Continuous preparation method for nitrifying sulfentrazone

Abstract

The invention discloses a continuous preparation method for nitration of sulfentrazone, which comprises the following steps: carrying out nitration reaction on raw materials, namely 1-(2, 4-dichlorophenyl)-3-methyl-4-difluoromethyl-1H-1, 2, 4-triazole-5 (4H) ketone, fuming sulfuric acid and fuming nitric acid to obtain a nitrated substance; the continuous preparation method is safe in reaction process, simple to operate, high in product yield and suitable for industrial production, and efficient mixing of materials can be realized through the continuous reaction device, so that the reaction rate can be remarkably increased, and the prepared sulfentrazone nitration intermediate is high in yield and excellent in quality.

Description

Technical Field

[0001] The invention relates to the field of chemical synthesis, and in particular to a continuous preparation method for nitration of sulfentrazone. Background Art

[0002] Sulfonamide is widely used as a safe and effective herbicide and plays an important role in weed control and crop yield increase. The synthesis methods of sulfonamide can be divided into the following methods: sulfonyl chloride method, sulfonic acid method, sulfonic ester method, sulfonamide method and other synthesis methods. Among them, the sulfonyl chloride method, sulfonic acid method and sulfonic ester method are respectively to react aniline key intermediates with other substances to generate sulfonamide. When the aniline key intermediate is synthesized by the 2,4-dichloroaniline method, 2,4-dichloroaniline is used as the starting material, and the aniline key intermediate is obtained by heavy ammonia reaction, cyclization, N-alkylation, nitration and reduction. The nitration reaction is carried out by a nitration reaction device, which is generally a nitration kettle. In the prior art, the raw materials for the nitration reaction are directly added to the nitration kettle, and the raw materials are mixed in the nitration kettle under certain conditions to react. However, the raw materials are not pre-mixed, but mixed and reacted in the nitration kettle. The mixing effect is poor, which affects the completeness of the reaction and has high production costs. It is necessary to provide a continuous nitration reaction device for sulfentrazone to make the reaction more complete, save production costs, and improve safety.

[0003] Patent CN216630774 U discloses a sulfentrazone nitrification reaction device, which relates to the technical field of sulfentrazone synthesis. A 70% pre-reaction can be achieved before the nitrification kettle, and the nitrification reaction is more complete; the waste acid after nitrification in the nitrification kettle can be extracted and recycled into the homogenizer, and the waste acid is reused as a circulating liquid to reduce production costs. The device only achieves the mixing and preliminary reaction of materials, and transports materials through a multi-stage pump. There are many leakage risk points, and part of the material cycle always exists in the reaction system, resulting in an increase in side reactions and a decrease in product quality. In addition, multiple nitrification kettles are required for continued reaction, which is complicated to operate and difficult to control.

[0004] Patent CN108424395B discloses a method for preparing sulfentrazone, wherein sulfentrazone is obtained by reacting triazole sulfone benzene and methyl sulfonate in the presence of a catalyst; the catalyst is a halogenated dimethyl halide, which improves the reaction system, replaces methyl sulfonyl chloride with stable and easy-to-store methyl sulfonate, avoids the use of highly corrosive methyl sulfonyl chloride and triethylamine and pyridine, does not generate salt-containing wastewater, is beneficial to environmental protection, and activates the amino compound with a specific catalyst, resulting in fewer side reactions, less raw material usage, and improved yield and content. The reaction route is long, the reagents are not easy to obtain, the price is expensive, and the actual production cost is high

[0005] Patent CN114276306A discloses a method for synthesizing sulfentrazone, which belongs to the field of organic synthesis technology. The method uses 2,41-dichloroaniline as the starting material, and synthesizes sulfentrazone through nitration, acetyl protection of amino group, nitro reduction, diazotization, diazo reduction, one-step formation of triazolinone ring, triazolinone ring N-difluoromethylation, hydrolysis and deacetylation, mesylation and other reaction steps. The reaction route is long, and the traditional intermittent method is used to carry out dangerous reactions such as nitration and diazotization, which is risky.

[0006] Patent CN112939879A discloses a sulfentrazone continuous nitrification system, including an annular mounting seat fixedly mounted with multiple support columns, each of the annular mounting seats is fixedly connected to a discharge pipe, and each discharge pipe is installed with a valve, the annular mounting seat is a hollow structure connected at both ends, a mounting frame is fixedly mounted on the annular mounting seat, a storage box and a servo motor are fixedly mounted on the mounting frame, and the upper end of the storage box is open, a rotating shaft is fixedly mounted on the driving end of the servo motor, and multiple nitrification boxes are installed on the rotating shaft through two sets of fixed structures. The device has a complex structure and is not easy to control. The material in the system is prone to low reaction yield and poor quality due to uneven mixing.

[0007] In summary, the preparation method of sulfentrazone disclosed in the prior art has the problems of complicated operation, high risk, and unsuitability for industrial production. Summary of the invention

[0008] The object of the present invention is to overcome the deficiencies of the prior art and provide a continuous preparation method of sulfentrazone nitration, wherein a raw material (2), fuming sulfuric acid and fuming nitric acid are used to obtain a nitrated product (1) through a nitration reaction, wherein the raw material (2) is 1-(2,4-dichlorophenyl)-3-methyl-4-difluoromethyl-1H-1,2,4-triazol-5(4H)-one, and the synthesis equation is as follows:

[0009]

[0010] The continuous preparation method comprises the following steps:

[0011] The first step is to add oleum and raw material (2) into a batching kettle in sequence, wherein the weight ratio of oleum to raw material (2) is 0.5 to 5.0:1, stir and dissolve for 3 to 6 hours, and control the temperature at 20 to 25° C., and put the materials into a first group of weighing tanks as the first raw material;

[0012] Step 2: add fuming sulfuric acid and fuming nitric acid into the batching kettle in a weight ratio of 0.5 to 2:1, stir and dissolve for 1 to 3 hours, control the temperature at 30 to 35°C, and add the materials into the second group of weighing tanks as the second raw material;

[0013] Step 3: The first and second raw materials are respectively fed into the dynamic reactor through the feed pump, the reactor temperature is 30-50°C; the flow rate of the first raw material is 0.1-5kg / min, the flow rate of the second raw material is 0.1-5kg / min, and the speed of the dynamic reactor is 0-6000r / min;

[0014] Step 4: After the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction at a reaction temperature of 30-50°C and a residence time of 10-100 minutes;

[0015] Step 5: The product at the outlet of the tubular reactor is quenched and washed to obtain a sulfentrazone intermediate.

[0016] Preferably, the rotation speed of the dynamic reactor is 500-1000 r / min.

[0017] Preferably, the reactor temperature is 30°C; the first raw material flow rate is 1kg / min, the second raw material flow rate is 0.2kg / min, and the dynamic reactor speed is 50-1000r / min; after the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction, and the reaction temperature is 40°C; the residence time is 80min.

[0018] A continuous preparation system for nitration of sulfentrazone, comprising:

[0019] Multiple batching kettles, add oleum and raw material (2) into the batching kettles successively, wherein the weight ratio of oleum to raw material (2) is 0.5-5.0:1, start stirring and dissolving for 3-6 hours, control the temperature at 20-25°C, and put the materials into a first group of weighing tanks as the first raw material;

[0020] Add fuming sulfuric acid and fuming nitric acid into the batching kettle in sequence, wherein the weight ratio of fuming sulfuric acid to fuming nitric acid is 0.5-2:1, stir and dissolve for 1-3 hours, control the temperature at 30-35°C, and add the materials into the second group of weighing tanks as the second raw material;

[0021] A dynamic reactor, wherein the first raw material and the second raw material are respectively fed into the dynamic reactor through a feed pump, the reactor temperature is 30-50° C.; the flow rate of the first raw material is 0.1-5 kg / min, the flow rate of the second raw material is 0.1-5 kg / min, and the speed of the dynamic reactor is 0-6000 r / min;

[0022] Tubular reactor: after the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction, the reaction temperature is 30-50°C; the residence time is 10-100 minutes; the product at the outlet of the tubular reactor is quenched and washed to obtain the sulfentrazone intermediate;

[0023] The raw material (2) is 1-(2,4-dichlorophenyl)-3-methyl-4-difluoromethyl-1H-1,2,4-triazol-5(4H)-one.

[0024] Preferably, there are three batching kettles.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The invention aims at solving the problems existing in the intermittent reaction of the existing sulfentrazone nitration and proposes a continuous preparation method which has the advantages of safe reaction process, simple operation, high product yield and suitability for industrial production. The continuous reaction device can realize efficient mixing between materials, so that the reaction rate can be significantly improved, and the prepared sulfentrazone nitration intermediate has high yield and excellent quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural diagram of the reaction device of the present invention;

[0028] Figure 2 For the inspection of the map;

[0029] Among them: 1 dynamic reactor, 2 tubular reactor, 3 batching tank, 4 feed pump. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] The present invention provides a continuous preparation method of sulfentrazone nitration, which uses a raw material (2), fuming sulfuric acid and fuming nitric acid to obtain a nitrated product (1) through a nitration reaction, wherein the raw material (2) is 1-(2,4-dichlorophenyl)-3-methyl-4-difluoromethyl-1H-1,2,4-triazole-5(4H)-one, and the synthesis equation is as follows:

[0032]

[0033] The continuous preparation method comprises the following steps:

[0034] The first step is to add oleum and raw material (2) into a batching kettle in sequence, wherein the weight ratio of oleum to raw material (2) is 0.5 to 5.0:1, stir and dissolve for 3 to 6 hours, and control the temperature at 20 to 25° C., and put the materials into a first group of weighing tanks as the first raw material;

[0035] Step 2: add fuming sulfuric acid and fuming nitric acid into the batching kettle in a weight ratio of 0.5 to 2:1, stir and dissolve for 1 to 3 hours, control the temperature at 30 to 35°C, and add the materials into the second group of weighing tanks as the second raw material;

[0036] Step 3: The first raw material and the second raw material are respectively fed into the dynamic reactor through a feed pump, and the reactor temperature is 30-50° C.; the flow rate of the first raw material is 0.1-5 kg / min, the flow rate of the second raw material is 0.1-5 kg / min, and the speed of the dynamic reactor is 0-6000 r / min, preferably 500-1000 r / min;

[0037] Step 4: After the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction at a reaction temperature of 30-50°C and a residence time of 10-100 minutes;

[0038] Step 5: The product at the outlet of the tubular reactor is quenched and washed to obtain a sulfentrazone intermediate.

[0039] The raw material (2) is 1-(2,4-dichlorophenyl)-3-methyl-4-difluoromethyl-1H-1,2,4-triazol-5(4H)-one.

[0040] like Figure 1 As shown, the present invention utilizes a continuous reaction device for preparing a sulfentrazone intermediate, comprising: a batching unit, a weighing feed pipeline, and a two-stage reaction unit;

[0041] The batching unit includes a mixed acid batching kettle and a raw material (2) batching kettle, both of which are used in standby mode and in standby mode;

[0042] The weighing feed pipeline includes a weighing tank, a weighing module, and a feed pump. The weighing tanks are placed on the weighing module, with one for backup and one for use. The feed port of the weighing tank is connected to the discharge port of the batching kettle, the discharge port of the weighing tank is connected to the inlet of the feed pump, and the outlet of the feed pump is connected to the inlet of the dynamic reactor. The feed pump is also placed on the weighing module, and is used to input the raw materials into the dynamic reactor.

[0043] The two-stage reaction unit includes a dynamic reactor and a tubular reactor;

[0044] Each reactor section is provided with a feed inlet and a discharge inlet, and the feed inlet of the dynamic reactor is connected to the outlet of the feed pump;

[0045] The feed inlet of the tubular reactor is connected to the discharge outlet of the dynamic reactor.

[0046] Embodiment 1:

[0047] The continuous preparation method comprises the following steps:

[0048] 1. Add fuming sulfuric acid and raw material (2) into the batching kettle, stir and dissolve at a temperature of 20-25°C;

[0049] 2. Add the raw materials fuming sulfuric acid and fuming nitric acid into the batching kettle, stir and dissolve them at a temperature of 30-35°C;

[0050] 3. The first raw material and the second raw material are respectively fed into a dynamic reactor through a feed pump and fully stirred and mixed for reaction. The speed of the dynamic reactor is 0 to 6000 r / min and the reaction temperature is 0 to 60°C;

[0051] 4. After the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction. The reaction temperature is 30-50° C., the total molar ratio of the fuming sulfuric acid, the raw material (2), and the fuming nitric acid is 2.5-6.0:1:1.0-3.0, the flow rate of the first raw material is 0.1-5 kg / min, the flow rate of the second raw material is 0.1-5 kg / min, and the residence time is 10-100 min.

[0052] 5. The product at the outlet of the reaction unit is quenched and washed to obtain the sulfentrazone intermediate.

[0053] According to the above-mentioned continuous preparation method of sulfentrazone intermediate, the material of the reaction unit is selected from Hastelloy alloy.

[0054] Embodiment 2:

[0055] The continuous preparation method comprises the following steps:

[0056] 1. Add oleum and raw material (2) into a batching kettle in sequence, wherein the weight ratio of oleum to raw material (2) is 2.5:1, start stirring to dissolve, control the temperature at 15-35°C, and put the materials into a first group of weighing tanks as the first raw material;

[0057] 2. Add fuming sulfuric acid and fuming nitric acid into the batching kettle in sequence, the weight ratio of fuming sulfuric acid and fuming nitric acid being 1:1, start stirring and dissolving for 1 hour, control the temperature at 15-35°C, and add the materials into the second group of weighing tanks as the second raw material;

[0058] 3. The first raw material and the second raw material are respectively fed into the dynamic reactor through a feed pump, and the reactor temperature is 30°C; the flow rate of the first raw material is 1kg / min, the flow rate of the second raw material is 0.2kg / min, and the speed of the dynamic reactor is 50-1000r / min;

[0059] 4. After the liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction. The reaction temperature is 40°C and the residence time is 80 minutes.

[0060] 5. The product at the outlet of the tubular reactor is quenched and washed to obtain the sulfentrazone intermediate.

[0061] Through the control of parameters 3-5, the final raw material conversion rate and nitrate purity of continuous and intermittent processes can reach the same level, but the speed is greatly improved and the safety is greatly improved.

[0062] Table 1 Comparison of continuous process and batch process

[0063]

[0064] The beneficial effects of the present invention include:

[0065] (1) Dissolving the raw material (2) in nitric acid at low temperature effectively solves the problem of increasing side reactions caused by dissolving directly in mixed acid in intermittent reactions, controls the generation of reaction impurities, and ensures the fluidity of the material.

[0066] (2) Through the combination of high-efficiency dynamic reactor and tubular reactor, the dynamic reactor solves the problem of poor fluidity and uneven mixing caused by high viscosity of materials during the reaction, and the tubular reactor prolongs the reaction time to ensure the reaction yield and quality. Through the combination, the reaction conversion rate and yield can meet the requirements of industrial production at one time, and the reactor volume can be reduced, greatly improving the efficiency.

[0067] (3) By controlling the dynamic reactor and tubular reactor to react at different temperatures, the generation of impurities is effectively controlled, while the reaction time is shortened and the reaction efficiency is improved.

[0068] The nitration reaction rate and product quality have been improved: the use of a dynamic reactor allows the materials to produce an efficient mixing effect, thereby significantly increasing the reaction rate and reducing the reaction time to 0.3 to 1 hour. As the reaction time shortens, the reaction by-products are greatly reduced, resulting in lower product impurities, better quality, and higher yield.

[0069] (2) The production process is safer: The present invention continuously prepares the sulfentrazone intermediate through an automated control system such as automatic batching, automatic feeding and discharging, thereby simplifying complicated operations, reducing human errors, and greatly improving the safety factor.

[0070] (3) The present invention transforms the intermittent reaction of the traditional process into a continuous reaction. After the degree of automation is improved, labor intensity and labor hours can be saved, which is more conducive to industrialization. It can be seen from Table 1 that the quality and yield of the continuous reaction are consistent with those of the intermittent reaction, and the reaction time is shorter.

[0071] (4) The reaction unit of the present invention adopts special materials with good acid resistance and low equipment loss, thus avoiding the problem of conventional reactors being not resistant to corrosion.

[0072] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention. These improvements should also be considered within the scope of protection of the present invention.

Claims

1. A continuous preparation method for nitrification of sulfentrazone, comprising using a raw material (2), fuming sulfuric acid and fuming nitric acid to obtain a nitrated product (1) through a nitration reaction, wherein: The raw material (2) is 1-(2,4-dichlorophenyl)-3-methyl-4-difluoromethyl-1H-1,2,4-triazol-5(4H)-one, and the synthesis equation is as follows: Characterized in that the continuous preparation method comprises the following steps: The first step is to add oleum and raw material (2) into a batching kettle in sequence, wherein the weight ratio of oleum to raw material (2) is 0.5 to 5.0:1, stir and dissolve for 3 to 6 hours, and control the temperature at 20 to 25° C., and put the materials into a first group of weighing tanks as the first raw material; Step 2: add fuming sulfuric acid and fuming nitric acid into the batching kettle in a weight ratio of 0.5 to 2:1, stir and dissolve for 1 to 3 hours, control the temperature at 30 to 35°C, and add the materials into the second group of weighing tanks as the second raw material; Step 3: The first raw material and the second raw material are respectively fed into the dynamic reactor through the feed pump, and the reactor temperature is 30-50° C.; the flow rate of the first raw material is 0.1-5 kg / min, the flow rate of the second raw material is 0.1-5 kg / min, and the speed of the dynamic reactor is 0-6000 r / min; Step 4: After the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction at a reaction temperature of 30-50°C and a residence time of 10-100 minutes; Step 5: The product at the outlet of the tubular reactor is quenched and washed to obtain a sulfentrazone intermediate.

2. The continuous preparation method for nitration of sulfentrazone according to claim 1, characterized in that: The rotation speed of the dynamic reactor is 500-1000 r / min.

3. The continuous preparation method according to claim 1, characterized in that: The first raw material and the second raw material are respectively fed into the dynamic reactor through the feed pump, and the reactor temperature is 30°C; the flow rate of the first raw material is 1kg / min, the flow rate of the second raw material is 0.2kg / min, and the rotation speed of the dynamic reactor is 50-1000r / min; after the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction, and the reaction temperature is 40°C; the residence time is 80min.

4. A continuous preparation system for nitration of sulfentrazone, comprising: Multiple batching kettles, add oleum and raw material (2) into the batching kettles successively, wherein the weight ratio of oleum to raw material (2) is 0.5-5.0:1, start stirring and dissolving for 3-6 hours, control the temperature at 20-25°C, and put the materials into a first group of weighing tanks as the first raw material; Add fuming sulfuric acid and fuming nitric acid into the batching kettle in sequence, wherein the weight ratio of fuming sulfuric acid to fuming nitric acid is 0.5-2:1, stir and dissolve for 1-3 hours, control the temperature at 30-35°C, and add the materials into the second group of weighing tanks as the second raw material; A dynamic reactor, wherein the first raw material and the second raw material are respectively fed into the dynamic reactor through a feed pump, the reactor temperature is 30-50° C.; the flow rate of the first raw material is 0.1-5 kg / min, the flow rate of the second raw material is 0.1-5 kg / min, and the speed of the dynamic reactor is 0-6000 r / min; Tubular reactor: after the feed liquid comes out of the dynamic reactor, it enters the tubular reactor for reaction, the reaction temperature is 30-50°C; the residence time is 10-100 minutes; the product at the outlet of the tubular reactor is quenched and washed to obtain the sulfentrazone intermediate; The raw material (2) is 1-(2,4-dichlorophenyl)-3-methyl-4-difluoromethyl-1H-1,2,4-triazol-5(4H)-one.

5. The continuous preparation system for nitration of sulfentrazone according to claim 4, characterized in that: There are three batching kettles.

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