Preparation and purification system and method of 5-aminotetrazolyl monohydrate

Abstract

The present invention relates to the preparation and purification field of 5-aminotetrazole monohydrate, and specifically provides a preparation and purification system and method of 5-aminotetrazole monohydrate, which is intended to solve the low safety of 5-aminotetrazole monohydrate production system and the problem of being difficult to meet large-scale high-purity products. For this purpose, the preparation and purification system of the present invention includes: a reactor, an organic solvent storage tank, a cyanamide aqueous solution storage tank, a separator, a purification tank and a drying device. The two-phase reaction system and method constructed by the present invention have few by-products during the reaction process, and a high reaction conversion rate, which greatly improves the purity of the product and is suitable for large-scale industrial production.

Description

Technical Field

[0001] The present invention relates to the field of preparation and purification of 5-aminotetrazole monohydrate, and specifically provides a system and method for preparing and purifying 5-aminotetrazole monohydrate. Background Art

[0002] With the increasing demand for display panels, display panels are being used more and more widely in computers, mobile phones, automobiles, home appliances and other fields. 5-Aminotetrazole, as an additive for display etching solution, is a consumable product. The market demand for it is increasing. At the same time, high product quality requirements are required, and batch quality stability of the product is required.

[0003] The purity of etching fluid largely determines product performance, yield, and reliability, a crucial aspect of modern display panel technology. With continuous technological advancements, pixel sizes and circuit line widths in display panels have shrunk to micrometers or even nanometers. At these fine scales, even trace amounts of impurities in the etching fluid, such as metal ions or particulate matter, can significantly impact the etching process. These impurities can accelerate or inhibit the etching reaction in localized areas, or cause incomplete etching, leaving unetched residue. These issues directly impact the quality and performance of display panels. Therefore, the stringent purity requirements for etching fluids in display panels reflect the inevitable trend of continuous technological upgrades (e.g., the pursuit of higher resolution and flexible displays) and represent a challenge facing the entire display panel industry chain in reducing costs and improving efficiency.

[0004] Currently, the main problems with the synthesis system of 5-aminotetrazole are poor production safety, high risk of reaction process, and unsuitability for industrial production. Some preparation systems use hydrazine hydrate and sodium nitrite to react with cyanamide under acidic conditions to produce 5-aminotetrazole. This process system involves a dangerous process and the reaction process is highly dangerous. At the same time, there is a process that uses cyanamide and sodium azide to react to prepare 5-aminotetrazole. The pH of the aqueous solution of cyanamide is 4-5, which is an acidic solution. Under acidic conditions, it will react with sodium azide to produce hydrazoic acid, which is highly toxic and has poor production safety, making it unsuitable for industrial production. The 5-aminotetrazole prepared in the existing technology also has the problem of incomplete separation and purification, resulting in the product purity not meeting the quality requirements of the continuous iteration and upgrading of display panels.

[0005] 5-Aminotetrazole monohydrate is a molecular structure found in 5-aminotetrazole and is used as an additive in etching solutions. The increasing market demand for display panels necessitates a production system capable of high yield, safe reaction conditions, and excellent product stability. Etching solutions also have stringent requirements for impurities; even trace amounts can affect the display quality. This requires that the 5-aminotetrazole monohydrate used in the etching solution be free of impurities. Advanced separation and purification techniques are employed to obtain very high-purity 5-aminotetrazole monohydrate.

[0006] Therefore, how to build a large-scale, industrialized, and safe preparation and purification system to meet the market demand for high-purity 5-aminotetrazole monohydrate has become an urgent problem to be solved. Summary of the Invention

[0007] In order to overcome the above-mentioned defects, the present invention provides a system and method for preparing and purifying 5-aminotetrazole monohydrate. The preparation and purification system and method of the present invention significantly improve the safety and efficiency of the entire preparation and purification system, not only obtaining high-purity 5-aminotetrazole monohydrate, but also facilitating the industrialization and large-scale production of 5-aminotetrazole monohydrate.

[0008] In a first aspect, the present invention provides a system for preparing and purifying 5-aminotetrazole monohydrate, comprising:

[0009] Reactor, organic solvent storage tank, cyanamide aqueous solution storage tank, separator, purification tank and drying device; among which,

[0010] The reactor is provided with a stirring paddle, a trimethylsilyl azide feed port and a first discharge port, wherein the stirring paddle is located inside the reactor, and the reactor is connected to the organic solvent storage tank and the monocyanamide aqueous solution storage tank respectively;

[0011] The separator is provided with a first feed port, a second discharge port and a third discharge port, wherein the first feed port is connected to the first discharge port;

[0012] The purification tank is provided with a second feed port, a pH adjuster feed port and a fourth discharge port, and the second feed port is connected to the third discharge port;

[0013] The fourth discharge port is connected to the drying device.

[0014] Furthermore, a reflux port is provided on the separator, and the second discharge port is connected to the reflux port.

[0015] Furthermore, the second discharge port is an organic phase discharge port, and the third discharge port is an aqueous phase discharge port; and / or

[0016] The fourth discharge port is a solid phase discharge port.

[0017] Furthermore, the separator is a gravity separation tank; and / or

[0018] The purification tank is a centrifuge; and / or

[0019] The reactor and the purification tank are respectively connected with a heat exchanger.

[0020] In a second aspect, the present invention provides a method for preparing and purifying 5-aminotetrazole monohydrate using the system described in the first aspect, comprising:

[0021] S1, controlling the stirring paddle of the reactor to start stirring, respectively controlling the organic solvent storage tank to input the organic solvent into the reactor and the cyanamide aqueous solution storage tank to input the cyanamide aqueous solution into the reactor, and controlling the reactor to heat up to a first preset temperature;

[0022] S2, at the first preset temperature, adding trimethylsilyl azide dropwise into the reactor through the trimethylsilyl azide feed port, and keeping the temperature until the reaction is complete;

[0023] S3, after the temperature of the reactor is cooled to 10° C. to 15° C., the product of the reactor is subjected to solid-liquid separation using a separator and a purification tank;

[0024] S4, drying the separated solid phase until the water content is 17.4%-17.6%.

[0025] Furthermore, in step S1, the organic solvent includes: one or more of toluene, benzene, and xylene; and / or

[0026] The mass fraction of the cyanamide aqueous solution is 50%; and / or

[0027] The first preset temperature is 40-50°C; and / or

[0028] In step S4, the drying temperature is 60-65° C. and the drying time is 2-4 hours.

[0029] Furthermore, in step S2, the dripping rate of trimethylsilyl azide is 100 kg-120 kg / h; and / or

[0030] The insulation time is 6-9 hours; and / or

[0031] The molar ratio of the cyanamide aqueous solution to trimethylsilyl azide is 1:(1-1.3), and the mass ratio of the cyanamide aqueous solution to the organic solvent is 1:(2-4).

[0032] Furthermore, the molar ratio of the aqueous cyanamide solution to trimethylsilyl azide is 1:(1.1-1.3).

[0033] Furthermore, the mass ratio of the cyanamide aqueous solution to the organic solvent is 1:3.

[0034] Furthermore, the solid-liquid separation of the product of the reactor based on the separator and the purification tank in step S3 includes:

[0035] S31, inputting the cooled material from the reactor into a separator;

[0036] S32, allowing the mixture to stand in a separator for phase separation to obtain an aqueous phase and an organic phase;

[0037] S33, feeding the aqueous phase into a purification tank, and feeding a pH adjuster through a pH adjuster feed port to adjust the pH of the aqueous phase in the purification tank to 3-4;

[0038] S34, controlling the purification tank to cool to a second preset temperature, and separating the solid phase.

[0039] Furthermore, the organic phase in step S32 is discharged from the second discharge port and then recycled; and / or

[0040] In step S33, the second preset temperature is 0 to -5°C.

[0041] The above one or more technical solutions of the present invention have at least one or more of the following beneficial effects:

[0042] The present invention designs a preparation and purification system for 5-aminotetrazole monohydrate, which has the advantage of high safety and is suitable for industrial production.

[0043] The two-phase reaction system and method constructed by the present invention have few by-products in the reaction process, high reaction conversion rate, and greatly improved product purity.

[0044] The 5-aminotetrazole monohydrate prepared by the system of the present invention can have an organic phase that can be recycled and reused, and a high-purity product can be obtained through effective multi-stage separation and purification. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The disclosure of the present invention will be more easily understood with reference to the accompanying drawings. Those skilled in the art will readily appreciate that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Furthermore, similar numbers in the drawings represent similar components, wherein:

[0046] Figure 1 1 is a schematic diagram of the main structure of a system for preparing and purifying 5-aminotetrazole monohydrate according to one embodiment of the present invention;

[0047] Figure 2 is an infrared spectrum of 5-aminotetrazole monohydrate prepared according to one embodiment of the present invention;

[0048] Figure 3 is an HPLC spectrum of 5-aminotetrazole monohydrate prepared according to one embodiment of the present invention;

[0049] Figure 4 This is the HPLC spectrum of 5-aminotetrazolyl monohydrate standard.

[0050] Reference Signs List :

[0051] 1: Reactor; 1-1: Stirring paddle; 1-2: Trimethylsilylazide feed port; 1-3: First discharge port; 2: Organic solvent storage tank; 3: Cyanamide aqueous solution storage tank; 4: Separator; 4-1: First feed port; 4-2: Second discharge port; 4-3: Third discharge port; 4-4: Reflux port; 5: Purification tank; 5-1: Second feed port; 5-2: pH adjuster feed port; 5-3: Fourth discharge port; 6: Drying device. DETAILED DESCRIPTION

[0052] Some embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0053] Reference Figure 1 The present invention provides a preparation and purification system for 5-aminotetrazole monohydrate, comprising:

[0054] Reactor 1, organic solvent storage tank 2, cyanamide aqueous solution storage tank 3, separator 4, purification tank 5 and drying device 6.

[0055] The following describes the connection relationship and function of each device in the system.

[0056] The reactor 1 is provided with a stirring paddle 1-1, a trimethylsilyl azide feed port 1-2 and a first discharge port 1-3.

[0057] The reactor 1 is a hollow cavity.

[0058] The stirring paddle 1 - 1 is located inside the reactor 1 and is used to stir the material in the cavity of the reactor 1 .

[0059] The reactor 1 is connected to the organic solvent storage tank 2 and the cyanamide aqueous solution storage tank 3. The organic solvent storage tank 2 stores organic solvents such as toluene, benzene, xylene, etc. The cyanamide aqueous solution storage tank 3 stores cyanamide aqueous solution.

[0060] The mass fraction of the cyanamide aqueous solution is 50%.

[0061] The reactor 1 is also provided with a trimethylsilyl azide feed port 1-2 for feeding trimethylsilyl azide into the reactor 1. The reactor 1 is also provided with a first discharge port 1-3 for discharging the reacted material.

[0062] The separator 4 is provided with a first feed port 4-1, a second discharge port 4-2 and a third discharge port 4-3.

[0063] The first feed port 4-1 is connected to the first discharge port 1-3, thereby achieving communication between the reactor 1 and the separator 4. The material in the reactor 1 is fed into the separator 4 through the first discharge port 1-3 and the first feed port 4-1, and is separated and purified to obtain an aqueous phase and an organic phase.

[0064] In one embodiment, the second discharge port 4-2 in the separator 4 is an organic phase discharge port for discharging the organic phase separated in the separator 4. The third discharge port 4-3 is an aqueous phase discharge port for discharging the aqueous phase separated in the separator 4.

[0065] In one embodiment, the separator 4 is a gravity separation tank, which separates the organic phase and the aqueous phase in a static state to achieve purification of the system in the separator 4.

[0066] In one embodiment, the separator 4 is further provided with a reflux port 4-4, and the second discharge port

[0067] 4-2 is connected to the reflux port 4-4. The organic phase can be recycled to improve resource utilization.

[0068] The purification tank 5 is provided with a second feed port 5-1, a pH adjuster feed port 5-2 and a fourth discharge port 5-3.

[0069] The second feed port 5-1 is connected to the third discharge port 4-3, thereby achieving communication between the separator 4 and the purification tank 5. The third discharge port 4-3 outputs the water phase separated in the separator 4 into the purification tank 5, where it is further purified.

[0070] The pH adjuster feed port 5-2 on the purification tank 5 is used to input a pH adjuster, such as an acid or base, to adjust the pH value of the material in the purification tank 5, and finally the purification tank 5 outputs the purified solid phase. The fourth discharge port 5-3 is a solid phase output port for outputting the solid phase after purification and separation in the purification tank 5.

[0071] In one embodiment, the purification tank 5 is a centrifuge to improve the efficiency of solid phase separation.

[0072] The fourth discharge port 5-3 is connected to the drying device 6. The solid phase after purification and separation in the purification tank 5 enters the drying device 6 for drying.

[0073] In one embodiment, the reactor 1 and the purification tank 5 are respectively connected to a heat exchanger. Specifically, the reactor 1 is connected to a first heat exchanger for controlling the temperature of the reactor 1 so that the material in the reactor 1 reaches a preset temperature.

[0074] The purification tank 5 is connected to a second heat exchanger for controlling the temperature of the purification tank 5 so as to adjust the temperature of the material in the purification tank 5 to reach a preset temperature.

[0075] In one embodiment, in order to improve the material conveying efficiency, a first conveying pump is provided between the first feed port 4-1 and the first discharge port 1-3, a second conveying pump is provided between the second discharge port 4-2 and the reflux port 4-4, a third conveying pump is provided between the fourth discharge port 5-3 and the drying device 6, and a fourth conveying pump is provided between the third discharge port 4-3 and the second feed port 5-1.

[0076] The present invention also provides a method for preparing and purifying 5-aminotetrazole monohydrate using the above system, comprising:

[0077] S1, control the stirring paddle 1-1 of the reactor 1 to start stirring, control the organic solvent storage tank 2 to input the organic solvent into the reactor 1 and the cyanamide aqueous solution storage tank 3 to input the cyanamide aqueous solution into the reactor 1, and control the reactor 1 to heat up to a first preset temperature.

[0078] In step S1, an organic solvent and a cyanamide aqueous solution are added to a reactor 1 under stirring, and then the temperature of the reactor 1 is controlled to increase.

[0079] In one embodiment, the organic solvent in step S1 includes one or more of toluene, benzene, and xylene.

[0080] In one embodiment, the mass fraction of the cyanamide aqueous solution input from the cyanamide aqueous solution storage tank 3 to the reactor 1 is 50%.

[0081] In one embodiment, the first preset temperature is 40-50°C.

[0082] S2, at the first preset temperature, adding trimethylsilyl azide dropwise into the reaction kettle 1 through the trimethylsilyl azide feed port 1-2, and keeping the temperature until the reaction is complete.

[0083] In one embodiment, the dripping rate of trimethylsilyl azide is 100 kg-120 kg / h.

[0084] In one embodiment, the insulation time is 6-9 hours.

[0085] In one embodiment, the molar ratio of the aqueous cyanamide solution to trimethylsilyl azide is 1:(1-1.5).

[0086] In one embodiment, a 50% by mass cyanamide aqueous solution is used, and the molar ratio of the cyanamide aqueous solution to trimethylsilyl azide is 1:(1.1-1.3).

[0087] In one embodiment, in the actual preparation process, the trimethylsilyl azide of the present invention is a commercially purchased trimethylsilyl azide solution with a mass fraction of 98%.

[0088] In one embodiment, the mass ratio of the cyanamide aqueous solution to the organic solvent is 1:(2-4).

[0089] In one embodiment, the mass ratio of the cyanamide aqueous solution to the organic solvent is 1:3.

[0090] S3 , after the temperature of the reactor 1 is cooled to 10° C. to 15° C., the product of the reactor 1 is subjected to solid-liquid separation based on the separator 4 and the purification tank 5 .

[0091] Separator 4 and purification tank 5 efficiently and effectively remove impurities, improving the purity of 5-aminotetrazolyl monohydrate. The separator physically separates the material and removes impurities, while purification tank 5 provides more refined purification, achieving high product purity. This combination optimizes the purification process, balancing efficiency and cost, and is suitable for the material purity requirements of the display panel industry.

[0092] In one embodiment, the step S3 is based on the separator 4 and the purification tank 5,

[0093] The solid-liquid separation of the product from reactor 1 includes:

[0094] S31, inputting the cooled material in the reactor 1 into the separator 4.

[0095] S32, allowing the mixture to stand in the separator 4 for phase separation to obtain an aqueous phase and an organic phase.

[0096] When the phases are separated in the separator 4, the temperature is consistent with the temperature of the reactor after the temperature is lowered in step S31.

[0097] That is, the separator 4 performs static phase separation at 10°C to 15°C.

[0098] Separator 4 performs rough separation first. Preliminary purification can reduce the load of subsequent purification steps and improve

[0099] High overall efficiency. In addition, it can also increase the concentration of the target material and make the material closer to the target purity by removing most of the impurities.

[0100] S33, the aqueous phase separated in the separator 4 is input into the purification tank 5, and the pH value is adjusted.

[0101] The pH regulator is input through the regulator feed port 5-2 to adjust the pH of the aqueous phase in the purification tank 5 to 3-4.

[0102] S34: After the purification tank 5 is cooled to a second preset temperature, the solid phase is separated. Further purification is performed in the purification tank 5 to raise the purity of the material to a higher level. The purity of the material of the present invention can reach over 99.9% after passing through the purification tank 5, and trace impurities such as metal ions and anions can be selectively removed.

[0103] In one embodiment, the organic phase in step S32 is discharged from the second discharge port 4-2 and then recycled.

[0104] In one embodiment, in step S34, the second preset temperature is 0 to -5°C.

[0105] S4, drying the separated solid phase until the water content is 17.4%-17.6%.

[0106] In one embodiment, the drying temperature in step S4 is 60-65° C. and the drying time is 2-4 hours. After steps S1-S4, 5-aminotetrazole monohydrate is obtained. The synthetic route is:

[0107] .

[0108] The present invention also provides an etching solution for selectively etching copper and copper alloys.

[0109] The method comprises adopting the above preparation and purification system to prepare 5-aminotetrazolyl monohydrate, or obtaining 5-aminotetrazolyl monohydrate based on the above purification system and purification method.

[0110] The 5-aminotetrazole monohydrate obtained by the invention has the structural formula: The hydrate is adsorbed on the copper surface through the nitrogen atoms on the tetrazole ring and the amino group to form a protective film, which can inhibit the corrosion of the copper surface by H2O2, thereby reducing the static corrosion rate and removal rate of the copper sheet. Its main function in the copper etching solution is to act as a corrosion inhibitor, forming a protective film by adsorbing on the copper surface, thereby inhibiting the corrosion of the copper surface by H2O2 and improving the surface quality.

[0111] In one embodiment, the content of the 5-aminotetrazole monohydrate in the etching solution is 0.1-5 g / L.

[0112] The following examples illustrate the process for preparing 5-aminotetrazole monohydrate of the present invention.

[0113] Trimethylsilyl azide was a commercially available 98% trimethylsilyl azide solution.

[0114] use Figure 1 production system.

[0115] Example 1

[0116] S1, control the stirring paddle 1-1 of the reactor 1 to start stirring, control the organic solvent storage tank 2 to add 1500L of organic solvent toluene into the 5000L reactor 1, continue to control the cyanamide aqueous solution storage tank 3 to input 500kg of cyanamide aqueous solution with a mass concentration of 50% into the reactor 1 under stirring, turn on the first heat exchanger connected to the reactor 1, heat the reactor 1, and control the reactor temperature to 45°C.

[0117] S2, at 45 ° C, slowly add 753 kg of trimethylsilyl azide into the reactor 1 through the trimethylsilyl azide feed port 1-2, the addition rate of trimethylsilyl azide is 110 kg / h, and after the addition is completed, keep the reaction warm for 6 hours.

[0118] S3, take samples to check if the cyanamide reaction is complete and cool to 12°C.

[0119] S31, inputting the cooled material in the reactor 1 into the separator 4.

[0120] S32, separator 4 is allowed to stand at 12°C for phase separation. After the phase separation, an aqueous phase and an organic phase are obtained. The organic phase can be used for the next batch.

[0121] S33, the aqueous phase is input into the purification tank 5, and the pH is input through the pH regulator feed port 5-2.

[0122] The regulator, in this embodiment, is 724 kg of hydrochloric acid, which is used to adjust the pH of the aqueous phase in the purification tank 5 to 3-4.

[0123] S34, cooling the neutralized aqueous phase, controlling the temperature of the purification tank 5 to -2°C, and performing separation to separate the solid phase.

[0124] S4, drying the separated solid phase product at 60-65°C for 2-4 hours until the water content is 17.4%-17.6%.

[0125] Example 1: 558.5 kg of 5-aminotetrazole monohydrate was obtained, and the product yield was 91.1%.

[0126] The 5-aminotetrazole monohydrate obtained in Example 1 was tested, and the test results are shown in FIG. Figure 2-4 .

[0127] Figure 2The infrared spectrum of 5-aminotetrazolyl monohydrate is shown. By observing the spectrum, the characteristic absorption peaks of key functional groups can be clearly identified, and the appearance of these peaks is consistent with the theoretical characteristic absorption peaks of known standard spectra. Figure 2 Comparison and analysis of the spectrum with existing standard infrared spectra confirmed that the positions of the characteristic peaks and their relative intensities were consistent. Furthermore, the absence of significant extraneous peaks further demonstrates that the system and method employed in the present invention can effectively ensure high purity of the product during the preparation of 5-aminotetrazole monohydrate.

[0128] To further demonstrate that the preparation and purification system of the present invention can effectively purify, separate, and cleanse the product, thereby obtaining a pure product with ultra-low impurity concentrations, the present invention conducted high-performance liquid chromatography (HPLC) testing. HPLC testing is considered one of the "gold standards" for verifying the purity of chemical substances, providing precise information on sample purity. Figure 3 shows the HPLC spectrum of 5-aminotetrazolyl hydrate, and Figure 4 The HPLC spectrum of the standard sample of 5-aminotetrazolyl hydrate is presented. Figure 3 and Figure 4 It can be clearly observed that the HPLC spectrum and impurity composition of the 5-aminotetrazole hydrate prepared by the method of the present invention are consistent with the impurity composition of its standard sample, and the purity and impurities of the product are consistent with the results of the standard, demonstrating the efficiency and reliability of the preparation and purification system and method of the present invention. It can ensure that the impurity content in the final product reaches an extremely low level, thereby meeting the relevant requirements for the application of high-purity 5-aminotetrazole monohydrate in etching solutions.

[0129] Example 2

[0130] S1, control the stirring paddle 1-1 of the reactor 1 to start stirring, control the organic solvent storage tank 2 to add 1500L of organic solvent xylene into the 5000L reactor 1, continue to control the cyanamide aqueous solution storage tank 3 to input 500kg of cyanamide aqueous solution with a mass concentration of 50% into the reactor 1 under stirring, turn on the first heat exchanger connected to the reactor 1, heat the reactor 1, and control the reactor temperature to 40°C.

[0131] S2, at 40 ° C, slowly add 821 kg of trimethylsilyl azide into the reactor 1 through the trimethylsilyl azide feed port 1-2, the addition rate of trimethylsilyl azide is 120 kg / h, and after the addition is completed, keep the reaction warm for 7 hours.

[0132] S3, take samples to check if the cyanamide reaction is complete and cool to 10°C.

[0133] S31, inputting the cooled material in the reactor 1 into the separator 4.

[0134] S32, separator 4 is allowed to stand at 10°C for phase separation. After the phase separation, an aqueous phase and an organic phase are obtained. The organic phase can be used for the next batch.

[0135] S33, the aqueous phase is input into the purification tank 5, and the pH is input through the pH regulator feed port 5-2.

[0136] The regulator, in this embodiment, is 292 kg of sulfuric acid, which is used to adjust the pH of the aqueous phase in the purification tank 5 to 3-4.

[0137] S34, cooling the neutralized aqueous phase, controlling the temperature of the purification tank 5 to 0°C, and performing separation to separate the solid phase.

[0138] S4, drying the separated solid phase product at 60-65°C for 2-4 hours until the water content is 17.4%-17.6%. Example 2 obtained 562.2 kg of 5-aminotetrazole monohydrate with a product yield of 91.7%.

[0139] Example 3

[0140] S1, control the stirring paddle 1-1 of the reactor 1 to start stirring, control the organic solvent storage tank 2 to add 1500L of organic solvent benzene into the 5000L reactor 1, continue to control the cyanamide aqueous solution storage tank 3 to input 500kg of cyanamide aqueous solution with a mass concentration of 50% into the reactor 1 under stirring, turn on the first heat exchanger connected to the reactor 1, heat the reactor 1, and control the reactor temperature to 50°C.

[0141] S2, at 50 ° C, slowly add 890 kg of trimethylsilyl azide into the reactor 1 through the trimethylsilyl azide feed port 1-2, with a dropping rate of 100 kg / h. After the addition is completed, keep the reaction warm for 8 hours.

[0142] S3, take samples to check if the cyanamide reaction is complete and cool to 15°C.

[0143] S31, inputting the cooled material in the reactor 1 into the separator 4.

[0144] S32, separator 4 is allowed to stand at 15°C for phase separation. After the phase separation, an aqueous phase and an organic phase are obtained. The organic phase can be used for the next batch.

[0145] S33, the aqueous phase is input into the purification tank 5, and the pH is input through the pH regulator feed port 5-2.

[0146] The regulator, in this embodiment, is 724 kg of hydrochloric acid, which is used to adjust the pH of the aqueous phase in the purification tank 5 to 3-4.

[0147] S34, cooling the neutralized aqueous phase, controlling the temperature of the purification tank 5 to -2°C, and performing separation to separate the solid phase.

[0148] S4, drying the separated solid phase product at 60-65°C for 2-4 hours until the water content is 17.4%-17.6%. Example 3 obtained 564.6 kg of 5-aminotetrazole monohydrate, with a product yield of 92.1%.

[0149] Example 4

[0150] S1, control the stirring paddle 1-1 of the reactor 1 to start stirring, control the organic solvent storage tank 2 to add 1500L of organic solvent benzene into the 5000L reactor 1, continue to control the cyanamide aqueous solution storage tank 3 to input 500kg of cyanamide aqueous solution with a mass concentration of 50% into the reactor 1 under stirring, turn on the first heat exchanger connected to the reactor 1, heat the reactor 1, and control the reactor temperature to 50°C.

[0151] S2, at 50 ° C, slowly add 753 kg of trimethylsilyl azide into the reactor 1 through the trimethylsilyl azide feed port 1-2, with a dropping rate of 100 kg / h. After the addition is completed, keep the reaction warm for 9 hours.

[0152] S3, take samples to check if the cyanamide reaction is complete and cool to 11°C.

[0153] S31, inputting the cooled material in the reactor 1 into the separator 4.

[0154] S32, separator 4 is allowed to stand at 11°C for phase separation. After the phase separation, an aqueous phase and an organic phase are obtained. The organic phase can be used for the next batch.

[0155] S33, the aqueous phase is input into the purification tank 5, and the pH is input through the pH regulator feed port 5-2.

[0156] The regulator, in this embodiment, is 724 kg of hydrochloric acid, which is used to adjust the pH of the aqueous phase in the purification tank 5 to 3-4.

[0157] S34, cooling the neutralized aqueous phase, controlling the temperature of the purification tank 5 to -5°C, and performing separation to separate the solid phase.

[0158] S4, drying the separated solid phase product at 60-65°C for 2-4 hours until the water content is 17.4%-17.6%. Example 4 obtained 562.2 kg of 5-aminotetrazole monohydrate with a product yield of 91.7%.

[0159] Example 5

[0160] S1, control the stirring paddle 1-1 of the reactor 1 to start stirring, control the organic solvent storage tank 2 to 5000L

[0161] Toluene, an organic solvent, was added to reactor 1. A 50% cyanamide aqueous solution was supplied from cyanamide aqueous solution storage tank 3 while stirring. A first heat exchanger connected to reactor 1 was opened to heat reactor 1 to a temperature of 42° C. The mass ratio of the cyanamide aqueous solution to the toluene organic solvent was 1:3.

[0162] S2. At 42°C, trimethylsilyl azide was slowly added dropwise to reactor 1 through trimethylsilyl azide inlet 1-2 at a rate of 111 kg / h. After the addition was complete, the reaction was maintained at this temperature for 6 hours. The molar ratio of the cyanamide aqueous solution to trimethylsilyl azide was 1:1.

[0163] S3, take samples to check if the cyanamide reaction is complete and cool to 14°C.

[0164] S31, inputting the cooled material in the reactor 1 into the separator 4.

[0165] S32, separator 4 is allowed to stand at 14°C for phase separation. After the phase separation, an aqueous phase and an organic phase are obtained. The organic phase can be used for the next batch.

[0166] S33, the aqueous phase is input into the purification tank 5, and the pH is input through the pH regulator feed port 5-2.

[0167] The regulator, in this embodiment, is hydrochloric acid, which is input until the pH of the aqueous phase in the purification tank 5 is 3-4.

[0168] S34, cooling the neutralized aqueous phase, controlling the temperature of the purification tank 5 to -3°C, and performing separation to separate the solid phase.

[0169] S4, drying the separated solid phase product at 60-65°C for 2-4 hours until the water content is 17.4%-17.6%.

[0170] Example 6

[0171] The only difference between this embodiment and embodiment 1 is that in embodiment 6, the molar ratio of the cyanamide aqueous solution to trimethylsilyl azide is 1:1.5, and the mass ratio of the cyanamide aqueous solution to the organic solvent is 1:4.

[0172] Example 7

[0173] The only difference between this embodiment and embodiment 1 is that in embodiment 6, the molar ratio of the aqueous cyanamide solution to trimethylsilyl azide is 1:1.1, and the mass ratio of the aqueous cyanamide solution to the organic solvent is 1:2.

[0174] Example 8

[0175] The only difference between this embodiment and embodiment 1 is that in embodiment 6, the molar ratio of the cyanamide aqueous solution to trimethylsilyl azide is 1:1.3, and the mass ratio of the cyanamide aqueous solution to the organic solvent is 1:3.

[0176] The yields of 5-aminotetrazole monohydrate obtained in Examples 5-8 were all greater than 90%.

[0177] The system of the present invention is used to prepare and purify 5-aminotetrazolyl monohydrate, which has the following advantages:

[0178] (1) Mild reaction conditions: The reaction process does not involve the use of diazotization process, the reaction condensation conditions are 40-50 ° C, and the reaction conditions are mild.

[0179] (2) Safe reaction conditions: The process of the present invention uses trimethylsilyl azide as the reaction raw material, which can exist stably under acidic conditions and will not generate hydrazoic acid under the acidic conditions of monocyanamide. This avoids the danger of sodium azide decomposing to produce hydrazoic acid due to the acidity of monocyanamide, and the reaction process is safer.

[0180] (3) Two-phase reaction, high atom economy: This reaction process adopts a two-phase reaction. The aqueous solution of monocyanamide is easily soluble in water, and trimethylsilyl azide is easily soluble in organic solvents. The 5-aminotetrazole product generated by the two-phase reaction will dissolve in the aqueous phase. In the reaction process, trimethylsilyl azide is excessive, and the monocyanamide reacts completely. The remaining trimethylsilyl azide is in the organic phase and can be recycled and reused after phase separation. It has high atom utilization and few by-products, which is more suitable for industrial production.

[0181] (4) Two-phase reaction, with few by-products, high reaction conversion rate, and product yield ≥90%.

[0182] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effects of the present invention, different steps do not have to be performed in such an order. They can be performed simultaneously (in parallel) or in other orders. These changes are within the scope of protection of the present invention.

[0183] Thus far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A system for preparing and purifying 5-aminotetrazole monohydrate, characterized in that: include: A reaction kettle (1), an organic solvent storage tank (2), a cyanamide aqueous solution storage tank (3), a separator (4), a purification tank (5) and a drying device (6); wherein, The reactor (1) is provided with a stirring paddle (1-1), a trimethylsilyl azide feed port (1-2) and a first discharge port (1-3); the stirring paddle (1-1) is located inside the reactor (1); and the reactor (1) is connected to the organic solvent storage tank (2) and the monocyanamide aqueous solution storage tank (3), respectively; The separator (4) is provided with a first feed port (4-1), a second discharge port (4-2) and a third discharge port (4-3), wherein the first feed port (4-1) is connected to the first discharge port (1-3); The purification tank (5) is provided with a second feed port (5-1), a pH regulator feed port (5-2) and a fourth discharge port (5-3), and the second feed port (5-1) is connected to the third discharge port (4-3); The fourth discharge port (5-3) is connected to the drying device (6).

2. The system according to claim 1, wherein: A reflux port (4-4) is also provided on the separator (4), and the second discharge port (4-2) is connected to the reflux port (4-4).

3. The system according to claim 1 or 2, characterized in that The second discharge port (4-2) is an organic phase discharge port, and the third discharge port (4-3) is an aqueous phase discharge port; and / or The fourth discharge port (5-3) is a solid phase discharge port.

4. The system according to claim 1, wherein: The separator (4) is a gravity separation tank; and / or The purification tank (5) is a centrifuge; and / or The reactor (1) and the purification tank (5) are respectively connected to a heat exchanger.

5. A method for preparing and purifying 5-aminotetrazole monohydrate using the system according to any one of claims 1 to 4, characterized in that: include: S1, controlling the stirring paddle (1-1) of the reactor (1) to start stirring, controlling the organic solvent storage tank (2) to input the organic solvent into the reactor (1) and the cyanamide aqueous solution storage tank (3) to input the cyanamide aqueous solution into the reactor (1), and controlling the reactor (1) to heat up to a first preset temperature; S2, at the first preset temperature, adding trimethylsilyl azide dropwise into the reaction kettle (1) through the trimethylsilyl azide feed port (1-2), and keeping the temperature until the reaction is complete; S3, after the temperature of the reactor (1) is cooled to 10°C to 15°C, the product of the reactor (1) is subjected to solid-liquid separation based on the separator (4) and the purification tank (5); S4, drying the separated solid phase until the water content is 17.4%-17.6%; In step S1, the organic solvent includes: one or more of toluene, benzene, and xylene; The first preset temperature is 40-50°C.

6. The method according to claim 5, characterized in that The mass fraction of the cyanamide aqueous solution is 50%; In step S4, the drying temperature is 60-65° C. and the drying time is 2-4 hours.

7. The method according to claim 5, characterized in that In step S2, the addition rate of trimethylsilyl azide is 100 kg to 120 kg / h; and / or The insulation time is 6-9 hours; and / or The molar ratio of the cyanamide aqueous solution to trimethylsilyl azide is 1:(1-1.3), The mass ratio of the cyanamide aqueous solution to the organic solvent is 1:(2-4).

8. The method according to claim 7, characterized in that The molar ratio of the aqueous cyanamide solution to trimethylsilyl azide is 1:(1.1-1.3); and / or The mass ratio of the cyanamide aqueous solution to the organic solvent is 1:

3.

9. The method according to claim 5, characterized in that The solid-liquid separation of the product of the reactor (1) based on the separator (4) and the purification tank (5) in step S3 includes: S31, feeding the cooled material from the reactor (1) into the separator (4); S32, allowing the mixture to stand in a separator (4) for phase separation to obtain an aqueous phase and an organic phase; S33, the aqueous phase is fed into the purification tank (5) through the pH regulator feed port (5-2) Inputting a pH regulator to adjust the pH of the aqueous phase in the purification tank (5) to 3-4; S34, controlling the purification tank (5) to cool to a second preset temperature, and separating the solid phase.

10. The method according to claim 9, characterized in that The organic phase in step S32 is discharged from the second discharge port (4-2) and then recycled; and / or In step S34, the second preset temperature is 0 to -5°C.

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