Synthesis method of 3, 4, 5, 6-tetrafluorophthalic acid

A technology of tetrafluorophthalic acid and tetrachlorophthalic hydrazide is applied in the field of synthesis of organic compound 3,4,5,6-tetrafluorophthalic acid, and can solve the problem of unfriendly environment and by-products. many problems, long reaction time, etc., to achieve the effects of broad production prospects, improved product yield, and simple post-processing

Inactive Publication Date: 2016-06-22
ZHEJIANG UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] 1. Using literature (Chemical Science and Technology Market, 2006 (07): 30-33), using tetrachlorophthalic anhydride as raw material, tetrafluorophthalic acid is obtained through imidization, fluorination, and sulfuric acid hydrolysis. Poor performance, many by-products, low yield, using sulfuric acid for hydrolysis reaction, the reaction time is about 15 to 40 hours, the production efficiency is low, and a large amount of waste acid is produced to pollute the environment
[0006] 2, adopt literature (JournaloftheChemicalSociety, 1965 (5): 3372), take tetrachlorophthalonitrile as raw material, obtain target product through fluorination, sulfuric acid hydrolysis, this synthetic method raw material source is limited, and hydrolysis reaction can produce nitrile-containing waste water , not friendly to the environment
[0008] In the existing preparation method, there is no bibliographical report of synthesizing the target product with phthalic hydrazide and its analogues as raw materials

Method used

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  • Synthesis method of 3, 4, 5, 6-tetrafluorophthalic acid
  • Synthesis method of 3, 4, 5, 6-tetrafluorophthalic acid
  • Synthesis method of 3, 4, 5, 6-tetrafluorophthalic acid

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] Embodiment 1, a kind of synthetic method of 3,4,5,6-tetrafluorophthalic acid, carries out following steps successively:

[0042] 1), add 16.2g (0.1mol) phthalohydrazide to 50mL oleum (SO 3 The mass fraction is 20%) and 50mL dilute hydrochloric acid (20wt%) in the mixed solution that forms, then add 0.16gKI catalyst and mix and stir, temperature control 50 ℃, control feed 0.3mol chlorine, reaction time 10 hours. The reaction solution after the complete chlorination was cooled (cooled to room temperature) to crystallize, filtered and dried (dried at 80° C. for 60 minutes) to obtain 28.3 g of white crystals of tetrachlorophthalic hydrazide, and the yield was 94.3% (based on o-phenyl Diformyl hydrazide), the content is 99.1%.

[0043] 2) Add 14.53g (0.25mol) of industrial potassium fluoride into a reaction flask containing 50mL of methanol, 50mL of toluene and 50mL of N,N-dimethylformamide mixed solution. The reaction device is equipped with a reflux tube, a thermometer an...

Embodiment 2

[0045] Embodiment 2, a kind of synthetic method of 3,4,5,6-tetrafluorophthalic acid, carries out following steps successively:

[0046] 1), add 16.2g (0.1mol) phthalohydrazide to 50mL fuming sulfuric acid (SO 3The mass fraction is 20%) and 100mL dilute hydrochloric acid (25wt%) mixed solution, then add 0.08gNaI catalyst and mix and stir, the temperature is controlled at 0°C, and 0.4mol chlorine gas is controlled to feed in, and the reaction time is 8 hours. The reaction solution after complete chlorination was cooled and crystallized, filtered and dried to obtain 27.8 g of white crystals of tetrachlorophthalic hydrazide, the yield was 92.7% (calculated as phthalic hydrazide), and the content was 99.0%.

[0047] 2) Add 29.1g (0.5mol) of industrial potassium fluoride into a reaction flask containing 50mL of methanol, 100mL of toluene and 50mL of N,N-dimethylacetamide mixed solution. The reaction device is equipped with a reflux tube, a thermometer and nitrogen replacement devic...

Embodiment 3

[0049] Embodiment 3, a kind of synthetic method of 3,4,5,6-tetrafluorophthalic acid, carries out following steps successively:

[0050] 1) Add 32.4g (0.2mol) phthalohydrazide to 50mL fuming sulfuric acid (SO 3 Mass fraction is 20%) and 150mL dilute hydrochloric acid (28wt%) in the mixed liquor, then add 0.08gI 2 The catalyst was mixed and stirred, the temperature was controlled at 0° C., 1.6 mol of chlorine gas was controlled to flow in, and the reaction time was 8 hours. The reaction liquid after complete chlorination was cooled and crystallized, filtered and dried to obtain 53.1 g of white crystals of tetrachlorophthalhydrazide, the yield was 88.6% (calculated as phthalhydrazide), and the content was 98.8%.

[0051] 2) Add 58.1g (1mol) of industrial potassium fluoride into a reaction flask filled with a mixed solution of 50mL of methanol, 50mL of toluene and 100mL of dimethyl sulfoxide. The reaction device is equipped with a reflux tube, a thermometer and a nitrogen replace...

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Abstract

The invention discloses a synthesis method of 3, 4, 5, 6-tetrafluorophthalic acid, comprising the following steps: (1) adding phthalylhydrazine into mixed liquid of fuming sulfuric acid and diluted hydrochloric acid, then adding a catalyst I into the mixed liquid and stirring the mixture, controlling the filling of chlorine, and carrying out a thermal reaction; (2) adding potassium fluoride into a reaction device containing methyl alcohol, methylbenzene and a solvent I, heating up and then stirring the mixture, and carrying out atmospheric distillation on reaction liquid to recover the methyl alcohol and the methylbenzene; after that, under the protection of nitrogen, adding the tetrachloro phthalylhydrazine prepared in the step (1) and a catalyst II into the product, heating up to 120-200 DEG C and carrying out a fluoridation reaction; (3) adding the tetrachloro phthalylhydrazine and sodium peroxide which are prepared in the step (2) into water, carrying out a hydrolysis reaction for 2-8 hours at the temperature of 10-50 DEG C, then adjusting the acidity of the obtained reaction liquid until the pH value of the reaction liquid is equal to 1-4, carrying out suction filtration and drying to obtain the tetrafluorophthalic acid.

Description

technical field [0001] The invention relates to a method for synthesizing organic compound 3,4,5,6-tetrafluorophthalic acid. Background technique [0002] 3,4,5,6-Tetrafluorophthalic acid, which has the molecular formula C 8 h 2 f 4 o 4 , whose structural formula is shown in S-1, and the pure product is a white granular crystalline solid. The compound is mainly used for pharmaceutical intermediates and intermediates for the synthesis of fluorine-containing aromatic chemicals. [0003] [0004] At present, the synthesis methods of 3,4,5,6-tetrafluorophthalic acid are as follows: [0005] 1. Using literature (Chemical Science and Technology Market, 2006 (07): 30-33), using tetrachlorophthalic anhydride as raw material, tetrafluorophthalic acid is obtained through imidization, fluorination, and sulfuric acid hydrolysis. Poor performance, many by-products, low yield, using sulfuric acid for hydrolysis reaction, the reaction time is about 15 to 40 hours, the production e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C63/68C07C51/00
CPCC07C51/00C07D237/32C07C63/68
Inventor 钱超时云龙高锐陈新志
Owner ZHEJIANG UNIV
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