Continuous reaction equipment of N-n-butyl thiophosphoric triamide and preparation method of N-n-butyl thiophosphoric triamide

Abstract

The invention relates to continuous reaction equipment of N-n-butyl thiophosphoric triamide and a preparation method of the N-n-butyl thiophosphoric triamide. The invention discloses a continuous preparation method of N-n-butyl thiophosphoric triamide and reaction equipment, and belongs to the technical field of fine chemical engineering. The method comprises the following steps: uniformly mixing thiophosphoryl chloride serving as an initial raw material with a solvent in a batching kettle to prepare a thiophosphoryl chloride solution; the method comprises the following steps: respectively adding a thiophosphoryl chloride solution, n-butylamine and inert gas into a micro-channel reactor through a flow pump to carry out substitution reaction, and separating hydrogen chloride gas and an N-n-butyl dichlorothiophosphoramide solution through a gas-liquid separator; then adding the N-n-butyl dichlorophosphoramide thiophosphate solution and liquid ammonia into a tubular reactor through a flow pump to obtain an N-n-butyl thiophosphoric triamide solution; and finally, extracting, washing, concentrating an organic phase, crystallizing, separating and drying to obtain the high-purity N-n-butyl thiophosphoric triamide. The method is safe, efficient, simple and convenient to operate, good in reaction selectivity, high in yield, low in pollutant emission, low in production cost and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to a method and reaction equipment for preparing N-n-butylthiophosphoric triamine by combining microchannels and pipelines, belonging to the field of fine chemical technology. Background Technology

[0002] N-Butylthiophosphoric triamine is one of the most effective soil urease inhibitors currently available. It has outstanding advantages such as high efficiency, non-toxicity, and no side effects, and is usually used as an active ingredient in compound fertilizers.

[0003] CN101337976A reports a method for producing N-n-butylthiophosphoric triamine. The method involves reacting trichlorophosphorus with n-butylamine and separating the intermediate N-n-butyldichlorothiophosphoramide. The purified N-n-butyldichlorothiophosphoramide is then reacted with ammonia gas, followed by further treatment to obtain N-n-butylthiophosphoric triamine. This process is relatively cumbersome, involves both high and low temperature reaction requirements, has poor reaction selectivity, a long production cycle, and high costs, thus lacking commercial viability.

[0004] CN101412733A reports a one-pot synthesis method for preparing N-n-butylthiophosphoric triamine. The reaction uses triethylamine as a base, and the reaction time for the final ammonia gas introduction is relatively long (usually requiring 2 hours), which increases the production cost. Furthermore, the use of triethylamine and a large amount of ammonia poses a significant environmental hazard.

[0005] CN102030775B reports a pipeline-based method for the synthesis of N-n-butylthiophosphoric triamine. However, the tubular reaction is only applied to the first step of the reaction. The second step still uses a traditional batch reactor and also has a long reaction time for ammonia gas (usually 2.5-3 hours). The production cost is high, and the problems of production cost control and potential environmental hazards have not been solved.

[0006] CN102746333B reports a method for preparing N-n-butylthiophosphoric triamine using an inorganic base as an acid-binding agent. However, it requires the simultaneous addition of n-butylamine and an aqueous solution of the inorganic base, which places extremely high demands on the control of the dropping rate and is not suitable for industrial production.

[0007] CN110950904B reports a continuous preparation method for N-n-butylthiophosphoric triamine using a microchannel and tubular reaction apparatus. Although a continuous method is adopted, the hydrogen chloride generated in the key step one reaction is always present in the continuous reaction process, and the removal of a large amount of gas depends on the ion exchange resin device, which has low efficiency.

[0008] Therefore, if we can further improve the heat transfer, mass transfer and separation effects through engineering and technical means on the basis of the already relatively mature process route, overcome the selectivity problem caused by high reactivity, and realize the continuous production of N-n-butylthiophosphoric triamine, it will be of great benefit to improving the raw material conversion efficiency and the overall competitiveness of the product.

[0009] To address the problems of traditional processes, this technology is based on a continuous flow method, using trichlorophosphorus, n-butylamine, and ammonia as raw materials. Through microchannel reaction and tubular reaction device in solution, it realizes the continuous production of N-n-butylthiophosphoric triamine, overcomes the shortcomings of existing technologies, further simplifies the process, improves reaction selectivity and yield, and achieves the goals of clean production, improved efficiency, shortened production cycle, and reduced production costs. Summary of the Invention

[0010] To overcome the aforementioned technical deficiencies, this invention provides a continuous flow technology and apparatus that integrates microchannel and tubular reactions, enabling the continuous preparation of N-n-butylthiophosphoric triamine in both microreactors and tubular reactors. This method is safe, efficient, simple to operate, exhibits good reaction selectivity, high yield, low pollutant emissions, and low production costs, making it suitable for industrial production.

[0011] This invention provides a continuous preparation apparatus for N-n-butylthiophosphoric triamine, comprising a batching tank, a microchannel reactor, a gas-liquid separator, a metering pump, a flow pump, and a tubular reactor.

[0012] A batching vessel with a feeding pipe fixedly connected to the top; The microchannel reactor is connected to the discharge port of the mixing vessel via a first connecting pipe; The gas-liquid separator is connected to the outlet of the microchannel reactor via a third connecting pipe; A liquid outlet pipe is fixedly connected to the bottom of the gas-liquid separator; a second flow pump is fixedly connected to the end of the liquid outlet pipe away from the gas-liquid separator. A tubular reactor is connected to the second flow pump via a fourth connecting pipe; A liquid ammonia feeding pipe is fixedly connected to the second flow pump; A first flow pump is fixedly connected to the tail end of the first connecting pipe; a n-butylamine feeding pipe and a nitrogen feeding pipe are fixedly connected to the first flow pump respectively; A second connecting pipe is also fixedly connected to the output end of the first flow pump, and the second connecting pipe is connected to the microchannel reactor.

[0013] Preferably, an outlet pipe is fixedly connected to the top side wall of the gas-liquid separator.

[0014] The present invention also provides a continuous preparation method of N-n-butylthiophosphoric triamine using the above-mentioned equipment, comprising the following steps: (1) Trichlorophosphorus is used as the starting material. After being mixed evenly with solvent in a mixing tank, a trichlorophosphorus solution is prepared. The trichlorophosphorus solution, n-butylamine and inert gas are added to the microchannel reactor through the first connecting pipe, the n-butylamine feeding pipe and the nitrogen feeding pipe respectively to carry out the substitution reaction. The hydrogen chloride gas is separated by the gas-liquid separator to obtain N-n-butyldichlorothiophosphoramide solution. (2) The N-n-butyldichlorothiophosphoramide solution and liquid ammonia were added to the tubular reactor through the outlet pipe and the liquid ammonia feeding pipe via the second flow pump to obtain the N-n-butyldichlorothiophosphoramide solution. (3) The N-n-butylthiophosphoric triamine solution was extracted and washed, the organic phase was concentrated and then crystallized, separated and dried to obtain high-purity N-n-butylthiophosphoric triamine.

[0015] In step (1), the concentration of the trichlorophosphorus solution is 5%~50%, preferably 10~15%; the molar ratio of trichlorophosphorus, n-butylamine and inert gas is 1:0.8~1.2:0.5~1.5, preferably 1:0.9~1.1:0.7~1.0. The reaction temperature is 0~60℃, preferably 15~35℃.

[0016] In step (1), the solvent is selected from toluene, dichloromethane, dichloroethane, chlorobenzene, anisole, isopropyl acetate, 2-methyltetrahydrofuran, etc., preferably from toluene, dichloromethane, and dichloroethane.

[0017] In step (1), the flow rate of the trichlorophosphorus solution is 20~500 g / min, preferably 50~300 g / min; the flow rate of n-butylamine is 2~50 g / min, preferably 8~30 g / min; and the flow rate of nitrogen is 0.5~50 g / min, preferably 2.5~15 g / min.

[0018] In step (1), the microchannel reaction residence time is 20-600 seconds, preferably 30-100 seconds; In step (1), the inert gas is selected from nitrogen, argon, etc.; the inert gas can help disperse the hydrogen chloride gas generated in the reaction and reduce the probability of salt formation with n-butylamine.

[0019] In step (1), the gas-liquid separator can effectively separate the acidic mixed gas diluted with nitrogen generated by the reaction from the reaction liquid portion, and the gas portion is connected to the absorption device.

[0020] In step (2), the molar ratio of N-n-butyldichlorothiophosphoramide to liquid ammonia is 1:2~100, preferably 1:2.5~5.5; the reaction temperature is 0~50℃, preferably 10~30℃.

[0021] In step (2), the flow rate of the N-n-butyldichlorothiophosphoramide solution is 20~600 g / min, preferably 60~350 g / min; the flow rate of liquid ammonia is 2~60 g / min, preferably 6~30 g / min.

[0022] In step (2), the inner diameter of the pipeline reactor is 5-200 mm, preferably 10-80 mm; the reaction residence time is 5-60 minutes, preferably 10-25 minutes.

[0023] In step (2), the length of the pipeline reactor is 1 to 500 meters, preferably 50 to 300 meters.

[0024] In step (3), the post-processing is as follows: after the reaction is completed, water is added to quench the reaction, the layers are extracted and separated, and the organic phase is concentrated and crystallized to obtain the product n-butylthiophosphoric triamine; the aqueous phase is treated to recover the by-product ammonium chloride.

[0025] Compared with the prior art, the advantages of the present invention are as follows: (1) This invention achieves continuous production by connecting a microchannel reactor and a tubular reactor in series with a gas-liquid separation device and performing two ammoniation reaction steps in series, simplifying the production process and improving production efficiency. By utilizing the efficient heat and mass transfer characteristics of the microchannel reactor, the heat released in the substitution reaction can be quickly dispersed, avoiding side reactions caused by excessively high local temperatures and improving reaction selectivity. At the same time, the precise control of the feeding ratio and flow rate of trichlorophosphoric acid solution, n-butylamine and nitrogen by the first flow pump further ensures the stability of the substitution reaction and ensures the efficient generation of the intermediate N-n-butyldichlorothiophosphoramide.

[0026] (2) The two reaction steps in the preparation method of this invention have large and concentrated heat release. By rationally connecting the batching tank, microchannel reactor, gas-liquid separator, tubular reactor and various connecting pipes and flow pumps, the raw material batching, substitution reaction, gas-liquid separation, secondary reaction and material transportation are integrated into a continuous process. This eliminates the cumbersome steps of intermittent reaction and step-by-step separation in traditional processes, significantly shortens the production cycle, increases the product output per unit time, and meets the needs of large-scale industrial production. The total reaction yield can reach more than 90%, and the product purity is more than 98%.

[0027] (3) A gas-liquid separator is set up in the continuous process, which can quickly separate the hydrogen chloride gas generated by the replacement reaction and connect it to the absorption device for centralized treatment through the gas outlet pipe. This avoids the hydrogen chloride gas from causing equipment corrosion or affecting the reaction efficiency due to subsequent reactions. At the same time, there is no need to use acid binder, which reduces the generation of pollutants. In addition, the amount of each material is precisely controlled by the flow pump, which avoids excessive waste of raw materials such as ammonia and reduces the pressure of environmental protection treatment. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a continuous preparation device for N-n-butylthiophosphoric triamine proposed in this invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of a continuous preparation device for N-n-butylthiophosphoric triamine proposed in this invention. Figure 2 .

[0029] In the diagram: 1. Feeding pipe; 2. Batching vessel; 201. First connecting pipe; 3. n-Butylamine feeding pipe; 4. Nitrogen feeding pipe; 5. First flow pump; 501. Second connecting pipe; 6. Microchannel reactor; 601. Third connecting pipe; 7. Gas-liquid separator; 8. Gas outlet pipe; 9. Liquid outlet pipe; 10. Liquid ammonia feeding pipe; 11. Second flow pump; 1101. Fourth connecting pipe; 12. Tubular reactor. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto. Example 1

[0031] Reference Figures 1-2 A continuous preparation apparatus for N-n-butylthiophosphoric triamine, comprising: A batching vessel 2 with a feeding pipe 1 fixedly connected to its top; The microchannel reactor 6 is connected to the outlet of the batching vessel 2 via the first connecting pipe 201; The gas-liquid separator 7 is connected to the outlet of the microchannel reactor 6 via the third connecting pipe 601; The liquid outlet pipe 9 is fixedly connected to the bottom of the gas-liquid separator 7; a second flow pump 11 is fixedly connected to the end of the liquid outlet pipe 9 away from the gas-liquid separator 7. The tubular reactor 12 is connected to the second flow pump 11 via the fourth connecting pipe 1101; A liquid ammonia feeding pipe 10 is fixedly connected to the second flow pump 11; A first flow pump 5 is fixedly connected to the tail end of the first connecting pipe 201; a n-butylamine feeding pipe 3 and a nitrogen feeding pipe 4 are fixedly connected to the first flow pump 5 respectively. A second connecting pipe 501 is also fixedly connected to the output end of the first flow pump 5, and the second connecting pipe 501 is connected to the microchannel reactor 6.

[0032] An outlet pipe 8 is fixedly connected to the top side wall of the gas-liquid separator 7.

[0033] The length of the tubular reactor 12 is 1-500 meters.

[0034] Reference Figures 1-2 In practical use, the steps are as follows: Step 1: Preparation of ingredients: Add trichlorfon raw material and solvent into the mixing tank 2 through the feeding pipe 1 at the top of the mixing tank 2, stir and mix evenly to prepare a trichlorfon solution with a concentration of 5%~50%.

[0035] In practical implementation, solvents such as toluene, dichloromethane, and dichloroethane can be selected.

[0036] Step 2, Material Delivery and First Reaction Start-up: Start the first flow pump 5, and deliver the prepared trichlorophosphorus solution from the mixing vessel 2 to the first flow pump 5 through the first connecting pipe 201; simultaneously, deliver n-butylamine to the first flow pump 5 through the n-butylamine feeding pipe 3, and deliver nitrogen to the first flow pump 5 through the nitrogen feeding pipe 4, controlling the molar ratio of trichlorophosphorus, n-butylamine, and inert gas to be 1:0.8~1.2:0.5~1.5; adjust the material flow rate so that the flow rate of trichlorophosphorus solution is 20~500 g / min, the flow rate of n-butylamine is 2~50 g / min, and the flow rate of nitrogen is 0.5~50 g / min; after mixing, the material enters the microchannel reactor 6 through the second connecting pipe 501, controlling the reaction temperature in the microchannel reactor 6 to be 0~60℃, and the residence time of the material in the microchannel reactor 6 to be 20~600 seconds, to carry out the substitution reaction to generate N-n-butyldichlorothiophosphoramide, while simultaneously generating hydrogen chloride gas.

[0037] Step 3, gas-liquid separation: The reaction mixture in the microchannel reactor 6 is transported to the gas-liquid separator 7 through the third connecting pipe 601, where hydrogen chloride gas is separated from the reaction liquid phase; the separated hydrogen chloride gas is discharged through the gas outlet pipe 8 on the top side wall of the gas-liquid separator 7 and connected to the absorption device for treatment.

[0038] Step 4, Second Reaction Start-up: Start the second flow pump 11. The reaction liquid phase at the bottom of the gas-liquid separator 7 enters the second flow pump 11 through the liquid outlet pipe 9. Liquid ammonia is supplied to the second flow pump 11 through the liquid ammonia feeding pipe 10. The molar ratio of N-n-butyldichlorothiophosphoramide to liquid ammonia is controlled at 1:2~100. The flow rate of liquid ammonia is adjusted to 2~60g / min, and the flow rate of the reaction liquid phase is 20~600g / min. The mixed material enters the tubular reactor 12 through the fourth connecting pipe 1101. The reaction temperature in the tubular reactor 12 is controlled at 0~50℃, and the residence time of the material in the tubular reactor 12 is 5~60 minutes to produce N-n-butyldichlorothiophosphoramide.

[0039] Step 5, Post-processing of the product: The reaction liquid discharged from tubular reactor 12 is subsequently quenched with water, extracted and separated, concentrated and crystallized in the organic phase, separated and dried to obtain high-purity N-n-butylthiophosphoric triamine product. The aqueous phase is treated to recover the by-product ammonium chloride. Example 2

[0040] Under nitrogen protection, 100 kg (590.6 mol, 1 eq) of trichlorophosphine and 350 kg of toluene were added to the mixing reactor 2 via feed pipe 1 and mixed thoroughly to obtain a trichlorophosphine-toluene solution. The trichlorophosphine-toluene solution, 43.2 kg (590.6 mol, 1.0 eq) of n-butylamine, and 16.5 kg (590.6 mol, 1.0 eq) of nitrogen were pumped into the microchannel reactor 6 via pipe 501 through pipes 201, 3, and 4 via calibrated flow pump 5. The reactor temperature was set to 25℃, and the reaction retention time was 80 s. Specifically, the injection rates for the trichlorophosphine-toluene solution were 104.2 g / min (0.137 mol / min), the n-butylamine injection rate was 10 g / min (0.137 mol / min), and the nitrogen injection rate was 3.8 g / min (0.137 mol / min). The toluene solution in the reaction system at the outlet of reactor 6 is separated into two phases by gas-liquid separator 7. The gas phase is connected to the alkaline absorption device via outlet pipe 8, while the liquid phase is directly used for the next reaction. The obtained N-n-butyldichlorothiophosphoryltoluene solution and liquid ammonia are injected into tubular reactor 12 via calibrated flow pumps 11 through pipes 9 and 10, respectively. The injection rate of N-n-butyldichlorothiophosphoryltoluene solution is 109.2 g / min, and the injection rate of liquid ammonia is 10.5 g / min. They enter the tubular reactor with an inner diameter of 20 mm. The reactor temperature is set at 20℃, and the reaction residence time is 15 minutes. After the reaction is completed, water is added directly, stirred, and allowed to stand for layering. The aqueous phase is extracted twice with toluene. After combining the extracts, the organic phase is distilled under reduced pressure to recover about 80%. The residue is cooled and crystallized to obtain the product n-butylthiophosphoryltriamine solid. After drying, 89.8 kg of white solid is obtained, with a yield of 90.9% and a purity of 98.9%. Example 3

[0041] Under nitrogen protection, 100 kg (590.6 mol, 1 eq) of trichlorophosphine and 400 kg of toluene were added to the mixing reactor 2 via feed pipe 1 and mixed thoroughly to obtain a trichlorophosphine-toluene solution. The trichlorophosphine-toluene solution, 43.2 kg (590.6 mol, 1.0 eq) of n-butylamine, and 16.5 kg (590.6 mol, 1.0 eq) of nitrogen were pumped into the microchannel reactor 6 via pipe 501 through pipes 201, 3, and 4 via a calibrated flow pump 5. The reactor temperature was set to 25℃, and the reaction retention time was 100 s. The injection rates were: trichlorophosphine-toluene solution 224.7 g / min, n-butylamine 20 g / min, and nitrogen 9.2 g / min. The toluene solution in the reaction system at the outlet of reactor 6 is separated into two phases by gas-liquid separator 7. The gas phase is connected to the alkaline absorption device via outlet pipe 8, while the liquid phase is directly used for the next reaction. The obtained N-n-butyldichlorothiophosphoryltoluene solution and liquid ammonia are injected into tubular reactor 12 through calibrated flow pumps 11 via pipes 9 and 10, respectively. The injection rate of N-n-butyldichlorothiophosphoryltoluene solution is 132.59 g / min, and the injection rate of liquid ammonia is 10.7 g / min. They enter the tubular reactor with an inner diameter of 20 mm. The reactor temperature is set to 20 °C, and the reaction residence time is 15 minutes. After the reaction is completed, water is added directly, stirred, and allowed to stand for layering. The aqueous phase is extracted twice with toluene. After combining the extracts, the organic phase is distilled under reduced pressure to recover about 80%. The residue is cooled and crystallized to obtain the product n-butylthiophosphoryltriamine solid. After drying, 92.7 kg of white solid is obtained, with a yield of 93.2% and a purity of 99.2%. Example 4

[0042] Under nitrogen protection, 100 kg (590.6 mol, 1 eq) of trichlorophosphine and 350 kg of toluene were added to the mixing reactor 2 via feed pipe 1 and mixed thoroughly to obtain a trichlorophosphine-toluene solution. The trichlorophosphine-toluene solution, 43.2 kg (590.6 mol, 1.0 eq) of n-butylamine, and 16.5 kg (590.6 mol, 1.0 eq) of nitrogen were pumped into the microchannel reactor 6 via pipe 501 through pipes 201, 3, and 4 via calibrated flow pump 5. The reactor temperature was set to 20℃, and the reaction retention time was 70 s. The injection rates were: trichlorophosphine-toluene solution 156.4 g / min, n-butylamine 15 g / min, and nitrogen 5.7 g / min. The toluene solution in the reaction system at the outlet of reactor 6 is separated into two phases by gas-liquid separator 7. The gas phase is connected to the alkaline absorption device via outlet pipe 8, while the liquid phase is directly used for the next reaction. The obtained N-n-butyldichlorothiophosphoryltoluene solution and liquid ammonia are injected into tubular reactor 12 via calibrated flow pumps 11 through pipes 9 and 10, respectively. The injection rate of N-n-butyldichlorothiophosphoryltoluene solution is 79.9 g / min, and the injection rate of liquid ammonia is 8.5 g / min. They enter the tubular reactor with an inner diameter of 20 mm. The reactor temperature is set at 20℃, and the reaction residence time is 20 minutes. After the reaction is completed, water is added directly, stirred, and allowed to stand for layering. The aqueous phase is extracted twice with toluene. After combining the extracts, the organic phase is distilled under reduced pressure to recover about 80%. The residue is cooled and crystallized to obtain the product n-butylthiophosphoryltriamine solid. After drying, 93.0 kg of white solid is obtained, with a yield of 93.5% and a purity of 98.8%.

[0043] The above are merely some preferred embodiments of the present invention, and the present invention is not limited to the contents of these embodiments. For those skilled in the art, various changes and modifications can be made within the scope of the present invention's technical solutions, and any such changes and modifications are within the protection scope of the present invention.

Claims

1. A continuous reaction apparatus for N-n-butylthiophosphoric triamine, characterized in that, include: A mixing vessel (2) with a feeding pipe (1) fixedly connected to the top; a microchannel reactor (6) connected to the outlet of the mixing vessel (2) via a first connecting pipe (201); a gas-liquid separator (7) connected to the outlet of the microchannel reactor (6) via a third connecting pipe (601); a liquid outlet pipe (9) fixedly connected to the bottom of the gas-liquid separator (7); a second flow pump (11) fixedly connected to the end of the liquid outlet pipe (9) away from the gas-liquid separator (7); a tubular reactor (12) connected to a fourth connecting pipe (201). 1101) is connected to the second flow pump (11); the second flow pump (11) is fixedly connected to a liquid ammonia feeding pipe (10); the tail end of the first connecting pipe (201) is fixedly connected to a first flow pump (5); the first flow pump (5) is fixedly connected to a n-butylamine feeding pipe (3) and a nitrogen feeding pipe (4); the output end of the first flow pump (5) is also fixedly connected to a second connecting pipe (501), and the second connecting pipe (501) is connected to the microchannel reactor (6).

2. The continuous reaction apparatus for N-n-butylthiophosphoric triamine according to claim 1, characterized in that: An outlet pipe (8) is fixedly connected to the top side wall of the gas-liquid separator (7).

3. A continuous preparation method for N-n-butylthiophosphoric triamine, using the preparation equipment described in claim 1 or 2, characterized in that, Includes the following steps: (1) Trichlorophosphorus is used as the starting material and mixed with solvent in a mixing tank (2) to prepare a trichlorophosphorus solution. The trichlorophosphorus solution, n-butylamine and inert gas are added to the microchannel reactor (6) through the first connecting pipe (201), the n-butylamine feeding pipe (3) and the nitrogen feeding pipe (4) respectively through the first flow pump (5) to carry out the substitution reaction. The hydrogen chloride gas is separated by the gas-liquid separator (7) to obtain N-n-butyldichlorothiophosphoramide solution. (2) The N-n-butyldichlorothiophosphoramide solution and liquid ammonia were added to the tubular reactor (12) through the outlet pipe (9) and the liquid ammonia feeding pipe (10) via the second flow pump (11) to obtain the N-n-butyldichlorothiophosphoramide solution. (3) The N-n-butylthiophosphoric triamine solution was extracted and washed, the organic phase was concentrated and then crystallized, separated and dried to obtain high-purity N-n-butylthiophosphoric triamine.

4. The continuous preparation method of N-n-butylthiophosphoric triamine according to claim 3, characterized in that: In step (1), the concentration of the trichlorophosphorus solution is 5%~50%; the reaction temperature is 0~60℃.

5. The continuous preparation method of N-n-butylthiophosphoric triamine according to claim 3, characterized in that: In step (1), the molar ratio of trichlorophosphorus, n-butylamine and inert gas is 1:0.8~1.2:0.5~1.

5.

6. The continuous preparation method of N-n-butylthiophosphoric triamine according to claim 3, characterized in that: In step (1), the solvent is selected from toluene, dichloromethane, dichloroethane, chlorobenzene, anisole, isopropyl acetate or 2-methyltetrahydrofuran; the inert gas is selected from nitrogen or argon.

7. The continuous preparation method of N-n-butylthiophosphoric triamine according to claim 3, characterized in that: In step (1), the flow rate of trichlorophosphorus solution is 20~500 g / min; the flow rate of n-butylamine is 2~50 g / min; the flow rate of nitrogen is 0.5~50 g / min; and the residence time of the microchannel reaction is 20~600 seconds.

8. The continuous preparation method of N-n-butylthiophosphoric triamine according to claim 3, characterized in that: In step (2), the molar ratio of N-n-butyldichlorothiophosphoramide to liquid ammonia is 1:2~100; the reaction temperature is 0~50℃; the flow rate of the N-n-butyldichlorothiophosphoramide solution is 20~600 g / min; and the flow rate of liquid ammonia is 2~60 g / min.

9. The continuous preparation method of N-n-butylthiophosphoric triamine according to claim 3, characterized in that: In step (2), the inner diameter of the pipeline reactor is 5-200 mm; the reaction residence time is 5-60 minutes; and the length of the pipeline reactor is 1-500 meters.

10. The continuous preparation method of N-n-butylthiophosphoric triamine according to claim 3, characterized in that: In step (2), the post-processing is as follows: after the reaction is completed, water is added to quench the reaction, the layers are extracted and separated, the organic phase is concentrated and crystallized to obtain the product n-butylthiophosphoric triamine, and the aqueous phase is treated to recover the by-product ammonium chloride.

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