阅读说明：本技术 一种高收率、高纯度杀虫剂除虫脲的制备方法 (Preparation method of high-yield and high-purity pesticide diflubenzuron ) 是由 胡红一 赵辉 汪静莉 杨露 常亚军 方炎林 梅渝晨 于 2021-09-14 设计创作，主要内容包括：本发明涉及一种高收率、高纯度杀虫剂除虫脲的制备方法,包括以下步骤：将混二甲苯和2,6-二氟苯甲酰胺混合后,升温回流脱出部分混二甲苯后,滴加对氯苯基异氰酸酯,滴加结束后保温反应,反应结束后脱出部分混二甲苯,再降温后处理,得到除虫脲。本发明的高收率、高纯度杀虫剂除虫脲的制备方法中采用混二甲苯作为溶剂,具有成本低、质量高,所制备的除虫脲收率在95%以上,除虫脲成品含量高于99%,适合工业化生产。(The invention relates to a preparation method of high-yield and high-purity pesticide diflubenzuron, which comprises the following steps: mixing mixed xylene and 2, 6-difluorobenzamide, heating, refluxing to remove partial mixed xylene, dropwise adding p-chlorophenyl isocyanate, reacting while keeping the temperature, removing partial mixed xylene after reaction, and cooling for post-treatment to obtain diflubenzuron. The preparation method of the high-yield and high-purity diflubenzuron has the advantages that the mixed xylene is used as the solvent, the cost is low, the quality is high, the yield of the prepared diflubenzuron is over 95 percent, the content of the diflubenzuron finished product is over 99 percent, and the preparation method is suitable for industrial production.)

1. A preparation method of high-yield and high-purity diflubenzuron insecticide is characterized by comprising the following steps: the method comprises the following steps:

mixing mixed xylene and 2, 6-difluorobenzamide, heating, refluxing to remove partial mixed xylene, dropwise adding p-chlorophenyl isocyanate, reacting while keeping the temperature, removing partial mixed xylene after reaction, and cooling for post-treatment to obtain diflubenzuron.

2. The process of claim 1 for the preparation of high yield, high purity pesticidal diflubenzuron, wherein: the mixed xylene is a mixture of paraxylene, o-xylene, m-xylene and ethylbenzene.

3. The process of claim 1 for the preparation of high yield, high purity pesticidal diflubenzuron, wherein: the mass ratio of the 2, 6-difluorobenzamide to the p-chlorophenyl isocyanate to the mixed xylene is 1:1.02: 5.

4. The process of claim 1 for the preparation of high yield, high purity pesticidal diflubenzuron, wherein: the method specifically comprises the following steps: mixing mixed xylene and 2, 6-difluorobenzamide, heating to 140-145 ℃, refluxing and desolventizing, dropwise adding p-chlorophenyl isocyanate, keeping the temperature at 140-145 ℃ after dropwise adding, reacting, removing the mixed xylene after the reaction is finished, cooling to 10-15 ℃, and performing post-treatment to obtain the diflubenzuron.

5. The process of claim 1 for the preparation of high yield, high purity pesticidal diflubenzuron, wherein: and finishing the dropwise adding of the p-chlorophenyl isocyanate within 2-2.5 h.

6. The process of claim 1 for the preparation of high yield, high purity pesticidal diflubenzuron, wherein: the reaction time is 4-4.5 h.

7. The process of claim 1 for the preparation of high yield, high purity pesticidal diflubenzuron, wherein: the mass of the mixed xylene removed before reaction accounts for 10-15% of the total mass of the solvent.

8. The process of claim 1 for the preparation of high yield, high purity pesticidal diflubenzuron, wherein: the mass of the mixed xylene removed after the reaction is finished accounts for 32-35% of the total mass of the solvent.

Technical Field

The invention belongs to the technical field of pesticide preparation, and particularly relates to a preparation method of a high-yield and high-purity pesticide diflubenzuron.

Background

Diflubenzuron is a specific and low-toxicity insect growth regulator, belonging to benzoyloxy phenylurea insecticides. The insect killing mechanism is that the larva can not form new epidermis and dead larva body by inhibiting the synthesis of chitin in the insect. The pesticide is effective on various lepidoptera pests, has no phytotoxicity on plants under effective dosage, and has no adverse effect on beneficial organisms such as bird, fish, shrimp, frog, bee, ladybug, parasitic wasp, etc.

The preparation method of diflubenzuron recorded in the prior art has the following disadvantages: (1) the process is complex, and the used catalyst is unreasonable, so that the synthesis yield and purity are low, and the preparation cost is high; (2) the unreasonable solvent is used, which causes the addition of excessive raw materials and can not ensure that the feeding amount reaches the saturation degree of the reaction system.

Chinese patent CN201110083617.0 discloses a method for preparing diflubenzuron, which comprises the steps of taking dimethylformamide and p-chloroaniline as initial raw materials, reacting under the action of phosgene, a catalyst and a cocatalyst to obtain a solution consisting of p-chlorobenzene isocyanate and an aromatic compound solvent, and then dropwise adding the obtained p-chlorobenzene isocyanate and the aromatic compound solvent into a mixture of the aromatic compound solvent and 2, 6-difluorobenzamide to obtain the diflubenzuron; the yield and purity are improved by using two catalysts and a cocatalyst, but the preparation cost is also improved, and the side reaction of moisture in an aromatic compound solvent and the like is not considered in the process of dripping p-chlorobenzene isocyanate and the aromatic compound solvent into the mixture of the aromatic compound solvent and the 2, 6-difluorobenzamide, so that the yield and purity of the diflubenzuron are influenced.

Chinese patent CN202110074727.4 discloses a synthesis process of diflubenzuron and application thereof, wherein the synthesis process of diflubenzuron comprises the following steps: mixing an aromatic hydrocarbon solvent and 2, 6-difluorobenzamide, heating to 130-145 ℃, performing reflux dehydration, cooling, dropwise adding p-chlorophenyl isocyanate, heating to 130-145 ℃ after dropwise adding, reacting, and performing post-treatment to obtain the diflubenzuron. The yield of the diflubenzuron in the patent is more than 92 percent, the purity is more than 97 percent, and a certain difference exists between the purity required by the market and higher than 98 percent.

Disclosure of Invention

The invention aims to provide a preparation method of high-yield and high-purity diflubenzuron, which has the advantages of simple operation, low preparation cost, high yield and content of the prepared diflubenzuron and suitability for industrial production.

The technical scheme adopted by the invention for solving the problems is as follows: a preparation method of high-yield and high-purity diflubenzuron serving as an insecticide comprises the following steps:

after mixing mixed xylene and 2, 6-difluorobenzamide, heating, refluxing and desolventizing, dropwise adding p-chlorophenyl isocyanate, carrying out heat preservation reaction after dropwise adding is finished, after the reaction is finished, removing mixed xylene, and carrying out cooling post-treatment to obtain diflubenzuron.

Preferably, the mixed xylene is a mixture of paraxylene, o-xylene, m-xylene and ethylbenzene.

Preferably, the mass ratio of the 2, 6-difluorobenzamide to the p-chlorophenyl isocyanate to the mixed xylene is 1:1.02: 5.

Preferably, the method specifically comprises the following steps: mixing mixed xylene and 2, 6-difluorobenzamide, heating to 140-145 ℃, refluxing and desolventizing, dropwise adding p-chlorophenyl isocyanate, keeping the temperature at 140-145 ℃ after dropwise adding, reacting, removing the mixed xylene after the reaction is finished, cooling to 10-15 ℃, and performing post-treatment to obtain the diflubenzuron.

Preferably, the dropwise addition of the p-chlorophenyl isocyanate is finished within 2-2.5 h.

Preferably, the reaction time is 4-4.5 h.

Preferably, the mass of the mixed xylene removed before reaction accounts for 10-15% of the total mass of the solvent.

Preferably, the mass of the mixed xylene removed after the reaction is finished accounts for 32-35% of the total mass of the solvent.

The reaction equation of the present invention is as follows:

compared with the prior art, the invention has the advantages that:

(1) the mixed xylene is used as a solvent, and the cost price of the mixed xylene is far lower than that of other aromatic hydrocarbon solvents with the boiling points of 130-140 ℃; the method can remove partial mixed xylene before reaction to completely remove free water in the system, can reduce the dissolving amount of finished products in a solvent in the post-treatment process by removing partial mixed xylene again, improves the reaction yield, and removes 1, 3-bis (4-chlorophenyl) urea which is a main impurity in the reaction (easy to sublime at high temperature) from the system in the process of removing the mixed xylene, thereby improving the product content.

(2) Under the condition of ensuring the yield and the content of the product, the mass ratio of the solvent to the reaction material is optimized (the mass ratio of the 2, 6-difluorobenzamide to the p-chlorophenyl isocyanate to the mixed xylene is 1:1.02: 5), so that the single-kettle yield of the product is greatly improved; after the reaction is finished and part of mixed xylene is removed, the temperature is reduced to 10-15 ℃ for post-treatment, and the solubility of the product in the solvent is reduced so as to improve the product yield.

(3) The mass of the mixed xylene removed before the reaction accounts for 10-15% of the total mass of the solvent, and the mass of the mixed xylene removed after the reaction accounts for 32-35% of the total mass of the solvent, so that the full reaction is ensured, free water in a system is completely removed, and the yield is high, and the method specifically comprises the following steps: excessive desolvation solvent is generated before reaction, the residual solvent amount can not ensure the full reaction of reactants, and if the desolvation solvent is too little, the complete removal of free moisture in the system can not be ensured; excessive solvent removal after the reaction increases the viscosity of the system, the material transferring difficulty is high, and too little solvent removal results in relatively large dissolved amount of the product and low yield.

(4) The synthesis process has the advantages of simple operation, low production cost, high product quality and economic benefit, the yield of the synthesized diflubenzuron is more than 95 percent, the content of the diflubenzuron finished product is more than 99 percent, and the solvent can be recycled, so the synthesis process is more environment-friendly and safer, and is more favorable for industrial production.

Detailed Description

The present invention will be described in further detail with reference to examples.

The xylene is divided into three isomers of o-xylene, m-xylene and p-xylene according to the position difference of two methyl groups. Industrially, mixed xylene means a mixture of the above isomers and ethylbenzene, i.e., a solvent used in the present invention. In the industrial mixed xylene, the content ratios of main components of p-xylene, m-xylene, o-xylene and ethylbenzene in xylene are respectively 30%, 10%, 48% and 12%.

Example 1

Adding 187.5g mixed xylene and 37.5g 2, 6-difluorobenzamide into a 500mL four-neck flask, mixing and stirring, heating the system to 145 ℃, maintaining the reflux state, and removing 19g mixed xylene (taking out all free water in the system); dripping 38.3g of p-chlorophenyl isocyanate within 2 hours, and continuing stirring at 145 ℃ for 4 hours after dripping; after the reaction is finished, 62g of mixed xylene is removed; and cooling the system to 10 ℃, filtering, washing a filter cake by using cold mixed xylene (the temperature is 0-10 ℃, the solubility of the material in the mixed xylene can be reduced), and drying to obtain a diflubenzuron finished product with the content of 99.24% and the yield of 95.57% (calculated by 2, 6-difluorobenzamide).

Example 2

Adding 220g of mixed xylene and 44.0g of 2, 6-difluorobenzamide into a 500mL four-neck flask, mixing and stirring, heating the system to 145 ℃, maintaining a reflux state, and removing 26g of mixed xylene (taking out all free water in the system); 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2.5 hours, and the solution is kept stirring at 145 ℃ for 4.5 hours after the dripping is finished; after the reaction is finished, 72g of mixed xylene is removed; and cooling the system to 10 ℃, filtering, washing a filter cake by cold mixed xylene (at the temperature of 0-10 ℃), and drying to obtain a diflubenzuron finished product with the content of 99.57% and the yield of 96.10% (calculated by 2, 6-difluorobenzamide).

Example 3

220g of mixed xylene and 44.0g of 2, 6-difluorobenzamide are added into a 500mL four-neck flask, and mixed and stirred; the temperature of the system is raised to 145 ℃, the reflux state is maintained, and 26g of mixed xylene (all water free in the system is taken out) is removed; 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2 hours, and the solution is kept stirring at 145 ℃ for 4 hours after the dripping is finished; after the reaction is finished, 72g of mixed xylene is removed; and cooling the system to 10 ℃, filtering, washing a filter cake by taking a small amount of cold mixed xylene (at the temperature of 0-10 ℃), and drying to obtain a diflubenzuron finished product with the content of 99.28 percent and the yield of 96.08 percent (calculated by 2, 6-difluorobenzamide).

Comparative example 1

220g of toluene and 44.0g of 2, 6-difluorobenzamide are added into a 500mL four-neck flask, and mixed and stirred; the temperature of the system is raised to 110.6 ℃, the reflux state is maintained, and 26g of toluene (all free water in the system is taken out) is removed; 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2 hours, and the solution is kept stirring at the temperature of 110.6 ℃ for 4 hours after the dripping is finished; after the reaction is finished, removing 72g of toluene; and cooling the system to 10 ℃, filtering, washing a filter cake by using cold toluene (at the temperature of 0-10 ℃), and drying to obtain a diflubenzuron finished product with the content of 98.75% and the yield of 91.76% (calculated by 2, 6-difluorobenzamide).

Comparative example 2

Adding 220g of mixed xylene and 44.0g of 2, 6-difluorobenzamide into a 500mL four-neck flask, mixing and stirring, and heating the system to 145 ℃; 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2 hours, and the solution is kept stirring at 145 ℃ for 4 hours after the dripping is finished; after the reaction is finished, 72g of mixed xylene is removed; and cooling the system to 10 ℃, filtering, washing a filter cake by cold mixed xylene (at the temperature of 0-10 ℃), and drying to obtain a diflubenzuron finished product with the content of 95.69% and the yield of 90.06% (calculated by 2, 6-difluorobenzamide).

Comparative example 3

220g of mixed xylene and 44.0g of 2, 6-difluorobenzamide are added into a 500mL four-neck flask, and mixed and stirred; the temperature of the system is raised to 145 ℃, the reflux state is maintained, and 26g of mixed xylene (all water free in the system is taken out) is removed; 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2 hours, and the solution is kept stirring at 145 ℃ for 4 hours after the dripping is finished; and cooling the system to 10 ℃, filtering, washing a filter cake by cold mixed xylene (at the temperature of 0-10 ℃), and drying to obtain a diflubenzuron finished product with the content of 96.72% and the yield of 88.75% (calculated by 2, 6-difluorobenzamide).

Comparative example 4

Adding 220g of mixed xylene and 44.0g of 2, 6-difluorobenzamide into a 500mL four-neck flask, mixing and stirring, heating the system to 145 ℃, maintaining a reflux state, and removing 26g of mixed xylene (taking out all free water in the system); 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2 hours, and the solution is kept stirring at 145 ℃ for 4 hours after the dripping is finished; after the reaction is finished, 72g of mixed xylene is removed; and cooling the system to 10 ℃, filtering, washing a filter cake by cold mixed xylene (at the temperature of 0-10 ℃), and drying to obtain a diflubenzuron finished product with the content of 99.32% and the yield of 95.53% (calculated by 2, 6-difluorobenzamide).

Comparative example 5

Adding 220g of mixed xylene and 44.0g of 2, 6-difluorobenzamide into a 500mL four-neck flask, mixing and stirring, heating the system to 145 ℃, maintaining a reflux state, and removing 10g of mixed xylene (taking out all free water in the system); 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2 hours, and the solution is kept stirring at 145 ℃ for 4 hours after the dripping is finished; after the reaction is finished, 72g of mixed xylene is removed; and cooling the system to 10 ℃, filtering, washing a filter cake by cold mixed xylene (at the temperature of 0-10 ℃), and drying to obtain a diflubenzuron finished product with the content of 98.12% and the yield of 95.10% (calculated by 2, 6-difluorobenzamide).

Comparative example 6

Adding 220g of mixed xylene and 44.0g of 2, 6-difluorobenzamide into a 500mL four-neck flask, mixing and stirring, heating the system to 145 ℃, maintaining a reflux state, and removing 26g of mixed xylene (taking out all free water in the system); 44.9g of p-chlorophenyl isocyanate is dripped in the solution within 2 hours, and the solution is kept stirring at 145 ℃ for 4 hours after the dripping is finished; after the reaction is finished, removing 36g of mixed xylene; and cooling the system to 10 ℃, filtering, washing a filter cake by using cold mixed xylene (the temperature is 0-10 ℃, the solubility of the material in the mixed xylene can be reduced), and drying to obtain a diflubenzuron finished product with the content of 98.53 percent and the yield of 92.46 percent (calculated by 2, 6-difluorobenzamide).

In addition to the above embodiments, the present invention also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of the claims of the present invention.