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Synthesis method of 3,4-dichlorobenzonitrile

The technology of a dichlorobenzonitrile and a synthesis method, which is applied in the preparation of pharmaceutical intermediates and the field of pesticides, can solve the problems of high price, rare starting materials, large supply of raw materials, etc., and achieves low cost of raw materials, mild and controllable reaction conditions, and low reaction conditions. short step effect

Active Publication Date: 2018-04-17
ZHEJIANG LINJIANG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] (3) One uses 3,4-dichlorobenzaldehyde as the starting material to form an oxime with hydroxylamine hydrochloride, and then dehydrates to generate 3,4-dichlorobenzonitrile, but the starting material is very rare and expensive
The above-mentioned synthetic techniques have their own characteristics, but there are certain shortcomings. The most important problem is that there is a big problem in the supply of raw materials. Therefore, a new method for the synthesis of 3,4-dichlorobenzonitrile is developed.

Method used

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  • Synthesis method of 3,4-dichlorobenzonitrile
  • Synthesis method of 3,4-dichlorobenzonitrile
  • Synthesis method of 3,4-dichlorobenzonitrile

Examples

Experimental program
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Effect test

Embodiment 1

[0033] (1) Bromination

[0034] Mix 26.2g of 1,2-dichlorobenzene with 2.75g of iron powder, heat to 45°C, slowly add 26g of bromine dropwise at a rate of 0.2mL / min, keep the reaction for 2 hours after the dropwise addition, and add sodium sulfite solution after the reaction is completed Wash with dichloromethane, get 41.6g of crude product after precipitation, containing 5.5% of 1,2-dichlorobenzene in the crude product, 2.1% of isomer 2,3-dichlorobromobenzene, high boiling (mainly dibromo or Polybrominated products, the same below) 0.6%, rectification, collect -0.09 ~ -0.1MPa 100 ~ 110 ℃ fraction recovery, collect -0.09 ~ -0.1MPa 160 ~ 165 ℃ fraction, that is, 3,4- 33.2 g of refined dichlorobromobenzene, the purity of 3,4-dichlorobromobenzene is 98.5%, and the molar yield is 90.3%.

[0035] (2) Cyanide

[0036] Mix and heat 5.4g cuprous cyanide, 0.1g L-proline and 25g DMF to 128°C, add dropwise 3,4-dichlorobromobenzene diluent (11.3g 3,4-dichlorobromobenzene and 10g DMF Mix...

Embodiment 2

[0038] (1) Bromination

[0039] Mix 26.2g of 1,2-dichlorobenzene with 2.75g of iron powder, heat to 75°C, slowly add 26g of bromine dropwise at a rate of 0.25mL / min, keep the reaction for 2 hours after the dropwise addition, and add sodium sulfite solution after the reaction is completed Extract and wash with dichloromethane, get 41.3g of crude product after desolvation, the crude product contains 4.8% of 1,2-dichlorobenzene, 2.0% of isomer 2,3-dichlorobromobenzene, high boiling 5.2%, rectification, collection -0.09~-0.1MPa 100~110℃ distillate recovery and apply mechanically, collect -0.09~-0.1MPa 160~165℃ distillate to obtain 31.5g of 3,4-dichlorobromobenzene refined product, 3,4-dichlorobromobenzene The purity of benzene is 98.3%, and the molar yield is 85.7%.

[0040] (2) Cyanide

[0041] Mix and heat 5.4g cuprous cyanide, 0.1g L-proline and 25g DMF to 150°C, add dropwise 3,4-dichlorobromobenzene diluent (11.3g 3,4-dichlorobromobenzene and 10g DMF Mixed solution of the m...

Embodiment 3

[0043] (1) Bromination

[0044] Mix 26.2g of o-dichlorobenzene and 0.59g of ferric chloride, heat to 45°C, slowly add 26g of bromine dropwise at a rate of 0.3mL / min, keep the reaction for 2 hours after the dropwise addition, after the reaction, add sodium sulfite solution and Dichloromethane was extracted and washed, and 41.1g of crude product was obtained after precipitation. The crude product contained 5.0% of 1,2-dichlorobenzene, 1.0% of isomer 2,3-dichlorobromobenzene, and 2.6% of high boiling point. It was rectified and collected- 0.09~-0.1MPa 100~110℃ distillate recovery, collect -0.09~-0.1MPa 160~165℃ distillate to obtain 33.1g of 3,4-dichlorobromobenzene refined product, 3,4-dichlorobromobenzene The purity is 98.5%, and the molar yield is 90.0%.

[0045] (2) Cyanide

[0046] Mix and heat 5.4g cuprous cyanide, 0.1g 1,10-phenanthroline hydrate and 25g DMF to 128°C, add dropwise 3,4-dichlorobromobenzene diluent (11.3g 3,4-dichlorobromobenzene mixed solution with 10g DM...

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Abstract

The invention discloses a synthesis method of 3,4-dichlorobenzonitrile. The synthesis method comprises the following steps of (1) adopting 1,2-dichlorobenzene as a raw material, adding a catalyst A, rising the temperature, then dropwise adding bromine, carrying out heat insulating reaction after the dropwise adding is finished, and carrying out aftertreatment to obtain 3,4-dichlorobromobenzene; (2) after mixing cuprous cyanide, a catalyst B and a solvent, dropwise adding 3,4-dichlorobromobenzene diluent after rising the temperature, carrying out heat insulating reaction after the dropwise adding is finished, and carrying out aftertreatment to obtain the 3,4-dichlorobenzonitrile. The synthesis method disclosed by the invention has the beneficial effects that the 1,2-dichlorobenzene is adopted as the raw material, and after two-step reaction of bromination and cyaniding, the 3,4-dichlorobenzonitrile is obtained, the molar yield can reach 85% or above and the purity is greater than or equal to 98%. The synthesis method disclosed by the invention is low in raw-material cost so as to be suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of preparation of pesticides and pharmaceutical intermediates, and in particular relates to a synthesis method of 3,4-dichlorobenzonitrile. Background technique [0002] 3,4-Difluorobenzonitrile is an important intermediate for the preparation of the herbicide cyhalofop-ethyl. This herbicide has high efficiency, low toxicity and low residue, is very safe to rice crops and has excellent selectivity to control gramineous weeds. And 3,4-dichlorobenzonitrile is the raw material of synthetic 3,4-difluorobenzonitrile, so 3,4-dichlorobenzonitrile has larger application value in the pesticide field, and its synthetic method is more and more accepted by people. focus on. [0003] Specifically, there are many synthetic methods for 3,4-dichlorobenzonitrile, which can be divided into the following types according to different starting materials: [0004] (1) One uses 3,4-dichlorotoluene as a raw material to synthesize 3,4-dichl...

Claims

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Application Information

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IPC IPC(8): C07C253/14C07C255/50
CPCC07C17/12C07C253/14C07C255/50C07C25/02
Inventor 易苗吴文良杨江宇王涛王启军
Owner ZHEJIANG LINJIANG CHEM
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