CN113979965B - Continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone - Google Patents
Continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D275/00—Heterocyclic compounds containing 1,2-thiazole or hydrogenated 1,2-thiazole rings
- C07D275/02—Heterocyclic compounds containing 1,2-thiazole or hydrogenated 1,2-thiazole rings not condensed with other rings
- C07D275/03—Heterocyclic compounds containing 1,2-thiazole or hydrogenated 1,2-thiazole rings not condensed with other rings with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
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- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N43/00—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds
- A01N43/72—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with nitrogen atoms and oxygen or sulfur atoms as ring hetero atoms
- A01N43/80—Biocides, pest repellants or attractants, or plant growth regulators containing heterocyclic compounds having rings with nitrogen atoms and oxygen or sulfur atoms as ring hetero atoms five-membered rings with one nitrogen atom and either one oxygen atom or one sulfur atom in positions 1,2
Abstract
The invention relates to a continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone. The method not only can obtain the 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone with high purity, but also has high production yield, and adopts continuous production, the production process is safe and controllable, the energy consumption is reduced, and the production efficiency is improved. In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps: preparing N, N '-dioctyl-3, 3' -dithiodipropionamide and ethyl acetate to form a mixed solution; pumping into a first section of jacketed sleeve type tubular reactor and a second section of jacketed sleeve type tubular reactor, wherein the jackets of the first section of tubular reactor are filled with glycol chilled water, the jackets of the second section of tubular reactor are filled with hot water, the reaction temperature is controlled to be 55-60 ℃, and the materials are mixed and stay in the tubes for 5-10 minutes; after the continuous reaction is finished, the reaction liquid directly enters a thin film evaporator, then methanol is added for recrystallization, and then the powder DCOIT product is obtained through the procedures of cooling centrifugation, leaching and drying.
Description
Technical field:
the invention relates to the technical field of bactericide continuous production, in particular to a continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone.
The background technology is as follows:
the 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone (DCOIT for short) is a novel isothiazolin-ketone bactericide, is mainly used in the fields of marine antifouling paint, metal cutting fluid, wood and the like as a mildew-proof algicide, and has a very wide application range.
Chinese patent CN104072440B discloses a preparation method of DCOIT, which comprises the steps of taking N, N '-dioctyl-3, 3' -dithiodipropionamide as a raw material, mixing with a chlorinated solvent, adding a composite catalyst consisting of metal chloride, thiophene compounds and crown ether compounds, slowly adding a chlorinating agent under the low temperature condition for ring closure chlorination reaction, separating and purifying to obtain DCOIT, wherein the detection purity of the DCOIT in the document reaches more than 98%, and the product yield can reach 65-75%. The preparation method adopted by the method is an intermittent preparation method, the post-treatment steps are numerous, the operation is very complex, a large amount of salt-containing wastewater is generated in the process, and the quality and the reaction yield of the product are not ideal.
Chinese patent CN 110483438A discloses a method for continuous production of 3-isothiazolinone compounds in a pipeline, in which N, N '-dioctyl-3, 3' -dithiodipropionamide, sodium iodide, chlorobenzene and chlorine are mixed and reacted in a pipeline reactor system, and after the reaction is completed, DCOIT product is obtained by post-treatment; firstly, mixing and preheating reaction raw materials in proportion, uniformly mixing a solid-liquid mixture through a static mixer to form slurry, then sending the slurry into a pipeline reactor for reaction, introducing chlorine gas into the pipeline reactor at multiple points, controlling the temperature through a temperature control system, wherein the reaction temperature is 55-60 ℃, and the residence time is 20 minutes; DCOIT content was described as > 98% with a synthesis yield of 82%. The continuous production method has the following defects: the materials need to enter the tubular reactor only by a preheating system and a mixing system, and the operation is complex; sodium iodide does not play any catalytic role in the reaction system; the mixed slurry is simply fed with chlorine at multiple points in a pipeline reactor, and side reactions cannot be inhibited at all.
The invention comprises the following steps:
in view of the above, the invention provides a continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone, which not only can obtain high-purity 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone, but also has high production yield, and adopts continuous production, so that the production process is safe and controllable, the energy consumption is reduced, and the production efficiency is improved.
In order to achieve the above purpose, the invention adopts the following technical scheme: 1. a continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone is characterized in that: the method comprises the following steps:
1) The weight ratio of the N, N '-dioctyl-3, 3' -dithiodipropionamide to the ethyl acetate is 1:1.5 to 2.0 to form mixed solution;
2) Pumping the mixed solution into a first section of sleeve-type tubular reactor with a jacket by a pump, enabling N, N '-dioctyl-3, 3' -dithiodipropyl in the mixed solution to contact with chlorine gas at an inlet of the tubular reactor in proportion, introducing glycol chilled water into the jacket of the first section of tubular reactor, controlling the reaction temperature to be 0-5 ℃, and mixing and staying materials in the tube for 10-15 minutes;
3) The reaction materials enter a second section of sleeve-type tubular reactor with a jacket, N '-dioctyl-3, 3' -dithiodipropyl in the reaction liquid contacts with chlorine at the inlet of the tubular reactor according to the proportion, the jacket of the second section of tubular reactor is filled with hot water, the reaction temperature is controlled to be 55-60 ℃, and the materials are mixed and stay in the tube for 5-10 minutes;
4) After the continuous reaction is finished, the reaction liquid directly enters a thin film evaporator, hydrogen chloride and ethyl acetate are distilled off as light components, heavy components continuously enter a receiving kettle, methanol is added for recrystallization, and then the powdery DCOIT product is obtained through cooling centrifugation, leaching and drying treatment procedures.
Further, the molar ratio of chlorine gas used in step 2) to N, N '-dioctyl-3, 3' -dithiodipropionamide in step 1) is 4.3-4.5:1.
further, the molar ratio of chlorine gas used in step 3) to N, N '-dioctyl-3, 3' -dithiodipropionamide in step 1) is 2.7-3.3:1.
compared with the prior art, the invention has the following advantages and effects:
1) According to the invention, through researching a main and side reaction mechanism, creatively discovers that N, N '-dioctyl-3, 3' -dithiodipropionamide and chlorine gas firstly generate a 5-chloroOIT intermediate by controlling the reaction proportion and the reaction temperature, and then DCOIT is generated by continuous chlorination, so that the generation of polychlorinated byproducts is effectively inhibited, and a DCOIT product with high purity and high yield is obtained, the purity is up to more than 99%, and the whole production yield is up to more than 85%.
2) The invention also effectively realizes the continuous production of DCOIT, has simple operation and easy control of the production process, reduces the energy consumption, improves the production efficiency and simultaneously realizes the safety and the controllability of the production process.
3) In the method, when chlorine is introduced for the first time, the molar ratio of the chlorine to the N, N '-dioctyl-3, 3' -dithiodipropionamide in the step 1) is limited, so that the N, N '-dioctyl-3, 3' -dithiodipropionamide (POA) is converted into an intermediate product 5-chloroOIT as far as possible after chlorination.
4) In the invention, when chlorine is introduced for the second time, the molar ratio of the chlorine to the N, N '-dioctyl-3, 3' -dithiodipropionamide in the step 1) is limited, and the chlorination reaction is completed, and meanwhile, the excessive chlorination is avoided to be a polychlorinated byproduct.
The specific embodiment is as follows:
the present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Examples:
a continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone, which comprises the following steps:
1. the weight ratio of the N, N '-dioctyl-3, 3' -dithiodipropionamide to the ethyl acetate is 1:1.5 to 2.0 to form a mixed solution of two components.
2. Pumping the mixed solution into a first section of jacketed sleeve-type tubular reactor by a pump, wherein the molar ratio of the N, N '-dioctyl-3, 3' -dithiodipropyl to the chlorine in the mixed solution is 4.3-4.5:1 are contacted at the inlet of a tubular reactor, glycol chilled water is introduced into the jacket of the first tubular reactor, the reaction temperature is controlled to be 0-5 ℃, and materials are mixed and stay in the tube for 10-15 minutes.
3. The reaction material enters a second section of jacketed sleeve type tubular reactor, and the molar ratio of N, N '-dioctyl-3, 3' -dithiodipropyl to chlorine in the reaction liquid is 2.7-3.3:1 are contacted at the inlet of the tubular reactor, the jacket of the second tubular reactor is filled with hot water, the reaction temperature is controlled to be 55-60 ℃, and the materials are mixed and stay in the tube for 5-10 minutes.
4. After the continuous reaction is finished, the reaction liquid directly enters a thin film evaporator, hydrogen chloride and ethyl acetate are distilled off as light components, heavy components continuously enter a receiving kettle, methanol is added for recrystallization after a certain amount of heavy components is reached, and then the powdery DCOIT product is obtained through cooling centrifugation, leaching and drying treatment procedures.
The DCOT continuous production uses a special tubular reactor, the tubular reactor is divided into two sections, each section is provided with jackets with different mediums, the first section is a low-temperature chlorination section, the jackets of the reactor are filled with glycol chilled water with the temperature controlled at about minus 10 ℃, the second section is a high-temperature chlorination section, and the jackets of the reactor are filled with hot water with the temperature of 50 ℃; the porous baffle plate is arranged in the tubular reactor, so that the mass transfer and heat transfer processes can be effectively enhanced.
Chlorine is introduced in two parts, wherein the first part is introduced at the inlet of the first-stage tubular reactor at multiple points, and the second part is introduced at the inlet of the second-stage tubular reactor at multiple points.
N, N '-dioctyl-3, 3' -dithiodipropionamide and ethyl acetate at 100:200 weight ratio, uniformly mixing, controlling a certain flow rate by a pump, conveying into a first section of tubular reactor, introducing chlorine gas into the inlet of the tubular reactor, and controlling the introducing speed of the chlorine gas, wherein the chlorine gas is as follows: n, N '-dioctyl-3, 3' -dithiodipropionamide (molar ratio) =4.3 to 4.5:1, chloridizing at 0-5 deg.C for 10-15 min.
The first stage chlorination reaction liquid enters a second stage tubular reactor, chlorine gas is introduced into the inlet of the tubular reactor, the introduction speed of the chlorine gas is controlled, and the chlorine gas is partially introduced: n, N '-dioctyl-3, 3' -dithiodipropionamide (molar ratio) =2.7 to 3.2:1, the jacket of the second-stage tubular reactor is filled with hot water at 50 ℃, the exothermic temperature of the reaction is utilized for controlling the temperature to 55-60 ℃ in the second stage chlorination, and the materials are mixed and stay in the tube for 5-10 minutes.
And directly feeding the second-stage chlorination reaction liquid into a thin film evaporator to remove ethyl acetate and hydrogen chloride by decompression, slightly cooling the heavy components to 50-55 ℃, adding methanol for recrystallization, and carrying out procedures such as cooling centrifugation, washing, drying and the like to obtain DCOIT powdery solid with the content of 99%, wherein the continuous production yield is 87%.
The distilled ethyl acetate is directly recycled to the next batch of continuous production, and the methanol mother liquor obtained by centrifugation and the leacheate are combined and then are subjected to simple distillation to recover methanol for recycling to the next batch of recrystallization operation.
The hydrogen chloride separated in the process of the invention is removed from the hydrogen chloride absorption system.
The reaction process of N, N '-dioctyl-3, 3' -dithiodipropionamide and chlorine gas to generate DCOIT is as follows:
n, N '-dioctyl-3, 3' -dithiodipropionamide reacts with chlorine to firstly generate a mixture of 2-octyl-4-isothiazolin-3-ketone (OIT for short), 4-chloroOIT and 5-chloroOIT, and then the mixture is continuously chlorinated to obtain a target product DCOIT.
The main side reaction in the chlorination process is a series of side reactions, polychlorinated byproducts are generated, and the reaction duration is as follows:
the key to improving the quality and synthesis yield of DCOIT is how to suppress the production of polychlorinated byproducts.
Through a large number of experiments, the generation of polychlorinated byproducts is closely related to the generation of 4-chloroIT in a reaction system, and the reaction process is as follows:
experiments show that the selectivity in the process of continuously chlorinating 4-chloroOIT to generate DCOIT is very poor, a large amount of polychlorinated byproducts are generated in the reaction process, and the 4-OIT can be directly chlorinated to generate polychlorinated byproducts without generating DCOIT.
The reaction of N, N '-dioctyl-3, 3' -dithiodipropionamide and chlorine firstly generates 5-chloroOIT, then the chlorination is continued to generate DCOIT, the reaction selectivity is far higher than that of the reaction of firstly generating OIT and 4-chloroOIT, only DCOIT is generated after the chlorination of 5-chloroOIT, and the polychlorinated by-product is mainly generated by the subsequent chlorination of DCOIT, wherein the reaction process is as follows:
studies on the chlorination process show that the chloridization synthesis of DCOIT needs to be controlled in sections, and the generation amount of 5-chloroOIT needs to be increased as much as possible in the early stage of chloridization, which is the key for improving the reaction selectivity and the yield.
A great deal of experimental study is carried out on increasing the production of 5-chloroOIT, and the molar ratio of N, N '-dioctyl-3, 3' -dithiodipropionamide to chlorine in the early stage of chlorination is strictly controlled to be more than 4.0, the optimal range is between 4.3 and 4.5, and the production of 5-chloroOIT in a reaction system is the highest. The inventors have studied the reaction temperature for producing 5-chloroit at the same time, and found that the reaction temperature cannot exceed 10 ℃ when chlorine is introduced, and the optimal range is between 0 and 5 ℃.
As described above, the DCOIT product can continue to undergo a series of side reactions in the chlorination process to generate polychlorinated byproducts, and in order to inhibit the series of side reactions, the DCOIT product is removed from the reaction system in time except that the reaction temperature is not too high and the chlorine ratio is not excessive.
The continuous synthesis can well solve the problems, the continuous operation of the tubular reactor is adopted, the raw materials are continuously fed, the products are continuously discharged, and the occurrence of continuous side reactions taking DCOIT as the raw materials can be effectively avoided.
The above description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention.
Claims (1)
1. A continuous production method of 4, 5-dichloro-2-octyl-4-isothiazolin-3-ketone is characterized in that: the method comprises the following steps:
1) The weight ratio of the N, N '-dioctyl-3, 3' -dithiodipropionamide to the ethyl acetate is 1:1.5 to 2.0 to form mixed solution;
2) Pumping the mixed solution into a first section of sleeve-type tubular reactor with a jacket by a pump, enabling N, N '-dioctyl-3, 3' -dithiodipropyl in the mixed solution to contact with chlorine gas at the inlet of the tubular reactor in proportion, introducing glycol chilled water into the jacket of the first section of tubular reactor, controlling the reaction temperature to be 0-5 ℃, and mixing and staying materials in the tube for 10-15 minutes;
3) The reaction materials enter a second section of sleeve-type tubular reactor with a jacket, N '-dioctyl-3, 3' -dithiodipropyl in the reaction liquid contacts with chlorine at the inlet of the tubular reactor according to the proportion, the jacket of the second section of tubular reactor is filled with hot water, the reaction temperature is controlled to be 55-60 ℃, and the materials are mixed and stay in the tube for 5-10 minutes;
4) After the continuous reaction is finished, the reaction liquid directly enters a thin film evaporator, hydrogen chloride and ethyl acetate are distilled off as light components, heavy components continuously enter a receiving kettle, methanol is added for recrystallization, and then the powdery DCOIT product is obtained through cooling centrifugation, leaching and drying treatment procedures;
the molar ratio of chlorine gas used in step 2) to N, N '-dioctyl-3, 3' -dithiodipropionamide in step 1) is 4.3-4.5:1, a step of;
the molar ratio of chlorine gas used in step 3) to N, N '-dioctyl-3, 3' -dithiodipropionamide used in step 1) is 2.7-3.3:1.
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