Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-28T03:29:16.108Z Has data issue: false hasContentIssue false
  • English
  • Français

UV photolysis of polyynes at λ=254 nm and at λ>222 nm

Published online by Cambridge University Press:  30 June 2008

Franco Cataldo ,
Giovanni Strazzulla  and
Susana Iglesias-Groth
Franco Cataldo
Affiliation:
Actinium Chemical Research, Via Casilina 1626/A, 00133 Rome, Italy INAF – Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy
Giovanni Strazzulla
Affiliation:
INAF – Osservatorio Astrofisico di Catania, Via S. Sofia 78, 95123 Catania, Italy
Susana Iglesias-Groth
Affiliation:
Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38200, La Laguna, Canary Islands, Spain e-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

For the first time the kinetic rate constants of the UV photolysis of polyynes C6H2, C8H2, C10H2, C12H2 and C14H2 under rigorously inert atmosphere have been determined in three different solvents: n-hexane, n-heptane and decalin. First- or pseudofirst-order kinetics appear suitable to describe the photolysis of these molecules and k values in the range between 3.0×10−3 s−1 and 4.6×10−3 s−1 have been determined. The unique exception is represented by C6H2 which photolyses more slowly with k=3.2×10−4 s−1. Two different UV sources have been used in the present study: a low-pressure mercury lamp having a monochromatic emission at 253.7 nm and a medium-to high-pressure lamp with a continuous emission between 222 nm and 580 nm. The results are of interest in the understanding, and also the modelling, of the fate of polyynes released by carbon-rich stars in the interstellar medium or the polyynes released by comets in their active phase.

Keywords

astrochemistrydecompositionkineticsphotolysispolyynesUV radiation
Type
Research Article
Information
International Journal of Astrobiology , Volume 7 , Issue 2 , April 2008 , pp. 107 - 116
Copyright
Copyright © 2008 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Arlington, C.A., Ramos, C., Robinson, A.D. & Zwier, T.S. (1999). Ultraviolet photochemistry of diacetylene with alkynes and alkenes: spectroscopic characterization of the products. J. Phys. Chem. A 103, 1294–1299.CrossRefGoogle Scholar
Bandy, R.E., Lakshminarayan, C., Frost, R.K. & Zwier, T.S. (1992). Direct detection of C4H2 photochemical products: possible routes to complex hydrocarbons in planetary atmospheres. Science 258, 1630–1633.CrossRefGoogle ScholarPubMed
Bandy, R.E., Lakshminarayan, C., Frost, R.K. & Zwier, T.S. (1993). The ultraviolet photochemistry of diacetylene: direct detection of primary products of the metastable C4H2*+C4H2 reaction. J. Chem. Phys. 98, 5362–5374.CrossRefGoogle Scholar
Cataldo, F. (2003). Simple generation and detection of polyynes in an arc discharge between graphite electrodes submerged in various solvents. Carbon 41, 2671–2674.CrossRefGoogle Scholar
Cataldo, F. (2004a). Cyanopolyynes: carbon chains formation in a carbon arc mimicking the formation of carbon chains in the circumstellar medium. Int. J. Astrobiol. 3, 237–246.CrossRefGoogle Scholar
Cataldo, F. (2004b). Synthesis of polyynes in a submerged electric arc in organic solvents. Carbon 42, 129–142.CrossRefGoogle Scholar
Cataldo, F. (2004c). Polyynes production in a solvent submerged electric arc between graphite electrodes. Part 3: chemical reactivity toward air, ozone and light. Fullerenes Nanot. Carbon Nanostruct. 12, 633–646.CrossRefGoogle Scholar
Cataldo, F. (2005a). The simplest approach to prepare solutions of polyynes in hydrocarbons. Tetrahedron Lett. 46, 3665–3667.CrossRefGoogle Scholar
Cataldo, F. (2005b). Synthesis of polyynes with the electric arc part 5: analysis of secondary products. Fullerenes Nanot. Carbon Nanostruct. 13, 21–30.CrossRefGoogle Scholar
Cataldo, F. (2006a). Monocyanopolyynes from carbon arc in ammonia: about the relative abundance of polyynes series formed in a carbon arc and those detected in a circumstellar shell of AGB stars. Int. J. Astrobiol. 5, 37–45.CrossRefGoogle Scholar
Cataldo, F. (2006b). Polyynes: Synthesis Properties and Applications, ch. 8, 15, 18. CRC Press (Taylor & Francis Group), Boca Raton, FL.Google Scholar
Cataldo, F. (2006c). Polyynes stability in air and their degradation by ozonolysis. Polym. Degrad. Stab. 91, 317–323.CrossRefGoogle Scholar
Cataldo, F. & Keheyan, Y. (2006). γ-radiolysis of polyynes in heptane. Fullerenes Nanot. Carbon Nanostruct. 14, 83–91.CrossRefGoogle Scholar
Frost, R.K., Zavarin, G.S. & Zwier, T.S. (1995). Ultraviolet photochemistry of diacetylene: Metastable C4H2*+C2H2 reaction in helium and nitrogen. J. Phys. Chem. 99, 9408–9415.CrossRefGoogle Scholar
Glicker, S. & Okabe, H. (1987). Photochemistry of diacetylene. J. Phys. Chem. 91, 437–440.CrossRefGoogle Scholar
Heymann, D. (2008). On the origin of cometary C2 and C3: hydrogen atom migration in diacetylene? Astrophys. J. 679, 1665–1669.CrossRefGoogle Scholar
Kwok, S. (2004). The synthesis of organic and inorganic compounds in evolved stars. Nature 430, 985–991.CrossRefGoogle ScholarPubMed
Kwok, S. (2006). Physics and Chemistry of the Interstellar Medium. University Science Books, New York.Google Scholar
Lagow, R.J. et al. (1995). Synthesis of linear acetylenic carbon: The “sp” carbon allotrope. Science 267, 362–367.CrossRefGoogle ScholarPubMed
Laufer, A.H. & Bass, A.M. (1979). Photochemistry of acetylene. Bimolecular rate constant for the formation of butadiyne and reactions of ethynyl radicals. J. Phys. Chem. 83, 310–313.CrossRefGoogle Scholar
Millar, T.J. (2004). Organic molecules in the interstellar medium. In Astrobiology: Future Perspectives, ed. Ehrenfreund, P., ch. 2. Kluwer Academic Publishers, Dordrecht.Google Scholar
Millar, T.J., Herbst, E. & Bettens, R.P.A. (2000). Large molecules in the envelope surrounding IRC+10216. Mon. Not. Roy. Astron. Soc. 316, 195–203.CrossRefGoogle Scholar
Ninomiya, I. & Naito, T. (1989). Photochemical Synthesis. Academic Press, London.Google Scholar
Okabe, H. (1978). Photochemistry of Small Molecules. Wiley-Interscience, New York.Google Scholar
Platner, D.A., Li, Y. & Houk, K.N. (1995). Modern computational and theoretical aspects of acetylene chemistry. In Modern Acetylene Chemistry, eds Stang, P.J. & Diederich, F., ch. 1, p. 14. Wiley-VCH, Weinhem.Google Scholar
Pola, J., Ouchi, A., Bastl, Z., Vacek, K., Bohácek, J. & Orita, H. (2004). Nanostructured unsaturated carbon from laser-photo-polymerization of diacetylene. Carbon 42, 2521–2526.CrossRefGoogle Scholar
Pontrelli, G.J. (1965). Chemical reactions of the excited states of diacetylene. J. Chem. Phys. 43, 2571–2572.CrossRefGoogle Scholar
Robinson, A.G., Winter, P.R., Ramos, C. & Zwier, T.S. (2000). Ultraviolet photochemistry of diacetylene: Reactions with benzene and toluene. J. Phys. Chem. A 104, 10 312–10 320.CrossRefGoogle Scholar
Roos-Serote, M. (2004). Organic molecules in planetary atmospheres. In Astrobiology: Future Perspectives, ed. Ehrenfreund, P., ch. 6. Kluwer Academic Publishers, Dordrecht.Google Scholar
Seki, K., Nakashima, N. & Nishi, N. (1986). Photochemistry of acetylene at 193 nm: two pathways for diacetylene formation. J. Chem. Phys. 85, 274–279.CrossRefGoogle Scholar
Shi, Y. & Ervin, K.M. (2000). Gas-phase acidity and C—H bond energy of diaceylene. Chem. Phys. Lett. 318, 149–154.CrossRefGoogle Scholar
Smith, N.S., Gazeau, M.C., Khelifi, A. & Raulin, F. (1999). A combined experimental and theoretical study of the catalytic dissociation of methane by the photolysis of acetylene at 185 nm. Planet. Space Sci. 47, 3–10.CrossRefGoogle Scholar
Wrobel, R., Sander, W., Cremer, D. & Kraka, E. (2000). Photochemistry of butatriene – Spectroscopic evidence for the existence of allenylcarbene. J. Phys. Chem. A 104, 3819–3825.CrossRefGoogle Scholar
Yeremin, E.N. (1979). The Foundation of Chemical Kinetics. Mir Publishers, Moscow.Google Scholar
Zelikoff, M. & Aschenbrand, M. (1956). Vacuum ultraviolet photochemistry. Part III. Acetylene at 1849 A. J. Chem. Phys. 24, 1034–1037.CrossRefGoogle Scholar