769-39-1Relevant articles and documents
Method for synthesizing 2,3,5,6-tetrafluorophenol
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Paragraph 0023-0032, (2021/08/07)
The invention discloses a method for synthesizing 2,3,5,6-tetrafluorophenol, belonging to the field of fine chemical engineering. According to the invention, short-chain sodium aliphatate with large steric hindrance and pentafluorobenzoic acid are subjected to a reflux reaction in a polar solvent; after the reaction is finished, strong acid hydrolysis decarboxylation and steam distillation are performed; and a water vapor distillation product is rectified to obtain 2,3,5,6-tetrafluorophenol, the purity of 2,3,5,6-tetrafluorophenol is 99.8% or above, and the yield of 2,3,5,6-tetrafluorophenol is 88% or above. The method has the remarkable characteristics of simplicity and convenience in operation and small environmental pollution, and has a relatively good economic value in preparation of a 2,3,5,6-tetrafluorophenol product.
Preparation method 2, 3, 5, 6 - tetrafluoro-phenol
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Paragraph 0020; 0030-0033, (2020/08/09)
The invention discloses a method for preparing 2,3,5,6-tetrafluorophenol. The method comprises the following steps: enabling 2,3,4,5,6-pentafluorobenzoic acid as a raw material to react with inorganicalkali and a phase transfer catalyst in water so as to obtain 4-hydroxy-2,3,5,6-tetrafluorophenol, and performing decarboxylation, thereby obtaining 2,3,5,6-tetrafluorophenol. By adopting the 2,3,4,5,6-pentafluorobenzoic acid as the raw material, the cost of the raw material can be greatly reduced, no special or harsh reaction condition is needed, production equipment is not highly required, nospecial waste is generated, the intermittent is easy to separate, the preparation cost and the labor cost of production can be reduced, and the economic benefits can be increased.
Catalytic defluorination of perfluorinated aromatics under oxidative conditions using N-bridged diiron phthalocyanine
Colomban, Cédric,Kudrik, Evgenij V.,Afanasiev, Pavel,Sorokin, Alexander B.
supporting information, p. 11321 - 11330 (2014/11/07)
Carbon-fluorine bonds are the strongest single bonds in organic chemistry, making activation and cleavage usually associated with organometallic and reductive approaches particularly difficult. We describe here an efficient defluorination of poly- and perfluorinated aromatics under oxidative conditions catalyzed by the μ-nitrido diiron phthalocyanine complex [(Pc)Fe III(μ-N)FeIV(Pc)] under mild conditions (hydrogen peroxide as the oxidant, near-ambient temperatures). The reaction proceeds via the formation of a high-valent diiron phthalocyanine radical cation complex with fluoride axial ligands, [(Pc)(F)FeIV(μ-N)FeIV(F) (Pc+?)], which was isolated and characterized by UV-vis, EPR, 19F NMR, Fe K-edge EXAFS, XANES, and Kβ X-ray emission spectroscopy, ESI-MS, and electrochemical techniques. A wide range of per- and polyfluorinated aromatics (21 examples), including C6F6, C6F5CF3, C6F5CN, and C6F5NO2, were defluorinated with high conversions and high turnover numbers. [(Pc)FeIII(μ-N)Fe IV(Pc)] immobilized on a carbon support showed increased catalytic activity in heterogeneous defluorination in water, providing up to 4825 C-F cleavages per catalyst molecule. The μ-nitrido diiron structure is essential for the oxidative defluorination. Intramolecular competitive reactions using C6F3Cl3 and C6F3H 3 probes indicated preferential transformation of C-F bonds with respect to C-Cl and C-H bonds. On the basis of the available data, mechanistic issues of this unusual reactivity are discussed and a tentative mechanism of defluorination under oxidative conditions is proposed.
