PRELIMINARY STUDY OF PHOTOCHEMICAL BEHAVIOR IN THE SYSTEM NITROGEN DIOXIDE – ETHANE

1955 ◽  
Vol 33 (5) ◽  
pp. 843-848
Author(s):  
T. M. Rohr ◽  
W. Albert Noyes Jr.
Keyword(s):  
Nitric Oxide ◽  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Nitrogen Dioxide ◽  
Room Temperature ◽  
Reverse Reaction ◽  
Primary Process ◽  
Photochemical Behavior ◽  
Preliminary Study ◽  
Oxygen Atoms

The addition of ethane to nitrogen dioxide either during exposure to radiation transmitted by pyrex, or afterwards, reduces the amount of oxygen formed. At room temperature this is apparently due to the effectiveness of ethane in promoting the reverse reaction of nitric oxide and oxygen to form nitrogen dioxide. At temperatures over 100° there is a reaction which uses oxygen atoms produced in the primary process. Nitroethane (or nitrosoethane) is formed along with carbon monoxide, carbon dioxide, and some methane. The results suggest that acetaldehyde is an intermediate, but acetaldehyde could not be detected because it would react thermally with nitrogen dioxide. It is not possible to give a complete explanation of the results, but suggestions can be made which might form the basis for later work.

THE EFFECT OF MOLECULAR OXYGEN ON THE REACTION OF OXYGEN ATOMS WITH cis-2-PENTENE

1959 ◽  
Vol 37 (5) ◽  
pp. 953-965 ◽  
Author(s):  
S. Sato ◽  
R. J. Cvetanović
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Nitrogen Dioxide ◽  
Molecular Oxygen ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Pressure Independent ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

The effect of the presence of nitrogen, oxygen, and nitric oxide on the reaction between cis-2-pentene and oxygen atoms has been investigated at room temperature (25 ± 2 °C). For production of oxygen atoms use was made of mercury-photosensitized decomposition of nitrous oxide and of the photolysis of nitrogen dioxide at 3660 Å.In the N2O work, the presence of molecular oxygen induced the formation of acetaldehyde, propanal, methanol, and ethanol. In the NO2 work, the amounts of acetaldehyde, propanal, and ethyl nitrate formed increased rapidly with increasing pressure of molecular oxygen. Possible reaction mechanisms for the formation of these compounds are discussed.Additional information was obtained on the pressure-independent fragmentation in the reaction of oxygen atoms with cis-2-pentene.

THE DECOMPOSITION OF CARBON DIOXIDE BY Hg 6(3P1) AND Hg 6(3P0) ATOMS

1961 ◽  
Vol 39 (11) ◽  
pp. 2244-2250 ◽  
Author(s):  
Otto P. Strausz ◽  
Harry E. Gunning
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Light Intensity ◽  
Chemical Method ◽  
Direct Evidence ◽  
Mercury Vapor ◽  
Maximum Effect ◽  
Electronically Excited ◽  
Oxygen Atoms

Carbon dioxide has been shown to decompose into carbon monoxide and oxygen atoms, when exposed to radiation at 2537 Å, in the presence of mercury vapor. The rate rises steeply with decreasing substrate pressure, and varies directly with the 1.8 ± 0.1 power of the light intensity. The proposed mechanism attributes reaction to the collision of electronically excited CO2 molecules with Hg 6(3P1) atoms. The suppression of reaction at higher substrate pressures is readily explained in terms of collisional deactivation of the excited CO2 species. Nitrogen was found to increase the rate of CO formation; the maximum effect was obtained for a mixture of 7.4 mm nitrogen and 3.74 mm carbon dioxide, in which case the rate was 1.58 times that for pure substrate. It is shown that nitrogen serves to generate metastable Hg 6(3P0) atoms, which can sensitize the decomposition. The reaction might serve as a chemical method for monitoring Hg 6(3P0) atoms. For CO2–N2 mixtures, the rate was found to rise when the reacting system was exposed to radiation at 4047 Å. This is taken as direct evidence of sensitization by higher states of mercury, generated by stepwise excitation, since radiation at 4047 Å converts Hg 6(3P0) to Hg 7(3S1).

THE PHOTO-OXIDATION OF AZOMETHANE

1955 ◽  
Vol 33 (3) ◽  
pp. 496-506 ◽  
Author(s):  
G. R. Hoey ◽  
K. O. Kutschke
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Room Temperature ◽  
Major Product ◽  
Steric Factor ◽  
Primary Process ◽  
Methyl Radicals ◽  
Low Oxygen ◽  
Secondary Product ◽  
Photo Oxidation

The photo-oxidation of azomethane has been studied at low oxygen pressures (0.02 to 1 mm.) in the temperature range ca. 25 °C. to 161 °C. The primary process in the normal photolysis of azomethane is essentially unaffected by the presence of oxygen. Carbon monoxide is probably a secondary product of the oxidation of methyl radicals. Carbon dioxide formation is quite small, and therefore neither methyl radicals nor CH3N=N—CH2 radicals are oxidized appreciably to carbon dioxide. Nitrous oxide, which is a major product of the oxidation, is most likely formed from the oxidation of CH3N=NCH2 radicals. The suggested mechanism of N2O formation is:[Formula: see text] The reaction of methyl radicals with oxygen was found to proceed with a negligible activation energy and a steric factor of the order of 10−2. Evidence for the occurrence of the reactions[Formula: see text]at room temperature was obtained.

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