CN110698421A

CN110698421A - Synthesis method of benzoxazolone

Info

Publication number: CN110698421A
Application number: CN201911288808.3A
Authority: CN
Inventors: 刘林波; 田轮; 胡志彬; 王宇; 龚小丽
Original assignee: Hunan Suobo Biotechnology Co Ltd
Current assignee: Hunan Suobo Biotechnology Co Ltd
Priority date: 2019-12-16
Filing date: 2019-12-16
Publication date: 2020-01-17
Anticipated expiration: 2039-12-16
Also published as: CN110698421B

Abstract

The invention relates to the technical field of organic synthesis, in particular to a method for continuously synthesizing benzoxazolone in a horizontal double-spiral reactor in a molten state. Compared with the traditional solvent-free method, the method has the advantages that the reaction device is a horizontal double-helix reactor, the method is continuous, uniform in heating, good in stirring effect, short in reaction time and the like, the atomic utilization rate of the product is high, the yield is 97.3-98.5% (calculated by 2-aminophenol), the content is 98.3-99.1% (liquid chromatography, external standard), the amount of three wastes is small, the method is easy to process, the operation is simple, and the automatic production is facilitated.

Description

Synthesis method of benzoxazolone

Technical Field

The invention relates to the technical field of organic synthesis, in particular to a continuous method for synthesizing benzoxazolone in a solvent-free system.

Background

The benzoxazolone (Benzoxazolinone) is a light yellow solid in appearance and has a melting point of 140-142 ℃. The molecular formula is as follows: c₇H₅NO₂Molecular weight: 135.12, molecular structural formula:

the chemical properties of the benzoxazolone are relatively active, for example, the hydrogen atom on the 3-position in the molecular structural formula can perform hydroxymethylation reaction with formaldehyde, the hydrogen on the 6-position of a benzene ring is easily replaced by chlorine, and the benzoxazolone can be easily subjected to ring opening in a strong alkaline medium to generate 2-hydroxy-phenylamino and the like. These properties make benzoxazolones an important use in pesticides, medicine and other fields. In the aspect of pesticides, benzoxazolone is an important intermediate of high-efficiency low-toxicity herbicide such as fenoxaprop-P-ethyl and metamifop, and pesticide such as vozapyr, and the benzoxazolone can be used for producing various analgesics, hypnotics and antipyretics in the aspect of medicine, and the following methods are mainly reported at present.

CN105669477 discloses a method for high-temperature cyclization of 2-aminophenol and urea in 48% sulfuric acid water solution, although the by-product ammonia gas generated in the reaction can be directly absorbed by dilute acid, the corrosion of strong acid medium at high temperature to equipment is serious, and three wastes are more, which is not beneficial to environmental protection.

Yuanli et al (synthesis and biological activity of N-substituted benzoxazolinone and N-substituted benzoxazolinone compounds [ J ] modern pesticides 2009, 8(01): 15-19) report a method for preparing benzoxazolone by using 2-aminophenol and solid phosgene, and although the method has the advantages of simple operation, high yield and the like, the method has the disadvantages that solid phosgene with high toxicity is used, and corrosive gas as a byproduct corrodes equipment seriously, thus being not beneficial to industrial production.

CN1398857 discloses a method for synthesizing benzoxazolone from 2-nitrophenol and carbon monoxide, which reduces the use of toxic substances such as phosgene, but the reaction catalyst is selenium powder, and the catalytic reaction is carried out under high pressure, requiring special equipment; although the subsequent improvement makes the catalytic reaction proceed under normal pressure, the product is purified by column chromatography, and the disadvantages of low yield and the like are not improved, so that the method is not suitable for industrial production.

CN 108794421 discloses a method for synthesizing benzoxazolone from 2-aminophenol and urea in DMF at high temperature, but the purification method is column chromatography, the yield is low, the operation is complex, and is not beneficial to industrial production, and organic solvent is used, and a large amount of organic waste liquid is generated.

Ligustrum lucidum (review of benzoxazolone synthesis methods [ J ]. Hunan chemical industry, 1994, (03): 14-17.) reports a traditional method for synthesizing benzoxazolone in a solvent-free system, wherein 2-aminophenol and urea are added into a three-neck flask, and then the temperature is gradually increased from low to high, so that the mixture reacts in a molten state to obtain the benzoxazolone. Although the method reduces the use of organic solvents, the temperature is high, the reaction time is long, the color of the product is dark, further decolorization treatment is needed, and the yield is only 82%.

Disclosure of Invention

The invention mainly aims to overcome the problems that an organic solvent system is used in the traditional benzoxazolone synthesis process, which is not beneficial to environmental protection and the like, and provides a continuous synthesis method of benzoxazolone in a solvent-free system, wherein the method has mild reaction conditions and small corrosion to equipment; the post-treatment is simple, the reaction liquid is only required to be transferred into hot water for cooling, crystallization, filtration and drying, the reaction and the post-treatment have continuity, the operation procedures are reduced, and the waste materials generated in industrial production are greatly reduced due to the fact that no organic solvent is used in a reaction system, so that the whole process is more environment-friendly.

In order to achieve the purpose, the invention adopts the following technical scheme:

continuously adding 2-aminophenol and urea at a certain temperature in a horizontal double-spiral reactor with the relative vacuum degree of-0.01 MPa to-0.02 MPa according to a fixed proportion, reacting the reaction materials in the reactor under the spiral push, timely removing the generated ammonia gas by negative pressure air suction, continuously transferring the reaction materials to hot water, cooling and crystallizing, filtering and drying to obtain the benzoxazolone.

The reaction formula is as follows:

the invention adopts a continuous method to synthesize the benzoxazolone by the 2-aminophenol and the urea, does not use organic solvent in the reaction and post-treatment processes, effectively reduces the problems of raw material cost, VOCs and the like in three wastes, has mild and easily-controlled continuous reaction conditions and high product quality and yield, and has important significance for industrial production.

Preferably, the molar ratio of 2-aminophenol to urea is controlled during the reaction between 1:1.1 to 1.5. The conversion rate and yield of the reaction in the molar ratio are better, the by-products are less, and when the molar ratio of the 2-aminophenol to the urea is less than 1:1.1, the 2-aminophenol is remained.

Preferably, the relative degree of vacuum in the horizontal double-screw reactor is set to-0.01 MPa to-0.02 MPa. The negative pressure is more beneficial to removing the by-product ammonia gas out of the reaction system from distillation and condensation, and the reaction process is accelerated.

Preferably, the reaction temperature is controlled to be 120-150 ℃ in the reaction process. The reaction is more complete and byproducts are less in the temperature range, and when the reaction temperature is lower than 120 ℃, more 2-aminophenol remains and the conversion rate is low; and when the temperature is higher than 150 ℃, the color of the product is darkened, and the content is reduced, so that the temperature must be strictly controlled to be 120-150 ℃ to ensure that the yield and the content of the product are high.

Preferably, the reaction time is controlled within 0.5-1 h, the conversion rate of the raw materials in the reaction time is relatively high, and the quality of the product can be ensured.

Preferably, the temperature of the hot water is 50-90 ℃, the solid particles of the cooling crystallization are relatively uniform in the temperature range, and the solid particles of the cooling crystallization are relatively large when the temperature is lower than 50 ℃, and even the caking phenomenon affects the product quality.

Preferably, the mass of the hot water used is 1 time or more of that of the 2-aminophenol, and when the mass is less than 1 time, the cooled and crystallized solid is viscous, the stirring effect is poor, and the content is low.

Preferably, the cooling crystallization temperature is 10-30 ℃, the solid content and yield of the crystals in the temperature range are high, the temperature is lower than 10 ℃, the content of the product is lower, and the yield is slightly lower when the temperature is higher than 30 ℃.

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

1) the reactor is a horizontal double-helix reactor, the materials are heated uniformly, the stirring effect is good, and the reaction time is convenient to control;

2) the product content is high and is 98.3-99.1% (liquid chromatography, external standard);

3) the yield is high and is 97.3 to 98.5 percent (calculated by 2-aminophenol);

4) the post-treatment is simple, the reaction process and the post-treatment are continuous, the quality is stable, and the automatic production is convenient;

5) organic solvent is not used in the reaction system, the amount of three wastes is small, and the treatment is easy, so that the whole process is more environment-friendly;

6) the generated ammonia gas can be absorbed by sulfuric acid to prepare byproducts such as ammonium sulfate and the like.

Detailed Description

Example 1:

the rotating speed of a 2000mL horizontal double-helix reactor is controlled well, the system is under negative pressure (the relative vacuum degree is-0.02 MPa), the temperature is raised to 120 ℃, 660.0g (6.05 mol) of 2-aminophenol and 399.6g (6.66 mol) of urea are continuously added into the horizontal double-helix reactor according to the proportion, the average residence time of the molten materials in the reactor is 1h, and the generated ammonia gas is removed out of the system in time. The reaction material is transferred into 1320.0g of 90 ℃ water while the reaction material is hot, is continuously stirred for 30min, is cooled to 30 ℃, is filtered and dried to obtain 795.1g of benzoxazolone with the content of 99.1 percent (external standard of liquid chromatography) and the yield of 97.3 percent (calculated by 2-aminophenol).

Example 2:

the rotating speed of a 2000mL horizontal double-helix reactor is controlled well, the system is under negative pressure (the relative vacuum degree is-0.01 MPa), the temperature is raised to 150 ℃, 660.0g (6.05 mol) of 2-aminophenol and 435.9g (7.26 mol) of urea are continuously added into the horizontal double-helix reactor according to the proportion, the average residence time of the molten materials in the reactor is 0.5h, and the generated ammonia gas is removed out of the system in time. The reaction mass is transferred into 660.0g of 50 ℃ water while hot, is continuously stirred for 30min, is cooled to 20 ℃, is filtered and dried to obtain 803.3g of benzoxazolone with the content of 98.7 percent (external standard of liquid chromatography) and the yield of 98.3 percent (calculated by 2-aminophenol).

Example 3:

the rotating speed of a 2000mL horizontal double-helix reactor is controlled well, the system is under negative pressure (the relative vacuum degree is-0.01 MPa), the temperature is raised to 120 ℃, 660.0g (6.05 mol) of 2-aminophenol and 544.9g (9.07 mol) of urea are continuously added into the horizontal double-helix reactor according to the proportion, the average residence time of the molten materials in the reactor is 0.8h, and the generated ammonia gas is removed out of the system in time. The reaction mass is transferred into 1320.0g of 70 ℃ water while hot, is continuously stirred for 30min, is cooled to 10 ℃, is filtered and dried to obtain 804.9g of benzoxazolone with the content of 98.9 percent (external standard of liquid chromatography) and the yield of 98.5 percent (calculated by 2-aminophenol).

Example 4:

the rotating speed of a 2000mL horizontal double-helix reactor is controlled well, the system is under negative pressure (the relative vacuum degree is-0.02 MPa), the temperature is raised to 140 ℃, 660.0g (6.05 mol) of 2-aminophenol and 472.2g (7.86 mol) of urea are continuously added into the horizontal double-helix reactor according to the proportion, the average residence time of the molten materials in the reactor is 0.6h, and the generated ammonia gas is removed out of the system in time. The reaction mass is transferred into 1000.0g of water with the temperature of 80 ℃ while the reaction mass is hot, the mixture is continuously stirred for 30min, cooled to 30 ℃, filtered and dried to obtain 799.2g of benzoxazolone with the content of 98.3 percent (external standard of liquid chromatography) and the yield of 97.8 percent (calculated by 2-aminophenol).

Example 5:

the rotating speed of a 2000mL horizontal double-helix reactor is controlled well, the system is under negative pressure (the relative vacuum degree is-0.02 MPa), the temperature is raised to 130 ℃, 660.0g (6.05 mol) of 2-aminophenol and 508.5g (8.47 mol) of urea are continuously added into the horizontal double-helix reactor according to the proportion, the average residence time of the molten materials in the reactor is 0.7h, and the generated ammonia gas is removed out of the system in time. The reaction mass is transferred into 800.0g of 90 ℃ water while hot, is continuously stirred for 30min, is cooled to 20 ℃, is filtered and dried to obtain 802.5g of benzoxazolone with the content of 99.1 percent (external standard of liquid chromatography) and the yield of 98.2 percent (calculated by 2-aminophenol).

Example 6:

the rotating speed of a 2000mL horizontal double-helix reactor is controlled well, the system is under negative pressure (the relative vacuum degree is-0.01 MPa), the temperature is raised to 120 ℃, 660.0g (6.05 mol) of 2-aminophenol and 435.9g (7.26 mol) of urea are continuously added into the horizontal double-helix reactor according to the proportion, the average residence time of the molten materials in the reactor is 0.9h, and the generated ammonia gas is removed out of the system in time. The reaction mass is transferred into 1320.0g of 60 ℃ water while hot, is continuously stirred for 30min, is cooled to 30 ℃, is filtered and dried to obtain 800.8g of benzoxazolone with the content of 98.7 percent (external standard of liquid chromatography) and the yield of 98.0 percent (calculated by 2-aminophenol).

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-described embodiments. All technical schemes belonging to the idea of the invention belong to the protection scope of the invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention, and such modifications and embellishments should also be considered as within the scope of the invention.

Claims

1. A synthetic method of benzoxazolone is characterized in that: continuously adding 2-aminophenol and urea into a horizontal double-spiral reactor with the relative vacuum degree of-0.01 MPa to-0.02 MPa, stirring, heating for reaction, transferring the reaction materials into hot water after the reaction in the reactor is finished under the drive of a spiral, cooling for crystallization, filtering and drying to obtain the benzoxazolone.

2. The method for synthesizing benzoxazolone according to claim 1, characterized in that the molar ratio of 2-aminophenol to urea is controlled between 1:1.1 to 1.5.

3. The method for synthesizing benzoxazolone according to claim 1, characterized in that the reaction temperature is controlled at 120-150 ℃.

4. The method for synthesizing benzoxazolone according to claim 1, characterized in that the reaction time is 0.5-1 h.

5. The method for synthesizing benzoxazolone according to claim 1, characterized in that the temperature of hot water is 50-90 ℃.

6. The method for synthesizing benzoxazolone according to claim 1, characterized in that the mass of hot water is more than 1 time of the mass of 2-aminophenol.

7. The method for synthesizing benzoxazolone according to claim 1, characterized in that the cooling crystallization temperature is 10-30 ℃.