Method and equipment for continuously producing 1, 2, 4-acid oxygen body

Abstract

The invention provides a method and equipment for continuously producing 1, 2, 4-acid oxygen bodies. The preparation method comprises the following steps: a step of obtaining 1, 2, 4-acid slurry, wherein the 1, 2, 4-acid slurry comprises 1, 2, 4-acid, a catalyst and a solvent; obtaining a sodium nitrite solution; a step of obtaining a bottoming material: in a continuous flow reaction device, mixing the 1, 2, 4-acid slurry with a sodium nitrite solution, and carrying out a diazotization reaction to obtain the bottoming material; and obtaining a continuous reaction product: continuously conveying the 1, 2, 4-acid slurry and a sodium nitrite solution into the continuous flow reaction device for diazotization reaction to obtain the continuous reaction product. According to the method for continuously producing the 1, 2, 4-oxometalate, the pipeline reactor is used as a reactor for producing the 1, 2, 4-oxometalate, so that the liquid holdup is reduced, and the production risk and the operation cost are further reduced.

Description

Technical Field

[0001] The invention relates to a method and equipment for continuously producing 1,2,4-acid oxides, and belongs to the field of dye intermediate production. Background Art

[0002] 1,2,4-acid oxide, also known as 1-diazo-2-naphthol-4-sulfonic acid, is an important dye intermediate and is widely used in the synthesis of acid mordant dyes, azo dyes, and nitro-1,2,4-acid oxides. At present, it is generally obtained by diazotization of 1,2,4-acid (i.e., 1-amino-2-naphthol-4-sulfonic acid). Among them, diazotization generally adopts the intermittent method, which not only has low production efficiency, but also has high reaction liquid holding capacity, which makes the reaction risk higher and increases the operating cost and management cost. Summary of the invention

[0003] Problem that the invention aims to solve

[0004] In view of the problems existing in the existing intermittent process, one of the purposes of the present invention is to provide a method for continuously producing 1,2,4-acid oxide, which not only significantly improves the production efficiency, but also reduces the production risk and production maintenance cost, and has a high economic benefit.

[0005] Furthermore, the present invention also provides a device for continuously producing 1,2,4-acid oxides. The device of the present invention not only improves production efficiency, but also makes production safer and reduces production costs.

[0006] Solutions for solving problems

[0007] The present invention provides a method for continuously producing 1,2,4-acid oxide, which comprises the following steps:

[0008] The step of obtaining a 1,2,4-acid slurry: wherein the 1,2,4-acid slurry comprises 1,2,4-acid, a catalyst and a solvent;

[0009] The step of obtaining a sodium nitrite solution;

[0010] The step of obtaining the primer is as follows: in a continuous flow reaction device, mixing the 1,2,4-acid slurry with a sodium nitrite solution and performing a diazotization reaction to obtain the primer;

[0011] The step of obtaining a continuous reaction product is as follows: continuously conveying the 1,2,4-acid slurry and the sodium nitrite solution to the continuous flow reaction device for diazotization reaction to obtain a continuous reaction product.

[0012] According to the method of the present invention, the catalyst comprises a transition metal salt, preferably, the transition metal salt comprises one or a combination of two or more of ferrous sulfate heptahydrate, cupric sulfate pentahydrate, and manganese sulfate monohydrate; and / or,

[0013] Based on the total mass of the 1,2,4-acid slurry being 100%, the content of the 1,2,4-acid is 15-40%, the content of the solvent is 60-85%, and the content of the catalyst is 0.1-0.5%.

[0014] According to the method of the present invention, the mass fraction of sodium nitrite in the sodium nitrite solution is 25-35%, preferably 27-31%.

[0015] According to the method of the present invention, the step of obtaining the primer comprises: placing the 1,2,4-acid slurry in a continuous flow reaction device and starting the circulation, and then adding a sodium nitrite solution, and continuing the circulation for 20-40 minutes to obtain the primer;

[0016] Preferably, in the primer, the volume ratio of 1,2,4-acid slurry to sodium nitrite solution is 5-20:1.

[0017] According to the method of the present invention, in the step of obtaining the primer, the reaction temperature of the continuous flow reaction device is set at 20-40°C, preferably 30-35°C; the stirring rate of the continuous flow reaction device is 200r / min-300r / min, preferably 240r / min-260r / min;

[0018] More preferably, the continuous flow reaction device is a tubular reactor.

[0019] According to the method of the present invention, in the step of obtaining the continuous reaction product, the feed rate of the 1,2,4-acid slurry is 5-10 L / h, preferably 6-8 L / h; the feed rate of the sodium nitrite solution is 300-1000 ml / h, preferably 500-700 ml / h; and / or,

[0020] In the step of obtaining continuous reaction products, the residence time of the continuous flow reaction device is 20-40 minutes.

[0021] According to the method of the present invention, the preparation method further comprises: subjecting the continuous reaction product to acid precipitation treatment to obtain 1,2,4-acid oxide.

[0022] The present invention also provides an apparatus for implementing the method for continuously producing 1,2,4-acid oxides according to the present invention, which comprises a 1,2,4-acid pulping kettle, a sodium nitrite dissolving kettle and a continuous flow reaction device; wherein,

[0023] The 1,2,4-acid pulping kettle is connected to the continuous flow reaction device;

[0024] The sodium nitrite dissolving kettle is connected to a continuous flow reaction device;

[0025] Optionally, a 1,2,4-acid transfer kettle is further provided between the 1,2,4-acid pulping kettle and the continuous flow reaction device.

[0026] According to the equipment of the present invention, the continuous flow reaction device is a pipeline reactor; preferably, the pipeline reactor comprises a 1,2,4-acid inlet, a sodium nitrite inlet, a stirring device and a reaction liquid outlet; wherein,

[0027] The 1,2,4-acid inlet is connected to the 1,2,4-acid pulping kettle or the 1,2,4-acid transfer kettle.

[0028] The sodium nitrite inlet is connected to the sodium nitrite dissolving kettle;

[0029] Preferably, the continuous flow reaction device is further provided with a jacket, and the jacket is provided with a cooling water outlet and a cooling water inlet;

[0030] More preferably, the continuous flow reaction device is further provided with an external circulation inlet and an external circulation outlet.

[0031] According to the equipment of the present invention, the equipment further comprises an acid precipitation kettle, and the continuous flow reaction device is connected to the acid precipitation kettle.

[0032] Effects of the Invention

[0033] The method for continuously producing 1,2,4-acid oxides of the present invention utilizes a pipeline reactor as a reactor for producing 1,2,4-acid oxides, thereby reducing liquid holdup and further reducing production risks and operating costs.

[0034] Furthermore, the present invention also provides a device for continuously producing 1,2,4-acid oxide. By using the device of the present invention, full-process automated chain control can be achieved to realize continuous production of 1,2,4-acid oxide. The device of the present invention can also accurately control process parameters to ensure product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flow chart of a method for continuously producing 1,2,4-acid oxides of the present invention is shown;

[0036] Figure 2 The present invention shows a flow chart of a device for continuously producing 1,2,4-acid oxide;

[0037] Figure 3 A schematic structural diagram of a tubular reactor of the present invention is shown;

[0038] Description of Reference Numerals

[0039] 1: Continuous reaction device, 2: 1,2,4-acid pulping kettle, 3: Sodium nitrite dissolving kettle,

[0040] 4: 1,2,4-acid transfer kettle, 5: first acid precipitation kettle. 6: second acid precipitation kettle;

[0041] 11: 1,2,4-acid inlet, 12: sodium nitrite inlet, 13: reaction liquid outlet,

[0042] 13: stirring device, 15: jacket, 16: cooling water outlet, 17: cooling water inlet;

[0043] 18: External circulation entrance, 19: External circulation exit. DETAILED DESCRIPTION

[0044] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0045] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0046] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0047] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0048] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0049] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0050] <First aspect>

[0051] like Figure 1 As shown, the first aspect of the present invention provides a method for continuously producing 1,2,4-acid oxide, which comprises the following steps:

[0052] The step of obtaining a 1,2,4-acid slurry: wherein the 1,2,4-acid slurry comprises 1,2,4-acid, a catalyst and a solvent;

[0053] The step of obtaining a sodium nitrite solution;

[0054] The step of obtaining the primer is as follows: in a continuous flow reaction device, mixing the 1,2,4-acid slurry with a sodium nitrite solution and performing a diazotization reaction to obtain the primer;

[0055] The step of obtaining a continuous reaction product is as follows: continuously conveying the 1,2,4-acid slurry and the sodium nitrite solution to the continuous flow reaction device for diazotization reaction to obtain a continuous reaction product.

[0056] The method for continuously producing 1,2,4-acid oxides of the present invention utilizes a pipeline reactor as a reactor for producing 1,2,4-acid oxides, which can reduce the liquid holdup, thereby reducing production risks and operating costs.

[0057] In some specific embodiments, the catalyst comprises a transition metal salt. Among them, the catalytic effect is the transition metal ion in the transition metal salt, such as ferrous ion, cupric ion or manganese ion. In the present invention, it is preferred to use a transition metal sulfate as a catalyst. Transition metal sulfate is inexpensive and less corrosive to equipment, and has lower corrosion requirements on equipment than transition metal chloride.

[0058] Specifically, the transition metal salt may include one or a combination of two or more of ferrous sulfate heptahydrate, copper sulfate pentahydrate, and manganese sulfate monohydrate.

[0059] In some specific embodiments, based on the total mass of the 1,2,4-acid slurry as 100%, the content of the 1,2,4-acid is 15-40%, for example: 17%, 19%, 21%, 23%, 25%, 27%, 29%, 31%, 33%, 35%, 37%, 39%, etc.; the content of the solvent is 60-85%, for example: 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, etc.; the content of the catalyst is 0.1-0.5%, for example: 0.12%, 0.15%, 0.17%, 0.2%, 0.22%, 0.25%, 0.28%, 0.3%, 0.32%, 0.35%, 0.37%, 0.4%, 0.42%, 0.45%, 0.48%, etc.

[0060] Based on fluidity considerations, the fluidity requirements of the materials in the continuous process are relatively high. Therefore, the present invention requires a large amount of solvent to improve stability. Further, considering that the heat generated by the heat exchanger conversion reaction is required in the reaction process of the present invention, it is linked to the heat exchange efficiency of the heat exchanger to ensure that the temperature of the reaction system can be maintained stable during operation. Therefore, in the present invention, based on the total mass of the 1,2,4-acid slurry as 100%, the content of the solvent is 70-85%; the content of 1,2,4-acid is 15-30%, and the content of the catalyst is 0.1-0.3%.

[0061] Specifically, in the present invention, the solvent is water.

[0062] In some specific embodiments, in order to make the reaction proceed better, in the present invention, the mass fraction of sodium nitrite in the sodium nitrite solution is 25-35%, preferably 29-31%, for example: 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, etc. The sodium nitrite solution is an aqueous solution of sodium nitrite.

[0063] In some specific embodiments, the step of obtaining the primer includes: placing the 1,2,4-acid slurry in a continuous flow reaction device and starting the circulation, and then adding sodium nitrite solution, and continuing the circulation for 20-40 minutes to obtain the primer.

[0064] The present invention uses a primer to enable the entire continuous equipment to operate before continuous feeding, and after the equipment and various operating parameters such as temperature are stable, the raw materials are started. Thus, the system can be operated stably. Compared with the use of water, the present invention uses a primer to enable faster continuous discharging, while maintaining the relative stability of the concentration of each raw material in the reaction equipment. It is beneficial to the stability of the product purity during the final continuous discharging.

[0065] Preferably, in the primer, the volume ratio of 1,2,4-acid slurry to sodium nitrite solution is 5-20:1, for example: 6:1, 8:1, 10:1, 12:1, 14:1, 16:1, 18:1, etc.

[0066] In some specific embodiments, in the step of obtaining the primer, the reaction temperature set in the continuous flow reaction device is 20-40°C, preferably 25-35°C, for example: 22°C, 25°C, 27°C, 30°C, 32°C, 33°C, 35°C, 38°C, etc.; the stirring rate of the continuous flow reaction device is 200r / min-300r / min, preferably 240r / min-260r / min, for example: 220r / min, 240r / min, 260r / min, 280r / min, etc. If the reaction temperature set in the continuous flow reaction device is too low, the purity of the reaction product will be lower. Therefore, in the present invention, the reaction temperature set in the continuous flow reaction device can be 25-35°C.

[0067] More preferably, the continuous flow reaction device is a tubular reactor.

[0068] In some specific embodiments, in order to make the reaction proceed continuously, in the step of obtaining continuous reaction products, the feed rate of the 1,2,4-acid slurry is 5-10 L / h, preferably 6-8 L / h, for example: 5.5 L / h, 6 L / h, 6.5 L / h, 7 L / h, 7.5 L / h, 8 L / h, 8.5 L / h, 9 L / h, 9.5 L, etc.; the feed rate of the sodium nitrite solution is 300-1000 ml / h, preferably 500-700 ml / h, for example: 350 ml / h, 400 ml / h, 450 ml / h, 500 ml / h, 550 ml / h, 600 ml / h, 650 ml / h, 700 ml / h, 750 ml / h, 800 ml / h, 850 ml / h, 900 ml / h, 950 ml / h, etc. When the feed rate of the 1,2,4-acid slurry is 5-10 L / h and the feed rate of the sodium nitrite solution is 300-1000 ml / h, the reaction can proceed better.

[0069] Furthermore, in the present invention, in the step of obtaining the continuous reaction product, the residence time of the continuous flow reaction device is 20-40 minutes, for example: 22 minutes, 25 minutes, 28 minutes, 30 minutes, 32 minutes, 35 minutes, 38 minutes, etc.

[0070] Furthermore, in the present invention, the continuous reaction product is subjected to an acid precipitation treatment to obtain a 1,2,4-acid oxide. Specifically, the continuous reaction product can be precipitated by using an acidic substance and hot water.

[0071] Specifically, the acidic substance can be any feasible acidic substance such as hydrochloric acid, sulfuric acid, nitric acid, etc. Specifically, in the present invention, the acidic substance can be sulfuric acid, preferably sulfuric acid with a mass fraction of 20-40%, for example: 22%, 25%, 28%, 30%, 32%, 35%, 38%, etc.

[0072] The present invention does not specifically limit the temperature of the hot water, and hot water of a suitable temperature can be selected as needed. Specifically, the temperature of the hot water is 70-90°C, for example, 72°C, 75°C, 78°C, 80°C, 82°C, 85°C, 88°C, etc.

[0073] Furthermore, before acid precipitation, the continuous reaction product may be heated to 40-45°C, for example, 41°C, 42°C, 43°C, 44°C, 45°C, etc.

[0074] Specifically, the acid precipitation includes overflowing the continuous reaction product into the acid precipitation kettle, starting stirring and heating to 40-45° C., adding 20-40% sulfuric acid and 70-90° C. hot water to precipitate the continuous reaction product, and filtering to obtain 1,2,4-acid oxide.

[0075] Specifically, when the acidic substance is sulfuric acid, the amount of the sulfuric acid used can be 60% to 120% of the mass of the continuous reaction product, for example: 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 105%, 110%, 115% and the like; the amount of the hot water used is 7% to 15% of the mass of the continuous reaction product, for example: 8%, 9%, 10%, 11%, 12%, 13%, 14% and the like.

[0076] <Second Aspect>

[0077] like Figure 2 As shown, the second aspect of the present invention provides an apparatus for the continuous production of 1,2,4-acid oxide according to the method of implementing the first aspect of the present invention, which comprises a 1,2,4-acid pulping kettle 2, a sodium nitrite dissolving kettle 3 and a continuous flow reaction device 1; wherein,

[0078] The 1,2,4-acid pulping kettle 2 is connected to the continuous flow reaction device 1;

[0079] The sodium nitrite dissolving kettle 3 is connected to the continuous flow reaction device 1;

[0080] Optionally, a 1,2,4-acid transfer kettle 4 is further provided between the 1,2,4-acid pulping kettle 2 and the continuous flow reaction device 1 .

[0081] The present invention also provides a device for continuously producing 1,2,4-acid oxide. By using the device of the present invention, full-process automated interlocking control can be achieved to realize continuous production of 1,2,4-acid oxide. The device of the present invention can also accurately control process parameters to ensure product quality.

[0082] In some specific embodiments, such as Figure 3 As shown, the continuous flow reaction device 1 can be a pipeline reactor. The pipeline reactor includes a 1,2,4-acid inlet 11, a sodium nitrite inlet 12, a stirring device 14 and a reaction liquid outlet 13; wherein the 1,2,4-acid inlet 11 is connected to the 1,2,4-acid pulping kettle 12 or the 1,2,4-acid transfer kettle 4, and the sodium nitrite inlet 12 is connected to the sodium nitrite dissolving kettle 3.

[0083] Specifically, the continuous flow reaction device 1 is further provided with a jacket 15, and the jacket 15 is provided with a cooling water outlet 16 and a cooling water inlet 17; by providing the jacket 15, the temperature of the pipeline reactor can be further controlled by introducing cooling water.

[0084] Furthermore, the tubular reactor of the present invention is also provided with an external circulation inlet 18 and an external circulation outlet 19. By providing the external circulation inlet 18 and the external circulation outlet 19, the tubular reactor can be connected to other reactors, and the residence time can be further increased, especially when the reaction time is long.

[0085] Furthermore, the 1,2,4-acid pulping kettle 2 and / or the sodium nitrite dissolving kettle 3 may be provided with a weighing unit to control the amount of 1,2,4-acid and sodium nitrite.

[0086] In some specific embodiments, the equipment further comprises an acid precipitation kettle, and the continuous flow reaction device 1 is connected to the acid precipitation kettle.

[0087] Because diazotization is a continuous reaction, the acid precipitation kettle of the present invention may include a first acid precipitation kettle 5 and a second acid precipitation kettle 6, wherein the reaction solution is first stored in the first acid precipitation kettle 5, and is switched to the second acid precipitation kettle 6 after being full, and the first acid precipitation kettle 5 begins to add hot water and acidic substances to perform acid precipitation operation, and the acid precipitation process can be performed by switching between the first acid precipitation kettle 5 and the second acid precipitation kettle 6. Preferably, the acidic substance may be one or a combination of two or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, etc.; for example: sulfuric acid with a mass fraction of 10-50%, etc.

[0088] Example

[0089] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0090] Example 1

[0091] 30 kg of water was added to the 1,2,4-acid slurry kettle, stirring was started, and then 35 kg of 1,2,4-acid filter cake (solid content 40%) and 0.13 kg of copper sulfate were added. The slurry was continued for 5 hours to obtain 1,2,4-acid slurry, which was temporarily stored in the 1,2,4-acid transfer kettle.

[0092] Add 10 kg of water to the sodium nitrite dissolving kettle, start stirring, then add 4 kg of sodium nitrite, stir until dissolved, and obtain a sodium nitrite solution.

[0093] Into the pipeline reactor, 3L of 1,2,4-acid slurry was pre-injected, stirring and circulation were started, the stirring speed of the pipeline reactor was 250r / min, and the jacket temperature control was turned on at the same time to control the temperature of the 1,2,4-acid slurry to about 32°C. After the temperature stabilized, 230ml of sodium nitrite solution was slowly injected. After injection, the circulation was continued for 30 minutes to obtain a base material.

[0094] Then, the feed valves of the 1,2,4-acid slurry and the sodium nitrite solution of the pipeline reactor were opened at the same time, the feed rate of the 1,2,4-acid slurry was 8L / h, and the feed rate of the sodium nitrite solution was 612ml / h. The residence time was about 30 minutes, and the feed was continuously fed for 5 hours to obtain a continuous reaction product.

[0095] The continuous reaction product overflows into the first acid precipitation kettle, the stirring is turned on and the temperature is raised to about 42°C, 50kg of 30% sulfuric acid by mass and 8kg of 80°C hot water are added to precipitate the continuous reaction product, and the 1,2,4-acid oxide is obtained by filtration.

[0096] Example 2

[0097] 30 kg of water was added to the 1,2,4-acid slurry kettle, stirring was started, and then 35 kg of 1,2,4-acid filter cake (solid content 40%) and 0.13 kg of copper sulfate were added. The slurry was continued for 5 hours to obtain 1,2,4-acid slurry, which was temporarily stored in the 1,2,4-acid transfer kettle.

[0098] Add 10 kg of water to the sodium nitrite dissolving kettle, start stirring, then add 4 kg of sodium nitrite, stir until dissolved, and obtain a sodium nitrite solution.

[0099] Into the pipeline reactor, 3L of 1,2,4-acid slurry was pre-injected, and the circulation was started. The stirring speed of the pipeline reactor was 250r / min. At the same time, the jacket temperature control was turned on to control the temperature of the 1,2,4-acid slurry to about 20°C. After the temperature stabilized, 230ml of sodium nitrite solution was slowly injected. After injection, the circulation was continued for 30 minutes to obtain a base material.

[0100] Then, the feed valves of the 1,2,4-acid slurry and the sodium nitrite solution of the pipeline reactor were opened at the same time, the feed rate of the 1,2,4-acid slurry was 8L / h, and the feed rate of the sodium nitrite solution was 612ml / h. The residence time was about 30 minutes, and the feed was continuously fed for 5 hours to obtain a continuous reaction product.

[0101] The continuous reaction product overflows into the first acid precipitation kettle, which is stirred and heated to about 42°C, and 50 kg of 30% sulfuric acid and 8 kg of 80°C hot water are added to precipitate the continuous reaction product. The 1,2,4-acid oxide is obtained by filtration.

[0102] Example 3

[0103] 30 kg of water was added to the 1,2,4-acid slurry kettle, stirring was started, and then 35 kg of 1,2,4-acid filter cake (solid content 40%) and 0.13 kg of copper sulfate were added. The slurry was continued for 5 hours to obtain 1,2,4-acid slurry, which was temporarily stored in the 1,2,4-acid transfer kettle.

[0104] Add 10 kg of water to the sodium nitrite dissolving kettle, start stirring, then add 4 kg of sodium nitrite, stir until dissolved, and obtain a sodium nitrite solution.

[0105] Into the pipeline reactor, 3L of 1,2,4-acid slurry was pre-injected, stirring and circulation were started, the stirring speed of the pipeline reactor was 250r / min, and the jacket temperature control was turned on at the same time to control the temperature of the 1,2,4-acid slurry to about 32°C. After the temperature stabilized, 230ml of sodium nitrite solution was slowly injected. After injection, the circulation was continued for 30 minutes to obtain a base material.

[0106] Then, the feed valves of the 1,2,4-acid slurry and the sodium nitrite solution of the pipeline reactor were opened at the same time, the feed rate of the 1,2,4-acid slurry was 4L / h, and the feed rate of the sodium nitrite solution was 306ml / h. The residence time was about 60 minutes, and the feed was continuously fed for 10 hours to obtain a continuous reaction product.

[0107] The continuous reaction product overflows into the second acid precipitation kettle, which is stirred and heated to about 42°C, and 50kg of 30% sulfuric acid and 8kg of 80°C hot water are added to precipitate the continuous reaction product. The 1,2,4-acid oxide is obtained by filtration.

[0108] Comparative Example 1

[0109] 30 kg of water was added to the 1,2,4-acid slurry kettle, stirring was started, and then 35 kg of 1,2,4-acid filter cake (solid content 40%) and 0.13 kg of copper sulfate were added. The slurry was continued for 5 hours to obtain 1,2,4-acid slurry, which was temporarily stored in the 1,2,4-acid transfer kettle.

[0110] Add 10 kg of water to the sodium nitrite dissolving kettle, start stirring, then add 4 kg of sodium nitrite, stir until dissolved, and obtain a sodium nitrite solution.

[0111] Into the tubular reactor, 3 L of water was pre-injected and the circulation was started. The stirring speed of the tubular reactor was 250 r / min. At the same time, the jacket temperature control was turned on to control the temperature of the water in the reactor to about 32°C.

[0112] After the temperature stabilized, the feed valves of the 1,2,4-acid slurry and the sodium nitrite solution of the pipeline reactor were opened at the same time, the feed rate of the 1,2,4-acid slurry was 8L / h, and the feed rate of the sodium nitrite solution was 612ml / h. The residence time was about 30 minutes, and the continuous feeding was 5.2 hours to obtain a continuous reaction product.

[0113] The continuous reaction product overflows into the second acid precipitation kettle, which is stirred and heated to about 42°C, and 50kg of 30% sulfuric acid and 8kg of 80°C hot water are added to precipitate the continuous reaction product. The 1,2,4-acid oxide is obtained by filtration.

[0114] Comparative Example 2

[0115] Add 126g water, 148.45g 1,2,4-acid filter cake (solid content is 40.46%) and 0.55g industrial copper sulfate into a 500ml reactor, and stir and slurry until uniform. Heat to 32°C. After the temperature stabilizes, slowly drop 55.57g sodium nitrite aqueous solution (17.27g sodium nitrite and 38.30g water), and control the drop time to about 3 hours. After the drop is completed, keep warm for 1 hour, then add 300g 30% sulfuric acid and 42g 80°C water, and filter after the 1,2,4-acid oxide is completely precipitated to obtain the finished 1,2,4-acid oxide.

[0116] The continuous reaction increases the reaction time from 3 hours to 30 minutes, and the purity, yield and other indicators of the final reaction product are consistent with those of the intermittent process.

[0117] Performance Testing

[0118] Detection method: Liquid chromatography

[0119] Detection instrument: Agilent1220-Agilent high performance liquid chromatograph

[0120] Wavelength: 254

[0121] Column temperature: 40°C

[0122] Solvent: 705 acetonitrile

[0123] Mobile phase: 41% acetonitrile + 0.2% TBAB

[0124] The results are shown in Table 1 below:

[0125] Table 1

[0126]

[0127] As can be seen from Table 1, by using the method of the present invention, the purity of the obtained 1,2,4-acid oxide is higher. Among them, the purity of the intermediate control sample is the purity of the slurry detected during or after the reaction, and the final filter cake purity is the purity of the filter cake obtained after the slurry is acidified and filtered. Since the impurities in the mother liquor water are removed during the acidification and filtration process of the slurry, the detection purity will be improved.

[0128] Compared with Comparative Example 1, Example 1 uses water as a primer at the beginning. Therefore, the purity of the intermediate control sample is relatively low at the beginning. After circulating for a period of time, the primer is formed due to the continuous reaction, and its purity will rise and reach a certain level.

[0129] Compared with Comparative Example 2, Example 1 of the present invention can perform continuous reaction, and the final detected purity is significantly better than that of Comparative Example 2.

[0130] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0131] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for continuously producing 1,2,4-acid oxide, characterized in that: The following steps are involved: The step of obtaining a 1,2,4-acid slurry: wherein the 1,2,4-acid slurry comprises 1,2,4-acid, a catalyst and a solvent; The step of obtaining a sodium nitrite solution; The step of obtaining the primer is as follows: in a continuous flow reaction device, mixing the 1,2,4-acid slurry with a sodium nitrite solution and performing a diazotization reaction to obtain the primer; The step of obtaining the continuous reaction product is as follows: continuously conveying the 1,2,4-acid slurry and the sodium nitrite solution to the continuous flow reaction device for diazotization reaction to obtain the continuous reaction product.

2. The method according to claim 1, characterized in that The catalyst comprises a transition metal salt, preferably, the transition metal salt comprises one or a combination of two or more of ferrous sulfate heptahydrate, cupric sulfate pentahydrate, and manganese sulfate monohydrate; and / or, Based on the total mass of the 1,2,4-acid slurry being 100%, the content of the 1,2,4-acid is 15-40%, the content of the solvent is 60-85%, and the content of the catalyst is 0.1-0.5%.

3. The method according to claim 1 or 2, characterized in that: In the sodium nitrite solution, the mass fraction of sodium nitrite is 25-35%, preferably 27-31%.

4. The method according to any one of claims 1 to 3, characterized in that: The step of obtaining the primer comprises: placing the 1,2,4-acid slurry in a continuous flow reaction device and starting the circulation, then adding a sodium nitrite solution, and continuing the circulation for 20-40 minutes to obtain the primer; Preferably, in the primer, the volume ratio of 1,2,4-acid slurry to sodium nitrite solution is 5-20:

1.

5. The method according to claim 4, characterized in that In the step of obtaining the primer, the reaction temperature of the continuous flow reaction device is set at 20-40°C, preferably 30-35°C; the stirring rate of the continuous flow reaction device is 200r / min-300r / min, preferably 240r / min-260r / min; More preferably, the continuous flow reaction device is a tubular reactor.

6. The method according to any one of claims 1 to 5, characterized in that: In the step of obtaining the continuous reaction product, the feed rate of the 1,2,4-acid slurry is 5-10 L / h, preferably 6-8 L / h; the feed rate of the sodium nitrite solution is 300-1000 ml / h, preferably 500-700 ml / h; and / or, In the step of obtaining continuous reaction products, the residence time of the continuous flow reaction device is 20-40 minutes.

7. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: subjecting the continuous reaction product to acid precipitation treatment to obtain 1,2,4-acid oxide.

8. A device for implementing the method for continuously producing 1,2,4-acid oxide according to any one of claims 1 to 7, characterized in that: It includes a 1,2,4-acid pulping kettle, a sodium nitrite dissolving kettle and a continuous flow reaction device; wherein, The 1,2,4-acid pulping kettle is connected to the continuous flow reaction device; The sodium nitrite dissolving kettle is connected to a continuous flow reaction device; Optionally, a 1,2,4-acid transfer kettle is further provided between the 1,2,4-acid pulping kettle and the continuous flow reaction device.

9. The device according to claim 8, characterized in that The continuous flow reaction device is a pipeline reactor; preferably, the pipeline reactor comprises a 1,2,4-acid inlet, a sodium nitrite inlet, a stirring device and a reaction liquid outlet; wherein, The 1,2,4-acid inlet is connected to the 1,2,4-acid pulping kettle or the 1,2,4-acid transfer kettle. The sodium nitrite inlet is connected to the sodium nitrite dissolving kettle; Preferably, the continuous flow reaction device is further provided with a jacket, and the jacket is provided with a cooling water outlet and a cooling water inlet; More preferably, the continuous flow reaction device is further provided with an external circulation inlet and an external circulation outlet.

10. The device according to claim 8 or 9, characterized in that The equipment also includes an acid precipitation kettle, and the continuous flow reaction device is connected to the acid precipitation kettle.

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