Synthesis and refining method of thiamethoxam intermediate 2-chloroallyl isothiocyanate

A technology of allyl thiocyanate and chloroisothiocyanate, which is applied in the field of synthesis and purification of thiamethoxam intermediate 2-chloroisothiocyanate, and can solve problems such as complicated operation, low yield and the like , to achieve the effect of simplifying the operation process, good yield and reducing cost

Inactive Publication Date: 2015-12-23
SHANDONG ACADEMY OF PESTICIDE SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] In order to solve the problems of low yield and cumbersome operation of the above-mentioned reaction system, the present invention provides a reaction system that enables nucleophilic substitution and rearrangement to proceed smoothly and thoroughly, and obtains 2-chloroallyl isothiocyanate in high yield. method

Method used

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  • Synthesis and refining method of thiamethoxam intermediate 2-chloroallyl isothiocyanate
  • Synthesis and refining method of thiamethoxam intermediate 2-chloroallyl isothiocyanate
  • Synthesis and refining method of thiamethoxam intermediate 2-chloroallyl isothiocyanate

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Embodiment 1

[0025] 1) Synthesis: Add 410g of process water, 293g of solid sodium thiocyanate and 370g of 2,3-dichloropropene into the reactor, stir, heat up to 84°C for reflux, and reflux for 12 hours. During the reaction, the temperature gradually rises to 112°C about. After the reaction finishes, add 250g dissolved water, the solid salt that generates is dissolved completely, and material temperature is cooled to 40 ℃, carry out static layering, separate 836g primary waste water and 478g2-allyl chloroisothiocyanate crude product A, The content is about 89%, and the crude yield is about 95.6%.

[0026] The experimental data of this synthesis step is shown in Table 1-1:

[0027] Table 1-1 Experimental data table

[0028] Material name Experiment feeding (g) 2,3-Dichloropropene 370 Sodium thiocyanate 293 process water 410 dissolved water 250

[0029] primary waste water 836 Allyl 2-Chloroisothiocyanate Crude A 478

[0030] 2)...

Embodiment 2

[0040] (1) With 2,3-dichloropropene and sodium thiocyanate as the reaction raw materials, in the presence of water, thiocyanate replaces chloride ions to generate allyl thiocyanate, and then regenerates from allyl thiocyanate Row to generate allyl 2-chloroisothiocyanate; the mass position of 2,3-dichloropropene and process water is 1:0.7; the molar ratio of 2,3-dichloropropene to sodium thiocyanate is 1:0.95 ; Reaction temperature is 50°C; Reaction time is 1 hour

[0041] (2) After the synthesis reaction is finished, the material is cooled, allowed to stand, and layered to obtain the crude product of allyl 2-chloroisothiocyanate;

[0042] (3) The crude product of allyl 2-chloroisothiocyanate obtained in step (2) is treated and refined through water removal to obtain the allyl 2-chloroisothiocyanate product; wherein the water removal process uses two Ethyl chloride and water are azeotroped to remove water. The mass ratio of dichloroethane and crude allyl 2-chloroisothiocyanate...

Embodiment 3

[0047](1) With 2,3-dichloropropene and sodium thiocyanate as the reaction raw materials, in the presence of water, thiocyanate replaces chloride ions to generate allyl thiocyanate, and then regenerates from allyl thiocyanate Row to generate allyl 2-chloroisothiocyanate; the mass position of 2,3-dichloropropene and water is 1:1.25; the molar ratio of 2,3-dichloropropene to sodium thiocyanate is 1:1.1; The reaction temperature is 120°C; the reaction time is 24 hours

[0048] (2) After the synthesis reaction is finished, the material is cooled, allowed to stand, and layered to obtain the crude product of allyl 2-chloroisothiocyanate;

[0049] (3) The crude product of allyl 2-chloroisothiocyanate obtained in step (2) is treated and refined through water removal to obtain the allyl 2-chloroisothiocyanate product; wherein the water removal process uses two Ethyl chloride and water are azeotroped to remove water. The mass ratio of dichloroethane and crude allyl 2-chloroisothiocyanat...

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Abstract

The invention discloses a preparation method of 2-chloroallyl isothiocyanate. The method includes: taking 2, 3-dichloropropene and sodium thiocyanate as reaction raw materials, in the presence of a solvent, replacing chloride ions with thiocyanate radicals to generate allyl thiocyanate, and then carrying out rearrangement reaction on allyl thiocyanate to generate 2-chloroallyl isothiocyanate; at the end of the reaction, conducting cooling, standing and layering on the material to obtain a 2-chloroallyl isothiocyanate crude product; and subjecting the 2-chloroallyl isothiocyanate crude product to dewatering treatment and refining, thus obtaining the2-chloroallyl isothiocyanate product. The method provided by the invention enables smooth and thorough nucleophilic substitution and rearrangement, and can achieve high yield.

Description

technical field [0001] The invention belongs to the field of preparation of nicotinic insecticides, and in particular relates to a method for synthesizing and refining thiamethoxam intermediate 2-allyl chloroisothiocyanate. Background technique [0002] Thiamethoxam is a neonicotinoid insecticide developed by Novartis in 1991. Its mechanism of action is similar to that of imidacloprid. It can selectively inhibit the nicotinic acid acetylcholinesterase receptor in the insect central nervous system, thereby blocking the insect central nervous system. Normal conduction, causing the pests to die when they appear paralyzed. Not only has contact killing, stomach poisoning, and systemic activity, but also has higher activity, better safety, wider insecticidal spectrum, fast action speed, and long-lasting effect. It replaces those with high toxicity to mammals. , a better variety of organic phosphorus, carbamate, and organochlorine insecticides with residues and environmental probl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C331/22
Inventor 李德军左伯军李旭坤李磊童佩剑侯波马新刚程圆杰申宝玉
Owner SHANDONG ACADEMY OF PESTICIDE SCI
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