- Preparation method of fluorine-containing carboxylic acid
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The invention discloses a preparation method of fluorine-containing carboxylic acid. The method comprises the following steps: reacting fluorine-containing carboxylate used as a raw material with an acylating chlorination reagent to obtain a corresponding mixture of fluorine-containing acyl chloride and fluorine-containing anhydride, and hydrolyzing and drying the mixture of fluorine-containing acyl chloride and fluorine-containing anhydride to obtain high-purity fluorine-containing carboxylic acid. The method provided by the invention is suitable for post-treatment of fluorine-containing carboxylic acid prepared by a fluorine-containing olefin (monoolefine, diene, cycloolefin and the like) oxidation method, replaces the traditional strong acid acidification and ether continuous extractionprocess, and is simpler, more convenient and more applicable; and the method can also be used for recovering and purifying a fluorine-containing carboxylate emulsifier. The purity of the fluorine-containing carboxylic acid prepared by the method can reach 98% or above.
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Paragraph 0046
(2020/07/12)
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- A fluorous-assisted synthesis of oligosaccharides using a phenyl ether linker as a safety-catch linker
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We report on the fluorous-assisted synthesis of oligosaccharides using a phenyl ether linker. The phenyl ether linker is stable under both acidic and basic conditions but can be cleaved under mildly acidic conditions after reduction to a vinyl ether. The utility of the method was demonstrated by the synthesis of a trisaccharide. A protected trisaccharide with a light-fluorous tag was directly prepared by one-pot glycosylation using three building blocks that contained a building block with a light-fluorous tag though a phenyl ether. A Birch reduction of the trisaccharide provided a fully deprotected trisaccharide with the fluorous tag attached through a vinyl ether, which was easily purified by solid-phase extraction. The tag was cleaved from the sugar portion by treatment with 3% TFA in MeOH.
- Tanaka, Hiroshi,Tanimoto, Yosuke,Kawai, Tetsuya,Takahashi, Takashi
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experimental part
p. 10011 - 10016
(2012/02/05)
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- Multiple pathways in cyclodextrin-catalyzed hydrolysis of perfluoroalkylamides
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The hydrolysis of p-nitroanilide of perfluoroalkanoic acids, CF3(CF2)nCO-, with n = 1, 2, 3, 5, 6, and 7, 1a-f, was studied in the presence of β-cyclodextrin (CD). All reactions were catalyzed by CD through the formation of a 1:1 and 1:2 inclusion complexes. The association equilibrium constants for the 1:1 complexes were dependent on the number of carbons of the fluoroalkyl chain, whereas those of the 1:2 complexes were almost independent. These results indicate that, in the former case, the perfluoroalkyl chain is included, while in the latter, the CD unit encloses the aryl ring. For compounds 1a,b both complexes were more reactive than the substrate itself. The ratio of the reaction of complexed to uncomplexed substrate had its highest value for 1a in the case of the 1:1 complex, and for 1b, the 1:2 complex. This is attributed to the geometry of the complexes. Although compounds 1c-e reacted at the same rates in the free or 1:1 complexed form, CD accelerated the reactions because of an increase of the pKa of the substrate, which results in a higher concentration of the neutral reactive substrate at the same pH. Compound 1f formed aggregates even at 10-6 M concentration, and CD-induced deaggregation resulted in catalysis of the reaction.
- Granados, Alejandro,De Rossi, Rita H.
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p. 3690 - 3696
(2007/10/02)
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- REACTIONS OF PERFLUOROACYL FLUORIDES WITH COMPLEXES OF ALUMINUM HALIDES
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The occurrence of halogenodefluorination reactions under the influence of AlHlg3 is explained by the high strength of the Al-F bond that forms.However, thermodynamically stable complexes of perfluoroacyl halides and aluminum halides prevent their full conversion.By substituting the AlHlg3 by the tetrahalogenoaluminates of metals of groups I and II it is possible to replace the F atom by the atoms of other halogens with quantitative yields.A nucleophilic substitution mechanism, accompanied by rearrangement of the intermediate, is proposed for this reaction.The reactivity of the MAlHlg4 does not depend on the nature of the halogen and is determined by the crystal lattice energy.With the AlHlg3-alkyl halide system as halogenodefluorinating agent it is possible to synthesize perfluoroacyl halides with high yields with the reagents in the stoichiometric ratio.The catalytic effect of the alkyl halides is explained by the displacement of the equilibrium RFCOHlg*AlHlg3 ->FCOHlg + AlHlg3 toward the formation of the final products.
- Bil'dinov, I. K.,Podsevalov, P. V.,Deev, L. E.
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p. 1915 - 1919
(2007/10/03)
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- PYROLYTIC REACTIONS OF PERFLUORINATED CARBOXYLIC ACID HALIDES
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Unlike other acyl halides, perfluoroacyl fluorides only enter into reaction with polar reagents.Perfluoroacyl fluorides, perfluoroacyl bromides, and perfluoroacyl iodides are smoothly decarbonylated at active carbon at elevated temperatures.In the absence of the active carbon the perfluoroacyl fluorides react with halogens, polyhalogenoalkanes, and iodoperfluoroalkanes with the formation of the corresponding halogenoperfluoroalkanes or their mixtures with perfluoroacyl halides; the low yields of the iodoperfluoroalkanes in the reaction of perfluoroacyl fluorides withiodine are explained by their ability to act themselves as reagents in these processes.The catalytic properties of active carbon are due to its ability to transfer electrons to the molecules of the adsorbed reagent and to hold the reaction particles on the surface; graphite and nickel also have specific catalytic activity.
- Podsevalov, P. V.,Bil'dinov, I. K.,Rychkov, M. L.,Deev, L. E.,Igumnov, S. M.
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p. 1269 - 1273
(2007/10/02)
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- SYNTHESES OF PERFLUOROALKYL N-POLYETHOXYLATED AMIDES
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Monodisperse perfluoroalkyl N-polyethoxylated amides, CnF2n+1CONH(CH2CH2O)mH, with n = 6, 7, 8 and 9 and m = 2, 3, and 4 are potential nonionic fluorinated surfactants.The syntheses of these comounds are described.
- Afzal, Jalees,Fung, B. M.,O'Rear, Edgar A.
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p. 385 - 394
(2007/10/02)
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