- LASER-DRIVEN OXIDATION OF SOME HALOOLEFINS
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CW CO2 laser-photosensitized (SF6) oxidation of hexafluoropropene, chlorotrifluoroethene, 1,1-dichlorodifluoroethene, 1,2-dichlorodifluoroethene and hexafluoro-1,3-butadiene with molecular oxygen at total pressure 13-26.5 kPa leads with all but the last to the formation of carbonyl halides.The distribution of these products suggests that the oxidation occurs via a cleavage of intermediary dioxetanes.The reactivities of the olefins towards oxygen at mean effective temperature 710 K are nearly equal.
- Pola, J.,Chvatal, Z.
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- Atmospheric Cryochemistry: Oxygen Atom Reaction with Fluorocarbon Freon 11 in Matrices. FTIR Spectra of Isolated COFCl and COFCl:Cl2 Complex in Solid Argon
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Fourier transform infrared spectroscopy has been employed to investigate the reaction of CFCl3 (Freon 11) with atomic oxygen in argon and oxygen matrices at 12 K.Ozone was employed as a photolytic oxygen atom source.The results indicate that the only primary reaction product is COFCl when the oxygen atom is in an excited state.No intermediate was observed.Upon thermal annealing after photolysis, diffusion through the matrix leads to the efficient formation of COFCl:Cl2 aggregates.The spectra obtained after irradiation in various experimental series (isotopic ozone, wavelength dependence, product growth curves) are analyzed and have been interpreted from vibrational spectra of normal and isotopically substituted COFCl isolated in argon and from vibrational spectra of their molecular complexes with Cl2 embedded in argon.Fermi resonance doublets in the νC=O stretching region are observed mainly for the C18OFCl species and the C16OFCl...Cl2 complex
- Schriver, L.,Abdelaoui, O.,Schriver, A.
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- Time-Resolved Observation of the Formation of CF2O and CFClO in the CF2Cl + O2 and CFCl2 + O2 Reactions. The Unimolecular Elimination of Cl Atoms from CF2ClO and CFCl2O Radicals
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The unimolecular elimination of chlorine atoms from CF2ClO and CFCl2O radicals has been observed at 238 and 298 K and at 4-20 Torr total pressure by measurement of the rate of formation of the carbonyl halide product in real time.The fragment ion (CFO)+ w
- Wu, Fuxiang,Carr, Robert W.
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- Production of carbonyl fluoride
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Carbonyl fluoride, which can also be used as an etching gas, can be prepared by photochemical oxidation of chlorodifluoromethane or trifluoromethane with light, for example with light of a wavelength >=280 nm in the presence of chlorine.
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Page/Page column 3; 4
(2008/06/13)
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- Continuous production of chlorodifluoroacetyl fluoride via chlorotrifluoroethylene oxidation
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The invention pertains to a process for preparing chlorodifluoroacetyl fluoride (CDAF) by oxidation of chlorotrifluoroethylene (CTFE) in a solvent using a continuously stirred tank reactor. It provides a process for the production of chlorodifluoroacetyl fluoride by comprises reacting a solvent solution of chlorotrifluoroethylene with oxygen in a reactor to form a product which comprises chlorodifluoroacetyl fluoride. The reacting may be conducted in a continuous or batch mode.
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Page/Page column 2-3
(2008/06/13)
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- Kinetics and Mechanism of the Thermal Reaction between Trifluoromethylhypofluorite and 1,1-Dichlorodifluoroethylene
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The thermal addition of CF3OF to CF2CCl2 has been studied between -7.0 and 29.7 deg C.The pressure of CF3OF was varied between 6.4 and 196.7 Torr and that of CF2CCl2 between 5.4 and 203 Torr.CF3CCl2F, CF3O(CF2CCl2)F and CF3O(CF2CCl2)iOCF3, where i = 2,3. . .n, were the products.Above 110 Torr of olefin, non-volatile condensate appeared.The reaction was homogeneous and not affected by the total pressure or the presence of an inert gas.Introducing a few Torr of O2 to the reaction system an instantaneous oxidation of CF2CCl2 to CF2ClC(O)Cl occurred.Higher amounts of O2 led to explosion with conversion of both reactant molecules.The basic steps of the reaction were: generation of radicals CF3O. and CF3CCl2. in the bimolecular process between CF3OF and CF2CCl2 (rate constant k1), generation of telomeric radicals by addition of CF3O. to CF2CCl2, abstraction of fluorine atoms from CF3OF by CF3CCl2. and by CF3O(CF2CCl2). (rate constant k4), chain propagation by further successive addition of telomeric radicals to another molecule of olefin (k5) and recombination of telomeric radicals.The following values of the rate constants were obtained: k1 = (5.0+/-1.0)106exp(-9.7+/-0.9 kcal*mol-1/RT)l*mol-1s-1, k4 = (2.6+/-0.5)107exp(-3.1+/-0.6 kcal*mol-1/RT)l*mol-1s-1, k5 = (1.7+/-0.4)105exp(-2.5+/-0.5 kcal*mol-1/RT)l*mol-1s-1. - Keywords: CF3OF, thermal reaction with CCl2CF2 / CCl2CF2, thermal reaction with CF3OF / Trifluoromethylhypofluorite, addition to 1,1-dichlorodifluoroethylene / 1,1-Dichlorodifluoroethylene, reaction with trifluoromethylhypofluorite
- Santos Afonso, M. dos,Czarnowski, J.
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- Characterisierung und Photochemie von (Dihalogenmethylen)sulfoxiden, XYC=S=O
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Dihalogenomethylene sulfoxides (dihalogenosulfines) 2a-c were generated by flash vacuum pyrolysis of 2,2,4,4-tetrahalogeno-1,3-dithietane 1,3-dioxides 1a-c and trapping the pyrolysis products in argon at 10 K.At room temperature unstable difluorosulfine (2a) and chlorofluorosulfine (2b) were identified by i.r.spectroscopy, and the photochemistry of the sulfines was investigated.Chlorofluorosulfine (2b) exists in two geometrical isomers.Photolysis of 2a leads to fragmentation to give CF2 and SO, photolysis of the chlorine containing sulfines 2b and 2c to rearrangement to give sulfenyl chlorides 6 and 8.This is explained by different migratory tendencies of fluorine and chlorine and the stability of C-F bond.
- Sander, Wolfram,Henn, Rolf,Sundermeyer, Wolfgang
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p. 1281 - 1288
(2007/10/02)
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- THE PREPARATION OF FLUOROARENES BY THE CATALYTIC DECARBOXYLATION OF ARYL FLUOROFORMATES
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The catalytic decarboxylation of phenyl fluoroformate to fluorobenzene has been achieved with yields of 70-80percent in a flow system using alumina or alumina-based catalysts.The reaction occurs in short space times (Pd/Al2O3>Rh/Al2O3 ca.Al2O3. 2,4,6-Trimethylphenyl fluoroformate, a new material, was found to decarboxylate similarly to give 1-fluoro-2,4,6-trimethylbenzene, but 4-chlorophenyl fluoroformate was noted to produce only low yields (ca. 10percent) of the corresponding aryl fluoride.
- Ashton, David P.,Ryan, Anthony T.,Webster, Brian R.,Wolfindale, Brett A.
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p. 263 - 274
(2007/10/02)
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- ACYLATIONS OF PENTAFLUOROSULFANYLAMINE, SF5NH2. PART II. REACTIONS OF N-PENTAFLUOROSULFANYLCARBAMYLFLUORIDE, SF5NHC(O)F, AND N-PENTAFLUOROSULFANYLPERFLUOROSUCCINIMIDE,
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The carbamyl fluoride SF5NHC(O)F reacts with both H2O and H2S to give the urea (SF5NH)2CO.Evidence supports that this reaction proceeds through a mechanism involving dehydrofluorination; whereas, the reagents PhLi and PCl5 serve only to dehydrofluorinate SF5NHC(O)F.The ring of the cyclic imide can be readily opened by nucleophiles to give products such as SF5NHC(O)CF2CF2C(O)OH, SF5NHC(O)CF2CF2C(O)NH2, and SF5NHC(O)CF2CF2C(O)OCH3.Attempts to prepare analogous six- and seven-membered cyclic imides failed; however, mono- (SF5NHC(O)(CF2)3,4C(O)F) and disubstituted products (SF5NHC(O)(CF2)3,4C(O)NHSF5) were formed.The amide-acid fluorides are easily hydrolyzed by atmospheric moisture to the amide-acids SF5NHC(O)(CF2)3,4C(O)OH.
- Thrasher, Joseph S.,Howell, Jon L.,Clifford, Alan F.
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p. 431 - 442
(2007/10/02)
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- Emission from FCO in the Reactions of Ozone with Fluoroethenes
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The gas-phase reactions of ozone with cis-1,2-difluoroethene, trans-1,2-difluoroethene, trifluoroethene, and chlorotrifluoroethene are all accompanied by light with a maximum intensity at approximately 425 nm.A partial vibrational analysis of this emission is presented and it is concluded that the emitting species is the FCO radical, as previously suggested.A comparison is made between the enthalpy changes of the primary reactions between ozone and the fluoroethenes and their correlation with the identity of the emitting species.The exothermicity of the reaction correlates with the chemiluminescent reaction channel.
- Toby, Sidney,Toby, Frina S.
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p. 4071 - 4073
(2007/10/02)
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- Some chemistry of difluoraminocarbonyl chloride. A new route to perfluorourea
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Improved yields of NF2C(O)Cl are obtained by short-term (4-6 hr) photolysis of N2F4 with oxalyl chloride. Reactions of NF2C(O)Cl with AgCN, AgNCS, AgNCO, Hg(SCF3)2 and Hg(ON(CF3)2)2 give the new difluoraminocarbonyl pseudohalides NF2C(O)CN, NF2C(O)NCS, NF2C(O)NCO, NF2C(O)SCF3, and NF2C(O)ON(CF3)2. With excess of either Ag2O at 0° or HgO at -78°, NF2C(O)Cl is converted to (NF2)2CO and CO2 in nearly quantitative yield. Chlorocarbonyl fluorosulfate results when NF2C(O)Cl is mixed with S2O6F2 or BrOSO2F.
- Wright, Kenneth J.,Shreeve, Jean'ne M.
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- Some chemistry of difluoraminocarbonyl fluoride, NF2CFO. The preparation of perfluorourea, (NF2)2CO, and difluoraminocarbonyl chloride, NF2C(O)Cl. New preparations for NF2OCF3 and NF2<
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Reactions of NF2CFO with CF3OF or with Al2Cl6 and HCl yield NF2OCF3 or NF2C(O)Cl, respectively. The reactions of NF2CFO with KF and CsF to give KOCF2NF
- Fraser, George W.,Shreeve, Jean'ne M.
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p. 1711 - 1715
(2008/10/08)
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