CN112321524B

CN112321524B - Method for continuously preparing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan by adopting microchannel reactor

Info

Publication number: CN112321524B
Application number: CN202011246499.6A
Authority: CN
Inventors: 郭凯; 袁鑫; 邱江凯; 覃龙州; 孙蕲; 段秀
Original assignee: Nanjing Tech University
Current assignee: Nanjing Tech University
Priority date: 2020-11-10
Filing date: 2020-11-10
Publication date: 2022-03-04
Anticipated expiration: 2040-11-10
Also published as: CN112321524A

Abstract

The invention discloses a method for continuously preparing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan by adopting a microchannel reactor, which comprises the following steps: (1) respectively and simultaneously pumping the 3-amino-4-amidoxime furazan solution and the sodium nitrite aqueous solution into a first micro mixer in a microchannel reactor device, mixing, and introducing into a first reaction module for a first reaction; (2) and (2) simultaneously pumping the effluent of the first reaction module and a sodium carbonate solution into a second micro mixer in a microchannel reactor device respectively, mixing, introducing into a second reaction module, and carrying out a second reaction to obtain an effluent containing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan. The invention relates to a method for separating an intermediate 3-amino-4-amidoxime furazan, which realizes the efficient and continuous preparation of 3, 4-bis (4 '-amidofurazan-3' -yl) furoxan by a one-pot two-step method.

Description

Method for continuously preparing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan by adopting microchannel reactor

Technical Field

The invention belongs to the field of chemical synthesis, and particularly relates to a method for continuously preparing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF) by adopting a microchannel reactor.

Background

The furazan compound has the characteristics of high standard enthalpy of formation, rich nitrogen and oxygen, high energy, high density, good molecular thermodynamic stability and the like, and a large number of researches show that for designing a high-energy density compound with C, N, O atoms, a furazan group is a very effective structural unit and is an energetic compound with important development and application values. 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF) is an important furazan compound, and the DATF is used as a precursor to synthesize a series of excellent novel compounds containing nitro, azido, azo, azoxy and the like.

At present, a common synthesis method of DATF is to prepare a key intermediate AAOF by using malononitrile as an initial raw material through nitrosation, the AAOF is subjected to diazotization under the action of hydrochloric acid and sodium nitrite, then a molecule of nitrogen is removed, halogenation is carried out to generate 3-amino-4-acyl chloride hydroxyimino furazan (ACOF), the ACOF is subjected to separation and purification, then a molecule of HCl is removed under the action of diluted alkali, and 1, 3-dipolarization reaction is carried out to finally obtain a target product, namely 3, 4-bis (4 '-amino furazan-3' -yl) furoxan (DATF), wherein the specific chemical reaction formula is as follows:

the traditional method for preparing DATF from AAOF generally needs to be carried out in two steps, the total yield of the two-step reaction is 53%, and an intermediate ACOF needs to be separated out [ chemical reports, 2011, 69 (14): 1673-1680]. Therefore, the traditional process has a series of problems of complicated operation process, uncontrollable safety of large-scale production, long reaction time, more 'three wastes' emission, difficult engineering application and the like. In order to solve the above problems, a highly efficient process enhancement technology, i.e., a micro-flow field reaction technology, is needed to enhance the mass transfer and heat transfer of the reaction process.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the defects of the prior art, the invention provides a method for continuously preparing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan by adopting a microchannel reactor.

In order to solve the technical problem, the invention discloses a method for continuously preparing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF) by adopting a microchannel reactor, wherein the chemical reaction formula is shown as figure 4; specifically, the method comprises the following steps:

(1) mixing 3-amino-4-amidoxime furazan (AAOF) solution with sodium nitrite (NaNO)₂) Respectively and simultaneously pumping the aqueous solution into a first micro mixer in a micro-channel reactor device, mixing, and introducing into a first reaction module for a first reaction, namely a nitrosation reaction;

(2) simultaneously with the step (1), the effluent of the first reaction module was mixed with sodium carbonate (Na)₂CO₃) The solution is respectively pumped into a second micro mixer in the micro-channel reactor device at the same time, mixed and then introduced into a second reaction module for a second reaction (dehalogenation)Reaction) to obtain an effluent containing 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan.

Wherein the microchannel reactor device is shown in fig. 1 and comprises a first feeding pump, a second feeding pump, a third feeding pump, a first micromixer, a second micromixer, a first reaction module and a second reaction module; the first feeding pump and the second feeding pump are connected to the first micro mixer in a parallel mode, the first micro mixer, the first reaction module, the second micro mixer and the second reaction module are sequentially connected in series, and the third feeding pump and the first reaction module are connected to the second micro mixer in a parallel mode.

The pipe diameter size inner diameter of the first reaction module and the pipe diameter size inner diameter of the second reaction module are 0.5-5 mm, and the length of the first reaction module and the second reaction module is 0.5-40 m; the first reaction module and the second reaction module are of pore channel structures, and the pore channel material is polytetrafluoroethylene; preferably, the inner diameter of the pipe diameter of the first reaction module and the second reaction module is 0.3-1.8 mm, and the length of the pipe diameter of the first reaction module and the second reaction module is 8-18 m; further preferably, the first reaction module and the second reaction module have a pipe diameter size with an inner diameter of 1.5mm and a length of 10 m.

In the step (1), the solvent of the 3-amino-4-amidoximyl furazan solution is a mixed solvent of water and hydrochloric acid, or a mixed solvent of an organic solvent and hydrochloric acid; wherein the organic solvent is any one or a combination of several of Dichloromethane (DCM), N-dimethyl imide (DMF), dimethyl sulfoxide (DMSO), Tetrahydrofuran (THF), Ethyl Acetate (EA) and ethanol (EtOH); preferably, the solvent is a mixed solvent of water and hydrochloric acid.

In the step (1), the concentration of the 3-amino-4-amidoximyl furazan in the 3-amino-4-amidoximyl furazan solution is 0.1-5.0 mol/L, and preferably 0.1-2.0 mol/L.

In the step (1), the concentration of sodium nitrite in the sodium nitrite aqueous solution is 0.5-10.0 mol/L, preferably 0.5-5.0 mol/L.

In the step (1), the pumping rates of the 3-amino-4-amidoxime furazan solution and the sodium nitrite aqueous solution are both 0.2-10.0 mL/min, preferably 0.2-5.0 mL/min.

In the step (1), the reaction temperature of the first reaction is 0-20 ℃, and preferably 10-20 ℃.

In the step (1), the reaction residence time of the first reaction is 30 s-30 min, preferably 2-6 min, and more preferably 4-6 min.

In the step (2), the solvent of the sodium carbonate solution is a mixed solvent of water and tetrahydrofuran.

In the step (2), the concentration of sodium carbonate in the sodium carbonate solution is 0.1-1.0 mol/L, preferably 0.3-1.0 mol/L.

In the step (2), the pumping rate of the sodium carbonate solution is 0.2-10.0 mL/min, preferably 0.2-5.0 mL/min.

In the step (2), the reaction temperature of the second reaction is 0-30 ℃, and preferably 10-30 ℃.

In the step (2), the reaction residence time of the second reaction is 15s to 15min, preferably 1.5min to 4min, and more preferably 3 to 4 min.

Has the advantages that: compared with the prior art, the invention has the following advantages:

(1) the micro-flow field reaction technology greatly improves the mass transfer and heat transfer efficiency of the reaction, and greatly shortens the reaction time while improving the conversion rate of raw materials and the yield of products.

(2) The micro-flow field reaction technology adopts a continuous flow mode, has good material mixing effect and extremely low back mixing, and can effectively improve the reaction selectivity and further improve the product quality.

(3) The real-time online reaction volume is only dozens of milliliters to hundreds of milliliters, the safety is high, and the potential safety hazard is greatly reduced during engineering production.

(4) The separation procedure of the intermediate is avoided, the operation is greatly simplified, the reaction time is shortened, and the production efficiency is improved.

(5) The micro-flow field equipment has small floor area, simple and convenient operation and high matching degree with the specific process.

(6) The conversion rate of the raw materials can reach 80-98%, and the product yield can reach 50-76%.

(7) The preparation process disclosed by the invention is efficient, green and safe, and solves the problems of complicated operation steps, severe reaction, more side reactions, uncontrollable reaction safety, serious discharge of three wastes and the like in the traditional DATF preparation process.

(8) Compared with the traditional kettle type preparation process, the reaction process provided by the invention has the following advantages: firstly, the efficient and continuous preparation of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF) is realized by a 'one-pot two-step method' without separating an intermediate 3-amino-4-gem-oximido furazan (ACOF); the adopted micro-flow field reaction process has the advantages of short reaction time, high raw material conversion rate, high target product yield and the like. The novel micro-flow field reaction device has the characteristics of high heat and mass transfer efficiency, low price, convenience in transportation, convenience in cleaning, easiness in engineering amplification and the like. In conclusion, the method is simple to operate, low in cost and small in environmental pollution, not only effectively overcomes the defects of the traditional synthetic method, but also can continuously produce products with stable quality, and has a good industrial application prospect.

Drawings

The foregoing and/or other advantages of the invention will become further apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

FIG. 1 is a schematic flow chart of an apparatus for preparing a DATF microflow field.

FIG. 2 shows a hydrogen spectrum of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan.

FIG. 3 is a carbon spectrum of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan.

FIG. 4 is a reaction scheme of the present invention.

Detailed Description

The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Na described in the examples below₂CO₃The solvent of the solution is a mixed solvent of water and tetrahydrofuran, and the volume ratio of the water to the tetrahydrofuran is 2: 1.

Example 1

Weighing 1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximino furazan (AAOF), adding 14mL of water and 6mL of concentrated hydrochloric acid (37%) respectively, fully stirring and dissolving to obtain a material I, sucking by using a syringe, and placing on a syringe pump; 0.69g of sodium nitrite (NaNO) was weighed₂10mmol,1.0equiv) is added with proper distilled water and fully stirred and dissolved to prepare 10mL solution as a material II which is sucked by a syringe and then placed on a syringe pump; then 0.3mol/L of Na is prepared₂CO₃16mL of the solution was used as feed III, which was aspirated with a syringe and placed on a syringe pump. The feeding pump sets up into material I and material II simultaneously after the appropriate velocity of flow, and carry the material to miniflow field reaction module 1 after the intensive mixing and react. Wherein, the inner diameter of the pipeline used by the micro-flow field reaction module 1 is 1.5mm, the length is 10m, the volume is 17.7mL, the reaction temperature of the micro-flow field reaction module 1 is set to be 20 ℃, the feeding speed of the material I is 5.0mL/min, the feeding speed of the material II is 2.5mL/min, and the residence time of the reaction is 2.4 min. And pumping a material III into the reaction tank to be mixed with the reaction liquid, and conveying the mixture to the micro-flow field reaction module 2 for reaction after the mixture is fully mixed. Wherein the inner diameter of a pipeline of the micro-flow field reaction module 2 is 1.5mm, the length of the pipeline is 10m, the volume is 17.7mL, and the temperature of the reaction module 2 is set to be 20 ℃; the flow rate of feed III was 4.0mL/min and the residence time of the reaction was 1.5 min. Collecting reaction effluent in a collecting module, distilling under reduced pressure to remove organic solvent, cooling at 0 ℃, filtering and separating to obtain 0.72g of target product 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), wherein the nuclear magnetism is shown in figures 2 and 3, the conversion rate of raw materials is 85%, and the yield is 57%.

Example 2

Weighing 1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximino furazan (AAOF), adding 14mL of water and 6mL of concentrated hydrochloric acid (37%) respectively, fully stirring and dissolving to obtain a material I, sucking by using a syringe, and placing on a syringe pump; 0.69g NaNO was weighed₂(10mmol,1.0equiv) is dissolved by a proper amount of distilled water to prepare 10mL solution which is used as a material II, and the material II is sucked by a syringe and then is placed on a syringe pump; 0.3mol/L of Na is measured₂CO₃16mL of solution as feed III. The feeding pump sets a proper flow rate and then simultaneously pumps the material I and the material II, and the materials are mixed and then conveyed to the micro-flow field reaction module 1 for reaction. Wherein the inner diameter of a pipeline of the micro-flow field reaction module 1 is 2.0mm, the length of the pipeline is 6m, the volume is 18.4mL, and the reaction temperature of the module is set to be 20 ℃; the flow rate of material I was 5.0mL/min, the flow rate of material II was 2.5mL/min, and the reaction residence time was 2.5 min. And pumping a material III to be fully mixed with the reaction liquid, and conveying the mixture to the micro-flow field reaction module 2 for reaction. Wherein the inner diameter of a pipeline of the micro-flow field reaction module 1 is 2.0mm, the length of the pipeline is 6m, the volume is 18.4mL, and the reaction temperature of the module is set to be 20 ℃; the flow rate of material III was 4.0mL/min and the reaction residence time was 1.6 min. Collecting reaction effluent in a collecting module, distilling under reduced pressure to remove an organic solvent, cooling at 0 ℃, filtering and separating to obtain 0.65g of a target product 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), wherein the conversion rate of the raw material is 81 percent, and the yield is 52 percent.

Example 3

Weighing 1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximino furazan (AAOF), respectively adding 14mL of water and 6mL of concentrated hydrochloric acid (37%), fully stirring and dissolving to obtain a material I, sucking by using a syringe, and placing on a syringe pump; 0.69g NaNO was weighed₂(10mmol,1.0equiv) is dissolved in proper distilled water to prepare 10mL solution as a material II, the material II is sucked by a syringe and then is placed on a syringe pump, and the material II is sucked by the syringe and then is placed on the syringe pump; preparing 0.3mol/L of Na₂CO₃16mL of the solution was used as feed III, which was aspirated with a syringe and placed on a syringe pump. The feeding pump sets a proper flow rate and then simultaneously pumps the material I and the material II, and the materials are mixed and then conveyed to the micro-flow field reaction module 1 for reaction. Wherein the inner diameter of a pipeline of the micro-flow field reaction module 1 is 1.0mm, the length is 20m, the volume is 15.7mL, and the reaction temperature is 20 ℃; the flow rate of material I was 5.0mL/min, the flow rate of material II was 2.5mL/min, and the reaction residence time was 2.1 min. And pumping a material III into the reaction tank to be mixed with the reaction liquid, and conveying the mixture to the micro-flow field reaction module 2 for reaction after mixing. Wherein the inner diameter of the pipeline of the micro-flow field reaction module 2 is 1.0mm, the length is 20m, the volume is 15.7mL, and the reaction temperature is 20 ℃; the flow rate of the material III was 4.0mL/min, reaction residence time 1.4 min. Collecting reaction effluent in a collecting module, distilling under reduced pressure to remove an organic solvent, cooling at 0 ℃, filtering and separating to obtain 0.63g of a target product 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan, wherein the conversion rate of the raw material is 80 percent, and the yield is 50 percent.

Example 4

Weighing 1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximino furazan (AAOF), respectively adding 14mL of water and 6mL of concentrated hydrochloric acid (37%), fully stirring and dissolving to obtain a material I, sucking by using a syringe, and placing on a syringe pump; 0.69g NaNO was weighed₂(10mmol,1.0equiv) is dissolved by a proper amount of distilled water to prepare 10mL solution which is used as a material II, and the material II is sucked by a syringe and then is placed on a syringe pump; preparing 0.3mol/L of Na₂CO₃16mL of the solution was used as feed III, which was aspirated with a syringe and placed on a syringe pump. And simultaneously pumping the material I and the material II into the feeding pump, mixing and conveying the mixture to the micro-flow field reaction module 1 for reaction. Wherein the inner diameter of the microchannel reactor A is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 20 ℃; the flow rate of material I was 4.0mL/min, the flow rate of material II was 2.0mL/min, and the reaction residence time was 2.9 min. And pumping a material III into the reaction tank to be mixed with the reaction liquid, and conveying the mixture to the micro-flow field reaction module 2 for reaction after mixing. Wherein the inner diameter of a pipeline of the micro-channel reactor 1 is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is set to be 20 ℃; the flow rate of material III was 3.2mL/min and the reaction residence time was 1.9 min. Collecting reaction effluent, distilling under reduced pressure to remove organic solvent, cooling at 0 deg.C, filtering and separating to obtain 0.76g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with a raw material conversion rate of 90% and a yield of 60%.

Example 5

1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximoyl furazan (AAOF) is weighed and added into 14mL of water and 6mL of concentrated hydrochloric acid (37%) to be dissolved to obtain a material I; 0.69g NaNO was weighed₂(10mmol,1.0equiv) was added to water to make 10mL solution as feed II; 0.3mol/L of Na is measured₂CO₃16mL of solution was used as feed III. The material I and the material II are simultaneously pumped into the feeding pump and are mixed and then conveyed to a micro-pumpThe reaction is carried out in the channel reactor A. Wherein the inner diameter of the microchannel reactor A is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 20 ℃; the flow rate of material I was 2.5mL/min, the flow rate of material II was 1.25mL/min, and the reaction residence time was 4.7 min. And pumping a material III into the reactor to be mixed with the reaction liquid, and conveying the mixture to a microchannel reactor B for reaction after mixing. Wherein the inner diameter of the micro-channel reactor B is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 20 ℃; the flow rate of the material III was 2.0mL/min, and the reaction residence time was 3.1 min. Collecting reaction effluent, distilling under reduced pressure to remove organic solvent, cooling at 0 deg.C, filtering and separating to obtain 0.86g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with raw material conversion rate of 95% and yield of 68%.

Example 6

1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximoyl furazan (AAOF) is weighed and added into 14mL of water and 6mL of concentrated hydrochloric acid (37%) to be dissolved to obtain a material I; 0.69g NaNO was weighed₂(10mmol,1.0equiv) was added to water to make 10mL solution as feed II; 0.3mol/L of Na is measured₂CO₃16mL of solution was used as feed III. And simultaneously pumping the material I and the material II into the feed pump, mixing and conveying the mixture to the microchannel reactor A for reaction. Wherein the inner diameter of the microchannel reactor A is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 20 ℃; the flow rate of material I was 2.0mL/min, the flow rate of material II was 1.0mL/min, and the reaction residence time was 5.9 min. And pumping a material III into the reactor to be mixed with the reaction liquid, and conveying the mixture to a microchannel reactor B for reaction after mixing. Wherein the inner diameter of the micro-channel reactor B is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 20 ℃; the flow rate of material III was 1.6mL/min and the reaction residence time was 3.8 min. Collecting reaction effluent, distilling under reduced pressure to remove organic solvent, cooling at 0 deg.C, filtering and separating to obtain 0.91g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with a raw material conversion rate of 98% and a yield of 72%.

Example 7

1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximoyl furazan (AAOF) is weighed and added into 14mL of water and 6mL of concentrated hydrochloric acid (37%) to be dissolved to obtain a material I; 0.69g of Na was weighedNO₂(10mmol,1.0equiv) was added to water to make 10mL solution as feed II; 0.3mol/L of Na is measured₂CO₃16mL of solution was used as feed III. And simultaneously pumping the material I and the material II into the feed pump, mixing and conveying the mixture to the microchannel reactor A for reaction. Wherein the inner diameter of the microchannel reactor A is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 10 ℃; the flow rate of material I was 2.0mL/min, the flow rate of material II was 1.0mL/min, and the reaction residence time was 5.9 min. And pumping a material III into the reactor to be mixed with the reaction liquid, and conveying the mixture to a microchannel reactor B for reaction after mixing. Wherein the inner diameter of the micro-channel reactor B is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 20 ℃; the flow rate of material III was 1.6mL/min and the reaction residence time was 3.8 min. Collecting reaction effluent, distilling under reduced pressure to remove organic solvent, cooling at 0 deg.C, filtering and separating to obtain 0.96g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with raw material conversion rate of 98% and yield of 76%.

Example 8

1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximoyl furazan (AAOF) is weighed and added into 14mL of water and 6mL of concentrated hydrochloric acid (37%) to be dissolved to obtain a material I; 0.69g NaNO was weighed₂(10mmol,1.0equiv) was added to water to make 10mL solution as feed II; 0.3mol/L of Na is measured₂CO₃16mL of solution was used as feed III. And simultaneously pumping the material I and the material II into the feed pump, mixing and conveying the mixture to the microchannel reactor A for reaction. Wherein the inner diameter of the microchannel reactor A is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 0 ℃; the flow rate of material I was 2.0mL/min, the flow rate of material II was 1.0mL/min, and the reaction residence time was 5.9 min. And pumping a material III into the reactor to be mixed with the reaction liquid, and conveying the mixture to a microchannel reactor B for reaction after mixing. Wherein the inner diameter of the micro-channel reactor B is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 20 ℃; the flow rate of material III was 1.6mL/min and the reaction residence time was 3.8 min. Collecting reaction effluent, distilling under reduced pressure to remove organic solvent, cooling at 0 deg.C, filtering and separating to obtain 0.88g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with raw material conversion rate of 93% and yield of 70%.

Example 9

1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximoyl furazan (AAOF) is weighed and added into 14mL of water and 6mL of concentrated hydrochloric acid (37%) to be dissolved to obtain a material I; 0.69g NaNO was weighed₂(10mmol,1.0equiv) was added to water to make 10mL solution as feed II; 0.3mol/L of Na is measured₂CO₃16mL of solution was used as feed III. And simultaneously pumping the material I and the material II into the feed pump, mixing and conveying the mixture to the microchannel reactor A for reaction. Wherein the inner diameter of the microchannel reactor A is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 10 ℃; the flow rate of material I was 2.0mL/min, the flow rate of material II was 1.0mL/min, and the reaction residence time was 5.9 min. And pumping a material III into the reactor to be mixed with the reaction liquid, and conveying the mixture to a microchannel reactor B for reaction after mixing. Wherein the inner diameter of the micro-channel reactor B is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 10 ℃; the flow rate of material III was 1.6mL/min and the reaction residence time was 3.8 min. Collecting reaction effluent, distilling under reduced pressure to remove organic solvent, cooling at 0 deg.C, filtering and separating to obtain 0.92g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with raw material conversion rate of 96% and yield of 73%.

Example 10

1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximoyl furazan (AAOF) is weighed and added into 14mL of water and 6mL of concentrated hydrochloric acid (37%) to be dissolved to obtain a material I; 0.69g NaNO was weighed₂(10mmol,1.0equiv) was added to water to make 10mL solution as feed II; 0.3mol/L of Na is measured₂CO₃16mL of solution was used as feed III. And simultaneously pumping the material I and the material II into the feed pump, mixing and conveying the mixture to the microchannel reactor A for reaction. Wherein the inner diameter of the microchannel reactor A is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 10 ℃; the flow rate of material I was 2.0mL/min, the flow rate of material II was 1.0mL/min, and the reaction residence time was 5.9 min. And pumping a material III into the reactor to be mixed with the reaction liquid, and conveying the mixture to a microchannel reactor B for reaction after mixing. Wherein the inner diameter of the micro-channel reactor B is 1.5mm, the length is 10m, the volume is 17.7mL, and the reaction temperature is 30 ℃; the flow rate of the material III is 1.6mL/min,the reaction residence time was 3.8 min. Collecting reaction effluent, distilling under reduced pressure to remove organic solvent, cooling at 0 deg.C, filtering and separating to obtain 0.88g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with raw material conversion rate of 92% and yield of 70%.

Comparative example 1

Weighing 1.43g (10mmol,1.0equiv) of 3-amino-4-amidoximoyl furazan (AAOF), adding the mixture into 14mL of water and 6mL of concentrated hydrochloric acid (37%) to dissolve, adding 0.69g of NaNO at 0-2 ℃ after dissolving₂(10mmol,1.0equiv), reacting at 2-4 ℃ for 2h, heating to 20 ℃ for further reaction for 3h, filtering out precipitate, and washing with cold water to obtain 3-amino-4-acyl chloride hydroxyimino furazan (ACOF). Adding the obtained ACOF into 50mL of tetrahydrofuran without further purification, stirring for dissolving, and slowly adding 0.3mol/L Na at 0-3 DEG C₂CO₃The solution was 16mL and the reaction was stirred at less than 20 ℃ for 3 h. The reaction solution was cooled at 0 ℃ and then filtered to separate 0.59g of 3, 4-bis (4 '-aminofurazan-3' -yl) furoxan (DATF), with a raw material conversion of 82% and a yield of 47%.

The beneficial effects obtained by the present invention are illustrated by the following experiments:

1. in order to investigate the influence of the size of the microchannel reactor on the reaction yield, in example 1 (i.e., the flow rate of material I was 5.0mL/min, the flow rate of material II was 2.5mL/min, the flow rate of material III was 4.0mL/min, the reaction temperature was 20 ℃ and 20 ℃ respectively, the inner diameter of the microchannel reactor was 1.5mm, the length was 10m, and the volume was 17.7mL), different microchannel reactors were used, respectively, to investigate the influence of the size of the microchannel reactor on the reaction yield. The specific settings are as follows: example 2 a microchannel reactor with an internal diameter of 2.0mm, a length of 6m and a volume of 18.4mL was used; example 3A microchannel reactor was used having an internal diameter of 1.0mm, a length of 20m and a volume of 15.7 mL. The results are shown in table 1:

TABLE 1 influence of microchannel reactor size on yield

Experimental group	Inner diameter (mm)	Length (m)	Volume (mL)	Yield (%)
					Example 1	1.5	10	17.7	57
Example 2	2.0	6	18.4	52
					Example 3	1.0	20	15.7	46

As can be seen from Table 1, the size of the microchannel reactor has a great influence on the reaction yield, and when the inner diameter of the microchannel reactor is large, the materials are not sufficiently mixed, so that the yield is reduced; when the inner diameter of the microchannel reactor is smaller, the material circulation is not smooth or even blocked, and the yield is also reduced.

2. In order to investigate the influence of the feed flow rate and the residence time on the reaction yield, in example 1 (i.e., the flow rate of material I was 5.0mL/min, the flow rate of material II was 2.5mL/min, the flow rate of material III was 4.0mL/min, and the residence times were 2.4min and 1.5min, respectively), different feed flow rates and residence times were used on the basis thereof, respectively, to investigate the influence of the feed flow rate and the residence time on the reaction yield. The specific settings are as follows: example 4 used feed flow rates of 4.0mL/min, 2.0mL/min, 3.2mL/min, respectively; example 5 used feed flow rates of 2.5mL/min, 1.25mL/min, 2.0mL/min, respectively; example 6 used feed flow rates of 2.0mL/min, 1.0mL/min, 1.6mL/min, respectively. The results are shown in table 2:

TABLE 2 Effect of feed flow Rate and residence time on reaction yield

Experimental group	Material I	Material II	Material III	Residence time	Yield (%)
						Example 1	5.0	2.5	4.0	2.4+1.5	57
Example 4	4.0	2.0	3.2	2.9+1.9	60
						Example 5	2.5	1.25	2.0	4.7+3.1	68
Example 6	2.0	1.0	1.6	5.9+3.8	72

As can be seen from Table 2, when the feeding flow rate is reduced and the reaction residence time is prolonged, the reaction yield is also increased, but the reaction time is too long due to too low flow rate, and the reaction yield is not significantly increased, so the feeding flow rate is set to be 2.0mL/min for material I, 1.0mL/min for material II, 1.6mL/min for material III, and 5.9min and 3.8min for reaction residence time.

3. In order to investigate the influence of temperature on the reaction yield, in example 6 (i.e., the flow rate of material I was 2.0mL/min, the flow rate of material II was 1.0mL/min, the flow rate of material III was 1.6mL/min, the reaction temperatures were 20 ℃ and 20 ℃, the residence times were 5.9min and 3.8min, the inner diameter of the microchannel reactor was 1.5mm, the length was 10m, and the volume was 17.7mL), different reaction temperatures were used, respectively, and the influence of temperature on the reaction yield was investigated. The specific settings are as follows: example 7 reaction temperatures of 10 ℃ and 20 ℃ were used, respectively; example 8 reaction temperatures of 0 ℃ and 20 ℃ were used, respectively; example 9 reaction temperatures of 10 ℃ and 10 ℃ were used, respectively; example 10 reaction temperatures of 10 ℃ and 30 ℃ were used, respectively;

TABLE 3 Effect of temperature on reaction yield

Experimental group	Reaction temperature (. degree.C.) of A	Reaction temperature (. degree.C.)	Yield (%)
				Example 6	20	20	72
Example 7	10	20	76
				Example 8	0	20	70
Example 9	10	10	73
				Example 10	10	30	70

As can be seen from Table 3, the reaction temperature has a great influence on the reaction yield, and the reaction rate is reduced due to too low temperature, which leads to a reduction in yield; when the temperature is too high, the side reaction is increased, and the yield is also reduced, so that the reaction temperature of the microchannel reactor A is set to be 10 ℃, and the reaction temperature of the microchannel reactor A is set to be 10 ℃.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that the invention is not limited thereto, and various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the invention.

Claims

1. a method for continuously preparing 3,4-bis(4'-aminofurazan-3'-base) oxide furazan using a microchannel reactor, is characterized in that, comprises the steps:

(1) The 3-amino-4-amidoxime-based furazan solution and the sodium nitrite aqueous solution were simultaneously pumped into the first micro-mixer in the micro-channel reactor device, and after mixing, passed into the first reaction module for the first reaction ;

(2) While step (1) is carried out, the effluent of the first reaction module and the sodium carbonate solution are simultaneously pumped into the second micro-mixer in the micro-channel reactor device, and after mixing, they are passed into the second reaction module to carry out the first step. The second reaction is to obtain an effluent containing 3,4-bis(4'-aminofurazan-3'-yl)furazan oxide;

Wherein, the pipe diameter of the first reaction module and the second reaction module has an inner diameter of 1.5 mm and a length of 10 m;

Wherein, the reaction temperature of the first reaction is 10-20 °C, and the reaction residence time is 4-6 min;

Wherein, the reaction temperature of the second reaction is 10-30° C., and the reaction residence time is 3-4 min.

2. The method according to claim 1, characterized in that, in step (1), the solvent of the 3-amino-4-amidoximino-furazan solution is a mixed solvent of water and hydrochloric acid, or an organic solvent and mixed solvent of hydrochloric acid.

3. The method according to claim 1, characterized in that, in step (1), in the 3-amino-4-amidoximino-furazan solution, the 3-amino-4-amidoximino-furazan solution The concentration is 0.1~5.0 mol/L.

4 . The method according to claim 1 , wherein, in step (1), the concentration of sodium nitrite in the sodium nitrite aqueous solution is 0.5 to 10.0 mol/L. 5 .

5. The method according to claim 1, characterized in that, in step (1), the pumping rates of the 3-amino-4-amimidoximidofurazan solution and the aqueous sodium nitrite solution are both 0.2 ~10.0 mL/min.

6 . The method according to claim 1 , wherein, in step (2), the solvent of the sodium carbonate solution is a mixed solvent of water and tetrahydrofuran. 7 .

7. The method according to claim 1, characterized in that, in step (2), the concentration of sodium carbonate in the sodium carbonate solution is 0.1 to 1.0 mol/L.

8 . The method according to claim 1 , wherein, in step (2), the pumping rate of the sodium carbonate solution is 0.2 to 10.0 mL/min. 9 .