THE REACTION OF OXYGEN ATOMS WITH METHANE

1938 ◽  
Vol 16b (6) ◽  
pp. 203-209 ◽  
Author(s):  
E. W. R. Steacie ◽  
N. A. D. Parlee
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Discharge Tube ◽  
Oxygen Atoms

The reaction of oxygen atoms, produced by the discharge tube method, with methane has been investigated at temperatures from 30° to 330 °C. The products of the reaction are carbon monoxide, carbon dioxide, and water. Ethane is absent. The activation energy is approximately 8 Kcal. It is concluded that either(a) The reaction postulated by Norrish[Formula: see text]does not occur to any great extent, or(b) The reaction[Formula: see text]has an activation energy greater than 11 to 12 Kcal.

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).

scholarly journals Pyrolysis of phenylmercaptoacetic acid

1968 ◽  
Vol 46 (2) ◽  
pp. 191-197 ◽  
Author(s):  
A. T. C. H. Tan ◽  
A. H. Sehon
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Acetic Acid ◽  
Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Kcal Mole ◽  
Dissociation Process ◽  
First Order

The pyrolysis of phenylmercaptoacetic acid was investigated by the toluene-carrier technique over the temperature range 760–835 °K. The main products of the decomposition were phenyl mercaptan, carbon dioxide, acetic acid, phenyl methyl sulfide, carbon monoxide, and dibenzyl.The overall decomposition was a first-order reaction with respect to phenylmercaptoacetic acid and could be represented by the two parallel steps:[Formula: see text]Reaction [1] was shown to be a homogeneous first-order dissociation process, and its rate constant was represented by the expression[Formula: see text]The activation energy of this reaction, i.e. 58 kcal/mole, was identified with D(C6H5S—CH2COOH).

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.

scholarly journals Supplementary table of wave-lengths of new lines in the secondary spectrum of hydrogen

1926 ◽  
Vol 113 (764) ◽  
pp. 420-432 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Vapour ◽  
Discharge Tube ◽  
Present Author ◽  
Pure Hydrogen ◽  
Coconut Charcoal ◽  
King's College ◽  
Pressure Discharge ◽  
Type Spectrum

During the course of the investigation of the secondary spectrum of hydrogen which is being carried out at King’s College, the present author had to take a number of spectrograms of a low potential and a low-pressure discharge of hydrogen known as the first-type discharge according to Prof. Richardson’s nomenclature. On measuring these first-type spectrum plates, it was found that each of them contained some eighty new lines not recorded in Merton and Barratt’s tables or in the table of additional lines recently published by Tanaka. At first it was suspected that these new lines might be due to some impurities in the discharge tube, but on carefully looking for impurities such as oxygen, nitrogen, carbon, mercury, barium, carbon monoxide, carbon dioxide, ammonia, water vapour, etc., it became evident that there were no impurity lines on our spectrum plates. It may be pointed out that before taking the first-type spectrogram of hydrogen, the discharge tube was being pumped out for a number of days, and it was then washed with hydrogen several times. The discharge tube was provided with a side tube containing coconut charcoal, which was surrounded by liquid air. This liquid-air trap was kept on during all exposures. Pure hydrogen was supplied by means of a palladium tube attached to the side of the discharge tube. This palladium tube was heated in a flame of commercial hydrogen.

REACTION OF OXYGEN ATOMS WITH BENZENE

1961 ◽  
Vol 39 (12) ◽  
pp. 2436-2443 ◽  
Author(s):  
G. Boocock ◽  
R. J. Cvetanović
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Room Temperature ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Kcal Mole ◽  
Volatile Material ◽  
Formed Adduct ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

The reaction of benzene with oxygen atoms produced by mercury photosensitized decomposition of nitrous oxide has been studied in a circulating system at room temperature. The main reaction product is a non-volatile material probably largely aldehydic in character. This is tentatively assumed to result from the rearrangement and polymerization of the initially formed adduct. Smaller amounts of phenol and carbon monoxide are also formed. The rate of formation of carbon monoxide decreases with increasing pressure, suggesting an energy-rich precursor.Oxygen atoms react with benzene much more slowly than with olefines. At 120° cyclopentene reacts about 150 times more quickly than benzene. The activation energy of the reaction of oxygen atoms with benzene has been estimated at 4.6 to 4.9 kcal/mole, with an uncertainty of about 0.7 kcal/mole.

THE THERMAL DECOMPOSITION OF PHENYLACETIC ACID

1960 ◽  
Vol 38 (8) ◽  
pp. 1261-1270 ◽  
Author(s):  
Margaret H. Back ◽  
A. H. Sehon
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Rate Constant ◽  
Phenylacetic Acid ◽  
Order Process ◽  
First Order ◽  
Kinetics Of ◽  
Dissociation Step

The thermal decomposition of phenylacetic acid was investigated by the toluene-carrier technique over the temperature range 587 to 722 °C. The products of the pyrolysis were carbon dioxide, carbon monoxide, hydrogen, methane, dibenzyl, and phenylketene. From the kinetics of the decomposition it was concluded that the reaction[Formula: see text]was a homogeneous, first-order process and that the rate constant of this dissociation step was represented by the expression k = 8 × 1012.e−55,000/RT sec−1. The activation energy of this reaction may be identified with D(C6H5CH2—COOH). The possible reactions of carboxyl radicals are discussed.

The combustion of methane at high temperatures

1954 ◽  
Vol 227 (1168) ◽  
pp. 73-93 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Apparent Activation Energy ◽  
High Temperatures ◽  
Final Stage ◽  
Flow System ◽  
Oxidation Products ◽  
Reaction Proceeds ◽  
Effect Of Surface

The combustion at about 1000°C of methane/air mixtures containing up to 5% of methane has been studied using a flow system. Under such conditions the reaction takes place in a few milliseconds. It is little influenced by surface, is retarded by methane and accelerated by oxygen. Below 500 to 600°C there appears to be a change in the kinetics, but no definite trend of apparent activation energy has been distinguished over the whole temperature range. The effect of surface on the reaction increases at lower temperatures. The reaction proceeds via formaldehyde and carbon monoxide, and the further oxidation of the latter is apparently inhibited by the former or by its oxidation products. This results in an accumulation, in the later stages of reaction, of carbon monoxide, which oxidizes rapidly or ignites when the formaldehyde and the methane have been consumed. Carbon dioxide does, however, appear to some extent before this final stage. Hydrogen also appears, and although its oxidation is retarded in the presence of methane, when the methane oxidizes the hydrogen goes ‘in step’ with it. In the presence of hydrogen the oxidation temperature of carbon monoxide is reduced to that of the hydrogen, but on addition of methane the hydrogen and methane are oxidized together, whilst carbon monoxide remains until the methane has disappeared. Ethane also inhibits the combustion of carbon monoxide, but less effectively than an equal amount of methane.

Sign in / Sign up

Export Citation Format

Share Document