652-03-9Relevant articles and documents
POLYHALOAROMATICS. PART II. SYMTHESIS OF OCTAFLUORO-1,3-DIHYDRO-ISOBENZOFURAN AND ITS CONVERSION TO TETRAFLUOROTEREPHTHALIC ACID
Dmowski, Wojciech,Wielgat, Jerzy
, p. 241 - 246 (1988)
A high yield preparation of the title compound via treament of 4,5,6,7-tetrachloro-1,1,3,3-tetrafluoro-1,3-dihydroisobenzofuran with potassium fluoride in sulpholane is described.Hydrolysis of octafluoro-1,3-dihydroisobenzofuran with concentrated sulphuric acid provides a new and efficient route to tetrafluoroterephthalic acid.
Carbonylation of Polyfluorobenzocyclobutenones in a SbF5 Medium
Zonov, Ya. V.,Karpov,Mezhenkova
, p. 1103 - 1111 (2019/10/14)
The carbonylation of perfluoro-2-R-benzocyclobutenones (R = F, CF3, C2F5, C6F5) in a CO-SbF5 system is accompanied by transformations of the four-membered cycle in the substrate to form polyfluorinated 1H-isochromene derivatives. The reaction of perfluoro-2-R-benzocyclobutenes (R = F, CF3, C2F5) with (CF3CO)2O or CF3COOH in a SbF5 medium in a sealed ampule involves formation of polyfluorobenzocyclobutenones and their carbonylation under the reaction conditions.
Synthesis method of 3, 4, 5, 6-tetrafluorophthalic acid
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Paragraph 0036; 0060, (2016/11/21)
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.