Methylisothiazolinone production device

Abstract

The utility model belongs to the technical field of chemical production, and discloses a methylisothiazolinone production device which comprises a reaction kettle, a cooler, a centrifugal machine, an extraction kettle, a drying kettle and a distillation kettle which are sequentially communicated through pipelines, valves and pumps, the reaction kettle is provided with a temperature control device, a stirring device, a temperature sensor, a pH sensor and a pressure sensor; a solid material inlet, a liquid material inlet, a gas inlet and a gas outlet are further formed, the solid material inlet is communicated with the sulfur feeding device through a pipeline, the liquid material inlet is respectively communicated with the methylamine aqueous solution metering tank, the acrylic acid metering tank and the sodium hydroxide metering tank through pipelines, and the gas inlet is communicated with the oxygen storage tank through a pipeline. The device is reasonable in design, simple in structure, convenient to operate, high in yield and easy for industrial production.

Description

Technical Field

[0001] This utility model belongs to the field of chemical production technology, specifically relating to a methylisothiazolinone production device. Background Technology

[0002] Isothiazolinones are a novel type of broad-spectrum fungicide, possessing advantages such as high efficiency, broad spectrum, low toxicity, and biodegradability in the environment, making them widely applicable. Methylisothiazolinone, a type of isothiazolinone, is primarily used in industrial fungicides and antifungals, crop disease control, and marine antifouling agents. Currently, methylisothiazolinones (5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one) are prepared by reacting methyl acrylate with sulfides; however, this method is limited to theoretical research, and corresponding industrial-scale production equipment has not been publicly disclosed, severely hindering the market expansion and application of this product. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a methylisothiazolinone production device that overcomes the defects in the prior art. It discloses a process flow for preparing methylisothiazolinone using methyl acrylate, methylamine aqueous solution, and sulfur. The device is reasonably designed, simple in structure, easy to operate, has a high yield, and is easy to industrialize.

[0004] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0005] A methylisothiazolinone production apparatus includes a reaction vessel, a cooler, a centrifuge, an extraction vessel, a drying vessel, and a distillation vessel connected in sequence by pipes, valves, and pumps. The reaction vessel is equipped with a temperature control device, a stirring device, a temperature sensor, a pH sensor, and a pressure sensor. It is also equipped with a solid material inlet, a liquid material inlet, a gas inlet, and a gas outlet. The solid material inlet is connected to a sulfur feeding device via a pipe. The liquid material inlet is connected to a methylamine aqueous solution metering tank, an acrylic acid metering tank, and a sodium hydroxide metering tank via pipes, respectively. The gas inlet is connected to an oxygen storage tank via a pipe.

[0006] Preferably, the reactor is a glass-lined reactor, which is corrosion-resistant.

[0007] Preferably, the gas inlet of the reactor is located at the bottom of the reactor, and the gas outlet is located at the top of the reactor; the solid material inlet and the liquid material inlet are respectively located at the top of the reactor.

[0008] Preferably, the cooler is equipped with a heat exchange device.

[0009] Preferably, the centrifuge is a disc centrifuge.

[0010] Preferably, the extraction vessel is connected to a dichloromethane storage tank via pipes, valves, and a pump.

[0011] Preferably, the drying kettle is equipped with a sodium sulfate inlet, which is connected to a sodium sulfate supply tank via a pipe and a valve.

[0012] Preferably, the distillation vessel is a vacuum distillation vessel.

[0013] Preferably, the reaction vessel, extraction vessel, drying vessel, and distillation vessel are each equipped with a suction hood, which is connected to the exhaust gas treatment system via pipelines. The exhaust gas treatment system includes an acid washing tower, an alkali washing tower, an activated carbon adsorption tower, an exhaust fan, and a chimney. It is used to treat volatile organic compounds (such as methylamine).

[0014] Due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0015] In this invention, methyl acrylate and methylamine undergo a Michael addition reaction in a reactor to generate N-methyl-β-alanine methyl ester, which is then cyclized with sulfur under oxidizing conditions to obtain a reaction solution containing methylisothiazolinone (MIT). The obtained reaction solution is first cooled, and the crystals are centrifuged to remove them. Then, the product methylisothiazolinone is obtained by extraction, drying, and distillation. The yield of methylisothiazolinone obtained by this production process is 75%, and the purity is greater than 98%.

[0016] In summary, this utility model has a reasonable design, simple structure, convenient operation, high yield, and is easy to industrialize. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of this utility model;

[0018] In the diagram, 1 is the reaction vessel; 2 is the cooler; 3 is the centrifuge; 4 is the extraction vessel; 5 is the drying vessel; 6 is the distillation vessel; 7 is the methylamine aqueous solution metering tank; 8 is the acrylic acid metering tank; 9 is the sodium hydroxide metering tank; and 10 is the oxygen storage tank. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0020] Example 1:

[0021] like Figure 1As shown, a methylisothiazolinone production apparatus includes a reaction vessel 1, a cooler 2, a centrifuge 3, an extraction vessel 4, a drying vessel 5, and a distillation vessel 6, which are connected in sequence via pipes (not shown), valves (not shown), and pumps (not shown). The reaction vessel 1 is equipped with a temperature control device (not shown), a stirring device (not shown), a temperature sensor (not shown), a pH sensor (not shown), and a pressure sensor (not shown). It also has a solid material inlet (not shown), a liquid material inlet (not shown), a gas inlet (not shown), and a gas outlet (not shown). The solid material inlet is connected to a sulfur feeding device (not shown) via a pipe. The liquid material inlet is connected to a methylamine aqueous solution metering tank 7, an acrylic acid metering tank 8, and a sodium hydroxide metering tank 9 via pipes, respectively. The gas inlet is connected to an oxygen storage tank 10 via a pipe.

[0022] In actual production, firstly, methyl acrylate is added to reaction vessel 1 and cooled to 0-5℃ (ice-water bath). Then, methylamine aqueous solution is slowly added dropwise at a molar ratio of methyl acrylate to methylamine aqueous solution (40%) of 1:1.1. The excess methylamine is to ensure complete reaction. The dropping rate is controlled to keep the temperature ≤10℃ (to prevent violent exothermic reaction). After the dropping is completed, the temperature is raised to 25-30℃ and the reaction is stirred for 4-6 hours. The pH is maintained at 9-10 (adjusted with NaOH). The consumption of raw materials is monitored by HPLC or TLC to obtain N-methyl-β-alanine methyl ester.

[0023] Then, N-methyl-β-alanine methyl ester and sulfur were mixed at a molar ratio of 1:1.2 for cyclization reaction. Excess sulfur promoted oxidative cyclization. Sulfur powder was added to reaction vessel 1 and stirred until homogeneous. The temperature was raised to 80-90°C, oxygen was introduced, and the reaction was carried out for 6-8 hours. The reaction progress was monitored by GC / MS or HPLC until the intermediate disappeared.

[0024] The obtained reaction solution is transferred to cooler 2 and cooled to below 20°C, causing unreacted sulfur and byproducts to crystallize out. Then, crystalline impurities are removed by centrifuge 3, and the liquid is transferred to extraction vessel 4, where dichloromethane is added for extraction. The resulting organic phase is transferred to drying vessel 5, where anhydrous sodium sulfate is added for drying. The dried reaction solution is then transferred to distillation vessel 6 for distillation (pressure 10-20 mmHg), and the fraction with a boiling point of 120-125°C / 10 mmHg is collected to obtain the methylisothiazolinone (MIT) product.

[0025] Waste gas generated during production is treated by a tail gas treatment system before being discharged, and waste residue is treated as hazardous waste (mainly sulfur residue).

[0026] It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A methylisothiazolinone production apparatus, characterized by: The system includes a reaction vessel, a cooler, a centrifuge, an extraction vessel, a drying vessel, and a distillation vessel, which are connected in sequence via pipes, valves, and pumps. The reaction vessel is equipped with a temperature control device, a stirring device, a temperature sensor, a pH sensor, and a pressure sensor. It also has a solid material inlet, a liquid material inlet, a gas inlet, and a gas outlet. The solid material inlet is connected to a sulfur feeding device via a pipe, the liquid material inlet is connected to a methylamine aqueous solution metering tank, an acrylic acid metering tank, and a sodium hydroxide metering tank via pipes, and the gas inlet is connected to an oxygen storage tank via a pipe.

2. The methylisothiazolinone production apparatus according to claim 1, characterized in that: The gas inlet of the reactor is located at the bottom of the reactor, and the gas outlet is located at the top of the reactor; the solid material inlet and the liquid material inlet are respectively located at the top of the reactor.

3. The methylisothiazolinone production apparatus according to claim 1, characterized in that: The centrifuge is a disc centrifuge.

4. The methylisothiazolinone production apparatus according to claim 1, characterized by: The extraction vessel is connected to the dichloromethane storage tank via pipes, valves, and pumps.

5. The methylisothiazolinone production apparatus according to claim 1, characterized by: The drying kettle is equipped with a sodium sulfate inlet, which is connected to a sodium sulfate supply tank via a pipe and valve.

6. The methylisothiazolinone production apparatus according to claim 1, characterized in that: The distillation vessel is a vacuum distillation vessel.

7. The methylisothiazolinone production apparatus according to claim 1, characterized by: The reaction vessel, extraction vessel, drying vessel, and distillation vessel are each equipped with a suction hood, which is connected to the exhaust gas treatment system via a pipeline.

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