Method for closed-loop synthesis of nicosulfuron by using hydrogen sulfide

A technology of nicosulfuron and hydrogen sulfide, applied in the direction of organic chemistry, etc., can solve the problems of large amount of waste water, complex production process, poor controllability of process safety, etc., achieve high comprehensive utilization rate of resources, simple process equipment, improved The effect of the production environment

Active Publication Date: 2021-10-01
ZIBO NAB AGROCHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] The above three synthetic routes all use 2-chloronicotinic acid as the starting material, and first react with thionyl chloride to generate 2-chloronicotinyl chloride. This step reaction produces a large amount of sulfur dioxide and hydrogen chloride gas. As the reaction proceeds, these two The gas is produced at the same time and it is difficult to completely separate, so the by-products of hydrochloric acid and sodium sulfite have poor purity
The current methods for treating nicosulfuron production wastewater have disadvantages such as complex production process, low production efficiency, large amount of wastewater, complicated environmental protection treatment measures, high production cost, and poor controllability of process safety in some cases.

Method used

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  • Method for closed-loop synthesis of nicosulfuron by using hydrogen sulfide
  • Method for closed-loop synthesis of nicosulfuron by using hydrogen sulfide
  • Method for closed-loop synthesis of nicosulfuron by using hydrogen sulfide

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Step a: Preparation of cyanoalkene intermediate

[0051] Mix 16.4 grams (0.1mol) of tetramethoxypropane with 11.3 grams (0.1mol) of ethyl cyanoacetate, add 0.16 grams of zinc chloride as a catalyst, and then add 65 grams of methanol, heat to 65 ° C for 6 hours, and the reaction is complete , Atmospheric distillation first, distill out methanol for mechanical use, then distill out unreacted raw materials under reduced pressure, and then collect cyano-alkene. Its purity as determined by gas chromatography is 95.5%, and the yield is 95.2%;

[0052] Step b: Preparation of thiols

[0053] Take 18.9 grams of the cyanoalkene intermediate obtained in step a (purity 95.5%, 0.1 mol) and add it to the reaction flask, add 150 milliliters of dichloroethane, start stirring and cool down to 10 ° C, slowly start to feed hydrogen sulfide gas, The reaction temperature is controlled at 10-15°C. During the reaction process, samples are continuously taken for analysis until the remaining ...

Embodiment 2

[0061] Step a: Preparation of cyanoalkene intermediate

[0062] Mix 16.4 grams (0.1mol) of tetramethoxypropane with 12.4 grams (0.11mol) of ethyl cyanoacetate, add 0.3 grams of catalyst zinc chloride, then add 65 grams of methanol, heat to 65 ° C for 6 hours, and the reaction is complete , Atmospheric distillation first, distill out methanol for mechanical use, then distill out unreacted raw materials under reduced pressure, and then collect cyano-alkenes. Its purity as determined by gas chromatography is 96.2%, and the yield is 95.9%;

[0063] Step b: Preparation of thiols

[0064] Take 18.9 grams of the cyanoalkene intermediate obtained in step a (purity 95.5%, 0.1 mol) and add it to the reaction flask, add 150 milliliters of dichloroethane, start stirring and cool down to 10 ° C, slowly start to feed hydrogen sulfide gas, The reaction temperature is controlled at 10-15°C. During the reaction process, samples are continuously taken for analysis until the remaining cyanoalk...

Embodiment 3

[0072] Step a: Preparation of cyanoalkene intermediate

[0073] Mix 16.4 grams (0.1mol) of tetramethoxypropane with 11.3 grams (0.1mol) of ethyl cyanoacetate, add 0.16 grams of catalyst zinc chloride, then add 70 grams of ethanol, heat to 80 ° C for 6 hours, and the reaction is complete , Atmospheric distillation first, distill out methanol for mechanical use, then distill out unreacted raw materials under reduced pressure, and then collect cyano-alkenes. Its purity as determined by gas chromatography is 95.9%, and the yield is 95.6%;

[0074] Step b: Preparation of thiols

[0075] Take 18.9 grams of the cyanoalkene intermediate obtained in step a (purity 95.5%, 0.1 mol) and add it to the reaction flask, add 150 milliliters of dichloroethane, start stirring and cool down to 10 ° C, slowly start to feed hydrogen sulfide gas, Control the reaction temperature at 70-75°C. During the reaction process, keep sampling and testing until the remaining cyanoalkene is less than 2%, stop...

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Abstract

The invention belongs to the technical field of nicosulfuron original medicine production, and particularly relates to a method for closed-loop synthesis of nicosulfuron by using hydrogen sulfide, wherein the method comprises the following steps: reacting tetramethoxypropane with ethyl cyanoacetate to generate 1-cyano-4-methoxy-1-ethoxycarbonyl-1,3-butadiene (cyanoene for short, the same below); reacting cyano alkene with hydrogen sulfide to generate ethyl 2-mercaptonicotinate (sulfydryl substance for short) in a closed-loop manner; reacting the sulfydryl substance with dimethylamine, and then carrying out oxychlorination reaction to obtain sulfonyl chloride; carrying out ammonolysis reaction on the sulfonyl chloride and ammonia gas to obtain sulfonamide; and reacting sulfonamide with solid light and pyrilamine to obtain the nicosulfuron. According to the method for closed-loop synthesis of nicosulfuron by using hydrogen sulfide, each reaction step is mild and controllable, process equipment is simple, the production cost is low, the product quality is good, three wastes are reduced, energy is saved, the production environment is improved, and the goal of carbon neutralization is favorably realized.

Description

technical field [0001] The invention belongs to the technical field of producing nicosulfuron technical field, and in particular relates to a method for synthesizing nicosulfuron by hydrogen sulfide ring closure. Background technique [0002] The trade name of Nicosulfuron is Yunongle. It is a high-efficiency selective post-emergence herbicide for corn fields. It is mainly used to control weeds in winter and spring corn fields. Its dosage is low, its effect is good, and it is safe for corn and the environment. The majority of farmers welcome that nicosulfuron is an important high-efficiency green herbicide, and its main synthesis routes are as follows: [0003] (1) Urethane method route: [0004] Using 2-chloronicotinic acid as the raw material, first react with thionyl chloride to generate 2-chloronicotinyl chloride, then react with dimethylamine to obtain the intermediate 2-chloronicotinamide; then react with sodium hydrosulfide to obtain mercapto The sulfhydryl compound...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D401/12
CPCC07D401/12
Inventor 邵长禄崔元兴陈勇郑有奎
Owner ZIBO NAB AGROCHEM
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