- Modeling of acetylene pyrolysis under steel vacuum carburizing conditions in a tubular flow reactor
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In the present work, the pyrolysis of acetylene was studied under steel vacuum carburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from 650 °C to 1050 °C. The partial pressure of acetylene in the feed mixture was 10 and 20 mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressure of the mixture was 1.6 bar. A kinetic mechanism which consists of seven species and nine reactions has been used in the commercial computational fluid dynamics (CFD) software Fluent. The species transport and reaction model of Fluent was used in the simulations. A comparison of simulated and experimental results is presented in this paper.
- Khan, Rafi Ullah,Bajohr, Siegfried,Graf, Frank,Reimert, Rainer
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- Laser Irradiation of Monomeric Acetylene and the T-Shaped Acetylene Dimer in Xenon and Argon Matrices
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Irradiation of acetylene (4) in an argon matrix with an ArF laser (λ = 193 nm) yields the ethynyl radical C2H (5) and C2 (6). If the same wavelength is used to irradiate 4 in a xenon matrix, only the infrared signal of the compound Xe-C2 (7) can be detected. The same band is found on irradiation at λ = 248 nm (KrF laser) in a xenon matrix, despite the fact that acetylene (4) does not absorb light of this wavelength. Irradiation of the T-shaped acetylene dimer 9 in an argon or xenon matrix at λ = 193 nm yields butadiyne (11) and vinylacetylene (12). However, irradiation with a KrF laser (λ = 248 nm) in a xenon matrix additionally yields cyclobutadiene (13). The dependence of the mechanisms of the fragmentation and dimerization of acetylene (4) on the matrix material is discussed.
- Maier, Günther,Lautz, Christian
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- 3,4-DIAZABENZVALENE, THE AZOALKANE PRECURSOR TO TETRAHEDRANE. SYNTHESIS AND REACTIVITY.
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The title diazene 1 has been synthesized and shown to decompose thermally to cyclobutadiene over a surprisingly small barrier.
- Kaisaki, David A.,Dougherty, Dennis A.
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- Ultraviolet and Polarized Infrared Spectroscopy of Matrix-Isolated Cyclobutadiene and Its Isotopomers
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The UV and polarized IR spectra of argon matrix isolated cyclobutadiene and its 1-d-, 1,2-d2-, 1,4-d2-, 1-13C-, 1,2-13C2-, and 1,4-13C2- labeled derivatives are reported.Above 250 nm, the UV spectrum contains no peaks with an extinction coefficient larger than 10 L M-1 cm-1, but a weak absorption tail extends throughout the UV region.The absorption rises abruptly below 250 nm.The IR peak positions mostly agree with previous reports where these are available.Photoalignment studies support the symmetry assignment of fundamental vibrations and prove that the two Kekule forms interconvert rapidly even at 10 K.The spectral and photochemical effe ts of the presence of an adjacent CO2 molecule in the cyclobutadiene matrix site are elucidated.Its presence causes a substantial retardation of the photofragmentation of cyclobutadiene into two acetylenes.This is attributed to accelerated vibrational energy loss from the cyclobutadiene absorber.
- Arnold, Bradley R.,Michl, Josef
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p. 13348 - 13354
(2007/10/02)
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- Small Rings, 54. Cyclopentadienone
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Cyclopentadienone (1) can be generated by photolysis or pyrolysis of several precursors and isolated in an argon matrix.It dimerizes even on thawing of the matrix (38 K).The IR and UV spectroscopic properties of 1 are discussed.
- Maier, Guenther,Franz, Lothar Hermann,Hartan, Hans-Georg,Lanz, Klaus,Reisenauer, Hans Peter
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p. 3196 - 3204
(2007/10/02)
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- NEUE WEGE ZUM CYCLOBUTADIEN UND METHYLENCYCLOPROPEN
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New routes to cyclobutadiene (2) and methylenecyclopropene (4) are described.Matrix irradiation of cyclopropenylketene (9) gives cyclobutadiene.Flash pyrolysis of 8, 11, 16, 17 and 18 also generates cyclobutadiene, which can be deposited from the gas phase onto a window cooled to 10 K.Methylenecyclopropene is one of he products in the thermal fragmentation of 8 or 14.
- Maier, Guenther,Hoppe, Manfred,Lanz, Klaus,Reisenauer, Hans Peter
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p. 5645 - 5648
(2007/10/02)
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