Gas-phase photolysis of spiropentane at 147.0 nm

1985 ◽  
Vol 63 (12) ◽  
pp. 3593-3596 ◽  
Author(s):  
M. Paller ◽  
R. D. Doepker
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Sulfide ◽  
Gas Phase ◽  
Hydrogen Iodide ◽  
Radical Scavenger ◽  
Relative Importance ◽  
Molecular Processes ◽  
Primary Reaction ◽  
Reaction Channels

The gas-phase photolysis of spiropentane has been investigated using xenon (147.0 nm) resonance radiation. Major products observed in order of decreasing importance are ethylene, aliène, methylacetylene, 1,2-butadiene, acetylene, propylene, and vinylacetylene. Nitric oxide was used as a radical scavenger while hydrogen sulfide and hydrogen iodide were employed as radical interceptors in the determination of the relative importance of radical and molecular processes. CH3/CH2 and CH3C=C• radicals were identified and quantified. Seven primary reaction channels were postulated of which those involving the "elimination" of ethylene were the most predominant accounting for 71% of the photodecomposition.

The gas-phase photolysis of 2-methyl-1,3-butadiene at 123.6 nm

1984 ◽  
Vol 62 (9) ◽  
pp. 1731-1735
Author(s):  
Valerie I. Lang ◽  
Richard D. Doepker
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Sulfide ◽  
Gas Phase ◽  
Quantum Efficiency ◽  
Hydrogen Iodide ◽  
Quantum Yields ◽  
Primary Decomposition ◽  
Radical Scavengers ◽  
Molecule Reaction ◽  
Reaction Channels

The gas-phase photolysis of 2-methyl-1,3-butadiene has been investigated using krypton (123.6 nm) resonance radiation. The observed neutral products of the primary decomposition were vinylacetylene, ethylene, acetylene, methylacetylene, propylene, allene, 2-methy-1-buten-3-yne, pentatriene/1-penten-3-yne, 1,3-butadiene, 2-butyne and butatriene, listed in decreasing order of concentration. There was also evidence of the presence of several radical fragments: CH2/CH3, C2H3, C3H3, and C4H5. Quantum yields for each of the products were determined in the photolysis of 2-methyl-1,3-butadiene, performed both in the presence and the absence of additives. Nitric oxide and oxygen were employed as radical scavengers, while hydrogen sulfide and hydrogen iodide were used as radical interceptors. Twelve primary, neutral molecule, reaction channels were proposed and the quantum efficiency assigned for each. The ionization efficiency of 2-methyl-1,3-butadiene was established as n = 0.55 at 10.03 eV. No products formed exclusively via an ion–molecule pathway were identified and therefore the fate of the C5H8+ ion was not determined.

Vacuum-ultraviolet (147.0 nm and 123.6 nm) photolysis of 1,1-dimethylcyclopropane

1981 ◽  
Vol 59 (3) ◽  
pp. 537-542
Author(s):  
Joseph B. Binkewicz ◽  
Michael Kaplan ◽  
Richard D. Doepker
Keyword(s):  
Gas Phase ◽  
Vacuum Ultraviolet ◽  
Molecular Processes ◽  
Radical Scavengers ◽  
Primary Reaction ◽  
Radical Species ◽  
Molecule Reaction ◽  
Reaction Channels ◽  
A Charge ◽  
Photo Decomposition

The gas-phase photolysis of 1,1-dimethylcyclopropane has been investigated using xenon (147.0 nm) and krypton (123.6 nm) resonance radiation. Major products observed in order of decreasing importance were isobutene, ethylene, hydrogen, 1,3-butadiene 2-methyl-1,3-butadiene, propylene, allene, methylacetylene, and acetylene. Radical scavengers, NO and O2, and radical interceptors, H2S/D2S and HI, were used to determine the relative importance of radical and molecular processes. CH3, C2H3, C3H5, and C4H7 radical species were identified and quantified. Ten primary reaction channels were postulated, of which the elimination of methylene was the most predominant, accounting for 34% of the photo-decomposition at 147.0 nm and 39% at 123.6 nm. Although ionization was established at 123.6 nm (η = 0.10) the nature of a charge transfer or other ion-molecule reaction channel leading to the formation of 2-methyl-1-butene and 2-methyl-2-butene could not be determined.

scholarly journals The Determination of Nitric Oxide in Gas Phase Cigarette Smoke by Non-dispersive Infrared Analysis

1980 ◽  
Vol 10 (2) ◽  
Author(s):  
T. B. Williams
Keyword(s):  
Nitric Oxide ◽  
Gas Phase ◽  
Cigarette Smoke ◽  
Relative Error ◽  
Dead Volume ◽  
High Yield ◽  
Infrared Analysis ◽  
Colorimetric Analysis ◽  
Standard Gas

AbstractNitric oxide in cigarette smoke was conveniently determined by non-dispersive infrared analysis (NDIR). Recoveries of 95 % were obtained with standard gas-air mixtures but recoveries from smoke increased from 87% for high-yield to 91 % for low-yield cigarettes. Relative error was about 4 %. A reduction in the dead volume of Cambridge filter cassettes, to reduce the amount of NO reacted between puffs, increased NO deliveries of cigarettes by 4%. Deliveries of NO were estimated to average 4 % lower due to oxidation, but reaction with other smoke components reduced them further depending upon concentrations. The NO deliveries of cigarettes increased as blend nitrate increased and as the flow of air around cigarettes decreased. Nitric oxide in smoke and in standard gas-air mixtures, determined by non-dispersive infrared (NDIR) spectroscopy, was substantiated by an automated colorimetric analysis. Interfering smoke species were determined and circumvented in both methods.

Sampling and determination of gas-phase hydrogen peroxide following removal of ozone by gas-phase reaction with nitric oxide

1986 ◽  
Vol 58 (8) ◽  
pp. 1857-1865 ◽  
Author(s):  
Roger L. Tanner ◽  
George Y. Markovits ◽  
Eugene M. Ferreri ◽  
Thomas J. Kelly
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
Gas Phase ◽  
Phase Reaction ◽  
Gas Phase Reaction

Photolyse du butyne-2 dans la région de l'uv sous vide

1980 ◽  
Vol 58 (19) ◽  
pp. 2108-2114 ◽  
Author(s):  
Jovette Deschênes ◽  
Hélène Deslauriers ◽  
Guy J. Collin
Keyword(s):  
Nitric Oxide ◽  
Radical Polymerization ◽  
Pressure Effect ◽  
Hydrogen Iodide ◽  
Radical Scavenger ◽  
Methyl Radical ◽  
Vibrationally Excited ◽  
Fast Decrease ◽  
Sous Vide ◽  
Vacuum Uv

The vacuum uv photolysis of gaseous 2-butyne has been studied at 147, 163, and 174 nm. The use of hydrogen iodide as radical scavenger shows the importance of methyl radical formation in the fragmentation of the photoexcited molecule. It is concluded that the principal fragmentation of the photoexcited molecule involves the cleavage of a C—CH3 bond: [Formula: see text] and [Formula: see text]. Unfortunately, it was not possible to scavenge the corresponding C3H3 radicals. From the fast decrease of the transparency of the window it is concluded that an important radical polymerization takes place, even in the presence of oxygen or nitric oxide. Finally, from the pressure effect, it is shown that propyne results from the fragmentation of the vibrationally excited butenyl radical and vinylacetylene arises from the fragmentation of an excited C4H5 radical.

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