The radical reactions of polyolefin and olefin copolymers (4-9), polydienes and diene coplymers (10-15), and polysiloxane (16) with “magic blue” reagent containing H-abstracting agent-bis{perfluoro-1-[1-(2-fluorosulfonyl)ethoxy]ethyl}nitroxide [FSO2CF2CF2OCF(CF3)]2N(O) (2)and spin trap-perfluoro-1-nitroso-[1-(2-fluoro-sulfonyl)ethoxy]ethane FSO2CF2CF2OCF(CF3)NO (3) were studied by EPR detection of the spin adducts of the corresponding polymeric radicals generated in the H-abstraction step to the spin trap 3, namely, the nitroxides FSO2CF2CF2OCF(CF3)N(O) (polymer-H) 17-29. EPR studies have provided information about the regio-selectivity of H-abstraction, the subsequent radical steps followed H-abstraction and grounded a possibility of employing “magic blue” reagent in polymer modification via H-abstraction-initiated grafting polymerization. 相似文献
Hydrogen abstration from H2S by CF3 radicals, generated by the photolysis of both CF3COCF3 and CF3I, has been studied in the temperature range 314–434 K. The rate constant, based on the value of 1013.36 cm3/mol · s for the recombination of CF3 radicals, is given by with CF3COCF3 as the radical source, and with CF3I as the radical source, where k2 is in cm3/mol · s and E is in J/mol. These results resolve a previously existing controversy concerning the values of the rate constants for this reaction. They show that CF3 radicals are less reactive than CH3 radicals in attacking H2S, and this behavior indicates that polar effects play a significant role in the hydrogen transfer reactions of CF3 radicals. 相似文献
The following gas-phase reactions: were studied by the competitive method with CF3I as the source of radicals. The kinetic parameters obtained in the temperature range 533–613 K and 503–613 K respectively for chlorine atom transfer reactions are given by: where θ = 2.303 RT (cal mol?1). The Arrhenius A values were calculated for seven chlorine atom transfer reactions (CF2Cl2, CFCl3, CCl4 with CF3 radicals; CF3Cl, CF2Cl2, CFCl3 and CCl4 with CH3 radicals) by using the thermochemical kinetic version of the Transition State Theory (TST). 相似文献
Calculations were carried out using the semiempirical quantum chemical AMI method for anion radicals (AR) of the perfluoroalkyl halides (RFX): CF3X, CF3CF2X, (CF3)2-CFX, and (CF3)3CX for X=Cl, Br, and I. All the AR's studied are thermally stable. The electron affinity of the perfluoroalkyl halides, and consequently, the thermal stability of their AR's increases in the series from F-methyl to F-tertbutyl halides and from the chlorides to bromides and iodides. During formation of an AR the spin density is preferentially localized on the * orbital of the C–X bond which leads to an increase in the distance between these atoms. Dissociation of the AR of tert-perfluorobutyl iodide to a perfluorocarbanion and an I atom is thermodynamically more favorable than dissociation with formation of a perfluoroalkyl radical and I–.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1064–1068, May, 1990. 相似文献
Trifluoronitrosomethane reacts with bis(trifluoromethyl)phosphine to give (CF3)2P(O)N(OH)CF3 and a small amount of (CF3)2NOH. On the other hand, the reactions with tris(trifluoromethyl)phosphine and bis(trifluoromethyl)chlorophosphine afford (CF3)2NOP(O)CF3N(CF3)2 and (CF3)2NP(O)(CF3)Cl respectively. Isomerisation of may be involved as found for the isomerisation of the phosphine, (CF3)2NOP(CF3)2, to the phosphoryl compound, (CF3)2NP(O)(CF3)2. Mechanisms for the above reactions are discussed. 相似文献
A method for generating energetic beams of CF3I molecules and CF3 radicals was described. The method is based on the formation of pressure shock in front of a solid surface due to the impact of an intense, pulsed, gas-dynamically cooled molecular beam (or flow) on this surface and its use as a source of a secondary beam for producing energetic molecules. The secondary beam was formed upon efflux of molecules from the pressure shock through an orifice into a high-vacuum chamber compartment. The accelerated CF3I molecular beam was generated by exciting the molecules with a powerful IR laser pulse in the pressure shock (in the secondary-beam source itself) and the beam of energetic CF3 radicals was produced through the dissociation of CF3I in either the pressure shock or the accelerated beam. High-density (1020 molecule/(sr s)) beams of CF3I molecules and CF3 radicals with a kinetic energy of 1.2 and 0.4 eV, respectively, were obtained. 相似文献
The kinetics of photodecomposition of long-lived [(CF3)2CF]2C·C2F5 radicals (I) in glassy and liquid hexafluoropropylene trimer was studied at 77 and 300 K, respectively. It was found that the phase state of the hexafluoropropylene trimer matrix did not affect the photodecomposition mechanism. In both cases, I eliminates ·CF3 radical from the perfluoroethyl fragment. The molar absorption coefficient of I was determined: 250 = 49 m2 mol–1. It was shown that the photodecomposition of I in a liquid matrix at 300 K led to the formation of other long-lived radicals. One of these species is [(CF3)2CF]3C· radical, which results from addition of ·CF3 radical to the double bond of a hexafluoropropylene trimer molecule. 相似文献
CF3 radicals were generated by the photolysis of perfluoroacetic anhydride. In the presence of pentafluorobenzene, the CF3 radicals react according to the following mechanism: It was found that the addition reaction (3) becomes reversible above ca. 453 K. The addition rate parameters have been revised and they satisfactorily agree with those reported previously. At temperatures higher than 593 K, only true H-abstraction occurs. The rate constant kH for reaction (5) is given by: where θ = 2.303 RT kJmol?1 and kc is the rate constant for combination of CF3 radicals. The reactions of CF3 with benzene and pentafluorobenzene are compared. 相似文献
The first N-containing trifluorovinyl ether monomer (CF3)2NCF2OCFCF2 was synthesized. The starting perfluoroalkyl imine CF3–NCF2 was converted to the perfluoroalkyl amine (CF3)2NH by HF. The amine was converted into the carbamoyl fluoride (CF3)2NC(O)F via reaction with carbonyl fluoride COF2 in the presence of NaF. The carbamoyl fluoride was subjected to catalytic fluorination with molecular F2 in the presence of CsF to afford the hypofluorite (CF3)2NCF2(OF). The hypofluorite was added to CFClCFCl to provide a saturated halocarbon ether. Dechlorination of the ether with zinc in DMSO resulted in the title monomer. The new vinyl ether monomer readily copolymerizes with TFE. 相似文献
(CF3)2CN2 (1) and CF3CHN2 (4) react with (CF3)2CNSCl (2) to give (CF3)2CNSCCl(CF3)2 (3) and (CF3)2CNSCHClCF3 (5) respectively. From (4) and (NSCl)3 CF3CHNSCHClCF3 (6) and (8) are obtained. 相似文献
It has been found that a mixture of (CF3SO2)2CH2 and (CF3SO2)2CBr2 can be used instead of (CF3SO2)2CHBr in the radical addition to H2CCF2; the 1:1 and 1:2 adducts have been isolated and characterized. An improved synthesis of (CF3SO2)2CBr2 is also reported. 相似文献
The high temperature reaction of C60 with silver(I) trifluoroacetate followed by 500 °C sublimation and subsequent HPLC purification has led to the isolation of the five trifluoromethyl[60]fullerenes C60(CF3)n (n=2, 4, 6, 8, 10). Four of them have >90% compositional purity. Two of the compounds, C60(CF3)4 and C60(CF3)6, were obtained as C1-symmetry isomers with >90% isomeric purity, and a sample of C60(CF3)2 also contained ca. 15-20% of a Cs-symmetry isomer of C60(CF3)4. The new compounds were characterized by IR and EI mass spectrometry (all five compounds), NMR spectroscopy (C60(CF3)2, C60(CF3)4, and C60(CF3)6), and 2D COSY NMR spectroscopy (C60(CF3)4 and C60(CF3)6). Calculations at the AM1 and DFT levels of theory have led to the prediction of the most likely structures for C60(CF3)2, C1-C60(CF3)4, Cs-C60(CF3)4, and the two most likely structures of C1-C60(CF3)6. 相似文献
Reaction of quadricyclane (1) with fluoroolefins of different structure results in stereoselective formation of polyfluorinated exo-tricyclo[4.2.1.02,5]non-7-enes. The reaction of a mixture of trans/cis CF3CFCFCF3 with 1 is stereoselective and the resulting cycloadducts 7a, b preserve the original alkene stereochemistry. The relative rate constants of cycloaddition of a series of fluoroolefins to 1 under pseudo first-order conditions measured by kinetic NMR at 109 °C provide a kinetic scale of reactivities of the fluoroolefins in this reaction.These relative rate constants correlate well with the number of fluoroalkyl groups connected to the double bond, reaching a maximum for the tri-substituted olefin: CF3CFCF2:CF3CFCFCF3:(CF3)2CC(CF3)2:(CF3)2CCFC2F5 = 1:1.2-1.9:4:138. 相似文献
Dehydrofluorination of 1-aryl-1,2,2,2-tetrafluoroethanes (ArCHFCF3) and 1-aryl-1-chloro-2,2,2-trifluoroethane (ArCHClCF3) using lithiumhexamethyldisilazide (LHMDS) in tetrahydrofuran (THF) at room temperature produced 1,2,2-trifluorostyrene and 1-chloro-2,2-difluorostyrene, respectively, in very good isolated yields. Dehydrofluorination of 1,2,2,3,3,3-hexafluoro-1-phenyl-propane (PhCHFCF2CF3) and 1,2,2,3,3,4,4,4-octafluoro-1-phenyl-butane (PhCHFCF2CF2CF3) using LHMDS produced the corresponding substituted olefins (1-phenyl-1,2,3,3,3-pentafluoroprop-1-ene and 1-phenyl-1,2,3,3,4,4,4-pentafluorobut-1-ene) in good yield and high E-selectivity. Dehydrofluorination of 1-chloro-1-phenyl-2,2,3,3,3-pentafluoropropane (PhCHClCF2CF3) and 1-chloro-1-phenyl-2,2,3,3,4,4,4-heptafluorobutane (PhCHClCF2CF2CF3) produced a mixture of the corresponding E and Z olefins (PhCClCFCF3 and PhCClCFCF2CF3) in good yield. 相似文献
Fluorinated polyacrylats with side group containing vinylidene fluoride (VDF) units (CF3(CF2)n (CH2CF2)m, n = 3, 5; m = 1, 2) were successfully synthesized. The water and oil repellency properties of these polymers are similar to those of fluorinated polyacrylate with side group containing long perfluorooctyl group (CF3(CF2)7). The thermal telomerization of CF3(CF2)5I and CF3(CF2)3I with vinylidene fluoride (VDF) provided CF3(CF2)5CH2CF2I (1b) and CF3(CF2)3CH2CF2CH2CF2I (1c), respectively. The addition of 1b with ethylene followed by hydrolysis gave CF3(CF2)5CH2CF2CH2CH2OH (2b). Treatment of 1c with ethyl vinyl ether in the presence of Na2S2O4 followed by reduction produced CF3(CF2)3CH2CF2CH2CF2CH2CH2OH (2c). Fluoroacrylates 3b-d were prepared by acrylation of the corresponding fluoroalcohols 2b-d. The semi-continuous process emulsion co-polymerization of 3a-d with octadecyl acrylate and 2-hydroxylethyl acrylate initiated by (NH4)2S2O8 in the presence of a mixture emulsifiers of polyoxyethylene(10)nonyl phenyl ether (TX-10) and sodium lauryl sulfate provided stable latexes 4a-d, respectively. The water and oil repellency properties of 4b (Rf: CF3(CF2)5CH2CF2) and 4c (Rf: CF3(CF2)3CH2CF2CH2CF2) containing vinylidene fluoride (VDF) units were similar to those of 4a (Rf: CF3(CF2)7) containing long perfluoroalkyl group and much better than those of polymer 4d (Rf: CF3(CF2)3) with short perfluoroalkyl chain. Thus, polyacrylates containing vinylidene fluoride units showed promising aspects as the alternatives to the currently used water and oil repellent agents with long perfluoroalkyl chains. 相似文献
(CF3)2PAsH2 and (CF3)2AsAsH2 (CF3)2PAsH2 is obtained in yields between 30 and 60% according to eq. (1) (CF3)2AsAsH2 is formed by the analogous reaction with (CF3)2AsI, but is not sufficiently stable to be isolated. Both compounds are decomposed according to eq. (2) (CF3)2PAsH2 can be studied in solution below ?40°C; it is characterized by molar mass determination and by its n.m.r. spectra (1H, 19F, 31P). Reactions with polar [HBr, (CH3)2AsH, (CH3)2PN(CH3)2] and nonpolar [Br2, As2(CH3)4] reagents proceed by cleavage of the P? As bond. 相似文献