A method for the fully continuous flow preparation of the energetic intermediate dichloroglyoxime

Abstract

This invention discloses a fully continuous flow method for preparing the energetic intermediate dichloroethylenedioxime, belonging to the field of organic chemical engineering technology. An aqueous solution of glyoxal, an aqueous solution of hydroxylamine hydrochloride, and an aqueous solution of an inorganic base are simultaneously fed into a micromixer ① and a continuous flow reactor ① for a continuous condensation reaction to obtain an ethylenedioxime reaction slurry. An aqueous solution of an inorganic acid and an aqueous solution of sodium hypochlorite are fed into a micromixer ② and a continuous flow reactor ② to generate an aqueous solution of hypochlorous acid. The ethylenedioxime slurry is mixed with an organic solvent in a micromixer ③ and clarified, then mixed with the aqueous solution of hypochlorous acid in a micromixer ④ and flows into the continuous flow reactor ③, where a continuous chlorination reaction is carried out under back pressure to obtain a dichloroethylenedioxime reaction solution. The dichloroethylenedioxime reaction solution is quenched, concentrated, recrystallized, filtered, and dried to obtain solid dichloroethylenedioxime. This fully continuous flow preparation process can be scaled up to increase the liquid holding volume of the microreactor or to build the same microreactor device, promoting industrial production.

Description

Technical Field

[0001] This invention belongs to the field of organic chemical engineering technology, and specifically relates to a method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process. Background Technology

[0002] Dichloroethylenedioxime is an important energetic intermediate with wide applications in the field of energetic materials. With the continuous development of related industries, higher requirements have been put forward for the preparation technology of dichloroethylenedioxime. Its production is mainly due to the increasing demand for it in the field of energetic materials and the urgent desire for efficient, safe and environmentally friendly synthesis routes.

[0003] Currently, there are three main methods for synthesizing dichloroethylenedioxime both domestically and internationally. The first is the chlorine method (US4539405, GB1307223, CN 104276978). This method uses highly toxic chlorine gas as a raw material. Leaks of chlorine during storage, transportation, and use can cause serious damage to human health and the surrounding environment. Furthermore, the amount of chlorine used in the reaction is difficult to control precisely, and the reaction process is highly exothermic, easily leading to localized overheating, making the reaction difficult to control and posing significant safety risks. In addition, chlorine is highly corrosive, requiring high-quality equipment materials. The second is the chlorosuccinimide method (Org. ProcessRes. Dev. 2016, 20, 1686). This method uses N,N-dimethylformamide as a solvent. This solvent forms complex organic wastewater after the reaction, containing numerous difficult-to-degrade harmful substances. Wastewater treatment is cumbersome, requiring significant investment of manpower, resources, and capital, greatly increasing production costs. Moreover, chlorosuccinimide itself is expensive, which undoubtedly further increases production costs, limiting the product's competitiveness in the market due to price factors. Furthermore, heat accumulation occurs during the reaction process; if heat cannot be dissipated effectively and promptly, it may trigger a series of side reactions or even safety accidents, severely restricting the application of this method in large-scale industrial production. Thirdly, there is the hydrochloric acid / hydrogen peroxide method (CN 109232306). This method requires extremely strict control of the pH of the reaction system; even slight deviations in pH can lead to changes in the reaction direction, reduced yield, or increased byproducts. This necessitates high-precision pH measurement and control equipment, making operation complex and increasing equipment costs. Simultaneously, hydrogen peroxide is unstable and prone to decomposition or even explosion during storage and reaction. Especially during scale-up production, the instability and safety hazards of the reaction system are more prominent, greatly limiting its feasibility for large-scale industrial production.

[0004] In summary, all three existing synthesis methods have drawbacks to varying degrees. Developing a new method for synthesizing dichloroethylenedioxime that is safe, environmentally friendly, low-cost, and suitable for large-scale industrial production has become an urgent task. Summary of the Invention

[0005] In view of this, the object of the present invention is to provide a method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This invention discloses a method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process, comprising the following steps:

[0008] S1. Glyoxime aqueous solution, hydroxylamine hydrochloride aqueous solution and inorganic alkali aqueous solution are simultaneously fed into micro mixer ① and continuous flow reactor ① to carry out continuous condensation reaction to obtain glyoxime reaction slurry.

[0009] S2. Inorganic acid aqueous solution and sodium hypochlorite aqueous solution are simultaneously fed into micro mixer ② and continuous flow reactor ② to generate hypochlorous acid aqueous solution online;

[0010] S3. The dioxime slurry is thoroughly mixed with an organic solvent in a micro mixer ③ and dissolved and clarified. Then it is mixed with a hypochlorous acid aqueous solution in a micro mixer ④ and flows into a continuous flow reactor ③. A continuous chlorination reaction is carried out under back pressure to obtain dichlorodioxime reaction solution.

[0011] S4. After quenching, concentrating, recrystallizing, filtering and drying, dichloroethylenedioxime solid is obtained.

[0012] The chemical reaction formula for dichloroethylenedioxime is shown below:

[0013] .

[0014] Further, in step S1, the mass fraction of the glyoxal aqueous solution is 40%; the mass fraction of the hydroxylamine hydrochloride aqueous solution is 10-40%; the mass fraction of the inorganic base aqueous solution is 10-45%; and the inorganic base is any one of lithium carbonate, sodium carbonate, potassium carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium phosphate, or potassium phosphate.

[0015] Further, in step S1, the molar ratio of glyoxal, hydroxylamine hydrochloride, and inorganic base is 1.0:2.0-5.0:2.0-5.0; the reaction temperature in the micro-mixer and continuous flow reactor ① is -5 to 35°C; and the reaction time of the reactants in the continuous flow reactor ① is 0.5 to 60 minutes.

[0016] Further, in step S2, the sodium hypochlorite aqueous solution is a 12% sodium hypochlorite aqueous solution; the inorganic acid aqueous solution has a mass fraction of 5-40%; and the inorganic acid is any one of hydrochloric acid, sulfuric acid, or phosphoric acid.

[0017] Further, in step S2, the reaction temperature in the micro-mixer and continuous flow reactor ② is -5 to 30°C; the reaction time of the reactants in the continuous flow reactor ② is 0.1 to 10 minutes; and the molar ratio of inorganic acid, sodium hypochlorite and glyoxal in step S2 is 3.0 to 8.0: 2.0 to 6.0: 1.0.

[0018] Further, in step S3, the organic solvent is any one or a mixture of two of the following: methanol, ethanol, isopropanol, n-butanol, isobutanol, tert-butanol, tert-amyl alcohol, ethyl acetate, isopropyl acetate, and acetonitrile; the mass ratio of the organic solvent to the glyoxal aqueous solution is 1.0-10.0:1.0.

[0019] Further, in step S3, the reaction temperature in the micro-mixer and the continuous flow reactor ③ is -5 to 40°C; the reaction time of the reactants in the continuous flow reactor ③ is 0.1 to 10 minutes; and the back pressure is 0.2 to 2.0 MPa.

[0020] Further, the continuous flow reactor ① is any one of a dynamic tubular continuous flow reactor, a plate-type oscillating continuous flow reactor, or a static tubular continuous flow reactor; the inner diameter of the channel of the dynamic tubular continuous flow reactor is 5-150 mm; the inner diameter of the channel of the plate-type oscillating continuous flow reactor is 3-40 mm; and the inner diameter of the channel of the static tubular continuous flow reactor is 3-30 mm.

[0021] Both the continuous flow reactor ② and the continuous flow reactor ③ are any one of a microchannel continuous flow reactor, a plate-type oscillating continuous flow reactor, or a static tubular continuous flow reactor; the inner diameter of the channels in the microchannel continuous flow reactor and the plate-type oscillating continuous flow reactor is 0.1-5 mm; and the inner diameter of the channels in the static tubular continuous flow reactor is 0.8-10 mm.

[0022] Furthermore, the micro mixer is any one of a static mixer, a T-type micro mixer, a Y-type micro mixer, a cross-type mixer, a coaxial flow micro mixer, a dynamic continuous stirring mixer, and a flow focusing micro mixer.

[0023] Further, in step S4, the reagent used in the quenching operation is any one of sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium thiosulfate, or sodium dithionite; the solvent used in the recrystallization operation includes one or a mixture of any two of water, methanol, ethanol, isopropanol, dichloromethane, chloroform, 1,2-dichloroethane, ethyl acetate, toluene, and methyl tert-butyl ether.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. The preparation method of the present invention uses continuous flow technology, in which inorganic acid reacts with sodium hypochlorite to continuously generate hypochlorous acid, a chlorinating reagent. This unstable chlorinating reagent hypochlorous acid is generated and consumed immediately. The reaction system is mild, efficient and has no accumulation of unstable intermediates, which can solve the problems of high toxicity, high cost and instability of chlorinating reagents in the prior art.

[0026] 2. The fully continuous flow reaction technology system provided by this invention includes a feed pump, a micro mixer, a continuous flow reactor, a back pressure valve and other equipment connected in sequence. It has excellent mass transfer and heat transfer performance, greatly enhances the mixing between material molecules, greatly shortens the reaction time, improves the reaction efficiency, and reduces the reaction time from several days in traditional batch reactor reaction to a few minutes. At the same time, side reactions are suppressed, which improves the product quality of dichloroethylene oxime.

[0027] 3. This invention enables end-to-end continuous synthesis from raw materials to finished products. The process is continuous and uninterrupted, with a high degree of automation, avoiding external intervention, and high time and space efficiency. It significantly reduces the number of operators and labor intensity, and significantly reduces production costs.

[0028] 4. In this invention, the continuous reactor has a small online liquid holding volume and a low content of unstable intermediate hypochlorous acid generated by inorganic acid and sodium hypochlorite per unit time, which greatly reduces safety risks. In addition, intrinsic safety can be achieved during industrial scale-up production.

[0029] 5. In this invention, the fully continuous flow preparation process has a smaller scale-up effect compared with the traditional batch process. Increasing the liquid holding volume of the microreactor or building the same microreactor device can rapidly promote industrial production.

[0030] Other advantages, objectives, and features of the invention will be set forth in the following description and will be apparent to those skilled in the art in some respects, or may be learned by practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0031] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the following figures are provided for illustration:

[0032] Figure 1 This is a schematic diagram of the process flow of the present invention;

[0033] Figure 2 This is a synthetic route diagram for dichloroethylenedioxime;

[0034] Figure 3 The HPLC chromatogram of dichloroethylenedioxime prepared in Example 1 is shown below.

[0035] Figure 4The 1H NMR spectrum of dichloroethylenedioxime prepared in Example 1;

[0036] Figure 5 The carbon NMR spectrum of dichloroethylenedioxime prepared in Example 1;

[0037] Figure 1 The following are descriptions: 1. Glyoxal aqueous solution feed pump; 2. Hydroxylamine hydrochloride aqueous solution feed pump; 3. Inorganic alkali aqueous solution feed pump; 4. Inorganic acid aqueous solution feed pump; 5. Sodium hypochlorite aqueous solution feed pump; 6. Organic solvent feed pump; 7. Micromixer ①; 9. Micromixer ③; 10. Micromixer ②; 12. Micromixer ④; 8. Continuous flow reactor ①; 11. Continuous flow reactor ②; 13. Continuous flow reactor ③; 14. Back pressure valve; 15. Storage tank. Detailed Implementation

[0038] like Figure 1-5 As shown, this invention discloses a method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process.

[0039] Example 1

[0040] Prepare the following raw materials as required:

[0041] ① Add water (1146.6 g) to hydroxylamine hydrochloride (382.2 g, 5.5 mol, 2.2 eq) to obtain a 25% aqueous solution of hydroxylamine hydrochloride (1528.8 g).

[0042] ② Add water (513.3 g) to sodium hydroxide (220.0 g, 5.5 mol, 2.2 eq) to obtain a 30% sodium hydroxide aqueous solution (733.3 g);

[0043] ③ Add water (449.4g) to 37% concentrated hydrochloric acid (1213.4g, 12.3mol, 4.9eq) to obtain a 27% hydrochloric acid aqueous solution (1662.8g).

[0044] Reaction procedure:

[0045] S1, 40% glyoxime aqueous solution (362.8g, 2.5mol, 1.0eq) is fed through pump 1, 25% hydroxylamine hydrochloride aqueous solution (1528.8g) is fed through pump 2, and 30% sodium hydroxide aqueous solution (733.3g) is fed through pump 3. The molar ratio of glyoxime aqueous solution, hydroxylamine hydrochloride aqueous solution and sodium hydroxide aqueous solution is adjusted to 1.0∶2.2∶2.2. The above materials are mixed in micro mixer ① (cross-shaped mixer, PTFE material) and then conveyed to continuous flow reactor ① (static tubular continuous flow reactor, PTFE material, inner diameter 6.4mm) for continuous condensation reaction. The temperature of micro mixer ① and continuous flow reactor ① is controlled at 5℃. After the reaction is carried out for 20 minutes, glyoxime reaction slurry is obtained.

[0046] S2, 27% hydrochloric acid aqueous solution (1662.8g) is fed through feed pump 4, and 12% sodium hypochlorite aqueous solution (4342.3g) is fed through feed pump 5. The molar ratio of hydrochloric acid, sodium hypochlorite and glyoxal is adjusted to 4.9:2.8:1.0. The above materials are mixed in micro mixer ② (T-type mixer, PTFE material) and then fed into continuous flow reactor ② (static tubular continuous flow reactor, PTFE material, inner diameter 6.4mm) for reaction. The temperature of micro mixer ② and continuous flow reactor ② is controlled at 10℃. After the reaction is carried out for 18s, hypochlorous acid reaction solution is obtained.

[0047] S3, methanol (800g) is mixed with the dichlorodioxime reaction slurry by feed pump 6 in micro mixer ③ (T-type mixer, PTFE material) to dissolve and clarify. Then it is mixed with the hypochlorous acid reaction solution generated online in micro mixer ④ and flows into continuous flow reactor ③ (static tubular reactor, PTFE material, inner diameter 6.4mm) for continuous chlorination reaction. The temperature of continuous flow reactor ③ is controlled at 10℃ and the reaction pressure is controlled at 0.6MPa by back pressure valve. After 1 minute of reaction, dichlorodioxime reaction solution is obtained.

[0048] S4. Add 10% sodium bisulfite aqueous solution (1800g) to the collected dichloroethylene dioxime reaction solution, stir at 25°C for 1 hour, then concentrate under vacuum at 45°C until the flow stops. Add methanol (750g) to the concentrate, heat to reflux, and slowly add water (2250g) at reflux temperature. Then, cool at a rate of 15°C per hour to 0-5°C and stir for 3 hours. After filtration, wash the filter cake with ice water (400g) and dry the filter cake under vacuum at 50°C for 16 hours to obtain dichloroethylene dioxime white solid (361.0g, 2.30mol), with a total yield of 92.0% and a purity of 99.7%.

[0049] Example 2

[0050] The difference between Example 2 and Example 1 is that the organic solvent in this example is isopropanol, and the mass ratio of isopropanol to glyoxime aqueous solution is adjusted to 4.0:1.0 by organic solvent feed pump 6 to obtain dichloroethylene dioxime white solid (342.6g, 2.18mol), with a total yield of 87.2% and a purity of 98.2%.

[0051] Example 3

[0052] The difference between Example 3 and Example 1 is that the organic solvent in this example is isobutanol, and the mass ratio of isobutanol to glyoxime aqueous solution is adjusted to 6.0:1.0 by organic solvent feed pump 6 to obtain dichloroethylene dioxime white solid (356.5g, 2.27mol), with a total yield of 90.8% and a purity of 99.3%.

[0053] Example 4

[0054] The difference between Example 4 and Example 2 is that in this example, the continuous flow reactor ① is a dynamic tubular continuous flow reactor (Hastelloy alloy material, inner diameter 10mm), and the continuous flow reactors ① and ② are microchannel continuous flow reactors (silicon carbide material, inner diameter 4mm), yielding dichloroethylene dioxime white solid (378.3g, 2.41mol), with a total yield of 96.4% and a purity of 99.6%.

[0055] Example 5

[0056] The difference between Example 5 and Example 3 is that the concentration of hydroxylamine hydrochloride solution in this example is 35%, and the concentration of sodium hydroxide solution is 40%, yielding dichloroethylene dioxime white solid (331.2 g, 2.11 mol), with a total yield of 84.4% and a purity of 97.6%.

[0057] Example 6

[0058] The difference between Example 6 and Example 5 is that in this example, the flow rates of 40% glyoxime aqueous solution (362.8 g, 2.5 mol, 1.0 eq) are adjusted by feed pump 1, 25% hydroxylamine hydrochloride aqueous solution (1390.0 g) is adjusted by feed pump 2, and 30% sodium hydroxide aqueous solution (500 g) is adjusted by feed pump 3, so that the molar ratio of glyoxime, hydroxylamine hydrochloride and sodium hydroxide is 1:2.0:1.5, and dichloroethylenedioxime white solid (302.9 g, 1.93 mol) is obtained, with a total yield of 77.2% and a purity of 92.3%.

[0059] Example 7

[0060] The difference between Example 7 and Example 3 is that the temperature of the micro-mixer 7 and the continuous flow reactor ① is controlled at 0°C and the reaction time is 30 minutes, yielding dichloroethylene dioxime white solid (368.9 g, 2.35 mol), with a total yield of 94.0% and a purity of 98.5%.

[0061] Example 8

[0062] The difference between Example 8 and Example 1 is that the inorganic acid used in this example is sulfuric acid (preparation: 600g of 98% concentrated sulfuric acid is dissolved in 2340g of water to obtain a 20% sulfuric acid aqueous solution). The flow rate of the 20% sulfuric acid aqueous solution is adjusted by feed pump 4 and the flow rate of the 12% sodium hypochlorite aqueous solution is adjusted by feed pump 5 to make the molar ratio of sulfuric acid, sodium hypochlorite and glyoxal 2.4∶2.8∶1.0, to obtain dichloroglyoxime white solid (351.6g, 2.24mol), with a total yield of 89.6% and a purity of 97.2%.

[0063] Example 9

[0064] The difference between Example 9 and Example 1 is that the inorganic acid used in this example is phosphoric acid (preparation: 460g of 85% phosphoric acid dissolved in 1494.4g of water to obtain a 20% phosphoric acid aqueous solution). The flow rate of the 20% phosphoric acid aqueous solution is adjusted by feed pump 4 and the flow rate of the 12% sodium hypochlorite aqueous solution is adjusted by feed pump 5 to make the molar ratio of phosphoric acid, sodium hypochlorite and glyoxal 2.0∶2.8∶1.0, so as to obtain dichloroglyoxime white solid (337.5g, 2.15mol), with a total yield of 86.0% and a purity of 95.1%.

[0065] Example 10

[0066] The difference between Example 10 and Example 2 is that the inorganic alkali aqueous solution used in this example is a 30% potassium hydroxide aqueous solution (5.75 mol, 2.3 eq, 322.6 g potassium hydroxide dissolved in 752.7 g water). By adjusting the glyoxime aqueous solution feed pump 1, the hydroxylamine hydrochloride aqueous solution feed pump 2, and the inorganic alkali aqueous solution feed pump 3, the molar ratio of glyoxime, hydroxylamine hydrochloride, and potassium hydroxide is made to be 1:2.3:2.3, resulting in a white solid of dichloroethylenedioxime (359.4 g, 2.29 mol), with a total yield of 91.6% and a purity of 98.6%.

[0067] Example 11

[0068] The difference between Example 11 and Example 10 is that in this example, micro mixers ①, ②, ③ and ④ are all static mixers, yielding dichloroethylene dioxime white solid (362.6 g, 2.31 mol), with a total yield of 92.4% and a purity of 99.3%.

[0069] Example 12

[0070] The difference between Example 12 and Example 2 is that the micro mixers ①, ②, ③ and ④ in this example are all dynamic continuous stirring mixers, yielding dichloroethylene dioxime white solid (362.6 g, 2.31 mol), with a total yield of 92.4% and a purity of 99.2%.

[0071] Example 13

[0072] The only difference between Example 13 and Example 1 is that the temperature of the micromixer 10 and the continuous flow reactor ② is controlled at 20°C and the reaction time is 0.4 minutes to obtain dichloroethylene dioxime white solid (350.4 g, 2.23 mol), with a total yield of 89.3% and a purity of 96.7%.

[0073] Example 14

[0074] The difference between Example 14 and Example 1 is that the temperature of the micro-mixer ② and the continuous flow reactor ③ in this example is controlled at 15°C, and the reaction is carried out for 1.3 minutes to obtain dichloroethylene dioxime white solid (365.7g, 2.33mol), with a total yield of 93.2% and a purity of 97.7%.

[0075] Example 15

[0076] The difference between Example 15 and Example 5 is that, in this example, the flow rates of the 20% hydrochloric acid aqueous solution (1374.4 g) and the 12% sodium hypochlorite aqueous solution (2323.3 g, 3.75 mol, 1.5 eq) were adjusted by the inorganic acid aqueous solution feed pump 4, the sodium hypochlorite aqueous solution feed pump 5, and the organic solvent feed pump 6, so that the molar ratio of hydrochloric acid, sodium hypochlorite, and glyoxime was 3.0:1.5:1.0, yielding a white solid of dichloroethylenedioxime (327.2 g, 2.08 mol), with a total yield of 83.4% and a purity of 93.7%.

[0077] Example 16

[0078] The difference between Example 16 and Example 1 is that, in this example, the flow rate ratio of 20% hydrochloric acid aqueous solution (2244.8g) and 12% sodium hypochlorite aqueous solution (2323.3g, 3.75mol, 1.5eq) was adjusted by using inorganic acid aqueous solution feed pump 4 and sodium hypochlorite aqueous solution feed pump 5 to make the molar ratio of hydrogen chloride, sodium hypochlorite and glyoxime 4.9∶1.5∶1.0. The temperature of micro-mixer ④ and continuous flow reactor ③ was controlled at 10°C, and the reaction was carried out for 2 minutes to obtain dichloroglyoxime white solid (342.6g, 2.18mol), with a total yield of 87.3% and a purity of 96.7%.

[0079] Example 17

[0080] The difference between Example 17 and Example 3 is that in this example, the flow rate ratio of 20% hydrochloric acid aqueous solution (2244.8g) and 12% sodium hypochlorite aqueous solution (5427.9g, 8.75mol, 3.5eq) was adjusted by the inorganic acid aqueous solution feed pump 4 and the sodium hypochlorite aqueous solution feed pump 5 to make the molar ratio of hydrogen chloride, sodium hypochlorite and glyoxime 4.9∶3.5∶1.0. The temperature of micro-mixer 12 and continuous flow reactor ③ was controlled at 10℃, and the reaction was carried out for 0.8 minutes to obtain dichloroglyoxime white solid (361.8g, 2.30mol), with a total yield of 92.2% and a purity of 98.3%.

[0081] Example 18

[0082] The difference between Example 18 and Example 1 is that, in this example, the flow rate ratio of 20% hydrochloric acid aqueous solution (2748.7g) and 12% sodium hypochlorite aqueous solution (6203.3g, 10.0mol, 4.0eq) was adjusted by using inorganic acid aqueous solution feed pump 4 and sodium hypochlorite aqueous solution feed pump 5 to make the molar ratio of hydrogen chloride, sodium hypochlorite and glyoxime 6.0∶4.0∶1.0, resulting in a white solid of dichloroglyoxime (291.54g, 1.86mol), with a total yield of 74.3% and a purity of 84.2%.

[0083] Example 19

[0084] The difference between Example 19 and Example 5 is that the temperature in the continuous flow reactor ② is controlled at 30°C and the reaction time is 0.5 minutes, yielding dichloroethylene dioxime white solid (359.4 g, 2.29 mol), with a total yield of 91.6% and a purity of 99.2%.

[0085] Example 20

[0086] The difference between Example 20 and Example 5 is that the temperature in the continuous flow reactor ② was controlled at 10°C; the reaction time was 1.2 minutes, yielding a white solid of dichloroethylene dioxime (367.28 g, 2.34 mol), with a total yield of 93.6% and a purity of 99.5%.

[0087] To demonstrate the superiority of the present invention, Comparative Example 1 is provided herein.

[0088] Comparative Example 1

[0089] Stir-fry synthesis of S1 and dioxime (II)

[0090] A 40% glyoxal aqueous solution (365.7 g, 2.52 mol, 1.0 eq) and hydroxylamine hydrochloride (350.56 g, 5.04 mol, 2.0 eq) were placed in a round-bottom flask and cooled to -10°C. Then, a 40% sodium hydroxide aqueous solution (504.5 g, 5.05 mol, 2.0 eq) was slowly added dropwise, with the temperature of the reaction system not exceeding 15°C during the addition process.

[0091] After the addition was complete, the reaction solution was allowed to continue reacting at 0-5℃ for 3 hours. After the reaction was confirmed to be complete by liquid chromatography, the mixture was filtered, and the filter cake was washed with ice water (366.0 g) to obtain wet glyoxime. The wet glyoxime was then vacuum dried at 60℃ for 16 hours to obtain dry glyoxime (188.5 g, 2.14 mol) as a white solid, with a yield of 85% and an HPLC purity of 98.3%.

[0092] Stir-fry synthesis of S2 and dichloroethylenedioxime (I)

[0093] Ethylene dioxime (22.0 g, 0.25 mol, 1.0 eq) and methanol (130.0 mL) were placed in a three-necked round-bottom flask. 36% hydrochloric acid aqueous solution (102.0 mL, 1.22 mol, 4.9 eq) was added. Under ice bath conditions, 12% sodium hypochlorite aqueous solution (434.2 g, 0.70 mol, 2.8 eq) was slowly added dropwise to the oxime hydrochloric acid solution, maintaining the reaction temperature at 0–5 °C during the addition. After the addition was complete, the mixture was stirred for 6 hours at 0–5 °C. After HPLC analysis confirmed the reaction was complete, 10% sodium bisulfite aqueous solution (100.0 g) was added, and the mixture was stirred at 25 °C for 1 hour.

[0094] The above reaction solution was concentrated under vacuum at 45°C until the flow stopped. Methanol (75g) was added to the concentrate, and the mixture was heated to reflux. Water (200g) was slowly added at reflux temperature, and then the temperature was lowered to 0-5°C at a rate of 15°C / hour while stirring for 3 hours. The mixture was filtered, and the filter cake was washed with ice water (40g). The filter cake was then dried under vacuum at 50°C for 16 hours to obtain dichloroethylene dioxime white solid (22.0g, 0.14mol), with a yield of 56% and a purity of 90.3%.

[0095] Comparing Embodiment 1 of the present invention with Comparative Example 1, it can be found that:

[0096] (1) Example 1 has higher reaction yield and purity;

[0097] (2) In Example 1, the online liquid holding volume of the hazardous intermediate hypochlorous acid is small, and the heat of reaction generated can be removed in time, making the reaction safer and more controllable;

[0098] (3) Example 1 is continuous production, while Comparative Example 1 is intermittent production. Example 1 has a high degree of automation, which greatly reduces the number of operators and labor intensity, and significantly reduces production costs.

[0099] (4) The total reaction time of Example 1 was 21.3 minutes, while the total reaction time of Comparative Example 1 was 9 hours. Example 1 has higher production efficiency.

[0100] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process, characterized in that: Includes the following steps, S1. Glyoxime aqueous solution, hydroxylamine hydrochloride aqueous solution and inorganic alkali aqueous solution are simultaneously fed into micro mixer ① and continuous flow reactor ① to carry out continuous condensation reaction to obtain glyoxime reaction slurry. S2. Inorganic acid aqueous solution and sodium hypochlorite aqueous solution are simultaneously fed into micro mixer ② and continuous flow reactor ② to generate hypochlorous acid aqueous solution online; S3. The dioxime slurry is thoroughly mixed with an organic solvent in a micro mixer ③ and dissolved and clarified. Then it is mixed with a hypochlorous acid aqueous solution in a micro mixer ④ and flows into a continuous flow reactor ③. A continuous chlorination reaction is carried out under back pressure to obtain dichlorodioxime reaction solution. S4. After quenching, concentrating, recrystallizing, filtering and drying, dichloroethylenedioxime solid is obtained. The chemical reaction formula for dichloroethylenedioxime is shown below: 。 2. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 1, characterized in that: In step S1, the mass fraction of the glyoxal aqueous solution is 40%; the mass fraction of the hydroxylamine hydrochloride aqueous solution is 10-40%; the mass fraction of the inorganic base aqueous solution is 10-45%; and the inorganic base is any one of lithium carbonate, sodium carbonate, potassium carbonate, lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium phosphate, or potassium phosphate.

3. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 2, characterized in that: In step S1, the molar ratio of glyoxal, hydroxylamine hydrochloride, and inorganic base is 1.0:2.0-5.0:2.0-5.0; the reaction temperature in the micro-mixer and continuous flow reactor ① is -5 to 35°C; and the reaction time of the reactants in the continuous flow reactor ① is 0.5 to 60 minutes.

4. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 1, characterized in that: In step S2, the sodium hypochlorite aqueous solution is a 12% sodium hypochlorite aqueous solution; the inorganic acid aqueous solution has a mass fraction of 5-40%; and the inorganic acid is any one of hydrochloric acid, sulfuric acid, or phosphoric acid.

5. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 4, characterized in that: In step S2, the reaction temperature in the micro-mixer and continuous flow reactor ② is -5 to 30°C; the reaction time of the reactants in the continuous flow reactor ② is 0.1 to 10 minutes; the molar ratio of inorganic acid, sodium hypochlorite and glyoxal in step S2 is 3.0 to 8.0: 2.0 to 6.0: 1.

0.

6. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 1, characterized in that: In step S3, the organic solvent is any one or a mixture of two of the following: methanol, ethanol, isopropanol, n-butanol, isobutanol, tert-butanol, tert-amyl alcohol, ethyl acetate, isopropyl acetate, and acetonitrile; the mass ratio of the organic solvent to the glyoxal aqueous solution is 1.0-10.0:1.

0.

7. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 6, characterized in that: In step S3, the reaction temperature in the micro mixer and the continuous flow reactor ③ is -5 to 40°C; the reaction time of the reactants in the continuous flow reactor ③ is 0.1 to 10 minutes; and the back pressure is 0.2 to 2.0 MPa.

8. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 1, characterized in that: The continuous flow reactor ① is any one of a dynamic tubular continuous flow reactor, a plate-type oscillating continuous flow reactor, or a static tubular continuous flow reactor; the inner diameter of the channel of the dynamic tubular continuous flow reactor is 5-150 mm; the inner diameter of the channel of the plate-type oscillating continuous flow reactor is 3-40 mm; and the inner diameter of the channel of the static tubular continuous flow reactor is 3-30 mm. Both the continuous flow reactor ② and the continuous flow reactor ③ are any one of a microchannel continuous flow reactor, a plate-type oscillating continuous flow reactor, or a static tubular continuous flow reactor; the inner diameter of the channels in the microchannel continuous flow reactor and the plate-type oscillating continuous flow reactor is 0.1-5 mm; and the inner diameter of the channels in the static tubular continuous flow reactor is 0.8-10 mm.

9. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 8, characterized in that: The micro mixer is any one of the following: static mixer, T-type micro mixer, Y-type micro mixer, cross-type mixer, coaxial flow micro mixer, dynamic continuous stirring mixer, and flow focusing micro mixer.

10. The method for preparing the energetic intermediate dichloroethylenedioxime using a fully continuous flow process according to claim 1, characterized in that: In step S4, the reagent used in the quenching operation is any one of sodium sulfite, sodium bisulfite, sodium metabisulfite, sodium thiosulfate, or sodium dithionite; the solvent used in the recrystallization operation includes one or a mixture of any two of water, methanol, ethanol, isopropanol, dichloromethane, chloroform, 1,2-dichloroethane, ethyl acetate, toluene, and methyl tert-butyl ether.

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