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Method for preparing 3-(3,4-dichlorophenyl)-1-methoxy-1-methyl urea

A technology of dichlorophenyl and dichlorophenyl isocyanate, applied in the field of preparation of 3--1-methoxy-1-methylurea, which can solve the problems of low manufacturing cost, difficult treatment of salty wastewater, unsafe production, etc. problems, to achieve the effect of excellent quality, less three wastes, and less pollution

Active Publication Date: 2010-07-21
JIANGSU KUAIDA AGROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The above-mentioned synthetic route has low manufacturing cost and is currently the commonly used method for producing 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea, but this process uses the highly toxic chemical disulfate Methyl ester is used as a raw material, and the production is extremely unsafe. At the same time, a large amount of by-product monomethyl sodium sulfate is generated, and a large amount of saline wastewater is difficult to treat.

Method used

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  • Method for preparing 3-(3,4-dichlorophenyl)-1-methoxy-1-methyl urea
  • Method for preparing 3-(3,4-dichlorophenyl)-1-methoxy-1-methyl urea

Examples

Experimental program
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Embodiment 1

[0031] 1. Add 250ml of toluene and 50g of 3,4-dichloroaniline to the flask, stir to raise the temperature, reflux for dehydration, and obtain 3,4-dichloroaniline toluene solution for later use.

[0032] 2. Take another flask, add 250ml of toluene to it, lower the temperature, and pass in phosgene. When the temperature drops to about 0°C, start to add the above-prepared 3,4-dichloroaniline toluene solution dropwise. Enter phosgene for about 2 hours, the flow rate of phosgene is: 200-250ml / min (the amount of phosgene introduced is about 48-60g), and the reaction temperature is controlled below 5°C.

[0033] 3. Then slowly raise the temperature, 4h~5h to 80°C, then keep warm at 80°C~90°C for 1h, the transparent material is the end point of the reaction. After the reaction is completed, use nitrogen to drive phosgene at 80°C to 90°C for 3h to 4h to obtain a toluene solution of 3,4-dichlorophenylisocyanate for later use.

[0034] 4. Pour the toluene solution of 3,4-dichlorophenyli...

Embodiment 2

[0038] The synthesis of 1-hydroxy-3-(3,4-dichlorophenyl)urea is the same as in Example 1.

[0039] Put 30g of dry product of 1-hydroxy-3-(3,4-dichlorophenyl)urea into the flask equipped with rectification tower (ф24mm×600mm), 100ml of solvent diethylene glycol dimethyl ether, dimethyl carbonate 40g, (Bu) 4 NBr / K 2 CO 3 (where (Bu) 4 NBr: 0.5g, K 2 CO 3 : 5g) heat up to 85°C to 90°C for heat preservation reaction, as the reaction proceeds, methanol is continuously generated, and the generated methanol is not rectified, but remains in the reaction vessel. After 6 hours of reaction, the temperature is raised to reflux for 4 hours , after the reaction is over, cool down, filter with suction, distill off the solvent under reduced pressure, then add ethanol (or mother liquor) for recrystallization to obtain 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea 25.5 g, the content is 90.5%, and the yield is 75.4% (not discounted). Appearance: white solid.

Embodiment 3

[0041] The synthesis of 1-hydroxy-3-(3,4-dichlorophenyl)urea is the same as in Example 1.

[0042] Put 30g of dry product of 1-hydroxy-3-(3,4-dichlorophenyl)urea into the flask equipped with rectification tower (ф24mm×600mm), 100ml of solvent DMF, 40g of dimethyl carbonate, (Bu) 4 NBr / K 2 CO 3 (where (Bu) 4 NBr: 0.5g, K 2 CO 3 : 5g) heat up to 85°C to 90°C for heat preservation reaction, as the reaction proceeds, methanol is continuously generated, and at the same time, the generated methanol is continuously distilled out. After 6 hours of reaction, the temperature is raised to 125°C to 130°C for reaction 4h, after the reaction is over, cool down, filter with suction, distill off the solvent under reduced pressure, then add ethanol (or mother liquor) for recrystallization to obtain 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea 27.5g, the content is 94.7%, the yield is: 81.4% (not 100%). Appearance: brown solid.

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Abstract

The invention discloses a method for preparing 3-(3,4-dichlorophenyl)-1-methoxy-1-methyl urea, which comprises the following steps: taking carbonyl chloride as an acylating agent to carry out an acylation reaction with 3,4-dichlorophenyl; obtaining 3,4-dichlorophenyl isocyanate; generating 1-hydroxy-3-(3,4-dichlorophenyl) urea by the reaction of 3,4-dichlorophenyl isocyanate and hydroxylamine sulfate or hydroxylamine hydrochloride under an alkaline condition; neutralizing 1-hydroxy-3-(3,4-dichlorophenyl) urea and alkali; and obtaining 3-(3,4-dichlorophenyl)-1-methoxy-1-methyl urea by a methylation reaction of 1-hydroxy-3-(3,4-dichlorophenyl) urea and dimethyl carbonate under the condition with a catalyst and a solution. The invention has less quantity of three wastes, high yield, good quality and complete reaction, and can reduce pollution and the cost.

Description

Technical field: [0001] The invention relates to a method for preparing 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea. Background technique: [0002] 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea is a substituted urea systemic herbicide and a photosynthesis inhibitor. With the continuous development of agricultural economy and technology, planting The continuous update of the method has promoted the continuous expansion of the demand for herbicides, and has developed towards the trend of high efficiency, low toxicity and low residue. According to calculations by the Ministry of Agriculture and relevant experts, the current planting area of ​​sugarcane, citrus, pineapple, asparagus, temperate trees and shrubs in my country is about 2 million hectares, and 3-(3,4-dichlorophenyl)-1-methoxy The demand for -1-methylurea will increase. [0003] According to the data, the synthetic method of 3-(3,4-dichlorophenyl)-1-methoxyl-1-methylurea mainly contains the following two kinds: ...

Claims

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Application Information

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IPC IPC(8): C07C275/64C07C273/18
Inventor 李梅芳施永平
Owner JIANGSU KUAIDA AGROCHEM
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