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Separation and recovery process after imidacloprid synthesis

A technology for separation and recovery, imidacloprid, applied in the direction of organic chemistry, etc., can solve the problems of high boiling point of DMF solvent, low recovery rate, large input amount, etc., and achieve the effect of shortening the production cycle, improving the recovery rate and reducing the amount of waste water.

Active Publication Date: 2010-12-22
SHANGDONG HAILIER CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Due to the high boiling point of the DMF solvent itself, it is difficult to completely desolventize and recover in industrial production, and the residual DMF enters the post-treatment section to generate a large amount of wastewater
At the same time, due to the excessive input of 2-nitroiminoimidazolidine raw materials in the DMF method imidacloprid condensation process, it needs to be recycled. Most of the recycling processes use hot water to dissolve and then cool down to recrystallize, and finally dry and reuse. This process is inefficient. A lot of waste water, high energy consumption, complex process and low recovery rate affect the purity of imidacloprid products
[0007] Both the hot water method and the dichloroethane method in the DMF method imidacloprid condensation process are faced with the above two technical problems, which are not conducive to the industrial production of imidacloprid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1: the separation and recovery process after the synthetic imidacloprid of the present invention

[0042] 1. Concrete steps of reclaiming 2-nitroiminoimidazolidine

[0043] Step 1: Add 1000kg 2-nitroimidazolidine, 148kg NaOH and 2500L solvent dimethylformamide (DMF) to the synthesis kettle, drop 2-chloro-5 chloromethylpyridine solution (500kg 2-chloro-5 Chloromethylpyridine and 1500L DMF) were subjected to condensation reaction, and the synthesized reaction liquid was adjusted to acid and filtered salt, then transferred to the DMF desolventizer and distilled at -0.1 to -0.095 MPa, 60-80°C, and the DMF was distilled under negative pressure. Stop when the distillate volume is 90%-95% of the original volume;

[0044] Step 2: When the temperature of the DMF precipitation kettle is lowered to below 30°C, inject 4000L of dichloroethane, start stirring and heat up to 60°C, and continue to keep warm and stir for 30 minutes;

[0045] Step 3: Stop stirring, let it st...

Embodiment 2

[0063] Embodiment 2: the separation and recovery process after the synthetic imidacloprid of the present invention

[0064] 1. Concrete steps of reclaiming 2-nitroiminoimidazolidine

[0065] Step 1: Add 1000kg 2-nitroimidazolidine, 148kg NaOH and 2500L solvent dimethylformamide (DMF) to the synthesis kettle, drop 2-chloro-5 chloromethylpyridine solution (500kg 2-chloro-5 Chloromethylpyridine and 1500L DMF) carry out condensation reaction, the reaction liquid of synthesis is through adjusting acid, filter salt, transfer to DMF desolventizing kettle and distill at-0.095 MPa, 80 ℃, negative pressure distills DMF, when distillate volume is original Stop at 95% of the volume;

[0066] Step 2: When the temperature of the DMF precipitation kettle is lowered to below 30°C, add 4000L butanone, start stirring and heat up to 40°C, and continue to keep warm and stir for 60 minutes;

[0067] Step 3: Stop stirring, let it stand for 60 minutes, insert the pumping tube, pump out 3200-3400L ...

Embodiment 3

[0085] Embodiment 3: the separation and recovery process after the synthetic imidacloprid of the present invention

[0086] 1. Concrete steps of reclaiming 2-nitroiminoimidazolidine

[0087] Step 1: Add 1000kg 2-nitroimidazolidine, 148kg NaOH and 2500L solvent dimethylformamide (DMF) to the synthesis kettle, drop 2-chloro-5 chloromethylpyridine solution (500kg 2-chloro-5 Chloromethylpyridine and 1500L DMF) carry out condensation reaction, the reaction liquid of synthesis is through adjusting acid, filtering salt, transfers to DMF desolventizing kettle and distills at -0.1 MPa, 60-80 ℃, negative pressure distills DMF, when distillate volume Stop when it is 90% of the original volume;

[0088] Step 2: When the temperature of the DMF precipitation kettle is lowered to below 30°C, add 4000L of acetonitrile, start stirring and heat up to 50°C, and continue to keep warm and stir for 45 minutes;

[0089] Step 3: Stop stirring, let it stand for 45 minutes, insert the suction pipe, p...

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Abstract

The invention relates to the field of pesticide production process, in particular to a separation and recovery process after imidacloprid synthesis. The separation and recovery process of the invention comprises the following steps of: primarily distilling DMF (Dimethyl Formamide) from a reaction solution after a condensation reaction of 2-nitroaminoimidazoline, NaOH and 2-chloro-5 chloromethylpyridine; and adding an extractant to extract, wherein the lower substance is 2-nitroaminoimidazoline. The separation and recovery process of the invention also comprises the following steps of: evaporating the extracted supernatant; adding an eluent to crystallize and filtrate; washing the precipitate with the eluent; carrying out the mixed washing on the filtrate; distilling the solution until thevolume is 1 / 10 to 1 / 5; crystallizing; and filtrating under positive pressure to obtain the precipitate again. The separation and recovery process of the invention ensures that the recovery rate of the raw material of the 2-nitroaminoimidazoline is improved and the recovered 2-nitroaminoimidazoline can be directly used as a reaction raw material for realizing continuous reaction, shortens the production cycle, separates residential DMF, improves the imidacloprid purity and decreases the wastewater amount of a refining section.

Description

technical field [0001] The invention relates to the field of insecticide production technology, in particular to a separation and recovery process after imidacloprid is synthesized. Background technique [0002] Imidacloprid, whose chemical name is 1-(6-chloropyridin-3-pyridylmethyl)-N-nitroimidazolidin-2-ylamine, is a super-efficient neonicotinoid insecticide with broad-spectrum, high-efficiency, Low toxicity, low residue, pests are not easy to develop resistance, safe for humans, livestock, plants and natural enemies, and have multiple effects such as contact killing, stomach poisoning and systemic absorption. The normal conduction of the central nervous system is blocked after the pests are exposed to the pesticide, causing them to be paralyzed and dead. [0003] At present, the process of synthesizing imidacloprid is mainly dimethylformamide (DMF) imidacloprid condensation process, including hot water method and dichloroethane method. The synthesis process of the two me...

Claims

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Application Information

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IPC IPC(8): C07D401/06C07D233/52
Inventor 葛尧伦王开中韩先正侯进虎沈海伟赵学庆张立龙孔令乐陈龙龑
Owner SHANGDONG HAILIER CHEM
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