The reaction of CF3 radicals, generated by photolysis of CF3I or hexafluoroacetone with thiophene, was studied in the gas phase at 25degreesC. At conversion of thiophene less than 20%, monosubstituted CF3-thiophenes were found as the main reaction products, in addition to CF3H, C2F6, and monosubstituted dihydro-CF3-thiophene, the latter in very low proportion. An isomeric mixture of 2- and 3-CF3-thiophene was obtained in a ratio of about 16, independent of the radical source used (CF3I or hexafluoroacetone) to produce the CF3 radicals. A plausible mechanism that accounts for the observed products is proposed, and the reactivity of thiophene toward the CF3 radical at 25degreesC was determined as k(add)/k(c)(1/2) = 106 +/- 4 cm(3/2) mol(-1/2) s(-1/2).

The temperature dependence of the rate constant for the gas phase abstraction reaction of chlorine by CF3 from chloropentafluorobenzene was determined in the temperature range 573-653 K by the competitive method using the recombination of CF3 radicals as reference reaction. Taking a value of 1.5310(13) cm(3) mol(-1) s(-1) for the recombination rate constant, k(cl)=(6.76+/-1.26) 10(12) exp [-(6339+/-103) K/T] cm(3) mol(-1) s(-1). The Arrhenius parameters were calculated by the Bond Strength-Bond Length method (BSBL) and good agreement was obtained with the experimental values.

The gas-phase reaction of CF 3 radicals, generated by photolysis of perfluoroacetic anhydride, with C 6 F 5 Cl was studied in the temperature range 318-473 K and total pressures between 23 and 41 Torr. CF 3 radicals react with C 6 F 5 Cl according to the following mechanism: CF 3 +C 6 F 5 Cl ⇄ k add CF 3 C 6 F 5 Cl CF 3 +CF 3 C 6 F 5 CI → CF 3 Cl+C 6 F 5 CF 3 2CF 3 → k c C 2 F 6 It was found that the addition reaction becomes reversible above 390 K. The addition rate parameters can be summarized in the following equation: log [(k add /k c 1/2 ) mol -1/2 cm 3/2 s -1/2 ] = (4.46±0,10)-(22.48 ± 0.70)/θ where θ = 2.303 R TkJ mol -1 and k c is the recombination constant of CF 3 radicals. A correlation between log (k add /k c 1/2 ) and the ionization potentials for 15 aromatic compounds was found.

El presente proyecto, en parte continuacion de un proyecto anterior, tratara el estudio de reacciones de los compuestos no saturados con el radical CF3 y C2F5, en fase gaseosa como tambien en solucion ya que solo existe, en algunos casos, informacion de los productos fluorados. Recientemente se aportaron resultados referentes a reacciones del radical C2F5 con metilestireno en solucion a partir de la deteccion del intermediario formado en la reaccion (tecnica de absorcion resuelta en el tiempo) lo que permitio la determinacion de las constantes de velocidades absolutas de adicion. Objetivos generales y especificos: El objetivo general del presente proyecto consiste en el estudio sistematico de un conjunto de reacciones, a los fines de determinar los mecanismos de reaccion que conducen a la formacion de los productos, establecer los parametros cineticos, realizar la comparacion de los mismos con los obtenidos de calculos teoricos que permiten predecir las constantes de velocidad y ademas correlaciones con algunas propiedades moleculares determinadas experimentalmente como los potenciales de ionizacion, las energias de disociacion de enlace, las afinidades electronicas, etc. a los efectos de analizar los factores que gobiernan las reactividades de reacciones de radicales con compuestos organicos de interes en la quimica atmosferica y con fines de sintesis de nuevos compuestos. Especificamente se estudiaran las reacciones en fase gaseosa del radical CF3, generado por la descomposicion multifotonica infrarroja, con cianuro de hidrogeno, como asi tambien con tiofeno y pirrol a partir de la fotolisis estacionaria del CF3I. Se implementara el montaje de la tecnica para la determinacion de intermediarios en la reaccion del radical C2F5 con cloropentafluorbenceno en solucion a partir de la fotolisis pulsada por laser del perfluoretilperoxido como precursor.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

International Journal of Chemical KineticsVolume 25, Issue 1 p. 63-66 Communication The reactions of c-C3H5 radicals with HCN and ClC6H5 in CCl4 Jorge D. Nieto, Jorge D. Nieto Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, ArgentinaSearch for more papers by this authorOlga S. Herrera, Olga S. Herrera Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, Argentina Dpto. de Química, Fac. de Ciencias Naturales, U.N. de La Patagonia S.J.B., C.C. 786, 9000 Comodoro Rivadavia, Argentina.Search for more papers by this authorSilvia I. Lane, Silvia I. Lane Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, ArgentinaSearch for more papers by this authorElena V. Oexler, Elena V. Oexler Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, ArgentinaSearch for more papers by this author Jorge D. Nieto, Jorge D. Nieto Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, ArgentinaSearch for more papers by this authorOlga S. Herrera, Olga S. Herrera Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, Argentina Dpto. de Química, Fac. de Ciencias Naturales, U.N. de La Patagonia S.J.B., C.C. 786, 9000 Comodoro Rivadavia, Argentina.Search for more papers by this authorSilvia I. Lane, Silvia I. Lane Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, ArgentinaSearch for more papers by this authorElena V. Oexler, Elena V. Oexler Instituto de Investigaciones en Fisicoquímica de Córdoba (INFIQC), Dpto. de F. Química, Fac. de Ciencias Químicas, U.N.C. Suc. 16, C.C. 61, 5016 Córdoba, ArgentinaSearch for more papers by this author First published: January 1993 https://doi.org/10.1002/kin.550250107Citations: 2 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume25, Issue1January 1993Pages 63-66 RelatedInformation

CF3 radicals were generated by the photolysis of perfluoroacetic anhydride. In the presence of pentafluorobenzene, the CF3 radicals react according to the following mechanism:[GRAPHICS]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 k(H) for reaction (5) is given by: log[(k(H)/k(c)1/2) mol-1/2 cm3/2 s-1/2] = (4.34 +/- 0.43) - (59.00 +/- 2.62)/theta where theta = 2.303 RT kJmol-1 and k(c) is the rate constant for combination of CF3 radicals. The reactions of CF3 with benzene and pentafluorobenzene are compared.

The IR multiphoton dissociation of CF3I has been studied in the presence of isobutane and with isobutane and Ar and CO2 as inert gases. The dependence of the reaction probability P(Φ) with fluence (ϕ) is confirmed. Modeling of the experimental results shows that for the energy transfer processes the average energy transferred per collision 〈†E〉d varies with (ϕ).

The photolysis of C2F5I with CF3COOH in the temperature range 473-533 K was studied in the gas phase.Evidence is presented that supports a complex mechanism for the formation of C2F5H through the H-atom abstraction reaction from CF3COOH by C2F5 radicals as well as the participation of I(2P1/2).

The reaction of CF3 radicals produced by photolysis of CF3I with HCN has been investigated in the temperature range 333–523 K. The radicals react with HCN by addition followed by a sequence of reactions of which the most important are: CF3+ HCN ⇆ CF3HCN (1,–1), CF3+ CF3HCN → HCF3CNCF3(2), CF3+ CF3HCN → CF3H + CF3CN(3), I + CF3HCN → HI + CF3CN (4) 2 CF3 [graphic omitted] C2F6. Arrhenius parameters for the addition reaction relative to radical recombination were estimated from experiments at conversions [graphic omitted] 3% in the temperature range 333–453 K. The best fit to our experimental results gave log[(A1/A1/2c) cm3/2 mol–1/2 s–1/2]= 4.97 and E1–½Ec= 30.9 kJ mol–1, with systematic estimated errors of up to 0.3 and 2.4 kJ mol–1, respectively. These parameters are compared with those obtained for other addition reactions of these radicals to substrates with a triple bond.

Chemischer InformationsdienstVolume 16, Issue 8 Preparative Organic Chemistry ChemInform Abstract: CONVERSION EFFECT ON THE REACTION TRIFLUOROMETHYL HYDROCYANIC ACID. ANALYSIS OF MOLECULAR AND ATOMIC IODINE PARTICIPATION WITH TRIFLUOROIODOMETHANE AS RADICAL SOURCE S. I. LANE, S. I. LANESearch for more papers by this authorE. V. OEXLER, E. V. OEXLERSearch for more papers by this authorE. H. STARICCO, E. H. STARICCOSearch for more papers by this author S. I. LANE, S. I. LANESearch for more papers by this authorE. V. OEXLER, E. V. OEXLERSearch for more papers by this authorE. H. STARICCO, E. H. STARICCOSearch for more papers by this author First published: February 26, 1985 https://doi.org/10.1002/chin.198508130AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume16, Issue8February 26, 1985 RelatedInformation

The reaction of CF3 radicals with CH3CN has been studied over the temperature range 298–623 K, using the photolysis of perfluoroacetic anhydride as a radical source. At temperatures higher than 473 K, the photolysis and the thermal decomposition of CF3I have also been used to generate CF3. — Arrhenius parameters for the reaction were measured relative to the CF3 recombination. The average value of the results from both sources of radicals gave the following parameters The high primary kinetic isotope effect and the non-curved Arrhenius plot found confirm the absence of an addition reaction.

AbstractThe gas‐phase reaction of CF3 with HCN has been examined over a wide conversion range using CF3I as a thermal and photolytic source of radicals. Quantitative and qualitative results show a significant increase of the specific rate constant for the hydrogen abstraction reaction relative to CF3 recombination when reaction is carried out under ultraviolet irradiation. This “extra” formation of the reaction product, CF3H, has been assigned to the participation of iodine in this system through the formation of a (I‐HCN) intermediate. Arrhenius parameters obtained for the addition mechanism of I to HCN do not seem to conform to a single reaction step, on the contrary, they correspond to a more complex reaction scheme.

The reaction of CF 3 radicals with H 2 O (D 2 O) has been studied over the range of 533–723 K using the photolysis and the pyrolysis of CF 3 I as the free radical source. Arrhenius parameters for the reactions where X = H or D, relative to CF 3 radical recombination are given by where k / k is in cm 3/2 /mol 1/2 ·s 1/2 and θ = 2.303 RT /cal/mol. The activation energy and the primary kinetic isotope effect have been compared with those derived from the BEBO method.

The reaction of CF3 radicals with HCN in the gas phase has been studied in the temperature range 573–673 K using CF3 radicals generated by thermal decomposition of CF3I. Arrhenius parameters for the reaction: relative to CF3 recombination: are given by: Rate parameters are compared with those for other reactions of CF3 with polar and non-polar substrates.

AbstractThe reaction of C2F5 radicals with HCN has been studied over the range of 533–673 K using the pyrolysis of pentafluoroethyl iodide as the free‐radical source. Arrhenius parameters for the reaction equation image relative to C4F10 recombination are given by where θ = 2.303RT kJ/mol and kH/k is in cm3/2/mol1/2·s1/2.

Chemischer InformationsdienstVolume 14, Issue 48 Preparative Organic Chemistry ChemInform Abstract: REACTION OF TRIFLUOROMETHYL RADICALS WITH WATER AND WATER-D2 L. PASTERIS, L. PASTERISSearch for more papers by this authorE. V. OEXLER, E. V. OEXLERSearch for more papers by this authorE. H. STARICCO, E. H. STARICCOSearch for more papers by this author L. PASTERIS, L. PASTERISSearch for more papers by this authorE. V. OEXLER, E. V. OEXLERSearch for more papers by this authorE. H. STARICCO, E. H. STARICCOSearch for more papers by this author First published: November 29, 1983 https://doi.org/10.1002/chin.198348115AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References L. PASTERIS, E. V. OEXLER, E. H. STARICCO, REACTION OF TRIFLUOROMETHYL RADICALS WITH WATER AND WATER-D2, Int. J. Chem. Kinet., 1983, 15, 835. DOI: 10.1002/kin.550150812; 10.1002/kin.550150812 CASWeb of Science®Google Scholar Volume14, Issue48November 29, 1983 ReferencesRelatedInformation

The reaction of CF3 radicals with ClCN has been studied over a wide temperature range, 268–293 K, using CF3 radicals generated by the photolysis of CF3I. Over the range 408–473 K, CF3COCF3 was also used as a CF3 radical source. The radicals react with ClCN by addition followed by decomposition of the adduct and by chlorine abstraction: CF3+ ClCN ⇌ CF3ClCN (1), (– 1), CF3ClCN → CF3Cl + CN (2), CF3+ ClCN → CF3Cl + CN (3), 2 CF3 [graphic omitted] C2F6. The Arrhenius plot for this reaction is strongly curved. Using data from the low- and high-temperature regions, the following expressions for the rate constants for addition reaction (1) and chlorine abstraction (3) relative to CF3 recombination have been obtained: log[(k1/k½c)/cm mol–½s½]= 3.75 – 26.55 kJ mol–1/2.303 RT, log[(k3/k½c)/cm mol–½s½]= 6.43 – 48.61 kJ mol–1/2.303 RT. The combination of E1 with the difference E–1–E2, which can be estimated, gives an upper limit for ΔH°3 from which an approximate value for ΔH°f(CN) of 393.4 kJ mol–1 or less has been obtained.