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1. Relative-rate study of thermal decomposition of the 2-butoxyl radical in the temperature range 280–313 K

Author

Libuda, H. G., Shestakov, O., Theloke, J., and Zabel, F.

Abstract

The competition between thermal decomposition (kdis) and reaction with O2 (kO2) has been studied for the 2-butoxyl radical in a newly built 210 L photoreactor constructed of quartz. 2-Butoxyl radicals were generated by continuous 254 nm photolysis of 2-butoxyl iodide in the presence of O2 and NO, using N2 as a buffer gas. Reaction educts and products were analysed by long-path (29 m) IR absorption using an FTIR spectrometer. The ratio kdis/kO2 was derived from the product ratios of acetaldehyde and butanone, corrected for small amounts of side products. At 280, 298, and 313 K and a total pressure of 1 bar (M = O2 + N2), kdis/kO2 was determined at O2 partial pressures between 100 and 1000 mbar. At all temperatures, there was a systematic increase of (kdis/kO2)eff ≡ (Δ[CH3CHO]corr × [O2]) / (2 × Δ[CH3C(O)CH2CH3]) with the partial pressure of O2 which possibly is the result of an additional O2 independent source of acetaldehyde (≈8% of the 2-butoxyl radicals reacting by either of the two competing pathways at 298 K, 1 bar). Pressure-dependence studies between 100 and 1000 mbar support the hypothesis that the additional acetaldehyde originates from the formation of 6–10% chemically activated 2-butoxyl radicals in the temperature range 280–313 K. Correction of (kdis/kO2)eff for the O2 independent yield of acetaldehyde results in kdis/kO2 = (6.8 ± 1.4) × 1017, (2.3 ± 0.5) × 1018, and (5.5 ± 1.1) × 1018 molecule cm−3 at 279.8, 298.2, and 313.5 K, respectively, leading to the Arrhenius expression kdis/kO2 = (2.0 ± 0.5) × 1026exp(−45.4 kJ mol−1/RT) molecule cm−3 at a total pressure of 1 bar. This temperature dependence of kdis/kO2 implies that, depending on temperature, either thermal decomposition or reaction with O2 is the major loss process of 2-butoxyl radicals under the conditions of the lower troposphere. Using literature values for kO2, kdis = 3.9 × 1012 exp(−47.1 kJ mol−1/RT) s−1 is derived for a total pressure of 1 bar (M = N2 + O2), which compares very favourably with a recent theoretical estimate (ab initio + RRKM) by Somnitz and Zellner (H. Somnitz and R. Zellner, Phys. Chem. Chem. Phys., 2000, 2, 1907).

Published
2002
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2. Thermal stability of carbonyl radicals. Part I. Straight-chain and branched C<SUB>4</SUB> and C<SUB>5</SUB> acyl radicals

Author

Jagiella, S., Libuda, H. G., and Zabel, F.

Abstract

The competition between thermal decomposition (kdis) and O2 addition (kO2) of linear and branched C4 and C5 alkanoyl (R-C(•)O, R=alkyl) radicals has been studied in a photochemical reaction chamber made from stainless steel (v=12 L). RCO radicals were prepared by continuous photolysis of Br2–RC(O)H–O2–NO2–N2 mixtures at wavelengths 420 nm. The products CO and RC(O)O2NO2 were analyzed by long-path IR absorption using an FT-IR spectrometer. Rate constant ratios kdis/kO2 were determined at 317 K for n-butyryl, n-pentanoyl, 3-methylbutyryl, 2-methylpropionyl and 2-methylbutyryl and at 6 temperatures between 293 and 317 K for 2,2-dimethylpropionyl (=pivaloyl, t-butyl-CO) radicals. Total pressures were 1 bar (M=N2+O2). Adopting the literature value of kO2 for acetyl, unimolecular decomposition rate constants kdis were derived from the measured ratios kdis/kO2. kdis at 298 K, 1 bar, M=O2+N2 increases by factors of 35, 54 and 24 for each H atom in CH3CO which is consecutively replaced by a methyl group (corresponding to increasing branching of R). For the unimolecular decomposition of 2,2-dimethylpropionyl radicals, the Arrhenius expression kdis(t-butyl-CO)=6.0×1012 exp(-41.6 kJ mol-1/RT) s-1 (2σ) was derived for the temperature range 293–317 K and a total pressure of 1 bar (M=N2+O2). The results on kdis/kO2 show that even for the thermally most unstable of the carbonyl radicals studied in this work, i.e. 2,2-dimethylpropionyl, only 1.8% decompose rather than add O2 at 298 K and 1 bar in dry air.

Published
2000

3. Abstracts of the 6th FECS Conference 1998 Lectures

Author

Rowland, F. Sherwood, Blake, Donald R., Larsen, B. R., Lindskog, Anne, Peterson, Peter J., Williams, W. Peter, Wallington, T. J., Pilling, M. J., Carslaw, N., Creasey, D. J., Heard, D. E., Jacobs, P., Lee, J., Lewis, A. C., McQuaid, J. B., Stockwell, William R., Frank, Hartmut, Sacco, P., Cocheo, V., Lynge, E., Andersen, A., Nilsson, R., Barlow, L., Pukkala, E., Nordlinder, R., Boffetta, P., Grandjean, P., Heikkil, P., Hürte, L. G., Jakobsson, R., Lundberg, I., Moen, B., Partanen, T., Riise, T., Borowiak, A., De Saeger, E., Schnitzler, K. G., Gravenhorst, G., Jacobi, H. W., Moelders, S., Lammel, G., Busch, G., Beese, F. O., Dentener, F. J., Feichter, J., Fraedrich, K., Roelofs, G. J., Friedrich, R., Reis, S., Voehringer, F., Simpson, D., Moussiopoulos, N., Sahm, P., Tourlou, P. M., Salmons, R., Papameletiou, D., Maqueda, J. M., Suhr, Per B., Bell, W., Paton-Walsh, C., Woods, P. T., Partridge, R. H., Slemr, J., Slemr, F., Schmidbauer, N., Ravishankara, A. R., Jenkin, Michael E., de Leeuw, G., van Eijk, A. M. J., Flossmann, A. I., Wobrock, W., Mestayer, P. G., Tranchant, B., Ljungström, E., Karlsson, R., Larsen, S. E., Roemer, M., Builtjes, P. J. H., Koffi, Brigitte, Koffi, Ernest N’Dri, De Saeger, Emile, Ro-Poulsen, H., Mikkelsen, T. N., Hummelshøj, P., Hovmand, M. F., Simoneit, Bernd R. T., van der Meulen, A., Meyer, Michael B., Berndt, T., Böge, O., Stratmann, F., Cass, Glen R., Harrison, Roy M., Shi, Ji Ping, Hoffmann, T., Warscheid, B., Bandur, R., Marggraf, U., Nigge, W., Kamens, Richard, Jang, Myoseon, Strommen, Mike, Chien, Chao-Jung, Leach, Keri, Ammann, M., Kalberer, M., Arens, F., Lavanchy, V., Gâggeler, H. W., Baltensperger, U., Davies, J. A., Cox, R. A., Alonso, S. García, Pastor, R. Pérez, Argüello, Gustavo A., Willner, Helge, Berndt, T., Böge, O., Bogillo, V. I., Pokrovskiy, V. A., Kuraev, O. V., Gozhyk, P. F., Bolzacchini, E., Bruschi, M., Fantucci, P., Meinardi, S., Orlandi, M., Rindone, B., Bolzacchini, Ezio, Bohn, Birger, Rindone, Bruno, Bruschi, Maurizo, Zetzsch, Cornelius, Brussol, C., Duane, M., Larsen, B., Carlier, P., Kotzias, D., Caracena, A. Baeza, Aznar, A. Miñana, Ferradás, E. González, Christensen, C. S., Skov, H., Hummelshøj, P., Jensen, N. O., Lohse, C., Cocheo, V., Sacco, P., Chatzis, C., Cocheo, V., Sacco, P., Boaretto, C., Quaglio, F., Zaratin, L., Pagani, D., Cocheo, L., Cocheo, Vincenzo, Asnar, Agustin Minana, Baldan, Annerita, Ballesta, Pascual P., Boaretto, Caterina, Caracena, Antonia B., Ferradas, Enrique Gonzalez, Gonzalez-Flesca, Nobert, Goelen, Eddie, Hansen, Asger B., Sacco, Paolo, De Saeger, Emile, Skov, Henrik, Consonni, V., Gramatica, P., Santagostino, A., Galvani, P., Bolzacchini, E., Consonni, Viviana, Gramatica, Paola, Todeschini, Roberto, Dippel, G., Reinhardt, H., Zellner, R., Dämmer, K., Bednarek, G., Breil, M., Zellner, R., Febo, A., Allegrini, I., Giliberti, C., Perrino, C., Fogg, P. G. T., Geiger, H., Barnes, I., Becker, K. H., Maurer, T., Geyskens, F., Bormans, R., Lambrechts, M., Goelen, E., Giese, Martina, Frank, Hartmut, Glasius, M., Hornung, P., Jacobsen, J. K., Klausen, H. S., Klitgaard, K. C., Møller, C. K., Petersen, A. P. F., Petersen, L. S., Wessel, S., Hansen, T. S., Lohse, C., Boaretto, E., Heinemeier, J., Glasius, M., Di Bella, D., Lahaniati, M., Calogirou, A., Jensen, N. R., Hjorth, J., Kotzias, D., Larsen, B. R., Gonzalez-Flesca, N., Cicolella, A., Bates, M., Bastin, E., Gurbanov, M. A., Akhmedly, K. M., Balayev, V. S., Haselmann, K. F., Ketola, R., Laturnus, F., Lauritsen, F. R., Grøn, C., Herrmann, H., Ervens, B., Reese, A., Umschlag, Th., Wicktor, F., Zellner, R., Herrmann, H., Umschlag, Th., Müller, K., Bolzacchini, E., Meinardi, S., Rindone, B., Jenkin, Michael E., Hayman, Garry D., Jensen, N. O., Courtney, M., Hummelshøj, P., Christensen, C. S., Larsen, B. R., Johnson, Matthew S., Hegelund, Flemming, Nelander, Bengt, Kirchner, Frank, Klotz, B., Barnes, Ian, Sørensen, S., Becker, K. H., Etzkorn, T., Platt, U., Wirtz, K., Martín-Reviejo, M., Laturnus, Frank, Martinez, E., Cabañas, B., Aranda, A., Martín, P., Salgado, S., Rodriguez, D., Masclet, P., Jaffrezo, J. L., Hillamo, R., Mellouki, A., Le Calvé, S., Le Bras, G., Moriarty, J., O’Donnell, S., Wenger, J., Sidebottom, H., Mingarrol, M. T. Bomboi, Cosin, S., Pastor, R. Pérez, Alonso, S. García, Sanz, M. J., Bravo, I., Gonzalez, D., Pérez, M. A., Mustafaev, Islam, Mammadova, Saida, Noda, J., Hallquist, M., Langer, S., Ljungström, E., Nohara, K., Kutsuna, S., Ibusuki, T., Oehme, Michael, Kölliker, Stephan, Brombacher, Stephan, Merz, Leo, Pastor, R. Pérez, Alonso, S. García, Cabezas, A. Quejido, Peeters, J., Vereecken, L., El Yazal, J., Pfeffer, Hans-Ulrich, Breuer, Ludger, Platz, J., Nielsen, O. J., Sehested, J., Wallington, T. J., Ball, J. C., Hurley, M. D., Straccia, A. M., Schneider, W. F., Pérez-Casany, M. P., Nebot-Gil, I., Sánchez-Marín, J., Putz, E., Folberth, G., Pfister, G., Weissflog, L., Elansky, N. P., Sørensen, Søren, Barnes, Ian, Becker, K. H., Shao, M., Heiden, A. C., Kley, D., Rockel, P., Wildt, J., Silva, G. V. A., Vasconcelos, M. T., Fernandes, E. O., Santos, A. M. S., Skov, Henrik, Hansen, Asger, Løfstrøm, Per, Lorenzen, Gitte, Stabel, J. R., Wolkoff, P., Pedersen, T., Strom, A. B., Skov, Henrik, Hertel, Ole, Jensen, Finn Palmgren, Hjorth, Jens, Galle, Bosse, Wallin, Svante, Theloke, J., Libuda, H. G., Zabel, F., Touaty, Muriel, Bonsang, Bernard, Ullerstam, M., Langer, S., Ljungström, E., Wenger, John, Bonard, Amélie, Manning, Marcus, Nolan, Sinéad, O’Sullivan, Niamh, Sidebottom, Howard, Wenger, John, Collins, Eoin, Moriarty, Jennie, O’Donnell, Sinéad, Sidebottom, Howard, Wenger, John, Collins, Eoin, Moriarty, Jennie, O’Donnell, Sinéad, Sidebottom, Howard, Wenger, John, Sidebottom, Howard, Chadwick, Paul, O’Leary, Barbara, Treacy, Jack, Wolkoff, Peder, Clausen, Per A., Wilkins, Cornelius K., Hougaard, Karin S., Nielsen, Gunnar D., Zilinskis, Viktors, Jansons, Guntis, Peksens, Aigars, Lazdins, Agris, Arinci, Y. V., Erdöl, N., Ekinci, E., Okutan, H., Manlafalioglu, I., Bakeas, Evangelos B., Siskos, Panayotis A., Viras, Loizos G., Smirnioudi, Vasiliki N., Bottenheim, Jan W., Biesenthal, Thomas, Gong, Wanmin, Makar, Paul, Delmas, Véronique, Menard, Tamara, Tatry, Véronique, Moussafir, Jacques, Thomas, Dominique, Coppalle, Alexis, Ellermann, Thomas, Hertel, Ole, Skov, Henrik, Frohn, Lise, Manscher, Ole H., Friis, Jørgen, Girgzdiene, Rasa, Girgzdys, Aloyzas, Gurevich, N. A., Gårdfeldt, Katarina, Langer, Sarka, Hermans, C., Vandaele, A. C., Carleer, M., Fally, S., Colin, R., Bernath, P. F., Jenouvrier, A., Coquart, B., Mérienne, M. -F., Hertel, Ole, Frohn, Lise, Skov, Henrik, Ellermann, Thomas, Huntrieser, H., Schlager, H., Feigl, C., Kemp, Kåre, Palmgren, Finn, Kiilsholm, Sissi, Rasmussen, Alix, Sørensen, Jens Havskov, Klemm, Otto, Lange, Holger, Larsen, René Wugt, Larsen, Niels Wessel, Nicolaisen, Flemming, Sørensen, Georg Ole, Beukes, Jon Are, Larsen, Poul Bo, Jensen, Steen Solvang, Fenger, Jes, de Leeuw, Gerrit, Kunz, Gerard, Cohen, Leo, Schlünzen, Heinke, Muller, Frank, Schulz, Michael, Tamm, Susanne, Geernaert, Gary, Hertel, Ole, Pedersen, Britta, Geernaert, Lise Lotte Sørensen, Lund, Søren, Vignati, Elisabetta, Jickells, Tim, Spokes, Lucinda, Matei, C., Jinga, O. A., Jinga, D. C., Moliner, R., Braekman-Danheux, C., Fontana, A., Suelves, I., Thieman, T., Vassilev, S., Skov, Henrik, Hertel, Ole, Zlatev, Zahari, Brandt, Jørgen, Bastrup-Birk, Annemarie, Ellermann, Thomas, Frohn, Lise, Vandaele, A. C., Hermans, C., Carleer, M., Tsouli, A., Colin, R., Windsperger, Andreas M., Turi, Kristina, Dworak, Oliver, Zellweger, C., Weingartner, E., Rüttimann, R., Hofer, P., Baltensperger, U., Ziv, A., Iakovleva, E., Palmgren, F., Berkovicz, R., Skov, H., Alastuey, A., Querol, X., Chaves, A., Lopez-Soler, A., Ruiz, C., Andrees, J. M., Allegrini, I., Febo, A., Giusto, M., Angeloni, M., Di Filippo, P., D’Innocenzio, F., Lepore, L., Marconi, A., Arshinov, M. Yu., Belan, B. D., Davydov, D. K., Kovaleskii, V. K., Plotinov, A. P., Pokrovskii, E. V., Sklyadneva, T. K., Tolmachev, G. N., Arshinov, M. Yu., Belan, B. D., Sklyadneva, T. K., Behnke, Wolfgang, Elend, Manfred, Krüger, Ulrich, Zetzsch, Cornelius, Belan, B. D., Arshinov, M. Yu., Davydov, D. K., Kovalevskii, V. K., Plotnikov, A. P., Pokrovskii, E. V., Rasskazchikova, T. M., Sklyadneva, T. K., Tolmachev, G. N., Belan, B. D., Arshinov, M. Yu., Simonenkov, D. V., Tolmachev, G. N., Bilde, Merete, Aker, Pamela M., Börensen, C., Kirchner, U., Scheer, V., Vogt, R., Ellermann, T., Geernaert, L. L. S., Pryor, S. C., Barthelmie, R. J., Feilberg, Anders, Nielsen, Torben, Kamens, Richard M., Freitas, M. C., Marques, A. P., Reis, M. A., Alves, L. C., Ilyinskikh, N. N., Ilyinskikh, I. N., Ilyinskikh, E. N., Johansen, Keld, Stavnsbjerg, Peter, Gabrielsson, Pär, Bak, Flemming, Andersen, Erik, Autrup, Herman, Kamens, Richard, Jang, Myoseon, Strommen, Michael, Leach, Keri, Kirchner, U., Scheer, V., Börensen, C., Vogt, R., Igor, Komov, Svjatoslav, Galiy, Anatoliy, Burlak, Komov, I. L., Istchenko, A. A., Lourenço, M. G., MacTavish, D., Sirois, A., Masclet, Pierre, Jaffrezo, Jean Luc, van der Meulen, A., Milukaite, A., Morkunas, V., Jurgutis, P., Mikelinskiene, A., Nielsen, Torben, Feilberg, Anders, Binderup, Mona Lise, Pineda, M., Palacios, J. M., Garcia, E., Cilleruelo, C., Moliner, R., Popovitcheva, O. B., Trukhin, M. E., Persiantseva, N. M., Buriko, Yu, Starik, A. M., Demirdjian, B., Suzanne, J., Probst, T. U., Rietz, B., Alfassi, Z. B., Pokrovskiy, V. A., Zenobi, R., Bogatyr’ov, V. M., Gun’ko, V. M., Querol, X., Alastuey, A., Lopez-Soler, A., Mantilla, E., Plana, F., Artiño, B., Rauterberg-Wulff, A., Israël, G. W., Rocha, Teresa A. P., Duarte, Armando C., Röhrl, Andreas, Lammel, Gerhard, Spindler, G., Müller, K., Herrmann, H., Strommen, Michael R., Vignati, Elisabetta, de Leeuw, Gerrit, and Berkowicz, Ruwim

Published
1998
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