- Radical C?H Trifluoromethoxylation of (Hetero)arenes with Bis(trifluoromethyl)peroxide
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Trifluoromethoxylated (hetero)arenes are of great interest for several disciplines, especially in agro- and medicinal chemistry. Radical C?H trifluoromethoxylation of (hetero)arenes represents an attractive approach to prepare such compounds, but the high cost and low atom economy of existing .OCF3 radical sources make them unsuitable for the large-scale synthesis of trifluoromethoxylated building blocks. Herein, we introduce bis(trifluoromethyl)peroxide (BTMP, CF3OOCF3) as a practical and efficient trifluoromethoxylating reagent that is easily accessible from inexpensive bulk chemicals. Using either visible light photoredox or TEMPO catalysis, trifluoromethoxylated arenes could be prepared in good yields under mild conditions directly from unactivated aromatics. Moreover, TEMPO catalysis allowed for the one-step synthesis of valuable pyridine derivatives, which have been previously prepared via multi-step approaches.
- Dix, Stefan,Golz, Paul,Schmid, Jonas R.,Riedel, Sebastian,Hopkinson, Matthew N.
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supporting information
p. 11554 - 11558
(2021/07/09)
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- From hypochlorites to perfluorinated dialkyl peroxides
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The synthesis and characterization of the new perfluorinated hypochlorite, undecafluoro-tert-pentyl hypochlorite, (C2F5)(F3C)2COCl, is reported. Its gas-phase infrared, UV/Vis and NMR spectra have been recorded and its spectroscopic properties are discussed and compared with quantum-chemical predictions and those of other known perfluorinated hypochlorites such as RFOCl [RF = F3C, (F3C)3C, (C2F5)(F3C)2C]. A synthetic route to otherwise difficult to access perfluorinated dialkyl peroxides, RFOORF, is also provided by low-temperature photolysis of the corresponding hypochlorite.
- Nissen, Jan H.,Wickemeyer, Lucas,Stüker, Tony,Steinhauer, Simon,Beckers, Helmut,Riedel, Sebastian
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- Synthesis and properties of trifluoromethoxyl fluoroformyl anhydride, CF3OC(O)OC(O)F
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In the present work the synthesis of the trifluoromethoxyl fluoroformyl anhydride is presented for the first time. Two strategies were employed to obtain CF3OC(O)OC(O)F: the thermal decomposition of CF 3OC(O)OOOC(O)F in excess of CO, and the reaction between CF 3OC(O)OOC(O)F, FC(O)OOC(O)F and CO. A mechanism was proposed taking into account reaction rates and thermal stability of the intermediates. DFT calculations at B3LYP/6-311+G* level were used to explore the conformational space of this molecule and the relative populations of conformers at room temperature, and to simulate the experimental vibrational spectrum. This molecule completes the family of the asymmetric oxygen bonded acyl compounds CF3OC(O)OxC(O)F with x = 1-3.
- Manetti, Martín M.,Argüello, Gustavo A.,Paci, Maxi A. Burgos
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experimental part
p. 16 - 20
(2012/10/08)
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- GASEOUS DIELECTRICS WITH LOW GLOBAL WARMING POTENTIALS
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A dielectric gaseous compound which exhibits the following properties: a boiling point in the range between about ?20° C. to about ?273° C.; non-ozone depleting; a GWP less than about 22,200; chemical stability, as measured by a negative standard enthalpy of formation (dHf0); a toxicity level such that when the dielectric gas leaks, the effective diluted concentration does not exceed its PEL; and a dielectric strength greater than air.
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- The use of perfluoroalkyl hypofluorites for an efficient synthesis of perfluorinated ethers characterized by low Ostwald coefficient
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In the reaction between perfluoroolefins and perfluoroalkylhypofluorites the existence of two different free radical reaction mechanisms is demonstrated by the presence of characteristic byproducts. These kinetic schemes can be experimentally controlled b
- Navarrini, Walter,Venturini, Francesco,Sansotera, Maurizio,Ursini, Maurizio,Metrangolo, Pierangelo,Resnati, Giuseppe,Galimberti, Marco,Barchiesi, Emma,Dardani, Patrizia
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p. 680 - 685
(2008/12/22)
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- Reaction between carbon dioxide and elementary fluorine
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Reactions between carbon dioxide and fluorine were examined at temperatures of 303-523 K under various pressure and mixture ratios of both gases. Reactions were carried out similarly under the existence of NaF, CsF and EuF3. After the reaction, fluorine was removed and the reaction products were analyzed using FT-IR, GC/FT-IR and GC/MS. The major products were CF3OF, COF2, CF4 and CF2(OF)2. The best yield of COF2 was 11.1% under the reaction condition of CO2/F2 = 76 kPa/76 kPa with temperature of 498 K for 72 h in a direct reaction. The formation rate of COF2 in the direct reaction was estimated as 0.232 dm3 mol-1 h-1 under the reaction conditions of CO2/F2 = 76 kPa/76 kPa, at 498 K. In the presence of CsF, it was estimated as 1.88 dm3 mol-1 h-1 at CO2/F2 = 76 kPa/76 kPa at 498 K. The activation energy of the COF2 formation in the direct reaction was estimated as 45.7 kJ mol-1 at CO2/F2 = 76 kPa/76 kPa at 498 K. In addition, 24.2 and 38.9 kJ mol-1 were evaluated at CO2/F2 = 76 kPa/76 kPa at 498 K, respectively, in the presence of CsF and EuF3.
- Hasegawa, Yasuo,Otani, Reiko,Yonezawa, Susumu,Takashima, Masayuki
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- Preparation of high purity fluorinated peroxides
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High-purity fluorinated peroxides are prepared in a simplified process in which carbonyl fluoride is reacted with a hypofluorite to produce a gaseous reaction product which is essentially free of unreacted hypofluorite; unreacted carbonyl fluoride and by productsare removed from the gaseous reaction product under gas phase conditions; and then the fluorinated peroxideis collected in gas phase.
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Page/Page column 5
(2008/06/13)
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- Preparation of high purity fluorinated peroxides
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This invention is directed to an improvement in a process for producing high-purity fluorinated peroxides typically formed by the reaction of a carbonyl fluoride with a hypofluorite. The improvement resides in a simplified process for the synthesis and recovery of high purity fluorinated high purity peroxide product and comprises the steps: (a) reacting the carbonyl fluoride with the hypofluorite under conditions such that a gaseous reaction product comprised of the fluorinated peroxide and unreacted carbonyl fluoride which is essentially free of unreacted hypofluorite is formed; (b) removing unreacted carbonyl fluoride and by products from the gaseous reaction product under gas phase conditions thereby generating a gaseous product stream containing the fluorinated peroxide; and then, (c) collecting the fluorinated peroxide from step (b) in gas phase.
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Page/Page column 3
(2008/06/13)
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- Kinetics of the thermal decomposition of bis(trifluoromethyl) peroxydicarbonate, CF3OC(O)OOC(O)OCF3
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Thermal decomposition of bis(trifluoromethyl) peroxydicarbonate has been studied. The mechanism of decomposition is a simple bond fission, homogeneous first-order process when the reaction is carried out in the presence of inert gases such as N2 or CO. An activation energy of 28.5 kcal mol-1 was determined for the temperature range of 50-90°C. Decomposition is accelerated by nitric oxide because of a chemical attack on the peroxide forming substances different from those formed with N2 or CO. An interpretation on the influence of the substituents in different peroxides on the O-O bond is given.
- Burgos Paci, Maximiliano A.,Argueello, Gustavo A.,Garcia, Placido,Willner, Helge
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- Kinetic study of the reactions of CF3O2 radicals with Cl and NO
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Kinetic studies of the reactions CF3O2 + Cl and CF3O2 + NO were performed at room temperature in the gas phase using the discharge flow mass spectrometric technique (DFMS). The reactions were investigated under pseudo- first-order conditions with Cl or NO in large excess with respect to the CF3O2 radicals. The rate constant for the reaction CF3O2 + NO was measured at 298 K and the value of (1.6 ± 0.3) x 10-11 cm3 molecule-1 s-1 is in very good agreement with all previous values. For the reaction CF3O2 + Cl, we obtain a rate constant at 298 K of (4.2 ± 0.8) x 10-11 cm3 molecule-1 s-1 in excellent agreement with the only published value. Product analysis shows that this reaction occurs via the major reaction pathway CF3O2 + Cl → CF3O + ClO at room temperature. In addition, an ab initio theoretical study was performed to gain insights on the different postulated reaction pathways. There is a significant disagreement between experimental and ab initio values recommended for the formation enthalpies of CF2O, CF3O and related molecules produced in this system. Consequently, we provide self-consistent values of enthalpies based on isodesmic reactions for the CF3O2 + Cl reaction system using the G2, G2(MP2) and CBS-Q methods. These values are also compared with BAC-MP4 heats of formation calculated in this work.
- Louis, Florent,Burgess Jr., Donald R.,Rayez, Marie-Therese,Sawerysyn, Jean-Pierre
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p. 5087 - 5096
(2007/10/03)
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- The reaction of CF3OOCF2OF with fluoroolefins
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The reaction of fluoroxydifluoromethyl trifluoromethyl peroxide, CF3OOCF2OF (1), with fluoroolefins leads to the formation of novel fluorinated peroxides as major products.When 1 was added to 1,2-dichloro-1,2-difluoroethylene, CFCl=CFCl, under controlled conditions, the formation of 4,5-dichloro-2,2,4,5-tetrafluoro-1,3-dioxolane was also observed.A mechanism is proposed to rationalize these results. - Keywords: Fluoroolefins; Fluoroxydifluoromethyl trifluoromethyl peroxide; Synthesis; IR spectroscopy; NMR spectroscopy; Mass spectrometry
- Russo, A.,Montanari, V.,Navarrini, W.,DesMarteau, Darryl D.
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- Electronic Spectroscopy of CF3O in a Supersonic Jet: Symmetry and Rotational Structure of a Prototypical Perfluoroalkoxy Radical
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The electronic transition of CF3O was observed in a supersonic yet using laser-induced fluorescence.Rotational analysis of the high-resolution spectrum of the origin band is consistent with CF3O having C3ν symmetry in both its ground and excited electronic states.The lowest level is best described as 2E3/2 with residual unquenched electronic angular momentum, leading to a significant spin-orbit splitting.
- Tan, Xue-Qing,Yang, Min-Chieh,Carter, Christopher C.,Williamson, James M.,Miller, Terry A.,et al.
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p. 2732 - 2734
(2007/10/02)
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- Kinetics and Mechanism of the Thermal Reaction between Perfluorobutene-2 and Trifluoromethylhypofluorite
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The kinetics of the thermal reaction between CF3OF and C4F8 have been investigated in the range of 30 deg C to 90 deg C.It was found to be a homogeneous chain reaction of moderate length.The main product is CF3CF(OCF3)CF2CF3, accompanied by small amounts of C8F18, CF3OOCF3 and CF3CF(OCF3)CF(OCF3)CF3 in constant ratio.Traces of (CF3CF(OCF3)CFCF3)2 are also formed.Inert gases and reaction products have no influence on the reaction, whereas small amounts of oxygen change its course.Under conditions in which / > 1, the reaction follows a second order rate expressi on - = k.The following mechanism explains the experimental results .The chain length ν = /2 is found to be ν = 19+/-3 in the range 32 deg C to 92 deg C, the rate constant of the starting reaction k1 = (5.34+/-0.30)106exp(-13.9 kcal*mol-1/RT)l*mol-1*s-1. - Keywords: Kinetics / Thermal reaction / Perfluorobutene-2 / Trifluoromethylhypofluorite / Perfluoroalkyl radicals
- Santos Afonso, M. dos,Schumacher, H. J.
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- A NEW APPROACH TO THE MECHANISM OF THE FORMATION OF FLUOROOXYPERFLUOROALKANES AND RELATED COMPOUNDS
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Tetrafluoromethane and carbon dioxide are formed in the reaction of carbonyl difluoride with fluorine or fluorooxytrifluoromethane in the presence of carbon monooxide and cesium fluoride.This contradicts the SN2 reaction mechanism but indicates that trifluoromethoxyl radicals participate in the reactions.The generation of the trifluoromethoxyl radicals finds a satisfactory explanation in terms of single-electron transfer theory.
- Mukhametshin, F. M.,Povroznik, S. V.
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p. 853 - 856
(2007/10/02)
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- Stable fluorinated sulfuranes and sulfurane oxides. Synthesis and reactions
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Bis(trifluoromethyl) sulfide, tetrafluoro-1,3-dithietane, and bis(trifluoromethyl) sulfoxide undergo oxidative addition when photolyzed with trifluoromethyl hypochlorite to form a new family of sulfuranes, bis(trifluoromethyl)bis(trifluoromethoxy)sulfurane (1) and tetrafluoro-1,3-tetrakis(trifluoromethoxy)dithietane (3), and of sulfurane oxides, bis(trifluoromethyl)bis(trifluoromethoxy)sulfurane oxide (2). Compounds 1 and 2 are hydrolyzed to bis(trifluoromethyl) sulfoxide and bis(trifluoromethyl) sulfone, respectively. Pyrolysis of 1, 2, or 3 gives bis(trifluoromethyl) sulfide, bis(trifluoromethyl) sulfoxide, and tetrafluoro-1,3-dithietane, respectively, plus bis(trifluoromethyl) peroxide. With primary amines, 1 and 2 yield N-alkylbis(trifluoromethyl)sulfimides and sulfoxyimides, and with N,N′-diethylaminotrimethylsilane, imine formation occurs. Sulfurane oxide 2 forms a new type of stable sulfurane oxide (4), bis(trifluoromethyl)bis(hexafluoroisopropylidenimido)sulfurane oxide, with lithium hexafluoroisopropylidenimine. Sulfurane 1 acts in a similar manner with the nucleophile but the sulfurane 5 is not isolated. Compounds 1 and 2 form α,α,α-(trifluoromethyl)anisole derivatives with substituted phenols. Secondary and tertiary alcohols are dehydrated by 1 or 2 to olefins but symmetrical alkyl ethers result when primary alcohols are reacted.
- Kitazume, Tomoya,Shreeve, Jean'ne M.
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p. 2173 - 2176
(2007/10/10)
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