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Synthetic method of 2,3,5,6-tetrafluoro-1,4-benzenedimethanol

A technology for terephthalimethanol and a synthesis method, which is applied in the field of synthesis of 2,3,5,6-tetrafluoro-1,4-terephthalenediethanol, can solve the problem of serious corrosion of production equipment, large environmental pollution, and process routes. It can reduce the consumption of raw materials, improve the environment, and reduce side reactions.

Active Publication Date: 2015-07-01
JIANGSU JIALONG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The purpose of the present invention is to address the shortcomings of the current domestic synthesis of 2,3,5,6-tetrafluoro-1,4-tere-phenylenedimethanol, which have long process routes, large equipment investment, large environmental pollution, and serious corrosion of production equipment. situation, a more convenient and reasonable, more suitable for industrial production of a synthetic method of 2,3,5,6-tetrafluoro-1,4-p-phenylenedimethanol

Method used

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  • Synthetic method of 2,3,5,6-tetrafluoro-1,4-benzenedimethanol
  • Synthetic method of 2,3,5,6-tetrafluoro-1,4-benzenedimethanol
  • Synthetic method of 2,3,5,6-tetrafluoro-1,4-benzenedimethanol

Examples

Experimental program
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Effect test

Embodiment 1

[0038] The synthetic method of 2,3,5,6-tetrafluoro-1,4-p-xylylenedimethanol comprises the following steps:

[0039] a) Preparation of 2,3,5,6-tetrafluoro-1,4-terephthalonitrile

[0040] In the dry reaction flask, add 500g DMF and 160g potassium fluoride, add 162g 2,3,5,6-tetrachloro-1,4-terephthalonitrile at room temperature under stirring, raise the temperature to 110°C, and control the reaction The temperature is 110-120°C, and the reaction is kept for 6 hours. After the reaction is completed, cool to 0°C and filter with suction, and wash the filter cake with water to obtain 2,3,5,6-tetrafluoro-1,4-terephthalonitrile-like white solid. Content ≥99%, mp 195~196.5°C (literature 193~195°C).

[0041] b) Preparation of dimethyl 2,3,5,6-tetrafluoro-1,4-terephthalate

[0042] Add 145g of 95% methanol to the reaction flask, stir and add 0.2g of the existing manganese dioxide catalyst, add 140g of 2,3,5,6-tetrafluoro-1,4-terephthalonitrile, heat up to reflux, slowly Add 345g of con...

Embodiment 2

[0054] Preparation of 2,3,5,6-tetrafluoro-1,4-p-xylylenedimethanol (comparative example)

[0055] a) Preparation of 2,3,5,6-tetrafluoro-1,4-terephthalonitrile

[0056] Add 620g DMF, 135g potassium fluoride, 135g 2,3,5,6-tetrachloro-1,4-terephthalonitrile, 2.5g hexadecyltrimethylammonium bromide in the dry reaction flask, stir Raise the temperature to 125-130°C, keep it warm for 4 hours, finish the reaction, distill under reduced pressure, recover 300g of DMF, add water to dilute the material in the bottle, filter with suction to obtain a yellow solid, and refine it to obtain off-white crystals, the yield is 78.5%, the content is 98.5%, mp 195~195.5℃.

[0057] b) Preparation of 2,3,5,6-tetrafluoro-1,4-terephthalic acid

[0058] Add 80g of water into the reaction bottle, stir and add 310g of sulfuric acid and 120g of glacial acetic acid, then add 150g of 2,3,5,6-tetrafluoro-1,4-terephthalonitrile, heat up to 140-142°C and keep it warm for 10 hours. After the reaction is compl...

Embodiment 3

[0063] Embodiment 3 (comparative example)

[0064] Preparation of 2,3,5,6-tetrafluoro-p-methoxybenzyl alcohol

[0065] Add toluene and 2,3,5,6-tetrafluoro-1,4-tere-phenylenedimethanol into the reaction flask, stir at 0°C and add dimethyl sulfate and liquid caustic dropwise at the same time, raise the temperature to 30°C after dropping, and stir to react After 2 hours, the reaction was completed, separated, washed with water until neutral, and a mixture of toluene and 2,3,5,6-tetrafluoro-p-methoxybenzyl alcohol was obtained. Triethylamine was added to the mixture, stirred and dropped at 0°C. Add dichlorochrysanthemum acid chloride, stir at room temperature for 4 hours after dropping, add water, wash with water until neutral, evaporate toluene to obtain perfluthrin.

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Abstract

The invention discloses a synthetic method of 2,3,5,6-tetrafluoro-1,4-benzenedimethanol. The synthetic method comprises the steps of: firstly, reacting 2,3,5,6-tetrafluoro-1,4-terephthalonitrile with potassium fluoride in the solvent DMF (Dimethyl Formamide) to obtain 2,3,5,6-tetrafluoro-1,4-terephthalonitrile; secondly, carrying out an alcoholysis reaction between 2,3,5,6-tetrafluoro-1,4-terephthalonitrile and methanol / water in excessive sulfuric acid medium to obtain dimethyl 2,3,5,6-tetrafluoro-1,4-terephthalate through one step; thirdly, dropwise adding the aqueous solution of potassium borohydride to the previous reactant to arouse an ester reduction reaction in water as the solvent in the presence of a phase transfer catalyst, thereby obtaining the crude product 2,3,5,6-tetrafluoro-1,4-benzenedimethanol; finally, refining and purifying to obtain refined 2,3,5,6-tetrafluoro-1,4-benzenedimethanol.

Description

technical field [0001] The invention belongs to the field of pesticide chemical industry, and in particular relates to a synthesis method of 2,3,5,6-tetrafluoro-1,4-tere-phenylenedimethanol. Background technique [0002] 2,3,5,6-tetrafluoro-1,4-tere-phenylenedimethanol is an important intermediate in the synthesis of pyrethroid pesticides such as tefluthrin and perfluthrin. Its structural formula is as follows: [0003] [0004] Its disclosed synthetic method is listed as follows: [0005] 1. Using hexafluorobenzene as the starting material: [0006] Using hexafluorobenzene as the starting material, 2,3,5,6-tetrafluoro-1,4-tere-phenylenedimethanol was obtained through five steps of methylation, bromination, chlorination, acyl chloride and reduction. [0007] [0008] This route has long steps, uses expensive methyllithium, and has a low synthesis yield, which is not suitable for industrial production. [0009] 2. Using terephthalic acid as raw material: [0010] A...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C33/46C07C29/147
CPCC07C29/147C07C67/22C07C253/30C07C33/46C07C255/51C07C69/82
Inventor 王泽华沈中泽
Owner JIANGSU JIALONG CHEM
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