Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

A method for removing N-nitroso compounds from pendimethalin

A technology of nitroso compounds and pendimethalin, which is applied in the purification/separation of amino compounds, organic chemistry, etc., can solve the problem that hydrochloric acid is not well utilized, so as to reduce the formation of waste salt, prolong the reaction time, The effect of reducing the content of N-nitroso compounds

Active Publication Date: 2019-07-05
JIANGSU YONGAN CHEM CO LTD
View PDF15 Cites 5 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] Moreover, the hydrochloric acid used in the above conversion scheme has not been well utilized, and is usually treated as wastewater, and a large amount of waste salt is generated during the treatment process

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A method for removing N-nitroso compounds from pendimethalin

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Preparation of pendimethalin

[0037] Add pentylamine to 1,2-dichloroethane to dissolve, heat to 50-60°C, add 35-45% nitric acid dropwise, control the reaction temperature at 50-60°C, and layer to obtain dilute nitric acid with a concentration of 1-4% into the wastewater treatment system .

[0038] The organic phase obtained by stratification is added dropwise with 68-70% nitric acid, and the dropping temperature is controlled at 50-60°C. After the addition is completed, the reaction is kept for 30 minutes, and the nitric acid (concentration 30-40%) layer is separated, and the organic phase is washed with water and separated. Aqueous phase influent treatment system. The organic phase obtained by stratification is dichloroethane solution of pendimethalin crude product, and analyzed by HPLC, wherein the content of N-nitroso compounds is less than or equal to 30%.

[0039] De-N-nitroso compounds

[0040] Add 15 g of ammonium chloride, 30% 75g of hydrochloric acid, heat...

Embodiment 2

[0042] Add 6 g of ammonium chloride, 25% 30g of hydrochloric acid, heated up to 82°C and reacted for 6 hours, sampled, analyzed by HPLC, the content of N-nitroso compounds in the reaction solution was less than 0.05%, and the reaction was stopped. Add 60g water in reaction system, leave standstill layering after stirring, separate organic phase, organic phase washes with 100g 5% NaOH solution successively, 100g water washes, 100g 2% hydrochloric acid washes, after 100g water washes, normal pressure concentration reclaims solvent to After the internal temperature reached 130°C, vacuum precipitation was carried out to obtain 90 g of pendimethalin product. The content is 97.8%. The content of N-nitroso compounds is 1200 ppm.

Embodiment 3

[0044] Add 6 g of ammonium chloride, 25% 90g of hydrochloric acid, heated up to 78°C and reacted for 6 hours, sampled, analyzed by HPLC, the content of N-nitroso compounds in the reaction solution was less than 0.05%, and the reaction was stopped. The reaction device is connected to the water separator, and distilled at atmospheric pressure until the internal temperature rises to 100°C, and no more water is produced in the water separator, and the distillation is completed (during the solvent distillation process, the water is continuously separated through the water separator, and the organic solvent Return to the distillation device), the distillation time is about 6h, the organic phase after distillation is washed successively with 100g 5% NaOH solution, 100g water wash, 100g 2% hydrochloric acid wash, after 100g water wash, normal pressure concentration recovery solvent recovery solvent to the internal temperature to After 135°C, 132 g of pendimethalin product was obtained...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A method for removing N-nitroso compounds from pendimethalin is disclosed. The method includes adding hydrochloric acid, ammonium chloride and an auxiliary catalyst into a dichloroethane solution of the pendimethalin containing N-nitroso compounds; heating the mixture to 78-82 DEG C; reacting and stirring the mixture for 6-10 h until the N-nitroso compound content of the reaction system is lower than 0.05%; and subjecting the reaction solution to aftertreatment, and concentration to remove a solvent to obtain a pendimethalin product. According to the method, the ammonium chloride is adopted asan additive for nitroso compound removal under the existence of concentrated hydrochloric acid, and the ammonium chloride reacts with nitrosyl chloride generated during nitroso compound removal to form ammonium nitrite which is unstable and liable to decompose into nitrogen and water, and hydrogen chloride which is dissolved into water to form hydrochloric acid, thus avoiding introduction of organic impurities and avoiding generation of salt-containing waste water.

Description

technical field [0001] The invention belongs to the field of herbicide preparation and relates to the preparation of pendimethalin, in particular to a method for removing N-nitroso compounds from pendimethalin. Background technique [0002] Pendimethalin is an aniline herbicide developed by American Cyanamid Corporation (now owned by BASF). The original drug is orange-yellow crystal with a melting point of 56-58°C. It has little solubility in water, is easily soluble in chlorinated hydrocarbons and aromatic hydrocarbon solvents, and is stable to acid and alkali. [0003] At present, pendimethalin production technology mainly uses N-(3-pentyl)-2,3-xylaniline as raw material and concentrated nitric acid as nitrating agent. During the nitration process, the N atom of the amino group is easy to form N-NO products (US4136117), so there is a process of removing nitroso groups after nitration in the production process, and the obtained product is post-processed and concentrated to...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C07C209/86C07C211/52
CPCC07C209/86C07C211/52
Inventor 耿敬坤方浙能陈夕鹏厉大双
Owner JIANGSU YONGAN CHEM CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com