 75°C, a heat exchange fluid temperature of 85°C, and a reaction time of 5 min. Methanol was concentrated using an in-line evaporator with a heat exchange jacket, and the evaporated methanol was condensed using a condenser and collected in collection tank 1. The concentrated methanol solution of urotropine was introduced into the Y-type micromixer at a flow rate of 3.1 mL / min using a feed pump and mixed uniformly, and then introduced into preheating reactor 1 and used as a circulating catalyst.

[0030] The second filtrate was mixed in Y-type mixer 3 with ammonia gas (flow rate controlled at 10 sccm using flowmeter 2) at a flow rate of 2.1 mL / min using a feed pump, and then introduced into the microchannel reactor. The reactor reaction temperature was 30°C, the pressure was 1 bar, and the reaction time was 5 minutes. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into multi-function stirring vessel 2 with a filtration function and filtered, yielding a methanol solution of ammonium chloride nitrogen fertilizer and triethylamine. The methanol solution of triethylamine was introduced into multi-function stirring vessel 1 at a flow rate of 2.1 mL / min using a feed pump, and was recycled and purified for use.

[0031] Example 2 Ammonia gas (20 sccm) was accurately measured using flowmeter 1 and introduced into Y-shaped micromixer 1 at a flow rate of 5.1 mL / min along with a methanol solution of urotropine (0.30 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into preheated reactor 1. The preheated reactor had an inner diameter of 7 mm, a length of 200 m, a reaction temperature of 45 °C, and a reaction time of 3 min. At the reaction outlet, ammonia gas was introduced into the Y-shaped micromixer at a flow rate of 1.5 mL / min along with a methanol solution of chloroacetic acid (1.0 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into the dynamic continuous reactor for amination. The dynamic continuous reactor had an inner diameter of 200 mm, a length of 2.5 m, a reaction temperature of 70 °C, and a reaction time of 50 min. The internal pressure of the reactor was adjusted to 10 atm using a backpressure valve. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into a multifunctional stirring vessel 1 having a filtering function and filtered to obtain a crude target product and a first filtrate.

[0032] The crude target product was introduced into a multi-function stirring vessel together with a methanol solution of triethylamine (1.2 equivalents) at a flow rate of 4.0 mL / min using a feed pump and stirred (temperature 70 °C, time 70 min), followed by solid-liquid separation and drying to obtain a high-purity product and a second filtrate. The yield of the target product was 95%, and the purity was 99.5%.

[0033] The first filtrate was mixed in Y-type mixer 2 with nitrogen gas, the flow rate of which was controlled at 100 sccm by flowmeter 2, at a flow rate of 6.5 mL / min using a feed pump, and the mixture was introduced into preheating reactor 2. The preheating reactor had an inner diameter of 5 mm and a length of 25 m, a reaction temperature of 80°C, a heat exchange fluid temperature of 90°C, and a reaction time of 4 min. Methanol was concentrated using an in-line evaporator with a heat exchange jacket, and the evaporated methanol was condensed using a condenser and collected in collection tank 1. The concentrated methanol solution of urotropine was introduced into the Y-type micromixer at a flow rate of 5.1 mL / min using a feed pump and mixed uniformly, and then introduced into preheating reactor 1 and used as a circulating catalyst.

[0034] The second filtrate was mixed in Y-type mixer 3 with ammonia gas (flow rate controlled at 20 sccm using flowmeter 2) at a flow rate of 4.0 mL / min using a feed pump, and then introduced into the reactor. The reactor reaction temperature was 35°C, the pressure was 3 bar, and the reaction time was 5.5 min. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into multi-function stirring vessel 2 with a filtration function and filtered, yielding a methanol solution of ammonium chloride nitrogen fertilizer and triethylamine. The methanol solution of triethylamine was introduced into multi-function stirring vessel 1 at a flow rate of 4.0 mL / min using a feed pump, and was recycled and purified for use.

[0035] Example 3 Ammonia gas (30 sccm) was accurately measured using flowmeter 1 and introduced into Y-shaped micromixer 1 at a flow rate of 7.0 mL / min along with a methanol solution of urotropine (0.35 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into preheated reactor 1. The preheated reactor had an inner diameter of 5 mm, a length of 250 m, a reaction temperature of 55 °C, and a reaction time of 6.5 min. At the reaction outlet, ammonia gas was introduced into the Y-shaped micromixer at a flow rate of 3.2 mL / min along with a methanol solution of chloroacetic acid (1.8 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into the dynamic continuous reactor for amination. The dynamic continuous reactor had an inner diameter of 250 mm, a length of 3.0 m, a reaction temperature of 100 °C, and a reaction time of 50 min. The internal pressure of the reactor was adjusted to 9 atm using a backpressure valve. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into a multifunctional stirring vessel 1 having a filtering function and filtered to obtain a crude target product and a first filtrate.

[0036] The crude target product was introduced into a multi-function stirring vessel together with a methanol solution of triethylamine (1.2 equivalents) at a flow rate of 4.5 mL / min using a feed pump and stirred (temperature 70°C, time 90 min), followed by solid-liquid separation and drying to obtain a high-purity product and a second filtrate. The yield of the target product was 96%, and the purity was 99.7%.

[0037] The first filtrate was mixed in Y-type mixer 2 with nitrogen gas, the flow rate of which was controlled at 250 sccm by flowmeter 2, at a flow rate of 10 mL / min using a feed pump, and the mixture was introduced into preheating reactor 2. The preheating reactor had an inner diameter of 8 mm and a length of 50 m, a reaction temperature of 80°C, a heat exchange fluid temperature of 95°C, and a reaction time of 8 min. Methanol was concentrated using an in-line evaporator with a heat exchange jacket, and the evaporated methanol was condensed using a condenser and collected in collection tank 1. The concentrated methanol solution of urotropine was introduced into the Y-type micromixer at a flow rate of 7.0 mL / min using a feed pump and mixed uniformly, and then introduced into preheating reactor 1 and used as a circulating catalyst.

[0038] The second filtrate was mixed in Y-type mixer 3 with ammonia gas (flow rate controlled at 40 sccm using flowmeter 2) at a flow rate of 4.5 mL / min using a feed pump, and then introduced into the reactor. The reactor reaction temperature was 35°C, the pressure was 5 bar, and the reaction time was 7 minutes. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into multi-function stirring vessel 2 with a filtration function and filtered, yielding a methanol solution of ammonium chloride nitrogen fertilizer and triethylamine. The methanol solution of triethylamine was introduced into multi-function stirring vessel 1 at a flow rate of 4.5 mL / min using a feed pump, and was recycled and purified for use.

[0039] Example 4 Ammonia gas (50 sccm) was accurately measured using flowmeter 1 and introduced into Y-shaped micromixer 1 at a flow rate of 12.0 mL / min along with a methanol solution of urotropine (0.25 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into preheated reactor 1. The preheated reactor had an inner diameter of 10 mm, a length of 350 m, a reaction temperature of 40 °C, and a reaction time of 5 min. At the reaction outlet, ammonia gas was introduced into the Y-shaped micromixer at a flow rate of 4.0 mL / min along with a methanol solution of chloroacetic acid (2.0 equivalents) using a feed pump. After uniform mixing, the mixture was introduced into the dynamic continuous reactor for amination. The dynamic continuous reactor had an inner diameter of 300 mm, a length of 3.0 m, a reaction temperature of 110 °C, and a reaction time of 60 min. The internal pressure of the reactor was adjusted to 10 atm using a backpressure valve. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into a multifunctional stirring vessel 1 having a filtering function and filtered to obtain a crude target product and a first filtrate.

[0040] The crude target product was introduced into a multi-function stirring vessel together with a methanol solution of triethylamine (1.0 equivalent) at a flow rate of 6.0 mL / min using a feed pump and stirred (temperature 70 °C, time 85 min), followed by solid-liquid separation and drying to obtain a high-purity product and a second filtrate. The yield of the target product was 95%, and the purity was 99.7%.

[0041] The first filtrate was mixed in Y-type mixer 2 with nitrogen gas, the flow rate of which was controlled at 100 ccm by flow meter 2, at a flow rate of 15.5 mL / min using a feed pump, and the mixture was introduced into preheating reactor 2. The preheating reactor had an inner diameter of 8 mm and a length of 55 m, a reaction temperature of 85°C, a heat exchange fluid temperature of 90°C, and a reaction time of 5 min. Methanol was concentrated using an in-line evaporator with a heat exchange jacket, and the evaporated methanol was condensed using a condenser and collected in collection tank 1. The concentrated methanol solution of urotropine was introduced into the Y-type micromixer at a flow rate of 12.0 mL / min using a feed pump and mixed uniformly, and then introduced into preheating reactor 1 and used as a circulating catalyst.

[0042] The second filtrate was mixed in Y-type mixer 3 with ammonia gas (flow rate controlled at 50 sccm using flowmeter 2) at a flow rate of 6.0 mL / min using a feed pump, and then introduced into the reactor. The reactor reaction temperature was 35°C, the pressure was 5 bar, and the reaction time was 8 minutes. After the reaction liquid passed through the gas-liquid separator, the solid-containing liquid was introduced into multi-function stirring vessel 2 with a filtration function and filtered, yielding a methanol solution of ammonium chloride nitrogen fertilizer and triethylamine. The methanol solution of triethylamine was introduced into multi-function stirring vessel 1 at a flow rate of 6.0 L / min using a feed pump, purified, and used after circulation.

[0043] It should be noted that the above embodiments do not limit the present invention, and any changes and modifications to the above embodiments, or any conversion of equivalent structures or processes based on the contents of the specification and drawings of the present invention, are all included within the protection scope of the present invention.

Claims

1. A continuous flow amination method for alkylcarboxylic acid compounds, in which a high-purity alkylcarboxylic acid compound is obtained by preparing the alkylcarboxylic acid compound using an aminating reagent (I) and a substituted alkylcarboxylic acid solution (II) as raw materials in a completely continuous system comprising a plurality of micromixers, microchannel reactors and an in-line purification device, which are sequentially connected to each other, comprising: The reaction equation is: 【Chemistry 1】 and includes the following steps (1) to (3): (1) The aminating reagent (I) and the catalyst solution are thoroughly mixed in a first micro-mixer, then introduced into a first preheater for preheating, and then introduced into a second micro-mixer together with the substituted alkylcarboxylic acid solution (II) for thorough mixing, and then introduced into a dynamic continuous reactor to produce the target product, a carboxyl-containing organic amine product (III). The reaction pressure is controlled by introducing nitrogen gas into a gas-liquid separator and a backpressure valve installed in the gas-liquid separator. The reaction liquid passes through the gas-liquid separator and is separated. The solid-containing liquid enters a first multi-function stirring vessel with a filtration function and is filtered to obtain a first filtrate and a first filter cake. The first filtrate is controlled by a three-way valve to enter a first storage tank. The first filter cake and the alkaline solution are mixed, stirred, and dispersed, and then filtered again to obtain a second filtrate and a second filter cake. The second filtrate is controlled by a three-way valve to enter a second storage tank. The second filter cake is dried to obtain a high-purity product. (2) The first filtrate obtained in step (1) is pumped into a second preheater, and after preheating, is introduced into an in-line evaporator for concentration, while a nitrogen flow is used to promote the removal of the solvent. The nitrogen flow rate is precisely controlled using a flow meter to ensure that the concentration of the resulting catalyst solution is consistent with the concentration at the time of initial use, thereby directly achieving recovery and reuse; the evaporated solvent is introduced into a condenser for condensation, and then introduced into a first collection tank for recovery and reuse; (3) The second filtrate obtained in step (1) is introduced into a third micro-mixer by a pump, mixed with ammonia, and then introduced into a micro-channel reactor for reaction; the reaction liquid is introduced into a second multi-function stirring vessel with filtration function; the filtrate obtained after filtration is an alkaline solution, which is introduced into a third storage tank for recovery and reuse; and the filter cake is the co-product ammonium salt.

2. In step (1), the aminating reagent is selected from ammonia gas, liquid ammonia, methylamine, ethylamine, and benzylamine, and the alkylcarboxylic acid is selected from fluoroacetic acid, chloroacetic acid, bromoacetic acid, and iodoacetic acid, and the aminating reagent is solventless or dissolved in methanol; 2. The method according to claim 1, wherein the catalyst is selected from amantadine and urotropine, the solvent of the catalyst solution is one selected from methanol, ethanol, isopropanol, and acetone, and the solvent of the substituted alkyl carboxylic acid solution is one selected from methanol, ethanol, and acetone.

3. 3. The method of claim 2, wherein in step (1), the amount of aminating reagent used is 1.2-3.5 equivalents of the substituted alkyl carboxylic acid, the concentration of the aminating reagent is 90-99%, the amount of catalyst used is 0.05-0.45 equivalents, and the alkali of the alkaline solution is selected from methylamine, ethylamine, butylamine, trimethylamine, triethylamine, tributylamine, N,N-diisopropylethylamine, pyridine, and p-dimethylaminopyridine, and the amount used is 1.5-4.0 equivalents of the substituted alkyl carboxylic acid.

4. 2. The method of claim 1, wherein in step (1), the temperature of the preheater is 30-50°C, the preheating time is 3-5 min, the reaction temperature of the dynamic continuous reactor is 70-100°C, the back pressure is 5-15 bar, and the reaction time is 10-180 min.

5. 2. The method according to claim 1, wherein in step (1), the temperature during mixing, stirring and dispersing the first filter cake and the alkaline solution is 55-110°C, and the time is 30-150 min.

6. 2. The method of claim 1, wherein in step (2), the temperature of the preheater is 30-120°C, the in-line evaporator has a heat exchange jacket, the temperature of the heat exchange fluid is 45-100°C, and coincides with the preheater, and the ratio of the nitrogen flow rate to the first filtrate flow rate is 3:1-15:

1.

7. 2. The method according to claim 1, wherein in step (3), the reaction temperature of the reactor is 30-50°C, the pressure is 1-5 bar, and the reaction time is 2-20 min.

8. 2. The method of claim 1, wherein in steps (1) and (3), the micro-mixer is a plate-type micro-mixer, with an inner diameter of 0.6-4.5 mm and a length of 2.5-45 m.

9. 10. The method of claim 1, wherein in step (1), the dynamic continuous reactor is a horizontal or vertical multi-stage rotary stirring reactor with a heat exchange jacket, specifically a cylindrical cavity, the wall of the cylindrical cavity being a heat exchange fluid intervening layer, a central shaft is provided within the cylindrical cavity, a plurality of stirring blades are connected to the central shaft to enhance mass transfer and heat transfer, the central shaft is driven by a motor and the rotation speed is 50-500 rpm / min, a reactant inlet and a reactant outlet are provided at both ends of the reactor cavity, respectively, a fluid heat inlet and a fluid heat outlet are provided at both ends of the heat exchange fluid intervening layer, respectively, the inner diameter of the cylindrical cavity is 10-300 mm, and the length is 2.5-30 m.

10. 2. The method according to claim 1, wherein in steps (1) and (2), the preheater is a tubular microchannel structure, with an inner diameter of 0.8-45 mm and a length of 5-1000 m.

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