76-05-1Relevant articles and documents
Enthalpies of Hydration of Alkenes. 1. The n-Hexenes
Wiberg, Kenneth B.,Wasserman, David J.
, p. 6563 - 6566 (1981)
Alkenes undergo a rapid reaction with trifluoroacetic acid containing 0.25 M trifluoroacetic anhydride in the presence of a strong acid catalyst.The enthalpies of trifluoroacetolysis of the five n-hexenes were determined and were corrected to the enthalpies corresponding to the formation of the equilibrium mixture of 2-hexyl trifluoroacetate and 3-hexyl trifluoroacetate.The enthalpy difference between the latter was determined by measuring the equilibrium constant as a function of temperature.The trifluoroacetolysis data may be combined with the measured enthalpies of formation of the alkenes to derive more precise values for the latter.The enthalpies of reaction of water, 2-hexanol, and 3-hexanol with the reaction solvent were determined, and when combined with the other data lead to enthalpies of hydration of the alkenes and the enthalpies of formation of the alcohols.
Kinetics of mass transfer of carbonyl fluoride, trifluoroacetyl fluoride, and trifluoroacetyl chloride at the air/water interface
George,Saison,Ponche,Mirabel
, p. 10857 - 10862 (1994)
The heterogeneous chemistry, on aqueous surfaces, of a series of acid halides, COF2, CF3COF, and CF3-COCl, was studied. The technique used consists of a low-pressure flow tube reactor in which a stream of monodisperse droplets interacts with the gaseous acid halide. The experiments, which were performed as a function of the initial pH of the droplets, temperature, and gas/liquid interaction time, yield low uptake coefficients in the range 5 × 10-4 to 5 × 10-3 and allow estimation of the product H.√k, where H is the Henry's law constant and k is the hydrolysis rate constant. The values reported here are 60, 60, and 350 M-atm-1 s- 1/2 for CF3COCl, CF3COF, and COF2, respectively, at 273 K. Separate values of H and k are also reported. The results show slightly different behavior between the chloride and the fluorides as a function of temperature. This study shows Henry's law and hydrolysis rate constants large enough that heterogeneous reactions on aqueous surfaces will limit the residence time of these species in the atmosphere.
Trifluoroselenoacetic acid, CF3C(O)SeH: Preparation and properties
Gomez Castano, Jovanny A.,Romano, Rosana M.,Beckers, Helmut,Willner, Helge,Della Vedova, Carlos O.
, p. 9972 - 9977 (2010)
The hitherto unknown trifluoroselenoacetic acid was prepared through the reaction of trifluoroacetic acid with Woollins' reagent. The compound was fully characterized by mass spectrometry, 1H, 19F, 77Se, and 13C NMR, UV-visible, IR and Raman spectroscopy, and the boiling point at 46 °C was estimated from the vapor pressure curve. An IR matrix isolation study revealed the presence of two different syn-anti and anti-syn conformers. The IR spectra of the two stereoisomers have been assigned, aided by DFT, and ab initio calculations. The UV photolysis of Ar matrix isolated CF3C(O)SeH yielded CO, OCSe, CF3SeH, and CHF3. Apart from CF3SeH, these products were also obtained by vacuum flash-pyrolysis (310 °C) of gaseous CF3C(O)SeH. Instead of CF3SeH, CF2Se, and HF were detected among the pyrolysis products. The different decomposition pathways of CF 3C(O)SeH are discussed.
N- vs O-protonation and the transannular substituent interaction in 8-(dimethylamino)-1-acetonaphthone
Schuster, Ingeborg I.,Freyer, Alan J.,Rheingold, Arnold L.
, p. 5752 - 5759 (2000)
Dynamic NMR measurements of 8-(dimethylamino)-1-acetonaphthone 1 in neutral solutions reveal a solvent dependency of the barrier to NMe group interchange similar to that reported for N,N-dimethylacetamide. Titrating 1 with TFA in solvents of varying donicities gives rise to equilibrium mixtures of N-protonated aminoketone 2 and the O-protonated transannular addition product 3, the interconversion rate of which is slow on the NMR time scale at ambient temperature. The preference for O- or N-protonation is medium-dependent, the amount of N-protonated 2 increasing with a decrease in the nucleophilicity of the solvent. The set of equilibria which govern the interconversion of 2 and 3 in the titration mixtures are identified and their equilibrium constants evaluated from the NMR data. X-ray analysis of the crystalline trifluoroacetate salt of O-protonated 3 indicates that the transannular N···CO bond of 3 is formed to an extent of only 80%. The equilibrium distribution of 2 and 3, paired with the tetrafluoroborate anion, depends on both the nucleophilicity and the polarity of the solvent. In PhNO2 the enthalpy change 3 → 2 amounts to 2.6 kcal/mol.
Degradation of phenyltrifluoromethylketone in water by separate or simultaneous use of TiO2 photocatalysis and 30 or 515 kHz ultrasound
Theron, Philippe,Pichat, Pierre,Guillard, Chantal,Petrier, Christian,Chopin, Thierry
, p. 4663 - 4668 (1999)
TiO2 photocatalysis and ultrasound are emerging technologies for the mineralization of pollutants in water. To further investigate these technologies and to assess whether advantages and synergy can be expected from their differences, phenyltrifluoromethylketone (PTMK) was selected as a test compound for pollutants generating CF3COOH, an undesirable final product. The PTMK first-order removal rate constant k was ca. 14 times higher when the ultrasound frequency was 515 kHz instead of 30 kHz for the same energy, and ca. 2.5 times higher when a TiO2 sample we synthesized was used instead of TiO2 Degussa P25. On simultaneous photocatalytic and ultrasonic treatment an increase in k by a factor between 1.4 and 1.9, depending on the TiO2 sample, was observed at 30 kHz but not at 515 kHz. On the basis of catalase enzymatic effect upon k, these observations are tentatively explained by a photocatalytic OH radical production from sonochemically formed H2O2, provided that the H2O2 residence time on TiO2 is sufficient. PTMK ultrasonic pyrolysis was demonstrated by product analysis. The amount of CF3COOH was ca. 8 times lower in sonicated solutions than in UV-irradiated TiO2 suspensions, for both frequencies and both TiO2 samples. Therefore, because of a higher k value, a high frequency ultrasonic (pre)treatment is preferable to minimize CF3COOH formation.
Decarbonylative Fluoroalkylation at Palladium(II): From Fundamental Organometallic Studies to Catalysis
Lalloo, Naish,Malapit, Christian A.,Taimoory, S. Maryamdokht,Brigham, Conor E.,Sanford, Melanie S.
supporting information, p. 18617 - 18625 (2021/11/16)
This Article describes the development of a decarbonylative Pd-catalyzed aryl-fluoroalkyl bond-forming reaction that couples fluoroalkylcarboxylic acid-derived electrophiles [RFC(O)X] with aryl organometallics (Ar-M′). This reaction was optimized by interrogating the individual steps of the catalytic cycle (oxidative addition, carbonyl de-insertion, transmetalation, and reductive elimination) to identify a compatible pair of coupling partners and an appropriate Pd catalyst. These stoichiometric organometallic studies revealed several critical elements for reaction design. First, uncatalyzed background reactions between RFC(O)X and Ar-M′ can be avoided by using M′ = boronate ester. Second, carbonyl de-insertion and Ar-RF reductive elimination are the two slowest steps of the catalytic cycle when RF = CF3. Both steps are dramatically accelerated upon changing to RF = CHF2. Computational studies reveal that a favorable F2C-H - -X interaction contributes to accelerating carbonyl de-insertion in this system. Finally, transmetalation is slow with X = difluoroacetate but fast with X = F. Ultimately, these studies enabled the development of an (SPhos)Pd-catalyzed decarbonylative difluoromethylation of aryl neopentylglycol boronate esters with difluoroacetyl fluoride.
The aliphatic ring-opening and SNAr substitution in the reactions of perfluorobenzocycloalkenones with K2CO3 in water and methanol
Zonov, Yaroslav V.,Wang, Siqi,Karpov, Victor M.,Mezhenkova, Tatyana V.
, (2021/07/28)
In the reactions with aqueous K2CO3, perfluorinated benzocyclobuten-1-one, 3-R-indan-1-ones and 4-R-tetralin-1-ones (R = F, C2F5) undergo selective cleavage of the СO–С(Ar) bond to yield (2,3,4,5-tetrafluorophen
Methods for producing a methanol precursor, methanol, and a methyl ester from methane in high purities
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Page/Page column 11; 12, (2021/06/02)
A method for producing a methanol precursor, methyl trifluoroacetate, having high-purity includes the steps of (a) preparing methyl bisulfate by mixing a catalyst with an acid solution comprising a sulfur-containing acid to provide a first mixture and supplying methane gas to the first mixture to prepare the methyl bisulfate; and (b) preparing methyl trifluoroacetate (CF3CO2CH3) by adding trifluoroacetic acid (CF3CO2H) to the first mixture including the methyl bisulfate to provide a second mixture and distilling the second mixture under heating to prepare, separate and purify the methyl trifluoroacetate (CF3CO2CH3). Methanol may be produced by adding water to the methyl trifluoroacetate (CF3CO2CH3). A methyl ester represented by Formula 2 below may be produced by adding a carboxylic acid represented by Formula 1 below to the methyl trifluoroacetate (CF3CO2CH3): R1CO2H??(1),where R1 is selected from C1-C10 alkyl groups, R1CO2CH3??(2),where R1 is as defined in Formula 1.
Oxidation of fluoroalkyl alcohols using sodium hypochlorite pentahydrate [1]
Kirihara, Masayuki,Suzuki, Katsuya,Nakakura, Kana,Saito, Katsuya,Nakamura, Riho,Tujimoto, Kazuki,Sakamoto, Yugo,Kikkawa, You,Shimazu, Hideo,Kimura, Yoshikazu
, (2021/02/05)
Fluoroalkyl alcohols are effectivity oxidized to the corresponding fluoroalkyl carbonyl compounds by reaction with sodium hypochlorite pentahydrate in acetonitrile in the presence of acid and nitroxyl radical catalysts. Although the reaction proceeded slower under a nitroxyl radical catalyst- free condition, the desired carbonyl compounds were obtained in high yields. For the reaction with fluoroalkyl allylic alcohols, the corresponding α,β-epoxyketone hydrates were obtained in high yields.
METHOD FOR PREPARING OXYSULPHIDE AND FLUORINATED DERIVATIVES IN THE PRESENCE OF AN ORGANIC SOLVENT
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Paragraph 0193-0195, (2019/04/05)
The present invention concerns a method for preparing an oxysulphide and fluorinated derivative of formula (III) Ea-SO3R (III) that comprises bringing a compound of formula (II) Ea-SOOR (II)—Ea representing the fluorine atom or a group having 1 to 10 carbon atoms chosen from the fluoroalkyls, the perfluoroalkyls and the fluoroalkenyls; and—R representing hydrogen, a monovalent cation or an alkyl group; into contact, in the presence of a polar aprotic organic solvent, with an oxidising agent.
