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Method for preparing 2-chloro-4-fluorobenzene nitrile

A technology of fluorobenzonitrile and nitrobenzonitrile, which is applied in the field of preparing 2-chloro-4-fluorobenzonitrile, can solve the problems of long synthesis steps, environmental pollution, and low yield, and achieve no pollution, easy-to-obtain raw materials, The effect of high reaction selectivity

Inactive Publication Date: 2009-06-17
ZHANGJIAGANG HUASHENG CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The structural formula of 2-chloro-4-fluorobenzonitrile is: Its traditional synthetic methods include direct fluorination of 2-chlorobenzene cyanide, diazotization of 2-chloro-4-nitrobenzene cyanide and replacement with fluorine. These preparation methods generally have long synthesis steps and low yields. Disadvantages, only about 50% and 60% selectivity, accompanied by a large amount of solid and liquid waste, also caused serious environmental pollution

Method used

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  • Method for preparing 2-chloro-4-fluorobenzene nitrile
  • Method for preparing 2-chloro-4-fluorobenzene nitrile
  • Method for preparing 2-chloro-4-fluorobenzene nitrile

Examples

Experimental program
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Effect test

Embodiment 1

[0022] In a three-necked flask containing 120 g of dimethylacetamide and 58 g of potassium fluoride, add 183 g of 2-chloro-4-nitrobenzonitrile and 2.4 g of catalyst tetraphenyl bromide under stirring, and react at 100-110 °C for 8 ~10h. The solvent dimethylacetamide was distilled off under reduced pressure, the residue was extracted with cyclohexane, and the composition of the extract was analyzed by GC / MS. The extract was rectified under reduced pressure, and 133 g of fractions at 100-120°C / 10Pa were collected and passed through GC. / MS mass spectrometry, m / z: 155.56, proved to be Molecular ion characteristic fragments are measured with a gas chromatograph (GC-2014, purchased from Shimadzu company), the content of 2-chloro-4-fluorobenzonitrile in the fraction is 99.2538%, and the content of 2-chloro-4-fluorobenzonitrile product The yield was 85.26%.

Embodiment 2

[0024] In a three-necked flask containing 714g of dimethyl sulfoxide and 174g of potassium fluoride, add 183g of 2-chloro-4-nitrobenzonitrile and 18g of catalyst tetraethylphosphorous chloride under stirring, and react at 130-150°C for 5 ~8h. The solvent dimethyl sulfoxide was distilled off under reduced pressure, the residue was extracted with cyclohexane, and the composition of the extract was analyzed by GC / MS. The extract was rectified under reduced pressure, and 126 g of fractions at 100-120°C / 10Pa were collected and passed through GC. / MS mass spectrometry, m / z: 155.56, proved to be Molecular ion characteristic fragments are measured with a gas chromatograph (GC-2014, purchased from Shimadzu company), and the content of 2-chloro-4-fluorobenzonitrile in the fraction is 99.3687%, and the content of 2-chloro-4-fluorobenzonitrile product is The yield was 80.77%.

Embodiment 3

[0026] In a three-neck flask filled with 500g of dibutylacetamide and 87g of potassium fluoride, add 330g of 2-chloro-4-nitrobenzonitrile and 4g of catalyst tetraphenylbromophosphorus under stirring, and react at 130°C for 5 to 8 hours . The solvent dibutylacetamide was distilled off under reduced pressure, the residue was extracted with cyclohexane, and the composition of the extract was analyzed by GC / MS. The extract was rectified under reduced pressure, and 228 g of fractions at 100-120°C / 10Pa were collected and passed through GC. / MS mass spectrometry, m / z: 155.56, proved to be Molecular ion characteristic fragments are measured with a gas chromatograph (GC-2014, purchased from Shimadzu company), and the content of 2-chloro-4-fluorobenzonitrile in the fraction is 99.0327%, and the content of 2-chloro-4-fluorobenzonitrile product The yield was 81.05%.

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Abstract

The invention provides a method for preparing 2-chloro-4-fluorobenzonitrile. The method comprises the following steps: using 2-chloro-4-nitrobenzonitrile and potassium fluoride as raw materials and dialkylacetamide or dialkyl sulfoxide as a solvent to generate a reaction mixture containing the 2-chloro-4-fluorobenzonitrile at a certain temperature by adopting a quaternary alkylphosphonium salt as a catalyst; the reaction mixture adopts a saturated alkane extraction method; and an extraction liquid is rectified at the reduced pressure to obtain the required product 2-chloro-4-fluorobenzonitrile. The method has the advantages that the process route is simple; the raw materials are accessible and cheap, do not have severe toxicity, have strong stability, and do not pollute the environment; the purity of the product 2-chloro-4-fluorobenzonitrile is more than 99 percent, and yield of the product is over 80 percent; and high reaction selectivity reaches over 90 percent.

Description

technical field [0001] The invention relates to a method for preparing 2-chloro-4-fluorobenzonitrile. Background technique [0002] Fluorine-containing aromatic compounds are important pharmaceutical and pesticide intermediates. They have high fat solubility and hydrophobicity, which can promote their absorption and delivery speed in organisms and change their physiological effects. Fluorine-containing aromatic compounds have the characteristics of less dosage, low toxicity, high efficacy, and strong metabolism in the field of medicine and pesticides, which makes them account for an increasing proportion of medicines and pesticides. The structural formula of 2-chloro-4-fluorobenzonitrile is: Its traditional synthetic methods include direct fluorination of 2-chlorobenzene cyanide, diazotization of 2-chloro-4-nitrobenzene cyanide and replacement with fluorine. These preparation methods generally have long synthesis steps and low yields. Disadvantages, only about 50% and 60%...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C255/50C07C253/30
Inventor 张先林刘东杨志勇林刚李伟峰
Owner ZHANGJIAGANG HUASHENG CHEM CO LTD
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